Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Computer Sciences

Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 24661 - 24690 of 27793

Full-Text Articles in Entire DC Network

Using Sequence Analysis To Perform Application-Based Anomaly Detection Within An Artificial Immune System Framework, Larissa A. O'Brien Mar 2003

Using Sequence Analysis To Perform Application-Based Anomaly Detection Within An Artificial Immune System Framework, Larissa A. O'Brien

Theses and Dissertations

The Air Force and other Department of Defense (DoD) computer systems typically rely on traditional signature-based network IDSs to detect various types of attempted or successful attacks. Signature-based methods are limited to detecting known attacks or similar variants; anomaly-based systems, by contrast, alert on behaviors previously unseen. The development of an effective anomaly-detecting, application based IDS would increase the Air Force's ability to ward off attacks that are not detected by signature-based network IDSs, thus strengthening the layered defenses necessary to acquire and maintain safe, secure communication capability. This system follows the Artificial Immune System (AIS) framework, which relies on …


Searching System Call Information For Clues: The Effects Of Intrusions Of Processes, Mark G. Reith Mar 2003

Searching System Call Information For Clues: The Effects Of Intrusions Of Processes, Mark G. Reith

Theses and Dissertations

The United States Air Force extensively uses information systems as a tool managing and maintaining its information. The increased dependence on these systems in recent years has necessitated the need for protection front threats of information warfare and cyber terrorism. One type of protection utilizes intrusion detection systems to provide indications that intrusive behavior has occurred. Other types of protection may include packet filtering, cryptography and strong user authentication. Traditional approaches toward intrusion detection rely on features that are external to computer processes. By treating processes as black-boxes, intrusion detection systems may miss a wealth of information that could be …


The Generalizability Of Private Sector Research On Software Project Management In Two Usaf Organizations: An Exploratory Study, Michael R. Garman Mar 2003

The Generalizability Of Private Sector Research On Software Project Management In Two Usaf Organizations: An Exploratory Study, Michael R. Garman

Theses and Dissertations

Project managers typically set three success criteria for their projects: meet specifications, be on time, and be on budget. However, software projects frequently fail to meet these criteria. Software engineers, acquisition officers, and project managers have all studied this issue and made recommendations for achieving success. But most of this research in peer reviewed journals has focused on the private sector. Researchers have also identified software acquisitions as one of the major differences between the private sector and public sector MIS. This indicates that the elements for a successful software project in the public sector may be different from the …


The Effect Of Interactivity And Instructional Exposure On Learning Effectiveness And Knowledge Retention: A Comparative Study Of Two U.S. Air Force Computer-Based Training (Cbt) Courses For Network User Licensing, Matthew J. Imperial Mar 2003

The Effect Of Interactivity And Instructional Exposure On Learning Effectiveness And Knowledge Retention: A Comparative Study Of Two U.S. Air Force Computer-Based Training (Cbt) Courses For Network User Licensing, Matthew J. Imperial

Theses and Dissertations

The United States Air Force (USAF) currently employs the use of computer-based training (CET) across a host of requirements. One such requirement is in the Information Assurance (IA) arena and involves the training/licensing of over one-million computer network end-users. USAF use of CETs has been shown to possess a potential for substantial fiscal savings. However, studies investigating the learning outcomes of learning effectiveness (initial learning) and knowledge retention (sustained learning) associated with USAF CETs are lacking.


Text Manipulation Judgment Accuracy: An Exploratory Study, Randy S. Wardak Mar 2003

Text Manipulation Judgment Accuracy: An Exploratory Study, Randy S. Wardak

Theses and Dissertations

Deception aims to affect a decision-making process in a way that somehow benefits the deceiver. More knowledge is desired in the area of purely text-based scenarios. Thirty-seven graduate students at the Air Force Institute of Technology participated in an experiment in order to gain an initial understanding of how people determine whether text has been manipulated, and to identify specific areas that may be more closely investigated in future research. Excerpts were drawn from editions of a current-events newsletter that the participants receive on a weekly basis as part of their enrollment in the graduate program. Some of the excerpts …


Motion Analysis And Segmentation Through Spatio-Temporal Slices Processing, Chong-Wah Ngo, Ting-Chuen Pong, Hong-Jiang Zhang Mar 2003

Motion Analysis And Segmentation Through Spatio-Temporal Slices Processing, Chong-Wah Ngo, Ting-Chuen Pong, Hong-Jiang Zhang

