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Computer Science Faculty Research & Creative Works

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Full-Text Articles in Computer Sciences

Adaptive Information Filtering: Improvement Of The Matching Technique And Derivation Of The Evolutionary Algorithm, Daniel R. Tauritz, Ida G. Sprinkhuizen-Kuyper Jan 1999

Adaptive Information Filtering: Improvement Of The Matching Technique And Derivation Of The Evolutionary Algorithm, Daniel R. Tauritz, Ida G. Sprinkhuizen-Kuyper

Computer Science Faculty Research & Creative Works

Adaptive Information Filtering is concerned with filtering information streams in changing environments. The changes may occur both on the transmission side (the nature of the streams can change) and on the reception side (the interests of a user can change). The research described in this report details the progress made in a prototype Adaptive Information Filtering system based on weighted trigram analysis and evolutionary computation. The main improvements of the algorithms employed by the system concern the computation of the distance between weighted trigram vectors and a further analysis of the two-pool evolutionary algorithm. We tested our new prototype system …


Automated Highway Systems, Bruce M. Mcmillin, Kristen L. Sanford Oct 1998

Automated Highway Systems, Bruce M. Mcmillin, Kristen L. Sanford

Computer Science Faculty Research & Creative Works

Intelligent transportation systems (ATS) have received much attention in the transportation community and by the government in the past decade. The technology is an extension of intelligent vehicle highway systems to include transportation modes beyond highways. Major elements of ITS include: advanced traffic management systems; advanced traveller information systems; automated highway systems; the Intelligent Vehicle Initiative; and advanced commercial vehicle systems. ITS initiatives are proposed for both urban and rural areas to increase transportation system capacity by more fully utilizing the existing transportation system and improve transportation system safety. The feasibility of realizing a fully automated highway system is discussed.


Fuzzy Requirements, Xiaoqing Frank Liu Apr 1998

Fuzzy Requirements, Xiaoqing Frank Liu

Computer Science Faculty Research & Creative Works

Requirement analysis and specification is the first major step in software development. The goal is to develop a requirements specification that contains all the customers' true needs. The analysis describes quality requirements and their constraints, such as cost and resources. Functional requirements are analyzed in terms of inputs, outputs and their relationships. Hence, requirements analysis enables software engineers to specify software function and establish software design and implementation constraints. The paper discusses the specification of individual fuzzy requirements using fuzzy sets.


Parallel Genetic Algorithm To Solve The Satisfiability Problem, Nicole Nemer-Preece, Ralph W. Wilkerson Feb 1998

Parallel Genetic Algorithm To Solve The Satisfiability Problem, Nicole Nemer-Preece, Ralph W. Wilkerson

Computer Science Faculty Research & Creative Works

This Paper Offers a Parallel Genetic Algorithm Solution to the Satisfiability Problem. It Combines Components of the Davis-Putnam Method and Genetic Algorithms for the Solution. This Solution is Useful in the Areas of Theorem Proving, Constraint Satisfaction Programming, and VLSI Design. the Algorithm is Implemented and Run on a Paragon. the Results Show Performance Improvement by Increasing the Number of Nodes. Two Parallel Methods Are Compared: One that Implements Interprocessor Communication and One that Does Not. the Results Show Performance Improvement with the Method that Uses Interprocessor Communication.


Systolic Algorithm For Processing Rle Images, Hao Feng, Fikret Erçal, Filiz Bunyak Jan 1998

Systolic Algorithm For Processing Rle Images, Hao Feng, Fikret Erçal, Filiz Bunyak

Computer Science Faculty Research & Creative Works

Image difference operation is commonly used in on-line automated printed circuit board (PCB) inspection systems as well as many other image processing applications. In this paper, we describe a new systolic algorithm and its system architecture which computes image differences in run-length encoded (RLE) format. The efficiency of this operation greatly affects the overall performance of the inspection system. It is shown that, for images with a high similarity measure, the time complexity of the systolic algorithm is a small constant. A formal proof of correctness for the algorithm is also given in the paper.


