We are now about to hear about the set-by-fine and opening courses of materials. And we have Eileen Dorn, Alexander, Ida, the President. It works, all of them work. It's a lovely thing. People can make their own choices. The slides are there. The slide is at a short link. We have a z.umn.edu at the University of Minnesota. And so that's there, followed by the slash and alt-c23 slides. And there's another way to get to that. I just want to, before we do that, Ann Marie's keynote made me think about the fractal. And I'm definitely talking about something that's a fractal, a small thing that we're doing and going to export to a bigger. It's genuinely a road in my hand reminder that it's reflective practice that I'm talking about as we're moving on to next stages. I did open a VVox Q&A, especially if you're online and you want to add something there. So VVox.app and numbers 127067566. And I've already populated it with links, including the slides and a course site and a folder that I created as a clone of what I do in person. So, yeah, this 30 years of technology thing that I, in the middle, that was me as an undergraduate using those lovely, you know, hanging Chad cards. And I ran my first online discussion using a Gandalf box where people could come in one at a time to read and respond. And I taught in the first computer classroom at the University of Iowa because my partner developed the room and nobody was signing up to do it. And I did that in the house. I did that. But one of the things as I'm thinking about this with OER open educational resources I've created them using press reader for the most part, and I love to doing that. However, I've gotten many requests from people for having accessible documents, because the document conversion for PDF is difficult. We had a really hard time setting that up, because the docs came into us in ways that we had to make accessible to put into the press reader system. So I would do so many things differently now. And the format is definitely inclusive and accessible for people use screen readers. A colleague who uses and vises on screen reader says the rest of us are kind of screwed for accessibility if you need to print out, you need a Google Doc to highlight and work with it's really difficult to convert a press book into accessible documents. Somewhere along the way we also started at the university and initiative called the seven course skills it's kind of like sculpt here in the UK, where we teach people how to use alternative text contrast headings links, all of those things. And the pages all give people dos and don'ts. And that was really fun to populate and at the same time, we've populated it I noticed now it's become about using web pages designing web pages for screen readers. So it drops out a whole bunch of people with accessibility needs so it's barriers for people with a variety of accessibility needs. We started to address this last session they talked about something at Birmingham that they're doing with is a voluntary 30 minute module. We have a non voluntary, definitely mandated by module that's 30 minutes, three components. Minnesota faculty in the whole system we have five campuses across the state hate doing mandatory things. And we have 2000 people finish it. And they're asking for more opportunities to talk and more information. So even when it's compliance there's a lot of non compliance for mandatory things. And we focused on case studies and the follow up requests were for things like these resources are really great but I can't access them. I can't scan this and behind something else and the shareable documents with inside we're only PDFs which are a problem for some readers. So, I'm in doing all this I realized that one of the things I needed to go back to is thinking about who I do this work with because my own students were saying, I can actually use your documents and I have students with all kinds of disabilities and all kinds of factors about their technology people who are sharing computers people only have the phone people who can't ever take their computers out of the research lab, and are allowed to print in the research lab. So we're trying to figure out how to be connected and care about each other. In a particular class this was spring of 2020, and that was the spring that everything changed. So we went online and the students said can you give us documents that are in ways that we can print out we can download our own copies, we don't have to mess with PDFs and can you create something we can take away with us to use when we're out of the class and we can share with our colleagues. So I started making all the documents I had accessible that two eyes. So they were thinking about how to work with each other and they made the agreement to use all the accessibility guidelines from those seven core to do documents for my class to do documents for each other to do everything with each other so that it was accessible using the seven core skills. And also thinking about access and inclusion as conceptual things things you build into your course. So they had an eye and where they were and where they wanted to be. Now my students are future faculty. So they know that they're going to have to pay attention to accessibility and say that they do, and they're going to have to create documents, and that they're eventually going to have to create open access documents open educational resources. But I really wanted them to have the skills so they weren't dealing with things like I was like converting everybody's jumbled up documents into something that could be a press reader. They needed to be and so did they. And that was really lovely. And I went back at the same time to look at cofield and Edwards who talk their article is best practice what's next perfect practice they get at the idea of, we can't there isn't a best that things are mutable and adjustable who says it's a best practice. What's the evidence what's the criteria. So I started thinking about that it always pushed against best practice and I at least get people to go with effective practice if they're going to use one of those things and thought what can I do that's breaking and asking for whom best for whom what are the criteria and what conditions by looking at my teaching which I'd already done. And you have access to my course. It's in the notes field for these slides. So when you download them you'll be able to see a clone of the course. So I put in the assessment I'll say a bit about that I have the students think about how they interact with each other and share documents with each other. And I do this in professional development with faculty. So far I've impacted 250 students, 50 faculty, and in our online course design site where we brought all of this in during the tumult and the turnaround we had 800 faculty. So it's had a nice run of people trying this out and thinking about accessifying is, if you're going to do something that's open education and you're going to publish it how do you start out doing it in a way that's shareable so for example, the Google dot can become the word that can become the PDF.  So I work with my colleague Colled who were who helps people to create them. So thinking about all of that I really came back to this idea that we're in a system, and even when we're paying attention to accommodations, we're still in an ableist system in academics. Anyone who needs something beyond someone who's visually or physically impaired must have some sort of deficit, and I push against that as someone who's disabled I have a learning disability at physical disabilities and when this was really happening. I lost the site in one of my eyes because of a protein cloud so I had trouble reading. Toxic me needs to print out things needs to make comments. And if you've all tried making comments and keeping notes on a PDF. It's not the easiest thing in the world. Google Docs is much easier so as a paper copy that you can turn into a PDF if you really want to have it, but I need that in order to work effectively as a learner. So it really made me think about how I was adding to ableism by not paying attention to what my students were asking of me and helping them to become the teachers I wanted to be. So then Alastair McNaught is one of my favorite human beings. And I got a bunch of people to join in with me and doing this because one person can't do it. And there was this, you know, disability team, the specialists, the document conversion folks who are overwhelmed. So overwhelmed that when I said will you teach me the skills that you have they did, because I could do it for my own students. So we started realizing who all is involved in this there's a disability resource center. There's a center for teaching our academic technology center, our office for equity and diversity our graduate school our international student support, and we're all losing staff. So we had to figure out how to work together for something effective to teach people how to do this. So the students and the future faculty and the current faculty were actually producing the accessible documents and starting from the get go. So using that I started thinking about design, which is my favorite thing to think about in the world. So disability inclusion, and we had done a seminar five part seminar teaching with access and inclusion, using some of these ideas, and again trying to get faculty think about what's the small change that you can make. And it can be creating Google Docs, it can be doing document conversion, it can be something small and what's its big impact. One of the things we thought about in there is the inclusive part versus the accessible part, often inclusive is technical adaptability, and the other one is more attitudinal, the inclusive part how do we do this contextual change what is yes I can technically satisfy things by making PDFs that are available to a screen reader, and not all screen readers do that, but I also want to do the more approachable thing of how to make it inclusive that's more adaptable that people can adapt to their own needs. So this is my friend Collette slide, and Collette has been my constant partner in this, even to the point of you know when you do a hyperlink you're supposed to hyperlink the whole article title if you're doing an article. Collette and I have devised a system where we at the end say opens as a PDF or as a Google Doc and hyperlink, what it opens as. That's probably because my eyes stuff means the blue hurts. So I don't like look at my own pages with all the blue. But again that's adaptive, and we're trying to figure out how to do it and signal that it's okay. And I tell my students that beginning of the semester if they're used to something else, this is what you'll encounter. So this design instead of asking that you know aims what are your aims, I use aims for outcomes objectives all those things. We started asking questions, how will we work together. Instead of, you know, where what's our context how will we work together became the thing. And for working together with visually impaired students with hearing impaired students with students with multiple co occurring disabilities. I think about how to do that work together slightly differently so even with videos, I can see a video I can read the captions. I cannot understand when I'm looking at it on the screen, I need a transcript. So for podcasts and videos, I make a transcript available and put the link to the blog or the video or the podcast within that. And that question, I call this the four a's and I'm based in on bigs and Tang, and a little bit on the backward design stuff. So, you know what is it students what will learn and my classes undergrad as well as a grad they're going to learn how to create accessible materials