Search Results

Smoothing the information seeking path: Removing representational obstacles in the middle-school digital library.

Description: Middle school student's interaction within a digital library is explored. Issues of interface features used, obstacles encountered, search strategies and search techniques used, and representation obstacles are examined. A mechanism for evaluating user's descriptors is tested and effects of augmenting the system's resource descriptions with these descriptors on retrieval is explored. Transaction log data analysis (TLA) was used, with external corroborating achievement data provided by teachers. Analysis was conducted using quantitative and qualitative methods. Coding schemes for the failure analysis, search strategies and techniques analysis, as well as extent of match analysis between terms in student's questions and their search terms, and extent of match analysis between search terms and controlled vocabulary were developed. There are five chapters with twelve supporting appendixes. Chapter One presents an introduction to the problem and reviews the pilot study. Chapter Two presents the literature review and theoretical basis for the study. Chapter Three describes the research questions, hypotheses and methods. Chapter Four presents findings. Chapter Five presents a summary of the findings and their support of the hypotheses. Unanticipated findings, limitations, speculations, and areas of further research are indicated. Findings indicate that middle school users interact with the system in various sequences of patterns. User groups' interactions and scaffold use are influenced by the teacher's objectives for using the ADL. Users preferred to use single word searches over Boolean, phrase or natural language searches. Users tended to use a strategy of repeating the same exact search, instead of using the advanced scaffolds. A high percent of users attempted at least one search that included spelling or typographical errors, punctuation, or sequentially repeated searches. Search terms matched the DQ's in some instantiation 54% of all searches. Terms used by the system to represent the resources do not adequately represent the user groups' information needs, however, ...
Date: May 2002
Creator: Abbas, June M.
Partner: UNT Libraries

The Effect of Average Grain Size on Polycrystalline Diamond Films

Description: The work function of hydrogen-terminated, polycrystalline diamond was studied using ultraviolet photoelectron spectroscopy. Polycrystalline diamond films were deposited onto molybdenum substrates by electrophoresis for grain sizes ranging from 0.3 to 108 microns. The work function and electron affinity were measured using 21.2 eV photons from a helium plasma source. The films were characterized by x-ray photoelectron spectroscopy to determine elemental composition and the sp2/sp3 carbon fraction. The percentage of (111) diamond was determined by x-ray diffraction, and scanning electron microscopy was performed to determine average grain size. The measured work function has a maximum of 5.1 eV at 0.3 microns, and decreases to 3.2 eV at approximately 4 microns. Then the work function increases with increasing grain size to 4.0 eV at 15 microns and then asymptotically approaches the 4.8 eV work function of single crystal diamond at 108 microns. These results are consistent with a 3-component model in which the work function is controlled by single-crystal (111) diamond at larger grain sizes, graphitic carbon at smaller grain sizes, and by the electron affinity for the intervening grain sizes.
Date: May 2002
Creator: Abbott, Patrick Roland
Partner: UNT Libraries

Landscape forest modeling of the Luquillo Experimental Forest, Puerto Rico.

Description: This thesis contributes to modeling the dynamics of forest community response to environmental gradients and disturbances over a mountain landscape. A gap model (FACET) was parameterized for species of various forest types (Tabonuco, Colorado, Dwarf and Palm), for many terrain conditions and was modified and extended to include species response to excess soil moisture and hurricanes. Landscape cover types were defined by dominance of species of each forest type and canopy height. Parameters of the landscape model (MOSAIC) were calculated from multiple runs of FACET. These runs were determined by combining terrain variables (elevation and soil) and hurricane risk. MOSAIC runs were analyzed for distribution patterns. Geographic Information Systems software was used to process terrain variables, hurricane risk and MOSAIC model output.
Date: December 2002
Creator: Abbott-Wood, Chris
Partner: UNT Libraries

A Study of the Relationship Between the Levels of Self-Awareness within Students Enrolled in Counseling Practicum and the Measurements of Their Counseling Effectiveness