Research Collection School Of Computing and Information Systems

This paper presents new approaches in characterizing and segmenting the content of video. These approaches are developed based upon the pattern analysis of spatio-temporal slices. While traditional approaches to motion sequence analysis tend to formulate computational methodologies on two or three adjacent frames, spatio-temporal slices provide rich visual patterns along a larger temporal scale. In this paper, we first describe a motion computation method based on a structure tensor formulation. This method encodes visual patterns of spatio-temporal slices in a tensor histogram, on one hand, characterizing the temporal changes of motion over time, on the other hand, describing the motion …


Maca-P: A Mac For Concurrent Transmissions In Multi-Hop Wireless Networks, Arup Acharya, Archan Misra, Sorav Bansal Mar 2003

Maca-P: A Mac For Concurrent Transmissions In Multi-Hop Wireless Networks, Arup Acharya, Archan Misra, Sorav Bansal

Research Collection School Of Computing and Information Systems

This paper presents the initial design and performance study of MACA-P, a RTS/CTS based MAC protocol that enables simultaneous transmissions in multihop ad-hoc wireless networks. Providing such low-cost multihop and high performance wireless access networks is an important enabler of pervasive computing. MACA-P is a set of enhancements to the 802.11 DCF that allows parallel transmissions in many situations when two neighboring nodes are either both receivers or both transmitters, but a receiver and a transmitter are not neighbors. Like 802.11, MACA-P contains a contention-based reservation phase prior to data transmission. However, the data transmission is delayed by a control …


Energy-Efficient Broadcast And Multicast Trees For Reliable Wireless Communication, Suman Banerjee, Archan Misra, Jihwang Yeo, Ashok Agrawala Mar 2003

Energy-Efficient Broadcast And Multicast Trees For Reliable Wireless Communication, Suman Banerjee, Archan Misra, Jihwang Yeo, Ashok Agrawala

Research Collection School Of Computing and Information Systems

We define energy-efficient broadband and multicast schemes for reliable communication in multi-hop wireless networks. Unlike previous techniques, the choice of neighbors in the broadband and multicast trees in these schemes, are based not only on the link distance, but also on the error rates associated with the link. Our schemes can be implemented using both positive and negative acknowledgement based reliable broadcast techniques in the link layer. Through simulations, we show that our scheme achieves up to 45% improvement over previous schemes on realistic 100-node network topologies. A positive acknowledgment based implementation is preferred. Our simulations show that the additional …


Health Care Informatics, Keng Siau Mar 2003

Health Care Informatics, Keng Siau

Research Collection School Of Computing and Information Systems

The health care industry is currently experiencing a fundamental change. Health care organizations are reorganizing their processes to reduce costs, be more competitive, and provide better and more personalized customer care. This new business strategy requires health care organizations to implement new technologies, such as Internet applications, enterprise systems, and mobile technologies in order to achieve their desired business changes. This article offers a conceptual model for implementing new information systems, integrating internal data, and linking suppliers and patients.


Stegfs: A Steganographic File System, Hwee Hwa Pang, Kian-Lee Tan, Xuan Zhou Mar 2003

Stegfs: A Steganographic File System, Hwee Hwa Pang, Kian-Lee Tan, Xuan Zhou

Research Collection School Of Computing and Information Systems

While user access control and encryption can protect valuable data from passive observers, those techniques leave visible ciphertexts that are likely to alert an active adversary to the existence of the data, who can then compel an authorized user to disclose it. This paper introduces StegFS, a steganographic file system that aims to overcome that weakness by offering plausible deniability to owners of protected files. StegFS securely hides user-selected files in a file system so that, without the corresponding access keys, an attacker would not be able to deduce their existence, even if the attacker is thoroughly familiar with the …


Flexible And Scalable Public Key Security For Ssh, Yasir Ali Feb 2003

Flexible And Scalable Public Key Security For Ssh, Yasir Ali

Dartmouth College Master’s Theses

A standard tool for secure remote access, the SSH protocol uses public-key cryptography to establish an encrypted and integrity-protected channel with a remote server. However, widely-deployed implementations of the protocol are vulnerable to man-in-the-middle attacks, where an adversary substitutes her public key for the server's. This danger particularly threatens a traveling user Bob borrowing a client machine.

