Computer Sciences Commons^™

Geometric Integrators For Hamiltonian Pdes, Dmitry Karpeev

Computer Science Theses & Dissertations

We consider methods for systematic construction of algorithms for a class of time-dependent PDEs with Hamiltonian structure. These systems possess phase space geometry and constants of the motion that need to be preserved by the integration algorithm to reflect the qualitative features of the system.

We exploit the structure of Hamiltonian systems, in particular their variational formulation based on a Lagrangian, and the dual covariant formulation, to expose the geometric features of the system that have natural analogs when discretized. We emphasize the local space-time approach to the constructions, making them amenable to parallelization and preconditioning using domain decomposition methods, …

Performance Modeling And Prediction For The Scalable Solution Of Partial Differential Equations On Unstructured Grids, Dinesh Kumar Kaushik

Computer Science Theses & Dissertations

This dissertation studies the sources of poor performance in scientific computing codes based on partial differential equations (PDEs), which typically perform at a computational rate well below other scientific simulations (e.g., those with dense linear algebra or N-body kernels) on modern architectures with deep memory hierarchies. We identify that the primary factors responsible for this relatively poor performance are: insufficient available memory bandwidth, low ratio of work to data size (good algorithmic efficiency), and nonscaling cost of synchronization and gather/scatter operations (for a fixed problem size scaling). This dissertation also illustrates how to reuse the legacy scientific and engineering software …

Object Persistence And Availability In Digital Libraries, Michael L. Nelson, B. Danette Allen

Computer Science Faculty Publications

We have studied object persistence and availability of 1,000 digital library (DL) objects. Twenty World Wide Web accessible DLs were chosen and from each DL, 50 objects were chosen at random. A script checked the availability of each object three times a week for just over 1 year for a total of 161 data samples. During this time span, we found 31 objects (3% of the total) that appear to no longer be available: 24 from PubMed Central, 5 from IDEAS, 1 from CogPrints, and 1 from ETD.

A Scalable Architecture For Harvest-Based Digital Libraries, Xiaoming Liu, Tim Brody, Stevan Harnard, Les Carr, Kurt Maly, Mohammad Zubair, Michael L. Nelson

Computer Science Faculty Publications

This article discusses the requirements of current and emerging applications based on the Open Archives Initiative (OAI) and emphasizes the need for a common infrastructure to support them. Inspired by HTTP proxy, cache, gateway and web service concepts, a design for a scalable and reliable infrastructure that aims at satisfying these requirements is presented. Moreover, it is shown how various applications can exploit the services included in the proposed infrastructure. The article concludes by discussing the current status of several prototype implementations.

Federated Searching Interface Techniques For Heterogeneous Oai Repositories, Xiaoming Liu, Kurt Maly, Mohammad Zubair, Qiaoling Hong, Michael L. Nelson, Frances Knudson, Irma Holtkamp

Computer Science Faculty Publications

Federating repositories by harvesting heterogeneous collections with varying degrees of metadata richness poses a number of challenging issues: (1) how to address the lack of uniform control for various metadata fields in terms of building a rich unified search interface, and (2) how easily new collections and freshly harvested data in existing repositories can be incorporated into the federation supporting a unified interface? This paper focuses on the approaches taken to address these issues in Arc, an Open Archives Initiative compliant federated digital library. At present Arc contains over 1M metadata records from 75 data providers from various subject domains. …

The Single Row Routing Problem Revisited: A Solution Based On Genetic Algorithms, Albert Y. Zomaya, Roger Karpin, Stephan Olariu

Computer Science Faculty Publications

With the advent of VLSI technology, circuits with more than one million transistors have been integrated onto a single chip. As the complexity of ICs grows, the time and money spent on designing the circuits become more important. A large, often dominant, part of the cost and time required to design an IC is consumed in the routing operation. The routing of carriers, such as in IC chips and printed circuit boards, is a classical problem in Computer Aided Design. With the complexity inherent in VLSI circuits, high performance routers are necessary. In this paper, a crucial step in the …

