Legacy Theses and Dissertations (1940-2009)

Permanent URI for this collectionhttps://hdl.handle.net/10657/6771

This collection gathers digitized University of Houston theses and dissertations dating from 1940.

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Controlled-release topical polymeric formulations of anthralin
(1984) Wang, Tsu-I; Chow, Diana Shu-Lian; Feldman, Stuart; Kramer, William G.; Eikenburg, Douglas C.
Five topical polymeric formulations of anthralin were fabricated with two types of silicone elastomers and various additives, containing 5% (W/W) of anthralin. The objectives were to provide a transdermal controlled-release mechanism with which the rate limiting step of percutaneous penetration was built into the polymeric device rather than stratum corneum as with conventional dosage forms, and to overcome the problems of chemical instability and irritation to normal skin, inherent to conventional dosage forms. Product asscessments were conducted, including (1) weight, thickness and anthralin content uniformities, (2) in vitro anthralin release kinetics from the polymer and (3) in vitro anthralin penetration through and disposition in hairless mouse skin after 48 hours of application. The results provided guidelines for future product development and refinement. An HPLC assay was developed with reversed-phase octyl column, mobile phase of acetonitrile/water mixture, capable of measuring amount as low as 5 ng of anthralin. The assay was employed in all studies of content uniformity, stability, drug release, and drug penetration. The release process of anthralin from formulated polymer followed the first-order kinetics which is the characteristic of matrix-type of controlled-release device. Anthralin had a larger diffusion coefficient through the 382 silicone elastomer than through MDX-4-4210 silicone polymer. The glycerol, azone, and propylene glycol incorporated in various polymeric formulations did not affect the diffusion coefficient of anthralin in test silicone elastomer. The extent of anthralin penetration from 382 silicone elastomer into hairless mouse skin was significantly higher than that from MDX-4-4210 silicone elastomer. The incorporation of Azone and glycerol in 382 silicone polymer did not improve percutaneous penetration of anthralin from the polymer, while propylene glycol increased anthralin penetration from MDX-4-4210 silicone elastomer significantly. Anthralin degradation might not be a simple first-order process where oxygen might play a role. Azone facilitated anthralin oxidation, and Vitamin C significantly stabilized anthralin in conventional vehicle. However, when anthralin was incorporated in polymeric formulations, the degradation process was further slowed down. All formulated polymers served the purpose of preventing anthralin from decomposition.
The synthesis, 13C-NMR spectroscopy and molecular structures of novel azathianthrene analogs
(1984) Lam, Wing-Wah; Martin, Gary E.; Alam, Maktoob; Ternay, Andrew L., Jr.; Weinheimer, Alfred J.; Willcott, Mark Robert, III
Syntheses of 2-azathianthrene (39), benzo[bl] ,4-diazathianthrene (51), 1,4-diazathianthrene (58), 1,3-diazathianthrene (62), l-oxo-1,2- dihydro-2,3-diazathianthrene (68), l-chloro-2,3-diazathianthrene (69) and 4-methoxy-l ,2-diazathianthrene (75) are reported. All of these compounds were analyzed with proton and carbon nmr spectroscopy. Both benzo[b]-l ,4-diazathianthrene (51) and 1,4-diazathianthrene (58) were also examined using X-ray crystallographic techniques. [...]
Pharmacological analysis of the actions of calcium entry blockers, felodipine, nifedipine and verapamil : interactions with pre- and postjunctional alpha adrenoceptors
(1984) Peter, Eno-Obong J.; Lokhandwala, Mustafa F.; Eikenburg, Douglas C.; Jandhyala, Bhagvan S.; Alam, Maktoob
The objective of the present study was to investigate the role of the autonomic nervous system in the hypotensive actions of the calcium entry blockers, felodipine, nifedipine and verapamil. Experiments were designed to determine the effects of these compounds on vascular sympathetic neuroeffector function under both in vivo and in vitro conditions. Intravenous administration of cumulative doses of felodipine in intact urethane anesthetized rats produced a sustained and significant decrease in arterial pressure up to 60 minutes in duration at the highest dose (0.8 [micromol]/kg) tested. Higher doses of nifedipine (0.9 [micromol]/kg) and verapamil (0.9 [micromol]/kg) produced transient but significant decreases in mean blood pressure which lasted for 10 minutes. When cardiac compensation was prevented by either bilateral vagotomy plus atropine (1 mg/kg) or propranolol (1 mg/kg) alone or bilateral vagotomy together with atropine plus propranolol, nifedipine and verapamil were also able to reduce arterial pressure. However after ganglionic blockade (chlorisondamine plus atropine) only felodipine was effective in lowering arterial blood pressure. In pithed rat preparations felodipine (0.5 [micromol]/kg), nifedipine (1.2 [micromol]/kg) and verapamil (0.9 [micromol]/kg) significantly attenuated pressor responses to spinal sympathetic stimulation and exogenous norepinephrine. While all three agents attenuated blood pressure responses to norepinephrine as well as spinal stimulation, felodipine appeared to be more effective in reducing pressor responses to intravenous norepinephrine than those of spinal stimulation. [...]
