UNT Libraries - 119 Matching Results

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open access

A Security Model for Mobile Agents using X.509 Proxy Certificates

Description: Mobile agent technology presents an attractive alternative to the client-server paradigm for several network and real-time applications. However, for most applications, the lack of a viable agent security model has limited the adoption of the agent paradigm. This thesis presents a security model for mobile agents based on a security infrastructure for Computational Grids, and specifically, on X.509 Proxy Certificates. Proxy Certificates serve as credentials for Grid applications, and their prim… more
Date: December 2002
Creator: Raghunathan, Subhashini
Item Type: Refine your search to only Thesis or Dissertation

Server load balancing.

Description: Server load balancing technology has obtained much attention as much business proceeded towards e-commerce. The idea behind is to have set of clustered servers that share the load as against a single server to achieve better performance and throughput. In this problem in lieu of thesis, I propose and evaluate an implementation of a prototype scalable server. The prototype consists of a load-balanced cluster of hosts that collectively accept and service TCP connections. The host IP addresses are… more
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Date: December 2002
Creator: Kanuri, Jaichandra
Item Type: Refine your search to only Thesis or Dissertation
open access

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, … more
Date: August 2002
Creator: Battula, Venkata Krishna Rao
Item Type: Refine your search to only Thesis or Dissertation
open access

The Design and Implementation of a Prolog Parser Using Javacc

Description: Operatorless Prolog text is LL(1) in nature and any standard LL parser generator tool can be used to parse it. However, the Prolog text that conforms to the ISO Prolog standard allows the definition of dynamic operators. Since Prolog operators can be defined at run-time, operator symbols are not present in the grammar rules of the language. Unless the parser generator allows for some flexibility in the specification of the grammar rules, it is very difficult to generate a parser for such text. … more
Date: August 2002
Creator: Gupta, Pankaj
Item Type: Refine your search to only Thesis or Dissertation

Developing a Test Bed for Interactive Narrative in Virtual Environments

Description: As Virtual Environments (VE) become a more commonly used method of interaction and presentation, supporting users as they navigate and interact with scenarios presented in VE will be a significant issue. A key step in understanding the needs of users in these situations will be observing them perform representative tasks in a fully developed environment. In this paper, we describe the development of a test bed for interactive narrative in a virtual environment. The test bed was specifically dev… more
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Date: August 2002
Creator: Mellacheruvu, Krishna
Item Type: Refine your search to only Thesis or Dissertation

Implementation of Scalable Secure Multicasting

Description: A large number of applications like multi-player games, video conferencing, chat groups and network management are presently based on multicast communication. As the group communication model is being deployed for mainstream use, it is critical to provide security mechanisms that facilitate confidentiality, authenticity and integrity in group communications. Providing security in multicast communication requires addressing the problem of scalability in group key distribution. Scalability is a c… more
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Date: August 2002
Creator: Vellanki, Ramakrishnaprasad
Item Type: Refine your search to only Thesis or Dissertation
open access

Visualization of Surfaces and 3D Vector Fields

Description: Visualization of trivariate functions and vector fields with three components in scientific computation is still a hard problem in compute graphic area. People build their own visualization packages for their special purposes. And there exist some general-purpose packages (MatLab, Vis5D), but they all require extensive user experience on setting all the parameters in order to generate images. We present a simple package to produce simplified but productive images of 3-D vector fields. We used t… more
Date: August 2002
Creator: Li, Wentong
Item Type: Refine your search to only Thesis or Dissertation

A Study of Perceptually Tuned, Wavelet Based, Rate Scalable, Image and Video Compression

Description: In this dissertation, first, we have proposed and implemented a new perceptually tuned wavelet based, rate scalable, and color image encoding/decoding system based on the human perceptual model. It is based on state-of-the-art research on embedded wavelet image compression technique, Contrast Sensitivity Function (CSF) for Human Visual System (HVS) and extends this scheme to handle optimal bit allocation among multiple bands, such as Y, Cb, and Cr. Our experimental image codec shows very exciti… more
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Date: May 2002
Creator: Wei, Ming
Item Type: Refine your search to only Thesis or Dissertation
open access

Dynamic Resource Management in RSVP- Controlled Unicast Networks

Description: Resources are said to be fragmented in the network when they are available in non-contiguous blocks, and calls are dropped as they may not end sufficient resources. Hence, available resources may remain unutilized. In this thesis, the effect of resource fragmentation (RF) on RSVP-controlled networks was studied and new algorithms were proposed to reduce the effect of RF. In order to minimize the effect of RF, resources in the network are dynamically redistributed on different paths to make the… more
Date: December 2001
Creator: Iyengar Prasanna, Venkatesan
Item Type: Refine your search to only Thesis or Dissertation
open access

