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Computer Engineering Commons

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1996

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Articles 61 - 80 of 80

Full-Text Articles in Computer Engineering

Mobile Unity Coordination Constructs Applied To Packet Forwarding For Mobile Hosts, Peter J. Mccann, Gruia-Catalin Roman Jan 1996

Mobile Unity Coordination Constructs Applied To Packet Forwarding For Mobile Hosts, Peter J. Mccann, Gruia-Catalin Roman

All Computer Science and Engineering Research

With recent advances in wireless communication technology, mobile computing is an increasingly important area of research. A mobile system is one where independently executing components may migrate through some space during the course of the computation, and where the pattern of connectivity among the components changes as they move in and out of proximity. Mobile UNITY is a language and logic for specifying and reasoning about mobile systems, the components of which must operate in a highly decoupled way. In this paper it is argued that Mobile UNITY contributes to the modular development of system specifications because of the declarative …


A Usability Study Of End-User Construction Of Direct Manipulation User Interfaces, T Paul Mccartney Jan 1996

A Usability Study Of End-User Construction Of Direct Manipulation User Interfaces, T Paul Mccartney

All Computer Science and Engineering Research

This paper describes an empirical study of end-users that tested the usability of The Programmers' Playground graphical environment. The Programmers' Playground is a software library and run-time system for constructing distributed multimedia applications. Playground's graphical environment enables end-users to create direct manipulation graphical user interfaces (GUIs) and to dynamically configure communication among distributed application components. In this study, 28 end-users with no prior experience in distributed computing or user interface construction were timed and evaluated on several tasks using our graphical environment. Tasks included the use of direct and indirect constraint relationships, visual configuration of distributed applications, and graphical user …


Building Distributed Applications With Design Patterns, Gruia-Catalin Roman, James C. Hu Jan 1996

Building Distributed Applications With Design Patterns, Gruia-Catalin Roman, James C. Hu

All Computer Science and Engineering Research

Design patterns are a topic of great current interest within the object-oriented programming community. The motivation is both economical and intellectual. On one hand, there is the hope of establishing a common culture and language that fosters communicatino and growth in the software engineering field. While a community dominated by empiricism is seeking to achieve higher levels of formality by capturing its experiences in the form of catalogs of design patterns, another community, deeply rooted in formal thinking, is seeking to make its mark on the every day workings of the software engineering process. Distributed algorithms and the heuristics used …


Ua8 Information Technology Update, Wku Information Technology Jan 1996

Ua8 Information Technology Update, Wku Information Technology

WKU Archives Records

Newsletter created by and about WKU Information Technology.


Analysis Of Mpeg Compressed Video Traffic, Jerome R. Cox Jr., O. Matthew Beal Jan 1996

Analysis Of Mpeg Compressed Video Traffic, Jerome R. Cox Jr., O. Matthew Beal

All Computer Science and Engineering Research

This paper outlines a study of MPEG compressed video sequences and simulation of multiplexed video traffic in the ATM environment. A number of statistical characteristics including autocorrelation and variance of MPEG-1 compressed video sequences are used to characterize the 16 sample traces used in this study. From these measurements, a preliminary model is developed which utilizes basic measurements of the individual component video sequences to predict bandwidth requirements and cell loss of the multiplexed video traffic.


Simulation Of Asynchronous Instruction Pipelines, Chia-Hsing Chien, Mark A. Franklin Jan 1996

Simulation Of Asynchronous Instruction Pipelines, Chia-Hsing Chien, Mark A. Franklin

All Computer Science and Engineering Research

This paper presents the ARAS simulator with which asynchronous instruction pipelines can be modelled, simulated and displayed. ARAS allows one to construct instruction pipelines by preparing various configuration files. Using these files and a number of benchmark programs, performance of the instruction pipelines can be obtained. The performance of asynchronous instruction pipelines can also be compared to synchronous case. Thus, one can decide the optimal design for instruction pipelines in asynchornous or synchronous cases and explore the deisng space of asynchronous instruction pipeline architectures.