Description: Counselor self-awareness is considered an important aspect of counseling effectiveness according to the American Counseling Association and the American Psychological Association and in numerous studies and articles within the counseling literature. With the effort to improve the effectiveness of counseling practicum students comes the need to understand the relationship between effectiveness ratings and the levels of counselor self-awareness. Gestalt Therapy literature, and the development of the Personal Orientation Inventory (Shostrom, 1963) provided the working definition of self-awareness in this study. Research and evaluation are means for improving the correlation between students' characteristics in counselor training programs and their effectiveness as perceived by faculty and doctoral supervisors. The purpose of this study was to determine the effects of practicum students' ages and their levels of self-awareness upon counseling effectiveness as measured by faculty and doctoral supervisors in a university clinic setting. Twenty-nine students who were enrolled in four practicum classes were administered the Personal Orientation Instrument. Four faculty supervisors and eight doctoral supervisors were administered the Counselor Effectiveness Rating Scale (Myrick & Kelley, 1971). The instruments were administered in the tenth week of the counseling practicum semester. Analyses of the data revealed a statistically significant interaction between the older practicum students' levels of self-awareness and their counselor effectiveness as rated by the more experienced faculty supervisors. Further analyses of the data revealed that there was a statistically significant main effect between the practicum students' age groups and their counselor effectiveness as rated by the less experienced doctoral supervisors.
Date: August 2002
Creator: Abney, Paul C.
Partner: UNT Libraries

Optical Properties and Wave Propagation in Semiconductor-Based Two-Dimensional Photonic Crystals

Description: This work is a theoretical investigation on the physical properties of semiconductor-based two-dimensional photonic crystals, in particular for what concerns systems embedded in planar dielectric waveguides (GaAs/AlGaAs, GaInAsP/InP heterostructures, and self-standing membranes) or based on macro-porous silicon. The photonic-band structure of photonic crystals and photonic-crystal slabs is numerically computed and the associated light-line problem is discussed, which points to the issue of intrinsic out-of-lane diffraction losses for the photonic bands lying above the light line. The photonic states are then classified by the group theory formalism: each mode is related to an irreducible representation of the corresponding small point group. The optical properties are investigated by means of the scattering matrix method, which numerically implements a variable-angle-reflectance experiment; comparison with experiments is also provided. The analysis of surface reflectance proves the existence of selection rules for coupling an external wave to a certain photonic mode. Such rules can be directly derived from symmetry considerations. Lastly, the control of wave propagation in weak-index contrast photonic-crystal slabs is tackled in view of designing building blocks for photonic integrated circuits. The proposed designs are found to comply with the major requirements of low-loss propagation, high and single-mode transmission. These notions are then collected to model a photonic-crystal combiner for an integrated multi-wavelength-source laser.
Date: December 31, 2002
Creator: Agio, Mario
Partner: UNT Libraries Government Documents Department

Transnational Organized Crime and the Drug Business

Description: This study analyzes the activities of the organized crime groups involved in the drug business, as well as examining national and international efforts to control these groups. Specifically, this study addresses the following questions: How is organized crime connected to the international drug business?; What are the major transnational organized crime groups involved in the international drug business?; What is the nature of the drug problem as it relates to organized crime internationally?; What international cooperative law enforcement efforts currently exist to deal with organized crime and the drug business? Findings indicate that efforts to create an effective international law enforcement network are needed to meet the challenges of drug trafficking and globalized crime. To date, such efforts have largely been unsuccessful.
Date: August 2002
Creator: Aksakal, Baris
Partner: UNT Libraries

Use of the Beck Depression Inventory in Northern Brazil

Description: The Beck Depression Inventory (BDI) is a popular screening and research instrument for measuring severity of depression. The instrument was translated to Portuguese for use in Brazil in 1979; however, it was not until recently that its psychometric properties have been tested empirically for the Brazilian population. The purpose of the present study was to explore the BDI's psychometric properties in a northern region of Brazil and to test for possible relationships between certain demographic variables and BDI outcomes. Samples used in this study were from an urban area in Roraima, the northernmost state of Brazil. The BDI showed adequate levels of internal consistency in nonclinical and clinical samples. Female respondents had significantly higher scores than male respondents. Those who had lower levels of education, income, or occupational status had significantly higher scores than those with higher levels of these variables. Adolescents had significantly higher scores than adults from all age groups except those from age 19 to 22. No significant difference was found between those who identified themselves as “indigenous” and those who identified themselves as “non-indigenous.” Regression analysis results showed that the combination of gender, education, and age best accounted for the variance in BDI scores. An ANCOVA revealed that clinically depressed adults had significantly higher BDI scores than nonclinically depressed adults. Factor analysis results showed that there were two main factors in the item structure for both female respondents and male and female respondents combined: one factor of mainly cognitive-affective items and the other factor of mainly somatic items. The results were discussed in terms of the future use of the BDI in Brazil.
Date: May 2002
Creator: Albert, Christopher
Partner: UNT Libraries

