DirectShow Approach to Low-Cost Multimedia Security Surveillance System (open access)

DirectShow Approach to Low-Cost Multimedia Security Surveillance System

In response to the recent intensive needs for civilian security surveillance, both full and compact versions of a Multimedia Security Surveillance (MSS) system have been built up. The new Microsoft DirectShow technology was applied in implementing the multimedia stream-processing module. Through Microsoft Windows Driver Model interface, the chosen IEEE1394 enabled Fire-i cameras as external sensors are integrated with PC based continuous storage unit. The MSS application also allows multimedia broadcasting and remote controls. Cost analysis is included.
Date: December 2002
Creator: Xiao, Wu
System: The UNT Digital Library
An Annotated Bibliography of Mobile Agents in Networks (open access)

An Annotated Bibliography of Mobile Agents in Networks

The purpose of this thesis is to present a comprehensive colligation of applications of mobile agents in networks, and provide a baseline association of these systems. This work has been motivated by the fact that mobile agent systems have been deemed proficuous alternatives in system applications. Several mobile agent systems have been developed to provide scalable and cogent solutions in network-centric applications. This thesis examines some existing mobile agent systems in core networking areas, in particular, those of network and resource management, routing, and the provision of fault tolerance and security. The inherent features of these systems are discussed with respect to their specific functionalities. The applicability and efficacy of mobile agents are further considered in the specific areas mentioned above. Although an initial foray into a collation of this nature, the goal of this annotated bibliography is to provide a generic referential view of mobile agent systems in network applications.
Date: December 2002
Creator: Sriraman, Sandhya
System: The UNT Digital Library
A Security Model for Mobile Agents using X.509 Proxy Certificates (open access)

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

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 primary purpose is temporary delegation of authority. Exploiting the similarity between Grid applications and mobile agent applications, this thesis motivates the use of Proxy Certificates as credentials for mobile agents. A new extension for Proxy Certificates is proposed in order to make them suited to mobile agent applications, and mechanisms are presented for agent-to-host authentication, restriction of agent privileges, and secure delegation of authority during spawning of new agents. Finally, the implementation of the proposed security mechanisms as modules within a multi-lingual and modular agent infrastructure, the Distributed Agent Delivery System, is discussed.
Date: December 2002
Creator: Raghunathan, Subhashini
System: The UNT Digital Library
DADS - A Distributed Agent Delivery System (open access)

DADS - A Distributed Agent Delivery System

Mobile agents require an appropriate platform that can facilitate their migration and execution. In particular, the design and implementation of such a system must balance several factors that will ensure that its constituent agents are executed without problems. Besides the basic requirements of migration and execution, an agent system must also provide mechanisms to ensure the security and survivability of an agent when it migrates between hosts. In addition, the system should be simple enough to facilitate its widespread use across large scale networks (i.e Internet). To address these issues, this thesis discusses the design and implementation of the Distributed Agent Delivery System (DADS). The DADS provides a de-coupled design that separates agent acceptance from agent execution. Using functional modules, the DADS provides services ranging from language execution and security to fault-tolerance and compression. Modules allow the administrator(s) of hosts to declare, at run-time, the services that they want to provide. Since each administrative domain is different, the DADS provides a platform that can be adapted to exchange heterogeneous blends of agents across large scale networks.
Date: December 2002
Creator: Cozzolino, Clifford Joseph
System: The UNT Digital Library
Visualization of Surfaces and 3D Vector Fields (open access)

Visualization of Surfaces and 3D Vector Fields

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 this method to render the magnetic field and current as solutions of the Ginzburg-Landau equations on a 3-D domain.
Date: August 2002
Creator: Li, Wentong
System: The UNT Digital Library
The Design and Implementation of a Prolog Parser Using Javacc (open access)

The Design and Implementation of a Prolog Parser Using Javacc

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. In this thesis we discuss the existing parsing methods and their modified versions to parse languages with dynamic operator capabilities. Implementation details of a parser using Javacc as a parser generator tool to parse standard Prolog text is provided. The output of the parser is an “Abstract Syntax Tree” that reflects the correct precedence and associativity rules among the various operators (static and dynamic) of the language. Empirical results are provided that show that a Prolog parser that is generated by the parser generator like Javacc is comparable in efficiency to a hand-coded parser.
Date: August 2002
Creator: Gupta, Pankaj
System: The UNT Digital Library
Control Mechanisms and Recovery Techniques for Real-Time Data Transmission Over the Internet. (open access)

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

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 …
Date: August 2002
Creator: Battula, Venkata Krishna Rao
System: The UNT Digital Library