| 132 |      1 | <?xml version="1.0" encoding="utf-8"?>
 | 
|  |      2 | <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
 | 
|  |      3 | <HEAD>
 | 
|  |      4 | <TITLE>2012/13 BSc Projects</TITLE>
 | 
| 465 |      5 | <BASE HREF="http://nms.kcl.ac.uk/christian.urban/">
 | 
| 132 |      6 | <script type="text/javascript" src="striper.js"></script>
 | 
|  |      7 | <link rel="stylesheet" href="nominal.css">
 | 
|  |      8 | </HEAD>
 | 
|  |      9 | <BODY TEXT="#000000" 
 | 
|  |     10 |       BGCOLOR="#4169E1" 
 | 
|  |     11 |       LINK="#0000EF" 
 | 
|  |     12 |       VLINK="#51188E" 
 | 
|  |     13 |       ALINK="#FF0000"
 | 
|  |     14 |       ONLOAD="striper('ul','striped','li','first,second')">
 | 
|  |     15 | 
 | 
|  |     16 | 
 | 
|  |     17 | 
 | 
|  |     18 | <TABLE WIDTH="100%" 
 | 
|  |     19 |        BGCOLOR="#4169E1" 
 | 
|  |     20 |        BORDER="0"   
 | 
|  |     21 |        FRAME="border"  
 | 
|  |     22 |        CELLPADDING="10"     
 | 
|  |     23 |        CELLSPACING="2"
 | 
|  |     24 |        RULES="all">
 | 
|  |     25 | 
 | 
|  |     26 | <TR>
 | 
|  |     27 | <TD BGCOLOR="#FFFFFF" 
 | 
|  |     28 |     WIDTH="75%" 
 | 
|  |     29 |     VALIGN="TOP">
 | 
|  |     30 | 
 | 
|  |     31 | <H2>2012/13 BSc Projects</H2>
 | 
|  |     32 | <H4>Supervisor: Christian Urban</H4> 
 | 
| 151 |     33 | <H4>Email: christian dot urban at kcl dot ac dot uk,  Office: Strand Building S1.27</H4>
 | 
| 132 |     34 | <H4>If you are interested in a project, please send me an email and we can discuss details. Please include
 | 
|  |     35 | a short description about your programming skills and Computer Science background in your first email. 
 | 
|  |     36 | I will also need your King's username in order to book the project for you. Thanks.</H4> 
 | 
|  |     37 | 
 | 
| 143 |     38 | <H4>Note that besides being a lecturer at the theoretical end of Computer Science, I am also a passionate
 | 
| 132 |     39 |     <A HREF="http://en.wikipedia.org/wiki/Hacker_(programmer_subculture)">hacker</A> …
 | 
|  |     40 |     defined as “a person who enjoys exploring the details of programmable systems and 
 | 
|  |     41 |     stretching their capabilities, as opposed to most users, who prefer to learn only the minimum 
 | 
|  |     42 |     necessary.” I am always happy to supervise like-minded students.</H4>  
 | 
|  |     43 | 
 | 
|  |     44 | <ul class="striped">
 | 
|  |     45 | <li> <H4>[CU1] Automata Minimisation</H4>
 | 
|  |     46 | 
 | 
| 143 |     47 |   <p>
 | 
|  |     48 |   <B>Description:</b>  
 | 
| 132 |     49 |   <A HREF="http://en.wikipedia.org/wiki/Deterministic_finite_automaton">Deterministic finite automata</A> 
 | 
|  |     50 |   have many uses in Computer Science, for example for lexing
 | 
|  |     51 |   program code. In order to improve their run-time, automata need to be minimised, that 
 | 
|  |     52 |   is transformed into equivalent automata with the smallest possible number of state 
 | 
|  |     53 |   nodes. 
 | 
|  |     54 |   </p>
 | 
|  |     55 | 
 | 
|  |     56 |   <p>
 | 
|  |     57 |   There is a little known method for minimising deterministic finite
 | 
|  |     58 |   automata by <A HREF="http://en.wikipedia.org/wiki/Janusz_Brzozowski_(computer_scientist)">
 | 
|  |     59 |   Janusz Brzozowski</A>. 