Segmentation Of Printed Circuit Board Images Into Basic Patterns, Madhav Moganti, Fikret Ercal Jan 1998

Segmentation Of Printed Circuit Board Images Into Basic Patterns, Madhav Moganti, Fikret Ercal

Computer Science Faculty Research & Creative Works

Segmentation is the first and foremost step in the inspection of the printed circuit boards. In this paper a new technique for the segmentation of printed circuit board (PCB) images is presented. The technique basically segments a given PCB into small windows containing primitive PCB subpatterns. The technique proposed exploits the simplicity and the homogeneity of the PCB images and is inherently parallel. A detailed discussion of the experiments and the results obtained is also presented. © 1993 Academic Press.


Java, Java, Java, Chaman Sabharwal Jan 1998

Java, Java, Java, Chaman Sabharwal

Computer Science Faculty Research & Creative Works

Everyone is talking about Java. The driving force for this chatter is Java''s simplicity and potential power. Java is programming language, and a language for the intranet and the World Wide Web (WWW). Java is a Write On one platform and Run on Many platforms (WORM) language. For network-friendly, platform-independent applications, Java (originally Oak) is an object oriented programming language. Java source code is compiled into a virtual machine code or bytecode. This makes the Java platform independent. It can be placed on a Web site, and executed on the client side on a PC-Intel, Mac, Motorola or UNIX-Solaris machine …


A Transaction Model For Mobile Computing, Sanjay Kumar Madria, Bharat Bhargava Jan 1998

A Transaction Model For Mobile Computing, Sanjay Kumar Madria, Bharat Bhargava

Computer Science Faculty Research & Creative Works

We introduce a prewrite operation before a write operation in a mobile transaction to improve data availability. A prewrite operation does not update the state of a data object but only makes visible the value that the data object will have after the commit of the transaction. Once the transaction has read all the values and declares all the prewrites, it can precommit at a mobile host. The remaining transaction's execution is shifted to the stationary host. Writes on a database consume both time and resources at the stationary host and are therefore delayed. A pre-committed transaction's prewrite values are …


Data Mining, Yongjian Fu Oct 1997

Data Mining, Yongjian Fu

Computer Science Faculty Research & Creative Works

Data mining is the process of identifying interesting patterns from large databases. It is the core part of the knowledge discovery in database (KDD) process. Tasks in data mining are classified into summarization, classification, clustering, association and trend analysis. Data mining techniques are adopted from many research areas including statistics, machine learning, database systems, neural networks, rough sets and visualization. The techniques have been applied successfully in many areas from business to science to sports.


Information Retrieval On The World Wide Web, Venkat N. Gudivada, Vijay V. Raghavan, William I. Grosky, Rajesh Kasanagottu Sep 1997

Information Retrieval On The World Wide Web, Venkat N. Gudivada, Vijay V. Raghavan, William I. Grosky, Rajesh Kasanagottu

Computer Science Faculty Research & Creative Works

Effective search and retrieval are enabling technologies for realizing the full potential of the Web. The authors examine relevant issues, including methods for representing document content. They also compare available search tools and suggest methods for improving retrieval effectiveness.


Time-Efficient Maze Routing Algorithms On Reconfigurable Mesh Architectures, Fikret Ercal, H. C. Lee Aug 1997

Time-Efficient Maze Routing Algorithms On Reconfigurable Mesh Architectures, Fikret Ercal, H. C. Lee

Computer Science Faculty Research & Creative Works

The routing problem is one of the most widely studied problems in VLSI design. Maze-routing algorithms are used in VLSI routing and robot path planning. Efficiency of the parallel maze routing algorithms which were mostly based on C. Y. Lee's algorithm8is poor. In this paper, we propose time-efficient algorithms to solve the maze-routing problem on a reconfigurable mesh architecture. The constant-time algorithms presented include: (i) testing the existence of specific types of paths between two terminals, and (ii) finding an absolute shortest path (ASP) and a shortest duplex-path (SDP). In addition, a fast algorithm to find the single shortest path …