and how to work together and how to do a step up so we down platform a little bit, but then they can up platform to an infographic to an ebook to other kinds of things because they've created the document. And then also how will they practice that learning. So, my students in the big class I do create a syllabus, and they practice their learning with accessibility by creating a word document syllabus. And then the next thing that I want to do is to look at that in terms of how did they use a seven core skills and the teaching with access and inclusion ideas, and how would they up platform it. So how would you use a infographic with it as an intro, and would you create a transcript for that info graphic if you were doing that how would you do it on canvas if you wanted a canvas set up so that becomes their assessment where they can. They're demonstrating how they would do it. So I use this to rethink my courses, and try to start formalizing it, which is what this year is about. I also did it because learning, and this is from James all again citations are in my notes field, who talks about us gathering data and often in academic spaces we gather data and then we go right to testing it right. And gathering is sensory, as well as cognitive. So, when that sensory information comes in, if you're feeling left out, and the morning keynote took on some of that you don't feel like you belong. If you can't access the course materials. So there's a distress and a shutting down this low level traumas. But if you can see yourself in it you pick it up and start to think about oh this is, this is what I do and I can create it in a different mode as well. So then, both reflecting and creating get open and people can test it out so my students have the goal of using accessible materials, they reflect on it in their assignments they do different things they create their final projects, and they tested out with their peers all the time. So we're trying to use all of those things and build the associations that inclusion is big and good. And there is another way of looking at this comes from a place called UDL online, who says, they point out that you need to separate the means from the ends and the end is an accessible course. But how people get there, could it be a syllabus could it be a canvas page that has all the files and all the right places. Could it be something else. So for my syllabus for my students they have to do the paper version, because that's the starting place, but then they get to go on and tell me how they're actually going to use it. And they learn some new accessibility skills along the ways along the way. Here's just a quick little look at the student part that we do. I think what's interesting is that I start with learning so that they're not thinking about people with disabled disabilities or disabled folks, or less than sorts of things but learning is like this learning needs guidance. And one of the things with this particular question from Steven shoe is the answer is actually the time you spend studying, and he amplifies that by saying you have an orienting task. So you're going to do this assignment to learn more about learning and how it works, but also to think about how to convey that to your learners in different ways. So we spend four weeks talking about learning, how does that impact what you design, and the kinds of learners you'll have first generation BIPOC, our acronym for black indigenous and people of color generally. So they're really thinking about who's there and they look in the classroom, because pretty much by this point all of my students have outed themselves with disabilities, even the ones who aren't officially declared with disabilities at the university, or who were just diagnosed as I was in PhD school. So there's been a lot of talk about doing this and support we heard the students say we need support to learn how to do this and that panel. So I do three guidance documents for drafting a syllabus and the support is there. What resources to use how to use them what to look for both in terms of the syllabus, and also the accessibility skills, and they do those some practice assignments where they try things out along the way by doing these drafting along the way. And this is, you know, one of the ways I start to talk to them about it is you start to do it you learn and apply the core skills. They apply to syllabus texts in these particular ways using headings hyperlinks margins and white space. I actually do turn back the first time I get a syllabus draft that has margins smaller than an inch all the way around, and does has single spacing because that's not visually appealing. So my question to them about visual scan matters as much as a screen reader scan, your eyes need to move and there need to be cues. So we have some consistent texts and they know that from the beginning, and they've already used them for some assignments. It's contract grading so my students I used to have the last be item listed as the a item for a grade that had to use the core skills. The class has said no. No, everybody needs to create an accessible syllabus document and use those skills and think about what it means because everything we do in our career means that we know how to do an accessible document going forward, especially if we're going to be able to do that in a formal form build on it. So they helped me to revise this and have it being that they have to also use principles of teaching with access and inclusion in the design of the course and reflect on that reflect that in their document and talk about it in their self assessment tool. So I'm going classes and say what do you think about that and they all very happy because they can take out stuff in their portfolios that nobody else has. And they can also go back to their departments and have some leverage for saying to their faculty, I need more accessible materials accessible materials that are more accessible. So, faculty get changed get prompted to change because of their grad students. So one other thing here then is this is a quick look at the memo that they do several items, but the part on accessibility is they have to do the like scale but also really think about this what do you do and that ends up being the last narrative question they give themselves a grade. They talk about a comment about the grade they talk about the strength of their syllabus where they're working on next and then they do this. The grade and the comment on the greater one item. And often when they get to this part they've given themselves and a because they've learned how to do an accessible syllabus. And if they hadn't they think they wouldn't be passing B is you know barely passing for a graduate student in the US. So these have been really self revelatory for them in a lot of ways to. So finally, you know I'm going to come back to Alistair that's not only about expertise and technology or disability it's about expertise and communicating without barriers and one of the ways I've been able to work on this is. We do have a village of people who are interdisciplinary in diverse. They're inter campus all of our campuses work together, they're inter professional and that has made a big difference because we're not specialists it's not limited to specialists we all learn how to do it. And it's about communicating without barriers becomes the piece that students take back to their faculty and to their own students when they say, now here's how you're going to do your assignments. I have three former students I continue to work with and co writing and co teaching, and they all have their students do the same production of accessible materials. That feels like a win. And then even more in this it's really that thing of a climate where the networks of accessibility inclusion are really important peers create accessible materials for each other the learners and the teachers. The learners in their learning spaces we try to figure out how to do accessibility in the spaces, and also what if the resources I'm providing them aren't fully accessible. A web page is not my friend Collette's favorite thing. I turn them into Google Docs and get permission to do that so he doesn't have to navigate the ads. The recommended articles are not my best friends favorite thing on a chronicle of higher education page because he's ADHD and he'll go into each and every one of those rabbit holes. But with a Google Doc he doesn't he stays where it is and he can because I leave the other articles at the bottom. He can choose to go there. So, this is just a first page of my own current syllabus as I go into the next semester, which started on Tuesday this week. And it's a place where I try to walk the talk and that's available to you as well for taking a look at what we do in this teaching and higher education course. This also the other one called teaching for learning, but for making it open educational materials the part is, what can we do to down platform so that people have the skills so they can up platform, and I've been really happy with how they've thought about accessibility when they move to, you know, prettier versions of what they're doing. So that's it and me talking really fast. Where is questions, conundrums, experiences, challenges, anything like that. So, which was a simulation of a Thomas lab space. And at the end of the time, personally, basically, I'm just taking this memory as a turn this into a new chapter as well. And the academic commission that is now asking for us to release it as a real step. I've done a lot of work in the last years around accessibility and I'm going to say this, but it wasn't designed. And we have the SBIR in 2018. So that's the public services body of accessibility regulation. And I think that we look at or change. And that has to be recreated in an accessible way. And part of the thing is, is this the right, as much as we may want to do it. It's a chunk of work. It's a piece that would need a complete redesign, reimagining in the structure, those different elements, the base parts to be accessible by design, then build that in chip and code. Is it the atomic structure of learning? You know, you have to start with accessibility, so those bits up. And what you were saying about the down platform and the up platforming, it feels like... Makes your head want to explode. Yeah, but I think that's because I appreciate the volume of work that would be required to turn that into an accessibility. I think that's what it is. I'm sorry to interrupt. That's all right. I'm just going to give you my prejudice. Because I can't spread to you. I can't spread to you. It's not because I don't find it interesting, it's like we're here, not because I don't think so. I do wish you well. And I have a different feeling. Well, you're still here for a minute. I mean, one thing that I've... So I'm redesigning our website on course design, and it's going to be course and syllabus design, and it has to model the accessibility stuff that we've been talking about. And Charlotte, the woman who's doing the web part of it is a little alarmed about how to do that. So one of the things... Because our web pages do not print out pretty. No matter what she's tried, the Drupal format, the US pick just do not print out pretty. Things overlap and... So our small changes for all the pages that are core ideas, there's going to be a click to a Google document that will be instead of at the end where it says, you know, you can put the word... Where there's edit in your version, you put the word copy in, and then you paste that URL in, which makes them download it to their own computer. So we're going to do that for everything that we think is foundational. Because we can't do it all right now, but everything that's foundational. And