Computer Sciences Commons^™

Project Isaac: Building Simulations For Virtual Environments, George Vanĕček, James Cremer

Department of Computer Science Technical Reports

No abstract provided.

Dealing With Mobility: Issues And Research Challenges, Evaggelia Pitoura, Bharat Bhargava

Department of Computer Science Technical Reports

No abstract provided.

The Design And Implementation Of Tripwire: A File System Integrity Checker, Gene H. Kim, Eugene H. Spafford

Department of Computer Science Technical Reports

No abstract provided.

Query Optimization And Processing In Federated Database Systems, Ee Peng Lim, Jaideep Srivastava

Research Collection School Of Computing and Information Systems

No abstract provided.

An Adaptive Coding Scheme With Code Combining For Mobile Radio Systems, Robert H. Deng, Huafei Zhou

Research Collection School Of Computing and Information Systems

The authors propose and study an adaptive error-control coding scheme for binary digital FM (BFM) mobile radio transmission. The scheme employs code combining through packet retransmissions. The number of transmissions of a packet is in proportion to the channel fading/noise levels, which is in contrast to time diversity techniques where a fixed number of repetitions of a data packet is performed even in the absence of channel errors. Furthermore, the receiver uses received signal envelopes as channel state information, which significantly improves the throughput and bit error rate (BER) performance. Performance of the proposed scheme is analyzed for frequency-flat Rayleigh …

Multiple Query Optimization With Depth-First Branch-And-Bound, Ahmet Cosar, Ee Peng Lim, Jaideep Srivastava

Research Collection School Of Computing and Information Systems

In certain database applications such as deductive databases, batch query processing, and recursive query processing etc., a single query can be transformed into a set ofclosely related database queries. Great benefits can be obtained by executing a group of related queries all together in a single unijied multi-plan instead of executing each query separately. In order to achieve this, Multiple Query Optimization (MQO) identifies common task(s) (e.g. common subezpressions, joins, etc.) among a set of query plans and creates a single unified plan (multiplan) which can be executed to obtain the required outputs forall queries at once. In this paper, …

Methodology For Modeling High Performance Distributed And Parallel Systems, Rakesh Kushwaha

Dissertations

Performance modeling of distributed and parallel systems is of considerable importance to the high performance computing community. To achieve high performance, proper task or process assignment and data or file allocation among processing sites is essential. This dissertation describes an elegant approach to model distributed and parallel systems, which combines the optimal static solutions for data allocation with dynamic policies for task assignment. A performance-efficient system model is developed using analytical tools and techniques.

The system model is accomplished in three steps. First, the basic client-server model which allows only data transfer is evaluated. A prediction and evaluation method is …

A Comprehensive Part Model And Graphical Schema Representation For Object-Oriented Databases, Michael H. Halper

Dissertations

Part-whole modeling plays an important role in the development of database schemata in data-intensive application domains such as manufacturing, design, computer graphics. text document processing, and so on. Object-oriented databases (OODBs) have been targeted for use in such areas. Thus, it is essential that OODBs incorporate a part relationship as one of their modeling primitives. In this dissertation, we present a comprehensive OODB part model which expands the boundaries of OODB part-whole modeling along three fronts. First, it identifies and codifies new semantics for the OODB part relationship. Second, it provides two novel realizations for part relationships and their associated …

Morphological Operations In Image Processing And Analysis, Chamim Christopher Pu

Dissertations

Morphological operations applied in image processing and analysis are becoming increasingly important in today's technology. Morphological operations which are based on set theory, can extract object features by suitable shape (structuring elements). Morphological filters are combinations of morphological operations that transform an image into a quantitative description of its geometrical structure which based on structuring elements. Important applications of morphological operations are shape description, shape recognition, nonlinear filtering, industrial parts inspection, and medical image processing.

