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  Partner: UNT Libraries
 Department: Department of Computer Science
 Collection: UNT Theses and Dissertations
Secret Key Agreement without Public-Key Cryptography

Secret Key Agreement without Public-Key Cryptography

Access: Use of this item is restricted to the UNT Community.
Date: August 2003
Creator: Surapaneni, Smitha
Description: Secure communication is the primary challenge in today's information network. In this project an efficient secret key agreement protocol is described and analyzed along with the other existing protocols. We focus primarily on Leighton and Micali's secret-key agreement without the use of public-key encryption techniques. The Leighton-Micali protocol is extremely efficient when implemented in software and has significant advantages over existing systems like Kerberos. In this method the secret keys are agreed upon using a trusted third party known as the trusted agent. The trusted agent generates the keys and writes them to a public directory before it goes offline. The communicating entities can retrieve the keys either from the online trusted agent or from the public directory service and agree upon a symmetric-key without any public-key procedures. The principal advantage of this method is that the user verifies the authenticity of the trusted agent before using the keys generated by it. The Leighton-Micali scheme is not vulnerable to the present day attacks like fabrication, modification or denial of service etc. The Leighton-Micali protocol can be employed in real-time systems like smart cards. In addition to the security properties and the simplicity of the protocol, our experiments show that in ...
Contributing Partner: UNT Libraries
Refactoring FrameNet for Efficient Relational Queries

Refactoring FrameNet for Efficient Relational Queries

Date: December 2003
Creator: Ahmad, Zeeshan Asim
Description: The FrameNet database is being used in a variety of NLP research and applications such as word sense disambiguation, machine translation, information extraction and question answering. The database is currently available in XML format. The XML database though a wholesome way of distributing data in its entireness, is not practical for use unless converted to a more application friendly database. In light of this we have successfully converted the XML database to a relational MySQL™ database. This conversion reduced the amount of data storage amount to less than half. Most importantly the new database enables us to perform fast complex querying and facilitates use by applications and research. We show the steps taken to ensure relational integrity of the data during the refactoring process and a simple demo application demonstrating ease of use.
Contributing Partner: UNT Libraries
Case-Based Reasoning (CBR) for Children Story Selection in ASP.NET and C#

Case-Based Reasoning (CBR) for Children Story Selection in ASP.NET and C#

Date: December 2003
Creator: Hu, Demin
Description: This paper describes the general architecture and function of a Case-Based Reasoning (CBR) system implemented with ASP.NET and C#. Microsoft Visual Studio .NET and XML Web Services provide a flexible, standards-based model that allows clients to access data. Web Form Pages offer a powerful programming model for Web-enabled user interface. The system provides a variety of mechanisms and services related to story retrieval and adaptation. Users may browse and search a library of text stories. More advanced CBR capabilities were also implemented, including a multi-factor distance-calculation for matching user interests with stories in the library, recommendations on optimizing search, and adaptation of stories to match user interests.
Contributing Partner: UNT Libraries
Embedded monitors for detecting and preventing intrusions in cryptographic and application protocols.

Embedded monitors for detecting and preventing intrusions in cryptographic and application protocols.

Date: December 2003
Creator: Joglekar, Sachin P.
Description: There are two main approaches for intrusion detection: signature-based and anomaly-based. Signature-based detection employs pattern matching to match attack signatures with observed data making it ideal for detecting known attacks. However, it cannot detect unknown attacks for which there is no signature available. Anomaly-based detection builds a profile of normal system behavior to detect known and unknown attacks as behavioral deviations. However, it has a drawback of a high false alarm rate. In this thesis, we describe our anomaly-based IDS designed for detecting intrusions in cryptographic and application-level protocols. Our system has several unique characteristics, such as the ability to monitor cryptographic protocols and application-level protocols embedded in encrypted sessions, a very lightweight monitoring process, and the ability to react to protocol misuse by modifying protocol response directly.
Contributing Partner: UNT Libraries
A Comparison of Agent-Oriented Software Engineering Frameworks and Methodologies

A Comparison of Agent-Oriented Software Engineering Frameworks and Methodologies

Date: December 2003
Creator: Lin, Chia-En
Description: Agent-oriented software engineering (AOSE) covers issues on developing systems with software agents. There are many techniques, mostly agent-oriented and object-oriented, ready to be chosen as building blocks to create agent-based systems. There have been several AOSE methodologies proposed intending to show engineers guidelines on how these elements are constituted in having agents achieve the overall system goals. Although these solutions are promising, most of them are designed in ad-hoc manner without truly obeying software developing life-cycle fully, as well as lacking of examinations on agent-oriented features. To address these issues, we investigated state-of-the-art techniques and AOSE methodologies. By examining them in different respects, we commented on the strength and weakness of them. Toward a formal study, a comparison framework has been set up regarding four aspects, including concepts and properties, notations and modeling techniques, process, and pragmatics. Under these criteria, we conducted the comparison in both overview and detailed level. The comparison helped us with empirical and analytical study, to inspect the issues on how an ideal agent-based system will be formed.
Contributing Partner: UNT Libraries
Intelligent Memory Management Heuristics