On The Performance Of Early Packet Discard, Maurizio Casoni, Jonathan S. Turner Jan 1996

On The Performance Of Early Packet Discard, Maurizio Casoni, Jonathan S. Turner

All Computer Science and Engineering Research

In a previous paper [3], one of the authors, gave a worst-case analysis for the Early Packet Discard (EPD) technique for maintaining packet integrity during overload in ATM switches. This analysis showed that to ensure 100% goodput during overload under worst-case conditions, requires a buffer with enough storage for one maximum length packet from every active virtual circuit. This paper refines that analysis, using assumptions that are closer to what we expect to see in practice and examines how EPD performs when the buffer is not large enough to achieve 100% goodput. We show that 100% goodput can be achieved …


Extending Atm Networks For Efficient Reliable Multicast, Jonathan S. Turner Jan 1996

Extending Atm Networks For Efficient Reliable Multicast, Jonathan S. Turner

All Computer Science and Engineering Research

One of the important features of ATM networks is their ability to support multicast communications. This facilitates the efficient distribution of multimedia information streams (such as audio and video) to large groups of receivers (potentially millions). Because ATM networks do not provide reliable delivery mechanisms, it is up to end systems to provide end-to-end reliability where it is needed. While this is straightforward for point-to-point virtual circuits, it is more difficult for one-to many and many-to-mamy virtual circuits. In this report, we propose some minimal extensions to the hardware of ATM switches that enables end systems to implement reliable multicast …


A Pilot Study Of Speech And Pen User Interface For Graphical Editing, Karl E. Schmidt Jan 1996

A Pilot Study Of Speech And Pen User Interface For Graphical Editing, Karl E. Schmidt

All Computer Science and Engineering Research

As computer size continues to decrease and new user interface technologies become more ubiquitous, the conventional keyboard and mouse input interfaces are becoming harder to design into newer machines and less practical for use in some applications. The pen is one input technology more suited for the upcoming generation of smaller computers using direct manipulation interfaces. However, a pen-only user interface relies on continuous gesture and handwriting tecognizers that are often slow, inaccurate, and error prone for command and text entry. Speech recognition is an input modality that can input commands quickly and potentially be a fast text entry mechanism, …


Mobile Unity: Reasoning And Specification In Mobile Computing, Gruia-Catalin Roman, Peter J. Mccann Jan 1996

Mobile Unity: Reasoning And Specification In Mobile Computing, Gruia-Catalin Roman, Peter J. Mccann

All Computer Science and Engineering Research

Mobile computing represents a major point of departure from the traditional distributed computing paradigm. The potentially very large number of independent computing units, a decoupled computing style, frequent disconnections, continuous position changes, and the location-dependent nature of the behavior and communication patterns present designers with unprecedented challenges in the areas of modularity and dependability. So far, the literature on mobile computing is dominated by concerns having to do with the development of protocols and services. This paper complements this perspective by considering the nature of the underlying formal models that will enable us to specify and reason about such computations. …


Continuous Compilation For Software Development And Mobile Computing, Michael P. Plezbert Jan 1996

Continuous Compilation For Software Development And Mobile Computing, Michael P. Plezbert

All Computer Science and Engineering Research

Software developers typically must choose between interpreted and compiled environments for their programming activities. However, the current trends toward mobile computing and platform independence suggest moving to a new continuous compilation paradigm that integrates the advantages of each environment. Movement in this direction can already be seen in the development of Sun Microsystems' Java environment. The resulting continuous compiler operates not as a prelude to, but rather in tandem with, program execution. In this thesis we present the results of experiments that compare the performance of the continuous compilation model with a more traditional model and show that a performance …


Negotiation As A Resource Allocation Process, Fernando Tohme Jan 1996

Negotiation As A Resource Allocation Process, Fernando Tohme

All Computer Science and Engineering Research

The main economic-theoretic approcahes to the problem of resource allocation make little if any reference to negotiation processes. These processes are fundamentally linguistic, based on the exchange of messages among agents. Communication being so fundamental in the characterization of negotiation processes, the analysis of negotiation must emphasize on the structure of the language in which the negotiations take place. Computer science and particularly Artificial Intelligence have provided interesting insights about that linguistic structure. In the first part of this work we present a brief survey of the literature on resource allocation processes in which communication among agents plays a relevant …


Alchourron's Defeasible Conditionals And Defeasible Reasoning, Fernando Tohme, Ronald P. Loui Jan 1996

Alchourron's Defeasible Conditionals And Defeasible Reasoning, Fernando Tohme, Ronald P. Loui

All Computer Science and Engineering Research

No abstract provided.


The Apic Approach To High Performance Network Interface Design: Protected Dma And Other Techniques, Zubin D. Dittia, Guru M. Parulkar, Jerome R. Cox Jr. Jan 1996

The Apic Approach To High Performance Network Interface Design: Protected Dma And Other Techniques, Zubin D. Dittia, Guru M. Parulkar, Jerome R. Cox Jr.

