Physical Sciences and Mathematics Commons^™

Heterogeneous Radial Basis Function Networks, Tony R. Martinez, D. Randall Wilson

Faculty Publications

Radial Basis Function (RBF) networks typically use a distance function designed for numeric attributes, such as Euclidean or city-block distance. This paper presents a heterogeneous distance function which is appropriate for applications with symbolic attributes, numeric attributes, or both. Empirical results on 30 data sets indicate that the heterogeneous distance metric yields significantly improved generalization accuracy over Euclidean distance in most cases involving symbolic attributes.

Performance Study Of A Brazilian Air Force Data Communications Network, Oswaldo Zanelli

Theses and Dissertations

This thesis consists of a performance analysis of two network models using different protocols, the X.25 and Asynchronous Transfer Mode (ATM). X.25 is currently used in the data communications network infrastructure in the Brazilian Air Force. ATM is a high speed network technology. Simulations of both models were performed to compare the two technologies. This study examines the traffic load that each network can handle while still providing a good quality of service (QoS). The X.25 network model proved to have a sufficient capacity to handle the projected workload, but it presented a low QoS when a more intense traffic …

Electrical Characterization Of Gasb Based Semiconductors For 2-4 Micrometers Diode Laser Applications, Daniel K. Johnstone

Theses and Dissertations

Deep Level Transient Spectroscopy (DLTS) was used to characterize the band offsets and deep levels in MBE grown GaSb-based semiconductors that are used in 2-4 µm laser diode structures. One of several deep level traps found in Al_xGa_1-xAs_ySb_1-y (x=0, 0.5, 0.6, 1.0) is a GaSb double acceptor trap. Progress is also made in establishing the model for the DX center in this material. The degree of compensation of the donor related DX center by GaSb affect where donors are situated, giving preference to one configuration over the many other possible configurations. One minority …

Influence Of Rice Production On The Quality Of Water In Tailwater Collection Reservoirs, R. A. Dewell, T. L. Lavy

Technical Reports

Since maintaining high water quality standards in the state remains a high priority, monitoring for pesticides in water sources must continue. Determining the type, concentration, and characteristics of any pesticides present in water supplies are essential to the overall assessment of water quality. Five independent locations, implementing contained water management systems and recyclable water, were monitored in 1995 and 1996. Irrigation, runoff, and pond water samples were collected every 10 to 14 days between permanent flood establishment and draining. Water samples were transported to the laboratory and extracted for 16 pesticides using solid phase extraction (SPE) techniques. Quantification and confirmation …

Static-Electric-Field Effects On High Harmonic Generation, Min-Qi Bao, Anthony F. Starace

Anthony F. Starace Publications

High harmonic generation in the presence of a static electric field is analyzed theoretically by an extension of the zero-range potential model treatment of Becker et al [Phys. Rev. A 50, 1540 (1994)]. For H- and a CO₂ laser of 5 × 10¹⁰ W/cm² intensity, a static electric field of 100 kV/cm is shown to produce a plateau from the 3rd to the 23rd harmonic in which neighboring even and odd harmonics are of comparable intensity. Furthermore, odd harmonics on the plateau are one or more orders of magnitude more intense than in the absence of the …

An Investigation On Nonenzymatic Autoxidation Of Phenolic Compounds In Natural Waters, Lei Jiang

Masters Theses

The nonenzymatic autoxidation of the phenolic compounds chlorogenic acid in aqueous solution was studied. The study demonstrated that the oxidation rate of chlorogenic acid was strongly dependent on pH. The higher the pH, the faster the rate of oxidation. The involvement of phenolate ions and radicals in oxidation reactions are two possible reasons for the pH dependency. The presence of a trace amounts of reducible transition metal ions, such as copper(II), dramatically increases the oxidation rate of chlorogenic acid. Light also increases the oxidation rate of chlorogenic acid. However, the photochemical reaction was a much slower process.

The TLC and …

Elimination Of All-Optical Cycles In Wavelength-Routed Optical Networks, Jason Iness, Byrav Ramamurthy, Biswanath Mukherjee, Krishna Bala

School of Computing: Faculty Publications

A transparent (wide-area) wavelength-routed optical network may be constructed by using wavelength cross-connect switches connected together by fiber to form an arbitrary mesh structure. The network is accessed through electronic stations that are attached to some of these cross-connects. These wavelength cross-connect switches have the property that they may configure themselves into unspecified states. Each input port of a switch is always connected to some output port of the switch whether or not such a connection is required for the purpose of information transfer. Due to the presence of these unspecified states, there exists the possibility of setting up unintended …

Is The Universe Expanding?: An Historical And Philosophical Perspective For Cosmologists Starting Anew, David A. Vlosak

Masters Theses

This study addresses the problem of how scientists ought to go about resolving the current crisis in big bang cosmology. Although this problem can be addressed by scientists themselves at the level of their own practice, this study addresses it at the meta-level by using the resources offered by philosophy of science.

