Ontology change: classification and survey
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paper_title: Evaluation of Ontology Merging Tools in Bioinformatics

paper_content:

Ontologies are being used nowadays in many areas, including bioinformatics. One of the issues in ontology research is the aligning and merging of ontologies. Tools have been developed for ontology merging, but they have not been evaluated for their use in bioinformatics. In this paper we evaluate two of the most well-known ontology merging tools with a bioinformatics perspective. As test ontologies we have used Gene Ontology and Signal-Ontology.
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paper_title: An Environment for Merging and Testing Large Ontologies

paper_content:

Large-scale ontologies are becoming an essential component of many applications including standard search (such as Yahoo and Lycos), ecommerce (such as Amazon and eBay), configuration (such as Dell and PC-Order), and government intelligence (such as DARPA’s High Performance Knowledge Base (HPKB) program). The ontologies are becoming so large that it is not uncommon for distributed teams of people with broad ranges of training to be in charge of the ontology development, design, and maintenance. Standard ontologies (such as UNSPSC) are emerging as well which need to be integrated into large application ontologies, sometimes by people who do not have much training in knowledge representation. This process has generated needs for tools that support broad ranges of users in (1) merging of ontological terms from varied sources, (2) diagnosis of coverage and correctness of ontologies, and (3) maintaining ontologies over time. In this paper, we present a new merging and diagnostic ontology environment called Chimaera, which was developed to address these issues in the context of HPKB. We also report on some initial tests of its effectiveness in merging tasks.
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paper_title: Some Issues on Ontology Integration

paper_content:

The word integration has been used with different ::: meanings in the ontology field. This article ::: aims at clarifying the meaning of the word “integration” ::: and presenting some of the relevant work ::: done in integration. We identify three meanings of ::: ontology “integration”: when building a new ontology ::: reusing (by assembling, extending, specializing ::: or adapting) other ontologies already available; ::: when building an ontology by merging several ::: ontologies into a single one that unifies all of ::: them; when building an application using one or ::: more ontologies. We discuss the different meanings ::: of “integration”, identify the main characteristics ::: of the three different processes and proposethree words to distinguish among those meanings:integration, merge and use.
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paper_title: (SEMANTIC WEB) EVOLUTION THROUGH CHANGE LOGS: PROBLEMS AND SOLUTIONS

paper_content:

Knowledge evolution is currently a hot research topic within the Semantic Web community. This paper investigates a change-based Semantic Web, according to which any modification applied to an ontology should be logged. The merits of this approach for supporting the process of evolution are discussed. Subsequently, a number of basic problems concerning the management of such change logs are introduced, discussed and analyzed. Finally specific techniques and efficient algorithms for managing change logs are provided.
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paper_title: Ontology Mapping: The State of the Art

paper_content:

Ontology mapping is seen as a solution provider in today's landscape of ontology research. As the number of ontologies that are made publicly available and accessible on the Web increases steadily, so does the need for applications to use them. A single ontology is no longer enough to support the tasks envisaged by a distributed environment like the Semantic Web. Multiple ontologies need to be accessed from several applications. Mapping could provide a common layer from which several ontologies could be accessed and hence could exchange information in semantically sound manners. Developing such mappings has been the focus of a variety of works originating from diverse communities over a number of years. In this article we comprehensively review and present these works. We also provide insights on the pragmatics of ontology mapping and elaborate on a theoretical approach for defining ontology mapping.
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paper_title: A translation approach to portable ontology specifications

paper_content:

Abstract To support the sharing and reuse of formally represented knowledge among AI systems, it is useful to define the common vocabulary in which shared knowledge is represented. A specification of a representational vocabulary for a shared domain of discourse—definitions of classes, relations, functions, and other objects—is called an ontology. This paper describes a mechanism for defining ontologies that are portable over representation systems. Definitions written in a standard format for predicate calculus are translated by a system called Ontolingua into specialized representations, including frame-based systems as well as relational languages. This allows researchers to share and reuse ontologies, while retaining the computational benefits of specialized implementations. We discuss how the translation approach to portability addresses several technical problems. One problem is how to accommodate the stylistic and organizational differences among representations while preserving declarative content. Another is how to translate from a very expressive language into restricted languages, remaining system-independent while preserving the computational efficiency of implemented systems. We describe how these problems are addressed by basing Ontolingua itself on an ontology of domain-independent, representational idioms.
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paper_title: Bridging ontology evolution and belief change

paper_content:

One of the crucial tasks towards the realization of the Semantic Web vision is the efficient encoding of human knowledge in ontologies. The proper maintenance of these, usually large, structures and, in particular, their adaptation to new knowledge (ontology evolution) is one of the most challenging problems in current Semantic Web research. In this paper, we uncover a certain gap in current ontology evolution approaches and propose a novel research path based on belief change. We present some ideas in this direction and argue that our approach introduces an interesting new dimension to the problem that is likely to find important applications in the future.
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paper_title: Consistent Evolution of OWL Ontologies

paper_content:

Support for ontology evolution is extremely important in ontology engineering and application of ontologies in dynamic environments. A core aspect in the evolution process is the to guarantee consistency of the ontology when changes occur. In this paper we discuss the consistent evolution of OWL ontologies. We present a model for the semantics of change for OWL ontologies, considering structural, logical, and user-defined consistency. We introduce resolution strategies to ensure that consistency is maintained as the ontology evolves.
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paper_title: Coping with Changing Ontologies in a Distributed Environment

paper_content:

We discuss the problems associated with versioning ontologies in distributed environments. This is an important issue because ontologies can be of great use in structuring and querying intemet information, but many of the Intemet’s characteristics, such as distributed ownership, rapid evolution, and heterogeneity, make ontology management difficult. We present SHOE, a web-based knowledge representation language that supports multiple versions of ontologies. We then discuss the features of SHOE that address ontology versioning, the affects of ontology revision on SHOE web pages, and methods for implementing ontology integration using SHOE’s extension and version mechanisms.
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paper_title: A Component-Based Framework For Ontology Evolution

paper_content:

Support for ontology evolution becomes extremely important in distributed development and use of ontologies. Information about change can be represented in many different ways. We describe these different representations and propose a framework that integrates them. We show how different representations in the framework are related by describing some techniques and heuristics that supplement information in one representation with information from other representations. We present an ontology of change operations, which is the kernel of our framework. 1 Support for Ontology Evolution Ontologies are increasing in popularity, and researchers and developers use them in more and more application areas. Ontologies are used as shared vocabularies, to improve information retrieval, or to help data integration. Neither the ontology development itself nor its product—the ontology— is a single-person enterprise. Large standardized ontologies are often developed by several researchers in parallel (e.g. SUO1 [9]); a number of ontologies grow in the context of peer-to-peer applications (e.g. Edutella [5]); other ontologies are constructed dynamically [2]. Successful applications of ontologies in such uncontrolled, de-centralized and distributed environments require substantial support for change management in ontologies and ontology evolution [7]. Given an ontology O and its two versions, Vold and Vnew, a complete support for change management in an ontology environment includes support for the following tasks.2 Data Transformation: When an ontology version Vold is changed to Vnew, data described by Vold might need to translated to bring it in line with Vnew. For example, if we merge two concepts A and B from Vold into C in Vnew, we must combine instances of A and B as well. http://suo.ieee.org/ Note that Vnew is not necessarily a unique replacement for Vold. There might be several new versions based on the old version, and all of them could exist in parallel. The labels are just used to refer to two versions of an ontology where Vnew has evolved from Vold. Data Access: Even if data is not being transformed, if there exists data conforming to Vold, we often want to access this data and interpret it correctly via Vnew. That is, we should be able to retrieve all data that was accessible via queries in terms of Vold with queries in terms of Vnew. Furthermore, instances of concepts in Vold should be instances of equivalent concepts in Vnew. This task is a very common one in the context of the Semantic Web, where ontologies describe pieces of data on the web. Ontology Update: When we adapt a remote ontology to specific local needs, and the remote ontology changes, we must propagate the changes in the remote ontology to the adapted local ontology [8]. Consistent Reasoning: Ontologies, being formal descriptions, are often used as logical theories. When ontology changes occur, we must analyze the changes to determine whether specific axioms that were valid in Vold are still valid in Vnew. For example, it might be useful to know that a change does not affect the subsumption relationship between two concepts: if A v B is valid in Vold it is also valid in Vnew. While a change in the logical theory will always affects reasoning in general, answers to specific queries may remain unchanged. Verification and Approval: Sometimes developers need to verify and approve ontology changes. This situation often happens when several people are developing a centralized ontology, or when developers want to apply changes selectively. There must be a user interface that simplifies such verification and allows developers to accept or reject specific changes, enabling execution of some changes and rolling back of others. This list of tasks is not exhaustive. The tools that exist today support these tasks in isolation. For example, the KAON framework [10] supports evolution strategies, allowing developers to specify strategies for updating data when changes in an ontology occur. The SHOE versioning system specifies which versions of the ontology the current version is backward compatible with [3]. Many ontology-editing environments (e.g., Protege [1]) provide logs of changes between versions. While these tools support some of the ontologyevolution tasks, there is no interaction or sharing of information among the tools. However, many of these tasks require the same elements in the representation of change. Imple-
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paper_title: Ontology versioning on the Semantic Web

paper_content:

Ontologies are often seen as basic building blocks for the Semantic Web, as they provide a reusable piece of knowledge about a specific domain. However, those pieces of knowledge are not static, but evolve over time. Domain changes, adaptations to different tasks, or changes in the conceptualization require modifications of the ontology. The evolution of ontologies causes operability problems, which will hamper their effective reuse. A versioning mechanism might help to reduce those problems, as it will make the relations between different revisions of an ontology explicit. This paper will discuss the problem of ontology versioning. Inspired by the work done in database schema versioning and program interface versioning, it will also propose building blocks for the most important aspects of a versioning mechanism, i.e., ontology identification and change specification.
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paper_title: A Framework for Ontology Evolution in Collaborative Environments

paper_content:

With the wider use of ontologies in the Semantic Web and as part of production systems, multiple scenarios for ontology maintenance and evolution are emerging. For example, successive ontology versions can be posted on the (Semantic) Web, with users discovering the new versions serendipitously; ontology-development in a collaborative environment can be synchronous or asynchronous; managers of projects may exercise quality control, examining changes from previous baseline versions and accepting or rejecting them before a new baseline is published, and so on. In this paper, we present different scenarios for ontology maintenance and evolution that we have encountered in our own projects and in those of our collaborators. We define several features that categorize these scenarios. For each scenario, we discuss the high-level tasks that an editing environment must support. We then present a unified comprehensive set of tools to support different scenarios in a single framework, allowing users to switch between different modes easily.
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paper_title: An Environment for Merging and Testing Large Ontologies

paper_content:

Large-scale ontologies are becoming an essential component of many applications including standard search (such as Yahoo and Lycos), ecommerce (such as Amazon and eBay), configuration (such as Dell and PC-Order), and government intelligence (such as DARPA’s High Performance Knowledge Base (HPKB) program). The ontologies are becoming so large that it is not uncommon for distributed teams of people with broad ranges of training to be in charge of the ontology development, design, and maintenance. Standard ontologies (such as UNSPSC) are emerging as well which need to be integrated into large application ontologies, sometimes by people who do not have much training in knowledge representation. This process has generated needs for tools that support broad ranges of users in (1) merging of ontological terms from varied sources, (2) diagnosis of coverage and correctness of ontologies, and (3) maintaining ontologies over time. In this paper, we present a new merging and diagnostic ontology environment called Chimaera, which was developed to address these issues in the context of HPKB. We also report on some initial tests of its effectiveness in merging tasks.
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paper_title: ON THE LOGIC OF THEORY CHANGE: PARTIAL MEET CONTRACTION AND REVISION FUNCTIONS

paper_content:

This paper extends earlier work by its authors on formal aspects of the processes of contracting a theory to eliminate a proposition and revising a theory to introduce a proposition. In the course of the earlier work, Gardenfors developed general postulates of a more or less equational nature for such processes, whilst Alchourron and Makinson studied the particular case of contraction functions that are maximal, in the sense of yielding a maximal subset of the theory (or alternatively, of one of its axiomatic bases), that fails to imply the proposition being eliminated. In the present paper, the authors study a broader class, including contraction functions that may be less than maximal. Specifically, they investigate “partial meet contraction functions”, which are defined to yield the intersection of some nonempty family of maximal subsets of the theory that fail to imply the proposition being eliminated. Basic properties of these functions are established: it is shown in particular that they satisfy the Gardenfors postulates, and moreover that they are sufficiently general to provide a representation theorem for those postulates. Some special classes of partial meet contraction functions, notably those that are “relational” and “transitively relational”, are studied in detail, and their connections with certain “supplementary postulates” of Gardenfors investigated, with a further representation theorem established.
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paper_title: Some Issues on Ontology Integration

paper_content:

The word integration has been used with different ::: meanings in the ontology field. This article ::: aims at clarifying the meaning of the word “integration” ::: and presenting some of the relevant work ::: done in integration. We identify three meanings of ::: ontology “integration”: when building a new ontology ::: reusing (by assembling, extending, specializing ::: or adapting) other ontologies already available; ::: when building an ontology by merging several ::: ontologies into a single one that unifies all of ::: them; when building an application using one or ::: more ontologies. We discuss the different meanings ::: of “integration”, identify the main characteristics ::: of the three different processes and proposethree words to distinguish among those meanings:integration, merge and use.
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paper_title: Inconsistencies, Negations and Changes in Ontologies

paper_content:

Ontology management and maintenance are considered cornerstone issues in current Semantic Web applications in which semantic integration and ontological reasoning play a fundamental role. The ability to deal with inconsistency and to accommodate change is of utmost importance in real-world applications of ontological reasoning and management, wherein the need for expressing negated assertions also arises naturally. For this purpose, precise, formal definitions of the the different types of inconsistency and negation in ontologies are required. Unfortunately, ontology languages based on Description Logics (DLs) do not provide enough expressive power to represent axiom negations. Furthermore, there is no single, well-accepted notion of inconsistency and negation in the Semantic Web community, due to the lack of a common and solid foundational framework. In this paper, we propose a general framework accounting for inconsistency, negation and change in ontologies. Different levels of negation and inconsistency in DL-based ontologies are distinguished. We demonstrate how this framework can provide a foundation for reasoning with and management of dynamic ontologies.
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paper_title: Ontology versioning and change detection on the Web

paper_content:

To effectively use ontologies on the Web, it is essential that changes in ontologies are managed well. This paper analyzes the topic of ontology versioning in the context of the Web by looking at the characteristics of the version relation between ontologies and at the identification of online ontologies. Then, it describes the design of a web-based system that helps users to manage changes in ontologies. The system helps to keep different versions of web-based ontologies interoperable, by maintaining not only the transformations between ontologies, but also the conceptual relation between concepts in different versions. The system allows ontology engineers to compare versions of ontology and to specify these conceptual relations. For the visualization of differences, it uses an adaptable rule-based mechanism that finds and classifies changes in RDF-based ontologies.
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paper_title: A model theoretic semantics for ontology versioning

paper_content:

We show that the Semantic Web needs a formal semantics for the various kinds of links between ontologies and other documents. We provide a model theoretic semantics that takes into account ontology extension and ontology versioning. Since the Web is the product of a diverse community, as opposed to a single agent, this semantics accommodates different viewpoints by having different entailment relations for different ontology perspectives. We discuss how this theory can be practically applied to RDF and OWL and provide a theorem that shows how to compute perspective-based entailment using existing logical reasoners. We illustrate these concepts using examples and conclude with a discussion of future work.
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paper_title: Coping with Changing Ontologies in a Distributed Environment

paper_content:

We discuss the problems associated with versioning ontologies in distributed environments. This is an important issue because ontologies can be of great use in structuring and querying intemet information, but many of the Intemet’s characteristics, such as distributed ownership, rapid evolution, and heterogeneity, make ontology management difficult. We present SHOE, a web-based knowledge representation language that supports multiple versions of ontologies. We then discuss the features of SHOE that address ontology versioning, the affects of ontology revision on SHOE web pages, and methods for implementing ontology integration using SHOE’s extension and version mechanisms.
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paper_title: Ontology Mapping: The State of the Art

paper_content:

Ontology mapping is seen as a solution provider in today's landscape of ontology research. As the number of ontologies that are made publicly available and accessible on the Web increases steadily, so does the need for applications to use them. A single ontology is no longer enough to support the tasks envisaged by a distributed environment like the Semantic Web. Multiple ontologies need to be accessed from several applications. Mapping could provide a common layer from which several ontologies could be accessed and hence could exchange information in semantically sound manners. Developing such mappings has been the focus of a variety of works originating from diverse communities over a number of years. In this article we comprehensively review and present these works. We also provide insights on the pragmatics of ontology mapping and elaborate on a theoretical approach for defining ontology mapping.
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paper_title: An Environment for Merging and Testing Large Ontologies

paper_content:

Large-scale ontologies are becoming an essential component of many applications including standard search (such as Yahoo and Lycos), ecommerce (such as Amazon and eBay), configuration (such as Dell and PC-Order), and government intelligence (such as DARPA’s High Performance Knowledge Base (HPKB) program). The ontologies are becoming so large that it is not uncommon for distributed teams of people with broad ranges of training to be in charge of the ontology development, design, and maintenance. Standard ontologies (such as UNSPSC) are emerging as well which need to be integrated into large application ontologies, sometimes by people who do not have much training in knowledge representation. This process has generated needs for tools that support broad ranges of users in (1) merging of ontological terms from varied sources, (2) diagnosis of coverage and correctness of ontologies, and (3) maintaining ontologies over time. In this paper, we present a new merging and diagnostic ontology environment called Chimaera, which was developed to address these issues in the context of HPKB. We also report on some initial tests of its effectiveness in merging tasks.
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paper_title: Some Issues on Ontology Integration

paper_content:

The word integration has been used with different ::: meanings in the ontology field. This article ::: aims at clarifying the meaning of the word “integration” ::: and presenting some of the relevant work ::: done in integration. We identify three meanings of ::: ontology “integration”: when building a new ontology ::: reusing (by assembling, extending, specializing ::: or adapting) other ontologies already available; ::: when building an ontology by merging several ::: ontologies into a single one that unifies all of ::: them; when building an application using one or ::: more ontologies. We discuss the different meanings ::: of “integration”, identify the main characteristics ::: of the three different processes and proposethree words to distinguish among those meanings:integration, merge and use.
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paper_title: SMART : Automated Support for Ontology Merging and Alignment

paper_content:

As researchers in the ontology-design field develop the content of a growing number of ontologies, the need for sharing and reusing this body of knowledge becomes increasingly critical. Aligning and merging existing ontologies, which is usually handled manually, often constitutes a large and tedious portion of the sharing process. We have developed SMART, an algorithm that provides a semi-automatic approach to ontology merging and alignment. SMART assists the ontology developer by performing certain tasks automatically and by guiding the developer to other tasks for which his intervention is required. SMART also determines possible inconsistencies in the state of the ontology that may result from the user’s actions, and suggests ways to remedy these inconsistencies. We define the set of basic operations that are performed during merging and alignment of ontologies, and determine the effects that invocation of each of these operations has on the process. SMART is based on an extremely general knowledge model and, therefore, can be applied across various platforms. 1. Merging Versus Alignment In recent years, researchers have developed many ontologies. These different groups of researchers are now beginning to work with one another, so they must bring together these disparate source ontologies. Two approaches are possible: (1) merging the ontologies to create a single coherent ontology, or (2) aligning the ontologies by establishing links between them and allowing the aligned ontologies to reuse information from one another. As an illustration of the possible processes that establish correspondence between different ontologies, we consider the ontologies that natural languages embody. A researcher trying to find common ground between two such languages may perform one of several tasks. He may create a mapping between the two languages to be used in, say, a machine-translation system. Differences in the ontologies underlying the two languages often do not allow simple one-to-one correspondence, so a mapping must account for these differences. Alternatively, Esperanto language (an international language that was constructed from words in different European languages) was created through merging: All the languages and their underlying ontologies were combined to create a single language. Aligning languages (ontologies) is a third task. Consider how we learn a new domain language that has an extensive vocabulary, such as the language of medicine. The new ontology (the vocabulary of the medical domain) needs to be linked in our minds to the knowledge that we already have (our existing ontology of the world). The creation of these links is alignment. We consider merging and alignment in our work that we describe in this paper. For simplicity, throughout the discussion, we assume that only two ontologies are being merged or aligned at any given time. Figure 1 illustrates the difference between ontology merging and alignment. In merging, a single ontology that is a merged version of the original ontologies is created. Often, the original ontologies cover similar or overlapping domains. For example, the Unified Medical Language System (Humphreys and Lindberg 1993; UMLS 1999) is a large merged ontology that reconciles differences in terminology from various machine-readable biomedical information sources. Another example is the project that was merging the top-most
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paper_title: Ontology Mapping: The State of the Art

paper_content:

Ontology mapping is seen as a solution provider in today's landscape of ontology research. As the number of ontologies that are made publicly available and accessible on the Web increases steadily, so does the need for applications to use them. A single ontology is no longer enough to support the tasks envisaged by a distributed environment like the Semantic Web. Multiple ontologies need to be accessed from several applications. Mapping could provide a common layer from which several ontologies could be accessed and hence could exchange information in semantically sound manners. Developing such mappings has been the focus of a variety of works originating from diverse communities over a number of years. In this article we comprehensively review and present these works. We also provide insights on the pragmatics of ontology mapping and elaborate on a theoretical approach for defining ontology mapping.
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paper_title: A survey of schema-based matching approaches

paper_content:

Schema and ontology matching is a critical problem in many application domains, such as semantic web, schema/ontology integration, data warehouses, e-commerce, etc. Many different matching solutions have been proposed so far. In this paper we present a new classification of schema-based matching techniques that builds on the top of state of the art in both schema and ontology matching. Some innovations are in introducing new criteria which are based on (i) general properties of matching techniques, (ii) interpretation of input information, and (iii) the kind of input information. In particular, we distinguish between approximate and exact techniques at schema-level; and syntactic, semantic, and external techniques at element- and structure-level. Based on the classification proposed we overview some of the recent schema/ontology matching systems pointing which part of the solution space they cover. The proposed classification provides a common conceptual basis, and, hence, can be used for comparing different existing schema/ontology matching techniques and systems as well as for designing new ones, taking advantages of state of the art solutions.
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paper_title: Community-Driven Ontology Matching

paper_content:

We extend the notion of ontology matching to community-driven ontology matching. Primarily, the idea is to enable Web communities to establish and reuse ontology mappings in order to achieve, within those communities, an adequate and timely domain representation, facilitated knowledge exchange, etc. Secondarily, the matching community is provided with the new practice, which is a public alignment reuse. Specifically, we present an approach to construction of a community-driven ontology matching system and discuss its implementation. An analysis of the system usage indicates that our strategy is promising. In particular, the results obtained justify feasibility and usefulness of the community-driven ontology mappings' acquisition and sharing.
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paper_title: Ontology Mapping: The State of the Art

paper_content:

Ontology mapping is seen as a solution provider in today's landscape of ontology research. As the number of ontologies that are made publicly available and accessible on the Web increases steadily, so does the need for applications to use them. A single ontology is no longer enough to support the tasks envisaged by a distributed environment like the Semantic Web. Multiple ontologies need to be accessed from several applications. Mapping could provide a common layer from which several ontologies could be accessed and hence could exchange information in semantically sound manners. Developing such mappings has been the focus of a variety of works originating from diverse communities over a number of years. In this article we comprehensively review and present these works. We also provide insights on the pragmatics of ontology mapping and elaborate on a theoretical approach for defining ontology mapping.
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paper_title: Block matching for ontologies

paper_content:

Ontology matching is a crucial task to enable interoperation between Web applications using different but related ontologies. Today, most of the ontology matching techniques are targeted to find 1:1 mappings. However, block mappings are in fact more pervasive. In this paper, we discuss the block matching problem and suggest that both the mapping quality and the partitioning quality should be considered in block matching. We propose a novel partitioning-based approach to address the block matching issue. It considers both linguistic and structural characteristics of domain entities based on virtual documents, and uses a hierarchical bisection algorithm for partitioning. We set up two kinds of metrics to evaluate of the quality of block matching. The experimental results demonstrate that our approach is feasible.
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paper_title: Schema and ontology matching with COMA++

paper_content:

We demonstrate the schema and ontology matching tool COMA++. It extends our previous prototype COMA utilizing a composite approach to combine different match algorithms [3]. COMA++ implements significant improvements and offers a comprehensive infrastructure to solve large real-world match problems. It comes with a graphical interface enabling a variety of user interactions. Using a generic data representation, COMA++ uniformly supports schemas and ontologies, e.g. the powerful standard languages W3C XML Schema and OWL. COMA++ includes new approaches for ontology matching, in particular the utilization of shared taxonomies. Furthermore, different match strategies can be applied including various forms of reusing previously determined match results and a so-called fragment-based match approach which decomposes a large match problem into smaller problems. Finally, COMA++ cannot only be used to solve match problems but also to comparatively evaluate the effectiveness of different match algorithms and strategies.
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paper_title: Conceptual hierarchies matching: an approach based on discovery of implication rules between concepts

paper_content:

Most research works about ontology or schema matching are based on symmetric similarity measures. By transposing the association rules paradigm, we propose to use asymmetric measures in order to enhance matching. We suggest an extensional and asymmetric matching method based on the discovery of significant implications between concepts described in textual documents. We use a probabilistic model of deviation from independence, named implication intensity. Our method is divided into two consecutive stages: (1) the extraction in documents of relevant terms for each concept; (2) the discovery of significant implications between the concepts. Our method is tested on two benchmarks. The results show that some relevant relations, ignored by a similarity-based matching, can be found thanks to our approach.
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paper_title: Corpus-based schema matching

paper_content:

Schema matching is the problem of identifying corresponding elements in different schemas. Discovering these correspondences or matches is inherently difficult to automate. Past solutions have proposed a principled combination of multiple algorithms. However, these solutions sometimes perform rather poorly due to the lack of sufficient evidence in the schemas being matched. In this paper we show how a corpus of schemas and mappings can be used to augment the evidence about the schemas being matched, so they can be matched better. Such a corpus typically contains multiple schemas that model similar concepts and hence enables us to learn variations in the elements and their properties. We exploit such a corpus in two ways. First, we increase the evidence about each element being matched by including evidence from similar elements in the corpus. Second, we learn statistics about elements and their relationships and use them to infer constraints that we use to prune candidate mappings. We also describe how to use known mappings to learn the importance of domain and generic constraints. We present experimental results that demonstrate corpus-based matching outperforms direct matching (without the benefit of a corpus) in multiple domains.
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paper_title: A survey of schema-based matching approaches

paper_content:

Schema and ontology matching is a critical problem in many application domains, such as semantic web, schema/ontology integration, data warehouses, e-commerce, etc. Many different matching solutions have been proposed so far. In this paper we present a new classification of schema-based matching techniques that builds on the top of state of the art in both schema and ontology matching. Some innovations are in introducing new criteria which are based on (i) general properties of matching techniques, (ii) interpretation of input information, and (iii) the kind of input information. In particular, we distinguish between approximate and exact techniques at schema-level; and syntactic, semantic, and external techniques at element- and structure-level. Based on the classification proposed we overview some of the recent schema/ontology matching systems pointing which part of the solution space they cover. The proposed classification provides a common conceptual basis, and, hence, can be used for comparing different existing schema/ontology matching techniques and systems as well as for designing new ones, taking advantages of state of the art solutions.
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paper_title: Industrial-strength schema matching

paper_content:

Schema matching identifies elements of two given schemas that correspond to each other. Although there are many algorithms for schema matching, little has been written about building a system that can be used in practice. We describe our initial experience building such a system, a customizable schema matcher called Protoplasm.
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paper_title: S-match: an algorithm and an implementation of semantic matching

paper_content:

We think of Match as an operator which takes two graph-like structures (e.g., conceptual hierarchies or ontologies) and produces a mapping between those nodes of the two graphs that correspond semantically to each other. Semantic matching is a novel approach where semantic correspondences are discovered by computing, and returning as a result, the semantic information implicitly or explicitly codified in the labels of nodes and arcs. In this paper we present an algorithm implementing semantic matching, and we discuss its implementation within the S-Match system. We also test S-Match against three state of the art matching systems. The results, though preliminary, look promising, in particular for what concerns precision and recall.
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paper_title: A Tool for Semi-Automated Semantic Schema Mapping: Design and Implementation

paper_content:

Recently, schema mapping has found considerable interest in both research and practice. Determining matching components of database or XML schemas is needed in many applications, e.g. for e-business and data integration. In this paper a complete generic solution of the schema mapping problem is presented. A hybrid semantic schema mapping algorithm which semiautomatically finds mappings between two data representation schemas is introduced. The algorithm finds mappings based on the hierarchical organization of the elements of a term dictionary (WordNet) and on the reuse of already identified matchings. There is also a graphical user interface that allows the user to parameterize the algorithm in an easy and fast way. Special attention was paid to the collaboration of the algorithm with a matching management tool. This collaboration, as proved by the evaluation of the algorithm, resulted in the creation of a generic system for detecting and managing mappings between schemas of various types and sizes.
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paper_title: Schema and ontology matching with COMA++

paper_content:

We demonstrate the schema and ontology matching tool COMA++. It extends our previous prototype COMA utilizing a composite approach to combine different match algorithms [3]. COMA++ implements significant improvements and offers a comprehensive infrastructure to solve large real-world match problems. It comes with a graphical interface enabling a variety of user interactions. Using a generic data representation, COMA++ uniformly supports schemas and ontologies, e.g. the powerful standard languages W3C XML Schema and OWL. COMA++ includes new approaches for ontology matching, in particular the utilization of shared taxonomies. Furthermore, different match strategies can be applied including various forms of reusing previously determined match results and a so-called fragment-based match approach which decomposes a large match problem into smaller problems. Finally, COMA++ cannot only be used to solve match problems but also to comparatively evaluate the effectiveness of different match algorithms and strategies.
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paper_title: Generic Schema Matching with Cupid

paper_content:

Schema matching is a critical step in many applications, such as XML message mapping, data warehouse loading, and schema integration. In this paper, we investigate algorithms for generic schema matching, outside of any particular data model or application. We first present a taxonomy for past solutions, showing that a rich range of techniques is available. We then propose a new algorithm, Cupid, that discovers mappings between schema elements based on their names, data types, constraints, and schema structure, using a broader set of techniques than past approaches. Some of our innovations are the integrated use of linguistic and structural matching, context-dependent matching of shared types, and a bias toward leaf structure where much of the schema content resides. After describing our algorithm, we present experimental results that compare Cupid to two other schema matching systems.
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paper_title: Matching ontologies in open networked systems: techniques and applications

paper_content:

In open networked systems a varying number of nodes interact each other just on the basis of their own independent ontologies and of knowledge discovery requests submitted to the network. Ontology matching techniques are essential to enable knowledge discovery and sharing in order to determine mappings between semantically related concepts of different ontologies. In this paper, we describe the H-Match algorithm and related techniques for performing matching of independent ontologies in open networked systems. A key feature of H-Match is that it can be dynamically configured for adaptation to the semantic complexity of the ontologies to be compared, where the number and type of ontology features that can be exploited during the matching process is not known in advance as it is embedded in the current knowledge request. Furthermore, this number can vary, also for the same ontologies, each time a new matching execution comes into play triggered by a knowledge request. We describe how H-Match enforces this capabilities through a combination of syntactic and semantic techniques as well as through a set of four matching models, namely surface, shallow, deep, and intensive. Then, we describe the application of H-Match and its implementation for knowledge discovery in the framework of the Helios peer-based system. Finally, we present experimental results of using H-Match on different test cases, along with a discussion on precision and recall.
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paper_title: Industrial-strength schema matching

paper_content:

Schema matching identifies elements of two given schemas that correspond to each other. Although there are many algorithms for schema matching, little has been written about building a system that can be used in practice. We describe our initial experience building such a system, a customizable schema matcher called Protoplasm.
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paper_title: Bootstrapping ontology alignment methods with APFEL

paper_content:

Ontology alignment is a prerequisite in order to allow for interoperation between different ontologies and many alignment strategies have been proposed to facilitate the alignment task by (semi-)automatic means. Due to the complexity of the alignment task, manually defined methods for (semi-)automatic alignment rarely constitute an optimal configuration of substrategies from which they have been built. In fact, scrutinizing current ontology alignment methods, one may recognize that most are not optimized for given ontologies. Some few include machine learning for automating the task, but their optimization by machine learning means is mostly restricted to the extensional definition of ontology concepts. With APFEL (Alignment Process Feature Estimation and Learning) we present a machine learning approach that explores the user validation of initial alignments for optimizing alignment methods. The methods are based on extensional and intensional ontology definitions. Core to APFEL is the idea of a generic alignment process, the steps of which may be represented explicitly. APFEL then generates new hypotheses for what might be useful features and similarity assessments and weights them by machine learning approaches. APFEL compares favorably in our experiments to competing approaches.
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paper_title: Discovery-Driven Ontology Evolution

paper_content:

In this paper, we present a methodology for ontology evolution, by focusing on the specific case of multimedia ontology evolution. In particular, we discuss the situation where the ontology needs to be enriched because it does not contain any concept that could be used to explain a new multimedia resource. The paper shows how ontology matching techniques can be used to enforce the discovery of new relevant concepts by probing external knowledge sources using both the information available in the multimedia resource and the knowledge contained in the current version of the ontology.
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paper_title: Coping with Changing Ontologies in a Distributed Environment

paper_content:

We discuss the problems associated with versioning ontologies in distributed environments. This is an important issue because ontologies can be of great use in structuring and querying intemet information, but many of the Intemet’s characteristics, such as distributed ownership, rapid evolution, and heterogeneity, make ontology management difficult. We present SHOE, a web-based knowledge representation language that supports multiple versions of ontologies. We then discuss the features of SHOE that address ontology versioning, the affects of ontology revision on SHOE web pages, and methods for implementing ontology integration using SHOE’s extension and version mechanisms.
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paper_title: Preliminary Evaluation Of Schema Matching Systems

paper_content:

This evaluation of the state-of-the-art schema matching approaches is based on a comprehensive testing of modern systems on various real-world schemas. The results obtained show that there is no matcher that performs best on all types of schemas used. The quality of mappings depends significantly on the approaches to schema matching used and on the tuning of the matcher to the particular schema type. The approach proposed in COMA that combines results of different schema matchers proved its effectiveness in our evaluation.
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paper_title: Ontology Mapping: The State of the Art

paper_content:

Ontology mapping is seen as a solution provider in today's landscape of ontology research. As the number of ontologies that are made publicly available and accessible on the Web increases steadily, so does the need for applications to use them. A single ontology is no longer enough to support the tasks envisaged by a distributed environment like the Semantic Web. Multiple ontologies need to be accessed from several applications. Mapping could provide a common layer from which several ontologies could be accessed and hence could exchange information in semantically sound manners. Developing such mappings has been the focus of a variety of works originating from diverse communities over a number of years. In this article we comprehensively review and present these works. We also provide insights on the pragmatics of ontology mapping and elaborate on a theoretical approach for defining ontology mapping.
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paper_title: OMEN: A Probabilistic Ontology Mapping Tool

paper_content:

Most existing ontology mapping tools are inexact. Inexact ontology mapping rules, if not rectified, result in imprecision in the applications that use them. We describe a framework to probabilistically improve existing ontology mappings using a Bayesian Network. Omen, an Ontology Mapping ENhancer, is based on a set of meta-rules that captures the influence of the ontology structure and the existing matches to match nodes that are neighbours to matched nodes in the two ontologies. We have implemented a protype ontology matcher that can either map concepts across two input ontologies or enhance existing matches between ontology concepts. Preliminary experiments demonstrate that Omen enhances existing ontology mappings in our test cases.
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paper_title: S-match: an algorithm and an implementation of semantic matching

paper_content:

We think of Match as an operator which takes two graph-like structures (e.g., conceptual hierarchies or ontologies) and produces a mapping between those nodes of the two graphs that correspond semantically to each other. Semantic matching is a novel approach where semantic correspondences are discovered by computing, and returning as a result, the semantic information implicitly or explicitly codified in the labels of nodes and arcs. In this paper we present an algorithm implementing semantic matching, and we discuss its implementation within the S-Match system. We also test S-Match against three state of the art matching systems. The results, though preliminary, look promising, in particular for what concerns precision and recall.
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paper_title: H.: A study in empirical and casuistic analysis of ontology mapping results

paper_content:

Many ontology mapping systems nowadays exist. In order to evaluate their strengths and weaknesses, benchmark datasets (ontology collections) have been created, several of which have been used in the most recent edition of the Ontology Alignment Evaluation Initiative (OAEI). While most OAEI tracks rely on straightforward comparison of the results achieved by the mapping systems with some kind of reference mapping created a priori, the 'conference' track (based on the OntoFarmcollection of heterogeneous 'conference organisation' ontologies) instead encompassed multiway manual as well as automated analysis of mapping results themselves, with `correct' and `incorrect' cases determined a posteriori. The manual analysis consisted in simple labelling of discovered mappings plus discussion of selected cases (`casuistics') within a face-to-face consensus building workshop. The automated analysis relied on two different tools: the DRAGO system for testing the consistency of aligned ontologies and the LISp-Minersystem for discovering frequent associations in mapping meta-data including the phenomenon of graph-based mapping patterns. The results potentially provide specific feedback to the developers and users of mining tools, and generally indicate that automated mapping can rarely be successful without considering the larger context and possibly deeper semantics of the entities involved.
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paper_title: An Environment for Merging and Testing Large Ontologies

paper_content:

Large-scale ontologies are becoming an essential component of many applications including standard search (such as Yahoo and Lycos), ecommerce (such as Amazon and eBay), configuration (such as Dell and PC-Order), and government intelligence (such as DARPA’s High Performance Knowledge Base (HPKB) program). The ontologies are becoming so large that it is not uncommon for distributed teams of people with broad ranges of training to be in charge of the ontology development, design, and maintenance. Standard ontologies (such as UNSPSC) are emerging as well which need to be integrated into large application ontologies, sometimes by people who do not have much training in knowledge representation. This process has generated needs for tools that support broad ranges of users in (1) merging of ontological terms from varied sources, (2) diagnosis of coverage and correctness of ontologies, and (3) maintaining ontologies over time. In this paper, we present a new merging and diagnostic ontology environment called Chimaera, which was developed to address these issues in the context of HPKB. We also report on some initial tests of its effectiveness in merging tasks.
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paper_title: A Tool for Semi-Automated Semantic Schema Mapping: Design and Implementation

paper_content:

Recently, schema mapping has found considerable interest in both research and practice. Determining matching components of database or XML schemas is needed in many applications, e.g. for e-business and data integration. In this paper a complete generic solution of the schema mapping problem is presented. A hybrid semantic schema mapping algorithm which semiautomatically finds mappings between two data representation schemas is introduced. The algorithm finds mappings based on the hierarchical organization of the elements of a term dictionary (WordNet) and on the reuse of already identified matchings. There is also a graphical user interface that allows the user to parameterize the algorithm in an easy and fast way. Special attention was paid to the collaboration of the algorithm with a matching management tool. This collaboration, as proved by the evaluation of the algorithm, resulted in the creation of a generic system for detecting and managing mappings between schemas of various types and sizes.
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paper_title: A String Metric for Ontology Alignment

paper_content:

Ontologies are today a key part of every knowledge based system. They provide a source of shared and precisely defined terms, resulting in system interoperability by knowledge sharing and reuse. Unfortunately, the variety of ways that a domain can be conceptualized results in the creation of different ontologies with contradicting or overlapping parts. For this reason ontologies need to be brought into mutual agreement (aligned). One important method for ontology alignment is the comparison of class and property names of ontologies using string-distance metrics. Today quite a lot of such metrics exist in literature. But all of them have been initially developed for different applications and fields, resulting in poor performance when applied in this new domain. In the current paper we present a new string metric for the comparison of names which performs better on the process of ontology alignment as well as to many other field matching problems.
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paper_title: Dynamic Ontologies on the Web

paper_content:

We discuss the problems associated with managing ontologies in distributed environments such as the Web. The Web poses unique problems for the use of ontologies because of the rapid evolution and autonomy of web sites. We present SHOE, a web-based knowledge representation language that supports multiple versions of ontologies. We describe SHOE in the terms of a logic that separates data from ontologies and allows ontologies to provide different perspectives on the data. We then discuss the features of SHOE that address ontology versioning, the effects of ontology revision on SHOE web pages, and methods for implementing ontology integration using SHOE’s extension and version mechanisms.
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paper_title: Schema and ontology matching with COMA++

paper_content:

We demonstrate the schema and ontology matching tool COMA++. It extends our previous prototype COMA utilizing a composite approach to combine different match algorithms [3]. COMA++ implements significant improvements and offers a comprehensive infrastructure to solve large real-world match problems. It comes with a graphical interface enabling a variety of user interactions. Using a generic data representation, COMA++ uniformly supports schemas and ontologies, e.g. the powerful standard languages W3C XML Schema and OWL. COMA++ includes new approaches for ontology matching, in particular the utilization of shared taxonomies. Furthermore, different match strategies can be applied including various forms of reusing previously determined match results and a so-called fragment-based match approach which decomposes a large match problem into smaller problems. Finally, COMA++ cannot only be used to solve match problems but also to comparatively evaluate the effectiveness of different match algorithms and strategies.
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paper_title: Generic Schema Matching with Cupid

paper_content:

Schema matching is a critical step in many applications, such as XML message mapping, data warehouse loading, and schema integration. In this paper, we investigate algorithms for generic schema matching, outside of any particular data model or application. We first present a taxonomy for past solutions, showing that a rich range of techniques is available. We then propose a new algorithm, Cupid, that discovers mappings between schema elements based on their names, data types, constraints, and schema structure, using a broader set of techniques than past approaches. Some of our innovations are the integrated use of linguistic and structural matching, context-dependent matching of shared types, and a bias toward leaf structure where much of the schema content resides. After describing our algorithm, we present experimental results that compare Cupid to two other schema matching systems.
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paper_title: A Large Scale Taxonomy Mapping Evaluation

paper_content:

Matching hierarchical structures, like taxonomies or web directories, is the premise for enabling interoperability among heterogenous data organizations. While the number of new matching solutions is increasing the evaluation issue is still open. This work addresses the problem of comparison for pairwise matching solutions. A methodology is proposed to overcome the issue of scalability. A large scale dataset is developed based on real world case study namely, the web directories of Google, Looksmart and Yahoo!. Finally, an empirical evaluation is performed which compares the most representative solutions for taxonomy matching. We argue that the proposed dataset can play a key role in supporting the empirical analysis for the research effort in the area of taxonomy matching.
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paper_title: A Bayesian Network Approach to Ontology Mapping

paper_content:

This paper presents our ongoing effort on developing a principled methodology for automatic ontology mapping based on BayesOWL, a probabilistic framework we developed for modeling uncertainty in semantic web. In this approach, the source and target ontologies are first translated into Bayesian networks (BN); the concept mapping between the two ontologies are treated as evidential reasoning between the two translated BNs. Probabilities needed for constructing conditional probability tables (CPT) during translation and for measuring semantic similarity during mapping are learned using text classification techniques where each concept in an ontology is associated with a set of semantically relevant text documents, which are obtained by ontology guided web mining. The basic ideas of this approach are validated by positive results from computer experiments on two small real-world ontologies.
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paper_title: SMART : Automated Support for Ontology Merging and Alignment

paper_content:

As researchers in the ontology-design field develop the content of a growing number of ontologies, the need for sharing and reusing this body of knowledge becomes increasingly critical. Aligning and merging existing ontologies, which is usually handled manually, often constitutes a large and tedious portion of the sharing process. We have developed SMART, an algorithm that provides a semi-automatic approach to ontology merging and alignment. SMART assists the ontology developer by performing certain tasks automatically and by guiding the developer to other tasks for which his intervention is required. SMART also determines possible inconsistencies in the state of the ontology that may result from the user’s actions, and suggests ways to remedy these inconsistencies. We define the set of basic operations that are performed during merging and alignment of ontologies, and determine the effects that invocation of each of these operations has on the process. SMART is based on an extremely general knowledge model and, therefore, can be applied across various platforms. 1. Merging Versus Alignment In recent years, researchers have developed many ontologies. These different groups of researchers are now beginning to work with one another, so they must bring together these disparate source ontologies. Two approaches are possible: (1) merging the ontologies to create a single coherent ontology, or (2) aligning the ontologies by establishing links between them and allowing the aligned ontologies to reuse information from one another. As an illustration of the possible processes that establish correspondence between different ontologies, we consider the ontologies that natural languages embody. A researcher trying to find common ground between two such languages may perform one of several tasks. He may create a mapping between the two languages to be used in, say, a machine-translation system. Differences in the ontologies underlying the two languages often do not allow simple one-to-one correspondence, so a mapping must account for these differences. Alternatively, Esperanto language (an international language that was constructed from words in different European languages) was created through merging: All the languages and their underlying ontologies were combined to create a single language. Aligning languages (ontologies) is a third task. Consider how we learn a new domain language that has an extensive vocabulary, such as the language of medicine. The new ontology (the vocabulary of the medical domain) needs to be linked in our minds to the knowledge that we already have (our existing ontology of the world). The creation of these links is alignment. We consider merging and alignment in our work that we describe in this paper. For simplicity, throughout the discussion, we assume that only two ontologies are being merged or aligned at any given time. Figure 1 illustrates the difference between ontology merging and alignment. In merging, a single ontology that is a merged version of the original ontologies is created. Often, the original ontologies cover similar or overlapping domains. For example, the Unified Medical Language System (Humphreys and Lindberg 1993; UMLS 1999) is a large merged ontology that reconciles differences in terminology from various machine-readable biomedical information sources. Another example is the project that was merging the top-most
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paper_title: Formal Model for Ontology Mapping Creation

paper_content:

In a semantic environment data is described by ontologies and heterogeneity problems have to be solved at the ontological level. This means that alignments between ontologies have to be created, most probably during design-time, and used in various run-time processes. Such alignments describe a set of mappings between the source and target ontologies, where the mappings show how instance data from one ontology can be expressed in terms of another ontology. We propose a formal model for mapping creation. Starting from this model we explore how such a model maps onto a design-time graphical tool that can be used in creating alignments between ontologies. We also investigate how such a model helps in expressing the mappings in a logical language, based on the semantic relationships identified using the graphical tool.
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paper_title: Coping with Changing Ontologies in a Distributed Environment

paper_content:

We discuss the problems associated with versioning ontologies in distributed environments. This is an important issue because ontologies can be of great use in structuring and querying intemet information, but many of the Intemet’s characteristics, such as distributed ownership, rapid evolution, and heterogeneity, make ontology management difficult. We present SHOE, a web-based knowledge representation language that supports multiple versions of ontologies. We then discuss the features of SHOE that address ontology versioning, the affects of ontology revision on SHOE web pages, and methods for implementing ontology integration using SHOE’s extension and version mechanisms.
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paper_title: A Semantic Approach for Schema Evolution and Versioning in Object-Oriented Databases

paper_content:

In this paper a semantic approach for the specification and the management of databases with evolving schemata is introduced. It is shown how a general object-oriented model for schema versioning and evolution can be formalized; how the semantics of schema change operations can be defined; how interesting reasoning tasks can be supported, based on an encoding in description logics.
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paper_title: Ontology versioning on the Semantic Web

paper_content:

Ontologies are often seen as basic building blocks for the Semantic Web, as they provide a reusable piece of knowledge about a specific domain. However, those pieces of knowledge are not static, but evolve over time. Domain changes, adaptations to different tasks, or changes in the conceptualization require modifications of the ontology. The evolution of ontologies causes operability problems, which will hamper their effective reuse. A versioning mechanism might help to reduce those problems, as it will make the relations between different revisions of an ontology explicit. This paper will discuss the problem of ontology versioning. Inspired by the work done in database schema versioning and program interface versioning, it will also propose building blocks for the most important aspects of a versioning mechanism, i.e., ontology identification and change specification.
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paper_title: Inconsistencies, Negations and Changes in Ontologies

paper_content:

Ontology management and maintenance are considered cornerstone issues in current Semantic Web applications in which semantic integration and ontological reasoning play a fundamental role. The ability to deal with inconsistency and to accommodate change is of utmost importance in real-world applications of ontological reasoning and management, wherein the need for expressing negated assertions also arises naturally. For this purpose, precise, formal definitions of the the different types of inconsistency and negation in ontologies are required. Unfortunately, ontology languages based on Description Logics (DLs) do not provide enough expressive power to represent axiom negations. Furthermore, there is no single, well-accepted notion of inconsistency and negation in the Semantic Web community, due to the lack of a common and solid foundational framework. In this paper, we propose a general framework accounting for inconsistency, negation and change in ontologies. Different levels of negation and inconsistency in DL-based ontologies are distinguished. We demonstrate how this framework can provide a foundation for reasoning with and management of dynamic ontologies.
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paper_title: Versions of Schema for Object-Oriented Databases

paper_content:

Version control is one of the important database requirements for design environments. Various models of versions have been proposed and implemented. However, research in versions has been focused exclusively on versioning single design objects. In a multi-user design environment where the schema (definition) of the design objects may undergo dynamic changes, it is important to be able to version the schema, as well as version the single design objects. In this paper, we propose a model of versions of schema by extending our model of versions of single objects. In particular, we present the semantics of our model of versions of schema for object-oriented databases, explore issues in implementing the model, and examine a few alternatives to our model of versions of schema.
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paper_title: Resolving inconsistencies in evolving ontologies

paper_content:

Changing a consistent ontology may turn the ontology into an inconsistent state. It is the task of an approach supporting ontology evolution to ensure an ontology evolves from one consistent state into another consistent state. In this paper, we focus on checking consistency of OWL DL ontologies. While existing reasoners allow detecting inconsistencies, determining why the ontology is inconsistent and offering solutions for these inconsistencies is far from trivial. We therefore propose an algorithm to select the axioms from an ontology causing the inconsistency, as well as a set of rules that ontology engineers can use to resolve the detected inconsistency.
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paper_title: Semantics and implementation of schema evolution in object-oriented databases

paper_content:

Object-oriented programming is well-suited to such data-intensive application domains as CAD/CAM, AI, and OIS (office information systems) with multimedia documents. At MCC we have built a prototype object-oriented database system, called ORION. It adds persistence and sharability to objects created and manipulated in applications implemented in an object-oriented programming environment. One of the important requirements of these applications is schema evolution, that is, the ability to dynamically make a wide variety of changes to the database schema. In this paper, following a brief review of the object-oriented data model that we support in ORION, we establish a framework for supporting schema evolution, define the semantics of schema evolution, and discuss its implementation.
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paper_title: Ontology versioning on the Semantic Web

paper_content:

Ontologies are often seen as basic building blocks for the Semantic Web, as they provide a reusable piece of knowledge about a specific domain. However, those pieces of knowledge are not static, but evolve over time. Domain changes, adaptations to different tasks, or changes in the conceptualization require modifications of the ontology. The evolution of ontologies causes operability problems, which will hamper their effective reuse. A versioning mechanism might help to reduce those problems, as it will make the relations between different revisions of an ontology explicit. This paper will discuss the problem of ontology versioning. Inspired by the work done in database schema versioning and program interface versioning, it will also propose building blocks for the most important aspects of a versioning mechanism, i.e., ontology identification and change specification.
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paper_title: A translation approach to portable ontology specifications

paper_content:

Abstract To support the sharing and reuse of formally represented knowledge among AI systems, it is useful to define the common vocabulary in which shared knowledge is represented. A specification of a representational vocabulary for a shared domain of discourse—definitions of classes, relations, functions, and other objects—is called an ontology. This paper describes a mechanism for defining ontologies that are portable over representation systems. Definitions written in a standard format for predicate calculus are translated by a system called Ontolingua into specialized representations, including frame-based systems as well as relational languages. This allows researchers to share and reuse ontologies, while retaining the computational benefits of specialized implementations. We discuss how the translation approach to portability addresses several technical problems. One problem is how to accommodate the stylistic and organizational differences among representations while preserving declarative content. Another is how to translate from a very expressive language into restricted languages, remaining system-independent while preserving the computational efficiency of implemented systems. We describe how these problems are addressed by basing Ontolingua itself on an ontology of domain-independent, representational idioms.
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paper_title: Discovery-Driven Ontology Evolution

paper_content:

In this paper, we present a methodology for ontology evolution, by focusing on the specific case of multimedia ontology evolution. In particular, we discuss the situation where the ontology needs to be enriched because it does not contain any concept that could be used to explain a new multimedia resource. The paper shows how ontology matching techniques can be used to enforce the discovery of new relevant concepts by probing external knowledge sources using both the information available in the multimedia resource and the knowledge contained in the current version of the ontology.
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paper_title: Coping with Changing Ontologies in a Distributed Environment

paper_content:

We discuss the problems associated with versioning ontologies in distributed environments. This is an important issue because ontologies can be of great use in structuring and querying intemet information, but many of the Intemet’s characteristics, such as distributed ownership, rapid evolution, and heterogeneity, make ontology management difficult. We present SHOE, a web-based knowledge representation language that supports multiple versions of ontologies. We then discuss the features of SHOE that address ontology versioning, the affects of ontology revision on SHOE web pages, and methods for implementing ontology integration using SHOE’s extension and version mechanisms.
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paper_title: A Component-Based Framework For Ontology Evolution

paper_content:

Support for ontology evolution becomes extremely important in distributed development and use of ontologies. Information about change can be represented in many different ways. We describe these different representations and propose a framework that integrates them. We show how different representations in the framework are related by describing some techniques and heuristics that supplement information in one representation with information from other representations. We present an ontology of change operations, which is the kernel of our framework. 1 Support for Ontology Evolution Ontologies are increasing in popularity, and researchers and developers use them in more and more application areas. Ontologies are used as shared vocabularies, to improve information retrieval, or to help data integration. Neither the ontology development itself nor its product—the ontology— is a single-person enterprise. Large standardized ontologies are often developed by several researchers in parallel (e.g. SUO1 [9]); a number of ontologies grow in the context of peer-to-peer applications (e.g. Edutella [5]); other ontologies are constructed dynamically [2]. Successful applications of ontologies in such uncontrolled, de-centralized and distributed environments require substantial support for change management in ontologies and ontology evolution [7]. Given an ontology O and its two versions, Vold and Vnew, a complete support for change management in an ontology environment includes support for the following tasks.2 Data Transformation: When an ontology version Vold is changed to Vnew, data described by Vold might need to translated to bring it in line with Vnew. For example, if we merge two concepts A and B from Vold into C in Vnew, we must combine instances of A and B as well. http://suo.ieee.org/ Note that Vnew is not necessarily a unique replacement for Vold. There might be several new versions based on the old version, and all of them could exist in parallel. The labels are just used to refer to two versions of an ontology where Vnew has evolved from Vold. Data Access: Even if data is not being transformed, if there exists data conforming to Vold, we often want to access this data and interpret it correctly via Vnew. That is, we should be able to retrieve all data that was accessible via queries in terms of Vold with queries in terms of Vnew. Furthermore, instances of concepts in Vold should be instances of equivalent concepts in Vnew. This task is a very common one in the context of the Semantic Web, where ontologies describe pieces of data on the web. Ontology Update: When we adapt a remote ontology to specific local needs, and the remote ontology changes, we must propagate the changes in the remote ontology to the adapted local ontology [8]. Consistent Reasoning: Ontologies, being formal descriptions, are often used as logical theories. When ontology changes occur, we must analyze the changes to determine whether specific axioms that were valid in Vold are still valid in Vnew. For example, it might be useful to know that a change does not affect the subsumption relationship between two concepts: if A v B is valid in Vold it is also valid in Vnew. While a change in the logical theory will always affects reasoning in general, answers to specific queries may remain unchanged. Verification and Approval: Sometimes developers need to verify and approve ontology changes. This situation often happens when several people are developing a centralized ontology, or when developers want to apply changes selectively. There must be a user interface that simplifies such verification and allows developers to accept or reject specific changes, enabling execution of some changes and rolling back of others. This list of tasks is not exhaustive. The tools that exist today support these tasks in isolation. For example, the KAON framework [10] supports evolution strategies, allowing developers to specify strategies for updating data when changes in an ontology occur. The SHOE versioning system specifies which versions of the ontology the current version is backward compatible with [3]. Many ontology-editing environments (e.g., Protege [1]) provide logs of changes between versions. While these tools support some of the ontologyevolution tasks, there is no interaction or sharing of information among the tools. However, many of these tasks require the same elements in the representation of change. Imple-
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paper_title: Ontology versioning and change detection on the Web

paper_content:

To effectively use ontologies on the Web, it is essential that changes in ontologies are managed well. This paper analyzes the topic of ontology versioning in the context of the Web by looking at the characteristics of the version relation between ontologies and at the identification of online ontologies. Then, it describes the design of a web-based system that helps users to manage changes in ontologies. The system helps to keep different versions of web-based ontologies interoperable, by maintaining not only the transformations between ontologies, but also the conceptual relation between concepts in different versions. The system allows ontology engineers to compare versions of ontology and to specify these conceptual relations. For the visualization of differences, it uses an adaptable rule-based mechanism that finds and classifies changes in RDF-based ontologies.
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paper_title: A classification of ontology modification

paper_content:

Recent research in ontologies and descriptions logics has focused on compromising between expressiveness and reasoning ability, with many other issues being neglected One major issue that has been neglected is how one should go about in modifying ontologies as inconsistency arises The central concern of this problem is therefore to determine the most rational way of modifying ontologies, such that no extra knowledge would be retained in or retracted from the knowledge base The purpose of this paper is to outline the complexities in this and to present some insights into the problem of ontology modification Description logic (DL) is used in this paper as the underlying logic for the representation of ontology, and ontology modification is performed based on this logic.
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paper_title: Generalizing the AGM postulates: preliminary results and applications

paper_content:

One of the crucial actions any reasoning system must undertake is the updating of its Knowledge Base (KB). This problem is usually referred to as the problem of belief change. The AGM approach, introduced in (Alchourron, Gardenfors, and Makinson 1985), is the dominating paradigm in the area but it makes some non-elementary assumptions about the logic at hand which disallow its direct application in some classes of logics. In this paper, we drop all such assumptions and determine the necessary and sufficient conditions for a logic to support AGMcompliant operators. Our approach is directly applicable to a much broader class of logics. We apply our results to establish connections between the problem of updating in Description Logics (DLs) and the AGM postulates. Finally, we investigate why belief base operators cannot satisfy the AGM postulates in standard logics.
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paper_title: OntoEdit: Multifaceted Inferencing for Ontology Engineering

paper_content:

Ontologies now play an important role for many knowledge-intensive applications for which they provide a source of precisely defined terms. The terms are used for concise communication across people and applications. Tools such as ontology editors facilitate the creation and maintenance of ontologies. OntoEdit is an ontology editor that has been developed keeping five main objectives in mind: 1. Ease of use. 2. Methodology-guided development of ontologies. 3. Ontology development with help of inferencing. 4. Development of ontology axioms. 5. Extensibility through plug-in structure.
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paper_title: The Meaning of Erasing in RDF under the Katsuno-Mendelzon Approach

paper_content:

The basic data model for the Semantic Web is RDF. In this paper we address updates in RDF. It is known that the semantics of updates for data models becomes unclear when the model turns, even slightly, more general than a simple relational structure. Using the framework of KatsunoMendelzon, we define a semantics for updates in RDF. Particularly we explore the behavior of this semantics for the “erase” operator (which in general is not expressible in RDF). Our results include a proposal of sound semantics for RDF updates, a characterization of the maximal RDF graph which captures exactly all consequences of the erase operation expressible in RDF, and complexity results about the computation of this graph and updates in RDF in general.
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paper_title: Bridging ontology evolution and belief change

paper_content:

One of the crucial tasks towards the realization of the Semantic Web vision is the efficient encoding of human knowledge in ontologies. The proper maintenance of these, usually large, structures and, in particular, their adaptation to new knowledge (ontology evolution) is one of the most challenging problems in current Semantic Web research. In this paper, we uncover a certain gap in current ontology evolution approaches and propose a novel research path based on belief change. We present some ideas in this direction and argue that our approach introduces an interesting new dimension to the problem that is likely to find important applications in the future.
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paper_title: Evolving Ontology Evolution

paper_content:

One of the crucial tasks towards the realization of the Semantic Web vision is the efficient encoding of human knowledge in ontologies. Thus, the proper maintenance of these, usually large, structures and, in particular, their adaptation to new knowledge (ontology evolution) is one of the most challenging problems in the current Semantic Web research. In this paper, we uncover a certain gap in the current research area of ontology evolution and propose a research direction based on belief revision. We present some results in this direction and argue that our approach introduces an interesting new dimension to the problem that is likely to find important applications in the future.
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paper_title: Discovery-Driven Ontology Evolution

paper_content:

In this paper, we present a methodology for ontology evolution, by focusing on the specific case of multimedia ontology evolution. In particular, we discuss the situation where the ontology needs to be enriched because it does not contain any concept that could be used to explain a new multimedia resource. The paper shows how ontology matching techniques can be used to enforce the discovery of new relevant concepts by probing external knowledge sources using both the information available in the multimedia resource and the knowledge contained in the current version of the ontology.
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paper_title: Toward Updates in Description Logics

paper_content:

The use of DL systems to add reasoning capabilities to database is now a major trend in convergence between knowledge base and database system but is still confronted with the issue of data update. DL systems provide fact additions and retractions but no real object update mechanisms. We present a semantics for update that favours attribute values to concept membership and deals with incomplete information. After relating our work to an existing previous one on update semantics we address implementation issues.
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paper_title: A Framework for Ontology Evolution in Collaborative Environments

paper_content:

With the wider use of ontologies in the Semantic Web and as part of production systems, multiple scenarios for ontology maintenance and evolution are emerging. For example, successive ontology versions can be posted on the (Semantic) Web, with users discovering the new versions serendipitously; ontology-development in a collaborative environment can be synchronous or asynchronous; managers of projects may exercise quality control, examining changes from previous baseline versions and accepting or rejecting them before a new baseline is published, and so on. In this paper, we present different scenarios for ontology maintenance and evolution that we have encountered in our own projects and in those of our collaborators. We define several features that categorize these scenarios. For each scenario, we discuss the high-level tasks that an editing environment must support. We then present a unified comprehensive set of tools to support different scenarios in a single framework, allowing users to switch between different modes easily.
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paper_title: RUL : A Declarative Update Language for RDF

paper_content:

We propose a declarative update language for RDF graphs which is based on the paradigms of query and view languages RQL and RVL. Our language, called RUL, ensures that the execution of the update primitives on nodes and arcs neither violates the semantics of the RDF model nor the semantics of the given RDFS schema. In addition, RUL supports fine-grained updates at the class and property instance level, set-oriented updates with a deterministic semantics and takes benefit of the full expressive power of RQL for restricting the range of variables to nodes and arcs of RDF graphs.
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paper_title: ON THE LOGIC OF THEORY CHANGE: PARTIAL MEET CONTRACTION AND REVISION FUNCTIONS

paper_content:

This paper extends earlier work by its authors on formal aspects of the processes of contracting a theory to eliminate a proposition and revising a theory to introduce a proposition. In the course of the earlier work, Gardenfors developed general postulates of a more or less equational nature for such processes, whilst Alchourron and Makinson studied the particular case of contraction functions that are maximal, in the sense of yielding a maximal subset of the theory (or alternatively, of one of its axiomatic bases), that fails to imply the proposition being eliminated. In the present paper, the authors study a broader class, including contraction functions that may be less than maximal. Specifically, they investigate “partial meet contraction functions”, which are defined to yield the intersection of some nonempty family of maximal subsets of the theory that fail to imply the proposition being eliminated. Basic properties of these functions are established: it is shown in particular that they satisfy the Gardenfors postulates, and moreover that they are sufficiently general to provide a representation theorem for those postulates. Some special classes of partial meet contraction functions, notably those that are “relational” and “transitively relational”, are studied in detail, and their connections with certain “supplementary postulates” of Gardenfors investigated, with a further representation theorem established.
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paper_title: Weakening conflicting information for iterated revision and knowledge integration

paper_content:

The ability to handle exceptions, to perform iterated belief revision and to integrate information from multiple sources is essential for a commonsense reasoning agent. These important skills are related in the sense that they all rely on resolving inconsistent information. In this paper we develop a novel and useful strategy for conflict resolution, and compare and contrast it with existing strategies. Ideally the process of conflict resolution should conform with the principle of Minimal Change and should result in the minimal loss of information. Our approach to minimizing the loss of information is to weaken information involved in conflicts rather than completely discarding it. We implemented and tested the relative performance of our new strategy in three different ways. Surprisingly, we are able to demonstrate that it provides a computationally effective compilation of the lexicographical strategy; a strategy which is known to have desirable theoretical properties.
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paper_title: Inconsistencies, Negations and Changes in Ontologies

paper_content:

Ontology management and maintenance are considered cornerstone issues in current Semantic Web applications in which semantic integration and ontological reasoning play a fundamental role. The ability to deal with inconsistency and to accommodate change is of utmost importance in real-world applications of ontological reasoning and management, wherein the need for expressing negated assertions also arises naturally. For this purpose, precise, formal definitions of the the different types of inconsistency and negation in ontologies are required. Unfortunately, ontology languages based on Description Logics (DLs) do not provide enough expressive power to represent axiom negations. Furthermore, there is no single, well-accepted notion of inconsistency and negation in the Semantic Web community, due to the lack of a common and solid foundational framework. In this paper, we propose a general framework accounting for inconsistency, negation and change in ontologies. Different levels of negation and inconsistency in DL-based ontologies are distinguished. We demonstrate how this framework can provide a foundation for reasoning with and management of dynamic ontologies.
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paper_title: The description logic handbook: theory, implementation, and applications

paper_content:

Description logics are embodied in several knowledge-based systems and are used to develop various real-life applications. Now in paperback, The Description Logic Handbook provides a thorough account of the subject, covering all aspects of research in this field, namely: theory, implementation, and applications. Its appeal will be broad, ranging from more theoretically oriented readers, to those with more practically oriented interests who need a sound and modern understanding of knowledge representation systems based on description logics. As well as general revision throughout the book, this new edition presents a new chapter on ontology languages for the semantic web, an area of great importance for the future development of the web. In sum, the book will serve as a unique resource for the subject, and can also be used for self-study or as a reference for knowledge representation and artificial intelligence courses.
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paper_title: Knowledge Integration for Description Logics

paper_content:

Description logic reasoners are able to detect incoherences (such as logical inconsistency and concept unsatisfiability) in knowledge bases, but provide little support for resolving them. We propose to recast techniques for propositional inconsistency management into the description logic setting. We show that the additional structure afforded by description logic statements can be used to refine these techniques. Our focus in this paper is on the formal semantics for such techniques, although we do provide high-level decision procedures for the knowledge integration strategies discussed.
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paper_title: Knowledge base revision in description logics

paper_content:

Ontology evolution is an important problem in the Semantic Web research. Recently, Alchourron, Gardenfors and Markinson's (AGM) theory on belief change has been applied to deal with this problem. However, most of current work only focuses on the feasibility of the application of AGM postulates on contraction to description logics (DLs), a family of ontology languages. So the explicit construction of a revision operator is ignored. In this paper, we first generalize the AGM postulates on revision to DLs. We then define two revision operators in DLs. One is the weakening-based revision operator which is defined by weakening of statements in a DL knowledge base and the other is its refinement. We show that both operators capture some notions of minimal change and satisfy the generalized AGM postulates for revision.
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paper_title: Retax++: a tool for browsing and revising ontologies

paper_content:

A squib switch testing apparatus for evaluating the switch parameters which includes a support stand for holding the specimen switch assembly above an interface plate with the switch piston abutting the plate. A generally cylindrical rubber-like washer of a predetermined durometer hardness is interposed between the plate and a piezoelectric transducer. The washer is provided with a central aperture within which is disposed a teflon pin that extends from the transducer to just short of the upper washer surface. Carried by the plate and extending upwardly is a displacement rod which terminates in an optical end portion that includes a narrow lengthwise slit therein. On opposite sides of the slit there is positioned a source of illumination and a photo-detector response to the quantities of light emanating from the source. Thus as the rod is depressed by the activation of the squib a quantity of light proportional to the displacement impinges on the detector whose output is applied to one channel of an oscilloscope. The squib is fired by a linear constant current pulse which is also applied to the scope. The downward movement of the squib piston initially compresses the washer while transmitting the force to the transducer and after this limited movement the pin provides for the force transmission. The transducer under displacement provides an electrical signal to the oscilloscope proportional to the force acting thereon. Thus in one operation the squib switch signature is determined and indicated.
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paper_title: Ontology Revision Using the Concept of Belief Revision

paper_content:

One of the problems identified in the development of ontology is the difficulty in maintaining ontology that often faces on issues of changes in knowledge or perception about things within the community of practice. When new information is added, consistency needs to be maintained to ensure it does not cause inconsistency within existing concepts in ontology. This paper discusses the feasibility of using the concept of belief revision as a basis for ontology revision. It is an effort to the use of expansion, revision and contraction operators of belief revision to revise ontology.
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paper_title: WonderTools? A comparative study of ontological engineering tools

paper_content:

Ontologies are becoming increasingly important in a variety of different fields, such as intelligent searching on the web, knowledge sharing and reuse, knowledge management, etc. Therefore, we expect that the need for tools to support the construction of ontologies will increase significantly in the coming years. In this paper, we investigate several of these tools. We evaluate the tools using two different ontologies: a simple one about university employees, and a second, more complex one, about the structure of a university study. The evaluation was conducted using a framework, which incorporates aspects of ontology buildings and testing, as well as cooperation with other users. Our conclusions are that the usefulness of the tools depends on the level of the users and the stage of development of the ontology.
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paper_title: Description Logics as Ontology Languages for the Semantic Web

paper_content:

The vision of a Semantic Web has recently drawn considerable attention, both from academia and industry. Description logics are often named as one of the tools that can support the Semantic Web and thus help to make this vision reality.
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paper_title: A general diagnosis method for ontologies

paper_content:

The effective debugging of ontologies is an important prerequisite for their successful application and impact on the semantic web. The heart of this debugging process is the diagnosis of faulty knowledge bases. In this paper we define general concepts for the diagnosis of ontologies. Based on these concepts, we provide correct and complete algorithms for the computation of minimal diagnoses of knowledge bases. These concepts and algorithms are broadly applicable since they are independent of a particular variant of an underlying logic (with monotonic semantics) and independent of a particular reasoning system. The practical feasibility of our method is shown by extensive test evaluations.
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paper_title: Debugging OWL-DL Ontologies: A Heuristic Approach

paper_content:

After becoming a W3C Recommendation, OWL is becoming increasingly widely accepted and used. However most people still find it difficult to create and use OWL ontologies. On major difficulty is “debugging” the ontologies – discovering why a reasoners has inferred that a class is “unsatisfiable” (inconsistent). Even for people who do understand OWL and the logical meaning of the underlining description logic, discovering why concepts are unsatisfiable can be difficult. Most modern tableaux reasoners do not provide any explanation as to why the classes are unsatisfiable. This paper presents a ‘black boxed' heuristic approach based on identifying common errors and inferences.
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paper_title: Weakening conflicting information for iterated revision and knowledge integration

paper_content:

The ability to handle exceptions, to perform iterated belief revision and to integrate information from multiple sources is essential for a commonsense reasoning agent. These important skills are related in the sense that they all rely on resolving inconsistent information. In this paper we develop a novel and useful strategy for conflict resolution, and compare and contrast it with existing strategies. Ideally the process of conflict resolution should conform with the principle of Minimal Change and should result in the minimal loss of information. Our approach to minimizing the loss of information is to weaken information involved in conflicts rather than completely discarding it. We implemented and tested the relative performance of our new strategy in three different ways. Surprisingly, we are able to demonstrate that it provides a computationally effective compilation of the lexicographical strategy; a strategy which is known to have desirable theoretical properties.
---
paper_title: Inconsistencies, Negations and Changes in Ontologies

paper_content:

Ontology management and maintenance are considered cornerstone issues in current Semantic Web applications in which semantic integration and ontological reasoning play a fundamental role. The ability to deal with inconsistency and to accommodate change is of utmost importance in real-world applications of ontological reasoning and management, wherein the need for expressing negated assertions also arises naturally. For this purpose, precise, formal definitions of the the different types of inconsistency and negation in ontologies are required. Unfortunately, ontology languages based on Description Logics (DLs) do not provide enough expressive power to represent axiom negations. Furthermore, there is no single, well-accepted notion of inconsistency and negation in the Semantic Web community, due to the lack of a common and solid foundational framework. In this paper, we propose a general framework accounting for inconsistency, negation and change in ontologies. Different levels of negation and inconsistency in DL-based ontologies are distinguished. We demonstrate how this framework can provide a foundation for reasoning with and management of dynamic ontologies.
---
paper_title: Knowledge Integration for Description Logics

paper_content:

Description logic reasoners are able to detect incoherences (such as logical inconsistency and concept unsatisfiability) in knowledge bases, but provide little support for resolving them. We propose to recast techniques for propositional inconsistency management into the description logic setting. We show that the additional structure afforded by description logic statements can be used to refine these techniques. Our focus in this paper is on the formal semantics for such techniques, although we do provide high-level decision procedures for the knowledge integration strategies discussed.
---
paper_title: Resolving inconsistencies in evolving ontologies

paper_content:

Changing a consistent ontology may turn the ontology into an inconsistent state. It is the task of an approach supporting ontology evolution to ensure an ontology evolves from one consistent state into another consistent state. In this paper, we focus on checking consistency of OWL DL ontologies. While existing reasoners allow detecting inconsistencies, determining why the ontology is inconsistent and offering solutions for these inconsistencies is far from trivial. We therefore propose an algorithm to select the axioms from an ontology causing the inconsistency, as well as a set of rules that ontology engineers can use to resolve the detected inconsistency.
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paper_title: A Fine-Grained Approach to Resolving Unsatisfiable Ontologies

paper_content:

In the Semantic Web, inconsistencies in OWL on- tologies may easily occur. Existing approaches ei- ther identify the minimally unsatisfiable sub-ontologies or calculate the maximally satisfiable sub-ontologies. However practical problems remain; it is not clear which axioms or which parts of axioms should be se- lected for repair, and how to repair those axioms. In this paper, we address this limitation by proposing a fine-grained approach to resolving unsatisfiable ontolo- gies. We revise the axiom tracing technique first pro- posed by Baader and Hollunder, so as to track which parts of the problematic axioms cause the unsatisfiabil- ity. Moreover, we support ontology users in rewriting problematic axioms. In order to minimise the impact of changes and prevent unintended entailment loss, harm- ful and helpful changes are identified and provided as guidelines. Based on the methods described we present a preliminary version of an interactive debugging tool and demonstrate its applicability in practice.
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paper_title: Finding Maximally Satisfiable Terminologies for the Description Logic ALC

paper_content:

For ontologies represented as Description Logic Tboxes, optimised DL reasoners are able to detect logical errors, but there is comparatively limited support for resolving such problems. One possible remedy is to weaken the available information to the extent that the errors disappear, but to limit the weakening process as much as possible. The most obvious way to do so is to remove just enough Tbox sentences to eliminate the errors. In this paper we propose a tableau-like procedure for finding maximally concept-satisfiable terminologies represented in the description logic ALC. We discuss some optimisation techniques, and report on preliminary, but encouraging, experimental results.
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paper_title: PROMPTDIFF: A Fixed-Point Algorithm for Comparing Ontology Versions

paper_content:

As ontology development becomes a more ubiquitous and collaborative process, the developers face the problem of maintaining versions of ontologies akin to maintaining versions of software code in large software projects. Versioning systems for software code provide mechanisms for tracking versions, checking out versions for editing, comparing different versions, and so on. We can directly reuse many of these mechanisms for ontology versioning. However, version comparison for code is based on comparing text files--an approach that does not work for comparing ontologies. Two ontologies can be identical but have different text representation. We have developed the PROMPTDIFF algorithm, which integrates different heuristic matchers for comparing ontology versions. We combine these matchers in a fixed-point manner, using the results of one matcher as an input for others until the matchers produce no more changes. The current implementation includes ten matchers but the approach is easily extendable to an arbitrary number of matchers. Our evaluation showed that PROMPTDIFF correctly identified 96% of the matches in ontology versions from large projects.
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paper_title: A model theoretic semantics for ontology versioning

paper_content:

We show that the Semantic Web needs a formal semantics for the various kinds of links between ontologies and other documents. We provide a model theoretic semantics that takes into account ontology extension and ontology versioning. Since the Web is the product of a diverse community, as opposed to a single agent, this semantics accommodates different viewpoints by having different entailment relations for different ontology perspectives. We discuss how this theory can be practically applied to RDF and OWL and provide a theorem that shows how to compute perspective-based entailment using existing logical reasoners. We illustrate these concepts using examples and conclude with a discussion of future work.
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paper_title: Data Migration for Ontology Evolution

paper_content:

Ontology is the conceptual backbone that provides meaning to data on the semantic web. However, ontology is not a static resource and may evolve over time, which often leaves the meaning of data in an undefined or inconsistent state. It is thus very important to have a method to preserve the data and its meaning when ontology changes. This paper proposed a general method that solves the problem using data migration. It analyzed some of the issues in the method including separation of ontology and data, migration specification, migration result and migration algorithm. The paper also instantiates the general mothod in RDF(S) as an example. The RDF(S) example itself is a simple but complete method for migrating RDF data when RDFS ontology changes.
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paper_title: Coping with Changing Ontologies in a Distributed Environment

paper_content:

We discuss the problems associated with versioning ontologies in distributed environments. This is an important issue because ontologies can be of great use in structuring and querying intemet information, but many of the Intemet’s characteristics, such as distributed ownership, rapid evolution, and heterogeneity, make ontology management difficult. We present SHOE, a web-based knowledge representation language that supports multiple versions of ontologies. We then discuss the features of SHOE that address ontology versioning, the affects of ontology revision on SHOE web pages, and methods for implementing ontology integration using SHOE’s extension and version mechanisms.
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paper_title: A Component-Based Framework For Ontology Evolution

paper_content:

Support for ontology evolution becomes extremely important in distributed development and use of ontologies. Information about change can be represented in many different ways. We describe these different representations and propose a framework that integrates them. We show how different representations in the framework are related by describing some techniques and heuristics that supplement information in one representation with information from other representations. We present an ontology of change operations, which is the kernel of our framework. 1 Support for Ontology Evolution Ontologies are increasing in popularity, and researchers and developers use them in more and more application areas. Ontologies are used as shared vocabularies, to improve information retrieval, or to help data integration. Neither the ontology development itself nor its product—the ontology— is a single-person enterprise. Large standardized ontologies are often developed by several researchers in parallel (e.g. SUO1 [9]); a number of ontologies grow in the context of peer-to-peer applications (e.g. Edutella [5]); other ontologies are constructed dynamically [2]. Successful applications of ontologies in such uncontrolled, de-centralized and distributed environments require substantial support for change management in ontologies and ontology evolution [7]. Given an ontology O and its two versions, Vold and Vnew, a complete support for change management in an ontology environment includes support for the following tasks.2 Data Transformation: When an ontology version Vold is changed to Vnew, data described by Vold might need to translated to bring it in line with Vnew. For example, if we merge two concepts A and B from Vold into C in Vnew, we must combine instances of A and B as well. http://suo.ieee.org/ Note that Vnew is not necessarily a unique replacement for Vold. There might be several new versions based on the old version, and all of them could exist in parallel. The labels are just used to refer to two versions of an ontology where Vnew has evolved from Vold. Data Access: Even if data is not being transformed, if there exists data conforming to Vold, we often want to access this data and interpret it correctly via Vnew. That is, we should be able to retrieve all data that was accessible via queries in terms of Vold with queries in terms of Vnew. Furthermore, instances of concepts in Vold should be instances of equivalent concepts in Vnew. This task is a very common one in the context of the Semantic Web, where ontologies describe pieces of data on the web. Ontology Update: When we adapt a remote ontology to specific local needs, and the remote ontology changes, we must propagate the changes in the remote ontology to the adapted local ontology [8]. Consistent Reasoning: Ontologies, being formal descriptions, are often used as logical theories. When ontology changes occur, we must analyze the changes to determine whether specific axioms that were valid in Vold are still valid in Vnew. For example, it might be useful to know that a change does not affect the subsumption relationship between two concepts: if A v B is valid in Vold it is also valid in Vnew. While a change in the logical theory will always affects reasoning in general, answers to specific queries may remain unchanged. Verification and Approval: Sometimes developers need to verify and approve ontology changes. This situation often happens when several people are developing a centralized ontology, or when developers want to apply changes selectively. There must be a user interface that simplifies such verification and allows developers to accept or reject specific changes, enabling execution of some changes and rolling back of others. This list of tasks is not exhaustive. The tools that exist today support these tasks in isolation. For example, the KAON framework [10] supports evolution strategies, allowing developers to specify strategies for updating data when changes in an ontology occur. The SHOE versioning system specifies which versions of the ontology the current version is backward compatible with [3]. Many ontology-editing environments (e.g., Protege [1]) provide logs of changes between versions. While these tools support some of the ontologyevolution tasks, there is no interaction or sharing of information among the tools. However, many of these tasks require the same elements in the representation of change. Imple-
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paper_title: Ontology versioning on the Semantic Web

paper_content:

Ontologies are often seen as basic building blocks for the Semantic Web, as they provide a reusable piece of knowledge about a specific domain. However, those pieces of knowledge are not static, but evolve over time. Domain changes, adaptations to different tasks, or changes in the conceptualization require modifications of the ontology. The evolution of ontologies causes operability problems, which will hamper their effective reuse. A versioning mechanism might help to reduce those problems, as it will make the relations between different revisions of an ontology explicit. This paper will discuss the problem of ontology versioning. Inspired by the work done in database schema versioning and program interface versioning, it will also propose building blocks for the most important aspects of a versioning mechanism, i.e., ontology identification and change specification.
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paper_title: A Framework for Ontology Evolution in Collaborative Environments

paper_content:

With the wider use of ontologies in the Semantic Web and as part of production systems, multiple scenarios for ontology maintenance and evolution are emerging. For example, successive ontology versions can be posted on the (Semantic) Web, with users discovering the new versions serendipitously; ontology-development in a collaborative environment can be synchronous or asynchronous; managers of projects may exercise quality control, examining changes from previous baseline versions and accepting or rejecting them before a new baseline is published, and so on. In this paper, we present different scenarios for ontology maintenance and evolution that we have encountered in our own projects and in those of our collaborators. We define several features that categorize these scenarios. For each scenario, we discuss the high-level tasks that an editing environment must support. We then present a unified comprehensive set of tools to support different scenarios in a single framework, allowing users to switch between different modes easily.
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paper_title: On the Foundations of Computing Deltas between RDF models

paper_content:

The ability to compute the differences that exist between two RDF models is an important step to cope with the evolving nature of the Semantic Web (SW). In particular, RDF Deltas can be employed to reduce the amount of data that need to be exchanged and managed over the network and hence build advanced SW synchronization and versioning services. By considering Deltas as sets of change operations, in this paper we study various RDF comparison functions in conjunction with the semantics of the underlying change operations and formally analyze their possible combinations in terms of correctness, minimality, semantic identity and redundancy properties.
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paper_title: Dynamic Ontologies on the Web

paper_content:

We discuss the problems associated with managing ontologies in distributed environments such as the Web. The Web poses unique problems for the use of ontologies because of the rapid evolution and autonomy of web sites. We present SHOE, a web-based knowledge representation language that supports multiple versions of ontologies. We describe SHOE in the terms of a logic that separates data from ontologies and allows ontologies to provide different perspectives on the data. We then discuss the features of SHOE that address ontology versioning, the effects of ontology revision on SHOE web pages, and methods for implementing ontology integration using SHOE’s extension and version mechanisms.
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paper_title: Ontology versioning and change detection on the Web

paper_content:

To effectively use ontologies on the Web, it is essential that changes in ontologies are managed well. This paper analyzes the topic of ontology versioning in the context of the Web by looking at the characteristics of the version relation between ontologies and at the identification of online ontologies. Then, it describes the design of a web-based system that helps users to manage changes in ontologies. The system helps to keep different versions of web-based ontologies interoperable, by maintaining not only the transformations between ontologies, but also the conceptual relation between concepts in different versions. The system allows ontology engineers to compare versions of ontology and to specify these conceptual relations. For the visualization of differences, it uses an adaptable rule-based mechanism that finds and classifies changes in RDF-based ontologies.
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paper_title: Ontology-based Web agents

paper_content:

This paper describes SHOE, a set of Simple HTML Ontology Extensions which allow World-Wide Web authors to annotate their pages with semantic knowledge such as “I am a graduate student” or “This person is my graduate advisor”. These annotations are expressed in terms of ontological knowledge which can be generated by using or extending standard ontologies available on the Web. This makes it possible to ask Web agent queries such as “Find me all graduate students in Maryland who are working on a project funded by DoD initiative 123-4567”, instead of simplistic keyword searches enabled by current search engines. We have also developed a web-crawling agent, Expos´ e, which interns SHOE knowledge from web documents, making these kinds queries a reality.
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paper_title: SemVersion: A Versioning System for RDF and Ontologies

paper_content:

Knowledge domains and their semantic representations via ontologies are typically subject to change in practical applications. Additionally, engineering of ontologies often takes place in distributed settings where multiple independent users interact. Therefore, change management for ontologies becomes a crucial aspect for any kind of ontology management environment. This paper introduces a new RDF-centric versioning approach and an implementation called SemVersion. SemVersion provides structural and semantic versioning for RDF models and RDFbased ontology languages like RDFS. The requirements for our system are derived from a practical scenario in the librarian domain, i.e. the
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paper_title: Some Issues on Ontology Integration

paper_content:

The word integration has been used with different ::: meanings in the ontology field. This article ::: aims at clarifying the meaning of the word “integration” ::: and presenting some of the relevant work ::: done in integration. We identify three meanings of ::: ontology “integration”: when building a new ontology ::: reusing (by assembling, extending, specializing ::: or adapting) other ontologies already available; ::: when building an ontology by merging several ::: ontologies into a single one that unifies all of ::: them; when building an application using one or ::: more ontologies. We discuss the different meanings ::: of “integration”, identify the main characteristics ::: of the three different processes and proposethree words to distinguish among those meanings:integration, merge and use.
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paper_title: A classification of ontology modification

paper_content:

Recent research in ontologies and descriptions logics has focused on compromising between expressiveness and reasoning ability, with many other issues being neglected One major issue that has been neglected is how one should go about in modifying ontologies as inconsistency arises The central concern of this problem is therefore to determine the most rational way of modifying ontologies, such that no extra knowledge would be retained in or retracted from the knowledge base The purpose of this paper is to outline the complexities in this and to present some insights into the problem of ontology modification Description logic (DL) is used in this paper as the underlying logic for the representation of ontology, and ontology modification is performed based on this logic.
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paper_title: Coping with Changing Ontologies in a Distributed Environment

paper_content:

We discuss the problems associated with versioning ontologies in distributed environments. This is an important issue because ontologies can be of great use in structuring and querying intemet information, but many of the Intemet’s characteristics, such as distributed ownership, rapid evolution, and heterogeneity, make ontology management difficult. We present SHOE, a web-based knowledge representation language that supports multiple versions of ontologies. We then discuss the features of SHOE that address ontology versioning, the affects of ontology revision on SHOE web pages, and methods for implementing ontology integration using SHOE’s extension and version mechanisms.
---
paper_title: Ontology Mapping: The State of the Art

paper_content:

Ontology mapping is seen as a solution provider in today's landscape of ontology research. As the number of ontologies that are made publicly available and accessible on the Web increases steadily, so does the need for applications to use them. A single ontology is no longer enough to support the tasks envisaged by a distributed environment like the Semantic Web. Multiple ontologies need to be accessed from several applications. Mapping could provide a common layer from which several ontologies could be accessed and hence could exchange information in semantically sound manners. Developing such mappings has been the focus of a variety of works originating from diverse communities over a number of years. In this article we comprehensively review and present these works. We also provide insights on the pragmatics of ontology mapping and elaborate on a theoretical approach for defining ontology mapping.
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paper_title: Some Issues on Ontology Integration

paper_content:

The word integration has been used with different ::: meanings in the ontology field. This article ::: aims at clarifying the meaning of the word “integration” ::: and presenting some of the relevant work ::: done in integration. We identify three meanings of ::: ontology “integration”: when building a new ontology ::: reusing (by assembling, extending, specializing ::: or adapting) other ontologies already available; ::: when building an ontology by merging several ::: ontologies into a single one that unifies all of ::: them; when building an application using one or ::: more ontologies. We discuss the different meanings ::: of “integration”, identify the main characteristics ::: of the three different processes and proposethree words to distinguish among those meanings:integration, merge and use.
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paper_title: Evaluation of Ontology Merging Tools in Bioinformatics

paper_content:

Ontologies are being used nowadays in many areas, including bioinformatics. One of the issues in ontology research is the aligning and merging of ontologies. Tools have been developed for ontology merging, but they have not been evaluated for their use in bioinformatics. In this paper we evaluate two of the most well-known ontology merging tools with a bioinformatics perspective. As test ontologies we have used Gene Ontology and Signal-Ontology.
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paper_title: Ontology Merging for Federated Ontologies on the Semantic Web

paper_content:

One of the core challenges for the Semantic Web is the aspect of decentralization. Local structures can be modeled by ontologies. However, in order to support global communication and knowledge exchange, mechanisms have to be developed for integrating the local systems. We adopt the database approach of autonomous federated database systems and consider an architecture for federated ontologies for the Semantic Web as starting point of our work. We identify the need for merging specific ontologies for developing federated, but still autonomous web systems. We present the method FCA–MERGE for merging ontologies following a bottom-up approach which offers a structural description of the merging process. The method is guided by application-specific instances of the given source ontologies that are to be merged. We apply techniques from natural language processing and formal concept analysis to derive a lattice of concepts as a structural result of FCA–MERGE. The generated result is then explored and transformed into the merged ontology with human interaction.
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paper_title: The PROMPT Suite: Interactive Tools for Ontology Merging and Mapping

paper_content:

Researchers in the ontology-design field have developed the content for ontologies in many domain areas. This distributed nature of ontology development has led to a large number of ontologies covering overlapping domains. In order for these ontologies to be reused, they first need to be merged or aligned to one another. We developed a suite of tools for managing multiple ontologies. These suite provides users with a uniform framework for comparing, aligning, and merging ontologies, maintaining versions, translating between different formalisms. Two of the tools in the suite support semi-automatic ontology merging: IPROMPT is an interactive ontology-merging tool that guides the user through the merging process, presenting him with suggestions for next steps and identifying inconsistencies and potential problems. ANCHORPROMPT uses a graph structure of ontologies to find correlation between concepts and to provide additional information for IPROMPT.
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paper_title: Coping with Changing Ontologies in a Distributed Environment

paper_content:

We discuss the problems associated with versioning ontologies in distributed environments. This is an important issue because ontologies can be of great use in structuring and querying intemet information, but many of the Intemet’s characteristics, such as distributed ownership, rapid evolution, and heterogeneity, make ontology management difficult. We present SHOE, a web-based knowledge representation language that supports multiple versions of ontologies. We then discuss the features of SHOE that address ontology versioning, the affects of ontology revision on SHOE web pages, and methods for implementing ontology integration using SHOE’s extension and version mechanisms.
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paper_title: An Environment for Merging and Testing Large Ontologies

paper_content:

Large-scale ontologies are becoming an essential component of many applications including standard search (such as Yahoo and Lycos), ecommerce (such as Amazon and eBay), configuration (such as Dell and PC-Order), and government intelligence (such as DARPA’s High Performance Knowledge Base (HPKB) program). The ontologies are becoming so large that it is not uncommon for distributed teams of people with broad ranges of training to be in charge of the ontology development, design, and maintenance. Standard ontologies (such as UNSPSC) are emerging as well which need to be integrated into large application ontologies, sometimes by people who do not have much training in knowledge representation. This process has generated needs for tools that support broad ranges of users in (1) merging of ontological terms from varied sources, (2) diagnosis of coverage and correctness of ontologies, and (3) maintaining ontologies over time. In this paper, we present a new merging and diagnostic ontology environment called Chimaera, which was developed to address these issues in the context of HPKB. We also report on some initial tests of its effectiveness in merging tasks.
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paper_title: TAMBIS: transparent access to multiple bioinformatics information sources

paper_content:

UNLABELLED: TAMBIS (Transparent Access to Multiple Bioinformatics Information Sources) is an application that allows biologists to ask rich and complex questions over a range of bioinformatics resources. It is based on a model of the knowledge of the concepts and their relationships in molecular biology and bioinformatics. AVAILABILITY: TAMBIS is available as an applet from http://img.cs.man.ac.uk/tambis SUPPLEMENTARY: A full manual, tutorial and videos can be found at http://img.cs.man.ac.uk/tambis. CONTACT: tambis@cs.man.ac.uk
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paper_title: Some Issues on Ontology Integration

paper_content:

The word integration has been used with different ::: meanings in the ontology field. This article ::: aims at clarifying the meaning of the word “integration” ::: and presenting some of the relevant work ::: done in integration. We identify three meanings of ::: ontology “integration”: when building a new ontology ::: reusing (by assembling, extending, specializing ::: or adapting) other ontologies already available; ::: when building an ontology by merging several ::: ontologies into a single one that unifies all of ::: them; when building an application using one or ::: more ontologies. We discuss the different meanings ::: of “integration”, identify the main characteristics ::: of the three different processes and proposethree words to distinguish among those meanings:integration, merge and use.
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paper_title: BACIIS: Biological and Chemical Information Integration System

paper_content:

Life science Web databases are becoming increasingly essential in conducting everyday biological research. With more than 300 life science Web databases and the growing size of the life science data, searching and managing these complex data requires technology beyond that of traditional database systems. The open research issues include the interoperability of geographically distributed autonomous databases, which are generally only Web-accessible, and the seamless semantic-based integration of these databases with total transparency to the user. In this paper, the implementation of a Biological and Chemical Information Integration System (BACIIS) is presented. BACIIS supports the integration of multiple heterogeneous life science Web databases and allows the execution of global applications that extend beyond the boundaries of individual databases. This paper discusses the architecture of BACIIS. It also discusses the techniques used to extract and integrate data from the various life science Web databases.
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paper_title: Ontology Mapping: The State of the Art

paper_content:

Ontology mapping is seen as a solution provider in today's landscape of ontology research. As the number of ontologies that are made publicly available and accessible on the Web increases steadily, so does the need for applications to use them. A single ontology is no longer enough to support the tasks envisaged by a distributed environment like the Semantic Web. Multiple ontologies need to be accessed from several applications. Mapping could provide a common layer from which several ontologies could be accessed and hence could exchange information in semantically sound manners. Developing such mappings has been the focus of a variety of works originating from diverse communities over a number of years. In this article we comprehensively review and present these works. We also provide insights on the pragmatics of ontology mapping and elaborate on a theoretical approach for defining ontology mapping.
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paper_title: Some Issues on Ontology Integration

paper_content:

The word integration has been used with different ::: meanings in the ontology field. This article ::: aims at clarifying the meaning of the word “integration” ::: and presenting some of the relevant work ::: done in integration. We identify three meanings of ::: ontology “integration”: when building a new ontology ::: reusing (by assembling, extending, specializing ::: or adapting) other ontologies already available; ::: when building an ontology by merging several ::: ontologies into a single one that unifies all of ::: them; when building an application using one or ::: more ontologies. We discuss the different meanings ::: of “integration”, identify the main characteristics ::: of the three different processes and proposethree words to distinguish among those meanings:integration, merge and use.
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Title: Ontology Change: Classification and Survey

Section 1: Introduction
Description 1: Describe the background, importance, and motivation for studying ontology change, and outline the main objectives of the survey.

Section 2: What is an Ontology?
Description 2: Define the term ontology, discuss its various definitions in the literature, and explain its role in AI and the Semantic Web.

Section 3: Ontology Change
Description 3: Explain the concept of ontology change, reasons for ontology change, and the challenges associated with it.

Section 4: Ontology Change Subfields: A Short Discussion
Description 4: Introduce the subfields of ontology change, including ontology mapping, morphism, matching, articulation, translation, evolution, debugging, versioning, integration, and merging. Provide a brief description of each.

Section 5: Discussion on Heterogeneity Resolution
Description 5: Discuss the problem of heterogeneity in ontologies and describe various approaches and algorithms used to resolve it.

Section 6: State of the Art in Heterogeneity Resolution
Description 6: Review current systems and tools for heterogeneity resolution, and discuss their methodologies and effectiveness.

Section 7: Disambiguating the Terms
Description 7: Clarify the terms ontology evolution and versioning, and differentiate between them. Discuss the relationship and distinction between ontology evolution, debugging, and versioning.

Section 8: General Discussion on Ontology Evolution
Description 8: Provide a detailed discussion of ontology evolution processes and phases. Explain how ontology evolution is implemented and validated.

Section 9: State of the Art in Ontology Evolution
Description 9: Review current tools and approaches in ontology evolution, highlighting key methodologies and their effectiveness.

Section 10: Ontology Debugging
Description 10: Define ontology debugging, discuss its importance, and outline approaches and techniques used to identify and resolve logical contradictions in ontologies.

Section 11: Ontology Versioning
Description 11: Explain the concept of ontology versioning, discuss the challenges it faces, and review methodologies and tools developed to manage versioning of ontologies.

Section 12: Definitions and Discussion on Ontology Integration and Merging
Description 12: Define ontology integration and merging, discuss their differences, and review methodologies used in these processes.

Section 13: State of the Art in Ontology Integration and Merging
Description 13: Review current tools and approaches for ontology integration and merging, including their methodologies and effectiveness.

Section 14: Conclusion
Description 14: Summarize the findings of the survey, discuss the significance of ontology change, and suggest directions for future research.