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Articles 1291 - 1320 of 1334

Full-Text Articles in Computer Engineering

Bidirectional Lao* Algorithm (A Faster Approach To Solve Goal-Directed Mdps), Venkata Deepti Kiran Bhuma Jan 2004

Bidirectional Lao* Algorithm (A Faster Approach To Solve Goal-Directed Mdps), Venkata Deepti Kiran Bhuma

University of Kentucky Master's Theses

Uncertainty is a feature of many AI applications. While there are polynomial-time algorithms for planning in stochastic systems, planning is still slow, in part because most algorithms plan for all eventualities. Algorithms such as LAO* are able to find good or optimal policies more quickly when the starting state of the system is known.

In this thesis we present an extension to LAO*, called BLAO*. BLAO* is an extension of the LAO* algorithm to a bidirectional search. We show that BLAO* finds optimal or E-optimal solutions for goal-directed MDPs without necessarily evaluating the entire state space. BLAO* …


Infrastructure For Performance Tuning Mpi Applications, Kathryn Marie Mohror Jan 2004

Infrastructure For Performance Tuning Mpi Applications, Kathryn Marie Mohror

Dissertations and Theses

Clusters of workstations are becoming increasingly popular as a low-budget alternative for supercomputing power. In these systems,message-passing is often used to allow the separate nodes to act as a single computing machine. Programmers of such systems face a daunting challenge in understanding the performance bottlenecks of their applications. This is largely due to the vast amount of performance data that is collected, and the time and expertise necessary to use traditional parallel performance tools to analyze that data.

The goal of this project is to increase the level of performance tool support for message-passing application programmers on clusters of workstations. …


Pperfgrid: A Grid Services-Based Tool For The Exchange Of Heterogeneous Parallel Performance Data, John Jared Hoffman Jan 2004

Pperfgrid: A Grid Services-Based Tool For The Exchange Of Heterogeneous Parallel Performance Data, John Jared Hoffman

Dissertations and Theses

This thesis details the approach taken in developing PPerfGrid. Section 2 discusses other research related to this project. Section 3 provides general background on the technologies utilized in PPerfGrid, focusing on the components that make up the Grid services architecture. Section 4 provides a description of the architecture of PPerfGrid. Section 5 details the implementation of PPerfGrid. Section 6 presents tests designed to measure the overhead and scalability of the PPerfGrid application. Section 7 suggests future work, and Section 8 concludes the thesis.


A Book Management System Elibrary, Shanpeng Song Jan 2004

A Book Management System Elibrary, Shanpeng Song

Theses Digitization Project

"eLibrary" is a book management software application that runs on Microsoft Windows platforms. The software incorporates a Windows Explorer like interface and XML/XSL to display book details. The purpose of this project is to build a full-featured, commerical-quality software package to help people manage their books (either printed or electronic). The goal is for eLibrary to be a complete solution for people who wish to build their own personal electronic library catalog.


Creating A Video Device Application, Kevin Septor Jan 2004

Creating A Video Device Application, Kevin Septor

Honors Theses

A video device, such as a webcam, has the capability to be used in many ways, including recording video and behaving like a security camera. A TV tuner card can also record video, and in addition be used for watching television. However, the video hardware and device driver the operating system uses to access it are only capable of delivering raw frames of video. A user space application is necessary for exploiting the capabilities of such a device beyond reading sequential frames of video. This research explores the desiderata in a powerful video device application, and introduces a program that …


Adl Modeling Of Jini-Upnp Bridging Using Rapide, Rehab Ahmed El Kharboutly Feb 2003

Adl Modeling Of Jini-Upnp Bridging Using Rapide, Rehab Ahmed El Kharboutly

Archived Theses and Dissertations

No abstract provided.


Entertainics, Jesus Mario Torres Garza Jan 2003

Entertainics, Jesus Mario Torres Garza

Theses Digitization Project

Entertainics is a web-based software application used to gather information about DVD players from several web-sites on the internet. The purpose of this software is to help users search for DVD players in a faster and easier way, by avoiding the navigation on every web-site that contains this product.