Recent foraminifera around petroleum production platforms on the southwest Louisiana shelf
(1981) Locklin, Jo Ann; Maddocks, Rosalie Frances; Evans, Ian; Bryant, Edwin H.
The Gulf of Mexico outer continental shelf off the southwest Louisiana coast is an area of heavy offshore petroleum production. Six hundred and seventy-three samples were taken from around petroleum production platforms and control sites in the area, in order to assess the effects of petroleum exploration, drilling, and production activity on the marine organisms. A total of 64,326 living foraminifera were recovered, representing 51 species in 35 genera. Densities up to 372,154 foraminifera per 10 cm2 were estimated for the summer, partly caused by the large quantities of available food supplied by the Mississippi River, and partly caused by the wet picking method which preserved delicate juvenile tests. Nonionella basiloba and Buliminella bassendorfensis together account for almost 76% of the total live foraminiferal population. Slight seasonal variations in the foraminifera population were found. Changes in species composition at the collecting sites are closely related to water depth. Low standing crops at the shallow inshore stations in the summer were primarily caused by low dissolved oxygen. Low diversity values, generally not exceeding [alpha]=5, were found for the foraminifera populations. The low diversity is caused by the large range of seasonal temperatures, movement of sediment by currents and tides, and, to a lesser degree, the variations in salinity. Negative effects of petroleum drilling operations on the benthonic foraminifera are not supported by this study. The controlling physical factors on the foraminifera populations are those related to the natural environment, water depth, temperature and salinity, tides and currents, and dissolved oxygen.
Biochemical studies of Deoxyadenosine in L1210 cells
(1983) Kang, Gil-Jong; Kimball, Aubrey P.; Gray, Horace B., Jr.; Tu, Shiao-Chun; Nelson, Daniel A.; Bear, John L.
The combination of 2'-deoxyadenosine and deoxycoformycin is known to be markedly toxic to T-lymphocyte cell lines relative to B-cell lines and this difference appears to be related to the capacity of the cells to accumulate dATP. In the presence of dipyridamole and 2'-deoxyadenosine and when adenosine deaminase was inhibited with deoxycoformycin, the L1210 leukemia cell which is a non-T, non-B cell type accumulated dATP like a T-cell type. The intracellular L1210 dATP levels using the triple combination (1.1 [micrometers] deoxycoformycin, 40 [micrometers] deoxyadenosine, 10 [micrometers] dipyridamole) reached 360 nmol/10[^9] cells at which concentration ribonucleotide reductase specific activity was reduced by 80%. In addition to the increase in dATP levels, intracellular L1210 2'-deoxyadenosine levels as high as 375 nmol/10[^9] cells were obtained with the triple combination.
Three-dimensional seismic modeling : velocity analysis and interpretation
(1981) Liang, Luh-Cheng; McDonald, John A.; Hilterman, Fred J.; Chafetz, Henry S.; Gardner, Gerald H. F.; Sheriff, Robert E.
