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 Department: Department of Computer Science
 Collection: UNT Theses and Dissertations
Impact of actual interference on capacity and call admission control in a CDMA network.

Impact of actual interference on capacity and call admission control in a CDMA network.

Date: May 2004
Creator: Parvez, Asad
Description: An overwhelming number of models in the literature use average inter-cell interference for the calculation of capacity of a Code Division Multiple Access (CDMA) network. The advantage gained in terms of simplicity by using such models comes at the cost of rendering the exact location of a user within a cell irrelevant. We calculate the actual per-user interference and analyze the effect of user-distribution within a cell on the capacity of a CDMA network. We show that even though the capacity obtained using average interference is a good approximation to the capacity calculated using actual interference for a uniform user distribution, the deviation can be tremendously large for non-uniform user distributions. Call admission control (CAC) algorithms are responsible for efficient management of a network's resources while guaranteeing the quality of service and grade of service, i.e., accepting the maximum number of calls without affecting the quality of service of calls already present in the network. We design and implement global and local CAC algorithms, and through simulations compare their network throughput and blocking probabilities for varying mobility scenarios. We show that even though our global CAC is better at resource management, the lack of substantial gain in network throughput and ...
Contributing Partner: UNT Libraries
DICOM Image Scrubbing Software Library/Utility

DICOM Image Scrubbing Software Library/Utility

Date: May 2003
Creator: Ponnam, Bhavani Srikanth
Description: This software is aimed at providing user-friendly, easy-to-use environment for the user to scrub (de-identify/modify) the DICOM header information. Some tools either anonymize or default the values without the user interaction. The user doesn't have the flexibility to edit the header information. One cannot scrub set of images simultaneously (batch scrubbing). This motivated to develop a tool/utility that can scrub a set of images in a single step more efficiently. This document also addresses security issues of the patient confidentiality to achieve protection of patient identifying information and some technical requirements
Contributing Partner: UNT Libraries
Agent-based architecture for web deployment of multi-agents as conversational interfaces.

Agent-based architecture for web deployment of multi-agents as conversational interfaces.

Date: May 2003
Creator: Pothuru, Ranjit Kumar
Description: Agent-based architecture explains the rationale and basis for developing agents that can interact with users through natural language query/answer patterns developed systematically using AIML (artificial intelligence mark-up language) scripts. This thesis research document also explains the architecture for VISTA (virtual interactive story-telling agents), which is used for interactive querying in educational and recreational purposes. Agents are very effective as conversational interfaces when used along side with graphical user interface (GUI) in applications and Web pages. This architecture platform can support multiple agents with or with out sharing of knowledgebase. They are very useful as chat robots for recreational purposes, customer service and educational purposes. This platform is powered by Java servlet implementation of Program D and contained in Apache Tomcat server. The AIML scripting language defined here in is a generic form of XML language and forms the knowledgebase of the bot. Animation is provided with Microsoft® Agent technology and text-to-speech support engine.
Contributing Partner: UNT Libraries
A Security Model for Mobile Agents using X.509 Proxy Certificates

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

Date: December 2002
Creator: Raghunathan, Subhashini
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 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.
Contributing Partner: UNT Libraries
Evaluation of MPLS Enabled Networks

Evaluation of MPLS Enabled Networks

Access: Use of this item is restricted to the UNT Community.
Date: May 2003
Creator: Ratnakaram, Archith
Description: Recent developments in the Internet have inspired a wide range of business and consumer applications. The deployment of multimedia-based services has driven the demand for increased and guaranteed bandwidth requirements over the network. The diverse requirements of the wide range of users demand differentiated classes of service and quality assurance. The new technology of Multi-protocol label switching (MPLS) has emerged as a high performance and reliable option to address these challenges apart from the additional features that were not addressed before. This problem in lieu of thesis describes how the new paradigm of MPLS is advantageous over the conventional architecture. The motivation for this paradigm is discussed in the first part, followed by a detailed description of this new architecture. The information flow, the underlying protocols and the MPLS extensions to some of the traditional protocols are then discussed followed by the description of the simulation. The simulation results are used to show the advantages of the proposed technology.
Contributing Partner: UNT Libraries
Dynamic Grid-Based Data Distribution Management in Large Scale Distributed Simulations

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

Date: December 2000
Creator: Roy, Amber Joyce
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 applications that require them. In this thesis, we propose a new DDM scheme, which we refer to as dynamic grid-based DDM. A lightweight UNT-RTI has been developed and implemented to investigate the performance of our DDM scheme. Our results clearly indicate that our scheme is scalable and it significantly reduces both the number of multicast groups used, and the message overhead, when compared to previous grid-based allocation schemes using large-scale and real-world scenarios.
Contributing Partner: UNT Libraries
Security problems in 802.11 wireless networks standard due to the inefficiency of wired equivalent privacy protocol.

Security problems in 802.11 wireless networks standard due to the inefficiency of wired equivalent privacy protocol.

Date: May 2003
Creator: Samanthapudi, Varma
Description: Due to the rapid growth of wireless networking, the fallible security issues of the 802.11 standard have come under close scrutiny. Nowadays most of the organizations are eager to setup wireless local area networks to reduce the hassles of limited mobility provided by conventional wired network. There are serious security issues that need to be sorted out before everyone is willing to transmit valuable corporate information on a wireless network. This report documents the inherent flaws in wired equivalent privacy protocol used by the 802.11 standard and the ensuing security breaches that can occur to a wireless network due to these flaws. The solutions suggested in this report might not actually make the 802.11 standard secure, but will surely help in the lead up to a secure wireless network standard.
Contributing Partner: UNT Libraries
OLAP Services

OLAP Services

Access: Use of this item is restricted to the UNT Community.
Date: December 2003
Creator: Sanghvi, Rajendra
Description: On-line Analytical Processing (OLAP) is a very interesting platform to provide analytical power to the data present in the database. This paper discusses the system designed which handles integration of data from two remote legacy reservation systems to merge as one Integrated database server and also the design of an OLAP database and building an OLAP cube for the data warehousing. OLAP cube is useful for analysis of data and also for making various business decisions. The Data Transformation Services (DTS) in the Microsoft® SQL Server 2000 is used to integrate as a package the collection of data and also for refreshing data in the databases. On-line Analytical Processing (OLAP) cube is designed using Microsoft® Analysis Server.
Contributing Partner: UNT Libraries
A general purpose semantic parser using FrameNet and WordNet®.

A general purpose semantic parser using FrameNet and WordNet®.

Date: May 2004
Creator: Shi, Lei
Description: Syntactic parsing is one of the best understood language processing applications. Since language and grammar have been formally defined, it is easy for computers to parse the syntactic structure of natural language text. Does meaning have structure as well? If it has, how can we analyze the structure? Previous systems rely on a one-to-one correspondence between syntactic rules and semantic rules. But such systems can only be applied to limited fragments of English. In this thesis, we propose a general-purpose shallow semantic parser which utilizes a semantic network (WordNet), and a frame dataset (FrameNet). Semantic relations recognized by the parser are based on how human beings represent knowledge of the world. Parsing semantic structure allows semantic units and constituents to be accessed and processed in a more meaningful way than syntactic parsing, moving the automation of understanding natural language text to a higher level.
Contributing Partner: UNT Libraries
A Unifying Version Model for Objects and Schema in Object-Oriented Database System

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

Date: August 1997
Creator: Shin, Dongil
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 than previous systems. Also, programmers need know only one set of versioning operations; thus, reducing the learning time by half. This dissertation shows that UVM is a simple but semantically sound and powerful version model for both objects and schema.
Contributing Partner: UNT Libraries