 | 
|  |     60 |   This method first reverses the edges of an automaton, which produces
 | 
|  |     61 |   a potentially non-deterministic automaton. The non-deterministic automaton is 
 | 
|  |     62 |   then determinised using the usual powerset construction. This is repeated
 | 
|  |     63 |   once more and voila you obtain a minimised version of the automaton
 | 
|  |     64 |   you started with. It is rather surprising that this method works at all: 
 | 
|  |     65 |   the powerset construction might produce an automaton with an exponentially 
 | 
|  |     66 |   larger number of states, completely contrary to the idea of minimising the
 | 
|  |     67 |   number of states. The task of this project is to implement this method, check that
 | 
|  |     68 |   it actually works with some examples and
 | 
|  |     69 |   compare it with more traditional methods for automata minimisation
 | 
|  |     70 |   (in terms of run-time, code complexity, etc). Examples can be 
 | 
| 133 |     71 |   obtained by translating regular expressions into automata. A natural extension
 | 
|  |     72 |   of the project is therefore to implement a recogniser for regular expressions
 | 
|  |     73 |   following, for example, this <A HREF="http://www.cl.cam.ac.uk/~so294/documents/jfp09.pdf">paper</A>. 
 | 
| 132 |     74 |   </p>
 | 
|  |     75 | 
 | 
|  |     76 |   <p>
 | 
|  |     77 |   <B>Literature:</B> 
 | 
|  |     78 |   A good place to start with this project are the wikipedia articles 
 | 
|  |     79 |   <A HREF="http://en.wikipedia.org/wiki/DFA_minimization">here</A> and 
 | 
|  |     80 |   <A HREF="http://en.wikipedia.org/wiki/Powerset_construction">here</A>.
 | 
|  |     81 |   The authoritative <A HREF="http://infolab.stanford.edu/~ullman/ialc.html">book</A>
 | 
|  |     82 |   on automata is by John Hopcroft and Jeffrey Ullmann (available in the library). 
 | 
|  |     83 |   There is also an online course about automata by Ullman at 
 | 
|  |     84 |   <A HREF="https://www.coursera.org/course/automata">Coursera</A>, though IMHO not 
 | 
|  |     85 |   done with love. There
 | 
|  |     86 |   is also the book <i>Automata and Computability</i> by 
 | 
|  |     87 |   <A HREF="http://www.cs.cornell.edu/~kozen/">Dexter Kozen</A> including more 
 | 
|  |     88 |   advanced material about automata.
 | 
|  |     89 |   Finally, there are millions of other pointers about automata
 | 
| 145 |     90 |   minimisation on the web. Finally, I will give a lot of the background in
 | 
|  |     91 |   my Automata and Formal Languages course (6CCS3AFL), which starts in September.
 | 
| 132 |     92 |   </p>
 | 
|  |     93 | 
 | 
|  |     94 |   <p>
 | 
|  |     95 |   <B>Skills:</B> 
 | 
|  |     96 |   This is a project for a student with an interest in theory and some
 | 
|  |     97 |   reasonable programming skills. The project can be easily implemented
 | 
|  |     98 |   in languages like
 | 
|  |     99 |   <A HREF="http://www.scala-lang.org/">Scala</A>,
 | 
|  |    100 |   <A HREF="http://en.wikipedia.org/wiki/Standard_ML">ML</A>,  
 | 
|  |    101 |   <A HREF="http://haskell.org/haskellwiki/Haskell">Haskell</A>, 
 | 
|  |    102 |   <A HREF="http://www.python.org">Python</A>, etc.
 | 
|  |    103 |   </p>
 | 
|  |    104 | 
 | 
|  |    105 | <li> <H4>[CU2] Equivalence Checking of Regular Expressions</H4>
 | 
|  |    106 | 
 | 
| 143 |    107 |   <p>
 | 
|  |    108 |   <B>Description:</b>  
 | 
| 132 |    109 |   Solving the problem of deciding the equivalence of regular expressions can be used
 | 
|  |    110 |   to decide a number of problems in automated reasoning. Recently, 
 | 
|  |    111 |   <A HREF="http://www.cs.unibo.it/~asperti/">Andreas Asperti</A>
 | 
|  |    112 |   proposed a simple method for deciding regular expression equivalence described
 | 
|  |    113 |   <A HREF="http://www.cs.unibo.it/~asperti/PAPERS/compact.pdf">here</A>. 