The Influence Of Jazz On Timbre In Selected Compositions For Solo Trombone

Description: A significant body of solo literature for the trombone has been written in the last fifty years that draws as much from the jazz tradition as from that of European classical music. While much attention has been paid to these works' use of characteristic jazz rhythms, harmonies and melodic inflections, there has been little focus on timbre, the musical element that perhaps most readily distinguishes jazz from other styles of Western music. This paper focuses on the important role jazz timbres should play in a performer's interpretation of those works that are significantly influenced by jazz. It includes explorations of the significant differences in concepts of timbre between European classical music and jazz, some of the ways in which these timbral differences are produced, and methods by which performers can develop the skills necessary to produce these varied timbres. Particular attention is paid to the importance of timbre to idiomatically appropriate performances of two significant works from the solo trombone repertoire, Robert Suderburg's Night Set (Chamber Music III) and Richard Peaslee's Arrows of Time.
Date: December 2002
Creator: Aldag, Daniel J.
Partner: UNT Libraries

Scalable Computational Chemistry: New Developments and Applications

Description: The computational part of the thesis is the investigation of titanium chloride (II) as a potential catalyst for the bis-silylation reaction of ethylene with hexaclorodisilane at different levels of theory. Bis-silylation is an important reaction for producing bis(silyl) compounds and new C-Si bonds, which can serve as monomers for silicon containing polymers and silicon carbides. Ab initio calculations on the steps involved in a proposed mechanism are presented. This choice of reactants allows them to study this reaction at reliable levels of theory without compromising accuracy. The calculations indicate that this is a highly exothermic barrierless reaction. The TiCl{sub 2} catalyst removes a 50 kcal/mol activation energy barrier required for the reaction without the catalyst. The first step is interaction of TiCl{sub 2} with ethylene to form an intermediate that is 60 kcal/mol below the energy of the reactants. This is the driving force for the entire reaction. Dynamic correlation plays a significant role because RHF calculations indicate that the net barrier for the catalyzed reaction is 50 kcal/mol. They conclude that divalent Ti has the potential to become an important industrial catalyst for silylation reactions. In the programming part of the thesis, parallelization of different quantum chemistry methods is presented. The parallelization of code is becoming important aspects of quantum chemistry code development. Two trends contribute to it: the overall desire to study large chemical systems and the desire to employ highly correlated methods which are usually computationally and memory expensive. In the presented distributed data algorithms computation is parallelized and the largest arrays are evenly distributed among CPUs. First, the parallelization of the Hartree-Fock self-consistent field (SCF) method is considered. SCF method is the most common starting point for more accurate calculations. The Fock build (sub step of SCF) from AO integrals is also often used to avoid ...
Date: December 31, 2002
Creator: Alexeev, Yuri
Partner: UNT Libraries Government Documents Department

Development, Validation, and Evaluation of a Continuous, Real-time, Bivalve Biomonitoring System

Description: A biological monitoring tool to assess water quality using bivalve gape behavior was developed and demonstrated. The purpose of this work was to develop methodologies for screening water quality appropriate to the goals of the watershed paradigm. A model of bivalve gape behavior based on prediction of behavior using autoregressive techniques was the foundation of the bivalve biomonitoring system. Current technology was used in developing the system to provide bivalve gape state data in a continuous real-time manner. A laboratory version of the system, including data collection and analysis hardware and software, was developed for use as a toxicological assay for determination of effective concentrations of toxicant(s) or other types of stress on bivalve gape behavior. Corbicula fluminea was monitored and challenged with copper, zinc, and chlorpyrifos using the system. Effective concentrations of 176±23µg/L copper, 768±412µg/L zinc, and 68µg/L chlorpyrifos were observed using a natural water with high dissolved organic carbon concentrations. A rugged field version of the bivalve biomonitoring system was developed and deployed in two locations. The field systems were fitted with a photovoltaic array, a single board computer, and a CDPD telemetry modem for robust remote operation. Data were telemetered at a time relevant rate of once every ten minutes. One unit was deployed in Lake Lewisville, Denton County, TX in February 2000. Data were telemetered and archived at a 92% success rate. Bivalve gape data demonstrated significant behavioral deviations on average 5 times per month. A second unit was deployed in Pecan Creek, Denton, TX in June 2001. Data from this site were telemetered and archived at a 96% success rate. Over the months of June-August 2001, 16 significant behavioral deviations were observed, 63% of which were correlated with changes in physical/chemical parameters. This work demonstrated the relative sensitivity of bivalve gape as a toxicological endpoint ...
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Date: December 2002
Creator: Allen, H. Joel
Partner: UNT Libraries