A Performance Study Of Lam And Mpich On An Smp Cluster, Brian Patrick Kearns Dec 2002

A Performance Study Of Lam And Mpich On An Smp Cluster, Brian Patrick Kearns

Dissertations and Theses

Many universities and research laboratories have developed low cost clusters, built from Commodity-Off-The-Shelf (COTS) components and running mostly free software. Research has shown that these types of systems are well-equipped to handle many problems requiring parallel processing. The primary components of clusters are hardware, networking, and system software. An important system software consideration for clusters is the choice of the message passing library.

MPI (Message Passing Interface) has arguably become the most widely used message passing library on clusters and other parallel architectures, due in part to its existence as a standard. As a standard, MPI is open for anyone …


Content Aware Request Distribution For High Performance Web Service: A Performance Study, Robert M. Jones Jul 2002

Content Aware Request Distribution For High Performance Web Service: A Performance Study, Robert M. Jones

Dissertations and Theses

The World Wide Web is becoming a basic infrastructure for a variety of services, and the increases in audience size and client network bandwidth create service demands that are outpacing server capacity. Web clusters are one solution to this need for high performance, highly available web server systems. We are interested in load distribution techniques, specifically Layer-7 algorithms that are content-aware. Layer-7 algorithms allow distribution control based on the specific content requested, which is advantageous for a system that offers highly heterogenous services. We examine the performance of the Client Aware Policy (CAP) on a Linux/Apache web cluster consisting of …


Robust Face Representation And Recognition Under Low Resolution And Difficult Lighting Conditions, Mohammad Moinul Islam Apr 2002

Robust Face Representation And Recognition Under Low Resolution And Difficult Lighting Conditions, Mohammad Moinul Islam

Electrical & Computer Engineering Theses & Dissertations

This dissertation focuses on different aspects of face image analysis for accurate face recognition under low resolution and poor lighting conditions. A novel resolution enhancement technique is proposed for enhancing a low resolution face image into a high resolution image for better visualization and improved feature extraction, especially in a video surveillance environment. This method performs kernel regression and component feature learning in local neighborhood of the face images. It uses directional Fourier phase feature component to adaptively lean the regression kernel based on local covariance to estimate the high resolution image. For each patch in the neighborhood, four directional …


A Formal Object Model For Layered Networks To Support Verification And Simulation, Rasha M. B. E. Morsi Apr 2002

A Formal Object Model For Layered Networks To Support Verification And Simulation, Rasha M. B. E. Morsi

Electrical & Computer Engineering Theses & Dissertations

This work presents an abstract formal model of the interconnection structure of the Open Systems Interconnection Reference Model (OSI-RM) developed using Object-Oriented modeling principles permitting it to serve as a re-usable platform in supporting the development of simulations and formal methods applied to layered network protocols. A simulation of the object model using MODSIM III was developed and Prototype Verification System (PVS) was used to show the applicability of the object model to formal methods by formally specifying and verifying a Global Systems for Mobile communications (GSM) protocol. This application has proved to be successful in two aspects. The first …


Fabrication Techniques For Micro-Optical Device Arrays, Ryan D. Conk Mar 2002

Fabrication Techniques For Micro-Optical Device Arrays, Ryan D. Conk

Theses and Dissertations

Micro-optical devices are vital components of conventional military data storage, sensor, and communication systems. Two types of micro-optical device arrays exist: individually addressable and matrix addressable. The matrix addressable array has a drastically reduced number of metal lines and can potentially be fabricated into large, dense (over 1k elements) arrays. Such arrays are expected to enable the development of extremely high bandwidth optical interconnect systems for future military applications including optical computing and short-haul fiber optical communication systems. I investigate new fabrication techniques for the assembly of dense matrix-addressed arrays of micro-optical devices such as vertical-cavity surface-emitting lasers. Using a …


An On-Line Acid-Base Titration Applet In The Generic Tutorial System For The Sciences Project, Thomas Lee Gummo Jan 2002

An On-Line Acid-Base Titration Applet In The Generic Tutorial System For The Sciences Project, Thomas Lee Gummo

Theses Digitization Project

The purpose of this Master's Project was to develop an Acid-Base Titration Simulator. It was also to be a part of the California State University - San Bernardino's GTSS, Generic Tutorial System for the Sciences, project. The main benefit is that students will be able to conduct titration experiments over the Internet without being in the laboratory and without costly equipment or dangerous chemicals. Instructors at the high school and college level can demonstrate the key principles of titration.