Fast Inner Product Computation On Short Buses, R. Lin, S. Olariu

Computer Science Faculty Publications

We propose a VLSI inner product processor architecture involving broadcasting only over short buses (containing less than 64 switches). The architecture leads to an efficient algorithm for the inner product computation. Specifically, it takes 13 broadcasts, each over less than 64 switches, plus 2 carry-save additions (t_csa) and 2 carry-lookahead additions (t_cla) to compute the inner product of two arrays of N = 2⁹ elements, each consisting of m = 64 bits. Using the same order of VLSI area, our algorithm runs faster than the best known fast inner product algorithm of Smith and Torng …

A Policy-Based Resource Brokering Environment For Computational Grids, Ahmed Hamdan Al-Theneyan

Computer Science Theses & Dissertations

With the advances in networking infrastructure in general, and the Internet in particular, we can build grid environments that allow users to utilize a diverse set of distributed and heterogeneous resources. Since the focus of such environments is the efficient usage of the underlying resources, a critical component is the resource brokering environment that mediates the discovery, access and usage of these resources. With the consumer's constraints, provider's rules, distributed heterogeneous resources and the large number of scheduling choices, the resource brokering environment needs to decide where to place the user's jobs and when to start their execution in a …

Video Indexing And Retrieval Techniques Using Novel Approaches To Video Segmentation, Characterization, And Similarity Matching, Waleed Ezzat Farag

Computer Science Theses & Dissertations

Multimedia applications are rapidly spread at an ever-increasing rate introducing a number of challenging problems at the hands of the research community, The most significant and influential problem, among them, is the effective access to stored data. In spite of the popularity of keyword-based search technique in alphanumeric databases, it is inadequate for use with multimedia data due to their unstructured nature. On the other hand, a number of content-based access techniques have been developed in the context of image indexing and retrieval; meanwhile video retrieval systems start to gain wide attention, This work proposes a number of techniques constituting …

Federating Heterogeneous Digital Libraries By Metadata Harvesting, Xiaoming Liu

Computer Science Theses & Dissertations

This dissertation studies the challenges and issues faced in federating heterogeneous digital libraries (DLs) by metadata harvesting. The objective of federation is to provide high-level services (e.g. transparent search across all DLs) on the collective metadata from different digital libraries. There are two main approaches to federate DLs: distributed searching approach and harvesting approach. As the distributed searching approach replies on executing queries to digital libraries in real time, it has problems with scalability. The difficulty of creating a distributed searching service for a large federation is the motivation behind Open Archives Initiatives Protocols for Metadata Harvesting (OAI-PMH). OAI-PMH supports …

An Object-Oriented Resource Pool Model In Support Of Discrete Event Simulations, Srinivas Gullapalli

Electrical & Computer Engineering Theses & Dissertations

The proper distribution of resources is a key factor in simulation. Resources provide the supporting facilities, equipment, and personnel for carrying out activities. The number of resources has a direct impact on the overall effectiveness of the simulation as it does in real life. If the number is insufficient, it generally takes more time for the process to complete. On the other hand, if the number is too high, the cost incurred on the resources will be unnecessarily large. Therefore, the count should be a compromise between the two extremes.

In this thesis, an attempt is made to generalize the …

Development Of Atlas Based Simulation Capability For Automated Testing, Rami Hanbali

Electrical & Computer Engineering Theses & Dissertations

Computer software is emerging as a powerful tool for controlling a large number of instruments and for the testing of these instruments. The main aim of this work is to provide a software program capable of controlling a large number of engineering instruments at the touch of a button. In addition, the software is to have the capability of connecting the instruments with the desired Unit Under Test. There is great need for such software driven testing in industry, especially for large complex systems. Advantages of such an approach include: (a) automated testing in a very quick and efficient manner; …

