Digital Commons Network^™

A Concurrency Control Algorithm For An Open And Safe Nested Transaction Model, Sanjay Kumar Madria

Computer Science Faculty Research & Creative Works

We present a concurrency control algorithm for an open and safe nested transaction model. We use prewrite operations in our model to increase the concurrency. Prewrite operations are modeled as subtransactions in the nested transaction tree. The subtransaction which initiates prewrite subtransactions are modelled as recovery point subtransaction. The recovery point subtransaction can release their locks before its ancestors commit. Thus, our model increases the concurrency in comparison to other nested transaction models. Our model is useful an environment of long-running transactions common in object oriented databases, computer aided design and in the software development process

Rmesh Algorithms For Parallel String Matching, Hsi-Chieh Lee, Fikret Erçal

Computer Science Faculty Research & Creative Works

String matching problem received much attention over the years due to its importance in various applications such as text/file comparison, DNA sequencing, search engines, and spelling correction. Especially with the introduction of search engines dealing with tremendous amount of textual information presented on the world wide web and the research on DNA sequencing, this problem deserves special attention and any algorithmic or hardware improvements to speed up the process will benefit these important applications. In this paper, we present three algorithms for string matching on reconfigurable mesh architectures. Given a text T of length n and a pattern P of …

The Effects Of Human-Computer Communication Mode, Task Complexity, And Desire For Control On Performance And Discourse Organization In An Adaptive Task, Cristina Bubb-Lewis

Psychology Theses & Dissertations

The present study examined how different communication patterns affected task performance with an adaptive interface. A Wizard-of-Oz simulation (Gould, Conti, & Hovanyecz, 1983) was used to create the impression of a talking and listening computer that acted as a teammate to help participants interact with a computer application.

Four levels of communication mode were used which differed in the level of restriction placed on human-computer communication. In addition, participants completed two sets of tasks (simple and complex). Further, a personality trait, Desire for Control (DC), was measured and participants were split into high and low groups for analysis. Dependent measures …

Operation And Control In A Competitive Market: Distributed Generation In A Restructured Industry, Judith Cardell, Richard Tabors

Engineering: Faculty Publications

The prospect of independent ownership for distributed technologies is being encouraged by the current deregulation of the industry, and it is possible that the new generators will be independently operated as well as independently owned. The siting of numerous small-scale generators in distribution feeders is likely to have an impact on the operations and control of the power system, a system designed to operate with large, central generating facilities. In response to the new and potentially conflicting economic and technical demands of a growing number of independent players, the power system may require new means for coordinating system operations. Price …

High-Order Object Model Based Software Analysis, Xiaoqing Frank Liu, Hungwen Lin

Computer Science Faculty Research & Creative Works

The integration of object oriented modeling and structured analysis (SA) for developing a well structured object oriented software system is a challenge for requirements analysts and software designers. Some of the existing object oriented modeling techniques adopt approaches that are very different from SA, and others have clumsily stayed with SA after a few modifications. Our High Order Object Modeling Technique (HOOMT) however, attempts to strike a mean between both extremes while at the same time provides an effective modeling method. HOOMT consists of two models, the High Order Object Model and the Object Information Flow Model. By using the …

Time-Optimal Tree Computations On Sparse Meshes, D. Bhagavathi, V. Bokka, H. Gurla, S. Olariu, J. L. Schwing

Computer Science Faculty Publications

The main goal of this work is to fathom the suitability of the mesh with multiple broadcasting architecture (MMB) for some tree-related computations. We view our contribution at two levels: on the one hand, we exhibit time lower bounds for a number of tree-related problems on the MMB. On the other hand, we show that these lower bounds are tight by exhibiting time-optimal tree algorithms on the MMB. Specifically, we show that the task of encoding and/or decoding n-node binary and ordered trees cannot be solved faster than Ω(log n) time even if the MMB has an infinite …

Webassess, Justin Anthony Brown

Theses : Honours

This project and research has resulted in the development of a World Wide Web (WWW) based testing system. WEBassess can be accessed and used from any point in the world that has a connection to the WWW. The WEBassess system allows for the creation and completion of tests through the WWW interface. Scoring and feedback of submitted tests is completely automated, allowing students to see their test result immediately, including visual indicators for correct and incorrect answers. These test results may then be viewed by academic staff, showing complete test details, such as unit code, test title, score, percentage, date …

Does Good Project Management Ensure Successful Software Development?, Julie Lisa Eldridge

Theses : Honours

For many years the development of computer software has been plagued by poor customer satisfaction caused by missed schedules, underestimated budgets and the development of products which do not meet requirements. The ever increasing reliance on computers, as reported by Sommerville ''the result of the proliferation of computer systems into all aspects of life and business is that personal, corporate, national and international economies are [becoming] increasingly dependant on computers and software systems" ( 1992, p.2), calls for more stable software which can be developed within time and budget constraints. To achieve this, software development activities must be analysed and …