Querying Geographically Dispersed, Heterogeneous Data Stores: The Pperfxchange Approach, Matthew Edward Colgrove Jan 2002

Querying Geographically Dispersed, Heterogeneous Data Stores: The Pperfxchange Approach, Matthew Edward Colgrove

Dissertations and Theses

This thesis details PPerfXchange’s approach for querying geographically dispersed heterogeneous data stores. While elements of PPerfXchange’s method have been implemented for other application areas, PPerfXchange shows how these elements can be applied to parallel performance analysis. The accomplishments of this thesis are:

  • The design of an architecture for PPerfXchange, giving a uniform method to query heterogeneous data stores;
  • A proof of concept prototype implementation of PPerfXchange including a partial implementation of an XQuery processor and a relational database virtual XML document; and
  • Evaluation of PPerfXchange using example parallel performance analysis data.


A Power Scheduling Software Package For Planetary Habitats, Gary W. Huband Jan 2002

A Power Scheduling Software Package For Planetary Habitats, Gary W. Huband

Legacy ETDs

Mankind has established a permanent presence in space with the International Space Station. The next step is building habitats on the Moon or Mars. However, these habitats will have to be nearly self-sustaining because replenishment from Earth will be costly. Power for life support and other electrical devices will be limited and must be monitored and allocated. This thesis develops the framework for power scheduling software to perform these tasks.

The software includes a graphical user interface (GUI) to allow the user to interact with the power schedule, a database and server, and a simulation for the effects of device …


Multicast Algorithms For Mobile Satellite Communication Networks, Ryan W. Thomas Mar 2001

Multicast Algorithms For Mobile Satellite Communication Networks, Ryan W. Thomas

Theses and Dissertations

With the rise of mobile computing and an increasing need for ubiquitous high speed data connections, Internet-in-the-sky solutions are becoming increasingly viable. To reduce the network overhead of one-to-many transmissions, the multicast protocol has been devised. The implementation of multicast in these Low Earth Orbit (LEO) constellations is a critical component to achieving an omnipresent network environment. This research examines the system performance associated with two terrestrial-based multicast mobility solutions, Distance Vector Multicast Routing Protocol (DVMRP) with mobile IP and On Demand Multicast Routing Protocol (ODMRP). These protocols are implemented and simulated in a six plane, 66 satellite LEO constellation. …


Design And Implementation Of An Intranet-Solution Especially With Workflow Aspects, Robert Loew Jan 2001

Design And Implementation Of An Intranet-Solution Especially With Workflow Aspects, Robert Loew

Theses

An Intranet support a new or simply an easier information system for all the workers within a company using internet technology. On the one hand, employees can use Web technology and very simple tools to provide and navigate information. On the other hand, the costly and time-consuming business of installing and maintaining software on local PCs can be avoided by using Browser-based Intranet applications. Ideally, it would be possible to access all forms of information processing using one and the same Web browser. This is the aim of the Intranet Project upon which this thesis is based.

Various technologies for …


Towards Comparative Profiling Of Parallel Applications With Pperfdb, Christian Leland Hansen Jan 2001

Towards Comparative Profiling Of Parallel Applications With Pperfdb, Christian Leland Hansen

Dissertations and Theses

Due to the complex nature of parallel programming, it is difficult to diagnose and solve performance related problems. Knowledge of program behavior is obtained experimentally, with repeated runs of a slightly modified version of the application or the same code in different environments. In these circumstances, comparative performance analysis can provide meaningful insights into the subtle effects of system and code changes on parallel program behavior by highlighting the difference in performance results across executions.