Near Threshold electroproduction of the Omega Meson at Momentum Transfer Q2=0.5 (GeV/c)2

Description: Jefferson Lab kaon experiments E91016/E93018 produced data on both strangeness and vector meson electroproduction. The latter part of the experiments was focused on the electroproduction of the omega meson for momentum transfer Q 2 near 0.5 (GeV/c) 2. This reaction was selected from the inelastic ep channel, H-1 (e, e' p)X, by performing involved signal background separation. Tagging the omega meson production only on electron and proton not only introduced appreciable statistical error but also a sizeable systematic uncertainty due to the background removal. Nevertheless, the analysis yielded angular distributions of the differential cross section in the threshold regime extracted with an unprecedented granularity and relatively small errors.
Date: January 1, 2002
Creator: Ambrosewicz, P.
Partner: UNT Libraries Government Documents Department

Integrating life cycle analysis and the ecological footprint calculator to foster sustainable behaviors

Description: Many tools have been developed to assess global, national or regional sustainable development policies. However, as governments develop sustainable policies, individuals must also feel empowered to affect their personal impact on the planet. This thesis integrates three sustainability concepts that lend themselves to individual sustainability: The natural step, life cycle assessment, and the ecological footprint. TNS serves to provide the meaning and substance toward sustainable development. LCA helps provide the framework for assessing sustainability. The EF calculator determines the driving components and measures the qualitative decisions made through TNS and LCA. From the analysis of the household footprint calculator a simplified footprint calculator was developed to assist individuals and communities in setting benchmarks and goals as they move away from over-consumption and towards a sustainable lifestyle.
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Date: December 2002
Creator: Anderle, Kathryn
Partner: UNT Libraries

Development of Novel Polymeric Materials for Gene Therapy and pH-Sensitive Drug Delivery: Modeling, Synthesis, Characterization, and Analysis

Description: The underlying theme of this thesis is the use of polymeric materials in bioapplications. Chapters 2-5 either develop a fundamental understanding of current materials used for bioapplications or establish protocols and procedures used in characterizing and synthesizing novel materials. In chapters 6 and 7 these principles and procedures are applied to the development of materials to be used for gene therapy and drug delivery. Chapter one is an introduction to the ideas that will be necessary to understand the subsequent chapters, as well as a literature review of these topics. Chapter two is a paper that has been published in the ''Journal of Controlled Release'' that examines the mechanism of drug release from a polymer gel, as well as experimental design suggestions for the evaluation of water soluble drug delivery systems. Chapter three is a paper that has been published in the ''Journal of Pharmaceutical Sciences'' that discusses the effect ionic salts have on properties of the polymer systems examined in chapter two. Chapter four is a paper published in the Materials Research Society Fall 2000 Symposium Series dealing with the design and synthesis of a pH-sensitive polymeric drug delivery device. Chapter five is a paper that has been published in the journal ''Biomaterials'' proposing a novel polymer/metal composite for use as a biomaterial in hip arthroplasty surgery. Chapter six is a paper that will appear in an upcoming volume of the Journal ''Biomaterials'' dealing with the synthesis of a novel water soluble cationic polymer with possible applications in non-viral gene therapy. Chapter seven is a paper that has been submitted to ''Macromolecules'' discussing several novel block copolymers based on poly(ethylene glycol) and poly(diethylamino ethyl methacrylate) that possess both pH-sensitive and temperature sensitive properties. Chapter eight contains a summary of the research contained in chapters 2-7 and proposes future research ...
Date: August 27, 2002
Creator: Anderson, Brian Curtis
Partner: UNT Libraries Government Documents Department

An Investigation into the Current Practices of Group Counseling Instructors in the Delivery of the Required Experiential Group in Accredited Institutions