Lyceum: A Multi-Protocol Digital Library Gateway, Ming-Hokng Maa, Michael L. Nelson, Sandra L. Esler

Computer Science Faculty Publications

Lyceum is a prototype scalable query gateway that provides a logically central interface to multi-protocol and physically distributed, digital libraries of scientific and technical information. Lyceum processes queries to multiple syntactically distinct search engines used by various distributed information servers from a single logically central interface without modification of the remote search engines. A working prototype (http://www.larc.nasa.gov/lyceum/) demonstrates the capabilities, potentials, and advantages of this type of meta-search engine by providing access to over 50 servers covering over 20 disciplines.

Microlanguages For Operating System Specialization, Calton Pu, Andrew P. Black, Crispin Cowan, Jonathan Walpole, Charles Consel

Computer Science Faculty Publications and Presentations

Specialization is a technique that has the potential to provide operating system clients with the performance and functionality that they need, while still retaining the advantages of a simple generic code base for the operating system maintainer. However, at present the specialization process is labor-intensive and requires the knowledge of an expert in the domain of application behavior. In order to realize the full advantages of specialization, we believe that the process must be automated. This means building tools for specialization, and also making the domain knowledge explicit in some form or other. A specialization toolkit has been developed jointly …

A Migratable User-Level Process Package For Pvm, Ravi Kunuru, Steve Otto, Jonathan Walpole

Computer Science Faculty Publications and Presentations

Shared, multi-user, workstation networks are characterized by unpredictable variability in system load. Further, the concept of workstation ownership is typically present. For efficient and unobtrusive computing in such environments, applications must not only overlap their computation with communication but also redistribute their computations adaptively based on changes in workstation availability and load. Managing these issues at application level leads to programs that are difficult to write and debug. In this paper, we present a system that manages this dynamic multi-processor environment while exporting a simple message-based programming model of a dedicated, distributed memory multiprocessor to applications. Programmers are thus insulated …

Curriculum Development And Evaluation For A Computer Literacy Course, Molly J. Fagan

Dissertations and Theses @ UNI

This paper describes a curriculum that was developed and used for a computer literacy course at the University of Northern Iowa. The curriculum included a unit of computer programming, which has not been included as part of the computer literacy course in recent years at the University of Northern Iowa. Surveys were given at the beginning of the semester to determine the approximate level of students' prior knowledge. The same survey was given at the end of the semester and the results of both were compared to see how much more comfortable each individual student felt using the various computer …

Minimizing The Number Of Optical Amplifiers Needed To Support A Multi-Wavelength Optical Lan/Man, Byrav Ramamurthy, Jason Iness, Biswanath Mukherjee

School of Computing: Conference and Workshop Papers

Optical networks based on passive star couplers and employing wavelength-division multiplexing (WDhf) have been proposed for deployment in local and metropolitan areas. Amplifiers are required in such networks to compensate for the power losses due to splitting and attenuation. However, an optical amplifier has constraints on the maximum gain and the maximum output power it can supply; thus optical amplifier placement becomes a challenging problem. The general problem of minimizing the total amplifier count, subject to the device constraints, is a mixed-integer non-linear problem. Previous studies have attacked the amplifier placement problem by adding the “artificial” constraint that all wavelengths, …

Physical Media Independence: System Support For Dynamically Available Network Interfaces, Jon Inouye, Jim Binkley, Jonathan Walpole

Computer Science Faculty Publications and Presentations

Advances in hardware technology has fueled the proliferation of dynamically configurable network interface cards. This empowers mobile laptop users to select the most appropriate interface for their current environment. Unfortunately, the majority of system software remains "customized" for a particular network configuration, and assumes many network characteristics remain invariant over the runtime of the software. Physical Media Independence (PMI) is the concept of making assumptions about a particular device explicit, detecting events which invalidate these assumptions, and recovering once events are detected. This paper presents a model supporting PMI. Based on device availablilty, the model identifies implicit device-related assumptions made …

Integrated Queries To Existing Bibliographic And Structured Databases, Ee Peng Lim, Ying Lu

Research Collection School Of Computing and Information Systems

It is widely accepted that future digital library applications have to be built upon different kinds of database servers to draw upon different forms of data, including bibliographic, text, multimedia, and structured data. In this paper, the problem of integrating existing public bibliographic databases and structured databases which reside at different locations in the network is addressed. Although bibliographic data is semistructured, its attribute set is often determined by an international standard known as MARC. To unify bibliographic and structured data, the well-known SQL was extended to model bibliographic related attributes and queries. In particular, a new data type was …