All Computer Science and Engineering Research

We are building a very high performance 1.2 Gb/s ATM network interface chip called the APIC (ATM Port Interconnect Controller). In addition to borrowing userful ideas from a number of research and commercial prototypes, the APIC design embraces several innovative features, and integrates all of these pieces into a coherent whole. This paper describes some of the novel ideas that have been incorporated in the APIC design with a view to improving the bandwidth and latency seen by end-applications. Among the techniques described, Protected DMA and Protected I/O were designed to allow applications to queue data for transmission or reception …


Supporting Dis Applications Using Atm Multipoint Connection Caching, Anshul Kantawala, Guru Parulkar, John Dehart, Ted Marz Jan 1996

Supporting Dis Applications Using Atm Multipoint Connection Caching, Anshul Kantawala, Guru Parulkar, John Dehart, Ted Marz

All Computer Science and Engineering Research

This report describes an ATM Multipoint Connection Caching strategy (AMCC) to control the explosive growth of traffic within the network and at an endpoint in a large Distributed Interactive Simulation (DIS) application such as a battlefield simulation. For very large DIS applications with 100,000 entities, the current method of broadcasting information among entities will no longer be feasible due to computational and network bandwidth limitations. Our scheme divides the simulation space into grids and each grid square or a set of grid squares forms a multicast group. Entities join the groups within their perception range and thus, they receive state …


Terminal Sliding Mode Control For Rigid Robotic Manipulators With Uncertain Dynamics, Nicola Ritter Jan 1996

Terminal Sliding Mode Control For Rigid Robotic Manipulators With Uncertain Dynamics, Nicola Ritter

Theses: Doctorates and Masters

This thesis presents two new adaptive control laws that use the terminal sliding mode technique for the tracking problem of rigid robotic manipulators with non-linearities, dynamic couplings and uncertain parameters. The first law provides a robust scheme which uses several properties of rigid robotic mauipulators and adaptively adjusts seven uncertain parameter bounds. The law ensures finite time error convergence to the system origin and is simple to implement The second law treats the manipulator as a partially known system. The known dynamics are used to build a nominal control law and the effects of unknown system dynamics arc compensated for …


The Mobile Telephone: The Transportation Of Social Relationships, Kenneth C. Staples Jan 1996

The Mobile Telephone: The Transportation Of Social Relationships, Kenneth C. Staples

Theses: Doctorates and Masters

In the studies of contemporary electronic media artifacts and their effects on society, television, satellites, and computers have been extensively investigated and their various impacts well documented. With regards to telecommunication technologies, academic scholarship is somewhat less, with most comment being restricted to either historic evolution, or technical description. Exceptions to this are, Marvin's reference to the telephone in her publication, When Old Technologies Were New: Thinking About Electronic Communication in the Late Nineteenth Century (1988}, and Umble's The Amish and the telephone: resistance and reconstruction (1992). Both of these publications are used for supporting arguments in my thesis investigating …


Analysis Of Background Noise For Wireless Microwave Lan Channels, Jason C. Hislop Jan 1996

Analysis Of Background Noise For Wireless Microwave Lan Channels, Jason C. Hislop

Theses : Honours

Perusal of the details within, should provide the reader with an insight into general wireless indoor communications within the microwave spectrum, with respect to the problems laced, specific to noise corruption of the transmitted signal. Indoor communication systems are difficult to model, due to the largely random nature of the relevant environment, and the compounding factors that degrade system performance. These factors are many and varied, in accordance with the operational topologies of possible application area. However, there exists a common and increasing need to effectively model the communication links in question. Part of this strategy involves having an understanding …


Simulator For The Performance Analysis Of Cpm Schemes In An Indoor Wireless Environment, Ronald Chua Jan 1996

Simulator For The Performance Analysis Of Cpm Schemes In An Indoor Wireless Environment, Ronald Chua

Theses : Honours

A software simulator for characterising Continuous Phase Modulation (CPM) schemes in an indoor multipath environment has been developed using SIMULINK and MATLAB. The simulator is capable of simulating a wide range of CPM schemes to determine bandwidth efficiency and robustness to additive white Gaussian noise (AWGN) and Rician fading. Initial trials of the simulator indicate that the simulator is functioning correctly. Eventually, the simulator will be used to determine the most suitable modulation scheme for the development of an actual indoor wireless system.


An Application Of Plausible Reasoning To Information Retrieval, Farhad Oroumchian, Robert N. Oddy Dec 1995

An Application Of Plausible Reasoning To Information Retrieval, Farhad Oroumchian, Robert N. Oddy

Farhad Oroumchian

This work explores the use of plausible inferences as a means of retrieving relevant documents. Collins and Michalski’s theory of plausible reasoning has been modified to accommodate information retrieval. Methods are proposed to represent document contents by logical terms and statements, and queries by incomplete logical statements. Extensions to plausible inferences are discussed. Two versions of the extended plausible reasoning system were implemented, one using dominance weights (described in the paper) and the other using tf. Idf (Term Frequency Inverse Document Frequency) weights. Experiments were conducted using the titles and abstracts of the CACM collection and it was found that …