William I. Chang

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Given a text string of lengthn and a pattern string of lengthm over ab-letter alphabet, thek differences approximate string matching problem asks for all locations in the text where the pattern occurs with at mostk differences (substitutions, insertions, deletions). We treatk not as a constant but as a fraction ofm (not necessarily constant-fraction).(More)
We present the application of a nonrandom sequence-tagged site (STS) content detection method in mapping an entire genome, that of fission yeast. The novelty of our strategy is in the use of STS probes made from both ends of cosmid clones, selected on the basis of "sample without replacement" (only library clones that show no previous positive hybridization(More)
The role of Asp274 in inducer binding of lac repressor has been explored by spectroscopic measurements, fluorescence quenching, in vitro induction assays, and chemical modification of mutants with conservative substitutions at this site. Although no fluorescence emission shift or characteristic UV difference spectrum was observed at high inducer(More)
To explore the roles of three aspartate residues, Asp88, Asp130, and Asp274, found in the proposed inducer binding site of lac repressor [Sams, C. F., Vyas, N. K., Quiocho, F. A., & Matthews, K. S. (1984) Nature 310, 429-430], each site was substituted with alanine, glutamate, lysine, or asparagine by site-specific mutagenesis. The mutations at the Asp88(More)
Call a bypergraph simple if for any pair u, v of distinct vertices, there is at most one edge incident to both u and v, and there are no edges incident to exactly one vertex. A conjecture of Erd6s, Faber and Lovfisz is equivalent to the statement that the edges of any simple hypergraph on n vertices can be colored with at most n colors. We present a simple(More)
Acyl coenzyme A:cholesterol acyltransferase (ACAT) is an intracellular enzyme that catalyzes the formation of cholesterol esters from cholesterol and long-chain fatty acyl-coenzyme A. It is believed that ACAT plays a key role in lipoprotein metabolism and atherogenesis. Recently our laboratory succeeded in molecular cloning and functional expression of(More)
The Chinese language search engine Baidu.com is the fourth most trafficked web site in the world, in what will likely soon become the world's largest user-base, China. We will outline three key systems: search engine, iknow.baidu.com, and advertising platform, and describe open problems encountered in the continuing process to improve Baidu.com's technology(More)