Institutional Repository

The University of Houston Institutional Repository (UHIR) collects, preserves and distributes scholarly output and creative works produced by the University of Houston community. UHIR provides free and open online access to the university’s research and scholarship, including electronic theses and dissertations.


Recent Submissions

Tree classification and linking process in the seismogram
(1985) Lin, Zoung-Shan; Huang, Kou-Yuan; Pyle, L. Duane; Rajaram, Navaratna S.
Two purposes of this study are to use decision- theoretic pattern recognition for detecting the physical anomalies of seismic patterns and to use linking technique for linking seismic reflection patterns. Tree classification is used in decision-theoretic pattern recognition to the two-dimensional seismogram for the detection of physical anomalies in bright spot pattern, pinch-out pattern, and flat spot pattern. Using tree classifier, we get the 1-D classification result. In 2-D processing technique, linking process can extract the seismic patterns from the seismogram. Two methods are used in the linking process. One is the corresponding technique of the Levenshtein distance, the other is the proposed pattern growing technique. In the Levenshtein distance technique, a string-to-string minimum distance calculation is used for waveform correlation with the neighboring traces. In the pattern growing technique, the branch and bound search algorithm is used to find the best way to correlate the seismic reflectors. After obtaining the 1-D tree classification result, some singularities may still exist in the seismogram. These singularities can be removed with 2-D linking processing technique.
Implementation of vertically bounded propagation of privileges in a relational database system
(1985) Hwang, Ling-Jen; Leiss, Ernst L.; Elmasri, Ramez A.; Alavi, Maryam
With the ever-increasing use of computers for storing large volumes of vital data, in order to provide protection and data security, an authorization mechanism must permit information to be accessed only by properly authorized users. The Griffiths/Wade Authorization mechanism of IBM's System R assumes a relational database in which the information concerning grants with or without grant-option of privileges; E.L. Leiss first introduced and discussed the notion of bounded propagation of privileges. In our implementation, we will implement the authorization system with vertically bounded propagation of privileges in the relational database system REQUEST. Our main objective of implementing this authorization system is to determine whether a user is authorized to access a data object in a certain prespecified way, and if not how to prevent this unauthorized access within the framework of a given system or model.
On the number of queries necessary to identify a permutation
(1985) Teng, Shia-Chung; Ko, Ker-I; Anderson, Robert B.; Fajtlowicz, Siemion B.
Let p and q be two permutations of integers [1,2, ... ,n}. We denote by d(p,q) the number of integers i, 1
An experimental investigation of the space shuttle sonic boom
(1985) Stansbery, Eugene George; Benbrook, James R.; Gorman, Michael; Sheldon, William R.; McDonald, John A.
Theoretical methods exist for calculating the pressure signature, or sonic boom, of a maneuvering supersonic aircraft far from the flightpath. These methods are based on linearized geometric acoustics with nonlinear distortion and assume a horizontally stratified, time invariant atmosphere. The Space Shuttle, however, differs significantly in both its geometry and operational characteristics from typical supersonic aircraft. Measurements of the sonic boom pressure signature were made during the descent and landing of STS-41B and the ascent of STS-41D. These results have been compared with theoretical predictions based on the Waveform Parameter Method. The maximum overpressures measured generally agreed with calculated values to within 10-15%.
The relationship between perceived principal instructional leadership behavior and locus of control
(1988) Duryea, Margaret Bell; Hooker, Richard Lee; Hughes, Larry W.; Gaa, John P.; Borgers, Bill E.
The 1970's and 1980's brought about a myriad of studies investigating the essential elements of effective schools. Strong administrative leadership has been consistently identified by researchers as one of these essential elements. The purpose of this study was to investigate the relationship of perceived instructional leadership behavior of principals to the personal factor of locus of control which refers to a person's characteristic attributions regarding events and outcomes in his or her environment. In addition, the extent to which principals and their teachers agreed on the frequency with which instructional leadership behaviors were being used was analyzed. The variables of gender, length of service, and level of school were also investigated to seek their relationships to perceived instructional leadership behavior. The subjects in this study were 28 principals in a suburban school district in Houston, TX. A random sample of between 15 and 25 teachers in each of the 28 schools were asked to assess teacher perceptions of principal instructional leadership behavior. Two instruments were used to collect the primary data for this study: The Principal Instructional Management Rating Scale (Ballinger, 1986) and the I-E Scale (Rotter, 1966). A short questionnaire was used to collect the data on principal gender, length of service, and the level of school. [...]