Imposing a traditional X.509 PKI on all SSH servers and clients is neither flexible nor scalable nor (in the foreseeable future) practical. Requiring extensive work or an SSL server at Bob's site is also not practical for many users.

This paper presents our …


Development Of A Systems Engineering Model Of The Chemical Separations Process: Quarterly Progress Report 11/16/02- 2/15/03, Yitung Chen, Randy Clarksean, Darrell Pepper Feb 2003

Development Of A Systems Engineering Model Of The Chemical Separations Process: Quarterly Progress Report 11/16/02- 2/15/03, Yitung Chen, Randy Clarksean, Darrell Pepper

Separations Campaign (TRP)

Two activities are proposed in this Phase I task: the development of a systems engineering model and the refinement of the Argonne code AMUSE (Argonne Model for Universal Solvent Extraction). The detailed systems engineering model is the start of an integrated approach to the analysis of the materials separations associated with the TRP Program. A second portion of the project is to streamline and improve an integral part of the overall systems model, which is the software package AMUSE. AMUSE analyzes the UREX process and other related solvent extraction processes and defines many of the process streams that are integral …


Towards A Performance Model For Special Purpose Orb Middleware, Venkita Subramonian, Guoliang Xing, Christopher Gill, Ron Cytron Feb 2003

Towards A Performance Model For Special Purpose Orb Middleware, Venkita Subramonian, Guoliang Xing, Christopher Gill, Ron Cytron

All Computer Science and Engineering Research

General purpose middleware has been shown effective in meeting diverse functional requirements for a wide range of distributed systems. Advanced middleware projects have also supported single quality-of-service dimensions such as real-time, fault tolerance, or small memory foot-print. However, there is limited experience supporting multiple quality-of-service dimensions in middleware to meet the needs of special purpose applications. Even though general purpose middleware can cover an entire spectrum of functionality by supporting the union of all features required by each application, this approach breaks down for distributed real-time and embedded sys-tems. For example, the breadth of features supported may interfere with small …


Twinscan: A Software Package For Homology-Based Gene Prediction, Paul Flicek Feb 2003

Twinscan: A Software Package For Homology-Based Gene Prediction, Paul Flicek

All Computer Science and Engineering Research

A complete mapping from genome to proteome would constitute a foundation for genome-based biology and provide targets for pharmaceutical and therapeutic intervention. This is one reason gene structure prediction has been a major subfield of computational biology for over 20 years. Many of the widely used gene prediction systems were developed in the 1990s and are unable to take advantage of the revolution in comparative genomics brought on by the sequencing of the entire genomes of an increasing numbers of vertebrates. Twinscan is a new system for high-throughput gene-structure prediction that exploits the patterns of conservation observed in alignments between …


Privacy-Enhanced Credential Services, Alex Iliev, Sean Smith Feb 2003

Privacy-Enhanced Credential Services, Alex Iliev, Sean Smith

Computer Science Technical Reports

The use of credential directories in PKI and authorization systems such as Shibboleth introduces a new privacy risk: an insider at the directory can learn much about otherwise protected interactions by observing who makes queries, and what they ask for. Recent advances in Practical Private Information Retrieval provide promising countermeasures. In this paper, we extend this technology to solve this new privacy problem, and present a design and preliminary prototype for a LDAP-based credential service that can prevent even an insider from learning anything more than the fact a query was made. Our preliminary performance analysis suggests that the complete …


Keyjacking: Risks Of The Current Client-Side Infrastructure, John Marchesini, S W. Smith, Meiyuan Zhao Feb 2003

Keyjacking: Risks Of The Current Client-Side Infrastructure, John Marchesini, S W. Smith, Meiyuan Zhao

Computer Science Technical Reports

In theory, PKI can provide a flexible and strong way to authenticate users in distributed information systems. In practice, much is being invested in realizing this vision via client-side SSL and browser-based keystores. Exploring this vision, we demonstrate that browsers will use personal certificates to authenticate requests that the person neither knew of nor approved (and which password-based systems would have defeated), and we demonstrate the easy permeability of these keystores (including new attacks on medium and high-security IE/XP keys). We suggest some countermeasures, but also suggest that a fundamental rethinking of the trust, usage, and storage model might result …


Tcp Over Wireless Links: Mechanisms And Implications, Sonia Fahmy, Venkatesh Prabhakar, Srinivas R. Avasarafa, Ossama M. Younis Feb 2003

Tcp Over Wireless Links: Mechanisms And Implications, Sonia Fahmy, Venkatesh Prabhakar, Srinivas R. Avasarafa, Ossama M. Younis

Department of Computer Science Technical Reports

No abstract provided.