 | 
|  |    114 |   The task is to implement this method and test it on examples.
 | 
| 133 |    115 |   It would be also interesting to see whether Asperti's method applies to
 | 
| 132 |    116 |   extended regular expressions, described
 | 
|  |    117 |   <A HREF="http://ww2.cs.mu.oz.au/~sulzmann/manuscript/reg-exp-partial-derivatives.pdf">here</A>.
 | 
|  |    118 |   </p>
 | 
|  |    119 | 
 | 
|  |    120 |   <p>
 | 
|  |    121 |   <B>Literature:</B> 
 | 
|  |    122 |   The central literature is obviously the papers
 | 
|  |    123 |   <A HREF="http://www.cs.unibo.it/~asperti/PAPERS/compact.pdf">here</A> and
 | 
|  |    124 |   <A HREF="http://ww2.cs.mu.oz.au/~sulzmann/manuscript/reg-exp-partial-derivatives.pdf">here</A>.
 | 
|  |    125 |   Asperti has also some slides <A HREF="http://www.cs.unibo.it/~asperti/SLIDES/regular.pdf">here</a>.
 | 
|  |    126 |   More references about regular expressions can be found
 | 
| 145 |    127 |   <A HREF="http://en.wikipedia.org/wiki/Regular_expression">here</A>. Like in
 | 
|  |    128 |   [CU1], I will give a lot of the background pf this project in
 | 
|  |    129 |   my Automata and Formal Languages course (6CCS3AFL).
 | 
| 132 |    130 |   </p>  
 | 
|  |    131 | 
 | 
|  |    132 |   <p>
 | 
|  |    133 |   <B>Skills:</B> 
 | 
|  |    134 |   This is a project for a student with a passion for theory and some
 | 
|  |    135 |   reasonable programming skills. The project can be easily implemented
 | 
|  |    136 |   in languages like Scala
 | 
|  |    137 |   <A HREF="http://www.scala-lang.org/">Scala</A>,
 | 
|  |    138 |   <A HREF="http://en.wikipedia.org/wiki/Standard_ML">ML</A>,  
 | 
|  |    139 |   <A HREF="http://haskell.org/haskellwiki/Haskell">Haskell</A>, 
 | 
|  |    140 |   <A HREF="http://www.python.org">Python</A>, etc.
 | 
|  |    141 |   Being able to read <A HREF="http://haskell.org/haskellwiki/Haskell">Haskell</A>
 | 
|  |    142 |   code is beneficial for the part involving extended regular expressions.
 | 
|  |    143 |   </p>
 | 
|  |    144 | 
 | 
|  |    145 | <li> <H4>[CU3] Machine Code Generation for a Simple Compiler</H4>
 | 
|  |    146 | 
 | 
| 143 |    147 |   <p>
 | 
|  |    148 |   <b>Description:</b> 
 | 
| 132 |    149 |   Compilers translate high-level programs that humans can read and write into
 | 
|  |    150 |   efficient machine code that can be run on a CPU or virtual machine.
 | 
|  |    151 |   I recently implemented a very simple compiler for a very simple functional
 | 
|  |    152 |   programming language following this 
 | 
|  |    153 |   <A HREF="http://www.cs.princeton.edu/~dpw/papers/tal-toplas.pdf">paper</A> 
 | 
|  |    154 |   (also described <A HREF="http://www.cs.princeton.edu/~dpw/papers/tal-tr.pdf">here</A>).
 | 
|  |    155 |   My code, written in <A HREF="http://www.scala-lang.org/">Scala</A>, of this compiler is 
 | 
|  |    156 |   <A HREF="http://www.dcs.kcl.ac.uk/staff/urbanc/compiler.scala">here</A>.
 | 
|  |    157 |   The compiler can deal with simple programs involving natural numbers, such
 | 
|  |    158 |   as Fibonacci numbers
 | 
|  |    159 |   or factorial (but it can be easily extended - that is not the point).