Description: This study was designed to determine the diverse practices of group counseling instructors in the delivery of the required experiential group. A small group experience (experiential group) is required of all counseling students in accredited institutions. The accreditation body for counseling programs is the Council for the Accreditation of Counseling and Related Educational Programs (CACREP). The experiential group has been considered to be a valuable and integral part of counselor training. However, the group has been controversial because of ethical issues involving dual relationships and the right to privacy. The purpose of this study was to determine how group counseling instructors deliver the experiential group, compare current practices to recommended practices in the literature, and recommend changes based on disparities that may exist. The difference between this study and previous surveys of group counseling instructors is that the sample in this study involves CACREP institutions exclusively and the focus is on CACREP standards rather than the standards of the Association for Specialists in Group Work. The results of the study showed that approximately one third of the instructors surveyed indicated that they also serve as leaders of the experiential group. Many of these instructors who serve as group leaders also indicated that they use the group for gatekeeping. Instructors in this study also indicated that understanding group process was the most important goal of the required experiential group. Personal growth was not ranked highly as a goal of the experiential group.
Date: August 2002
Creator: Armstrong, Stephen A.
Partner: UNT Libraries

Understanding Ancient Math Through Kepler: A Few Geometric Ideas from The Harmony of the World

Description: Euclid's geometry is well-known for its theorems concerning triangles and circles. Less popular are the contents of the tenth book, in which geometry is a means to study quantity in general. Commensurability and rational quantities are first principles, and from them are derived at least eight species of irrationals. A recently republished work by Johannes Kepler contains examples using polygons to illustrate these species. In addition, figures having these quantities in their construction form solid shapes (polyhedra) having origins though Platonic philosophy and Archimedean works. Kepler gives two additional polyhedra, and a simple means for constructing the “divine” proportion is given.
Date: August 2002
Creator: Arthur, Christopher
Partner: UNT Libraries

Effector Response of the Aspartate Transcarbamoylase From Wild Type Pseudomonas Putida and a Mutant with 11 Amino Acids Deleted at the N-terminus of PyrB.

Description: Like its enteric counterpart, aspartate transcarbamoylase (ATCase) from Pseudomonas putida is a dodecamer of two different polypeptides. Unlike the enterics, the Pseudomonas ATCase lacks regulatory polypeptides but employs instead inactive dihydroorotases for an active dodecamer. Previous work showed that PyrB contains not only the active site but also the effector binding sites for ATP, UTP and CTP at its N-terminus. In this work, 11 amino acids were deleted from the N-terminus of PyrB and the ATCase with the truncated protein was expressed in E. coli pyrB- and purified. The wild type enzyme was similarly treated. Velocity-substrate plots without effectors gave Michaelis-Menten kinetics in all cases. Deleting 11 amino acids did not affect dodecameric assembly but altered effector responses. When carbamoylphosphate was varied, the mutant enzyme was inhibited by UTP while the wild type enzyme was activated 2-fold. When the aspartate was varied, CTP had no effect on the mutant enzyme but strongly inhibited the wild type enzyme.
Date: May 2002
Creator: AsFour, Hani
Partner: UNT Libraries

Reflections of Revolution: Le Figaro, Le Monde, and Public Opinion in France during the Algerian Conflict (1954-1962)

Description: This thesis is an examination of the printed media in France (1955-1963), as represented by two mainstream newspapers: Le Monde (left-centrist) and Le Figaro (right-centrist). Using these newspapers, as well as Gallup polls recorded at the time, this study explores correlations of what was reported in newspapers and how French public opinion evolved during the course of the war. These two major sources of information are shown to have given contradictory information, thus accounting for some of the paradoxes found in public opinion polls. Specifically, the paradoxes analyzed in the study concern the Front de Libération Nationale (FLN) and the Pieds-Noirs (the European population of North Africa).
Date: December 2002
Creator: Atkins, Michael
Partner: UNT Libraries

Ecology of Chironomids Associated with Myriophyllum Spicatum L. and Heteranthera Dubia Macm