Minimum Mean Square Error Spectral Peak Envelope Estimation For Automatic Vowel Classification, Jaishree Venugopal

Electrical & Computer Engineering Theses & Dissertations

Spectral feature computations continue to be a very difficult problem for accurate machine recognition of speech. In this work, which focuses on vowels, a new spectral peak envelope method for vowel classification is developed, based on a missing frequency components model of speech recognition. According to the missing frequency components model, vowel recognition depends only on the spectral (harmonic) peaks. Smoothing and interpolation of the spectra, performed in the standard cepstral analysis method commonly used in automatic speech recognition, actually loses valuable information and results in reduced recognition accuracy. The new method for feature extraction presented in this thesis is …

A Software Reliability Model Combining Representative And Directed Testing, Brian Michael Mitchell

Computer Science Theses & Dissertations

Traditionally, software reliability models have required that failure data be gathered using only representative testing methods. Over time, however, representative testing becomes inherently less effective as a means of improving the actual quality of the software under test. Additionally, the use of failure data based on observations made during representative testing has been criticized because of the statistical noise inherent in this type of data. In this dissertation, a testing method is proposed to make reliability testing more efficient and accurate. Representative testing is used early, when the rate of fault revelation is high. Directed testing is used later in …

A Model To Evaluate The Effect Of Organizational Adaptation, Holly A. H. Handley, Alexander H. Levis

Engineering Management & Systems Engineering Faculty Publications

When an organization’s output declines due to either internal changes or changes in its external environment, it needs to adapt. In order to evaluate the effectiveness of different adaptation strategies on organizational per- formance, an organizational model composed of individual models of a five stage interacting decision maker was designed using an object oriented design approach and implemented as a Colored Petri net. The concept of entropy is used to calculate the total activity value, a surrogate for decision maker workload, based on the functional partition and the adaptation strategy being implemented. The individual decision maker’s total activity is monitored, …

Perceptual Cues And Subjective Organization In A Virtual Information Workspace, Todd M. Eischeid

Psychology Theses & Dissertations

The key to effectively using the immense body of data on the Internet is an efficient method of organizing relevant information. Researchers and designers are beginning to promote the advantages of three-dimensional (3D) models of information storage and retrieval; however, the potential benefits of perceptual depth cues have not been systematically studied.

The present study used a computer task to examine the effectiveness of three types of virtual desktops. A two-dimensional (2D) virtual desktop display, lacking in the cues that give the illusion of depth, was compared to two different 3D virtual desktops, both of which used perceptual cues to …

New Sequential And Scalable Parallel Algorithms For Incomplete Factor Preconditioning, David A. Hysom

Computer Science Theses & Dissertations

The solution of large, sparse, linear systems of equations Ax = b is an important kernel, and the dominant term with regard to execution time, in many applications in scientific computing. The large size of the systems of equations being solved currently (millions of unknowns and equations) requires iterative solvers on parallel computers. Preconditioning, which is the process of translating a linear system into a related system that is easier to solve, is widely used to reduce solution time and is sometimes required to ensure convergence. Level-based preconditioning (ILU(ℓ)) has long been used in serial contexts and is widely recognized …

Entropy Generation Method To Quantify Thermal Comfort, S. C. Boregowda, S. N. Tiwari, S. K. Chaturvedi

Mechanical & Aerospace Engineering Faculty Publications

The present paper presents a thermodynamic approach to assess the quality of human-thermal environment interaction and quantify thermal comfort. The approach involves development of entropy generation term by applying second law of thermodynamics to the combined human-environment system. The entropy generation term combines both human thermal physiological responses and thermal environmental variables to provide an objective measure of thermal comfort. The original concepts and definitions form the basis for establishing the mathematical relationship between thermal comfort and entropy generation term. As a result of logic and deterministic approach, an Objective Thermal Comfort Index (OTCI) is defined and established as a …