Handgrip Pattern Recognition, Zong Chen Jan 2003

Handgrip Pattern Recognition, Zong Chen

Dissertations

There are numerous tragic gun deaths each year. Making handguns safer by personalizing them could prevent most such tragedies. Personalized handguns, also called "smart" guns, are handguns that can only be fired by the authorized user. Handgrip pattern recognition holds great promise in the development of the smart gun.

Two algorithms, static analysis algorithm and dynamic analysis algorithm, were developed to find the patterns of a person about how to grasp a handgun. The static analysis algorithm measured 160 subjects' fingertip placements on the replica gun handle. The cluster analysis and discriminant analysis were applied to these fingertip placements, and …


A Method For Developing In-Silico Protein Homologs, Susan Mcclatchy Jan 2003

A Method For Developing In-Silico Protein Homologs, Susan Mcclatchy

Theses

Computational methods for identifying and screening the most promising drug receptor candidates in the human genome are of great interest to drug discovery researchers. Successful methods will accurately identify and narrow the field of potential drug receptor candidates. This study details one such method.

The method described here begins with the assumption that novel drug receptors have high sequence similarity to established drug receptors. The similarity search program FASTA3 aligns translated sequences of the human genome to known drug receptor sequences and ranks these alignments by measuring their statistical significance. Query results returned by FASTA3 are assembled into "in-silico proteins" …


Analysis Of Gene Expression Data Using Expressionist 3.1 And Genespring 4.2, Indu Shrivastava Jan 2003

Analysis Of Gene Expression Data Using Expressionist 3.1 And Genespring 4.2, Indu Shrivastava

Theses

The purpose of this study was to determine the differences in the gene expression analysis methods of two data mining tools, ExpressionisticTM 3.1 and GeneSpringTM 4.2 with focus on basic statistical analysis and clustering algorithms. The data for this analysis was derived from the hybridization of Rattus norvegicus RNA to the Affymetrix RG34A GeneChip. This analysis was derived from experiments designed to identify changes in gene expression patterns that were induced in vivo by an experimental treatment.

The tools were found to be comparable with respect to the list of statistically significant genes that were up-regulated by more …


Storage Allocation In Bounded Time, Sharath Reddy Cholleti Jan 2003

Storage Allocation In Bounded Time, Sharath Reddy Cholleti

All Computer Science and Engineering Research

The correctness of a real-time system is very much dependent on the time at which a specific task is completed. Hence, satisfying a storage allocation request within bounded time is important. Fragmentation of the heap after repeated allocations and deallocations is a major issue for real-time systems, as most allocators depend on garbage collection for defragmentation of the heap, which might not finish in time to honor deadlines. We present the storage requirement for a defragmentation-free binary-buddy allocator. We also study a localized defragmentation algorithm to satisfy a single allocation request, within bounded time, instead of requiring defragmentation of the …


The Design And Performance Of Special Purpose Middleware: A Sensor Networks Case Study, Venkita Subramonian, Guoliang Xing, Christopher Gill, Ron Cytron Jan 2003

The Design And Performance Of Special Purpose Middleware: A Sensor Networks Case Study, Venkita Subramonian, Guoliang Xing, Christopher Gill, Ron Cytron

All Computer Science and Engineering Research

General purpose middleware has been shown to be effective in meeting diverse functional requirements for a wide range of distributed systems. Advanced middleware projects have also supported a single quality-of-service dimension such as real-time, fault tolerance, or small memory footprint. However, there is limited experience supporting multiple quality-of-service dimensions in mid-dleware to meet the needs of special purpose applications. Even though general purpose middleware can cover an entire spectrum of applications by supporting the union of all features required by each application, this approach breaks down for distributed real-time and embedded systems. In particular, features from one dimension such as …


3d-Structural Homology Detection Via Unassigned Residual Dipolar Couplings, Christopher James Langmead, Bruce Randall Donald Jan 2003

3d-Structural Homology Detection Via Unassigned Residual Dipolar Couplings, Christopher James Langmead, Bruce Randall Donald