An Introduction To Algorithmic Information Theory: Its History And Some Examples, George Markowsky Mar 1997

An Introduction To Algorithmic Information Theory: Its History And Some Examples, George Markowsky

Computer Science Faculty Research & Creative Works

The goal of this paper is to provide a simple introduction to Algorithmic Information Theory (AIT) that will highlight some of the main ideas without presenting too many details. More technical treatments of these ideas can be found in References [1], [2], [3] and [4], which are listed at the end of the paper. The main ideas of Algorithmic Information Theory will be presented using English as the underlying programming language. The presentation illustrates the fact that the same arguments can be expressed in any other reasonable language and that the main results have a robust universality across all reasonable …


Rmesh Algorithms For Parallel String Matching, Hsi-Chieh Lee, Fikret Erçal Jan 1997

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 …


High-Order Object Model Based Software Analysis, Xiaoqing Frank Liu, Hungwen Lin Jan 1997

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 …


Keyboardless Visual Programming Using Voice, Handwriting, And Gesture, Jennifer Leopold, A. Ambler Jan 1997

Keyboardless Visual Programming Using Voice, Handwriting, And Gesture, Jennifer Leopold, A. Ambler

Computer Science Faculty Research & Creative Works

Visual programming languages have facilitated the application development process, improving our ability to express programs, as well as our ability to view, edit and interact with them. Yet even in programming environments, productivity is restricted by the primary input sources: the mouse and the keyboard. As an alternative, we investigate a program development interface which responds to the most natural human communication technologies: voice, handwriting and gesture. Speech- and pen-based systems have yet to find broad acceptance in everyday life because they are insufficiently advantageous to overcome problems with reliability. However, we believe that a visual programming environment with a …


An Efficient Algorithm For Direct Computation Of Adjacent Block Coefficients In The Transformed Domain, Chaman Sabharwal, Brian Quandt Jan 1997

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 …


Direct Finite First-Order Model Generation With Negative Constraint Propagation Heuristic, Olga Shumsky, Ralph W. Wilkerson, Fikret Ercal, William W. Mccune Jan 1997

Direct Finite First-Order Model Generation With Negative Constraint Propagation Heuristic, Olga Shumsky, Ralph W. Wilkerson, Fikret Ercal, William W. Mccune

Computer Science Faculty Research & Creative Works

An Automated Finite First-Order Model Generator Has Been Developed. the Problem is Viewed as a First-Order Satisfiability Problem. Most Existing Model Generators Reduce the Problem to Propositional Satisfiability by Converting the Input First-Order Clauses into Propositional Clauses. This Generator, Unlike Others, Stores the Input First-Order Clauses and Solves the Problem Directly. It Uses an Exhaustive Backtracking Algorithm with Weight-Based Splitting. a Negative Constraint Propagation is Implemented to Reduce the Number of Decision Points and Thus to Speed Up the Search. © 1997 ACM.


User Defined Prewrites For Increasing Concurrency In Design Databases, Sanjay Kumar Madria, A. Embong Jan 1997

User Defined Prewrites For Increasing Concurrency In Design Databases, Sanjay Kumar Madria, A. Embong

Computer Science Faculty Research & Creative Works

We introduce a prewrite operation before a write operation is performed on design databases, a database that consists of objects as engineering designs. A prewrite operation does not actually make a design but it only makes available the model of the design that the transaction will produce in future. Once the prewrite design by a transaction is announced, the transaction executes a pre-commit operation. After the pre-commit, read operations can access the prewrite design even before the pre-committed transaction has finally made the design and committed. Therefore, our algorithm increases the potential concurrency as compared to the algorithms that permit …


Evolutionary Computation Applied To Adaptive Information Filtering, Daniel R. Tauritz, Ida G. Sprinkhuizen-Kuyper, Joost N. Kok Jan 1997

Evolutionary Computation Applied To Adaptive Information Filtering, Daniel R. Tauritz, Ida G. Sprinkhuizen-Kuyper, Joost N. Kok

