SC700 - Modern Information Protocols

Research Projects




You will be responsible for completing two research projects in SC700, a paper presentation an research on an open problem.  Each prescreened project has been assigned a difficulty rating:

1 point = straightforward       2 points = moderate    3 points = challenging


For presentations, the difficulty reflects the readability and background needed for the corresponding paper.  For open problems, the difficulty reflects how well the problem is known and how much related literature is available.


The project grade will also be curved according to difficulty, so that an average challenging project might be assigned the same grade as a good straightforward project.  Finally, the difficulty of both projects must add up to at least 4 points and you can team up in groups of two on challenging projects if you wish.  In all cases, projects will be assigned on a "first-come first-serve" basis, and no projects may be repeated by more than one group.


Paper presentation (30 points):


This involves reading and fully comprehending one paper from the recent research on a topic relevant to the course.  Note that proper comprehension typically entails perusing several other background references, trying several small examples, or looking on the web for resources.  You will present the paper during a scheduled fifty minute talk in class.


Your presentation will be graded by me and by your classmates, who will also ask you probing questions about the paper.  The primary criteria for grading will be clarity, completeness, and expertise.  Please hold to the following timeline for submitting your presentation:

[1 point]          September 17:             Paper selection and presentation date due

[5 points]        October 15:                One page abstract of paper is due in your own words

[8 points]        1 week before pres.:   Draft copy of slides due

[16 points]      Date of pres.:              Present your paper


The following papers have been pre-screened; you are welcome to find your own presentation material, though you will have to solicit my approval for relevance.  Most of these are avialable on the World Wide Web (do a "Google" search on the title or go to the author’s web site):


Data compression:

Difficulty 2:

Amiya Bhattacharya and Sajal K. Das. Leziupdate: An information-theoretic approach to track mobile users in PCS networks. In Mobile Computing and Networking, pages 1--12, 1999.


Difficulty 3:

Joscha Bach, Ian H, "Lexical Attraction for Text Compression.", Data Compression Conference, DCC 1999, 29 - 31 March, 1999, Snowbird, Utah, USA.


J.C. Kieffer and E-H. Yang, "Grammar based codes: A new class of universal lossless source codes," IEEE Trans. Inform. Theory, Vol IT-46, No. 3, pp. 737--754, May 2000. 


M. Ajtai, R. Burns, R. Fagin, D.D.E. Long and L. Stockmeyer, “Compactly Encoding Unstructured Inputs with Differential Compression”, Journal of the ACM, to appear.


Error correction:

Difficulty 1:


Difficulty 2:

R.J. McEliece, "On the BCJR trellis for linear block codes", IEEE Transactions on Information Theory, vol. 42, pp. 1072-1092, 1996.


J.J. Metzner, and E.J. Kapturowski, "A general decoding technique applicable to replicated file disagreement location and concatenated code decoding", IEEE Trans. Information Theory, Vol. 36, No. 4, July 1990.


Difficulty 3:


V.I. Levenshtein, "Efficient Reconstruction of Sequences", IEEE Transactions on Information Theory, vol. 47, no. 1, p. 2-23, January 2001.


J.W. Byers, M. Luby, M. Mitzenmacher, A. Rege, "A digital fountain approach to reliable distribution of bulk data",  Proceedings of ACM SIGCOMM '98, Vancouver, September 1998.


M.G. Karpovsky, K. Chakrabarty, L.B. Levitin, "A new class of codes for identification of vertices in graphs", IEEE Transactions on Information Theory, March 1998.


M. Sudan, “Decoding Reed Solomon codes beyond the error-correction diameter”, Proc. 35th Annual Allerton Conference on Communication, Control, and Computing, 1997.


Y. Ofek, “The conservative code for bit synchronization”, IEEE Transactions on Communications, vol. 38, no. 7, July 1990.



Difficulty 1:

J.J. Quisquater and L. Guillou.  "How to explain zero-knowledge protocols to your children", Lecture Notes in Computer Science, 435 (1990), 628-631.

Lidong Zhou and Zygmunt J. Haas, "Securing Ad Hoc Networks". IEEE Networks Special Issue on

   Network Security. November/December, 1999.

Difficulty 2:

A. Juels and M. Sudan, "A Fuzzy Vault Scheme". Proceedings of IEEE Internation Symposium on Information Theory, p.408, IEEE Press, Lausanne, Switzerland, 2002. (only includes abstract, full version on web).

Difficulty 3:
D. Wong and A. Chan, “Efficient and Mutually Authenticated Key Exchange for Low Power Computing Devices”, Proc. ASIACRYPT 2001.  LNCS 2248 (Dec. 9-13, 2001, Australia).


R. Gennaro, Y. Gertner and J. Katz, “Bounds on the Efficiency of Encryption and Digital Signatures”, DIMACS Technical Report: 2002-22.


L. Knudesn and B. Preneel, “Construction of secure and fast hash functions using nonbinary error-correcting codes”, IEEE Transactions on Information Theory, vol. 48, September 2002.


Information dispersion:

Difficulty 1:


R. H. Frenkiel, B.R. Badrinath, J. Borras and R. Yates. “The Infostations Challenge: Balancing Cost and Ubiquity in Delivering Wireless Data”. IEEE Personal Communications 7(2):66-71. April, 2000


Difficulty 2:


K.A.S. Abdel-Ghaffar and A.E. Abbadi, "An optimal strategy for comparing file copies", IEEE Trans. on Parallel and Distributed Systems, vol. 5, no. 1, pp. 87-93, January 1994.