Computer Science Technical Reports

Recognition of a protein's fold provides valuable information about its function. While many sequence-based homology prediction methods exist, an important challenge remains: two highly dissimilar sequences can have similar folds --- how can we detect this rapidly, in the context of structural genomics? High-throughput NMR experiments, coupled with novel algorithms for data analysis, can address this challenge. We report an automated procedure for detecting 3D-structural homologies from sparse, unassigned protein NMR data. Our method identifies the 3D-structural models in a protein structural database whose geometries best fit the unassigned experimental NMR data. It does not use sequence information and is …


On The Nonembeddability And Crossing Numbers Of Some Kleinical Polyhedral Maps On The Torus, Adrian Riskin, Judy L. Klein Jan 2003

On The Nonembeddability And Crossing Numbers Of Some Kleinical Polyhedral Maps On The Torus, Adrian Riskin, Judy L. Klein

Mathematics

We designed and constructed a sundial for the purpose of observing the declination of the sun and thus marking solar seasonal variation. The 122 × 122 cm vertical sundial on the south-facing wall of our library has two unusual features: a nodus on the gnomon that casts a shadow of a point for marking the height of the sun and a large blank working space for students to mark the shadow of the nodus at different hours of the day and to connect the marks of 1 day in a line of declination. We discuss the design of a dial …


Bridging The Ict Gap: A Study Of Uk Online Centres, John Cook, Matt Smith Jan 2003

Bridging The Ict Gap: A Study Of Uk Online Centres, John Cook, Matt Smith

Articles

An initiative to create about 6,000 UK online centres aims to bridge the gap between those in society who have access to and are able to use information and communication technologies competently, and those who do not. UK online centres can be seen as networked community learning entities, playing an expanding role in formal and informal community-based learning.

The study described below provides a detailed snapshot of what was happening in UK online centres in the first nine months of 2002. The goal was to gain an improved understanding of the social context of the centres, and issues around the …


A Transport Framework For Distributed Brokering Systems, Shrideep Pallickara, Geoffrey C. Fox, John Yin, Gurham Gunduz, Hongbin Liu, Ahmet Uyar, Mustafa Varank Jan 2003

A Transport Framework For Distributed Brokering Systems, Shrideep Pallickara, Geoffrey C. Fox, John Yin, Gurham Gunduz, Hongbin Liu, Ahmet Uyar, Mustafa Varank

Electrical Engineering and Computer Science - All Scholarship

Increasingly, services need to interact with a wide spectrum of devices with varying networking capabilities. Services hosted on a messaging infrastructure need to optimally utilize and exploit the conditions that exist within the local networks. The messaging infrastructure must manage the communication between external resources, services and clients to achieve the highest possible system performance and reliability. In this paper we suggest that a transport framework needs to be incorporated into the messaging infrastructure hosting the services. We base our investigations in the context of the NaradaBrokering system.


Tr-2003005: Lambek Calculus Is Np-Complete, Mati Pentus Jan 2003

Tr-2003005: Lambek Calculus Is Np-Complete, Mati Pentus

Computer Science Technical Reports

No abstract provided.


Tr-2003009: A Hierarchical Projection Pursuit Clustering Algorithm, Jayson E. Rome, Alexei D. Miasnikov, Robert M. Haralick Jan 2003

Tr-2003009: A Hierarchical Projection Pursuit Clustering Algorithm, Jayson E. Rome, Alexei D. Miasnikov, Robert M. Haralick

Computer Science Technical Reports

No abstract provided.


Tr-2003004: Superfast Algorithms For Singular Toeplitz/Hankel-Like Matrices, Victor Y. Pan Jan 2003

Tr-2003004: Superfast Algorithms For Singular Toeplitz/Hankel-Like Matrices, Victor Y. Pan

Computer Science Technical Reports

No abstract provided.


The Computational Complexity Of Motion Planning, Jeff R.K. Hartline '01, Ran Libeskind-Hadas Jan 2003

The Computational Complexity Of Motion Planning, Jeff R.K. Hartline '01, Ran Libeskind-Hadas

All HMC Faculty Publications and Research

In this paper we show that a generalization of a popular motion planning puzzle called Lunar Lockout is computationally intractable. In particular, we show that the problem is PSPACE-complete. We begin with a review of NP-completeness and polynomial-time reductions, introduce the class PSPACE, and motivate the significance of PSPACE-complete problems. Afterwards, we prove that determining whether a given instance of a generalized Lunar Lockout puzzle is solvable is PSPACE-complete.