Arc - An Oai Service Provider For Digital Library Federation, Xiaoming Liu, Kurt Maly, Mohammad Zubair, Michael L. Nelson

Computer Science Faculty Publications

The usefulness of the many on-line journals and scientific digital libraries that exist today is limited by the inability to federate these resources through a unified interface. The Open Archive Initiative (OAI) is one major effort to address technical interoperability among distributed archives. The objective of OAI is to develop a framework to facilitate the discovery of content in distributed archives. In this paper, we describe our experience and lessons learned in building Arc, the first federated searching service based on the OAI protocol. Arc harvests metadata from several OAI compliant archives, normalizes them, and stores them in a search …

Smart Objects And Open Archives, Michael L. Nelson, Kurt Maly

Computer Science Faculty Publications

Within the context of digital libraries (DLs), we are making information objects "first-class citizens". We decouple information objects from the systems used for their storage and retrieval, allowing the technology for both DLs and information content to progress independently. We believe dismantling the stovepipe of "DL-archive-content" is the first step in building richer DL experiences for users and insuring the long-term survivability of digital information. To demonstrate this partitioning between DLs, archives and information content, we introduce "buckets": aggregative, intelligent, object-oriented constructs for publishing in digital libraries. Buckets exist within the "Smart Object, Dumb Archive" (SODA) DL model, which promotes …

Buckets: Smart Objects For Digital Libraries, Michael L. Nelson

Computer Science Faculty Publications

Current discussion of digital libraries (DLs) is often dominated by the merits of the respective storage, search and retrieval functionality of archives, repositories, search engines, search interfaces and database systems. While these technologies are necessary for information management, the information content is more important than the systems used for its storage and retrieval. Digital information should have the same long-term survivability prospects as traditional hardcopy information and should be protected to the extent possible from evolving search engine technologies and vendor vagaries in database management systems. Information content and information retrieval systems should progress on independent paths and make limited …

Efficient Algorithms For Graphs With Few P-4’S, Luitpold Babel, Ton Kloks, Jan Kratochvíl, Dieter Kratsch, Kaiko Müller, Stephan Olariu

Computer Science Faculty Publications

We show that a large variety of NP-complete problems can be solved efficiently for graphs with 'few' P₄'s. We consider domination problems (domination, total domination, independent domination. connected domination and dominating clique), the Steiner tree problem, the vertex ranking problem, the pathwidth problem, the path cover number problem, the hamiltonian circuit problem, the list coloring problem and the precoloring extension problem. We show that all these problems can be solved in linear time for the class of (q,q - 4)-graphs, for every fixed q. These are graphs for which no set of at most q. vertices induces more …

External Memory Algorithms For Factoring Sparse Matrices, Florin Dobrian

Computer Science Theses & Dissertations

We consider the factorization of sparse symmetric matrices in the context of a two-layer storage system: disk/core. When the core is sufficiently large the factorization can be performed in-core. In this case we must read the input, compute, and write the output, in this sequence. On the other hand, when the core is not large enough, the factorization becomes out-of-core, which means that data movement and computation must be interleaved.

We identify two major out-of-core factorization scenarios: read-once/write-once (R1/W1) and read-many/write-many (RM/WM). The former requires minimum traffic, exactly as much as the in-core factorization: reading the input and writing the …

Studies Related To The Design And Implementation Of A Magnetic Suspension And Balance System, Syed Adeel Akhtar Jafri

Electrical & Computer Engineering Theses & Dissertations

This thesis presents studies related to the magnetic suspension and balance system (MSBS) of the Princeton/ONR High Reynolds Number Testing Facility (HRTF). The main motivation for developing the MSBS is to provide interference free aero/hydrodynamic testing of submersible models, which will lead to more accurate measurements. From the controls point of view, the main specification of the MSBS is to robustly control the position of a submersible model in five degrees of freedom (DOF), including three translational as well as pitching and yawing positions. The MSBS should not only regulate the submersible model's position but should also allow for small …