Computer Science Faculty Research & Creative Works

Information Filtering is concerned with filtering data streams in such a way as to leave only pertinent data (information) to be perused. When the data streams are produced in a changing environment the filtering has to adapt too in order to remain effective. Adaptive Information Filtering is concerned with filtering in changing environments. The changes may occur both on the transmission side (the nature of the streams can change), and on the reception side (the interest of a user can change). Weighted trigram analysis is a quick and flexible technique for describing the contents of a document. A novel application …


A Fast Algorithm For Complete Subcube Recognition, Fikret Erçal, H. J. Burch Jan 1997

A Fast Algorithm For Complete Subcube Recognition, Fikret Erçal, H. J. Burch

Computer Science Faculty Research & Creative Works

The complete subcube recognition problem is defined as, given a collection of available processors on an n-dimensional hypercube, locate a subcube of dimension k that consists entirely of available processors, if one exists. Despite many algorithms proposed so far on this subject, improving the time complexity of this problem remains a challenge. Efficiency limits that can be reached have not been exhausted yet. This paper proposes a novel algorithm to recognize all the overlapping subcubes available on an n-dimensional hypercube whose processors are partially allocated. Given P=2n, as the total number of processors in the hypercube, the new algorithm runs …


A Concurrency Control Algorithm For An Open And Safe Nested Transaction Model, Sanjay Kumar Madria Jan 1997

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


Timestamp-Based Approach For The Detection And Resolution Of Mutual Conflicts In Distributed Systems, Sanjay Kumar Madria Jan 1997

Timestamp-Based Approach For The Detection And Resolution Of Mutual Conflicts In Distributed Systems, Sanjay Kumar Madria

Computer Science Faculty Research & Creative Works

We present a timestamp based algorithm for the detection of both write-write and read-write conflicts for a single file in distributed systems during network partitions. Our algorithm allows operations to occur in different network partitions simultaneously. When the sites from different partitions merge, the algorithm detects and resolves both read-write and write-write conflicts without taking into account the semantics of the transactions. Once the conflicts have been detected some reconciliation steps for the resolution of conflicts have also been proposed. Our algorithm will be useful in real-time systems where timeliness of operations is more important than response time (delayed commit)


Run-Time Security Evaluation: Can We Afford It?, Cristina Serban, Bruce M. Mcmillin Sep 1996

Run-Time Security Evaluation: Can We Afford It?, Cristina Serban, Bruce M. Mcmillin

Computer Science Faculty Research & Creative Works

The use of the run-time security evaluation (RTSE) method for a distributed application takes a toll in overall application performance. The associated overhead and its major sources are discussed, along with possible solutions for improvements, and questions that remain still open.


R-By-C Crozzle: An Np-Hard Problem, Michelle Gower, Ralph W. Wilkerson Feb 1996

R-By-C Crozzle: An Np-Hard Problem, Michelle Gower, Ralph W. Wilkerson

Computer Science Faculty Research & Creative Works

In an Australian Magazine, a Monetary Prize is Awarded to the Person with the Best Answer to a Word Puzzle Called a Crozzle. the Placement of Words into a Ten by Fifteen Grid Obtaining the Highest Score is the Best Answer. Various Search Techniques Have Been Employed to Solve This Problem, Yet No One Has Shown Whether There is a Polynomial-Time Algorithm to Find the Best Crozzle. This Paper Creates a Similar Word Puzzle, Called R-By-C Crozzle, by Lifting the Constraint on the Grid Size. R-By-C Crozzle is Not in NP, But There Exists a Polynomial Reduction to It from …


Near Perfect Hash Table For Image Databases, Sanjiv K. Bhatia, Chaman Sabharwal Feb 1996

Near Perfect Hash Table For Image Databases, Sanjiv K. Bhatia, Chaman Sabharwal

Computer Science Faculty Research & Creative Works

In image database systems, a perfect hash table can be used to enhance the efficiency and effectiveness of the image retrieval process. In our earlier work, we have proposed heuristic algorithms to compute the minimal perfect hash table from symbolic picture objects. The hash table thus computed cannot be modified easily, limiting its application to fixed databases like the ones on CD-ROMs. In this paper, we propose a new data structure to allow for insertion and deletion in the hash table. The new data structure, the near-perfect hash table, allows a limited number of collisions on some of the hash …