In this dissertation, basic morphological operations are reviewed, algorithms and theorems are presented for solving problems in distance transformation, skeletonization, recognition, and nonlinear filtering. A …

Medium Access Control Mechanisms For High Speed Metropolitan Area Networks, Michail Papamichail

Dissertations

In this dissertation novel Medium Access Control mechanisms for High Speed Metropolitan Area networks are proposed and their performance is investigated under the presence of single and multiple priority classes of traffic. The proposed mechanisms are based on the Distributed Queue Dual Bus network, which has been adopted by the IEEE standardization committee as the 802.6 standard for Metropolitan Area Networks, and address most of its performance limitations. First, the Rotating Slot Generator scheme is introduced which uses the looped bus architecture that has been proposed for the 802.6 network. According to this scheme the responsibility for generating slots moves …

Characterization Of Three-Dimensional Shear Flows, Kurra Bhaswan

Theses

This work investigates techniques to analyze and characterize the presence of microstructure in moderately dilute three-dimensional shear flows. In three dimensional shear flows, a distinct structure develops as the coefficient of restitution is lowered with the particles exhibiting a strong tendency towards the formation of clusters. There exists a need to automatically detect and characterize this microstructure in the given flow. Several methods are examined for effective characterization of the microstructure. The techniques employed are based on the classification of the data based on the properties of the Voronoi diagram constructed from the positional parameters of the two-dimensional slices of …

Using Temporal Subsumption For Developing Efficient Error-Detecting Distributed Algorithms, Martina Schollmeyer, Bruce M. Mcmillin

Computer Science Technical Reports

Distributed algorithms can use executable assertions derived from program verification to detect errors at run-time. However, a complete verification proof outline contains a large number of assertions, and embedding all of them into the program to be checked at run-time would make error-detection very inefficient.

The technique of temporal subsumption examines the dependencies between the individual assertions along program execution paths. In contrast to classical subsumption, where all logical expressions to be examined are true simultaneously, an assertion need only be true when the corresponding statement in the distributed program has been executed. Thus, temporal subsumption based on the set …

A Run-Time Decision Procedure For Responsive Computing Systems, Grace Tsai, Matt Insall, Bruce M. Mcmillin

Computer Science Technical Reports

A responsive computing system is a hybrid of real-time, distributed and fault-tolerant systems. In such a system, severe consequences will occur if the logical and physical specifications of the system are not met. In this paper, we present a logic, Interval Temporal Logic (ITL), to specify responsive systems and give decision procedures to verify properties of the system at run-time as follows. First, we collect, during execution, events occurring in the system to represent a distributed computation. Next, we specify properties of the system using ITL formulas. Finally, we apply the decision procedures to determine satisfaction of the formulas. Thus, …

Establishing A Distributed Processing And Distributed Database Environment For Intergraph Mge & Orscle Products, Praveen Chandrasekhar

Electronic Dissertations and Theses

The department of Agricultural Economics undertake various government contracts for GIS based applications. Currently, they have multi-year contracts with the Louisiana Department of Health and Hospitals (LDHH). This contract is carried out in the Agricultural Economics Geographical Information System lab (AEGIS). One part of the contract is to integrate a heterogenous system comprising of PCs and Intergraph workstations so that the PC can share the data or Microstation Geographical information system Environment (MGE) and ORACLE based applications. Since the Department also undertakes other contracts which requires them to use ARC/INFOR as the front-end while the data would reside in ORACLE …

Parametricity And Local Variables, Peter W. O'Hearn, R. D. Tennent

Electrical Engineering and Computer Science - Technical Reports

We propose that the phenomenon of local state may be understood in terms of Strachey's concept of parametric (i.e., uniform) polymorphism. The intuitive basis for our proposal is the following analogy: a non-local procedure is independent of locally-declared variables in the same way that a parametrically polymorphic function is independent of types to which it is instantiated. A connection between parametricity and representational abstraction was first suggested by J. C. Reynolds. Reynolds used logical relations to formalize this connection in languages with type variables and user-defined types. We use relational parametricity to construct a model for an Algol-like language in …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 9, Number 8, October 1993, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

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

Semantics-Based Information Brokering: A Step Towards Realizing The Infocosm, Vipul Kashyap, Amit P. Sheth

Kno.e.sis Publications

The rapid advances in computer and communication technologies, and their merger, is leading to a global information market place. It will consist of federations of very large number of information systems that will cooperate to varying extents to support the users' information needs. We propose an architecture which may facilitate meeting these needs. It consists of three main components: information providers, information brokers and information consumers. We also propose an approach to information brokering. We discuss two of it's tasks: information resource discovery, which identities relevant information sources for a given query, and query processing, which involves the generation of …

Cyclo-Static Scheduling Of Large Grain Dataflow Algorithms On A Local Area Atamm Multicomputing Testbed, Sudeepto Roy