In this research, interpretations based on theoretical and physical modeling data are given in the hope that they can be useful to the seismic interpreter for discerning pitfalls in real data. Recognition of these pitfalls could be an additional aid in the area of seismic interpretation. As for the theoretical modeling, several interpretational pitfalls were identified when a systematic analysis was carried out with respect to three basic geological structures: basins, domes and partial reflectors. The pitfalls identified include: apparent pinchouts and grabens which were related to the profile line direction; extra reflection layers related to the depth of the model and the areal size of the structure; cross-stratifications related to the profile line direction and the areal size of the structure; faults or extra events related to the data acquisition schemes; weak events related to the processing flow; apparent "ambient noise" related to structural dip change; etc. As for physical modeling, both the lateral and vertical velocity variations in a 3-D environment were evaluated and several pitfalls were identified. These pitfalls include: a dim spot which was related to an overlying high-velocity lens; a bright spot related to an overlying low velocity lens; an apparent velocity pullup where actually a velocity pushdown should be observed; a low frequency disturbed zone under the lens having a high velocity contrast; the "thick lens" effect which distorted the appearance of the true structure; the wave conversion within sharply curved 3-D structures which is yet an unsolved problem of converted wave; ghost events which result from wavelet processing; etc. Also in this research, three different velocity analysis algorithms were developed and evaluated for areally gathered seismic data. The first velocity algorithm was designed for data gathered by closely spaced conventional GDP lines. An optimum stacking velocity along with the apparent dip were obtained. The second velocity algorithm was designed for areal common-mid-point data. A migration velocity along with strike and dip were obtained. The third velocity algorithm was designed for multi-midpoint data such as would be gathered in a crooked-line survey. An optimum stacking velocity as a function of dip and strike and a final migration velocity were obtained. These velocity algorithms offered a new processing flow which was applied on the crooked-line data using the output parameters derived from the third velocity algorithm. A satisfactory depth reconstruction was obtained and it proved that the processing flow and velocity algorithm were correct.
Metabolism of phenanthrene by the rat and the guinea pig
(1984) Lertratanangkoon, Khingkan; Middleditch, Brian S.; Horning, Marjorie G.; Eichberg, Joseph, Jr.; Fox, George E.; OroÌ�, John F.; Zlatkis, Albert
The metabolism of phenanthrene has been studied in the rat and the guinea pig, with the aim of seeking evidence in whole animals of the formation of dihydrodiol epoxides and/or diepoxides as metabolic intermediates and of comparing the bivalent sulfur metabolites excreted by the two species. After the administration of phenanthrene (50 mg/kg, ip) to young adult male rats and guinea pigs, a series of oxygenated- and bivalent sulfur-containing metabolites were isolated and identified by GC and GC/MS. Thirty-four oxygenated metabolites were isolated after enzymatic hydrolysis of the urine samples from the rat, whereas only twenty-one were detected in guinea pig urine. The major metabolites in both species were identified as 9,10- and 1,2-dihydrodiols, indicating that both K-region and non-K-region pathways are highly operative in vivo. Several triols and tetrols were also isolated as urinary metabolites, suggesting that dihydrodiol epoxides and/or diepoxides are involved in the metabolism of phenanthrene by the rat and the guinea pig. Besides the oxygenated metabolites, seven methylthio metabolites were isolated from the neutral fraction of hydrolyzed rat urine, whereas only two were detected in guinea pig urine. The major methylthio metabolite excreted by each species was 9-hydroxy-10-methylthio-9,10-dihydro- phenanthrene. This was observed as a second-day metabolite in the rat, and its appearance was accompanied by 9-hydroxyphenanthrene. Acidic urinary metabolites derived from glutathione conjugates are species-dependent. The major metabolite in hydrolyzed rat urine was N-acetyl-S-(9-hydroxy-9,10-dihydro-10-phenanthryl)-L-cysteine. In the guinea pig, the major bivalent sulfur acid was S-(9-hydroxy-9,10-dihydro- 10-phenanthryl)mercaptoacetic acid, but N-acetyl-S-(9-hydroxy-9,10-dihydro- 10-phenanthryl) -L-cys teine was also present. The excretion of S-(9-hydroxy-9,10-dihydro-10-phenanthryl)mercaptoacetic acid by the guinea pig may be due to incomplete acetylation or to a combination of acetylation and deacetylation of cysteine or cysteinylglycine adducts.
A knowledge based approach to planning in card games
(1987) Lo, Pai-Yen; Eick, Christoph F.; Rusinkiewicz, Marek; Fajtlowicz, Siemion B.
The purpose of this research is to explore computational approaches to the planning in card games. Because of the complexity of the problem, the study was restricted to the Declarer playing in a NT-contract in Bridge. A program has been provided which simulates the planning process of a human player. It uses a knowledge based approach which encodes knowledge in form of rules and in form of plans. The program uses rules to select playing techniques for each suit held in the player's hand during static analysis and to guide a small tree search which confirms a particular technique is best. Once a technique is selected, the plans are used to construct the playing sequence of cards for this technique. The possibilities and limitations of the overall approach are discussed.