J. Byers, J. Considine, M. Mitzenmacher, and S. Rost, “Informed Content Delivery Across Adaptive Overlay Networks”, Proceedings of ACM SIGCOMM '02, August 2002, pp. 47-60.


Difficulty 3:

L. Kleinrock, "Information Flow in Large Communication Nets", RLE Quarterly Progress Report, July 1961.


G. Cormode, M. Paterson, S.C. Sahinalp, U. Vishkin, "Communication complexity of document exchange", Proc. ACM-SIAM Symp. on Discrete Algorithms, 2000.


T. Schwarz, R.W. Bowdidge, W.A. Bukhard, "Low cost comparisons of file copies", Proc. IEEE Conference on Distributed Computing Systems, p. 196-202, 1990.


L. Fan, P.Cao, J. Almeida, and A.Z. Broder, "Summary cache:  a scalable wide-area web cache sharing protocol", IEEE/ACM Transactions on Networking, vol. 8, No. 3, June 2000.

A. C. Yao, “Some complexity questions related to distributive computing”, Proceedings of the 11th Annual ACM Symposium on Theory of Computing, 1979, pages 209—213.
Open problems (30 points):


This project involves trying to solve a problem whose solution has not yet been discovered.  Clearly, I do not expect you to actually solve these problems, but rather to take the first steps in addressing a real research problem and make a sincere effort to solve it.  Students who do completely and clearly solve one of these problems will, after I have certified that the solution is indeed novel and problem yet unsolved, get an automatic A for the course.  As with the paper presentation, you may find an open problem by yourself, if you wish, as long as I approve it.


Please hold to the following timeline for submitting your presentation:

[1 point]          September 19:             Problem selection due

-----------         week of Sept 24:         Individual meetings to discuss project

[3 points]        October 3:                  Five relevant references due

[10 points]      October 31:                Provide solution to the simple instance of problem

[10 points]      December 3:               Final report due

[6 points]        last 2 weeks of class:  Presentation of results (30 minutes)


Your final report must include a survey of existing literature relating to your problem and a review of three different approaches you attempted to solve the problem.


Data compression:
Difficulty 3:

Problem:  Compression with error-correcting codes.

Question:  Is it possible to improve data compression in general using an error correcting code?  Specifically, one can take a message m and encode it with an error correcting code C into an encoding c = Cm.  We may now introduce “errors” e into c, up to the error correcting capability of C, and the question is whether it is generally possible to design c and e in such a way that c+e can be Lempel-Ziv compressed to a shorter string than m.

Instance:  Give an example message of at least 20 bits demonstrating improved compression.


Problem:  Entropy of WWW.

Question:  Compute the entropy of text on the WWW, together with good error bars.

Instance:  Compute the entropy of all text on the official BU web site.

Error correction:

Difficulty 2:

Problem:  Minimum distance approximation.

Question:  Prove or disprove that no polynomial time algorithm can approximate the minimum distance of an arbitrary linear code within a multiplicative constant.

Instance:  Find the minimum distance of the linear code with the following generator matrix:























Problem:  Shannon limit.

Question:  Construct a family of error-correcting codes whose rate attains Shannon’s capacity with a bit error rate of 10-5 over an additive white noise Gaussian channel, and which can be coded and decoded in polynomial time and space.

Instance:  Construct an LDPC that approaches within 1dB of Shannon’s limit (under the same terms as above) and show this empirically.

Difficulty 3:

Problem:  Parameters of lexicodes.

Question:  Compute the length, dimension, and minimum distance of an arbitrary binary lexicographic code (lexicode).

Instance:  Compute the length of the binary lexicode with minimum distance 12 and dimension 4.





Difficulty 1:

Problem:  Integer factorization.

Question:  Provide (or prove non-existent) a polynomial time algorithm for determining some factor of an arbitrary integer n.

Instance:  Find the smallest integer between 107 and 108, inclusive, whose prime factors have the smallest sum.  If a factor appears more than once in the factorization, it should be added more than once to the sum.

Difficulty 2:

Problem:  Discrete logarithm.

Question:  Provide (or prove non-existent) a polynomial time algorithm for computing an exponent e such that be = m (mod p) for arbitrary integers b,m, and prime p.

Instance:  Solve for e:  5e = 948603 (mod 8187734305878054004900051).


Difficulty 3:

Problem:  Hash inversion.

Question:  Construct a family of hash functions that can be computed with a number of (AND, OR, and NOT) gates linear in the size of their inputs, but whose inverse cannot be computed in a polynomial number of gates.

Instance:  Provide a hash function that requires fewer gates to compute than its inverse.


Information dispersion:


Difficulty 3:

Problem:  Network synchronization.

Question:  Provide (or prove non-existent) a polynomial time algorithm for synchronizing an arbitrary network of n hosts, each with a set of b-bit integers.  Assume that the amount of communication needed to synchronize two hosts is proportional to the number of differences between the two hosts.

Instance:  Give an optimal synchronization for 10 hosts where the i-th host has a set of 2i integers disjoint from the other hosts.


Problem:  Comparison checking.

Question:  Provide an algorithm that uses (provedly) minimum communication to determine whether two physically separate sets are more than 90% the same or less than 10% the same (or neither).

Instance:  Provide an algorithm that uses a (provedly) minimum communication to determine whether two physically separate sets are exactly the same or not.