 | 
|  |    160 |   </p>
 | 
|  |    161 | 
 | 
|  |    162 |   <p>
 | 
|  |    163 |   While the hard work has been done (understanding the two papers above),
 | 
|  |    164 |   my compiler only produces some idealised machine code. For example I
 | 
|  |    165 |   assume there are infinitely many registers. The goal of this
 | 
| 133 |    166 |   project is to generate machine code that is more realistic and can
 | 
|  |    167 |   run on a CPU, like x86, or run on a virtual machine, say the JVM. 
 | 
| 132 |    168 |   This gives probably a speedup of thousand times in comparison to
 | 
|  |    169 |   my naive machine code and virtual machine. The project
 | 
|  |    170 |   requires to dig into the literature about real CPUs and generating 
 | 
|  |    171 |   real machine code. 
 | 
|  |    172 |   </p>
 | 
|  |    173 | 
 | 
|  |    174 |   <p>
 | 
|  |    175 |   <B>Literature:</B>
 | 
|  |    176 |   There is a lot of literature about compilers 
 | 
|  |    177 |   (for example <A HREF="http://www.cs.princeton.edu/~appel/papers/cwc.html">this book</A> -
 | 
|  |    178 |   I can lend you my copy for the duration of the project). A very good overview article
 | 
|  |    179 |   about implementing compilers by 
 | 
|  |    180 |   <A HREF="http://tratt.net/laurie/">Laurie Tratt</A> is 
 | 
|  |    181 |   <A HREF="http://tratt.net/laurie/tech_articles/articles/how_difficult_is_it_to_write_a_compiler">here</A>.
 | 
|  |    182 |   An introduction into x86 machine code is <A HREF="http://ianseyler.github.com/easy_x86-64/">here</A>.
 | 
| 134 |    183 |   Intel's official manual for the x86 instruction is 
 | 
| 144 |    184 |   <A HREF="http://download.intel.com/design/intarch/manuals/24319101.pdf">here</A>. 
 | 
| 132 |    185 |   A simple assembler for the JVM is described <A HREF="http://jasmin.sourceforge.net">here</A>.
 | 
|  |    186 |   An interesting twist of this project is to not generate code for a CPU, but
 | 
|  |    187 |   for the intermediate language of the <A HREF="http://llvm.org">LLVM</A> compiler
 | 
|  |    188 |   (also described <A HREF="https://wiki.aalto.fi/display/t1065450/LLVM+IR">here</A> and
 | 
| 143 |    189 |   <A HREF="http://llvm.org/docs/LangRef.html">here</A>). If you want to see
 | 
|  |    190 |   what machine code looks like you can compile your C-program using gcc -S.
 | 
| 132 |    191 |   </p>
 | 
|  |    192 | 
 | 
| 143 |    193 |   <p>
 | 
|  |    194 |   <B>Skills:</B> 
 | 
| 132 |    195 |   This is a project for a student with a deep interest in programming languages and
 | 
|  |    196 |   compilers. Since my compiler is implemented in <A HREF="http://www.scala-lang.org/">Scala</A>,
 | 
|  |    197 |   it would make sense to continue this project in this language. I can be
 | 
|  |    198 |   of help with questions and books about <A HREF="http://www.scala-lang.org/">Scala</A>.
 | 
|  |    199 |   But if Scala is a problem, my code can also be translated quickly into any other functional
 | 
|  |    200 |   language. 
 | 
|  |    201 |   </p>
 | 
|  |    202 | 
 | 
|  |    203 | <li> <H4>[CU4] Implementation of Register Spilling Algorithms</H4>
 | 
|  |    204 |   
 | 
| 143 |    205 |   <p>
 | 
|  |    206 |   <b>Description:</b> 
 | 
| 132 |    207 |   This project is similar to [CU3]. The emphasis here, however, is on the
 | 
|  |    208 |   implementation and comparison of register spilling algorithms, also often called register allocation 
 | 
|  |    209 |   algorithms. They are part of any respectable compiler.  As said
 | 
|  |    210 |   in [CU3], however, my simple compiler lacks them and assumes an infinite amount of registers instead.
