Survey of Context Provisioning Middleware
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paper_title: A Context-Aware Framework for Mobile Navigation Service

paper_content:

As cellular network technologies continue to evolve, various network standards must coexist in most CDMA-based cellular networks. This means that mobile device users access mobile services over different network bandwidths according to the users' positions or the mobile devices' network access capabilities. Such differences of network bandwidths result in considerable differences in service response times. To address this problem, we present CANS (context-aware framework for mobile navigation services), a context-aware framework which takes into account the user's network profile to adapt the content for mobile device-based navigation services. Experimental results show that CANS can provide similar service response times regardless of type of wireless network to which users connect by adapting the content to network bandwidths.
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paper_title: Intelligent Agents Meet Semantic Web in a Smart Meeting Room

paper_content:

We describe a new smart meeting room system called EasyMeeting that explores the use of FIPA agent technologies, Semantic Web ontologies, logic reasoning, and security and privacy policies. Building on a pervasive computing system that we have developed previously, EasyMeeting can provide relevant services and information to meeting participants based on their situational needs. Our system exploits the context-aware support provided by the Context Broker Architecture (CoBrA). Central to CoBrA is an intelligent broker agent that maintains a shared model of context for all computing entities in the space and enforces the privacy policies defined by the users. We also describe the use of CoBrA ontologies, logic reasoning, and privacy protection mechanisms, and evaluate our initial user experience studies.
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paper_title: Smart advertising in the home of the future

paper_content:

With the emergence of smart home environments, services are constantly subject to changes, seeking the customer's full satisfaction. Enriching these services with innovative approaches such as context-aware, mobile, adaptable and interactive mechanisms, enables users to experience a variety of personalised services seamlessly across different platforms and technologies. Moreover, considering advertising as the enabler for next generation services, it is important to explore its integration into new domains. This paper, therefore presents a framework approach to address advertising solutions focusing on smart home environments, enriching the overall user quality of experience. In addition, by over viewing the current smart homes market scenario, it provides the vision to overcome the established advertising paradigms focusing on key points like user privacy protection, online social networks and reality mining technologies.
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paper_title: Understanding and Using Context

paper_content:

A device for detaching a sheet-shaped copy support from a moving photoconductive layer by fluid pressure. The device includes a nozzle arrangement which directs pressurized fluid, such as compressed air, toward a sheet of copy paper or other copy support. The action of the fluid on the copy support creates a suction pressure which draws the copy support toward the nozzle arrangement to detach the copy support from the photoconductive layer. When the copy support has moved into close proximity and generally overlying relationship with respect to the nozzle arrangement, the fluid is passed off generally tangentially with respect to the copy support to maintain a constant suction and to avoid undesirable oscillations of the copy support. This, in turn, eliminates the undesirable noise associated with such oscillations.
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paper_title: Automatic Identification of Informal Social Groups and Places for Geo-Social Recommendations

paper_content:

Mobile locatable devices can help identify previously unknown ad hoc or semi-permanent groups of people and their meeting places. Newly identified groups or places can be recommended to people to enhance their geo-social experience, while respecting privacy constraints. For instance, new students can learn about popular hangouts on campus or faculty members can learn about groups of students routinely having research discussions. This paper presents a clustering algorithm based on user copresence that identifies such groups and places even when group members participate to only a certain fraction of meetings. Simulation results demonstrate that 90 96% of group members can be identified with negligible false positives when the user meeting attendance is at least 50%. Experimental results using one-month of mobility traces collected from smart phones running Intel's PlaceLab location engine successfully identified all groups that met regularly during that period. Additionally, the group places were identified with good accuracy.
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paper_title: Special Issue on Ubiquitous Games

paper_content:

Computer games have grown during recent years into a popular entertainment form with a wide variety of game types and a large consumer group spread across the world. An increasing number of people are playing electronic games, placing them among other favorite leisure activities. When surveyed on the most fun entertainment activities in the year 2000, 35 percent of all Americans identified computer and video games, where watching television fell second at 18 percent, followed by surfing the internet (15%), reading books (13 %) and going to the movies (11%) [8]. On-line gaming has offered people new means of having social interaction with people in faraway locations and let them access and play out fantasy-driven identities they are unable to manifest in the real world [12]. In 2002, the percentage of frequent game players that play games online rose to 31 percent up from 24 percent the year before [8]. Within the games, or through the use of websites based around the games, dedicated and long-lived communities have formed which have created new content, sometimes leading to commercial ventures. Electronic game play, however, is not limited to home use. Game parlors and LAN parties are becoming a popular means to play online games. Also, 37 percent of Americans who own game consoles (or computers used to play games), report that they also play games on mobile devices such as PDAs and mobile phones [8]. The popularity of computer games has thus not only made them important carriers of culture and trends but also a financially interesting area. They also function as a vehicle for the development and deployment of new hardware, software and user interface techniques. According to Interactive Digital Software Association (www.idsa.com), the computer and video game software industry in the US generated $6.35 billon in sales from 225 million units in 2001 (up 7.9% and 4.5% from 2000 respectively). In the same year in the US, movie box office grosses were $8.41 billion [8]. In the UK in the year 2000, the entertainment software industries grossed £300 million more than the UK cinema box offices and almost double that of home video rentals [3]. The world entertainment software market is estimated to be almost $18 billion and to grow to $26.7 billion by the year 2005 [3]. Computer games are some of the applications available to the general public that have the very highest demands on ease-of-use, engagement, and aesthetical appearance. These demands have made developers of computer games use the latest techniques within artificial intelligence, multimedia, computer graphics, computer simulation, and human-computer interaction to be competitive against other games developers. For example, recently IBM, Sony, and Toshiba have partnered on creation of the ‘Cell’. The Cell is a unique type of computer processor that contains several types of computing cores that are optimized for one type of task (e.g. communications, video processing). These processing cells can be interconnected to optimize a specific task [11]. This exciting research has not been driven for use in supercomputers, or high-end business PCs, but for use in the Playstation, a gaming console.
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paper_title: Toward interactive mobile synchronous learning environment with context-awareness service

paper_content:

Mobile synchronous learning is a new challenge in the e-learning domain. While popular mobile communication devices, such as cell phones, cannot directly accommodate traditional synchronous content due to the major limitation of display size, other constraints also restrict convenient interactions while using mobile devices in a synchronous learning environment. These problems have motivated the authors of this study to design a context-awareness synchronous learning system and to develop a corresponding pedagogical framework. Different than existing synchronous learning strategies, the proposed system enhances the feedback mechanism and implements an enhanced model for achieving mobile interaction in a synchronous learning environment. The enhanced model is named Interactive Service Module, which enables interactions between teachers and students via short message delivery. In the proposed synchronous learning environment, different kinds of learning devices are used to access the same source of synchronous content simultaneously. To accommodate the diversity of devices, several content styles have been developed and an appropriate style can be selected to a learner via a decision mechanism. This mechanism is based on fuzzy weighted average technique to measure the average computational power for each device. Finally, questionnaires were used to evaluate the usability of the proposed synchronous learning environment, and the results indicate that our system can facilitate synchronous learning by enabling students to access lessons conveniently and efficiently from a wide variety of locations, using common mobile communication devices.
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paper_title: Reasoning with Contextual Data in Telehealth Applications

paper_content:

The notion of context-awareness is making its way in the area of mobile-health application designed to assist patients outside a hospital and medical professionals within a hospital. Such ubiquitous computing applications go beyond simple biomedical data-collection so the management of the context becomes more challenging, and the complexity of the context-based decision-algorithms warrants the use of full-blown inference engines. The context is a very volatile notion, so building a context-aware system means more than just creating a context ontology and defining inference rules for that model. This paper proposes mechanisms to dynamically manage the contextual decisions and actions. It devises a model and its properties for the process of taking each individual context-based decision. An architecture centered around this model is defined, integrating an off-the-shelf inference engine that reasons on context-data expressed in the OWL language. The architecture was refined and validated through the implementation of a prototype remote biomonitoring system. The prototype combines context-adaptation and awareness with the ubiquity of 3G network-coverage to allow for more personalized monitoring and better streamlining of information between the various health care players. It can be easily adapted and extended with extra inference-rules, additional actions, and more context items.
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paper_title: Extraction of social context and application to personal multimedia exploration

paper_content:

Personal media collections are often viewed and managed along the social dimension, the places we spend time at and the people we see, thus tools for extracting and using this information are required. We present novel algorithms for identifying socially significant places termed social spheres unobtrusively from GPS traces of daily life, and label them as one of Home, Work, or Other, with quantitative evaluation of 9 months taken from 5 users. We extract locational co-presence of these users and formulate a novel measure of social tie strength based on frequency of interaction, and the nature of spheres it occurs within. Comparative user studies of a multimedia browser designed to demonstrate the utility of social metadata indicate the usefulness of a simple interface allowing navigation and filtering in these terms. We note the application of social context is potentially much broader than personal media management, including context-aware device behaviour, life logs, social networks, and location-aware information services.
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paper_title: The invisible future: the seamless integration of technology into everyday life

paper_content:

Funding the future - the third wave of the computing revolution flesh and machines don't count society out the rise and fall of Turing-Church's thesis moving design to the other side of the screen one is glad to be of service a compass for computing's future an IT profession the unfinished revolution in design lifestreams at the interface the end of career somatics in cyberspace will computer programs write beautiful music? free market electrical network management engineering in the future depends on future engineers the computer revolution hasn't happened yet why we will spend most of our time in virtual reality in the 21st century beyond Jules Verne - ocean exploration for the 21st century life after Internet ambient intelligence when our environment becomes really smart science's endless golden age.
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paper_title: Understanding and Using Context

paper_content:

A device for detaching a sheet-shaped copy support from a moving photoconductive layer by fluid pressure. The device includes a nozzle arrangement which directs pressurized fluid, such as compressed air, toward a sheet of copy paper or other copy support. The action of the fluid on the copy support creates a suction pressure which draws the copy support toward the nozzle arrangement to detach the copy support from the photoconductive layer. When the copy support has moved into close proximity and generally overlying relationship with respect to the nozzle arrangement, the fluid is passed off generally tangentially with respect to the copy support to maintain a constant suction and to avoid undesirable oscillations of the copy support. This, in turn, eliminates the undesirable noise associated with such oscillations.
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paper_title: Inferring intentions in generic context-aware systems

paper_content:

Many context-aware projects try to develop the next step in human computer interaction, systems that adapt to a users need and help him to focus on his specific task. Probabilistic models are used to infer the current activity of a user. These techniques for predicting the actions of a user are often custom-tailored to a fixed location and scenario. We developed a method to generate probabilistic models for different context, therefore broaden their use in different domains of ubiquitous computing. This makes our intention analysis more generic.
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paper_title: A survey of autonomic communications

paper_content:

Autonomic communications seek to improve the ability of network and services to cope with unpredicted change, including changes in topology, load, task, the physical and logical characteristics of the networks that can be accessed, and so forth. Broad-ranging autonomic solutions require designers to account for a range of end-to-end issues affecting programming models, network and contextual modeling and reasoning, decentralised algorithms, trust acquisition and maintenance---issues whose solutions may draw on approaches and results from a surprisingly broad range of disciplines. We survey the current state of autonomic communications research and identify significant emerging trends and techniques.
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paper_title: Disseminating active map information to mobile hosts

paper_content:

The article describes an active map service (AMS) that supports context-aware computing by providing clients with information about located-objects and how those objects change over time. The authors focus on the communication issues of disseminating information from an active map server to its clients, and in particular, address how to deal with various overload situations that can occur. Simple unicast callbacks to interested clients work well enough if only a few located-objects are moving at any given time and only a few clients wish to know about any given move. However, if many people are moving about in the same region and many clients are interested in their motion, then the AMS may experience overload due to the quadratic nature of the communications involved. This overload affects both the server as well as any slow communications links being used. Mobile distributed computing enables users to interact with many different mobile and stationary computers over the course of the day. Navigating a mobile environment can be aided by active maps that describe the location and characteristics of objects within some region as they change over time. >
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paper_title: A Context Modeling Survey

paper_content:

Context-awareness is one of the drivers of the ubiquitous computing paradigm, whereas a well designed model is a key accessor to the context in any context-aware system. This paper provides a survey of the the most relevant current approaches to modeling context for ubiquitous computing. Numerous approaches are reviewed, classified relative to their core elements and evaluated with respect to their appropriateness for ubiquitous computing.
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paper_title: A Survey of Context Modelling and Reasoning Techniques

paper_content:

Development of context-aware applications is inherently complex. These applications adapt to changing context information: physical context, computational context, and user context/tasks. Context information is gathered from a variety of sources that differ in the quality of information they produce and that are often failure prone. The pervasive computing community increasingly understands that developing context-aware applications should be supported by adequate context information modelling and reasoning techniques. These techniques reduce the complexity of context-aware applications and improve their maintainability and evolvability. In this paper we discuss the requirements that context modelling and reasoning techniques should meet, including the modelling of a variety of context information types and their relationships, of situations as abstractions of context information facts, of histories of context information, and of uncertainty of context information. This discussion is followed by a description and comparison of current context modelling and reasoning techniques.
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paper_title: Ontology based context modeling and reasoning using OWL

paper_content:

Here we propose an OWL encoded context ontology (CONON) for modeling context in pervasive computing environments, and for supporting logic-based context reasoning. CONON provides an upper context ontology that captures general concepts about basic context, and also provides extensibility for adding domain-specific ontology in a hierarchical manner. Based on this context ontology, we have studied the use of logic reasoning to check the consistency of context information, and to reason over low-level, explicit context to derive high-level, implicit context. By giving a performance study for our prototype, we quantitatively evaluate the feasibility of logic based context reasoning for nontime-critical applications in pervasive computing environments, where we always have to deal carefully with the limitation of computational resources.
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paper_title: An artificial chemistry based framework for personal and social context aware smart spaces

paper_content:

Supporting context-aware services and applications that are delivered to a user as they move through a smart space is a challenge. The complexity of awareness and interaction requires an efficient interaction and adaptation model. Most research prototypes comprise of many models and extensive middleware which seems excessive for simple context-aware applications involving pervasive devices. Part of the problem is finding a conceptual abstraction which is compact and concise yet can exclusively model all the dynamism and expressivity required for such a system. In this paper we propose a context aware architecture based on a smart space context model and a middleware inspired by chemical reactions.
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paper_title: A software engineering framework for context-aware pervasive computing

paper_content:

There is growing interest in the use of context-awareness as a technique for developing pervasive computing applications that are flexible, adaptable, and capable of acting autonomously on behalf of users. However, context-awareness introduces various software engineering challenges, as well as privacy and usability concerns. In this paper, we present a conceptual framework and software infrastructure that together address known software engineering challenges, and enable further practical exploration of social and usability issues by facilitating the prototyping and fine-tuning of context-aware applications.
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paper_title: ContextML: A light-weight context representation and context management schema

paper_content:

Context representation is a fundamental process in developing context aware systems for the pervasive world. We present a light weight XML based context representation schema called ContextML in which context information is categorized into scopes and related to different types of entities (e.g. user, device). The schema is also applied for encoding management messages in order to allow for a flexible framework supporting gradual plug & play extendibility and mobility. ContextML is tailored to be used for REST-based communication between the framework components. Explanation of the schema is provided with the help of real world examples. Moreover, the European C-CAST testbed is introduced, embracing a variety of context providers and application domains.
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paper_title: OWL Web Ontology Language - Reference

paper_content:

The {W}eb {O}ntology {L}anguage {OWL} is a semantic markup language for publishing and sharing ontologies on the {W}orld {W}ide {W}eb. {OWL} is developed as a vocabulary extension of {RDF} (the {R}esource {D}escription {F}ramework) and is derived from the {DAML}+{OIL} {W}eb {O}ntology {L}anguage. {T}his document contains a structured informal description of the full set of {OWL} language constructs and is meant to serve as a reference for {OWL} users who want to construct {OWL} ontologies.
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paper_title: Context-awareness on mobile devices - the hydrogen approach

paper_content:

Information about the user's environment offers new opportunities and exposes new challenges in terms of time-aware, location-aware, device-aware and personalized applications. Such applications constantly need to monitor the environment - called context - to allow the application to react accordingly to this context. Context-awareness is especially interesting in mobile scenarios where the context of the application is highly dynamic and allows the application to deal with the constraints of mobile devices in terms of presentation and interaction abilities and communication restrictions. Current context-aware applications often realize sensing of context information in an ad hoc manner. The application programmer needs to deal with the supply of the context information including the sensing of the environment, its interpretation and its disposal for further processing in addition to the primary purpose of the application. The close interweavement of device specific context handling with the application obstructs its reuse with other hardware configurations. Recently, architectures providing support for context-aware applications have been developed. Up to now such architectures are not trimmed to the special requirements of mobile devices regarding particularly the limitations of network connections, limited computing power and the characteristics of mobile users. This paper proposes an architecture and a software framework - the hydrogen context framework -which support context-awareness for considering these constraints. It is extensible to consider all kind of context information and comprises a layered architecture. To prove the feasibility the framework has been implemented to run on mobile devices. A context-aware postbox is realized to demonstrate the capabilities of the framework.
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paper_title: A data-oriented survey of context models

paper_content:

Context-aware systems are pervading everyday life, therefore context modeling is becoming a relevant issue and an expanding research field. This survey has the goal to provide a comprehensive evaluation framework, allowing application designers to compare context models with respect to a given target application; in particular we stress the analysis of those features which are relevant for the problem of data tailoring. The contribution of this paper is twofold: a general analysis framework for context models and an up-to-date comparison of the most interesting, data-oriented approaches available in the literature.
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paper_title: ContextUML: a UML-based modeling language for model-driven development of context-aware Web services

paper_content:

Context-aware Web services are emerging as a promising technology for the electronic businesses in mobile and pervasive environments. Unfortunately, complex context-aware services are still hard to build. In this paper, we present a modeling language for the model-driven development of context-aware Web services based on the Unified Modeling Language (UML). Specifically, we show how UML can be used to specify information related to the design of context-aware services. We present the abstract syntax and notation of the language and illustrate its usage using an example service. Our language offers significant design flexibility that considerably simplifies the development of context-aware Web services.
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paper_title: A Survey on Context-aware systems

paper_content:

Context-aware systems offer entirely new opportunities for application developers and for end users by gathering context data and adapting systems behaviour accordingly. Especially in combination with mobile devices, these mechanisms are of high value and are used to increase usability tremendously. In this paper, we present common architecture principles of context-aware systems and derive a layered conceptual design framework to explain the different elements common to most context-aware architectures. Based on these design principles, we introduce various existing context-aware systems focusing on context-aware middleware and frameworks, which ease the development of context-aware applications. We discuss various approaches and analyse important aspects in context-aware computing on the basis of the presented systems.
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paper_title: An ontology for mobile device sensor-based context awareness

paper_content:

In mobile computing, the efficient utilisation of the information gained from the sensors embedded in the devices is difficult. Instead of using raw measurement data application specifically, as currently is customary, higher abstraction level semantic descriptions of the situation, context, can be used to develop mobile applications that are more usable. This article introduces an ontology of context constituents, which are derived from a set of sensors embedded in a mobile device. In other words, a semantic interface to the sensor data is provided. The ontology promotes the rapid development of mobile applications, more efficient use of resources, as well as reuse and sharing of information between communicating entities. A few mobile applications are presented to illustrate the possibilities of using the ontology.
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paper_title: ContextML: A light-weight context representation and context management schema

paper_content:

Context representation is a fundamental process in developing context aware systems for the pervasive world. We present a light weight XML based context representation schema called ContextML in which context information is categorized into scopes and related to different types of entities (e.g. user, device). The schema is also applied for encoding management messages in order to allow for a flexible framework supporting gradual plug & play extendibility and mobility. ContextML is tailored to be used for REST-based communication between the framework components. Explanation of the schema is provided with the help of real world examples. Moreover, the European C-CAST testbed is introduced, embracing a variety of context providers and application domains.
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paper_title: Context-aware systems: A literature review and classification

paper_content:

Nowadays, numerous journals and conferences have published articles related to context-aware systems, indicating many researchers' interest. Therefore, the goal of this paper is to review the works that were published in journals, suggest a new classification framework of context-aware systems, and explore each feature of classification framework. This paper is based on a literature review of context-aware systems from 2000 to 2007 using a keyword index and article title search. The classification framework is developed based on the architecture of context-aware systems, which consists of the following five layers: concept and research layer, network layer, middleware layer, application layer and user infrastructure layer. The articles are categorized based on the classification framework. This paper allows researchers to extract several lessons learned that are important for the implementation of context-aware systems.
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paper_title: A Survey on Context-aware systems

paper_content:

Context-aware systems offer entirely new opportunities for application developers and for end users by gathering context data and adapting systems behaviour accordingly. Especially in combination with mobile devices, these mechanisms are of high value and are used to increase usability tremendously. In this paper, we present common architecture principles of context-aware systems and derive a layered conceptual design framework to explain the different elements common to most context-aware architectures. Based on these design principles, we introduce various existing context-aware systems focusing on context-aware middleware and frameworks, which ease the development of context-aware applications. We discuss various approaches and analyse important aspects in context-aware computing on the basis of the presented systems.
---
paper_title: Context-aware systems: A literature review and classification

paper_content:

Nowadays, numerous journals and conferences have published articles related to context-aware systems, indicating many researchers' interest. Therefore, the goal of this paper is to review the works that were published in journals, suggest a new classification framework of context-aware systems, and explore each feature of classification framework. This paper is based on a literature review of context-aware systems from 2000 to 2007 using a keyword index and article title search. The classification framework is developed based on the architecture of context-aware systems, which consists of the following five layers: concept and research layer, network layer, middleware layer, application layer and user infrastructure layer. The articles are categorized based on the classification framework. This paper allows researchers to extract several lessons learned that are important for the implementation of context-aware systems.
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paper_title: Architectures for Context

paper_content:

The development of context-aware applications will require tools that are based on clearly defined models of context and system software architecture. This essay introduces models for each of these, examines the tradeoffs among the different alternatives, and describes a blackboard-based context architecture that is being used in the construction of interactive workspaces.
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paper_title: A Survey on Context-aware systems

paper_content:

Context-aware systems offer entirely new opportunities for application developers and for end users by gathering context data and adapting systems behaviour accordingly. Especially in combination with mobile devices, these mechanisms are of high value and are used to increase usability tremendously. In this paper, we present common architecture principles of context-aware systems and derive a layered conceptual design framework to explain the different elements common to most context-aware architectures. Based on these design principles, we introduce various existing context-aware systems focusing on context-aware middleware and frameworks, which ease the development of context-aware applications. We discuss various approaches and analyse important aspects in context-aware computing on the basis of the presented systems.
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paper_title: A Survey on Context-Aware Mobile and Wireless Networking: On Networking and Computing Environments' Integration

paper_content:

During the last years, a continuous convergence and fusion of computing and networking systems is stressed in the ICT research community. Context awareness appears to be a major research "glue-point" of such kind of heterogeneous environments' integration. In this survey paper, we aim to assemble all the "puzzle-pieces" of the emerging research area of Context Aware Mobile and Wireless Networking (CAMoWiN) in order to provide the reader a holistic representation of the work having been done in the past emphasizing in recent research efforts. A precise definition of abstract Context Aware (CA) functionalities together with a clear classification of related state-of-the-art proposals are provided in the form of a proposed taxonomy scheme per CA functionality. Each taxonomy scheme can also serve as a sufficiently general framework permitting the easy classification of novel CAMoWiN solutions emerging in the near future. Therefore, our study not only defines all the possible components of a CAMoWiN architecture and clearly points out the similarities and differences of all research efforts in the field but also evaluates future research trends and paves the way for the researchers to work beyond the concepts investigated in this work. Finally, apart from identifying the open challenges, which arise when applying traditional concepts of pervasive computing to mobile and wireless networks, we further map them to the Mobile Cloud Computing paradigm, whose concepts appear to be very promising regarding next generation networking and computing environments' integration.
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paper_title: The Java Context Awareness Framework (JCAF) - A Service Infrastructure and Programming Framework for Context-Aware Applications

paper_content:

Context-awareness is a key concept in ubiquitous computing. But to avoid developing dedicated context-awareness sub-systems for specific application areas there is a need for more generic programming frameworks. Such frameworks can help the programmer develop and deploy context-aware applications faster. This paper describes the Java Context-Awareness Framework – JCAF, which is a Java-based context-awareness infrastructure and programming API for creating context-aware computer applications. The paper presents the design goals of JCAF, its runtime architecture, and its programming model. The paper presents some applications of using JCAF in three different applications and discusses lessons learned from using JCAF.
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paper_title: A service-oriented middleware for building context-aware

paper_content:

The advancement of wireless networks and mobile computing necessitates more advanced applications and services to be built with context-awareness enabled and adaptability to their changing contexts. Today, building context-aware services is a complex task due to the lack of an adequate infrastructure support in pervasive computing environments. In this article, we propose a Service-Oriented Context-Aware Middleware (SOCAM) architecture for the building and rapid prototyping of context-aware services. It provides efficient support for acquiring, discovering, interpreting and accessing various contexts to build context-aware services. We also propose a formal context model based on ontology using Web Ontology Language to address issues including semantic representation, context reasoning, context classification and dependency. We describe our context model and the middleware architecture, and present a performance study for our prototype in a smart home environment.
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paper_title: A context-aware middleware for applications in mobile Ad Hoc environments

paper_content:

Novel ubiquitous computing applications such as intelligent vehicles, smart buildings, and traffic management require special properties that traditional computing applications do not support, such as context-awareness, massive decentralisation, autonomous behaviour, adaptivity, proactivity, and innate collaboration. This paper presents a new computational model and middleware that reflect support for the required the properties. The sentient object model is proposed by the CORTEX1 project to support the construction of ubiquitous applications. A flexible, run-time reconfigurable component-based middleware has been built to provide run-time support to engineer the sentient object programming paradigm. An application infrastructure using sentient objects to enable cooperation between autonomous and proactive vehicles has been implemented to demonstrate the appropriateness of the computational model and the validity of the middleware for pervasive mobile ad hoc computing.
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paper_title: The Java Context Awareness Framework (JCAF) - A Service Infrastructure and Programming Framework for Context-Aware Applications

paper_content:

Context-awareness is a key concept in ubiquitous computing. But to avoid developing dedicated context-awareness sub-systems for specific application areas there is a need for more generic programming frameworks. Such frameworks can help the programmer develop and deploy context-aware applications faster. This paper describes the Java Context-Awareness Framework – JCAF, which is a Java-based context-awareness infrastructure and programming API for creating context-aware computer applications. The paper presents the design goals of JCAF, its runtime architecture, and its programming model. The paper presents some applications of using JCAF in three different applications and discusses lessons learned from using JCAF.
---
paper_title: Context-awareness on mobile devices - the hydrogen approach

paper_content:

Information about the user's environment offers new opportunities and exposes new challenges in terms of time-aware, location-aware, device-aware and personalized applications. Such applications constantly need to monitor the environment - called context - to allow the application to react accordingly to this context. Context-awareness is especially interesting in mobile scenarios where the context of the application is highly dynamic and allows the application to deal with the constraints of mobile devices in terms of presentation and interaction abilities and communication restrictions. Current context-aware applications often realize sensing of context information in an ad hoc manner. The application programmer needs to deal with the supply of the context information including the sensing of the environment, its interpretation and its disposal for further processing in addition to the primary purpose of the application. The close interweavement of device specific context handling with the application obstructs its reuse with other hardware configurations. Recently, architectures providing support for context-aware applications have been developed. Up to now such architectures are not trimmed to the special requirements of mobile devices regarding particularly the limitations of network connections, limited computing power and the characteristics of mobile users. This paper proposes an architecture and a software framework - the hydrogen context framework -which support context-awareness for considering these constraints. It is extensible to consider all kind of context information and comprises a layered architecture. To prove the feasibility the framework has been implemented to run on mobile devices. A context-aware postbox is realized to demonstrate the capabilities of the framework.
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paper_title: An Architecture to Support Context-Aware Applications

paper_content:

Context is an important, yet poorly utilized source of information in interactive computing. It is difficult to use because, unlike other forms of user input, there is no common, reusable way to handle context. Most contextaware applications have been built in an ad hoc manner. We discuss the requirements for dealing with context and present an architectural solution we have designed and implemented to help application designers build contextaware applications more easily. We illustrate the use of the architecture through a context-aware application that assists conference attendees.
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paper_title: A context-aware middleware for applications in mobile Ad Hoc environments

paper_content:

Novel ubiquitous computing applications such as intelligent vehicles, smart buildings, and traffic management require special properties that traditional computing applications do not support, such as context-awareness, massive decentralisation, autonomous behaviour, adaptivity, proactivity, and innate collaboration. This paper presents a new computational model and middleware that reflect support for the required the properties. The sentient object model is proposed by the CORTEX1 project to support the construction of ubiquitous applications. A flexible, run-time reconfigurable component-based middleware has been built to provide run-time support to engineer the sentient object programming paradigm. An application infrastructure using sentient objects to enable cooperation between autonomous and proactive vehicles has been implemented to demonstrate the appropriateness of the computational model and the validity of the middleware for pervasive mobile ad hoc computing.
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paper_title: EgoSpaces: facilitating rapid development of context-aware mobile applications

paper_content:

Today's mobile applications require constant adaptation to their changing environments, or contexts. Technological advances have increased the pervasiveness of mobile computing devices such as laptops, handhelds, and embedded sensors. The sheer amount of context information available for adaptation places a heightened burden on application developers as they must manage and utilize vast amounts of data from diverse sources. Facilitating programming in this data-rich environment requires a middleware that provides context information to applications in an abstract form. In this paper, we demonstrate the feasibility of such a middleware that allows programmers to focus on high-level interactions among programs and to employ declarative abstract context specifications in settings that exhibit transient interactions with opportunistically encountered components. We also discuss the novel context-aware abstractions the middleware provides and the programming knowledge necessary to write applications using it. Finally, we provide examples demonstrating the infrastructure's ability to support differing tasks from a wide variety of application domains
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paper_title: Ubiquitous Provision of Context Aware Web Services

paper_content:

Context-aware Web service is an interactive model between the context of service requesters and the services in Web-enabled environments. We envision that providing context-aware services is the first step toward ubiquitous Web services to enhance current Web-based e-business by finding right business partners, right business information, and right business services in the right place at the right time. The major contributions of this paper are the development of our context model and Context Aware Service Oriented Architecture (CA-SOA). We have developed a context model to formally describe and acquire contextual information pertaining to the service requesters and services. Based on the model, we have constructed CA-SOA for ubiquitous Web service discovery and access based on service and requesters? surrounding context.
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paper_title: The Java Context Awareness Framework (JCAF) - A Service Infrastructure and Programming Framework for Context-Aware Applications

paper_content:

Context-awareness is a key concept in ubiquitous computing. But to avoid developing dedicated context-awareness sub-systems for specific application areas there is a need for more generic programming frameworks. Such frameworks can help the programmer develop and deploy context-aware applications faster. This paper describes the Java Context-Awareness Framework – JCAF, which is a Java-based context-awareness infrastructure and programming API for creating context-aware computer applications. The paper presents the design goals of JCAF, its runtime architecture, and its programming model. The paper presents some applications of using JCAF in three different applications and discusses lessons learned from using JCAF.
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paper_title: An Ontology for Context-Aware Pervasive Computing Environments

paper_content:

This document describes COBRA-ONT, an ontology for supporting pervasive context-aware systems. COBRA-ONT, expressed in the Web Ontology Language OWL, is a collection of ontologies for describing places, agents and events and their associated properties in an intelligent meeting-room domain. This ontology is developed as a part of the Context Broker Architecture (CoBrA), a broker-centric agent architecture that provides knowledge sharing, context reasoning and privacy protection supports for pervasive context-aware systems. We also describe an inference engine for reasoning with information expressed using the COBRA-ONT ontology and the ongoing research in using the DAML-Time ontology for context reasoning.
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paper_title: A context-aware system based on service-oriented architecture

paper_content:

Advances in mobile devices, sensors and wireless networks have motivated the development of context-aware applications. Such mobile applications use sensors for monitoring several features such as: location, temperature, velocity, weather, traffic jam, noise, air pollution, and so on. This monitoring enables service provision according to a given context. These applications are known as context-aware systems. Context-aware applications are sensible to user necessities, personalized according to his profile, requirements and context. They evaluate user environment and push information that is relevant to user context. In this paper we present Omnipresent, which is a service-oriented architecture for context-aware applications. Omnipresent may be accessed from either mobile devices or Web browsers, and it is based on Web services and well-established standards for LBS applications such as those proposed by the OpenGeoSpatial Consortium. Omnipresent offers several services: map presentation, routing, advertisement, and also works as a reminder tool.
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paper_title: A service-oriented middleware for building context-aware

paper_content:

The advancement of wireless networks and mobile computing necessitates more advanced applications and services to be built with context-awareness enabled and adaptability to their changing contexts. Today, building context-aware services is a complex task due to the lack of an adequate infrastructure support in pervasive computing environments. In this article, we propose a Service-Oriented Context-Aware Middleware (SOCAM) architecture for the building and rapid prototyping of context-aware services. It provides efficient support for acquiring, discovering, interpreting and accessing various contexts to build context-aware services. We also propose a formal context model based on ontology using Web Ontology Language to address issues including semantic representation, context reasoning, context classification and dependency. We describe our context model and the middleware architecture, and present a performance study for our prototype in a smart home environment.
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paper_title: An OSGi-based infrastructure for context-aware multimedia services

paper_content:

This article proposes an OSGi-based infrastructure for context-aware multimedia services in a smart home environment. A context-aware multimedia middleware (CMM), which supports multimedia content filtering, recommendation, and adaptation according to changing context is presented. It also performs context aggregation, reasoning, and learning. To foster device and service interoperability, CMM is integrated with an OSGi service platform. We envisage the OSGi-based infrastructure to fill the niche of three gateways in a smart home: network connecting, context provisioning, and multimedia personalizing
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paper_title: Toward an OSGi-based infrastructure for context-aware applications

paper_content:

Applications and services must adapt to changing contexts in dynamic environments. However, building context-aware applications is still complex and time-consuming due to inadequate infrastructure support. We propose a context-aware infrastructure for building and rapidly prototyping such applications in a smart-home environment. This OSGi-based infrastructure manages context-aware services reliably and securely and efficiently supports context acquisition, discovery, and reasoning. A formal, ontology-based context model enables semantic context representation, reasoning, and knowledge sharing. We propose an ontology-based context model that leverages Semantic Web technology and OWL (Web Ontology Language). OWL is an ontology markup language that enables context sharing and context reasoning. Based on our context model, we also propose a service-oriented context-aware middleware (SOCAM) architecture, including a set of independent services that perform context discovery, acquisition, and interpretation.
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paper_title: Cooperative Multiagent Systems: A Personal View of the State of the Art

paper_content:

Scientific research and practice in multiagent systems focuses on constructing computational frameworks, principles, and models for how both small and large societies of intelligent, semiautonomous agents can interact effectively to achieve their goals. This article provides a personal view of the key application areas for cooperative multiagent systems, the major intellectual problems in building such systems, the underlying principles governing their design, and the major directions and challenges for future developments in this field.
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paper_title: A Middleware Infrastructure for Active Spaces

paper_content:

The paper discusses the Gaia metaoperating system which extends the reach of traditional operating systems to manage ubiquitous computing habitats and living spaces as integrated programmable environments. Gaia exports services to query, access, and use existing resources and context, and provides a framework to develop user-centric, resource-aware, multidevice, context-sensitive, and mobile applications.
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paper_title: Escape - an adaptive framework for managing and providing context information in emergency situations

paper_content:

Supporting adaptive processes in tackling emergency situations, such as disasters, is a key issue for any emergency management system. In such situations, various teams are deployed in many sites, at the front-end or back-end of the situations, to conduct tasks handling the emergency. Context information is of paramount importance in assisting the adaptation of these tasks. However, there is a lack of middleware supporting the management of context information in emergency situations. This paper presents a novel framework that manages and provides various types of context information required for adapting processes in emergency management systems.
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paper_title: inContext: A Pervasive and Collaborative Working Environment for Emerging Team Forms

paper_content:

Participants in current team collaborations belong to different organizations, work on multiple objectives at the same time, and frequently change locations. They use different devices and infrastructures in collaboration processes that can last from a few hours to several years. All these factors pose new challenges to the development of collaborative working environments (CWEs). Existing CWEs are unable to support emerging teams because diverse collaboration services are not well integrated or adapting to the team context. We present the inContext approach to providing a novel pervasive CWE infrastructure for emerging team forms. inContext aggregates disparate collaboration services using Web services and Semantic Web technologies and provides a platform that captures diverse dynamic aspects of team collaborations. By utilizing runtime and historical context and interaction information, adaptation techniques can be deployed to cope with the changes of emerging teams.
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paper_title: A software engineering framework for context-aware pervasive computing

paper_content:

There is growing interest in the use of context-awareness as a technique for developing pervasive computing applications that are flexible, adaptable, and capable of acting autonomously on behalf of users. However, context-awareness introduces various software engineering challenges, as well as privacy and usability concerns. In this paper, we present a conceptual framework and software infrastructure that together address known software engineering challenges, and enable further practical exploration of social and usability issues by facilitating the prototyping and fine-tuning of context-aware applications.
---
paper_title: The Java Context Awareness Framework (JCAF) - A Service Infrastructure and Programming Framework for Context-Aware Applications

paper_content:

Context-awareness is a key concept in ubiquitous computing. But to avoid developing dedicated context-awareness sub-systems for specific application areas there is a need for more generic programming frameworks. Such frameworks can help the programmer develop and deploy context-aware applications faster. This paper describes the Java Context-Awareness Framework – JCAF, which is a Java-based context-awareness infrastructure and programming API for creating context-aware computer applications. The paper presents the design goals of JCAF, its runtime architecture, and its programming model. The paper presents some applications of using JCAF in three different applications and discusses lessons learned from using JCAF.
---
paper_title: Toward a cooperative programming framework for context-aware applications

paper_content:

OPEN is an ontology-based programming framework for rapid prototyping, sharing, and personalization of context-aware applications. Unlike previous systems that provide programming support for single group of users, OPEN provides different programming support for users with diverse technical skills. According to the programming requirements of different users, several cooperation patterns are identified, and the mechanisms to facilitate resource sharing and reuse are built into the framework. Three corresponding programming modes are elaborated by showing how a context-aware game has been developed with the support of the OPEN framework, and the usability of our system is validated through an initial user study.
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paper_title: CASS – a middleware for mobile context-aware applications

paper_content:

Among the difficulties faced by designers of mobile context-aware applications is the increased burden of having to deal with context and also the processing and memory constraints of small mobile computers. Although progress has been made in the area of frameworks and toolkits for contextawareness, there is still a need for middleware that supports higher-level context abstractions and is both flexible and extensible in its treatment of
---
paper_title: A service-oriented middleware for building context-aware

paper_content:

The advancement of wireless networks and mobile computing necessitates more advanced applications and services to be built with context-awareness enabled and adaptability to their changing contexts. Today, building context-aware services is a complex task due to the lack of an adequate infrastructure support in pervasive computing environments. In this article, we propose a Service-Oriented Context-Aware Middleware (SOCAM) architecture for the building and rapid prototyping of context-aware services. It provides efficient support for acquiring, discovering, interpreting and accessing various contexts to build context-aware services. We also propose a formal context model based on ontology using Web Ontology Language to address issues including semantic representation, context reasoning, context classification and dependency. We describe our context model and the middleware architecture, and present a performance study for our prototype in a smart home environment.
---
paper_title: The active badge location system

paper_content:

A novel system for the location of people in an office environment is described. Members of staff wear badges that transmit signals providing information about their location to a centralized location service, through a network of sensors. The paper also examines alternative location techniques, system design issues and applications, particularly relating to telephone call routing. Location systems raise concerns about the privacy of an individual and these issues are also addressed.
---
paper_title: An Intelligent Broker Architecture for Pervasive Context-Aware Systems

paper_content:

Context-aware systems exploit the use of situational information, or context, to provide relevant information and services to users. A great challenge remains in defining an architecture that supports context-aware systems. Critical research issues include modeling and reasoning (how to represent contextual information for machine processing and reasoning), knowledge sharing (how to enable agents to acquire consistent knowledge from unreliable sensors and agents), and user privacy protection (how to give users control of their private information that the system acquires). To address these issues, I developed a new agent architecture called the Context Broker Architecture (CoBrA). It uses the Web Ontology Language OWL to define ontologies for context representation and modeling, defines rule-based logical inference for context reasoning and knowledge maintenance, and provides a policy language for users to control the sharing of their private information. Central to CoBrA is a server agent called context broker. Its role is to maintain a consistent model of context that can be shared by all computing entities in the space and to enforce the user-defined policies for privacy protection. The major research contributions of this work include a broker-centric architecture for supporting context-aware systems, a standard pervasive computing ontology, a reasoning approach that integrates assumption-based reasoning and argumentation for resolving inconsistent contextual knowledge, and a privacy protection mechanism that exploits information granularity adjustment. To demonstrate the feasibility of CoBrA, I prototyped a context broker in the FIPA platform using the JADE API library. I showed its use in supporting EasyMeeting, a smart meeting room system that provides context-aware services for assisting speakers and audiences. Other contributions include the CoBrA Demo Toolkit (an open source software package for demonstrating various aspects of CoBrA) and the CoBrA Text Messaging Commands (a text messaging interface for mobile users to interact with a context broker via SMS messages). The lessons learned from this research are as the follows. (i) CoBrA's broker-centric design can help to reduce the time and effort to rapidly prototype context-aware applications. (ii) Ontologies expressed using the OWL language can provide a uniformed solution for context representation and reasoning, knowledge sharing, and meta-language definitions. (iii) Rule-based logical inference can help to develop flexible context-aware systems by separating high-level context reasoning from low-level system behaviors.
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paper_title: An Architecture to Support Context-Aware Applications

paper_content:

Context is an important, yet poorly utilized source of information in interactive computing. It is difficult to use because, unlike other forms of user input, there is no common, reusable way to handle context. Most contextaware applications have been built in an ad hoc manner. We discuss the requirements for dealing with context and present an architectural solution we have designed and implemented to help application designers build contextaware applications more easily. We illustrate the use of the architecture through a context-aware application that assists conference attendees.
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paper_title: A context-aware middleware for applications in mobile Ad Hoc environments

paper_content:

Novel ubiquitous computing applications such as intelligent vehicles, smart buildings, and traffic management require special properties that traditional computing applications do not support, such as context-awareness, massive decentralisation, autonomous behaviour, adaptivity, proactivity, and innate collaboration. This paper presents a new computational model and middleware that reflect support for the required the properties. The sentient object model is proposed by the CORTEX1 project to support the construction of ubiquitous applications. A flexible, run-time reconfigurable component-based middleware has been built to provide run-time support to engineer the sentient object programming paradigm. An application infrastructure using sentient objects to enable cooperation between autonomous and proactive vehicles has been implemented to demonstrate the appropriateness of the computational model and the validity of the middleware for pervasive mobile ad hoc computing.
---
paper_title: A Middleware Infrastructure for Active Spaces

paper_content:

The paper discusses the Gaia metaoperating system which extends the reach of traditional operating systems to manage ubiquitous computing habitats and living spaces as integrated programmable environments. Gaia exports services to query, access, and use existing resources and context, and provides a framework to develop user-centric, resource-aware, multidevice, context-sensitive, and mobile applications.
---
paper_title: 'Caches in the air': disseminating tourist information in the GUIDE system

paper_content:

The paper describes work carried out as part of the GUIDE project at Lancaster University. The overall aim of the project is to develop a context-sensitive tourist guide for visitors to the city of Lancaster. Visitors are equipped with portable GUIDE units which in turn provide interactive services and dynamically tailored Web based information, reflecting the visitor's preferences and environmental context. In contrast to existing tourist systems, all information in GUIDE is obtained dynamically using a city-wide wireless network infrastructure. We focus on the design of the GUIDE information model. The model presented is novel by virtue of the fact that it enables both geographic and contextual information to be captured. The paper also describes our development of an efficient broadcast mechanism which enables visitors' requests for information to be serviced quickly despite the wireless communications infrastructure employed.
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paper_title: Disseminating active map information to mobile hosts

paper_content:

The article describes an active map service (AMS) that supports context-aware computing by providing clients with information about located-objects and how those objects change over time. The authors focus on the communication issues of disseminating information from an active map server to its clients, and in particular, address how to deal with various overload situations that can occur. Simple unicast callbacks to interested clients work well enough if only a few located-objects are moving at any given time and only a few clients wish to know about any given move. However, if many people are moving about in the same region and many clients are interested in their motion, then the AMS may experience overload due to the quadratic nature of the communications involved. This overload affects both the server as well as any slow communications links being used. Mobile distributed computing enables users to interact with many different mobile and stationary computers over the course of the day. Navigating a mobile environment can be aided by active maps that describe the location and characteristics of objects within some region as they change over time. >
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paper_title: Context Awareness in Mobile Computing Environments

paper_content:

In this article, we report software architectures for context awareness in mobile computing environments, sensor centric systems and discuss context modeling issues. Defining an architecture for supporting context-aware applications for mobile devices explicitly implies a scalable description of how to represent contextual information and which are the abstraction models capable of handling such information. Using sensors to retrieve contextual information (e.g., user location) leads to a sensor network scheme that provides services to the applications level. Operations for capturing, collating, storing, and disseminating contextual information at the lowest level and aggregating it into increasingly more abstract models qualify the context-aware systems. In this article, we introduce context aware systems in mobile computing environments, review the basic mechanisms underlying the operation of such systems, and discuss notable work and important architectures in the area.
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paper_title: Efficient reasoning

paper_content:

Many tasks require “reasoning”—i.e., deriving conclusions from a corpus of explicitly stored information—to solve their range of problems. An ideal reasoning system would produce all-and-only the correct answers to every possible query, produce answers that are as specific as possible, be expressive enough to permit any possible fact to be stored and any possible query to be asked, and be (time) efficient . Unfortunately, this is provably impossible: as correct and precise systems become more expressive, they can become increasingly inefficient, or even undecidable. This survey first formalizes these hardness results, in the context of both logic- and probability-based reasoning, then overviews the techniques now used to address, or at least side-step, this dilemma.
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paper_title: Human Activity Recognition and Pattern Discovery

paper_content:

In principle, activity recognition can be exploited to great societal benefits, especially in real-life, human centric applications such as elder care and healthcare. This article focused on recognizing simple human activities. Recognizing complex activities remains a challenging and active area of research and the nature of human activities poses different challenges. Human activity understanding encompasses activity recognition and activity pattern discovery. The first focuses on accurate detection of human activities based on a predefined activity model. An activity pattern discovery researcher builds a pervasive system first and then analyzes the sensor data to discover activity patterns.
---
paper_title: Bayesian approach to sensor-based context awareness

paper_content:

AbstractThe usability of a mobile device and services can be enhanced by context awareness. The aim of this experiment was to expand the set of generally recognizable constituents of context concerning personal mobile device usage. Naive Bayesian networks were applied to classify the contexts of a mobile device user in her normal daily activities. The distinguishing feature of this experiment in comparison to earlier context recognition research is the use of a naive Bayes framework, and an extensive set of audio features derived partly from the algorithms of the upcoming MPEG-7 standard. The classification was based mainly on audio features measured in a home scenario. The classification results indicate that with a resolution of one second in segments of 5–30 seconds, situations can be extracted fairly well, but most of the contexts are likely to be valid only in a restricted scenario. Naive Bayes framework is feasible for context recognition. In real world conditions, the recognition accuracy using leave-one-out cross validation was 87% of true positives and 95% of true negatives, averaged over nine eight-minute scenarios containing 17 segments of different lengths and nine different contexts. Respectively, the reference accuracies measured by testing with training data were 88% and 95%, suggesting that the model was capable of covering the variability introduced in the data on purpose. Reference recognition accuracy in controlled conditions was 96% and 100%, respectively. However, from the applicability viewpoint, generalization remains a problem, as from a wider perspective almost any feature may refer to many possible real world situations.
---
paper_title: Human Activity Recognition and Pattern Discovery

paper_content:

In principle, activity recognition can be exploited to great societal benefits, especially in real-life, human centric applications such as elder care and healthcare. This article focused on recognizing simple human activities. Recognizing complex activities remains a challenging and active area of research and the nature of human activities poses different challenges. Human activity understanding encompasses activity recognition and activity pattern discovery. The first focuses on accurate detection of human activities based on a predefined activity model. An activity pattern discovery researcher builds a pervasive system first and then analyzes the sensor data to discover activity patterns.
---
paper_title: Ontology based context modeling and reasoning using OWL

paper_content:

Here we propose an OWL encoded context ontology (CONON) for modeling context in pervasive computing environments, and for supporting logic-based context reasoning. CONON provides an upper context ontology that captures general concepts about basic context, and also provides extensibility for adding domain-specific ontology in a hierarchical manner. Based on this context ontology, we have studied the use of logic reasoning to check the consistency of context information, and to reason over low-level, explicit context to derive high-level, implicit context. By giving a performance study for our prototype, we quantitatively evaluate the feasibility of logic based context reasoning for nontime-critical applications in pervasive computing environments, where we always have to deal carefully with the limitation of computational resources.
---
paper_title: An Ontology for Context-Aware Pervasive Computing Environments

paper_content:

This document describes COBRA-ONT, an ontology for supporting pervasive context-aware systems. COBRA-ONT, expressed in the Web Ontology Language OWL, is a collection of ontologies for describing places, agents and events and their associated properties in an intelligent meeting-room domain. This ontology is developed as a part of the Context Broker Architecture (CoBrA), a broker-centric agent architecture that provides knowledge sharing, context reasoning and privacy protection supports for pervasive context-aware systems. We also describe an inference engine for reasoning with information expressed using the COBRA-ONT ontology and the ongoing research in using the DAML-Time ontology for context reasoning.
---
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.
---
paper_title: Semantic approach to context management and reasoning in ubiquitous context-aware systems

paper_content:

Ubiquitous computing involves applications that adapt their behavior to every changing physical, social, and computing environment. This can be realized through proper capturing, representation, management and reasoning of constantly changing context. In this work, we propose a hybrid approach to collaborative context management. It uses semantic ontology and relational schema. System scalability is addressed by heuristic based selective loading of relevant context data into the reasoner. We have also developed a collaborative platform that performs context-aware reasoning and decisions based on the context management model. A result from the preliminaiy test shows that our data model is scalable and the platform is domain independent.
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paper_title: Machine Recognition of Human Activities: A Survey

paper_content:

The past decade has witnessed a rapid proliferation of video cameras in all walks of life and has resulted in a tremendous explosion of video content. Several applications such as content-based video annotation and retrieval, highlight extraction and video summarization require recognition of the activities occurring in the video. The analysis of human activities in videos is an area with increasingly important consequences from security and surveillance to entertainment and personal archiving. Several challenges at various levels of processing-robustness against errors in low-level processing, view and rate-invariant representations at midlevel processing and semantic representation of human activities at higher level processing-make this problem hard to solve. In this review paper, we present a comprehensive survey of efforts in the past couple of decades to address the problems of representation, recognition, and learning of human activities from video and related applications. We discuss the problem at two major levels of complexity: 1) "actions" and 2) "activities." "Actions" are characterized by simple motion patterns typically executed by a single human. "Activities" are more complex and involve coordinated actions among a small number of humans. We will discuss several approaches and classify them according to their ability to handle varying degrees of complexity as interpreted above. We begin with a discussion of approaches to model the simplest of action classes known as atomic or primitive actions that do not require sophisticated dynamical modeling. Then, methods to model actions with more complex dynamics are discussed. The discussion then leads naturally to methods for higher level representation of complex activities.
---
paper_title: Human Activity Recognition and Pattern Discovery

paper_content:

In principle, activity recognition can be exploited to great societal benefits, especially in real-life, human centric applications such as elder care and healthcare. This article focused on recognizing simple human activities. Recognizing complex activities remains a challenging and active area of research and the nature of human activities poses different challenges. Human activity understanding encompasses activity recognition and activity pattern discovery. The first focuses on accurate detection of human activities based on a predefined activity model. An activity pattern discovery researcher builds a pervasive system first and then analyzes the sensor data to discover activity patterns.
---
paper_title: Naive (Bayes) at Forty: The Independence Assumption in Information Retrieval

paper_content:

The naive Bayes classifier, currently experiencing a renaissance in machine learning, has long been a core technique in information retrieval. We review some of the variations of naive Bayes models used for text retrieval and classification, focusing on the distributional assumptions made about word occurrences in documents.
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paper_title: An introduction to hidden Markov models

paper_content:

The basic theory of Markov chains has been known to mathematicians and engineers for close to 80 years, but it is only in the past decade that it has been applied explicitly to problems in speech processing. One of the major reasons why speech models, based on Markov chains, have not been developed until recently was the lack of a method for optimizing the parameters of the Markov model to match observed signal patterns. Such a method was proposed in the late 1960's and was immediately applied to speech processing in several research institutions. Continued refinements in the theory and implementation of Markov modelling techniques have greatly enhanced the method, leading to a wide range of applications of these models. It is the purpose of this tutorial paper to give an introduction to the theory of Markov models, and to illustrate how they have been applied to problems in speech recognition.
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paper_title: Conditional Random Fields: Probabilistic Models for Segmenting and Labeling Sequence Data

paper_content:

We present conditional random fields , a framework for building probabilistic models to segment and label sequence data. Conditional random fields offer several advantages over hidden Markov models and stochastic grammars for such tasks, including the ability to relax strong independence assumptions made in those models. Conditional random fields also avoid a fundamental limitation of maximum entropy Markov models (MEMMs) and other discriminative Markov models based on directed graphical models, which can be biased towards states with few successor states. We present iterative parameter estimation algorithms for conditional random fields and compare the performance of the resulting models to HMMs and MEMMs on synthetic and natural-language data.
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paper_title: Layered representations for human activity recognition

paper_content:

We present the use of layered probabilistic representations using Hidden Markov Models for performing sensing, learning, and inference at multiple levels of temporal granularity. We describe the use of the representation in a system that diagnoses states of a user's activity based on real-time streams of evidence from video, acoustic, and computer interactions. We review the representation, present an implementation, and report on experiments with the layered representation in an office-awareness application.
---
paper_title: Maxent, Mathematics, and Information Theory

paper_content:

This is a mathematically oriented survey about the method of maximum entropy or minimum I-divergence, with a critical treatment of its various justifications and relation to Bayesian statistics. Information theoretic ideas are given substantial attention, including “information geometry”. The axiomatic approach is considered as the best justification of maxent, as well as of alternate methods of minimizing some Bregman distance or f-divergence other than I-divergence. The possible interpretation of such alternate methods within the original maxent paradigm is also considered.
---
paper_title: Bayesian approach to sensor-based context awareness

paper_content:

AbstractThe usability of a mobile device and services can be enhanced by context awareness. The aim of this experiment was to expand the set of generally recognizable constituents of context concerning personal mobile device usage. Naive Bayesian networks were applied to classify the contexts of a mobile device user in her normal daily activities. The distinguishing feature of this experiment in comparison to earlier context recognition research is the use of a naive Bayes framework, and an extensive set of audio features derived partly from the algorithms of the upcoming MPEG-7 standard. The classification was based mainly on audio features measured in a home scenario. The classification results indicate that with a resolution of one second in segments of 5–30 seconds, situations can be extracted fairly well, but most of the contexts are likely to be valid only in a restricted scenario. Naive Bayes framework is feasible for context recognition. In real world conditions, the recognition accuracy using leave-one-out cross validation was 87% of true positives and 95% of true negatives, averaged over nine eight-minute scenarios containing 17 segments of different lengths and nine different contexts. Respectively, the reference accuracies measured by testing with training data were 88% and 95%, suggesting that the model was capable of covering the variability introduced in the data on purpose. Reference recognition accuracy in controlled conditions was 96% and 100%, respectively. However, from the applicability viewpoint, generalization remains a problem, as from a wider perspective almost any feature may refer to many possible real world situations.
---
paper_title: Some contributions to the metatheory of the situation calculus

paper_content:

We focus on a rich axiomatization for actions in the situation calculus that includes, among other features, a solution to the frame problem for deterministic actions. Our work is foundational in nature, directed at simplifying the entailment problem for these axioms. Specifically, we make four contributions to the metatheory of situation calculus axiomatizations of dynamical systems: (1) We prove that the above-mentioned axiomatization for actions has a relative satisfiability property; the full axiomatization is satisfiable iff the axioms for the initial state are. (2)We define the concept of regression relative to these axioms, and prove a soundness and completeness theorem for a regression-based approach to the entailment problem for a wide class of queries. (3) Our formalization of the situation calculus requires certain foundational axioms specifying the domain of situations. These include an induction axiom, whose presence complicates human and automated reasoning in the situation calculus. We characterize various classes of sentences whose proofs do not require induction, and in some cases, some of the other foundational axioms. (4)We prove that the logic programming language GOLOG never requires any of the foundational axioms for the evaluation of programs.
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paper_title: A Framework for Imprecise Context Reasoning

paper_content:

The knowledge about the user context refers to a sequence of activities performed in a pervasive computing environment. Such sequence and the corresponding context transitions typically constitute the up-to-now user situation, thus, clusters of similar situations can be formed. A framework that represents and infers the current user context and reasons about user situations through approximate reasoning and clustering techniques is proposed .
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paper_title: Activity recognition via user-trace segmentation

paper_content:

A major issue of activity recognition in sensor networks is automatically recognizing a user's high-level goals accurately from low-level sensor data. Traditionally, solutions to this problem involve the use of a location-based sensor model that predicts the physical locations of a user from the sensor data. This sensor model is often trained offline, incurring a large amount of calibration effort. In this article, we address the problem using a goal-based segmentation approach, in which we automatically segment the low-level user traces that are obtained cheaply by collecting the signal sequences as a user moves in wireless environments. From the traces we discover primitive signal segments that can be used for building a probabilistic activity model to recognize goals directly. A major advantage of our algorithm is that it can reduce a significant amount of human effort in calibrating the sensor data while still achieving comparable recognition accuracy. We present our theoretical framework for activity recognition, and demonstrate the effectiveness of our new approach using the data collected in an indoor wireless environment.
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paper_title: Model-based ambient analysis of human task execution

paper_content:

One of the challenges for ambient intelligent agents to support a human in demanding tasks, is to find out and be aware of what the human is exactly doing, and how much progress is made. Of course, in principle it would be possible to interact with the human to discover what this human is doing, but this communication can potentially slow down or even endanger task performance. In this paper an ambient agent model is presented that is able to obtain such an awareness of the human's progress in task execution by performing model-based analysis using available workflow models and available observation information. The design of the model is based on a component-based generic ambient agent model. Simulation experiments for a case study are discussed, and evaluated by automated formal verification.
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paper_title: Model-Based Reasoning Methods within an Ambient Intelligent Agent Model

paper_content:

Ambient agents react on humans on the basis of their information obtained by sensoring and their knowledge about human functioning. Appropriate types of reactions depend on in how far an ambient agent understands the human. On the one hand, such an understanding requires that the agent has knowledge to a certain depth about the human’s physiological and mental processes in the form of an explicitly represented model of the causal and dynamic relations describing these processes. On the other hand, given such a model representation, the agent needs reasoning methods to derive conclusions from the model and the information available by sensoring. This paper presents a number of such model-based reasoning methods. They have been formally specified in an executable temporal format, which allows for simulation of reasoning traces and automated verification in a dedicated software environment. A number of such simulation experiments and their formal analysis are described.
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paper_title: A Situation Calculus-based Approach To Model Ubiquitous Information Services

paper_content:

This paper presents an augmented situation calculus-based approach to model autonomous computing paradigm in ubiquitous information services. To make it practical for commercial development and easier to support autonomous paradigm imposed by ubiquitous information services, we made improvements based on Reiter's standard situation calculus. First we explore the inherent relationship between fluents and evolution: since not all fluents contribute to systems' evolution and some fluents can be derived from some others, we define those fluents that are sufficient and necessary to determine evolutional potential as decisive fluents, and then we prove that their successor states wrt to deterministic complex actions satisfy Markov property. Then, within the calculus framework we build, we introduce validity theory to model the autonomous services with application-specific validity requirements, including: validity fluents to axiomatize validity requirements, heuristic multiple alternative service choices ranging from complete acceptance, partial acceptance, to complete rejection, and validity-ensured policy to comprise such alternative service choices into organic, autonomously-computable services. Our approach is demonstrated by a ubiquitous calendaring service, ACS, throughout the paper.
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paper_title: Evaluating Pervasive and Ubiquitous Systems

paper_content:

Recognized evaluation strategies are essential to systematically advance a research field's state of the art. Pervasive and ubiquitous computing need such strategies to mature as a discipline and to enable researchers to objectively assess and compare new techniques' contributions. Researchers have shown that evaluating ubiquitous systems can be difficult, so approaches tend to be subjective, piecemeal, or both. To ensure that the validity and usability of proposed systems won't be compromised, researchers must reach consensus on a set of standard evaluation methods for ubiquitous systems. Otherwise, methods for scientifically testing and presenting state-of-the-art advances will remain unclear. In this article, the organizers from four different workshop series, each focused on this topic, summarize and discuss the main outcomes of these events.
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paper_title: Context-aware office assistant

paper_content:

This paper describes the design and implementation of the Office Assistant — an agent that interacts with visitors at the office door and manages the office owner's schedule. We claim that rich context information about users is key to making a flexible and believable interaction. We also argue that natural face-to-face conversation is an appropriate metaphor for human-computer interaction.
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paper_title: CybreMinder: A Context-Aware System for Supporting Reminders

paper_content:

Current tools do not provide adequate support to users for handling reminders. The main reason for this is the lack of use of rich context that specifies when a reminder should be presented to its recipient. We describe Cybre-Minder, a prototype context-aware tool that supports users in sending and receiving reminders that can be associated to richly described situations involving time, place and more sophisticated pieces of context. These situations better define when reminders should be delivered, enhancing our ability to deal with them more effectively. We describe how the tool is used and how it was developed using our previously developed Context Toolkit infrastructure for context-aware computing.
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paper_title: The active badge location system

paper_content:

A novel system for the location of people in an office environment is described. Members of staff wear badges that transmit signals providing information about their location to a centralized location service, through a network of sensors. The paper also examines alternative location techniques, system design issues and applications, particularly relating to telephone call routing. Location systems raise concerns about the privacy of an individual and these issues are also addressed.
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paper_title: A Middleware Infrastructure for Active Spaces

paper_content:

The paper discusses the Gaia metaoperating system which extends the reach of traditional operating systems to manage ubiquitous computing habitats and living spaces as integrated programmable environments. Gaia exports services to query, access, and use existing resources and context, and provides a framework to develop user-centric, resource-aware, multidevice, context-sensitive, and mobile applications.
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paper_title: 'Caches in the air': disseminating tourist information in the GUIDE system

paper_content:

The paper describes work carried out as part of the GUIDE project at Lancaster University. The overall aim of the project is to develop a context-sensitive tourist guide for visitors to the city of Lancaster. Visitors are equipped with portable GUIDE units which in turn provide interactive services and dynamically tailored Web based information, reflecting the visitor's preferences and environmental context. In contrast to existing tourist systems, all information in GUIDE is obtained dynamically using a city-wide wireless network infrastructure. We focus on the design of the GUIDE information model. The model presented is novel by virtue of the fact that it enables both geographic and contextual information to be captured. The paper also describes our development of an efficient broadcast mechanism which enables visitors' requests for information to be serviced quickly despite the wireless communications infrastructure employed.
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paper_title: inContext: A Pervasive and Collaborative Working Environment for Emerging Team Forms

paper_content:

Participants in current team collaborations belong to different organizations, work on multiple objectives at the same time, and frequently change locations. They use different devices and infrastructures in collaboration processes that can last from a few hours to several years. All these factors pose new challenges to the development of collaborative working environments (CWEs). Existing CWEs are unable to support emerging teams because diverse collaboration services are not well integrated or adapting to the team context. We present the inContext approach to providing a novel pervasive CWE infrastructure for emerging team forms. inContext aggregates disparate collaboration services using Web services and Semantic Web technologies and provides a platform that captures diverse dynamic aspects of team collaborations. By utilizing runtime and historical context and interaction information, adaptation techniques can be deployed to cope with the changes of emerging teams.
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paper_title: Disseminating active map information to mobile hosts

paper_content:

The article describes an active map service (AMS) that supports context-aware computing by providing clients with information about located-objects and how those objects change over time. The authors focus on the communication issues of disseminating information from an active map server to its clients, and in particular, address how to deal with various overload situations that can occur. Simple unicast callbacks to interested clients work well enough if only a few located-objects are moving at any given time and only a few clients wish to know about any given move. However, if many people are moving about in the same region and many clients are interested in their motion, then the AMS may experience overload due to the quadratic nature of the communications involved. This overload affects both the server as well as any slow communications links being used. Mobile distributed computing enables users to interact with many different mobile and stationary computers over the course of the day. Navigating a mobile environment can be aided by active maps that describe the location and characteristics of objects within some region as they change over time. >
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paper_title: Tools for Studying Behavior and Technology in Natural Settings

paper_content:

Three tools for acquiring data about people, their behavior, and their use of technology in natural settings are described: (1) a context-aware experience sampling tool, (2) a ubiquitous sensing system that detects environmental changes, and (3) an image-based experience sampling system. We discuss how these tools provide researchers with a flexible toolkit for collecting data on activity in homes and workplaces, particularly when used in combination. We outline several ongoing studies to illustrate the versatility of these tools. Two of the tools are currently available to other researchers to use.
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paper_title: MyExperience: a system for in situ tracing and capturing of user feedback on mobile phones

paper_content:

This paper presents MyExperience, a system for capturing both objective and subjective in situ data on mobile computing activities. MyExperience combines the following two techniques: 1) passive logging of device usage, user context, and environmental sensor readings, and 2) active context-triggered user experience sampling to collect in situ, subjective user feedback. MyExperience currently runs on mobile phones and supports logging of more than 140 event types, including: 1) device usage such as communication, application usage, and media capture, 2) user context such as calendar appointments, and 3) environmental sensing such as Bluetooth and GPS. In addition, user experience sampling can be targeted to moments of interest by triggering off sensor readings. We present several case studies of field deployments on people's personal phones to demonstrate how MyExperience can be used effectively to understand how people use and experience mobile technology.
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paper_title: Supporting ethnographic studies of ubiquitous computing in the wild

paper_content:

Ethnography has become a staple feature of IT research over the last twenty years, shaping our understanding of the social character of computing systems and informing their design in a wide variety of settings. The emergence of ubiquitous computing raises new challenges for ethnography however, distributing interaction across a burgeoning array of small, mobile devices and online environments which exploit invisible sensing systems. Understanding interaction requires ethnographers to reconcile interactions that are, for example, distributed across devices on the street with online interactions in order to assemble coherent understandings of the social character and purchase of ubiquitous computing systems. We draw upon four recent studies to show how ethnographers are replaying system recordings of interaction alongside existing resources such as video recordings to do this and identify key challenges that need to be met to support ethnographic study of ubiquitous computing in the wild.
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paper_title: Acquiring in situ training data for context-aware ubiquitous computing applications

paper_content:

Ubiquitous, context-aware computer systems may ultimately enable computer applications that naturally and usefully respond to a user's everyday activity. Although new algorithms that can automatically detect context from wearable and environmental sensor systems show promise, many of the most flexible and robust systems use probabilistic detection algorithms that require extensive libraries of training data with labeled examples. In this paper, we describe the need for such training data and some challenges we have identified when trying to collect it while testing three context-detection systems for ubiquitous computing and mobile applications.
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paper_title: A context-aware experience sampling tool

paper_content:

A new software tool for user-interface development and assessment of ubiquitous computing applications is available for CHI researchers. The software permits researchers to use common PDA mobile computing devices for experience sampling studies. The basic tool offers options not currently available in any other open-source sampling package. However, the tool also has new functionality: context-aware experience sampling. This feature permits researchers to acquire feedback from users in particular situations that are detected by sensors connected to a mobile computing device.
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paper_title: Momento: support for situated ubicomp experimentation

paper_content:

We present the iterative design of Momento, a tool that providesintegrated support for situated evaluation of ubiquitouscomputing applications. We derived requirements for Momento from a user-centered design process that includedinterviews, observations and field studies of early versionsof the tool. Motivated by our findings, Momento supportsremote testing of ubicomp applications, helps with participantadoption and retention by minimizing the need for newhardware, and supports mid-to-long term studies to addressinfrequently occurring data. Also, Momento can gather logdata, experience sampling, diary, and other qualitative data.
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paper_title: Activity-based prototyping of ubicomp applications for long-lived, everyday human activities

paper_content:

We designed an activity-based prototyping process realized in the ActivityDesigner system that combines the theoretical framework of Activity-Centered Design with traditional iterative design. This process allows designers to leverage human activities as first class objects for design and is supported in ActivityDesigner by three novel features. First, this tool allows designers to model activities based on concrete scenarios collected from everyday lives. The models form a context for design and computational constructs for creating functional prototypes. Second, it allows designers to prototype interaction behaviors based on activity streams spanning time. Third, it allows designers to easily test these prototypes with real users continuously, in situ. We have garnered positive feedback from a series of laboratory user studies and several case studies in which ActivityDesigner was used in realistic design situations. ActivityDesigner was able to effectively streamline a ubicomp design process, and it allowed creating realistic ubicomp application prototypes at a low cost and testing them in everyday lives over an extended period.
---
paper_title: Using the experience sampling method to evaluate ubicomp applications

paper_content:

Ubiquitous computing's overarching goal is for technology to disappear into the background yet remain useful to users. A technique from the field of psychology - the experience sampling method - could help researchers improve ubiquitous computing's evaluation process.
---
paper_title: MyExperience: a system for in situ tracing and capturing of user feedback on mobile phones

paper_content:

This paper presents MyExperience, a system for capturing both objective and subjective in situ data on mobile computing activities. MyExperience combines the following two techniques: 1) passive logging of device usage, user context, and environmental sensor readings, and 2) active context-triggered user experience sampling to collect in situ, subjective user feedback. MyExperience currently runs on mobile phones and supports logging of more than 140 event types, including: 1) device usage such as communication, application usage, and media capture, 2) user context such as calendar appointments, and 3) environmental sensing such as Bluetooth and GPS. In addition, user experience sampling can be targeted to moments of interest by triggering off sensor readings. We present several case studies of field deployments on people's personal phones to demonstrate how MyExperience can be used effectively to understand how people use and experience mobile technology.
---
paper_title: Using a Live-In Laboratory for Ubiquitous Computing Research

paper_content:

Ubiquitous computing researchers are increasingly turning to sensor-enabled living laboratories for the study of people and technologies in settings more natural than a typical laboratory. We describe the design and operation of the PlaceLab, a new live-in laboratory for the study of ubiquitous technologies in home settings. Volunteer research participants individually live in the PlaceLab for days or weeks at a time, treating it as a temporary home. Meanwhile, sensing devices integrated into the fabric of the architecture record a detailed description of their activities. The facility generates sensor and observational datasets that can be used for research in ubiquitous computing and other fields where domestic contexts impact behavior. We describe some of our experiences constructing and operating the living laboratory, and we detail a recently generated sample dataset, available online to researchers.
---
paper_title: UBIWISE, A Simulator for Ubiquitous Computing Systems Design

paper_content:

We describe UbiWise, a simulator for ubiquitous computing. The simulator concentrates on computation and communications devices situated within their physical environments. It presents two views, each in a separate window on the desktop of the users' PC. One of the views provides a three dimensional world, built on the Quake III Arena graphics engine and serves to simulate a first-person view of the physical environment of a user. The other view, built using Java, shows a close-up view of devices and objects the user may manipulate. These views act as one unified whole by maintaining a clientserver model with a central server. Multiple users can attach to the same server to create interactive ubiquitous computing scenarios. We describe how UbiWise looks to researchers and examples of its use as tool for ubiquitous computing research.
---
paper_title: Performance simulation of a context provisioning middleware based on empirical measurements

paper_content:

The evaluation of context middleware systems is a challenging endeavour. On the one hand, testbed investigations suffer from an unrealistic environment in terms of number of users, high implementation effort for changes and questionable portability of results. On the other hand simulation of middleware systems is complex due to the high abstraction of implementation. This article contributes to the understanding of a broker based context provisioning system based on black-box measurements of a testbed which are further utilised to increase the accuracy of a simulation model. Both simulations and measurements help in understanding the complex behaviour of a context provisioning middleware and enable the evaluation of complex distributed systems. The presented investigations identify significant parameters and corresponding models for the response delay of the key components of a context provisioning middleware and discuss their integration into an overall simulation model.
---
paper_title: UbiREAL: Realistic Smartspace Simulator for Systematic Testing

paper_content:

In this paper, we propose a simulator for facilitating reliable and inexpensive development of ubiquitous applications where each application software controls a lot of information appliances based on the state of external environment, user's contexts and preferences. The proposed simulator realistically reproduces behavior of application software on virtual devices in a virtual 3D space. For this purpose, the simulator provides functions to facilitate deployment of virtual devices in a 3D space, simulates communication among the devices from MAC level to application level, and reproduces the change of physical quantities (e.g., temperature) caused by devices (e.g., air conditioners). Also, we keep software portability between virtual devices and real devices. As the most prominent function of the simulator, we provide a systematic and visual testing method for testing whether a given application software satisfies specified requirements.
---
paper_title: Evaluating a location-based application: a hybrid test and simulation environment

paper_content:

Complex and expensive testing and evaluation can inhibit cost-effective development of ubiquitous computing applications. A new environment for testing and evaluating system- and network-related issues in location-based applications strives to evaluate these applications prior to deployment. We discuss a health-monitoring application and its simulation environment.
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paper_title: A Generic Large Scale Simulator for Ubiquitous Computing

paper_content:

The complexity associated to gathering and processing contextual data makes testing mobile context-aware applications and services difficult. Furthermore, the lack of standard data sets and simulation tools makes the evaluation of machine learning algorithms in context-aware settings an even harder task. To ease the situation, we introduce a generic simulator that has been designed with the above mentioned purposes in mind. The simulator has also proven to be a good demonstration tool for mobile services and applications that are aimed at groups. The simulator is highly customizable and it can output context information of individual entities both through an interactive GUI and as data streams consisting of comma separated values. To support a wide range of tasks and scenarios, we have separated the three main information sources: behavior of agents, the scenario being simulated and the used context variable. The simulator has been implemented using Java, and the data streams have been made available through a web service interface.
---
paper_title: Opportunistic Cooperative Networking: To Relay or Not To Relay?

paper_content:

This paper considers opportunistic cooperative networking (OCN) in wireless ad hoc networks, with a focus on characterizing the desired tradeoff between the probing cost for establishing cooperative relaying and hence higher throughput via opportunistic cooperative networking. Specifically, opportunistic cooperative networking is treated as an optimal stopping problem with two-levels of incomplete information. Cases with or without dedicated relays are considered, and the existence of the optimal strategies for both cases are established. Then, it is shown that for the case with dedicated relays, the optimal strategy exhibits a threshold structure, in which it is optimal to probe the dedicated relay when the signal-to-noise ratio (SNR) of the source-relay link exceeds some threshold. For the case without dedicated relays, under more restrictive conditions, the optimal strategy is also threshold-based, in the sense that it is optimal to probe potential relays when the SNR of the source-destination link lies between two thresholds. Furthermore, these strategies can be implemented in a distributed manner.
---
paper_title: UBIWISE, A Simulator for Ubiquitous Computing Systems Design

paper_content:

We describe UbiWise, a simulator for ubiquitous computing. The simulator concentrates on computation and communications devices situated within their physical environments. It presents two views, each in a separate window on the desktop of the users' PC. One of the views provides a three dimensional world, built on the Quake III Arena graphics engine and serves to simulate a first-person view of the physical environment of a user. The other view, built using Java, shows a close-up view of devices and objects the user may manipulate. These views act as one unified whole by maintaining a clientserver model with a central server. Multiple users can attach to the same server to create interactive ubiquitous computing scenarios. We describe how UbiWise looks to researchers and examples of its use as tool for ubiquitous computing research.
---
paper_title: Performance simulation of a context provisioning middleware based on empirical measurements

paper_content:

The evaluation of context middleware systems is a challenging endeavour. On the one hand, testbed investigations suffer from an unrealistic environment in terms of number of users, high implementation effort for changes and questionable portability of results. On the other hand simulation of middleware systems is complex due to the high abstraction of implementation. This article contributes to the understanding of a broker based context provisioning system based on black-box measurements of a testbed which are further utilised to increase the accuracy of a simulation model. Both simulations and measurements help in understanding the complex behaviour of a context provisioning middleware and enable the evaluation of complex distributed systems. The presented investigations identify significant parameters and corresponding models for the response delay of the key components of a context provisioning middleware and discuss their integration into an overall simulation model.
---
paper_title: UbiREAL: Realistic Smartspace Simulator for Systematic Testing

paper_content:

In this paper, we propose a simulator for facilitating reliable and inexpensive development of ubiquitous applications where each application software controls a lot of information appliances based on the state of external environment, user's contexts and preferences. The proposed simulator realistically reproduces behavior of application software on virtual devices in a virtual 3D space. For this purpose, the simulator provides functions to facilitate deployment of virtual devices in a 3D space, simulates communication among the devices from MAC level to application level, and reproduces the change of physical quantities (e.g., temperature) caused by devices (e.g., air conditioners). Also, we keep software portability between virtual devices and real devices. As the most prominent function of the simulator, we provide a systematic and visual testing method for testing whether a given application software satisfies specified requirements.
---

Title: Survey of Context Provisioning Middleware
Section 1: INTRODUCTION
Description 1: Introduce the concept of ubiquitous computing (UbiComp), its evolution, and the role of context-awareness in simplifying Human Computer Interaction (HCI).

Section 2: Context and Context-awareness
Description 2: Define context, context-awareness, and discuss their significance in facilitating proactive support for users.

Section 3: Context-aware Systems
Description 3: Describe the functionalities required in context-aware systems, their layered middleware design, and the challenges they face.

Section 4: Major Contributions
Description 4: Summarize the significant contributions of the paper in various aspects of context-aware systems like context modelling, context management, context reasoning, and evaluation.

Section 5: Structure
Description 5: Explain the structure of the paper and how different sections are organized.

Section 6: Ubiquitous Computing
Description 6: Detail the evolution of Ubiquitous Computing from mobile communication, highlighting its reliance on context-awareness.

Section 7: Context
Description 7: Explore different definitions and classifications of context, and the significance of context elements.

Section 8: Context-Awareness
Description 8: Discuss the lifecycle of context data and types of context-aware systems, showing how these systems adapt to specific contexts.

Section 9: CONTEXT MODELLING & REPRESENTATION
Description 9: Describe the process of context modelling, objectives for a uniform and machine-processable context representation scheme, and different modelling approaches.

Section 10: Classification of Context Models
Description 10: Discuss various classifications of context models like key-value models, markup scheme models, and logic-based models.

Section 11: Context Meta Data
Description 11: Cover the importance of context metadata, including quality of information, degree of uncertainty, and temporal aspects.

Section 12: CONTEXT MANAGEMENT & PROVISIONING
Description 12: Explain the key functions of context management like sensor data acquisition, context storage, and diffusion, along with existing classification and design approaches.

Section 13: Functionalities
Description 13: Detail the individual functionalities and tasks involved in context management and provisioning.

Section 14: Existing Classifications
Description 14: Outline existing classifications of context middleware approaches and provide a basis for further subdivisions.

Section 15: Design-based Classification of Context Provisioning Middleware
Description 15: Discuss various design approaches for context provisioning middleware such as layered, object-oriented, and event-based designs.

Section 16: Architectural Classification of Context Middleware
Description 16: Classify middleware systems based on their architectural approaches like context server based, peer-to-peer, and direct sensor coupled architectures.

Section 17: Implementation
Description 17: Describe different technologies used for implementing context-aware middleware, such as RMI, CORBA, OSGI, and web services.

Section 18: Overview of Related Frameworks and Middleware
Description 18: Provide an overview of various context-aware systems and middleware frameworks, discussing their historical evolution, major achievements, and limitations.

Section 19: CONTEXT PROCESSING & REASONING
Description 19: Discuss reasoning mechanisms for inferring high-level context from lower-level context, covering rule-based reasoning, description logic, and probabilistic models.

Section 20: Context Processing and the Middleware
Description 20: Detail the stages of context processing and the role of middleware in facilitating data acquisition and reasoning.

Section 21: Rule-based Reasoning
Description 21: Explain the cycle of rule-based reasoning, including matching, conflict-resolution, and acting.

Section 22: Description Logic
Description 22: Discuss the utilisation of description logic for knowledge representation and reasoning in context-aware systems.

Section 23: Probabilistic Logic
Description 23: Describe the application of probabilistic models in context reasoning and their advantages in handling imprecise sensor data.

Section 24: Other Reasoning Mechanisms
Description 24: Cover alternative reasoning mechanisms like situation calculus, fuzzy logic, and workflow-inspired patterns.

Section 25: Context Middleware Evaluation
Description 25: Explore methodologies for evaluating context-aware middleware, highlighting the importance of multidisciplinary approaches.

Section 26: Challenges of Middleware Evaluation
Description 26: Discuss the primary challenges faced during the evaluation of context-aware middleware.

Section 27: Prototyping
Description 27: Explain the prototyping technique for evaluating middleware, including its benefits and limitations.

Section 28: Field Trials
Description 28: Describe the methodologies used in field trials for evaluating context-aware systems and their effectiveness.

Section 29: Emulation & Simulation
Description 29: Outline the use of emulation and simulation techniques for evaluating middleware and their relevance.

Section 30: Comparison of Methodologies
Description 30: Provide a comparative analysis of different evaluation methodologies for context middleware.

Section 31: Synopsis
Description 31: Summarize the survey, highlighting key observations and findings.

Section 32: Lessons Learnt
Description 32: Present the lessons learnt from the review and analysis of context provisioning middleware.

Section 33: Trends and Evolution
Description 33: Discuss the emerging trends and expected evolution in the domain of context-aware systems.

Section 34: Open Issues and Future Work
Description 34: Identify open research issues and propose future research objectives to advance context provisioning middleware.

Section 35: CONCLUSION
Description 35: Conclude the survey with a summary of the discussions, analyses, and recommendations for future research.