There are two ways to resolve the current crisis. Either cosmologists can continue working on big bang theory or they can start anew. For those who choose to start anew, this study argues it would be a mistake for them to assume any new cosmological theory would have …

Random Cayley Maps, Michelle Schultz

Dissertations

Determining the orientable surfaces on which a given graph can be imbedded is the central problem of topological graph theory. The natural setting for studying this problem is random topological graph theory, where a probability model is defined on the space of all labeled 2-cell imbeddings of a connected graph. The major focus of this dissertation is the study of Cayley maps in the setting of random topological graph theory.

A Cayley graph provides a representation of a finite group and a fixed generating set for the group. A Cayley map is an imbedding of a Cayley graph whose vertex …

Ionization And Charge Changing In 0.5 - 8 Qmev Li^Q+ + He (Q=1,2,3) Collisions And Setup Of An Electron Spectrometer Control System, Oliver Woitke

Dissertations

Projectile charge changing and target ionization cross sections are measured for 0.5 to 8 qMeV Li^q+ + He (q=1,2,3) collisions. Total cross sections for single-electron capture (for L i^1,2,3+) and single-electron loss (for L i^1,2+) are obtained and compared to existing experimental and theoretical data. Also, single and double target ionization of He associated with specific outgoing projectile charge states are identified using coincidence techniques. Cross sections for target ionization associated with no projectile charge change (direct ionization), single-electron capture, and single-electron loss are measured and compared to existing experimental data and to available calculations. Double-to-single target ionization ratios R …

Specifying Object-Oriented Federated Database From Existing Databases, Ee Peng Lim, M. L. Lim, J. Srivastava

Research Collection School Of Computing and Information Systems

In this paper, we present a mapping strategy that is based on a proposed set of DB integration operations. We first define an OO federated DB as a virtual view on multiple OO export DBs. Our DB mapping strategy systematically derives each of the class extents, deep class extents and relationships of the federated DB using an operator tree consisting of the integration operations. This mapping approach differs from the other existing approaches in that it is algebraic based, and is therefore very suitable for implementing federated query processing.

On The Use Of The Complexity Index As A Measure Of Complexity In Activity Networks, Bert De Reyck, Willy Herroelen

Research Collection Lee Kong Chian School Of Business

A large number of optimal and suboptimal procedures have been developed for solving combinatorial problems modeled as activity networks. The need to differentiate between easy and hard problem instances and the interest in isolating the fundamental factors that determine the computing effort required by these procedures, inspired a number of researchers to develop various complexity measures. In this paper we investigate the relation between the hardness of a problem instance and the topological structure of its underlying network, as measured by the complexity index. We demonstrate through a series of experiments that the complexity index, defined as the minimum number …

Advances In Wetland Status And Trends Monitoring Cumulative Error Comparisons, Stacie A.C. Nelson, Virginia Institute Of Marine Science, Wetlands Program

Reports

No abstract provided.

Towards Designing A Knowledge-Based Tutoring System : Sql-Tutor As An Example, Gang Zhou

Dissertations

A Knowledge-Based Tutoring System, also sometimes called an Intelligent Tutoring System, is a computer based instructional system that uses artificial intelligence techniques to help people learn some subject. The goal of the system is to provide private tutoring to its students based on their different backgrounds, requests, and interests. The system knows what subject materials it should teach, when and how to teach them, and can diagnose the mistakes made by the students and help them correct the mistakes.

The major objective of this dissertation is to investigate and develop a generic framework upon which we can build a Knowledge-Based …

Pattern Discovery In Sequence Databases : Algorithms And Applications To Dna/Protein Classification, Gung-Wei Chirn

Dissertations

Sequence databases comprise sequence data, which are linear structural descriptions of many natural entities. Approximate pattern discovery in a sequence database can lead to important conclusions or prediction of new phenomena. Traditional database technology is not suitable for accomplishing the task, and new techniques need to be developed.

In this dissertation, we propose several new techniques for discovering patterns in sequence databases. Our techniques incorporate pattern matching algorithms and novel heuristics for discovery and optimization. Experimental results of applying the techniques to both generated data and DNA/proteins show the effectiveness of the proposed techniques.