A Hypermedia Database To Manage World-Wide-Web Documents, Schubert Shou Boon Foo, Ee Peng Lim

Research Collection School Of Computing and Information Systems

The surge of interest in the World-Wide-Web (WWW) with its potential commercial payoff has resulted in an explosion of information as organisations join in to publish and do business on the Internet. A related development, Intranet, which basically uses the same technology to build private corporate WWW-based networks, has emerged to provide cost-effective and efficient groupware and information management solutions for organisations. As a result, the Hyper Text Markup Language (HTML), used for constructing WWW documents, has become a contender for authoring future office documents. With this scenario, this study examines WWW practices and highlights the inadequacy and drawbacks of …

Managing World Wide Web Publications, Schubert Foo, Ee Peng Lim

Research Collection School Of Computing and Information Systems

The surge of interest in the World Wide Web (WWW), with its potential commercial payoff, has resulted in an explosion of information as organizations join in the fray to publish and do business on the Internet. In addition, Intranet, the private corporate WWW‐based network, has also emerged to provide cost‐effective and efficient groupware and information management solutions for organizations. As a result, the HyperText Markup Language used for constructing WWW documents has become a contender for authoring future office documents. Examines the current practices of WWW publishing and highlights its inadequacies and drawbacks. Demonstrates the need and advantages of using …

An Efficient Algorithm For Direct Computation Of Adjacent Block Coefficients In The Transformed Domain, Chaman Sabharwal, Brian Quandt

Computer Science Faculty Research & Creative Works

The current research in many areas of image processing involves operations performed in the compressed domain [Smith and Rowe 1993, Chang 93]. Compressed domain may be DCT, Wavelet, JPEG or MPEG etc. The algorithms for .these transformations may be used for information filtering such as feature extraction and edge detection. The image transformations such as compositing, occluding, and scaling may also be performed in the compressed domain. It is desirable to perform these operations on compressed data directly because the smaller size of data involves less computational complexity. The computation in the compressed domain eliminates the overhead of decoding the …

Randomised Shuffle And Applied Misinformation: An Enhanced Model For Contact-Based Smart-Card Serial Data Transfer, Michael Collins

Theses: Doctorates and Masters

Contact-based smart-cards, which comply to the International Standard IS0-7816, communicate with their associated read/write machines via a single bi-directional serial link. This link is easy to monitor with inexpensive equipment and resources, enabling captured data to be removed for later examination. In many contact-based smart-cards the logical abilities are provided by eight-bit microcontroller units (MCU) which are slow at performing effective cryptographic functions. Consequently, for expediency, much data may be transferred in plain-text across the vulnerable communications link, further easing an eavesdropper's task. Practitioners in military communications protect transmitted information by varying a link's carrier frequency in an apparently random …

Student Modeling In An Intelligent Tutoring System, Jeremy E. Thompson

Theses and Dissertations

This thesis explores a new approach to modeling the student in an intelligent tutoring system (ITS), by providing a student model which learns new solutions from the student. A prototype of the new approach to ITS is demonstrated in the Euclidean geometry domain. Complete C++, CLIPS, and Tcl/Tk code listings are included in the appendices for reference. Adaptable multiple software agents were targeted for implementation, based on current literature. However, the student model is found to be maintainable without multiple software agents, while still allowing for tracking several possible solution paths when monitoring student solutions. This capability contradicts previous research …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 12, Number 10, December 1996, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

A twelve page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

Algorithms For Adapting Materialised Views In Data Warehouses, Mukesh Mohania, Guozhu Dong

Kno.e.sis Publications

In this paper we consider the problem of materialised view adaptation in data warehouses. Materialised views are important in data warehousing where they are used to speed up query processing on large amounts of data. User requirements change over time, which may change the definitions of views dynamically. For such situations, the question arises whether the materialised views should be recomputed from scratch for every change in the definition or they should be obtained by adapting old materialised views. Changes to a view definition may be expensive, if the view is recomputed from scratch. Therefore, it is worthwhile to examine …

Reverse Engineering Of Computer-Based Navy Systems, Lonnie R. Welch, Guohui Yu, Binoy Ravindran, Franz J. Kurfess, Jorge Henriques, Mark Wilson, Antonio L. Samuel, Michael W. Masters

Computer Science and Software Engineering

The financial pressure to meet the need for change in computer-based systems through evolution rather than through revolution has spawned the discipline of reengineering. One driving factor of reengineering is that it is increasingly becoming the case that enhanced requirements placed on computer-based systems are overstressing the processing resources of the systems. Thus, the distribution of processing load over highly parallel and distributed hardware architectures has become part of the reengineering process for computer-based Navy systems.

