There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

We conduct an exhaustive survey of image thresholding methods, categorize them, express their formulas under a uniform notation, and finally carry their performance comparison. The thresholding methods are categorized according to the information they are exploiting, such as histogram shape, measurement space clustering, entropy, object attributes, spatial correlation, and local gray-level surface. 40 selected thresholding methods from various categories are compared in the context of nondestructive testing applications as well as for document images. The comparison is based on the combined performance measures. We identify the thresholding algorithms that perform uniformly better over nonde- structive testing and document image applications. © 2004 SPIE and IS&T. (DOI: 10.1117/1.1631316)

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Survey over image thresholding techniques and quantitative performance evaluation

National Institute of Standards and Technology における超伝導研究及び生活

The objective of this paper is to give a comprehensive introduction to applied cryptography with an engineer or computer scientist in mind. The emphasis is on the knowledge needed to create practical systems which supports integrity, confidentiality, or authenticity. Topics covered includes an introduction to the concepts in cryptography, attacks against cryptographic systems, key use and handling, random bit generation, encryption modes, and message authentication codes. Recommendations on algorithms and further reading is given in the end of the paper. This paper should make the reader able to build, understand and evaluate system descriptions and designs based on the cryptographic components described in the paper.

[서평]「Applied Cryptography」

Discovery of association rules is an important problem in database mining. In this paper we present new algorithms for fast association mining, which scan the database only once, addressing the open question whether all the rules can be efficiently extracted in a single database pass. The algorithms use novel itemset clustering techniques to approximate the set of potentially maximal frequent itemsets. The algorithms then make use of efficient lattice traversal techniques to generate the frequent itemsets contained in each cluster. We propose two clustering schemes based on equivalence classes and maximal hypergraph cliques, and study two traversal techniques based on bottom-up and hybrid search. We also use a vertical database layout to cluster related transactions together. Experimental results show improvements of over an order of magnitude compared to previous algorithms.

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New algorithms for fast discovery of association rules

The problem of generating all the maximal independent sets (or maximal cliques) of a given graph is fundamental in graph theory and is also one of the most important in terms of the application of graph theory. In this paper, we present a new efficient algorithm for generating all the maximal independent sets, for which processing time and memory space are bounded by $O(nm\mu)$ and $O(n+m)$, respectively, where n, m, and $\mu$ are the numbers of vertices, edges, and maximal independent sets of a graph.

A New Algorithm for Generating All the Maximal Independent Sets

Thts paper deals wRh the problem of enumerating all the cutsets or all the s-t cutsets separatmg two spectfied verttces s and t m an undirected graph A vanety of approaches have been proposed for this problem, among which one based on the partmon e ra set of veruces rote two sets is the most effi¢ienL It is first shown that an algorithm of this type has time complexity O((n + m)(n log2#)#), and two new algorithms with ume complexity O((n + m)O + I)) are then proposed One of these new algorithms has space complexity O(nZ), and the other has space complexity O(n + m), where n and m are the numbers of veraces and edges, respectively, and ta ts the number ofs-t cutsets m a given graph The results of some computatmnal experiments are also described. An mvest~gaUon ~s made of the extent to whtch the new algorithms are better, and how good the performance of the old algorithm is, especmlly when a given graph is \"dense,\" t e , 2m/(n(n 1)) _> 0.4.

An Algorithm to Enumerate All Cutsets of a Graph in Linear Time per Cutset

A low-power processor architecture is described dedicatedly for embedded application programs by means of an object code compression approach. This approach unifies duplicated instructions existing in the embedded program and assigns a compressed object code to such an instruction. An instruction decompressor is constructed so as to generate an object code from each compressed object code (pseudo code) input. A single-chip implementation of this decompressor together with a processor core can effectively reduce the bandwidth required for the I/O interface. To demonstrate the practicability of the proposed approach, experiments are applied to an embedded processor ARM610 which attains 62.5% code compression, and hence 42.3% of the power consumption of instruction memory can be reduced.

/pdf/an-object-code-compression-approach-to-embedded-processors-qie9klwhb0.pdf

An object code compression approach to embedded processors

The multilayer routing problem is introduced and its relation to the single-row single-layer routing problem is illustrated [1], [2]. An easily implementable sufficient condition on the routability of a net list over a single row of nodes is presented. The solution is given by a constructive forward marching procedure and the result is an improvement over the worst-case prediction of So [1]. The implementation algorithm is programmed on CDC 6400 computer. The nature of the optimum criterion relating to single-row routability is investigated and a necessary and sufficient condition is given to characterize the nature of optimality. Some necessary conditions are also presented which can be used to evaluate the sufficient condition and served as a lower bound for the channel capacity in the routing problem. The more general routing problem is illustrated and possible future research directions are discussed.

The multilayer routing problem: Algorithms and necessary and sufficient conditions for the single-row, single-layer case

A multimicrocomputer system is described, stressing mainly software and hardware architectures, which has been constructed mainly for image creation. This system is distinctive mainly in that (i) 64 unit computers are interconnected with a root computer, each of equal performance, such that a number of unit computers constitute a pipelined computer and such pipelined computers work in parallel, all controlled by the root computer, and (ii) an intercomputer memory swapping unit is introduced, which is to be linked with a pair of unit computers to transfer a great amount of data at a time from one to the other through the use of a bus exchange switch.

Isao Shirakawa

Papers

A New Algorithm for Generating All the Maximal Independent Sets

An Algorithm to Enumerate All Cutsets of a Graph in Linear Time per Cutset

An object code compression approach to embedded processors

The multilayer routing problem: Algorithms and necessary and sufficient conditions for the single-row, single-layer case

Links-1 - a parallel pipelined multimicrocomputer system for image creation