We then develop several classifiers using …

Knowledge Discovering For Document Classification Using Tree Matching In Texpros, Ching-Song Wei

Dissertations

This dissertation describes a knowledge-based system for classifying documents based upon the layout structure and conceptual information extracted from the content of the document. The spatial elements in a document are laid out in rectangular blocks which are represented by nodes in an ordered labelled tree, called the "layout structure tree" (L-S Tree). Each leaf node of a L-S Tree points to its corresponding block content. A knowledge Acquisition Tool (KAT) is devised to create a Document Sample Tree from L-S Tree, in which each of its leaves contains a node content conceptually describing its corresponding block content. Then, applying …

Integrating Hypertext With Information Systems Through Dynamic Mapping, Jiangling Wan

Dissertations

This dissertation presents a general hypertext model (GHMI) supporting integration of hypertext and information systems through dynamic mapping. Information systems integrated based on this model benefit from hypertext function-alities (such as linking, backtracking, history, guided tours, annotations, etc.) while preserving their own computation capabilities. Although systems supporting integration of hypertext and interface-oriented information systems do exist in hypertext literature, there is no existing model or system effectively supporting integration of hypertext and computation-oriented information systems. GHMI makes its major contributions by both extending and specifying the well-known Dexter Hypertext Reference Model. GHMI extends the Dexter model to overcome its limitations. …

Theory And Design Of Portable Parallel Programs For Heterogeneous Computing Systems And Networks, Ying-Chieh Wu

Dissertations

A recurring problem with high-performance computing is that advanced architectures generally achieve only a small fraction of their peak performance on many portions of real applications sets. The Amdahl's law corollary of this is that such architectures often spend most of their time on tasks (codes/algorithms and the data sets upon which they operate) for which they are unsuited. Heterogeneous Computing (HC) is needed in the mid 90's and beyond due to ever increasing super-speed requirements and the number of projects with these requirements. HC is defined as a special form of parallel and distributed computing that performs computations using …

Continuous Monitoring Of Volatile Organic Compounds Using Microtrap Based Gas Chromatographic Systems, Yonghua Xu

Dissertations

Continuous analysis allows a representative portion of a sample to flow continuously through an analytical instrument, which gives analytical information with little or no delay in time. A microtrap is a small diameter tube packed with adsorbents in series. When a gaseous sample containing volatile organic compounds (VOCs) flows through the microtrap, the VOCs can be trapped selectively by adsorbents. Then a pulse of electrical current is applied to the microtrap. This rapid heating results in a desorption that can act as a sharp injection for GC separation. Thus the microtrapped sample is the total amount of VOC present in …

Smith On Krauss, 'The Physics Of Star Trek', Anne Collins Smith

Faculty Publications

Review of Lawrence M. Krauss.The Physics of Star Trek. New York: Basic Books, 1995. xvi + 188 pp. $20.00(cloth), ISBN 978-0-465-00559-8.

Reviewed by Anne Collins Smith (Austin Community College) Published on H-PCAACA (May, 1996)

Stratospheric Ozone Layer Depletion : A Computer Aided Case Study, James M. Lipuma

Theses

In industries today, there is a desire to stop pollution before it starts, through the process of pollution prevention. Unfortunately, many university level students are not exposed to the thinking process involved in environmental problem solving early enough in their academic career, if they are exposed to it at all. The goal of this thesis is to develop and to evaluate an interdisciplinary case-study about the depletion of the stratospheric ozone layer by chlorofluorocarbons (CFCs). This case-study will be used to teach first year chemistry students about environmental problem solving. The case study was assembled from existing literature according to …

Degradation And Breakdown In Ultra-Thin Silicon Oxides, Christopher Franck

Theses

Emerging trends in the semiconductor device industry call for detailed knowledge of the properties of devices whose dimensions are small enough to exploit Quantum Mechanical effects. This thesis presents a complete picture of oxide degradation in MOS direct tunnel diodes (t0 <3.4 nm). It is demonstrated that for structures fabricated at different facilities and stressed with either gate or substrate injection, a universal degradation mode is revealed which is manifested as the build up of positive charge in the oxide. The data gathered demonstrates that the positive charging phenomena in sub-3.5 nm oxides is independent of oxide thickness, and is characterized by a voltage threshold and two-regime temperature dependence. Further, the catastrophic failure, or breakdown, of these oxides was studied and the strongest evidence to date is presented which links the positive charging phenomena to the oxide breakdown. This thesis concludes with the presentation of a novel device design which can exploit the properties of degradation and breakdown, in thin oxides, to achieve an EEPROM memory cell of superior endurance.