This paper presents an intermediate representation (IR) for capturing features of computer-based systems to enable reengineering for concurrency. A novel feature of the IR …

An Efficient Collective Communication Library For Pvm, Chirapol Mathawaphan

Masters Theses

PVM enables the use of network of workstations for parallel and distributed computation. PVM provides the message-passing primitives which include those for point-to-point communication and collective communications. The current approaches for the collective communication operations in PVM use algorithms that do not exhibit good performance.

In this thesis, we develop new approaches to improve the performance of collective communication operations in PVM by using shared memory with IP broadcasting and IP multicasting mechanism. We have implemented these approaches and have run extensive tests. This report shows the comparison of the time used by current approaches and our approaches.

Export Database Derivation Approach For Supporting Object-Oriented Wrapper Queries, Ee Peng Lim, Hon-Kuan Lee

Research Collection School Of Computing and Information Systems

Wrappers export the schema and data of existing heterogeneous databases and support queries on them. In the context of cooperative information systems, we present a flexible approach to specify the derivation of object-oriented (OO) export databases from local relational databases. Our export database derivation consists of a set of extent derivation structures (EDS) which defines the extent and deep extent of export classes. Having well-defined semantics, the EDS can be readily used in transforming wrapper queries to local queries. Based on the EDS, we developed a wrapper query evaluation strategy which handles OO queries on the export databases. The strategy …

Algebraic Algorithm Design And Local Search, Robert P. Graham Jr.

Theses and Dissertations

Formal, mathematically-based techniques promise to play an expanding role in the development and maintenance of the software on which our technological society depends. Algebraic techniques have been applied successfully to algorithm synthesis by the use of algorithm theories and design tactics, an approach pioneered in the Kestrel Interactive Development System (KIDS). An algorithm theory formally characterizes the essential components of a family of algorithms. A design tactic is a specialized procedure for recognizing in a problem specification the structures identified in an algorithm theory and then synthesizing a program. Design tactics are hard to write, however, and much of the …

Requirements, Design, And Development Of A Rapidly Reconfigurable, Photo-Realistic, Virtual Cockpit Prototype, Terry A. Adams

Theses and Dissertations

The United States Air Force uses aircraft flight simulators for pilot training and mission rehearsal. They use a variety of simulators for this task ranging with prices ranging from $400,000 to $30,000,000. These simulators have specialized hardware that restricts reuse of their components and increases maintenance costs. Air Education and Training Command wants to reduce simulators cost and improve availability to the operational commands by supporting research in virtual reality flight simulators. This thesis looks at the development of a reconfigurable virtual cockpit in a distributed virtual environment that can be used for different aircraft as well as training scenarios. …

A Domain Independent Framework For Developing Knowledge Based Computer Generated Forces, James L. Benslay Jr.

Theses and Dissertations

Computer Generated Forces (CGFs) are important players in Distributed Interactive Simulation (DIS) exercises. A problem with CGFs is that they do not exhibit sufficient human behaviors to make their use effective. The SOAR approach has yielded a human cognitive model that can be applied to CGFs, but this is extremely complex. The product of the research reported in this thesis is a much less complex behavioral framework for a CGF that is easy to validate, revise, and maintain. To support this, an existing, domain independent CGF architecture is discussed and applied to an experimental CGF. Techniques for modeling the knowledge …

Utilizing Bayesian Techniques For User Interface Intelligence, Robert A. Harrington

Theses and Dissertations

The purpose of this research is to study the injection of an intelligent agent into modern user interface technology. This agent is intended to manage the complex interactions between the software system and the user, thus making the complexities transparent to the user. The background study will show that while interesting and promising research exists in the domain of intelligent interface agents, very little research has been published that indicates true success in representing the uncertainty involved in predicting user intent. The interface agent architecture presented in this thesis will offer one solution for solving the problem using a newly …

Simulation Based Performance Evaluation Of Resource Allocation Algorithms For Implementation In The Shf-Dama Satellite Network, Eric P. Hobson

Theses and Dissertations

Sponsored by DISA, the SHF-DAMA Standard addresses the warfighter's requirements for flexible, reliable, and efficient (technically and fiscally) satellite communications. The Standard proposes a system supporting both packet data transfer and single-channel-per-carrier voice and data circuits assigned on a demand basis. The Standard does not address management of the DSCS 3 transponder's bandwidth and power resources among priority classes of users. This effort characterizes the SHF-DAMA system's performance over each combination of the following resource management algorithm features: (1) preemption enabled and disabled; (2) using the Standard-specified collision resolution technique and a binary exponential backoff; (3) using complete partitioning, complete …