Buckets: Smart Objects For Digital Libraries, Michael L. Nelson

Computer Science Theses & Dissertations

Discussion of digital libraries (DLs) is often dominated by the merits of various archives, repositories, search engines, search interfaces and database systems. While these technologies are necessary for information management, information content and information retrieval systems should progress on independent paths and each should make limited assumptions about the status or capabilities of the other. Information content is more important than the systems used for its storage and retrieval. Digital information should have the same long-term survivability prospects as traditional hardcopy information and should not be impacted by evolving search engine technologies or vendor vagaries in database management systems.

Digital …

Routing Optimization Through Computer-Aided Simulation, Madhusudhan Akundi

Electrical & Computer Engineering Theses & Dissertations

Routing has always been a challenging field, and the various techniques of mathematics and operations research have been developed. For commercial organizations, routing has begun to receive extensive attention because of the savings gained in terms of time, money, personnel, and the transportation fleet by developing optimized routing networks. Until recently, it was difficult to develop optimized networks due to the computational difficulties of the problem. However, with the advancement in computer technology and processing speeds, it has become possible to simulate a large number of routing scenarios and determine optimal solutions for a given set of constraints. Not only …

Design Of Adaptive Sliding Mode Fuzzy Control For Robot Manipulator Based On Extended Kalman Filter, Abdelrahman Aledhaibi

Mechanical & Aerospace Engineering Theses & Dissertations

In this work, a new adaptive motion control scheme for robust performance control of robot manipulators is presented. The proposed scheme is designed by combining the fuzzy logic control with the sliding mode control based on extended Kalman filter. Fuzzy logic controllers have been used successfully in many applications and were shown to be superior to the classical controllers for some nonlinear systems. Sliding mode control is a powerful approach for controlling nonlinear and uncertain systems. It is a robust control method and can be applied in the presence of model uncertainties and parameter disturbances, provided that the bounds of …

A Flowchart Structure For Modification Of A Modsim Process Model, Murali K. Adatrao

Electrical & Computer Engineering Theses & Dissertations

There are many software processes and software development models that support the development of a software model prior to implementation. However, more often than not, these practices are not followed resulting in a lack of documentation of the intended functionality of the software. As a result, software often becomes a black box for later developers. Even a simple bug fix can turn into an exhaustive task for the developers, as they must attempt to infer the intended system behavior. New designers cannot make any changes to the software or extend the software behavior, as the underlying model within the software …

Improving Co-Generation Plant Performance Using Computer Modeling Software: A Parametric Study, Gerald R. Munyan

Mechanical & Aerospace Engineering Theses & Dissertations

The desire to optimize plant performance continues to direct the goals of design and plant engineers associated with larger thermal systems. With the increasing availability of software designed for modeling thermal systems, the task of improving plant performance continues to develop. The ability to model a facility using a commercially available software package allows the design engineer and plant engineer to investigate the effects of variations in plant conditions or components on overall plant operations.

An analysis of the Kirk Lumber Company's co-generating facility was performed using the modeling program PROSIM written by the consulting engineering firm Endat Oy, of …

An Object-Oriented Algorithmic Laboratory For Ordering Sparse Matrices, Gary Karl Kumfert

Computer Science Theses & Dissertations

We focus on two known NP-hard problems that have applications in sparse matrix computations: the envelope/wavefront reduction problem and the fill reduction problem. Envelope/wavefront reducing orderings have a wide range of applications including profile and frontal solvers, incomplete factorization preconditioning, graph reordering for cache performance, gene sequencing, and spatial databases. Fill reducing orderings are generally limited to—but an inextricable part of—sparse matrix factorization.

Our major contribution to this field is the design of new and improved heuristics for these NP-hard problems and their efficient implementation in a robust, cross-platform, object-oriented software package. In this body of research, we (1) examine …