if they have a diagram... Right. Right. Right. And if we have a diagram in there, that can be in there alt-texted in a way that someone who's not using an alt-text reader. So me, I like checking the alt-text out because I usually learn something more. I can do that too. So that's our first small step is to say, what's foundational here that we need to make that available as a Google doc and download so they don't mess with it. So it will live in a unit space, not in my computer. They'll take it on so that when I leave, it doesn't leave with me. Yeah. Thanks, Sue. Sorry. I'm sorry. I'm sorry. I'm sorry. I'm sorry. I'm sorry. I'm sorry. I'm sorry. I'm sorry. I'm sorry. I'm sorry. I'm sorry. I'm sorry. I'm sorry. I'm sorry. I'm sorry. I'm sorry. I'm sorry. I'm sorry. I'm sorry. I'm sorry. I'm sorry. I'm sorry. I'm sorry. I'm sorry. I'm sorry. At least we have the door that works. Yeah. The force is it? What am I already faculty? No, it's all graduate students. Unlike a PG or cert where it might be faculty. It's all graduate students and some post docs. of weeks for the online course design. Is this going to be teaching? No, well, they want to be teachers in faculty life. Yeah. Yeah, and some of them are also taking it because they know that in mentoring, they're actually teaching. So we have a school of public health and a plant biology program that required everyone who's a graduate student, whether they're gonna teach or not because they are going to be mentoring in labs and because they're gonna be teaching undergraduates how to do the lab work. So they're required to do it as well. And we also get a fair number of international students who are learning how to teach in the US context and wanna take those practices home and often they're the ones who are most welcoming of the inclusion and the accessibility pieces because they feel so excluded at home, sometimes unsafe at home. So they wanna learn how to do things here to feel safe and so their students can feel safe. So it is almost all graduate students. And it's tuition-driven and they have a tuition band as we call it until they do their, pass their exams until they become ABD. So right before they write their dissertation all that time period, they have a tuition band that's available for them to take courses. So for the most part, it's paid for through their programs and the one credit one that you have the syllabus for is our compromise for when people are, at the end of that there's usually just like one credit left. So we did that to get them in. Faculty also have a program called Early Career which they attend. When I did it was six big sessions, it's now four because of being online and then they meet with peer groups six times and do some of the same work. So we're trying to get it there and we're trying to get it into the things our academic technology department does as well. We're there, they feel a little less confident telling faculty what to do. And we don't at the Center for Teaching just because I think because we're teachers too. Yeah. So in terms of the content, when you go to the Google Docs and everything else do you have, I wanna call it like a safety check on the plane like a process should go through just a double check or be aware of bits and pieces before you then decide to share it out into the world like license checks or is that can all happen before? So for the syllabus is that we share as examples like that and we do the permission thing and I'm working on that right now to get permissions for sharing them out in the world and most of the graduate students I'll very few of them do the thing of saying please don't share this within the course, courses you teach because it feels very much like a peer to peer even though they're not in the same section so they're good with it being shared across sections and I always have to put in a note that says you have permission to use this and you can show your print version to somebody if you wanna do that or show somebody your screen and you do not have permission to share this in any public space and I'm gonna have to trust you on that so we don't have an open license on those we haven't done anything with that because there isn't really one that says yeah you can share it but not outside this circle so I've done it that way and we will put all of the stuff that we're working on like when I finish the public facing course it will be all attribution and everybody will have given permission either for a whole syllabus or a segment and within the course then too they work in small groups and they agree to share with that but beyond their small groups they let me know if they're willing to have other people look at their syllabus even in the course what I notice with grad students there's not a lot of protective they're not protecting their intellectual property in the same way faculty are they want it open access and they want open access publication and they want that piece and for them to say I have a couple of undergraduates who's stuff I'm including and that's huge for them too my material is featured in this resource it's a good thing we're digitizing our what they call content release so they're going into a much easier format to use that is digital and we're looking at what we need to look at in the detail where the creating common structure starts and I forget it I'm moving something else there yeah and I have to get ours approved by general council so that's one of the things that slowed me down I was hoping to have the site done it's like oh right I have to go to general council to make sure that my form is correct we've never had to do that before but because it's the provost office our registrar's office they want to make sure that it's but it's also like IRB I want there to be a fast track for the legal stuff as there is for institutional review we have a fast track and we always get fast tracked but not the legal stuff thanks for hanging out


Sequences are stored in different formats in databases and since different softwares they require those sequences to be in specific format so it's good to have an idea about what the major formats are and we will go on few of them. FastA is the most recognized and well-distributed format so normally in FastA the sequences they are put in there is a greater than sign and then down below there is the actual sequence so the length of the sequence should be less than 80 characters. Generally we have it's around 60 characters so here is the FastA format coming out from DNA at the top we see it's starting with this greater than sign right here same way down below is the protein and then we have GIGI stands for gene identification obviously this is the idea of this gene and then there is something written as C so C is it's coming from actually the complementary stands and the regions from which it's coming are designated here the base positions in between them this gene is located so and then there is a short description that it's coming from Homo sapiens man chromosome 17 this is the assembly primary assembly so assembly is where we can get short sequence reads or small sequences and we put them together into a gene so that thing is called as assembly so it's a primary assembly so then here is the actual sequence that starts so it's around 60 base pairs in each line and since this sequence was very big so I put those dash in the end we can also see a protein sequence over here down below same way we have the ID then it's a reference sequence so reference sequences are the ones which are the curated sequences there is a subsection in NCBI called as RAF6 so that actually puts those references kind of standard sequences in order to avoid redundancies so we can say these are the primary or the main sequences we might have other alternative slice variants but references are kind of true representative of the class then we have this ID again right here the protein ID then we have its description its cellular tumor antigen protein p53 isoform and then we put it sequence so I excluded some part of it so those dashes are there so sometimes it fastifies they end up with this star signs sometimes they don't so it's important that the software must know that what star means here so gene bank is the format which is there in the gene bank database so that's kind of a standard format the other formats are pretty similar to it in gene bank the records they start with word locus and then we have some description lines the sequences they start with the word origin as we have seen previous in previous sections and sequences they end up with those double slash signs so here is the gene back format so we start with locus and then we have its ID it's 237 base pairs there are there are some short descriptions its DNA its primary sequence submitted on this date then we have a definition line where we can have some descriptions some explanations about this gene again we have accession number and then it provides the base counts also how many is in it how many sees in it there are how many G's in it and how many T's in it and then the word origin tells us that the actual sequence is coming so actually we have these lines in which we have 60 bases and they are split into chunks of 10 so that is kind of a standard practice and sequences end with those slashes now ample format is similar to gene bank format we have ID we have accession we have descriptions represented as DE and then the sequence actually starts from where the word sq is there and then we have pretty similar line as we have seen in the previous example and then the sequence ends with double slash is just like gene bank uh Swiss plot is similar to ample except there are some more descriptions there are some more letters so we have plenty of them you can go and to look into it for example we have rp reference position our n reference number rp reference position and then we have authors who have submitted and same way the sequences they start with sq and the termination line is this represented as this double slash so far what we have seen is those sequences are submitted in kind of similar formats um xml is a modern practice in which we try to put those sequences in kind of a machine language so xml stands for uh extensible markup language the format is similar to htt html which is the language for web programming um the the good part is that this language is in between uh machine and man readable so this kind of easy to code over this so that is seems like pretty weird but not weird for the people with the computer science background so it's kind of this format nbrf uh let me go over it also it gives uh these in addition to the sequences which are format is pretty similar to simple fast a but in addition to that it gives us the checksum value so checksum is we take those nucleotides and since we know in computers every digit is related with some ascii value so we can take those values and add them up together and then we can come up with this number called checksum so that is good to uh put there and once somebody is downloading the sequence he can again check on his computer and find the checksum if they are they are they are equivalent to one another if they are equal to one another means the sequence is uh correctly downloaded otherwise there must be some issues with the downloading gcd stands for genetics computer group so basically it's a group of scientists who were helping the biological community to develop the softwares and training programs to help with the biological sequence analysis problem so this uh also came up with those format sequence formats which are kind of similar to the previous one nbrf we have checksums we don't have greater than sign just like fast a they also tell about the length of these sequence and then there can be multiple sequences in one file uh sometimes we need to convert between different sequences so you can come up with your own scripts or or you can come up with your own codes but there are some other programs which are available so one of them is Reedsick so that was developed by D.G. Gilbert at Indiana University and basically it recognizes DNA or protein sequence files and then it interconverts between different formats so what we can conclude from this section is that databases they store sequences in different formats and since we need to play between different formats we might write our own codes or we might take help from the already available programs like Reedsick