Electrical & Computer Engineering Theses & Dissertations

A strategy for cyclo-statically scheduling deterministic large grain dataflow (LGDF) algorithms for distributed execution on loosely coupled multicomputer architectures is presented in this research. The computational paradigm used is the ODU/NASA developed Algorithm To Architecture Mapping Model (ATAMM), which consists of marked graphs and Gantt chart representations that model the iterative execution of deterministic LGDF algorithms for different values of throughput and computation time. It is postulated that the behavior of these algorithms could be represented by the aggregate execution of an ensemble of cyclically shifted threads of a specific node sequence. Assuming the existence of one or more such …

Mobile-Process Based Distributed Memory Simulations, Janche Sang, Edward Mascarenhas, Vernon J. Rego

Department of Computer Science Technical Reports

No abstract provided.

Scheduling With Compensation In Multi- Database Systems, Aidong Zhang, Bharat Bhargava

Department of Computer Science Technical Reports

No abstract provided.

A Characterization Of Connecting Maps As Nonlinear Roots Of The Identity, J. Peters

Department of Computer Science Technical Reports

No abstract provided.

Efficient Implementation Of Thread Migration On Distributed-Memory Multi-Processors, Janche Sang, Vernon J. Rego

Department of Computer Science Technical Reports

No abstract provided.

Visualizing Object Oriented Software In Three Dimensions, Colin Ware, David Hui, Glenn Franck

Center for Coastal and Ocean Mapping

There is increasing evidence that it is possible to perceive and understand increasingly comple x information systems if they are displayed a s graphical objects in a three dimensional space . Object-oriented software provides an interestin g test case - there is a natural mapping fro m software objects to visual objects . In this paper we explore two areas. 1) Information perception : we are running controlled experiments to determine empirically if our initial premise is valid; how much more (or less) can be understoo d in 3D than in 2D? 2) Layout: our strategy is to combine partially …

Comparative Study Of Louville And Symplectic Integrators, Daniel I. Okunbor

Computer Science Technical Reports

In this paper, we construct an integrator that conserves volume in phase space. We compare the results obtained using this method and a symplectic integrator. The results of our experiments do not reveal any superiority of the symplectic over strictly volume-preserving integrators. We also investigate the effect of numerically conserving energy in a numerical process by rescaling velocities to keep energy constant at every step. Our results for Henon-Heiles problem show that keeping energy constant in this way destroys ergodicity and forces the solution onto a periodic orbit.

Constructing An Interval Temporal Logic For Real-Time Systems, Grace Tsai, Matt Insall, Bruce M. Mcmillin

Computer Science Technical Reports

A real-time system is one that involves control of one or more physical devices with essential timing requirements. Examples of these systems are command and control systems, process control systems, flight control systems, and the space shuttle avionics systems. The characteristics of these systems are that severe consequences will occur if the logical and physical timing specifications of the systems are not met.

Formal specification and verification are among the techniques to achieve reliable software for real-time systems, in which testing may be impossible or too dangerous to perform. This paper presents a modal logic, Interval Temporal , built upon …

Structured And Object-Oriented Methodologies: A Comparative Analysis Based On A Case Study, Gary Brian Warren

Honors Capstone Projects and Theses

No abstract provided.

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 9, Number 7, September 1993, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

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

Wavelet Localization Of The Radon Transform, Tim Olson, Joe Destefano

Computer Science Technical Reports

In this paper we develop an algorithm which significantly reduces radiation exposure in x-ray tomography, when a local region of the body is to be imaged. The algorithm uses the properties of wavelets to essentially localize the Radon transform. The algorithm differs from previous algorithms for doing local tomography because it recovers an approximation to the original image, not the image modulo the nullspace of the local tomography operator, or the Lambda transform of the image. This is possible because we do not truly invert the interior Radon transform, but rather sample the Radon transform sparsely away from the local …

Modeling Flexibility In Distributed Transactions, Ahmed Elmagarmid, Aidong Zhang

Department of Computer Science Technical Reports

No abstract provided.

Softlab - A Virtual Laboratory For Computational Science, Christoph M. Hoffmann, Elias N. Houstis, John R. Rice, Ann Christine Catlin, Margaret Gaitatzes, N-H. Linda Wang, Christos G. Takoudis, David G. Taylor

Department of Computer Science Technical Reports

No abstract provided.