Higher Compression from the Burrows-Wheeler Transform with New Algorithms for the List Update Problem

Description: Burrows-Wheeler compression is a three stage process in which the data is transformed with the Burrows-Wheeler Transform, then transformed with Move-To-Front, and finally encoded with an entropy coder. Move-To-Front, Transpose, and Frequency Count are some of the many algorithms used on the List Update problem. In 1985, Competitive Analysis first showed the superiority of Move-To-Front over Transpose and Frequency Count for the List Update problem with arbitrary data. Earlier studies due to Bit… more
Date: August 2001
Creator: Chapin, Brenton
Item Type: Refine your search to only Thesis or Dissertation
open access

Extensions to Jinni Mobile Agent Architecture

Description: We extend the Jinni mobile agent architecture with a multicast network transport layer, an agent-to-agent delegation mechanism and a reflection based Prolog-to-Java interface. To ensure that our agent infrastructure runs efficiently, independently of router-level multicast support, we describe a blackboard based algorithm for locating a randomly roaming agent. As part of the agent-to-agent delegation mechanism, we describe an alternative to code-fetching mechanism for stronger mobility of mobil… more
Date: May 2001
Creator: Tyagi, Satyam
Item Type: Refine your search to only Thesis or Dissertation

Temporally Correct Algorithms for Transaction Concurrency Control in Distributed Databases

Description: Many activities are comprised of temporally dependent events that must be executed in a specific chronological order. Supportive software applications must preserve these temporal dependencies. Whenever the processing of this type of an application includes transactions submitted to a database that is shared with other such applications, the transaction concurrency control mechanisms within the database must also preserve the temporal dependencies. A basis for preserving temporal dependencies i… more
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Date: May 2001
Creator: Tuck, Terry W.
Item Type: Refine your search to only Thesis or Dissertation
open access

Dynamic Grid-Based Data Distribution Management in Large Scale Distributed Simulations

Description: Distributed simulation is an enabling concept to support the networked interaction of models and real world elements that are geographically distributed. This technology has brought a new set of challenging problems to solve, such as Data Distribution Management (DDM). The aim of DDM is to limit and control the volume of the data exchanged during a distributed simulation, and reduce the processing requirements of the simulation hosts by relaying events and state information only to those applic… more
Date: December 2000
Creator: Roy, Amber Joyce
Item Type: Refine your search to only Thesis or Dissertation
open access

Algorithms for Efficient Utilization of Wireless Bandwidth and to Provide Quality-of-Service in Wireless Networks

Description: This thesis presents algorithms to utilize the wireless bandwidth efficiently and at the same time meet the quality of service (QoS) requirements of the users. In the proposed algorithms we present an adaptive frame structure based upon the airlink frame loss probability and control the admission of call requests into the system based upon the load on the system and the QoS requirements of the incoming call requests. The performance of the proposed algorithms is studied by developing analytical… more
Date: August 2000
Creator: Kakani, Naveen Kumar
Item Type: Refine your search to only Thesis or Dissertation

Multi-Agent Architecture for Internet Information Extraction and Visualization

Description: The World Wide Web is one of the largest sources of information; more and more applications are being developed daily to make use of this information. This thesis presents a multi-agent architecture that deals with some of the issues related to Internet data extraction. The primary issue addresses the reliable, efficient and quick extraction of data through the use of HTTP performance monitoring agents. A second issue focuses on how to make use of available data to take decisions and alert the … more
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Date: August 2000
Creator: Gollapally, Devender R.
Item Type: Refine your search to only Thesis or Dissertation
open access

The Design and Implementation of an Intelligent Agent-Based File System

Description: As bandwidth constraints on LAN/WAN environments decrease, the demand for distributed services will continue to increase. In particular, the proliferation of user-level applications requiring high-capacity distributed file storage systems will demand that such services be universally available. At the same time, the advent of high-speed networks have made the deployment of application and communication solutions based upon an Intelligent Mobile Agent (IMA) framework practical. Agents have prove… more
Date: May 2000
Creator: Hopper, S. Andrew
Item Type: Refine your search to only Thesis or Dissertation
open access

An Adaptive Linearization Method for a Constraint Satisfaction Problem in Semiconductor Device Design Optimization