Let us have a look at how we estimate the research, development, testing and engineering or RDTNE cost and also the aircraft production cost for a given amount of production run. We have taken Boeing B787-8 Dreamliner as our test case for this exercise. We are going to follow a color scheme in this presentation as always. The general instructions are going to be given in this brown color, if there are some values which are specified in some sources, we would show them in black color. The values which are assumed are shown in this light blue color. The places where you need to do some calculations will be shown in red color and there will be this symbol which represents a pause button. Wherever you see this symbol, you are expected to pause the video, do those calculations and only then proceed further. I would like to reiterate that you will learn aircraft design only when you do calculations. Just by looking at the videos and nodding your head, you really will not be able to appreciate and also get a firsthand feel for doing conceptual design calculations. The values which are calculated will be shown in this dark blue color and towards the end we will compare the value and the color green will be used to show the quoted values. The procedure that we follow is based on the cost estimating relationships or CERs which are outlined by Daniel Rehmer in his seminal textbook. We have used the Rand modified Dapka 4 model of 2012 which has been mentioned by Rehmer in the sixth edition of his textbook. Note that the values that this model predicts is for 2012. So therefore, we have to scale up the cost from 2012 to today 2020 using some inflation factors. And for inflation factors we have referred to an online source. There are also some assumptions which have been made while carrying out this analysis. The Dapka 4 model does not have any way of predicting the cost of avionics. So we need to assume some weight of avionic equipment onboard the aircraft and the cost per unit weight of those items. The engine used on Boeing 787 series is a very advanced engine, it is a turbofan engine, high bypass HO and it has several features like Chevron etc which reduce the noise etc. So the Dapka 4 model gives you the estimation of costs based on the some parameters related to the engine such as the turbine inlet temperature and the maximum weight etc. But we have increased the values by around 20% as suggested by Rehmer for a turbofan engine. And finally there will be an assumption that 10% of the costs are going to be added towards the return on investment and another 10% will be required for the initial spares which are supplied with every aircraft. So whatever cost we estimate it is going to be scaled up by a factor of 20%. Let us look at some useful data for Boeing B787-8 aircraft. The aircraft data, so empty weight is as mentioned 236032 pounds. The AMPR weight is the aviation manufacturers planning report. This weight is assumed to be 62% of the empty weight. So it turns out to be 146340 pounds. This is an assumption because 62% is an assumption. The weight of the electronic items in the aircraft is not known. So we have taken a suggestion from Rehmer, we have taken the value. So Rehmer suggests the value to be between 2000 to 6000 pounds, we have taken a medium value of 4000 pounds. The maximum speed of the aircraft as listed in the specifications is 426 knots equivalent at speed, hence it appears in black. The maximum thrust per engine as mentioned in the Gen X engine bulletin is 69800 pounds. Gen X is one of the choices available for the engines for Boeing 787-8 and in the same specification manual, the turbine in the temperature is mentioned as 3150 Rankine. As far as the material is concerned, Rehmer suggests the value of up to 1.8 for the graphite epoxy composites. But we have taken a slightly higher value of 2 because there is very aggressive use of composites in Boeing 787. As you know, the most of the fuselage is consisting of composite material unlike other transport aircraft where the fuselage generally is aluminum alloy. We have to also assume some production related data. We have to assume the production run. So we have taken the number as 1100 aircraft. This is based on some websites where they discuss about the plans of the company. The rate of production of the aircraft is also assumed to be 10 per aircraft. The same number is used in the RDTNE phase as well as in the production phase. Because in RDTNE phase actually the fabrication of the aircraft is a kind of a almost like an individual hand-built prototype in some ways. So therefore we have assumed that even the rate there is also 10 to bring in a little bit higher cost. And we assume that there are 6 aircraft to be built during the RDTNE phase. All 6 of them are going to be subjected to flight testing. And then maybe 1 or 2 of them will also be used in the structural testing. Some of them may actually be completely destroyed. There may be destructive testing. For example, the wing of the aircraft is generally tested to destruction. I think even the fuselage some areas are checked for rupture loads during pressurization etc. But we assume here that all these 6 aircraft are to be costed in RDTNE phase. And they will not be sold to any manufacturer. They will be available with the manufacturer for any further exercises. The manoeuvre rates specified by Rehmer in his textbook are as shown for 2012. And these have been increased based on an inflation fraction from 2012 to 2020 using an online inflation calculator called as USAinflationcalculator.com. As per that the inflation factor from 2012 to 2020 is 1.117. So all these costs are scaled up accordingly. The avionics cost as mentioned by Rehmer is 6000 per pound in 2012. This also has been scaled up using the same inflation factor as 6702 per pounds. Let us look at the first and the most important component of the cost that is the airframe engineering cost. In the RDTNE phase, the hours required for airframe engineering can be estimated using this particular cost estimation relationship in which empty weight, maximum speed and the production rate per month are the quantities to be used. So we are using F material as 2 because we are using graphite composites and more advanced versions. So at this stage you should pause the video and do these calculation. The number comes out to be 4.37 10 power 7 hours. This number is for the hours needed for the airframe engineering and the manoeuvre rate for the airframe engineering is already mentioned in the previous slide is reproduced here. So the cost of airframe engineering in RDTNE phase would be a product of the hours required and the manoeuvre rate. So please pause the video and do this calculation. The number comes out to be 5.76 into 10 power 9 which corresponds to 5760 million or 5.76 billion US dollars. The airframe engineering cost for production is obtained by the same formula as shown here. So when we look at the production aircraft, the number is 1100. So I think you need to have a look at this and pause the video and calculate this number. The number turns out to be 1.022 into 10 power 8 hours. Now we know that the cost inflated figure for the engineering manoeuvre rate is 131.81 per hour. So the cost of airframe engineering in the production phase would be the product of the hours needed and the rate per hour. So putting in the numbers pause the video at this stage and calculate this number. The number turns out to be 13.47 10 power 9 or 13.47 billion dollars. The tooling cost in RDTNE phase can be determined by the expression in terms of the empty weight, the maximum speed and the quantity produced. So again putting in the number for RDTNE phase there are only 6 aircraft produced, the maximum speed and the aircraft empty weight is already known and the factor 2 takes care of the material. So this number turns out to be 1.943 into 10 power 7 hours. The cost inflated manoeuvre rate is as mentioned. So therefore the cost of tooling will be the product of the hours required and the manoeuvre rate this is as shown in the screen. So at this place you should pause the video and do this calculation. The number comes out to be 2.495 into 10 power 9 or 2.495 billion US dollars. Look at the tooling cost in production phase, the formula is the same. The only difference is that now instead of 6 we will use 1100 which is the quantity produced during production. So once again pause the video and do this calculation turns out to be 7.649 into 10 power 7 hours. The tooling manoeuvre rate is as mentioned, multiply by that rate to get the value of the cost of tooling and that would be 7.649 into 10 power 7 into 128.46. Please pause the video and do this calculation now. The value comes out to be 9.826 billion, manufacturing labour and quality control. Now what we have done here is that we have actually included a factor of 13.3 percent in terms of 1.133 for the quality control costs because what we have done is the manufacturing hours are going to be increased by 13.3 percent to take care of the quality control hours and we also assume here we make a slot departure, we assume here that the cost of the manoeuvre rate for the quality control is the same as that for manufacturing labour. This is because the in reality the costs are slightly higher. However in the interest of ease of calculations we have just assumed this cost to be the same. So this number is slightly to be slightly higher then the number is going to be slightly lower. So the number of hours are going to be correct because the factor is included. However we multiply it by the manufacturing labour manoeuvre rate and we get the total cost of manufacturing as 2.514 into 10 power 7 into 109.47. So let us see what number is there. Please pause the video and do the calculation. The number turns out to be 2.751 billion. In reality what you should do if possible is that calculate the hours by using the using only 0.133 here but when you multiply by the manoeuvre rate for the quality control you can use a higher rate of around 120 odd dollars. So that way you will get slightly more cost for the quality control but we have assumed that the 2 are same and made it a bit simple here. Similarly for the quality control and the labour cost during production the formula remains the same the only difference is that you have to insert 1100 here instead of 6 which was there earlier. So please do this calculation by pausing the video and then you can compare your numbers with the value obtained by us which is 7.097 into 10 power 8 hours. In other words if we now assume the same manoeuvre rate for manufacturing labour and QC which is simplification as I mentioned then you can get the value for total cost of manufacturing labour and quality control in production would be 7.097 into 10 power 8 into 109.47. Please pause the video here and do the calculations. The value comes out to be 7.7683 into 10 power 10 or 77.683 billion very large amount of money is needed for manufacturing labour and quality control in production. Let us look at the manufacturing material cost and we will look at both the RDTNE