Data structures for set manipulation- hash table, 1986

The most important issue addressed in this thesis is the efficient implementation of hash table methods. There are credential trade-offs in a desired implement ion. These are discussed in issues such as hash addressing, handling collision, hash table layout., and bucket overflow problems. The criteria of good hash function is providing even distribution. Collision is the major problem in hash table methods. Two major hashtable methods are discussed. Open Addressing Method places the synonymous items somewhere within the table. The Chaining Method, however, chains all synonymies and stores them somewhere outside the table called overflow area. Hash table is widely used by system software as an ideal data structure. Hash Table -applications canbe found in compiler's symbol table, database, directories of file organizations, as well as in problem-solving application programs

The relative value of recall and recognition techniques for measuring precise knowledge of word meaning nouns, verbs, adjectives

Thesis (Ed.D.)--Boston University. This item was digitized by the Internet Archive

Internal hashing for dynamic and static tables

This tutorial discusses one of the oldest problems in computing: how to search and retrieve keyed information from a list in the least amount of time. Hashing - a technique that mathematically converts a key into a storage address - is one of the best methods of finding and retrieving information associated with a unique identifying key. We briefly survey techniques which have evolved over the past 25 years and then introduce more recent research results for extremely compact and fast methods based on per­fect and minimal perfect hashing. Perfect and minimal perfect hashing is useful for rapid lookup in a static table such as keywords in a compiler, spelling checkers, and database management systems. The results presented here show techniques for constructing long lists which can be searched in one memo­ry reference.KEYWORDS AND PHRASES: Key-to-address transformation, hash coding, hash table, scatter table, bucket hashing, perfect hashing, minimal perfect hashin

Term-driven E-Commerce

Die Arbeit nimmt sich der textuellen Dimension des E-Commerce an. Grundlegende Hypothese ist die textuelle Gebundenheit von Information und Transaktion im Bereich des elektronischen Handels. Überall dort, wo Produkte und Dienstleistungen angeboten, nachgefragt, wahrgenommen und bewertet werden, kommen natürlichsprachige Ausdrücke zum Einsatz. Daraus resultiert ist zum einen, wie bedeutsam es ist, die Varianz textueller Beschreibungen im E-Commerce zu erfassen, zum anderen können die umfangreichen textuellen Ressourcen, die bei E-Commerce-Interaktionen anfallen, im Hinblick auf ein besseres Verständnis natürlicher Sprache herangezogen werden

Physical workload and musculoskeletal symptoms in the human-horse work environment

Most work in horse stables is performed manually in much the same way as a century ago, with old-fashioned tools and equipment. It is one of the least mechanised sectors dealing with large animals, which often involves work in awkward postures and lifts of heavy loads. However, there is a lack of knowledge of the ergonomic risks in the human-horse work environment. This thesis seeks to provide a deeper understanding of the human-horse work environment, work tasks, workload and frequency of musculoskeletal symptoms and to identify potential risk factors for the development of musculoskeletal symptoms. Self-reporting methods (questionnaires, rating scales), observation methods (OWAS, REBA), descriptive task analysis (HTA, HA, GTS) and biomechanical analysis (JACK) were used to collect and analyse data. Riding instructors surveyed in the questionnaire study reported high levels of perceived musculoskeletal symptoms in at least one of nine anatomical areas during the past year and the past week. The most frequently reported problem areas were the shoulders, the lower back and the neck. Mucking out stables was considered to be the task involving the heaviest work. OWAS analysis showed that three work tasks contained a high proportion of unacceptably awkward work postures, namely mucking out, preparing bedding and sweeping. During mucking out and sweeping, the back was bent and twisted for most of the time. There were many high-risk operations involved in mucking out boxes and disposing of bedding material. Emptying a wheel barrow on the muck heap included high-risk operations with awkward postures such as twisted, bent back arms over shoulder level and handling high loads. The analytical methods used clearly revealed where in the work tasks the ergonomic problems occurred. In almost all operations with a high risk level, a shafted tool or wheelbarrow was used. Analysis of the shaft length of two hand-held tools used for mucking out (manure fork, shavings fork) showed that the manure fork should have a longer shaft to reduce loading on the back. The results for the shavings fork were inconclusive, but indicated the importance of changes in work technique. More in-depth knowledge of the musculoskeletal symptoms and work tasks performed in the human-horse work environment makes it easier to plan and implement measures to prevent musculoskeletal symptoms in this particular group of workers