Description: The device optimization is a very important element in semiconductor technology advancement. Its objective is to find a design point for a semiconductor device so that the optimized design goal meets all specified constraints. As in other engineering fields, a nonlinear optimizer is often used for design optimization. One major drawback of using a nonlinear optimizer is that it can only partially explore the design space and return a local optimal solution. This dissertation provides an adaptiv… more
Date: May 1999
Creator: Chang, Chih-Hui, 1967-
Item Type: Refine your search to only Thesis or Dissertation
open access

Computational Complexity of Hopfield Networks

Description: There are three main results in this dissertation. They are PLS-completeness of discrete Hopfield network convergence with eight different restrictions, (degree 3, bipartite and degree 3, 8-neighbor mesh, dual of the knight's graph, hypercube, butterfly, cube-connected cycles and shuffle-exchange), exponential convergence behavior of discrete Hopfield network, and simulation of Turing machines by discrete Hopfield Network.
Date: August 1998
Creator: Tseng, Hung-Li
Item Type: Refine your search to only Thesis or Dissertation
open access

Exon/Intron Discrimination Using the Finite Induction Pattern Matching Technique

Description: DNA sequence analysis involves precise discrimination of two of the sequence's most important components: exons and introns. Exons encode the proteins that are responsible for almost all the functions in a living organism. Introns interrupt the sequence coding for a protein and must be removed from primary RNA transcripts before translation to protein can occur. A pattern recognition technique called Finite Induction (FI) is utilized to study the language of exons and introns. FI is especially… more
Date: December 1997
Creator: Taylor, Pamela A., 1941-
Item Type: Refine your search to only Thesis or Dissertation
open access

A Unifying Version Model for Objects and Schema in Object-Oriented Database System

Description: There have been a number of different versioning models proposed. The research in this area can be divided into two categories: object versioning and schema versioning. In this dissertation, both problem domains are considered as a single unit. This dissertation describes a unifying version model (UVM) for maintaining changes to both objects and schema. UVM handles schema versioning operations by using object versioning techniques. The result is that the UVM allows the OODBMS to be much smaller… more
Date: August 1997
Creator: Shin, Dongil
Item Type: Refine your search to only Thesis or Dissertation
open access

Automatic Speech Recognition Using Finite Inductive Sequences

Description: This dissertation addresses the general problem of recognition of acoustic signals which may be derived from speech, sonar, or acoustic phenomena. The specific problem of recognizing speech is the main focus of this research. The intention is to design a recognition system for a definite number of discrete words. For this purpose specifically, eight isolated words from the T1MIT database are selected. Four medium length words "greasy," "dark," "wash," and "water" are used. In addition, four sho… more
Date: August 1996
Creator: Cherri, Mona Youssef, 1956-
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open access

A Machine Learning Method Suitable for Dynamic Domains

Description: The efficacy of a machine learning technique is domain dependent. Some machine learning techniques work very well for certain domains but are ill-suited for other domains. One area that is of real-world concern is the flexibility with which machine learning techniques can adapt to dynamic domains. Currently, there are no known reports of any system that can learn dynamic domains, short of starting over (i.e., re-running the program). Starting over is neither time nor cost efficient for real-wor… more
Date: July 1996
Creator: Rowe, Michael C. (Michael Charles)
Item Type: Refine your search to only Thesis or Dissertation
open access

Symplectic Integration of Nonseparable Hamiltonian Systems

Description: Numerical methods are usually necessary in solving Hamiltonian systems since there is often no closed-form solution. By utilizing a general property of Hamiltonians, namely the symplectic property, all of the qualities of the system may be preserved for indefinitely long integration times because all of the integral (Poincare) invariants are conserved. This allows for more reliable results and frequently leads to significantly shorter execution times as compared to conventional methods. The res… more
Date: May 1996
Creator: Curry, David M. (David Mason)
Item Type: Refine your search to only Thesis or Dissertation
open access

Convexity-Preserving Scattered Data Interpolation

Description: Surface fitting methods play an important role in many scientific fields as well as in computer aided geometric design. The problem treated here is that of constructing a smooth surface that interpolates data values associated with scattered nodes in the plane. The data is said to be convex if there exists a convex interpolant. The problem of convexity-preserving interpolation is to determine if the data is convex, and construct a convex interpolant if it exists.
Date: December 1995
Creator: Leung, Nim Keung
Item Type: Refine your search to only Thesis or Dissertation
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