Intelligent Memory Management Heuristics

Date: December 2003
Creator: Panthulu, Pradeep
Description: Automatic memory management is crucial in implementation of runtime systems even though it induces a significant computational overhead. In this thesis I explore the use of statistical properties of the directed graph describing the set of live data to decide between garbage collection and heap expansion in a memory management algorithm combining the dynamic array represented heaps with a mark and sweep garbage collector to enhance its performance. The sampling method predicting the density and the distribution of useful data is implemented as a partial marking algorithm. The algorithm randomly marks the nodes of the directed graph representing the live data at different depths with a variable probability factor p. Using the information gathered by the partial marking algorithm in the current step and the knowledge gathered in the previous iterations, the proposed empirical formula predicts with reasonable accuracy the density of live nodes on the heap, to decide between garbage collection and heap expansion. The resulting heuristics are tested empirically and shown to improve overall execution performance significantly in the context of the Jinni Prolog compiler's runtime system.
Contributing Partner: UNT Libraries
Machine Language Techniques for Conversational Agents

Machine Language Techniques for Conversational Agents

Date: December 2003
Creator: Sule, Manisha D.
Description: Machine Learning is the ability of a machine to perform better at a given task, using its previous experience. Various algorithms like decision trees, Bayesian learning, artificial neural networks and instance-based learning algorithms are used widely in machine learning systems. Current applications of machine learning include credit card fraud detection, customer service based on history of purchased products, games and many more. The application of machine learning techniques to natural language processing (NLP) has increased tremendously in recent years. Examples are handwriting recognition and speech recognition. The problem we tackle in this Problem in Lieu of Thesis is applying machine-learning techniques to improve the performance of a conversational agent. The OpenMind repository of common sense, in the form of question-answer pairs is treated as the training data for the machine learning system. WordNet is interfaced with to capture important semantic and syntactic information about the words in the sentences. Further, k-closest neighbors algorithm, an instance based learning algorithm is used to simulate a case based learning system. The resulting system is expected to be able to answer new queries with knowledge gained from the training data it was fed with.
Contributing Partner: UNT Libraries
Agent extensions for peer-to-peer networks.

Agent extensions for peer-to-peer networks.

Date: December 2003
Creator: Valiveti, Kalyan
Description: Peer-to-Peer (P2P) networks have seen tremendous growth in development and usage in recent times. This attention has brought many developments as well as new challenges to these networks. We will show that agent extensions to P2P networks offer solutions to many problems faced by P2P networks. In this research, an attempt is made to bring together JXTA P2P infrastructure and Jinni, a Prolog based agent engine to form an agent based P2P network. On top of the JXTA, we define simple Java API providing P2P services for agent programming constructs. Jinni is deployed on this JXTA network using an automated code update mechanism. Experiments are conducted on this Jinni/JXTA platform to implement a simple agent communication and data exchange protocol.
Contributing Partner: UNT Libraries
Performance Evaluation of Data Integrity Mechanisms for Mobile Agents

Performance Evaluation of Data Integrity Mechanisms for Mobile Agents

Access: Use of this item is restricted to the UNT Community.
Date: December 2003
Creator: Gunupudi, Vandana
Description: With the growing popularity of e-commerce applications that use software agents, the protection of mobile agent data has become imperative. To that end, the performance of four methods that protect the data integrity of mobile agents is evaluated. The methods investigated include existing approaches known as the Partial Result Authentication Codes, Hash Chaining, and Set Authentication Code methods, and a technique of our own design, called the Modified Set Authentication Code method, which addresses the limitations of the Set Authentication Code method. The experiments were run using the DADS agent system (developed at the Network Research Laboratory at UNT), for which a Data Integrity Module was designed. The experimental results show that our Modified Set Authentication Code technique performed comparably to the Set Authentication Code method.
Contributing Partner: UNT Libraries
Self-Optimizing Dynamic Finite Functions

Self-Optimizing Dynamic Finite Functions

Access: Use of this item is restricted to the UNT Community.
Date: December 2003
Creator: Jeripothula, Ramesh
Description: Finite functions (also called maps) are used to describe a number of key computations and storage mechanisms used in software and hardware interpreters. Their presence spread over various memory and speed hierarchies in hardware and through various optimization processes (algorithmic and compilation based) in software, suggests encapsulating dynamic size changes and representation optimizations in a unique abstraction to be used across traditional computation mechanisms. We developed a memory allocator for testing the finite functions. We have implemented some dynamic finite functions and performed certain experiments to see the performance speed of these finite functions. We have developed some simple but powerful application programming interfaces (API) for these finite functions.
Contributing Partner: UNT Libraries