phase and the production phase together because it is just one equation the only difference being the number of aircraft produced. So the formula is the same for both only thing is that when you calculate the manufacturing material cost for the RDTNE phase you use 6 here and this factor takes care of the inflation from 2012 to 2020. So this number turns out to be 1.963 into 10 power 8 billion sorry and then it comes out to be 0.1963 billion similarly when you do this calculation again pause the video and do the calculations you put 1100 here instead of 6 everything else remains the same do the calculations please. The value is 12.626 billion. Development support and flight test costs are incurred only during the RDTNE phase. So there is a formula available for the development support cost in which we have inserted factor for inflation. So these two are the parameters which are already known and this is an assumed inflation factor please calculate the value it comes out to be 648.2 million or 0.6482 billion dollars. Similarly the cost for flight test is available in terms of the empty weight maximum velocity and the number of flight test aircraft. So we assume here that all the 6 aircraft which are made during the RDTNE phase they all are used to undergo flight testing so hence excuse me we have put the value 6 here. So please calculate this number turns out to be 197.2 million or 0.1972 billion dollars. Again this cost is incurred these two costs are incurred only during the RDTNE phase. Let us look at the engine production cost. So the cost of the engine is available through a formula in terms of the maximum thrust, maximum mark number and the turbine inlet temperature and N for number of engines which we know is 2. So I would suggest that even though there is no pause button here and no question mark you should actually pause the video here do this calculation and determine the value of CEP. It turns out to be 25.25 million dollars in 1998. This formula was available for 1998. So if you use the inflation ratio from 1998 to 2020 as given in the same source then the factor is 1.573. So if you scale up the values you get 39.72 million. And remember as per remember suggestion turbofan engines have around 15 to 20% higher cost. So we have taken the higher value of this 20% higher cost. So the cost scales up to 47.661 million. So since there are 6 aircraft each of them will cost 47.661 million. So because the number of engines is already included here so this is the total cost of the 2 engines which is scaled up to 2020 values. So we go for the calculation and we get the number as 0.286 billion for the RDT any phase because just 6 of them have engines. But if you go to the production phase it is 52 billion dollars or more because there are 1100 aircraft to be produced. Quite a big cost. Avionics cost. As I mentioned we do not know the mass of avionics and we do not know what is the cost per mass per unit mass. So as per remember suggestions the avionics weight of a typical transport aircraft varies between you know 2000 to 6000 pounds. So I have taken a value of 4000 pounds. So therefore the cost of aviation is supposed to be 6702 into 4000 which turns out to be 26.8 million per aircraft. And therefore the total cost in the RDT any phase would be 6 into 26.8 million because there are 6 of them produced it is 160.8 million. And during the production there are 1100 aircraft so the cost will be 29.48 billion. There are a couple of other cost factors we have to consider which may not be some of them may not be very very prominent. For example every aircraft has a interior, cabin interior and that costs some money. So suggestion by Ramer is to assume 3500 dollars per passenger and that too it is the number given in 2012. So the RDT any phase interior there will be 6 aircraft and we assume that there are 10 seats in every aircraft just an assumption because very few people go when you actually go for flight testing and this is a escalation cost escalation factor or the due to inflation. So calculate this number please it is a relatively small amount of 0.2346 million dollars. But in the production cost this is going to be a much larger number because the multiplying factor is not 6 but 1100 and the number of seats is not 10 but 242 which is the maximum capacity of Boeing 787-8 as specified in the manual. So therefore this cost comes to around a billion dollars. Now we also assume that the company that makes the aircraft which is Boeing would like to get some return on investment that we assume to be 10 percent and the initial spares cost of the aircraft is also 10 percent. So we will scale up the cost by 20 percent to take care of the fact that some initial spares have to be used. So let us look at now how all these costs are put together in a straight table. So here we see all the 9 sub-components of the flyaway cost and then there is a sub-total both for RDTE and production over that we add 10 percent each towards the return on investment that is the profit for the company and spares initial spares that go with the aircraft to get the grand total. We see that the RDTE cost is approximately 15 billion dollars and the production cost is 235 billion dollars. Let us look at the breakdown of the RDTE costs. So in the breakdown we observe that the largest component is of the airframe engineering cost followed by the cost for manufacturing labor and quality control and equal weightage for the manufacturing material and the cost of tooling. So these together correspond to approximately 70 percent or more. In fact much more this is 25 percent and you know so around 80 percent of the costs are because of this in the 1890 percent and remaining all costs come under these small pies. There is a breakdown of production cost in billion dollars. So now in the production cost we notice that the largest component is the manufacturing labor and quality control as expected followed by the airframe engineering and the tooling and avionics. These are the major components and everything else corresponds to the remaining. So let us now estimate the unit flyaway cost. So we have seen that the RDTE cost is approximately 15 billion dollars, 14.99 to be precise. The production cost was 235.86 billion. So together the total program cost turns out to be the addition of these two costs which is 250.857 billion dollars. Now the unit flyaway cost would be the cost of the total program divided by production run which means it will be 258.57 million divided by the number of aircraft sold which is 1100. So per aircraft it comes out to be 228 million dollars whereas if we look at the list price of Boeing 787-8 in one of the online sources. We see that the quoted price or the list price is 224.5 million dollars. So the difference is only about 1.6 percent. So we have obtained just 1.6 percent higher cost the quoted price is 1.6 percent lower. Before I close I would like to acknowledge Daniel Rimmer for his seminal textbook on aircraft design which we have followed in this tutorial for all the formulae and the calculations and Namanuddin for help in creating this tutorial. Thank you for your attention.


We can use message authentication codes to perform the service of authentication and data integrity And we went through a few examples Basic idea is that we take our message and we calculate the Mac of the message Using some secret key shared only between the the source and the destination and the Mac We sometimes the output we call a tag or even just a code or a message authentication code the Mac is Attached to the message and sent and what the receiver does is checks Verifies the received message by comparing the Mac of the received message with the received Mac Okay, that is we receive a message plus the tag and And the receiver verifies by calculating the tag for the received message Comparing it to the received tag and they should be the same Because the nature of the Mac algorithm should be such that Two different input messages with the same key will produce different outputs different tags So if the message is the same as the original then we'll get the original tag back So the verification takes place there the other two diagrams here are just combining the Mac with encryption the first case The data is not encrypted so someone can see the data It's just authenticated the second two cases are the data is both encrypted and authenticated And the difference between them is the order in which the Mac and the encryption is applied in the the middle diagram Calculate the Mac and then encrypt in the bottom diagram encrypt and then Mac and If you see how for example secure shell works And if you capture some secure shell packets some of you have done that in a lab Then you'll see that a common form of a message authentication use is the bottom one of encrypt and then Mac Okay, that is you encrypt the the data first and then calculate the Mac on the ciphertext But the difference between those two is is not significant in encrypt and Mac or Mac been encrypt There are subtle differences, so there are some recommended approaches, but we will not go through them Both are considered secure in general cases, but there may be some specific cases where one is better than the other Commonly encrypt then Mac is used and we got to where Let's look at the security of Mac's just briefly talk about How someone can try to attack a message authentication Code algorithm We had some examples where the idea was from the attacker. I think we have one here The malicious user Tries to modify the message So and this was the case where the malicious user intercepted the message and the tag that was sent They changed the message But not the tag They send it on to be hoping be will think this is the real message but because of the Message authentication code was used be calculates using the key shared between itself and a on the receive message Using the Mac function and gets a calculated tag compares it to the receive tag and They will be different And in that way be detects something's gone wrong and doesn't trust the message and We covered a few other cases the other possible cases and we see that assuming that the algorithm Will produce produce two different messages with Well two different messages will produce two different tags or Using two different keys will produce two different tags assuming those rules hold Then the attack will be unsuccessful What about brute force attack? What can the attacker do and I'll bring up one of the other cases that we considered I think we have it here This one This didn't work for our attacker. What could they try to do in a brute force attack? How can the attacker make a change such that the receiver be doesn't detect the change and In a brute force attack, how could they do that? What do they need to do? What was the problem in this case? What could the attacker not do? They didn't know the key Okay, so here they changed the message. They modify the message. They want to Recalculate the tag of that modified message but They don't have the key that B is going to use to check B is going to use the key shared between itself and a Their attacker doesn't know that so must use some other key Well a brute force attack try and guess the key That's the basic idea here if you try and if you could find the key Then you can be successful in attacking because if if the malicious user did know KAB They could use it here and send the message and B would not know the message was modified so one approach from a brute force perspective is Try all possible keys And we'll do a little bit of analysis and see that approach so The security of a MAC algorithm with respect to brute force one thing it depends upon is the length of the key To stop a brute force attack on a key make the key long That's our