Data Parallel Implementation Of Surface-To-Surface Intersection, Terence M. Burke, Chaman Sabharwal Feb 1996

Data Parallel Implementation Of Surface-To-Surface Intersection, Terence M. Burke, Chaman Sabharwal

Computer Science Faculty Research & Creative Works

The sequential surface-to-surface intersection algorithm has been extensively studied in the past decade. With the advent of parallel processing machines, it is desirable to parallelize this algorithm to gain extra computation speed for real time applications. An earlier attempt to parallelize this algorithm was on shared memory parallel computer due to the highly shared model of data structure [Chang 1991). A shared memory machine is not available at every location. Instead, we have implemented it on distributed parallel computer iPSC/860 with 32 processors. The initial development was done using PVM software in heterogeneous environment consisting of Sun workstations and 486's …


Optimization Of The Discriminatory Power Of A Trigram Based Document Clustering Algorithm Using Evolutionary Computation, Daniel R. Tauritz Jan 1996

Optimization Of The Discriminatory Power Of A Trigram Based Document Clustering Algorithm Using Evolutionary Computation, Daniel R. Tauritz

Computer Science Faculty Research & Creative Works

No abstract provided.


Frequency Coordination Between Adjacent Carriers Of Two Cdma Operators, Seung Jong Park, Hun Bum Ha, Jong Tai Chung, Yoon Sub Shim, Do Young Lee Jan 1996

Frequency Coordination Between Adjacent Carriers Of Two Cdma Operators, Seung Jong Park, Hun Bum Ha, Jong Tai Chung, Yoon Sub Shim, Do Young Lee

Computer Science Faculty Research & Creative Works

Frequency coordination is the process that assigns frequency bands to neighboring or coexisting systems to minimize interference. This interference is caused by unwanted signals from adjacent frequency bands. Especially, interference is maximized by the spatial near-far problem which occurs in case two different cellular systems serve. This critical case happens when different cellular operators using the adjacent carriers do not collocate their base stations (BS). In this paper, we investigate the frequency coordination when two CDMA operators using adjacent CDMA carriers don't collocate their BS. In order to lessen the unwanted interference, we put the guard band which separates adjacent …


A Systematic Tradeoff Methodology For Acquiring And Validating Imprecise Requirements, J. Yen, Xiaoqing Frank Liu, W. A. Tiao Jan 1996

A Systematic Tradeoff Methodology For Acquiring And Validating Imprecise Requirements, J. Yen, Xiaoqing Frank Liu, W. A. Tiao

Computer Science Faculty Research & Creative Works

Requirement analysis is one of the most important phases in a software development process. Existing requirement methodologies are limited in specifying requirements that are usually vague and imprecise, and in supporting tradeoff analysis between the conflicting requirements. In this paper, the elasticity of imprecise requirements is captured using fuzzy logic to facilitate tradeoffs between conflicting requirements. Based on the marginal rate of substitution in decision science, we have developed a systematic approach to elicit the structures and the parameters of imprecise requirements, to validate the scheme for aggregating requirements, and to assess relative priorities of conflicting requirements.


Adaptive Information Filtering As A Means To Overcome Information Overload, Daniel R. Tauritz Jan 1996

Adaptive Information Filtering As A Means To Overcome Information Overload, Daniel R. Tauritz

Computer Science Faculty Research & Creative Works

Information Filtering is concerned with filtering data streams in such a way as to leave only pertinent data (information) to be perused. When the data streams are produced in a changing environment (as most if not all are) the filtering has to adapt too in order to remain effective. Adaptive Information Filtering (AIF) is concerned with filtering in changing environments. The changes may occur both on the transmission side (the nature of the streams can change), and on the reception side (the interest of a user can change). The thesis research described in this paper combines trigram analysis, clustering, and …