 | 
|  |    211 |   Real CPUs however only provide a fixed amount of registers (for example
 | 
|  |    212 |   x86-64 has 16 general purpose registers). Whenever a program needs
 | 
|  |    213 |   to hold more values than registers, the values need to be “spilled”
 | 
|  |    214 |   into the main memory. Register spilling algorithms try to minimise
 | 
|  |    215 |   this spilling, since fetching values from main memory is a costly 
 | 
|  |    216 |   operation. 
 | 
|  |    217 |   </p>
 | 
|  |    218 | 
 | 
|  |    219 |   <p>
 | 
|  |    220 |   The classic algorithm for register spilling uses a
 | 
|  |    221 |   <A HREF="http://en.wikipedia.org/wiki/Register_allocation">graph-colouring method</A>.
 | 
|  |    222 |   However, for some time the <A HREF="http://llvm.org">LLVM</A> compiler
 | 
|  |    223 |   used a supposedly more efficient method, called the linear scan allocation method
 | 
|  |    224 |   (described 
 | 
|  |    225 |   <A HREF="http://www.cs.ucla.edu/~palsberg/course/cs132/linearscan.pdf">here</A>).
 | 
|  |    226 |   However, it was later decided to abandon this method in favour of 
 | 
|  |    227 |   a <A HREF="http://blog.llvm.org/2011/09/greedy-register-allocation-in-llvm-30.html">
 | 
|  |    228 |   greedy register allocation</A> method. It would be nice if this project can find out
 | 
|  |    229 |   what the issues are with these methods and implement at least one of them for the 
 | 
|  |    230 |   simple compiler referenced in [CU3].
 | 
|  |    231 |   </p>
 | 
|  |    232 | 
 | 
|  |    233 |   <p>
 | 
|  |    234 |   <B>Literature:</B> 
 | 
|  |    235 |   The graph colouring method is described in Andrew Appel's 
 | 
|  |    236 |   <A HREF="http://www.cs.princeton.edu/~appel/modern/java/">book</A> on compilers
 | 
|  |    237 |   (I can give you my copy of this book, if it is not available in the library).
 | 
|  |    238 |   There is also a survey 
 | 
|  |    239 |   <A HREF="http://compilers.cs.ucla.edu/fernando/publications/drafts/survey.pdf">article</A> 
 | 
|  |    240 |   about register allocation algorithms with further pointers.
 | 
|  |    241 |   </p>
 | 
|  |    242 | 
 | 
| 143 |    243 |   <p>
 | 
|  |    244 |   <B>Skills:</B> 
 | 
| 132 |    245 |   Same skills as [CU3].
 | 
|  |    246 |   </p>
 | 
|  |    247 | 
 | 
|  |    248 | <li> <H4>[CU5] A Student Polling System</H4>
 | 
| 143 |    249 | 
 | 
| 132 |    250 |   <p>
 | 
|  |    251 |   <B>Description:</B>
 | 
|  |    252 |   One of the more annoying aspects of giving a lecture is to ask a question
 | 
|  |    253 |   to the students and no matter how easy the questions is to not 
 | 
|  |    254 |   receive an answer. Recently, the online course system 
 | 
|  |    255 |   <A HREF="http://www.udacity.com">Udacity</A> made an art out of
 | 
|  |    256 |   asking questions during lectures (see for example the
 | 
|  |    257 |   <A HREF="http://www.udacity.com/overview/Course/cs253/CourseRev/apr2012">Web Application Engineering</A> 
 | 
|  |    258 |   course CS253).
 | 
|  |    259 |   The lecturer there gives multiple-choice questions as part of the lecture and the students need to 
 | 
|  |    260 |   click on the appropriate answer. This works very well in the online world. 
 | 
|  |    261 |   For  “real-world” lectures, the department has some 
 | 
|  |    262 |   <A HREF="http://en.wikipedia.org/wiki/Audience_response">clickers</A>
 | 
|  |    263 |   (these are little devices part of an audience response systems). However, 
 | 
|  |    264 |   they are a logistic nightmare for the lecturer: they need to be distributed 
 | 
|  |    265 |   during the lecture and collected at the end. Nowadays, where students
 | 
|  |    266 |   come with their own laptop or smartphone to lectures, this can
 | 
|  |    267 |   be improved.