Heterogeneous distributed database management : RIM-Oracle interface
(1987) Wong, Ngiam Woon; Huang, Stephen S. H.; Elmasri, Ramez A.; Wu, Tiee-Jian
This thesis develops a database interface between two relational database management systems such that they can be viewed as a heterogeneous distributed database management system. The RIM-Oracle interface system allows a user to transparently access the Oracle DBMS through the RIM DBMS, where the two DBMS are located in different computers connected by a computer network. The RIM-Oracle interface system allows a user to setup a data dictionary with information about existing relations stored in RIM and Oracle, and then perform RIM database retrieval and relational algebra queries on the relations. An interface program is build on top of each DBMS, and the two programs communicate over the network to perform their tasks. The host DBMS, RIM, is independent of the remote DBMS, Oracle, whereas the remote DBMS is dependent on the host DBMS, although the dependence is limited. Since the host DBMS is independent of the remote DBMS, the interface system can be extended to allow queries involving other DBMSs, located in other nodes of the network, using the methods developed in this thesis.
A comparative study of height-balanced tree
(1987) Wang, Ronghuey Alice; Huang, Stephen S. H.; Simpson, Anne L.; Wu, Tiee-Jian
Height-balanced trees (H-trees), a recently proposed data structure, is a variant of B-trees. An H([beta], [gamma], [delta]) tree is defined by three parameters: [beta], the size of a node; [gamma], the minimal number of grandsons which a node must have; and [delta], the minimal number of leaves which bottom nodes must have. The purpose of this research is to study H-trees empirically. Algorithms, to insert and delete elements, are implemented. The results of our experiments confirm the validity of existing theories. For example, by varying the parameters [delta] and [gamma], significant changes in the tree's performance are observed: the height of H-trees decreases as [gamma] increases, and the storage utilization increases as [delta] increases. Moreover, comparisons of H-trees with other variants of B-trees are shown to demonstrate the superiority of H-trees. Specifically, the average storage utilization of H-trees may be higher than that of B-trees by almost 20%.
An efficient fault tolerant distributed shortest path program in ADA
(1987) Malik, Camron; Lee, Pen-Nan; Huang, Stephen S. H.; Wu, Tiee-Jian
A simple, elegant algorithm upon implementation presents innumerable problems. This paper provides insight into the difficulties of implementing a distributed algorithm. This is followed by an efficient, fault tolerant implementation of the Distributed Shortest Path Algorithm. The provision of fault tolerance has a large overhead in terms of the number of messages required. A modification of the algorithm is proposed to reduce the number of messages, using buffering in conjunction with Ada constructs to achieve this in the implementation. The unrestricted communication in a distributed system produces situations conducive to deadlock. This is particularly true if a synchronous form of message passing is used, as processes will wait indefinitely for each other. To ensure freedom from deadlock a variant of nondeterministic message sending based on Ada timed out entry calls is used. Distributed programs are also, by virtue of their complexity, difficult to verify. Even after extensive testing residual design inadequacies may be present Thus the concept of Communication Closed Layers is used to design the program. The Consensus-Global Tester is used to implement error detection and assist in error recovery. In the event of an error, a Backward error recovery scheme is used which saves the essential information. Thus, computation can be reinitiated using the saved values.
A portable graphics package for three-dimensional surface reconstruction
(1987) Wing, Yu Ping; Pieroni, Goffredo G.; Elmasri, Ramez A.; Dhawan, Atam P.
The CORE protocol provides a list of standard features for constructing a program in dealing with two-dimensional and three-dimensional object representations. The most important features of a such system are linear transformation, windowing, clipping, viewing transformation, projection, hidden-line elimination and hidden-surface removal. In this thesis, the implementation of the CORE system is based on Steven Harrington's book "Computer Graphics - A Programming Approach" by McGraw Hill. A list of basic algorithms is critically analyzed. Errors were discovered in some important algorithms as proposed by Harrington. A corrected version is presented and implemented. Finally a set of experiments for constructing 3D objects has been performed by using different output devices : Lexidata, Tektronix and Printronix. The principal one consists of displaying a 3D surface of a human heart obtained by a sequence of PET images.
Byzantine agreement : algorithms and applications
(1987) Zhao, Yi; Bastani, Farokh B.; Leiss, Ernst L.; Wu, Tiee-Jian
All participating processes in a distributed system often have to reach agreement of some kind. The presence of malicious faults can cause a faulty process to send conflicting messages to different processes, making it difficult for nonfaulty processes to reach agreement. This problem, often called Byzantine agreement, Byzantine generals problem, or interactive consistency, is important in both the theory and practice of distributed computing and has been the subject of intense research in recent years. This thesis presents a comprehensive study of this problem and its various applications. The Mostly Byzantine agreement is proposed as a less restrictive model for process-control applications. It can achieve a high degree of fault tolerance with a relatively low cost.
