Godfrey Dewey

Bio: Godfrey Dewey is an academic researcher. The author has contributed to research in topics: Spelling reform. The author has an hindex of 1, co-authored 1 publications receiving 181 citations.

A fast string searching algorithm

Abstract: An algorithm is presented that searches for the location, “il” of the first occurrence of a character string, “pat,” in another string, “string.” During the search operation, the characters of pat are matched starting with the last character of pat. The information gained by starting the match at the end of the pattern often allows the algorithm to proceed in large jumps through the text being searched. Thus the algorithm has the unusual property that, in most cases, not all of the first i characters of string are inspected. The number of characters actually inspected (on the average) decreases as a function of the length of pat. For a random English pattern of length 5, the algorithm will typically inspect i/4 characters of string before finding a match at i. Furthermore, the algorithm has been implemented so that (on the average) fewer than i + patlen machine instructions are executed. These conclusions are supported with empirical evidence and a theoretical analysis of the average behavior of the algorithm. The worst case behavior of the algorithm is linear in i + patlen, assuming the availability of array space for tables linear in patlen plus the size of the alphabet.

Language and Communication

Abstract: Presents eight specially written chapters which provide a coherent survey of major issues in the study of language and communication, and which show how these are related to questions of practical concern in the learning and teaching of second and foreign languages. The issues discussed have been selected primarily for their relevance to applied linguistics, and there is a unifying interest in how language reflects the communicative functions it performs as well as in the process involved in using language for communication. Each chapter presents a self-contained survey of a central issue, is prefaced by an introduction linking the different perspectives, and is followed by discussion questions to aid effective use of the text in applied linguistics courses.

Speech Analysis, Synthesis and Perception

Abstract: The first edition of this book has enjoyed a gratifying existence. 1s sued in 1965, it found its intended place as a research reference and as a graduate-Ievel text. Research laboratories and universities reported broad use. Published reviews-some twenty-five in number-were universally kind. Subsequently the book was translated and published in Russian (Svyaz; Moscow, 1968) and Spanish (Gredos, S.A.; Madrid, 1972). Copies of the first edition have been exhausted for several years, but demand for the material continues. At the behest of the publisher, and with the encouragement of numerous colleagues, a second edition was begun in 1970. The aim was to retain the original format, but to expand the content, especially in the areas of digital communications and com puter techniques for speech signal processing. As before, the intended audience is the graduate-Ievel engineer and physicist, but the psycho physicist, phonetician, speech scientist and linguist should find material of interest."

Signature files: an access method for documents and its analytical performance evaluation

Abstract: The signature-file access method for text retrieval is studied. According to this method, documents are stored sequentially in the \"text file.\" Abstractions (\"signatures\") of the documents are stored in the \"signature file.\" The latter serves as a filter on retrieval: It helps in discarding a large number of nonqualifying documents. In this paper two methods for creating signatures are studied analytically, one based on word signatures and the other on superimposed coding. Closed-form formulas are derived for the false-drop probability of the two methods, factors tha t affect it are studied, and performance comparisons of the two methods based on these formulas are provided.