Stephen R. Tate

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A Threshold Circuit consists of an acyclic digraph of unbounded fanin, where each node computes a threshold function or its negation. This paper investigates the computational power of Threshold Circuits. A surprising relationship is uncovered between Threshold Circuits and another class of unbounded fanin circuits which are denoted Finite Field ZP (n)(More)
In this paper, we consider a model of lossless image compression in which each band of a multispectral image is coded using a prediction function involving values from a previously coded band of the compression, and examine how the ordering of the bands affects the achievable compression. We present an efficient algorithm for computing the optimal band(More)
In this paper, we examine the problem of incrementally evaluating algebraic functions. In particular, if f(x1, x2, ..., xn) = (y1, y2, ..., ym) is an algebraic problem, we consider answering on-line requests of the form ―change input xi to value v‘‘ or ―what is the value of output yj?‘‘ We first present lower bounds for some simply stated algebraic problems(More)
Searching for a goal is a central and extensively studied problem in computer science. In classical searching problems, the cost of a search function is simply the number of queries made to an oracle that knows the position of the goal. In many robotics problems, as well as in problems from other areas, we want to charge a cost proportional to the distance(More)
We show that the ordering used in the sorting stage of the Burrows-Wheeler transform, an aspect hitherto ignored, can have a significant impact on the size of the compressed data. We present experimental results showing smaller compressed output achieved with two modifications to the sorting: using a better alphabet ordering and reflecting the sorted(More)
Intrusion detection systems (IDS) are responsible for monitoring and analyzing host or network activity to detect intrusions in order to protect information from unauthorized access or manipulation. There are two main approaches for intrusion detection: signature-based and anomaly-based. Signature-based detection employs pattern matching to match attack(More)
We consider the problem of keeping sensitive data and algorithms contained in a mobile agent from discovery and exploitation by a malicious host. The focus in this paper is on rigorous techniques based on cryptographic protocols. Algesheimer, Cachin, Camenisch, and Karjoth (IEEE Security and Privacy, 2001) devised a secure agent protocol in such a setting,(More)