Description: Macroinvertebrate communities inhabiting an exotic, Myriophyllum spicatum, and a native, Heteranthera dubia macrophyte were studied from March 1999 to June 2000 in experimental ponds. Although macrophyte architecture explained some variation in macroinvertebrate abundance between the two macrophytes, most variation was explained by the sampling months. Total number of macroinvertebrates was found to be positively correlated with epiphyton biomass which differed significantly between the two plant types and among sampling months. Taxa richness did not vary between the two plant types. Chironomid larvae were the most abundant organisms and dominated by Apedilum elachistus on both plant communities. Annual production of five chironomid species was estimated by the size-frequency method. Production estimates (P) in g dry wt m-2 yr-1 of plant surface area for the predator Tanypodinae larvae were: Larsia decolarata, P= 0.77 and 0.67, Labrundinia virescens, P= 0.59 and 0.35 on M. spicatum and H. dubia, respectively. Larvae of Cricotopus sylvestris and Psectrocladius vernalis were collected from M. spicatum from March to mid-June. Production of C. sylvestris was found to be 0.46 g dry wt m-2, whereas it was 0.07 g dry wt m-2 for P. vernalis for this period. Apedilum elachistus exhibited the highest productivity: 9.9 g dry wt m-2 yr-1 of plant surface area on M. spicatum, and 8.5 g dry wt m-2 yr-1 on H. dubia. These production estimates are among the highest production values reported for a single species. Additionally, post-ovipositing development times for five chironomid species collected from Myriophyllum and Heteranthera were determined. Three different temperatures (15°, 20° and 25°C) were chosen to rear eggs under 12L: 12D photoperiod. Egg development times ranged between 1-4 days. Larval development times ranged from 44 days at 20°C for Tanypus neopunctipennis to as few as 9 days at 20°C for Larsia decolorata.
Date: May 2002
Creator: Balci, Pinar
Partner: UNT Libraries

Evaluating Radionuclide Air Emission Stack Sampling Systems

Description: The Pacific Northwest National Laboratory (PNNL) operates a number of research and development (R&D) facilities for the U.S. Department of Energy at the Hanford Site, Washington. These facilities are subject to Clean Air Act regulations that require sampling of radionuclide air emissions from some of these facilities. A revision to an American National Standards Institute (ANSI) standard on sampling radioactive air emissions has recently been incorporated into federal and state regulations and a re-evaluation of affected facilities is being performed to determine the impact. The revised standard requires a well-mixed sampling location that must be demonstrated through tests specified in the standard. It also carries a number of maintenance requirements, including inspections and cleaning of the sampling system. Evaluations were performed in 2000 – 2002 on two PNNL facilities to determine the operational and design impacts of the new requirements. The evaluation included inspection and cleaning maintenance activities plus testing to determine if the current sampling locations meet criteria in the revised standard. Results show a wide range of complexity in inspection and cleaning activities depending on accessibility of the system, ease of removal, and potential impact on building operations (need for outages). As expected, these High Efficiency Particulate Air (HEPA)-filtered systems did not show deposition significant enough to cause concerns with blocking of the nozzle or other parts of the system. The tests for sampling system location in the revised standard also varied in complexity depending on accessibility of the sample site and use of a scale model can alleviate many issues. Previous criteria to locate sampling systems at eight duct diameters downstream and two duct diameters upstream of the nearest disturbances is no guarantee of meeting criteria in the revised standard. A computational fluid dynamics model was helpful in understanding flow and contaminant mixing in an exhaust system ...
Date: December 16, 2002
Creator: Ballinger, Marcel Y.
Partner: UNT Libraries Government Documents Department

Computer Supported Collaboration: Is the Transfer of Cognitive Structures Mediated by Mode of Communication?

Description: The objective of this study was to observe evidence of structural transfer among subjects in a group problem-solving activity and determine whether mode of collaborative technology or use of a priming agent affected the nature of transferred structures. Evidence for structural transfer is found in three theoretical perspectives: organizational ditransitive (linguistic) verb structures, adaptive structuration theory, and mental model transfer theory. Dependent variables included various grammatical structures and coefficients derived from pretest and posttest scores on David Kolb's Learning Styles Inventory, modified for the experiment. The combination of changes in grammatical frequencies and learning style may suggest that one or more media or the priming agent may affect structural transfer. Results indicate that groups using the GroupSystems™ collaborative technology produced less overall linguistic content than did subjects using a generic chat system, but employed more complex language as indicated by frequency of the organizational ditransitive verb structure. Also, subjects supplied with an organization chart (priming agent) during the group problem-solving session experienced greater change on the learning styles inventory than did those participating in the session without the chart. These findings suggest that mode of communication and use of priming agents may contribute positively or negatively to the transfer of structures among group members. Researchers, collaborative system designers, organizational leaders, trainers & educators, and frequent collaborative technology system end-users should be aware of these potential affects. Suggestions for future research are provided. Relationship of theoretical foundations of structural transfer to constructivism is discussed.
Date: May 2002
Creator: Bandy, Kenneth E.
Partner: UNT Libraries