A file interface and data dictionary for the ECRDBS high level database system
(1987) Wu, Yu-Tung; Elmasri, Ramez A.; Huang, Stephen S. H.; Deming, Stanley N.
The Entity-Category-Relationship (ECR) data model captures important descriptive semantics of a database, such as generalization hierarchies and attribute inheritance. Since no complete ECR DBMS has been implemented before, an ECR DBMS, called ECRDBS, is implemented to demonstrate the usefulness of the above data modeling concepts. This thesis describes the design and implementation of two components of ECRDBS; the file interface and the data dictionary system. In the first part of the thesis, the indexed file organization on the VAX/VMS system is used to implement a file interface which provides basic, record at a time, file commands for storage, retrieval and updating of information. In the second part of the thesis, a data dictionary system based on the ECR model is implemented. It is responsible for parsing the data definition statements for a particular database and creation of data dictionary files. Function procedures are provided for the user and other components of the ECRDBS system to access the information stored in the data dictionary files.
Remote terminal access to a VAX/VMS system in a heterogenous network system
(1987) Yiu, Shoou Jiah; Bahaa-El-Din, Wael; Elmasri, Ramez A.; Markenscoff, Pauline
In a heterogenous network system consisting of computers of different makes, there is a need for remote terminal access and internet file transfer. The topic of the thesis concentrates on the design and implementation of remote terminal access from any computer to a VAX/VMS system. The only prerequisite condition is that the computer - the remote node - which accesses the VAX/VMS node - the host node - be on the same heterogenous network system based on the ETHERNET standard. The strength of this design is a fully VMS compatible terminal driver that provides all the screen-oriented capabilities of a DEC VAX/VMS Terminal Driver. Also, its design involves terminal server functions to manage the total number of remote logons, and provides clean recovery from different cases of remote access failure. The design concentrates the bulk of the code on the VAX/VMS system, thereby allowing relatively easy implementation of remote terminal access on any remote node. The remote node need only to implement a terminal emulator and necessary modules to facilitate the same internet communication protocol as this implementation.
Algorithms for manipulating triangulated surfaces
(1987) Yiu, Dang-Cheng; Simpson, Anne L.; Elmasri, Ramez A.; Sanders, Richard
Triangulations are powerful tools for surface modeling. They can be used to fit any irregular boundary shapes and surface discontinuity fault patterns. However, without the help of row and column information as in rectangular grids, manipulating a triangulated surface interactively is not an easy task. Efficiency is a major concern for manipulation functions. This article will propose some algorithms to manipulate triangulated surfaces such as: finding the path of a given route in a triangulated surface; getting the profile of a vertex function along a given route; and partitioning a surface domain by vertical plane(s). These algorithms have applications to interactive graphics where the user wishes to slice multisurface folds to obtain various views of a solid, and to dynamical problems where one wishes to introduce fracture systems into pre-existing surfaces. Some other useful operations such as merging of two domains, moving a vertex with preset rules, and combined use with rectangular grids, are also discussed. The proposed algorithms have been implemented in a triangulation database system developed by W.M. Smith of Cullen Image Processing Laboratory at University of Houston. This process requires both expansion and modification of Smithâ€™s system. The principal modification introduced enables the system to treat multiple surfaces in main memory rather than only one surface at a time from a file database. The algorithms can be applied to any multi-connected surface domain. Holes and irregular boundary conditions are given careful treatment A theoretical analysis of time complexity is not available at this stage. Empirical results for the time required by these algorithms are given instead.
Design considerations for large distributed electronic mail systems
(1987) Yuen, Hui-Tung; Bahaa-El-Din, Wael; Lee, Pen-Nan; Wu, Tiee-Jian
Electronic mail is one of the most important means for communication and information exchange in internetworking environments. In this thesis, three methodologies for designing large mail systems are investigated, namely, mail systems with syntax-directed naming, mail systems with location-independent access, and attribute-based mail systems. Mail systems with syntax-directed naming identify users by names which are syntactically structured according to user locations. Algorithms for load balancing among mail servers, system reconfiguration, and efficient message delivery are developed and are tested using simulation. Mail systems with location-independent access allow users to access them from different locations. Procedures for keeping track of migrated users and redirecting their mail are presented. The attribute-based mail system provides maximum flexibility to users by allowing them to identify one or more mail recipients by attributes instead of only by precise names. It can also be used in mass distribution of electronic mail. An algorithm for efficient broadcasting and searching using Minimum-weight Spanning Tree (MST) is investigated. Criteria for evaluating electronic mail systems are presented. Simulation experiments are used to test the procedures and algorithms, and to study the performance of the three mail systems.