general rule. So the key must be of a reasonable length more than a hundred bits most likely But there is another way that the attacker can try and attack and that's to try and guess a tag Even without the key Let's see if they can find a message that produces this They if they can find two different messages That produce the same tag They can be successful in an attack as well because we said that The success of the authentication depends upon the fact that two different messages produce two different tags That's what we depend upon but we've also said in theory Because there are more possible messages than tags Some messages will map to the same tag So the challenge of the attacker is to find Two messages that produce the same tag. Let's See the the concepts and then go through an example So in terms of the an attack we assume that the MAC function is known They they know what the algorithm is. They don't know the key And I think there's a typo here instead of four should be fine They want to find a valid MAC code for a given message X They not for find valid MAC find a tag for a given message without knowing the key If they can do that then they can defeat the authentication schemes So it should be hard for an attacker to find the tag without knowing the key and One way to state that is computation resistance that is if the attacker knows multiple one or more pairs of some message X here and The tag of that message so the MAC of some key of that same message if the attacker knows the tag and the message And multiple pairs It still should be hard for the attacker to be able to find that The tag for some other message That is if the attacker has some message X It should be hard for the attacker to find the corresponding tag That states the requirement here so given the message you can't find the tag unless you have the key of course But the assumption is we don't have the key Even if we've seen other tags and messages used with the same key We will not go through a proof for the details of the the security, but just quickly state the approximate strengths of message authentication codes. There are two brute force attacks Try and guess the key or Try and find the tag or the MAC value without knowing the key and there is some So for example brute force attack on the key the attacker knows for example some message X1 and the corresponding tag Where that tag T1 was calculated using a key on that message the attacker doesn't know the key a brute force attack try all possible keys So the attacker knows the MAC function they know X1 they take The first possible key calculate the MAC Get a tag if it produces T1 Then potentially they've found the correct key if not try another key, so they try all possible keys In this function here key one with X1 Look at the output if it matches the known T1 Then that's a possible key if not ignore that key and Try all possible keys the number of attempts if we have a key of k bits is 2 to the power of k so if our key is a 100 bits long they need 2 to the power of a hundred attempts to try all possible keys There's for this attack to be successful Usually the attacker may need to try with multiple pairs, but that's not so hard. That is that may be that Multiple keys will produce the correct tag in which case the attacker needs to try with a different pair of message and tag and The pairs that produce the use the correct key the same key will give us the answer The main point is that a brute force attack on the key depends upon the key length and Approximately the amount of effort is 2 to the power of k worst case that is if I need to try all keys and the keys k bits long I need to take 2 to the power of k attempts and A Mac function is usually in terms of computation on your computer is in the order of the same time to do an encryption function So 2 to the power of 100 attempts we've seen in brute force on symmetric key encryption 2 to the power of 128 is going to take billions of years 2 to the power of 64 may be possible So usually anything above 80 90 or 100 bits is is going to be secure So make the key long enough to avoid a brute force attack on the key Let's let's kind of see this consider a simple example. I Don't have a real Mac function, but I have a fake one that we can use with small values Let me see what we can do. I have a fake Mac function that will use and The parameters of that are that in the first instance We have a key of The key is three bits the Mac function takes the key is input and a message and produces a tag where the tag is in The first example I'll show is four bits and the message In my simple Mac function, I will show you is limited to eight bits So this is not a realistic Mac function. It's just a simple one to demonstrate the numbers in a brute force attack so Every message as input is fixed at eight bits and when we take the Mac of a message using a three-bit key We get a four-bit tag. How many possible messages? Which is two to the power of eight is 256 possible messages different messages with eight bits and How many possible tags? 16 possible tags. Do we have collisions? What's a collision two or more messages mapped to the same tag So they're 256 possible messages If we use the same key We can get 16 possible tags as output This is the input which implies that Some messages must map to the same tag There's no way that Applying the Mac function on two different messages will always produce two different tags because we don't have enough tags for each of the messages And that's just that's the same in the general case with a Mac function that the number of tags is Much smaller than the number of possible messages. So when I say collisions, I mean two different inputs produce the same tag as output in Theory possible and definitely in this case quite easy On average how many Messages map to the same tag.  So you're experts on statistics and probabilities, especially On average how many messages produce the same tag 256 divided by 16 on average if we have random mappings So 16 Messages mapped to the one tag on average if it's random and a Mac function should be random That is it takes an input and produces a random output. So for a first example, I'll Say we have The attacker knows a tag the tag equals in my example shows They know a tag and they know the corresponding message So for example in the past a user has taken that message those eight bits Use the secret key K and obtain the tag one one one zero the attacker has intercepted them The attacker now wants to find the key What do they do? How do they find K in a brute-force attack? What are you going to do? Try all possible keys in the Mac function that is with that message M Try the first possible key. Let's say zero zero zero and To calculate the Mac if it gets the tag one one one zero Then we're on track if it doesn't try another key Now the example I'll show is again not a real Mac function. It's just one to to give some example numbers as output Let me find it So we've got a tag just remember one one one zero and a message What I just wrote and I've got a Mac function that that takes the message and a secret key I'm not going to tell you the secret key. It's secret and it produces a tag So I've got something that will try all keys on that message Basically what this function does is tries key zero zero zero Using this message and calculates the tag and we'll see the output then it tries key zero zero one on that message Gets the tag and does it for all keys. How many keys? Two to the power of three eight keys in our case There are eight possible keys just to keep it simple You tries all the keys it gets the tags. What's the key? Do you think? There was my brute force attack. I'm the attacker. What's the key? What I what this code did was took this message tried Key zero zero zero and it produced the tag one zero one one. I Know if that message uses the secret key it should produce this tag So this is not the right key So I try zero zero one. It doesn't produce the expected tag. We keep going and what do we get? 101 Okay, so in this case we've found the key is 101 Because that key with the same message as what we know produces the expected tag So that's the brute force attack on keys Now in some cases it may be that Two different keys produce the same tag If that happened then we'd need to try it on another known pair So in this attack the attacker knows the pair of tag and message just one pair If two keys produce the same tag we'd need to try those two keys on a second pair Which wouldn't be hard? How many attempts? Dot slash means run the program which is in this directory Dot means this directory slashes a directories separator. I'm not going to go through the Mac function I'm just trying to illustrate the number of attempts it takes Try all keys is just my own function that tries a Mac function on all possible keys On average or worst case. How many keys do we need to try it? In this case we took six, I think Worst case how many keys with this algorithm eight So in the best case I find it up front in the worst case it takes all eight on average It would take four so worst case is eight in this case In general two to the power of K K is the key length in this case. It's three So that's one attack from the attackers perspective in this case It made sense to attack the key the key was three bits it That was the weakest part of the algorithm but another example Same algorithm, but slightly different parameters Let's say in a second case. We have an algorithm that takes The key is five bits The tag it produces is four bits still and the message is also eight bits brute force attack on the key How many attempts worst case? 32 to the power of five okay five bit key. We need to try 32 so we could do that But let's look at it Excuse me a different attack. Let's say we know The attacker knows some tag Or they want to generate some tag and it's zero one zero one that is In this attack the attacker wants to find a message That the other two users when they use their shared secret key the attacker doesn't know the key They want to find a message that produces this tag That is with some key Which is secret? We don't know that we want to find the message that will produce that tag So that we could defeat the authentication schemes because if we can find a message that produces the same tag of another message we can Make changes without the receiver notifying are being Being aware This attack is slightly more complicated or it relies on some different assumptions And the assumption is that the attacker can somehow ask the user to Apply the Mac using their secret key on different messages So let's say the attacker knows user a and Somehow they can get user a to say oh here's a message. Please calculate the Mac for me So the attacker sends a message to user a and and says calculate them the Mac user a does it using their secret they don't tell the attacker the secret and The attacker learns the tag So there's some sort of way that there's some sort of service that allows the attacker to Find the Mac of a message without knowing the secret So what the attacker can do is try some message some random message Ask the user to calculate for that message using their secret key the Mac when we get the tag If it matches the tag that we want Then the attacker has found the The message Let's try that and see how that helps the attacker So again, this has a key of five bits the key is secret. We're not trying to find the key We're trying to find some message That when we use with that key will produce the tag zero one zero one my attacker again The tag zero one zero one What the attacker does is Contry random messages What the attacker does is chooses a random message some message Sends it to the user and the user will calculate the tag of that message and The