An algorithm for anonymous sharing of private data amongNparties is developed. This technique is used iteratively to assign these nodes ID numbers ranging from 1 toN. This assignment is anonymous in that the identities received are unknown to the other members of the group. Resistance to collusion among other members is verified in an information theoretic sense when private communication channels are used. This assignment of serial numbers allows more complex data to be shared and has applications to other problems in privacy preserving data mining, collision avoidance in communications and distributed database access. The required computations are distributed without using a trusted central authority. Existing and new algorithms for assigning anonymous IDs are examined with respect to trade-offs between communication and computational requirements. The new algorithms are built on top of a secure sum data mining operation using Newton's identities and Sturm's theorem. An algorithm for distributed solution of certain polynomials over finite fields enhances the scalability of the algorithms. Markov chain representations are used to find statistics on the number of iterations required, and computer algebra gives closed form results for the completion rates.

In this article we investigate a new algorithm for solving the optimal task assignment problem. The assignment is based on Stone's "throughput" metric with the optimality criteria being the total cost for execution and interprocess communication. Two approaches studied are a new approach based on genetic algorithms and A*, a well known tree search algorithm for solving the same problem. We use the algorithm execution time as a performance criteria for the two algorithms. It is shown that the genetic algorithm techniques are more favorable than A* for larger search spaces while for smaller search spaces A* is preferred.

C. C. Shen and W. H. Tsai (IEEE Trans. Comput., vol.C-34, no.3, p.197-203 1985) proposed a graph matching algorithm for solving the static task assignment problem. It combines two important ideas: (1) graph homomorphism and (2) application of the A* algorithm. Task-dependent information is used as a heuristic to reduce the search effort in finding an optimal path to the goal node. An examination is made of Shen and Tsai's strategy and their complexity measure. The authors propose some simple alternatives to their algorithm that are effective in reducing the number of nodes generated (and expanded) without sacrificing the optimality criteria.>

The concept of a program which lists or enumerates all possible computer programs in a given language occurs frequently in the study of theoretical computer science topics such as computability and formal languages.This paper studies characteristics of such enumerations and presents a way to give students a better intuitive "feel" for this concept.A simple technique for enumerating programs is developed and is used to present the millionth computer program in an enumeration.

Codes are developed for detecting unidirectional errors in t bytes simultaneously (t-UBED) while also providing all unidirectional error detection (AUED). These classes of codes differ from purely all unidirectional error detecting codes in that the errors in one byte may be of the form 1 to 0, while in another byte they may be of the form 0 to 1. The codes utilize 2 B for parity check information. As an example, a code providing 3-UBED+AUED protection for up to 12 information bytes of 8 b each can be constructed.>

A design-theoretic approach to binary linear codes that are single-error correcting (SEC) and double-error-detecting (DED) with the capability of detecting any error within a single byte of even width w (BED) is developed. A construction of SEC-BED-DED codes from ordinary binary linear codes utilizing partial Steiner systems is given. The construction produces some codes with higher rates than those known previously. The codes constructed may inherit special properties from the Steiner systems from which are derived. In particular, some rotational odd-weight-column codes are obtained.>

Given any fixed linear block code, the error rates for the message symbols depend both on the encoding function and on the decoding map. This research shows how to optimize the choice of a generator matrix and decoding map simultaneously to minimize the error rates for all message symbols. The model used assumes that the distribution of messages is flat and that the distribution of error vectors defining the channel is independent of the message transmitted. In addition, it is shown that, with proper choice of coset leaders, standard array decoding is optimal in this circumstance. The results generalize previously known results on unequal error protection and are sufficiently general to apply when a code is used for error detection only.

SEC-ED-DED codes are single error correcting and double error detecting while simultaneously providing byte error detection. SEC-BED-DED codes are constructed for byte lengths of 5 and larger. For many byte lengths and code lengths, these codes require fewer check bits or have implementation advantages when compared to other SEC-BED-DED codes.

Error correcting codes, such as Hamming codes, have been used successfully to correct errors arising from failures in computer memories. Failure of a chip or card can cause errors which exceed the capabilities of these codes. We construct codes which detect any byte error and correct such errors if they are single random errors. A subclass of the codes developed is shown to have the additional capability of detecting double errors. These codes are intended for use when data are packaged on a byte per chip or a byte per card basis. The codes require fewer check bits than any previously known to the authors except when the byte length or number of bytes is small.