I have designed and implemented modules which extend the PPerfDB performance tool to allow access to existing performance data generated by several commonly used tracing …


Bluetooth Software On Linux, Wireless Hand-Held Devices, Teck Khoon Low Jan 2001

Bluetooth Software On Linux, Wireless Hand-Held Devices, Teck Khoon Low

Theses : Honours

In order to enable existing computers (non-Bluetooth ready) to connect to a Bluetooth piconet, a Bluetooth hardware device comprising of the Radio antenna, the baseband and control circuit is used. The digital portion of this device is also known as a Host Controller, HC. In the traditional communication lingo, the Bluetooth Hardware functions, as the Data Communication Equipment (DCE) while the Host is the Data terminal Equipment (DTE). This report discusses the theory and implementation of the communication protocol between the Host and the Host Controller, enabling communication between the computer and the Bluetooth hardware


A Distributed Agent Architecture For A Computer Virus Immune System, Paul K. Harmer Mar 2000

A Distributed Agent Architecture For A Computer Virus Immune System, Paul K. Harmer

Theses and Dissertations

Information superiority is identified as an Air Force core competency and is recognized as a key enabler for the success of future missions. Information protection and information assurance are vital components required for achieving superiority in the Infosphere, but these goals are threatened by the exponential birth rate of new computer viruses. The increased global interconnectivity that is empowering advanced information systems is also increasing the spread of malicious code and current anti-virus solutions are quickly becoming overwhelmed by the burden of capturing and classifying new viral stains. To overcome this problem, a distributed computer virus immune system (CVIS) based …


Security In Distributed Systems - A Framework For Different Application Types, Ingo Stengel Jan 2000

Security In Distributed Systems - A Framework For Different Application Types, Ingo Stengel

Theses

Security is a factor which decides upon the applicability of distributed applications. Therefore this thesis deals with security in distributed systems. The complexity of the existing distributed technologies makes it necessary to reduce the number of distributed technologies considered in this thesis, i.e. concentrating on: Java, Mobile Agents and CORBA, where only Java-based mobile agents will be considered.

After a short review of basic security principles including firewalls, existing security problems in the above mentioned distributed technologies are analysed. Additional generic problems in distributed systems are outlined.

Solutions are referring to two different areas: those regarding security problems with firewalls …


Multicast Services For Multimedia Collaborative Applications, Emad Eldin Mohamed Mohamed Jan 2000

Multicast Services For Multimedia Collaborative Applications, Emad Eldin Mohamed Mohamed

Computer Science Theses & Dissertations

This work aims at providing multicast services for multimedia collaborative applications over large inter-networks such as the Internet. Multimedia collaborative applications are typically of small group size, slow group membership dynamics, and awareness of participants' identities and locations. Moreover, they usually consist of several components such as audio, video, shared whiteboard, and single user application sharing engines that collectively help make the collaboration session successful. Each of these components has its demands from the communication layer that may differ from one component to another. This dissertation identifies the overall characteristics of multimedia collaborative applications and their individual components. It also …


Network Security Versus Network Connectivity: A Framework For Addressing The Issues Facing The Air Force Medical Community, Franklin E. Cunningham Jr. Dec 1999

Network Security Versus Network Connectivity: A Framework For Addressing The Issues Facing The Air Force Medical Community, Franklin E. Cunningham Jr.

Theses and Dissertations

The Air Force has instituted Barrier Reef to protect its networks. The Air Force medical community operates network connections that are incompatible with Barrier Reef. To overcome this problem, OASD(HA) directed the Tri-Service Management Program Office (TIMPO) to develop an architecture that protects all military health systems and allows them to link with all three services and outside partners. This research studied the underlying networking issues and formed a framework based on data from network experts from the Air Force's medical centers and their base network organizations. The findings were compared TIMPO and a composite framework was developed that more …


Two Approaches To Critical Path Scheduling For A Heterogeneous Environment, Guangxia Liu May 1999

Two Approaches To Critical Path Scheduling For A Heterogeneous Environment, Guangxia Liu

Computer Science Theses & Dissertations

Advances in computing and networking technologies are making large scale distributed heterogeneous computing a reality. Multi-Disciplinary Optimization (MDO) is a class of applications that is being addressed under this paradigm. It consists of multiple heterogeneous modules interacting with each other to solve an overall design problem. An efficient implementation of such an application requires scheduling heterogeneous modules (with different computing and disk 1/0 requirements) on a heterogeneous set of resources (with different CPU, memory, disk IO specifications).