attacker learns the tag if it matches zero one zero one Then the attacker is successful because I've found a message without knowing the key that maps to the tag that they want so this program all it does is Calculates for random messages the tag with the secret key and prints them out and the way that it works is that it stops once it finds that tag so in this instance what it did was given this random message and the key that we don't know but We got the user to calculate the Mac with their key and we found out the tag is one zero zero one That's not of use to us. We want zero one zero one so we try another message and We get zero one one one. No, we keep trying until We get zero one zero one now the attacker has found some message that produces their desired tag and They can take advantage of that by for example Sending a message to be Zero one zero one one one One one with the tag zero one zero one if they send that to be B will verify it to be correct because B has the key that produces that mapping So that's how the attacker can take advantage of this the point is How many attempts do we need to make until we get the matching tag in this case? because it's random messages that took I don't know you can count them there better than me, but Maybe 20 something met attempts there. I'll try it again because it's random We're different this time a little bit longer. I'll keep trying. Oh that one took five attempts Maybe a screen full which is about 15 to 20 attempts and keep trying. Oh, this one's maybe 10 attempts If we keep trying because it's random what will vary on average How many attempts do we need to take until we get the right tag? Average or worst case worst case to be simple. What's the worst case? No Or the average of these values that we just did What do you think it is So we had one which is five one with 12 one looked like 20 25 if we kept doing and took the average What do you think will take? What does it depend upon? It doesn't depend upon the key length. It depends upon the tag length How many possible tags are there? 16 possible tags. So basically the MAC function takes some random input and produces one of those 16 values so after 16 attempts We should Possibly get one of the the value that we're looking for because ours is one of the 16 values But unfortunately in some cases an attempt produces the the same tag But on average if if it's a random mapping and we're looking for a random tag It would take 16 attempts to find our tag. It depends upon the tag length Basically the idea is Apply some function on a random input that produces one of those random 16 outputs On average you need 16 attempts to get that output So the attacker in this case will be successful the success depends upon the length of the tag How do we make it harder for the attacker then? longer tag Okay, so the longer the tag the less chance that they'll find it So there are two different approaches from the attacker and we'll go back to the lecture notes Actually, just to summarize here in the first case. We said if we try all keys it depends upon the key length three bits Take eight attempts if we try to find a tag by trying random messages. It depends upon the tag length four bits in this case so In general a brute force attack on the key takes approximately two to the power of K attempts a brute force attack on the tag on the Mac value Depends upon the length of that tag For an n-bit Mac value an n-bit tag takes two to the power of n attempts So from an attacker's perspective, they would choose the easiest of the two To defeat the Mac scheme choose the one which is easier So the the effort to defeat the Mac in a brute force attack is the minimum of two to the power of the number of bits in the key and two to the power of the number of bits in the tag if We had a Mac scheme a Mac function that had a key of 80 bits and a tag of 60 bits What would you as the attacker try to do a? brute force attack on the key or a brute force attack on the tag on The tag the one which is easier Okay, so that's why we say that the strength of the Mac depends upon the minimum length of the key and the tag So basically we need to make sure the tag and the key are both long enough to make a brute force attack Not possible. So as long as they take the key and the tag along Macs are considered secure against brute force Can we try it for 60 bits? You'll try it at home and leave your computer running and see see how much power you use over a week With 60 bits you can do it, but I think it will still take a long time on a single computer. So a A brute force attack I think we said on desk which was 64 bits or actually 56 bits Is possible today and I the numbers that it takes On powerful computers or a group of computers probably minutes to defeat but on a single computer that that extends Maybe if you took control of the network lab, you'll get it quite quickly use all 36 computers Right brute force is not practical if we make the values long enough and that's easy Okay, so most Mac algorithms used or all Mac algorithms are used we we use values which are long enough But the main point is that we need both the key and the tag to be long enough It's not just the key anymore So that's brute force attacks the other attacks to take advantage of weaknesses in the algorithms There are many different algorithms. So there are some theoretical attacks on some of the popular algorithms But generally Mac algorithms the ones which are in use today are considered secure So just make sure that the lengths are large enough and the max are considered secure We mentioned in the previous lecture that there are many different algorithms. We're not going to go through any specific one The next topic is about hash functions, which we'll go through and then we'll mention that there's a hash functions and Mac functions are used for similar things and the There is a Mac function called H Mac Which really takes an existing hash function and turns it into a Mac function So that's commonly used in network communications if you saw in Secure shell and we capture packets you'll see that H Mac is used in that case


Welcome to all of you wonderful people who have come out tonight to remember a great man, Martin Luther King, Jr. This part of the service will be very brief. We want to begin with just a moment of silence because anything and everything that we sing and say up here will hardly do justice to the memory of Martin King. Let us be in silence and then Juliet Young will sing for us. It's absolutely important for this event to be held in any public building in the city of Berlin or any place else. I am especially delighted that it's held here in City Hall. Because it's absolutely imperative, especially in these times, that City Halls hold up the United States of America of whole moral values and it's important that we honor Dr. King in this City Hall this time. Today, many of us in Burlington and people throughout the world are outraged and shot by the neo-nazi type activity which is taking place in South Africa. We find it incomprehensible that at the end of the 20th century, human beings who constitute the vast majority of that country's population can be treated in such a blatantly racist, violent and undemocratic manner. It is a tragedy for the people of South Africa. But how quickly we forget that not so many years ago, in the United States of America, black people in our own country, in the land of the free and in the home of the brave were not able to vote and had no voting rights. We denied the right to go to decent schools, went to segregated schools. We denied the right to decent job opportunities, were condemned to be your labor, were lynched, were kept illiterate. And in 1941, when the United States government went to war for freedom and democracy against the horrors of Nazism, we went to war in segregated military power. Black and white soldiers were unable to even fight side by side in the home of the free and the land of the brave. There came a time in American history after the war when the hypocrisy of reclaiming to the world that we were a land of the free could no longer be defended when black people were unable to sit with white people at lunch and ends or go to the same bathrooms or ride in the front of the bus. And there came at that same time a man, a very brave man, a very courageous man, Martin Luther King, Jr., who stood up along with many other people in the civil rights movement and led the struggle for black dignity and led the struggle and raised the voice for white America for a system of values that we could be proud of. He pointed away, the fear that I have today, 18 years after Martin Luther King's tragic death, is not just that it was a tragedy that he was struck down in the midst of an act of life, but I fear an even greater tragedy. It is always a tragedy when somebody dies young, but there's something worse that could happen, and in a sense I fear it is happening, that somebody dies is bad, but that when a great person dies who had a vision, and when that vision dies, that is even worse. There's anything important about tonight and about the celebrations that are taking place all over America, it's not just the honor of a great man and a brave man, everybody can do that, but it's the pledge of solid oath that the dream and the vision that Martin Luther King had not died. Mary Benson, a Burlington area school teacher who is also a member of the group Kwanzaa, which works in the schools to teach about racism. Nari was featured in a story in the free press yesterday and will I believe be talking about her experiences as a child in the Selma area and on the Selma march. I was born in Belglade, Florida. My parents taught and lived on a migrant camp. When I was three years old, we moved to Tuskegee Institute, Alabama. My father was a Presbyterian minister, my mother was and still is a librarian at the university there.  I did not really know any white people personally. My school, teachers, principal, neighborhood, church, supermarket, brownie and Girl Scout troops were all black. Downtown Tuskegee was another story. It was all white. My parents used the bank, then the only bank, but every other white owned business was boycotted. There was a white neighborhood that we drove through only at Christmas time to look at the Christmas decorations. I was 11 years old before I knew that Tuskegee had white schools and only then because three high school students, black high school students tried and succeeded to integrate them. When that happened, the Ku Klux Klan rode through our neighborhood because two of the students lived there. I remember lying on the couch in the living room shivering because I thought they'd come to my house. Black ministers' homes were high on the Klan's hit list. I believe, however, the deacons, a black defense against the Klan group made up of church elders may have helped them to just keep on riding. We shopped in Montgomery, the closest city, a Jim Crow city, the state capitol. My parents would never let us patronize any places that had segregated windows to do business through or segregated bathrooms unless it was absolutely necessary and only then with complete disgust and disdain. My brother and I never got to go to the circus or the fairs or Miss Patty's Playhouse, which were advertised so attractingly on television because only white children were allowed. At that time, I felt so cheated. I grew up with George Wallace as governor. He is still governor and, for me, still an embarrassment. Governor Wallace was a member of the Klan and a solid supporter and perpetrator of the Klan's beliefs. Blacks were harassed and killed all the time. It was more than once that white men and cars shouted angry words through rocks or tried to run us off the road. We weren't supposed to have working vehicles or decent clothing. We were too uppity and needed to be shown our place. Through it all, my parents never badmouth whites too much. They explain that all white people aren't bad.  