 | 
|  |    268 |   </p>
 | 
|  |    269 | 
 | 
|  |    270 |   <p>
 | 
|  |    271 |   The task of this project is to implement an online student
 | 
|  |    272 |   polling system. The lecturer should be able to prepare 
 | 
|  |    273 |   questions beforehand (encoded as some web-form) and be able to 
 | 
|  |    274 |   show them during the lecture. The students
 | 
|  |    275 |   can give their answers by clicking on the corresponding webpage.
 | 
|  |    276 |   The lecturer can then collect the responses online and evaluate them 
 | 
|  |    277 |   immediately. Such a system is sometimes called
 | 
|  |    278 |   <A HREF="http://en.wikipedia.org/wiki/Audience_response#Smartphone_.2F_HTTP_voting">HTML voting</A>. 
 | 
|  |    279 |   There are a number of commercial
 | 
|  |    280 |   solutions for this problem, but they are not easy to use (in addition
 | 
|  |    281 |   to being ridiculously expensive). A good student can easily improve upon
 | 
|  |    282 |   what they provide. 
 | 
|  |    283 |   </p>
 | 
|  |    284 | 
 | 
|  |    285 |   <p>
 | 
|  |    286 |   The problem of student polling is not as hard as 
 | 
|  |    287 |   <A HREF="http://en.wikipedia.org/wiki/Electronic_voting">electronic voting</A>, 
 | 
|  |    288 |   which essentially is still an unsolved problem in Computer Science. The
 | 
|  |    289 |   students only need to be prevented from answering question more than once thus skewing
 | 
|  |    290 |   any statistics. Unlike electronic voting, no audit trail needs to be kept
 | 
| 133 |    291 |   for student polling. Restricting the number of answers can probably be solved 
 | 
| 132 |    292 |   by setting appropriate cookies on the students
 | 
|  |    293 |   computers or smart phones.
 | 
|  |    294 |   </p>
 | 
|  |    295 | 
 | 
|  |    296 |   <p>
 | 
|  |    297 |   <B>Literature:</B> 
 | 
|  |    298 |   The project requires fluency in a web-programming language (for example 
 | 
|  |    299 |   <A HREF="http://en.wikipedia.org/wiki/JavaScript">Javascript</A>,
 | 
|  |    300 |   <A HREF="http://en.wikipedia.org/wiki/PHP">PHP</A>, 
 | 
| 143 |    301 |   Java, <A HREF="http://www.python.org">Python</A>, 
 | 
|  |    302 |   <A HREF="http://en.wikipedia.org/wiki/Go_(programming_language)">Go</A>, 
 | 
|  |    303 |   <A HREF="http://www.scala-lang.org/">Scala</A>,
 | 
| 132 |    304 |   <A HREF="http://en.wikipedia.org/wiki/Ruby_(programming_language)">Ruby</A>) 
 | 
|  |    305 |   and possibly a cloud application platform (for example
 | 
|  |    306 |   <A HREF="https://developers.google.com/appengine/">Google App Engine</a> or 
 | 
|  |    307 |   <A HREF="http://www.heroku.com">Heroku</A>).
 | 
|  |    308 |   For web-programming the 
 | 
|  |    309 |   <A HREF="http://www.udacity.com/overview/Course/cs253/CourseRev/apr2012">Web Application Engineering</A>
 | 
|  |    310 |   course at <A HREF="http://www.udacity.com">Udacity</A> is a good starting point 
 | 
|  |    311 |   to be aware of the issues involved. This course uses <A HREF="http://www.python.org">Python</A>.
 | 
| 133 |    312 |   To evaluate the answers from the student, Google's 
 | 
|  |    313 |   <A HREF="https://developers.google.com/chart/image/docs/making_charts">Chart Tools</A>
 | 
|  |    314 |   might be useful, which ar also described in this 
 | 
|  |    315 |   <A HREF="http://www.youtube.com/watch?v=NZtgT4jgnE8">youtube</A> video.