Given a set of tasks and a set of resources, an optimal schedule of the tasks on the resources is very hard to …


Enterprise Business Objects : Design And Implementation Of A Business Object Framework, Kai-Uwe Schafer Jan 1999

Enterprise Business Objects : Design And Implementation Of A Business Object Framework, Kai-Uwe Schafer

Theses

Software components representing business entities like customer or purchase order introduce a new way of Online Transaction Processing to business applications. Collaborating business objects allow to complete whole business processes as a single distributed transaction, instead of dividing it into queued steps, which sometimes even require user intervention. This IS due to the fact that business objects contain both business data and logic and that they incorporate multiple databases from different vendors and different geographic locations in a single transaction.

Business objects cannot be used as stand-alone components, but require a framework of services that manage persistence, concurrent transactions, and …


Developing Database Applications By Using Software Components, Nusret Conk Jan 1999

Developing Database Applications By Using Software Components, Nusret Conk

Legacy ETDs

Today, the software application development process is more assembly work than a "build from scratch" approach. By placing pre-existing software components together, it is possible to create a complete application. Such components provide interfaces so that programs use them for their intended purposes. The objective of this thesis is to illustrate how software components work together to make a complete application. To illustrate the ideas and the components, this project presents a three-tiered web database application. This application, as a whole, is made up of the client side web browser, a database and the actual application programs which are Java …


Architectural Optimization Of Digital Libraries, Aileen O. Biser Aug 1998

Architectural Optimization Of Digital Libraries, Aileen O. Biser

Computer Science Theses & Dissertations

This work investigates performance and scaling issues relevant to large scale distributed digital libraries. Presently, performance and scaling studies focus on specific implementations of production or prototype digital libraries. Although useful information is gained to aid these designers and other researchers with insights to performance and scaling issues, the broader issues relevant to very large scale distributed libraries are not addressed. Specifically, no current studies look at the extreme or worst case possibilities in digital library implementations. A survey of digital library research issues is presented. Scaling and performance issues are mentioned frequently in the digital library literature but are …


The Cluster Multipole Algorithm For Far-Field Computations, Rakesh R. Patel Jul 1998

The Cluster Multipole Algorithm For Far-Field Computations, Rakesh R. Patel

Electrical & Computer Engineering Theses & Dissertations

Computer simulations of N-body systems are beneficial to study the overall behavior of a number of physical systems in fields such as astrophysics, molecular dynamics, and computational fluid dynamics. A new approach for computer simulations of N-body systems is proposed in this research. The new algorithm is called the Cluster Multipole Algorithm (CMA). The goals of the new algorithm are to improve the applicability to non-point sources and to provide more control on the accuracy over current algorithms. The algorithm is targeted to applications that do not require rebuilding the data structure about the system every time step due to …


Multiple Streams Synchronization In Collaborative Multimedia Systems, Emilia Stoica Jul 1998

Multiple Streams Synchronization In Collaborative Multimedia Systems, Emilia Stoica

Computer Science Theses & Dissertations

With the recent increase of the communication bandwidth and processor power, new types of applications have emerged. Among them, there are multimedia application, in which users are able to control, combine, and manipulate different types of media, such as text, sound, video, computer graphics, and animation. A key requirement in any multimedia application is to synchronize the delivery of various media streams to the user. To achieve this, the sender has to provide the temporal relations between the streams as they are captured. Since the receiver uses this information in streams presentation, its accuracy is very important.

Our main contribution …


A Modeling And Simulation Approach To Characterize Network Layer Internet Survivability, Leif S. King Dec 1997

A Modeling And Simulation Approach To Characterize Network Layer Internet Survivability, Leif S. King

Theses and Dissertations

The Air Force Core Competency of Information Superiority will be achieved in an age of decreasing AF manpower and corporate expertise. Increased AF reliance on COTS solutions, coupled with nearly ubiquitous points of entry to communication networks, create unique challenges in maintaining the Information Superiority edge. The protection of the internet is part of this equation. The internet supports the daily business traffic of the Air Force. Personnel, finance, and supply data flow through its routers. Controlling an adversary's access to our information systems, either the data, or the hardware and software that control the data and transform it into …