They don't know any better or they're just sick and you must hope and pray that they get well.  Now Martin Luther King had a big part in my upbringing. His name was household. His picture hung and still does above my father's desk. We watched everything we could about him. My father and sister went to church to hear him. He led people to stand up for themselves. We were always worried for him. My parents talked about him to us all the time. They worked very hard to instill a sense of pride in us. A strength of spirit that was as ancient as Africa, as honorable as Native America, and as deeply rooted as all my grandmothers. A pride that could never be broken. Watching Dr. King on TV, reading about yet another of his arrest, walking through the streets of Selma in Montgomery with him, hearing his voice boom over land where no black voices were heard, helped to instill this pride. He was not alone. He was and is a reminder of what we as a people have been, what we are, what we could and can be. In times like now, we are attacked, abused, or assaulted. When one out of every two black children born here will live in poverty without adequate clothing, shelter, food, education, and health care. When many of today's college students have never heard about civil rights, were never taught about racism, don't know what anti-Semitism means and think feminism is old hat. When white supremacist organizations are on the rise, when affirmative action is being dismantled, when black unemployment is higher than ever, when Native Americans are still being ripped off and squeezed so our government can get at that oil, mineral, and uranium deposits under the land. And it was so graciously granted to them because it was thought to be a wasteland. When women and children still represent the largest and most oppressed group worldwide. When blacks in South Africa are waging a long and now violent struggle to get back their land from people who never had any right or claim to it in the first place, we must reevaluate our priorities. In times like these, we must choose the path of justice, of freedom and human rights, of hope and faith, and most of all of peace and self-determination. I wonder why it took so long for this nation to set aside a time to celebrate these values and goals to strive for. Although I am glad the city has chosen to honor Martin's dream tonight, I wonder why the city has not made Martin Luther King Day a holiday. As I've heard, we simply cannot afford it. I ask, how can we not afford it? I ask this of the state also. We need to reevaluate our priorities. We as a city, as a people, need to make our holidays real and worthwhile. What could be better to celebrate and have time to meditate upon than the end of oppression for all oppressed peoples? We can afford to celebrate a president who was a slave owner, a sailor who was discovered stealing onto this land by a group of Native Americans thinking he'd found India, a traditional feast that came before the death sentence was carried out against an entire culture and peoples, and yet we cannot afford to celebrate a holiday for peace and justice. Again, I say we need to reevaluate our priorities, personally, as a community, as a nation. Otherwise, we choose to continue on the path of self-destruction and total annihilation. Thank you. As long as we don't accept differences, as long as we don't respect differences, as long as there's one person in the world being oppressed, none of us are really free. I wish that life was free, and people were not longing for their fundamental needs. I wish that life was free. I wish that life was free, and men lost their control of society. I wish that life was free. I wish that life was free, and nobody had to be hungry. I wish that life was free. I wish that life was free, and women were not taught to live dependently. I wish that life was free. I wish that life was free, and everyone could receive what they needed medically. I wish that life was free. I wish that life was free, and children were not abused sexually. I wish that life was free. I wish that life was free, and we had not lost our ability to function psychically. I wish that life was free. I wish that life was free, and people of color were not treated so shabbily. I wish that life was free. I wish that life was free, and being old was something we all strive to be. I wish that life was free. I wish that life was free, and lesbians gays did not have to live so secretly. I wish that life was free. I wish that life was free, and we questioned what we learned about other countries. I wish that life was free. I wish that life was free, and in love we were not so vulnerable emotionally. I wish that life was free. I wish that life was free, and we related to each other spiritually. I wish that life was free. I wish that life was free, and we respected all abilities. I wish that life was free. I wish that life was free, and there was not any importance to having money. I wish that life was free. I wish that life was free, and the earth was valued as a living entity. I wish that life was free. I wish that life was free, and I could forget all the ugliness I have seen. I wish that life was free. I wish that life was free, and I was free to be me. Thank you.


Hi, my name is Ethan and I'm from sunny central, Florida You're watching trucker Josh and diesel on the best channel on YouTube tj v. Enjoy Everybody ain't filming this on Friday. We're on our way home We're gonna put the truck in gear because that always helps us go forward our way down The beautiful I-94 and clear water Minnesota right now. We're headed towards Fargo, North Dakota where we're gonna meet up with interstate 29 and Head north 75 and then turn left and do 190 meters Thanks Karen.  I showed you yesterday all day to be a truck driver. Look at us Oh, this guy had to park way out here for night.  I don't know what that was.  I Bet that thing's a little yappy little thing, too We're just rolling into Moorhead, Minnesota, which is gonna turn to Fargo, North Dakota as soon as we cross the Red River That means home stretch I-29 so it turns out I'm actually gonna have a weekend at home sort of There's somebody on the shoulder here. Yes, man coming back in coming back in coming back in Didn't see him there Poser beading coming up behind me. Anyway, I slowed him down to the right speed It's gonna give her again anyways because who likes doing this speed limit That's no fun Yeah, I was gonna deliver this load first thing Monday morning in Fort McMurray, right? And it's Friday right now and Fort McMurray is a two-day drive from home So that means I would have to drive there Saturday Sunday to be there Sunday night deliver Monday morning It turns out they only want it there Monday I'm pardoned Tuesday morning which works out better for me actually because now I can go and reset my logbooks tomorrow at home And leave Sunday Sunday drive Sunday Monday be there Monday night and unload at 8 a.m. Tuesday morning Look at one more day at home this way and this way my logs are reset as well And I'm ready for a full week Full week of work and I'm gonna have to make it a full week because I took it a little too easy last month Could use a few more nickels So this month I'm trying to you know, save up a few nickels. Maybe maybe even get a couple of dimes in there You know what I mean It's weekend. I am planning on going golfing with my cousins that I reconnected with at the the geese press reunion Last weekend, so we're gonna go golfing next Sunday And my our roof at home is getting redone The following Monday, they're beginning on it on Monday, so I'm trying to get to the point where I can leave Sunday right and then be back for the following Sunday be gone a week Maybe I can get three loads in in the week. It's gonna be rushed I'm gonna try to deliver Tuesday morning pick up a reload Tuesday somewhere. Hopefully Deliver that somewhere by before the end of the week and get reloaded once more to get home Means I love delivered two loads and have one sitting under me for the weekend that makes sense Truckers understand. I'm trying to plan out my my next week so I can be home when I need to be I want to go golfing and I want to be there when they do the roof I want to see how they do it. I think it'll be interesting and I'm excited to see the finished product Thanks Karen, I knew I was in North Dakota, but thanks anyway Look at that. Welcome to North Dakota legendary It is legendary It's only legendary because it's right next to Manitoba, right? Am I right? Okay? I'm home. I'm showered We're home until the day after tomorrow so for a 36 hour Canadian reset Now it's time To get out there and enjoy what's left of our summer And it's almost fall time already Let's not talk about that. Let's not talk about that.  Oh, yes. Here we go. Here we go. Oh, yep As soon as that coffee is ready, it's gonna be perfect This is life Outside breakfast needs us a very special day Breakfast on the porch or it could just mean that I don't want to leave the porch. So you guys can eat out here. How about that? Frank's already had his there. I got my coffee right here Got a sneeze coming down the pipes one second. I better put this down Let's say I'm allergic to something there. I've been having allergic reactions today. I'll probably take an allergy anti-hystamine They were allergic to work so it should get better today Just been working too much lately Not enough porch sitting right? I'm allergic to working not enough porch sitting You people love to work. That's very true. Maybe I'm allergic to not working. Maybe that's why I'm having sneezes today Maybe what's my excuse then? I was using the right bonfire Okay, well coffee dogs are fed Frankie's trying to convince diesel to share his breakfast with them.  Everybody missed you weasel Everybody missed you not you Chevy. You were there the whole time Yeah But the fire you got going here. I'm my mother's daughter My name is George out of New Jersey you're watching trucker Josh vlogs make sure to leave a comment hit the like button and subscribe


State of Alt is equipped with a variety of security measures. How you defeat those measures is up to you.


Now you're ready to create the final draft of the paper. And what you might want to do before you submit is ask a peer to read your paper. Let them look the whole thing over and read it to see if it makes sense. Is it clear? Is it concise? Is it written for the appropriate target audience? And ask your peer for feedback. But you need to be prepared to receive that feedback. I remember an incident once where a colleague of mine asked me to read her paper. She had finished her first draft and she thought she was ready to submit. So I read it and I wrote her a note and I told her I thought that the opening of her paper was a little corny. I would suggest changing it. She was offended by my comments and told me she was offended. And I said, well, you asked for some feedback. I gave you my honest feedback. Why don't you ask them other people's opinion? In the end you as the author have to decide. But if you're going to ask for feedback, you have to not personalize it. It's not a personal criticism of you and you have to be ready to accept that feedback.


assumptions that we had in Bernoulli's theorem so the first and second assumption it is irrotational flow in fluid dynamics here okay so we have the concept of viscosity all right so we have l struggling with this come second one so this will be kg you can do by direct here I know what is l l is my d v is this and the substitute this on this equation