Terminally directed hydrolysis of duplex ribonucleic acid catalyzed by a species of the BAL 31 nuclease from Alteromonas espejiana
(1983) Bencen, Gerard Henri; Gray, Horace B., Jr.; Fox, George E.; Kimball, Aubrey P.; Wagner, Michael J.
The extracellular nuclease activities of Alteromonas espejiana sp. BAL 31 are mediated by at least two distinct protein species that differ in molecular weights and catalytic properties. The two species that have been purified to homogeneity and characterized, the "fast" (F) and "slow" (S) enzymes, both possess an exonuclease activity that shortens both strands of duplex DNA, with the F nuclease displaying a much greater (approximately 27-fold) turnover number for this degradation than the S species. In the present thesis, it is shown that the F species also mediates the terminally directed hydrolysis of a linear duplex RNA, gradually shortening molecules of this substrate through a mechanism that results in the removal of nucleotides from both the 3' and the 5' ends. This degradation proceeds with very infreguent introduction of scissions away from the termini as demonstrated by gel electrophoretic examination of the products of partial degradation, both in duplex form and after denaturation by reaction with CH3HgOH, and by electron microscopic characterization of duplex partially degraded molecules. Tha apparent Michaelis constant and turnover number have been determined. At eguimolar enzyme concentrations in the limit of high substrate concentration, the F nuclease will degrade duplex RNA at a rate 0.019 [plus-minus] 0.004 times that for a duplex DNA of comparable guanine + cytosine content. The S species, by contrast, showed very little activity against the duplex RNA substrate in the photometric assay.
A multitasking implementation of a 3D high order finite difference forward modeling program on the CRAY X-MP/416
(1987) Terki-hassaine, Omar S.; Leiss, Ernst L.; Gardner, Gerald H. F.; Pyle, Leonard Duane
We present a multitasked implementation of a 3D out-of-core seismic forward modeling on the CRAY XMP/416. The algorithm is based on the forward explicit high order finite difference method. We give a brief theoretical overview of 3D forward modeling and the resolution of the 3D wave equation. We discuss the coefficient matrix generated by the above mentioned approach. An in-core and an out-of-core version of a reentrant subroutine were designed to perform any fraction of the matrix vector multiplication independently. The rest of the program takes advantage of the microtasking feature which enables the system to treat independent iterations of Do Loops as subtasks to be performed by any available processor. The comparison of the measured speed-ups obtained of the multitasked programs (two, three, and four processors) versus the unitasked programs shows that the combination of the macrotasking and microtasking features enabled us to reach approximately 80 percent of the ideal speed-up. The modeling results are significantly improved by using the absorbing boundaries. We tested the program to determine the number of points per wavelength. We found that the number of grid points per wavelength is inversely proportional to the order of the finite difference; and this led us to conclude that there is a significant reduction in memory requirements and in CPU time for using higher order. We discuss the effect of the elimination of a point from the high order configuration on the modeling result and the execution time. We show why the only acceptable result is when the outer point is eliminated. Finally the time sections of the SALFRH model collected at the plane Z = 3 are presented when we have a point source and a plane wave source in the model and for the exploding reflector model. Due to the availability of the SSD (Solid State Storage Device) and its 1250 Mbps dual channel, the I/O wait time was virtually close to zero.
Data management for knowledge-based systems
(1987) Law, Kam Man; Eick, Christoph F.; Elmasri, Ramez A.; Scamell, Richard W.
In recent years, expert systems have gained a large popularity in Computer Science as a result of the improvement made in Artificial Intelligence research and the announcement of the fifth generation computers. However, the design and implementation of large computerized knowledge bases have raised new data management problems. This thesis explores the new problems facing conventional Data Base Management Systems (DBMSs). It surveys the knowledge representation in Databases, Artificial Intelligence, and Programming Languages in order to search representation schemes for DALI, a Knowledge Base Management System. The concepts of DALI are discussed and the data model S-diagram used for knowledge base design is described. Furthermore, the features of DALI are compared with those of DBMSs; the advantages and disadvantages of DALI are examined. In its first version, the framework of DALI contains a schema compiler, a pattern matcher, and a storage structure program. The design and implementation of these essential components are described in detail.

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