 | 
| 132 |    316 |   </p>
 | 
|  |    317 | 
 | 
| 143 |    318 |   <p>
 | 
|  |    319 |   <B>Skills:</B> 
 | 
| 132 |    320 |   In order to provide convenience for the lecturer, this project needs very good web-programming skills. A 
 | 
|  |    321 |   <A HREF="http://en.wikipedia.org/wiki/Hacker_(programmer_subculture)">hacker mentality</A>
 | 
|  |    322 |   (see above) is probably very beneficial: web-programming is an area that only emerged recently and
 | 
|  |    323 |   many tools still lack maturity. You probably have to experiment a lot with several different
 | 
|  |    324 |   languages and tools.
 | 
|  |    325 |   </p>
 | 
|  |    326 | 
 | 
| 140 |    327 | <li> <H4>[CU6] Implementation of a Distributed Clock-Synchronisation Algorithm developed at NASA</H4>
 | 
| 143 |    328 |   
 | 
| 140 |    329 |   <p>
 | 
|  |    330 |   <B>Description:</B>
 | 
| 141 |    331 |   There are many algorithms for synchronising clocks. This
 | 
| 140 |    332 |   <A HREF="http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20120000054_2011025573.pdf">paper</A> 
 | 
| 141 |    333 |   describes a new algorithm for clocks that communicate by exchanging
 | 
|  |    334 |   messages and thereby reach a state in which (within some bound) all clocks are synchronised.
 | 
| 143 |    335 |   A slightly longer and more detailed paper about the algorithm is 
 | 
|  |    336 |   <A HREF="http://hdl.handle.net/2060/20110020812">here</A>.
 | 
| 141 |    337 |   The point of this project is to implement this algorithm and simulate networks of clocks.
 | 
| 140 |    338 |   </p>
 | 
|  |    339 | 
 | 
| 144 |    340 |   <p>
 | 
| 140 |    341 |   <B>Literature:</B> 
 | 
| 141 |    342 |   There is a wide range of literature on clock syncronisation algorithms. 
 | 
|  |    343 |   Some pointers are given in this
 | 
|  |    344 |   <A HREF="http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20120000054_2011025573.pdf">paper</A>,
 | 
|  |    345 |   which describes the algorithm to be implemented in this project. Pointers
 | 
|  |    346 |   are given also <A HREF="http://en.wikipedia.org/wiki/Clock_synchronization">here</A>.
 | 
| 140 |    347 |   </p>
 | 
|  |    348 | 
 | 
| 143 |    349 |   <p>
 | 
|  |    350 |   <B>Skills:</B> 
 | 
| 141 |    351 |   In order to implement a simulation of a network of clocks, you need to tackle
 | 
| 140 |    352 |   concurrency. You can do this for example in the programming language
 | 
| 141 |    353 |   <A HREF="http://www.scala-lang.org/">Scala</A> with the help of the 
 | 
|  |    354 |   <A HREF="http://akka.io">Akka</a> library. This library enables you to send messages
 | 
|  |    355 |   between different <I>actors</I>. <A HREF="http://www.scala-lang.org/node/242">Here</A> 
 | 
|  |    356 |   are some examples that explain how to implement exchanging messages between actors. 
 | 
| 140 |    357 |   </p>
 | 
|  |    358 | 
 | 
| 132 |    359 | </ul>
 | 
|  |    360 | </TD>
 | 
|  |    361 | </TR>
 | 
|  |    362 | </TABLE>
 | 
|  |    363 | 
 | 
| 143 |    364 | <P>
 | 
|  |    365 | <!-- Created: Tue Mar  4 00:23:25 GMT 1997 -->
 | 
| 132 |    366 | <!-- hhmts start -->
 | 
| 143 |    367 | Last modified: Wed Sep 12 16:30:03 GMT 2012
 | 
| 132 |    368 | <!-- hhmts end -->
 | 
|  |    369 | <a href="http://validator.w3.org/check/referer">[Validate this page.]</a>
 | 
|  |    370 | </BODY>
 | 
|  |    371 | </HTML>
 |