Speciation And Determination Of Trace Lead : Methodology Development And Analysis Of Natural Waters Using Chelex-100 And Gfaas, Xidan Ma

Theses

The development of a method for speciation, preconcentration, and determination of lead was successfully conducted using Chelex-100 and graphite furnace atomic absorption spectroscopy (GFAAS). Sorption under static conditions and direct measurements in the bead slurry or after fast elution of lead from beads with HNO3 solution was used. The effects of buffers, sorption kinetics, filtration criteria, sample concentration, resin particle size and temperature program for the GFAAS were carefully studied. In this study, synthetic aqueous samples containing lead were preconcentrated under static conditions using the ion exchange resin, Chelex-100, and the resin was directly analyzed using GFAAS. The batch preconcentration …

Pollution Prevention In The New Jersey Chemical Industry : Motivations And Barriers To Commitment, Judith A. Thornton

Theses

This study of the New Jersey Chemical Industry identifies the primary elements that lead to or inhibit company commitments to pollution prevention. A direct measure of facility pollution prevention commitment is developed that takes into account: organizational support attributes, past reductions achievements, current methods implementation, process reduction goals, and special environmental initiatives. The "P2 Commitment Index" allows for categorization of facilities so that the needs and interests of varying groups may be differentiated.

Higher level commitments are associated with: establishment of company pollution prevention policy, setting of prioritized facility goals, and measurement and reporting on pollution prevention progress. Facilities at …

The Reactions Of Nox With Diesel Soot Over Cu-Zsm-5 Catalyst, Shu Sun

Theses

Air pollution from the exhaust of Diesel engines consisting of relatively high concentrations of NO_x and particulates is a difficult problem to overcome because no fully effective technology to control these emission is available. The existing methods to reduce NO_x and soot can not satisfy the provisions of the 1990 CAAA (Clean Air Act Amendment). Cu-ZSM-5, a catalyst in which Cu has been ion-exchanged with H+, can catalyze the decomposition of NO to N₂ and O₂ and reduction to N₂ and O₂ with light hydrocarbons such as propene or Diesel soot in the presence …

Oxidation Of Isobutane And Isobutene Reaction Pathways And Detailed Mechanism, Chiung-Ju Chen

Theses

A reaction mechanism consisting of 248 elementary reactions and 138 species has been developed to model experimental systems - decomposition of 2,2,3,3 tetramethylbutane in the presence of oxygen and oxidation of isobutene. This elementary reaction mechanism based on two important reaction systems: tert-butyl radical with O₂ and allylic isobutenyl radical with O₂, plus their subsystems, such as isobutene + HO₂, isobutene + OH and allylic isobuteny1hydroxy + O₂. Thermochernical kinetic parameters are developed for each elementary reaction and a chemical activation kinetic analysis using quantum RiceRamsperger-Kassel (QRRK) theory for k(E) and modified strong …

Design And Fabrication Of A Miniature Pressure Sensor Head Using Direct Bonded Ultra-Thin Silicon Wafers, Chad Eugene Statler

Theses

A miniature pressure sensor head is designed and fabricated using an ultra-thin silicon membrane directly bonded to an excimer laser micromachined substrate. The pressure sensor head has its intended implementation as part of an optically interrogated device with sensitivity to pressures ranging from 0.5 to 4.0 MPa. The pressure range design is shown to be easily adjusted by tailoring the thickness of the membrane wafer. The fabrication process features numerous advantages over existing pressure sensor construction technology including a maskless procedure and no chemical etching or mechanical thinning necessary to form the membrane after bonding. An optic lever is constructed …

Segmenting Workstation Screen Images, Denis M. Serenyi

Dartmouth College Undergraduate Theses

No abstract provided.

Supermassive Binaries And Extragalactic Jets, C. Martin Gaskell

Department of Physics and Astronomy: Faculty Publications

Some quasars show Doppler shifted broad emission line peaks. I give new statistics of the occurrence of these peaks and show that, while the most spectacular cases are in quasars with strong jets inclined to the line of sight, they are also almost as common in radio-quiet quasars. Theories of the origin of the peaks are reviewed and it is argued that the displaced peaks are most likely produced by supermassive binaries. 3C 390.3 shows precisely the change in radial velocity predicted by the supermassive binary model. The separations of the peaks in 3C 390.3-type objects are consistent with orientation-dependent …

Twin Ice Cores From Greenland Reveal History Of Climate Change, More, R. Alley, Paul Andrew Mayewski, D. Peel, B. Stauffer

Earth Science Faculty Scholarship

Two projects conducted from 1989 to 1993 collected parallel ice cores—just 30 km apart— from the central part of the Greenland ice sheet. Each core is more than 3 km deep and extends back 110,000 years. In short, the ice cores tell a clear story: humans came of age agriculturally and industrially during the most stable climatic regime recorded in the cores. Change—large, rapid, and global—is more characteristic of the Earth's climate than is stasis.