Design and Evaluation of System Configurations for an EUV Mask Inspection Microscope

Description: This document is the third sub-report of the EUV AIM design study being conducted at LLNL on behalf of International Sematech (ISMT). The purpose of this study as identified in section 1.2 of the statement of work is to research the basic user requirements of an actinic defect characterization tool, potential design configurations and top-level specifications. The objectives of this design study specifically identified in section 1.3 of the statement of work were to: (1) Determine the user requirements of an actinic defect characterization tool; (2) Determine if an EUV AIM tool is an appropriate platform for actinic defect characterization; (3) Determine possible design configurations and top-level performance specifications; (4) Identify potential technical issues and risks of different technical approaches; (5) Provide estimates of cost relating to different technical approaches; and (6) Provide simulated performance for key subsystems and the entire system. The sub-sections of the study to be addressed were accordingly defined in the statement of work as being: (1) Formulation of top-level specifications; (2) Identification of system configurations suitable for meeting the top-level specifications; (3) Preliminary design of imaging systems; (4) Preliminary design of illumination systems; (5) Prediction and comparison of performance through aerial image calculation; (6) Identification of sub-system requirements; (7) Identification of potential vendors; (8) Estimation of system cost; (9) Identification of technical issues; and (10) Definition of technology transfer or development required. Points 1 and 2 have already been addressed in previous reports to ISMT. This document addresses points 3 to 7, and 9 to 10 of the above list--formulation of a preliminary design of the imaging and illumination systems and the evaluation and comparison of potential designs through aerial image analysis. As such this report should be read in conjunction with and in the context of the previous two reports which separately addressed points ...
Date: August 20, 2002
Creator: Barty, Anton; Taylor, John S.; Hudyma, Russell & Spiller, Eberhard
Partner: UNT Libraries Government Documents Department

Control Mechanisms and Recovery Techniques for Real-Time Data Transmission Over the Internet.

Description: Streaming multimedia content with UDP has become popular over distributed systems such as an Internet. This may encounter many losses due to dropped packets or late arrivals at destination since UDP can only provide best effort delivery. Even UDP doesn't have any self-recovery mechanism from congestion collapse or bursty loss to inform sender of the data to adjust future transmission rate of data like in TCP. So there is a need to incorporate various control schemes like forward error control, interleaving, and congestion control and error concealment into real-time transmission to prevent from effect of losses. Loss can be repaired by retransmission if roundtrip delay is allowed, otherwise error concealment techniques will be used based on the type and amount of loss. This paper implements the interleaving technique with packet spacing of varying interleaver block size for protecting real-time data from loss and its effect during transformation across the Internet. The packets are interleaved and maintain some time gap between two consecutive packets before being transmitted into the Internet. Thus loss of packets can be reduced from congestion and preventing loss of consecutive packets of information when a burst of several packets are lost. Several experiments have been conducted with video data for analysis of proposed model.
Date: August 2002
Creator: Battula, Venkata Krishna Rao
Partner: UNT Libraries

A study of B(s)0 to J/psi phi in the D0 experiment and an example of HEP technology transfer

Description: After years of preparation, data taking with the upgraded D0 detector at the Tevatron proton-antiproton collider has begun. The large amount of data produced in a p{bar p}-collider requires sophisticated triggers to filter out the interesting events. Described in this thesis is the development of trigger software for the newly implemented Silicon Microstrip Tracker. D0 is a multi-purpose detector with a broad physics program. one area being studied at D0 is B mesons. An algorithm for reconstructing the B{sub s}{sup 0} and B{sub d}{sup 0} mesons and for measuring their lifetimes has been developed and is described in this thesis. The results suggest that an improvement of the current lifetime measurements can be achieved within the next two years. The reconstruction of a J/{psi} meson forms the basis for a wide range of b-physics. Data taken with the muon system during the commissioning period of the detector has been analyzed and a signal for the J/{psi} meson has been found. Systematic transfer of HEP technologies into other areas and their commercial exploitation plays an important role in the future of particle physics. An area of particular interest is DNA sequencing as shown by the recent completion of the sequencing of the human genome. The final part of this thesis details the development of a simulation for a high throughput sequencing device which is currently being developed at Imperial College.
Date: January 1, 2002
Creator: Bauer, Daniela Ursula
Partner: UNT Libraries Government Documents Department