Computer Engineering Commons^™

Infrared Ellpsometer/ Polarmeter System, Method Of Calibration, And Use Thereof, Daniel W. Thompson, Blaine D. Johs

Department of Electrical and Computer Engineering: Faculty Publications

A sample system investigation system, such as an ellipsometer or polarimeter system, for use in investigating sample systems with electromagnetic wavelengths in the infrared range, and a calibration method for compensating nonidealities in multi-dimensional system rotated and non-rotated component representing matricies, are disclosed. An essentially achromatic compensator of dual-rhomb construction, which introduces a (3*LAMBDA/4) phase shift, but essentially no deviation in the direction of propagation of a polarized beam of electromagnetic wavelengths caused to pass there through, even when said compensator is caused to continuously rotate, is also disclosed.

A Modification Of Sugeno Integral Describes Stability And Smoothness Of Fuzzy Control, Hung T. Nguyen, Vladik Kreinovich

Departmental Technical Reports (CS)

Sugeno integral was invented a few decades ago as a natural fuzzy analogue of the classical integral. Sugeno integral has many interesting applications. It is reasonable to expect that it can be used in all application areas where classical integrals are used, and in many such areas it is indeed useful. Surprisingly, however, it has never been used in fuzzy control, although in traditional control, classical integral is one of the main tools.

In this paper, we show that the appropriately modified Sugeno integral is indeed useful for fuzzy control: namely, it provides numerical characterization of stability and smoothness of …

Where To Bisect A Box? A Theoretical Explanation Of The Experimental Results, Vladik Kreinovich, R. Baker Kearfott

Departmental Technical Reports (CS)

No abstract provided.

Ordinal Explanation Of The Periodic System Of Chemical Elements, Eric R. Scerri, Vladik Kreinovich, Piotr Wojciechowski, Ronald R. Yager

Departmental Technical Reports (CS)

Textbooks often claim that quantum mechanics explained the periodic system: namely, the actual configuration of electronic orbits that is responsible for the element's chemical properties can be described as the one that minimizes the total energy, and the energy of each configuration can be computed by using quantum mechanics.

However, a careful analysis of this explanation reveals that, in addition to the basic equations of quantum mechanics, we need some heuristic rules that do not directly follow from quantum physics. One reason why additional heuristics are necessary is that the corresponding numerical equations are extremely difficult to solve, and as …

On Geometry Of Radio Antenna Placements, Olga Kosheleva, Vladik Kreinovich, Andrei M. Finkelstein, Steve Chan

Departmental Technical Reports (CS)

No abstract provided.

Stackguard: Automatic Adaptive Detection And Prevention Of Buffer-Overflow Attacks, Crispin Cowan, Calton Pu, David Maier, Heather Hinton, Jonathan Walpole, Peat Bakke, Steve Beattie, Aaron Grier, Perry Wagle, Qian Zhang

Computer Science Faculty Publications and Presentations

This paper presents a systematic solution to the persistent problem of buffer overflow attacks. Buffer overflow attacks gained notoriety in 1988 as part of the Morris Worm incident on the Internet. While it is fairly simple to fix individual buffer overflow vulnerabilities, buffer overflow attacks continue to this day. Hundreds of attacks have been discovered, and while most of the obvious vulnerabilities have now been patched, more sophisticated buffer overflow attacks continue to emerge.

We describe StackGuard: a simple compiler technique that virtually eliminates buffer overflow vulnerabilities with only modest performance penalties. Privileged programs that are recompiled with the StackGuard …

Attitude Measurement, Mark A. Stedham, Partha P. Banerjee, Seiji Nishifuji, Shogo Tanaka

Electrical and Computer Engineering Faculty Publications

In many practical situations, it is important to determine and measure the attitude of a particular vehicle, such as a ship, an airplane, a piece of mechanical equipment such as a, crane lifter, or a spacecraft. For this reason, many attitude sensors have been developed with advanced computer and semiconductor technologies. This section first introduces the various attitude sensors with an explanation of their operating principles and then presents several methodologies for attitude measurement and determination, including ships and crane lifters, aircraft, and spacecraft applications.

Strategies For Evaluating Software Usability, Ronan Fitzpatrick

Articles

This paper presents a usage analysis and taxonomy of methods which are used to evaluate the usability of computer systems. To accommodate the analysis and taxonomy, a matrix of strategies which can be used for effective usability evaluation is presented. Such an analysis, taxonomy and strategies support human-computer interaction (HCI) professionals who have the responsibility for ensuring computer system usability. The strategies outlined are named Virtual Engineering, Soft Modelling, Hard Review and Real World. This paper also uses a composite set of existing popular generic evaluation methods which can be used as part of these strategies. The methods used are …

Functional Radionuclide Imaging Algorithm Based On The Appended Curve Deconvolution Technique And Its Use In The Diagnosis Of Renovascular Hypertension, İrfan Karagöz, Hi̇kmet Bayhan

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, a new method called the pixel basis functional radionuclide imaging (PBFRI) algorithm based on the appended curve deconvolution technique, in order to be able to increase the medical diagnostic capability of a conventional gamma camera, is presented together with the clinical results. In the PBFRI method, retention function of each pixel is obtained from the renograms and cardiac curves generated by processing the filtered segments of the kidney and heart, using a special deconvolution method. The deconvolution operation is done by using the Fourier transform technique. High frequency artifacts presented by the Fourier transform are removed by …

Genetic Approach For The Determination Of Object Parameters From X Ray Projections, Tayfun Günel, Sedef Kent

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, a new method is presented, based on genetic algorithms for determining object parameters such as radii and/or attenuation coefficients with some assumptions and estimating a cross-sectional image of an object from its projections obtained by X ray illumination. After it was tested for projections degraded by different random noise levels, it was observed that the genetic and fuzzy genetic algorithms improved the signal to noise ratio of the projections. The fuzzy genetic algorithm gave better results than the genetic algorithm.

Modeling Mobile Ip In Mobile Unity, 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 notation and proof logic for specifying and reasoning about mobile systems. In this paper it is argued that Mobile UNITY contributes to the modular development of system specifications because of the declarative fashion in which coordination among components is specified. The packet …

A Simplified Reservation And State Setup Protocol, Hari Adiseshu, Guru Parulkar, Subhash Suri

All Computer Science and Engineering Research

The last few years have seen the development of a model for Integrated Services Internet, which extends the traditional Internet by adding multiple service classes in addition to the traditional best effort service class, and a signaling protocol called RSVP for applications to reserve resources. While this framework has been standardized in the IETF WGs and the RSVP protocol has been defined, there has been no movement towards a commercial implementation of this framework, principally due to its perceived complexity and lack of scalability. This paper analyzes RSVP, discusses some of the its bottlenecks and shows how they can be …

Tcp/Ip Implementation With Endsystem Qos, Sherlia Y. Shi, Gurudatta M. Parulkar, R. Gopalakrishnan

All Computer Science and Engineering Research

This paper presents a Real-time Upcall (RTU) [1] based TCP/IP implementation that guarantees throughput for continuous media applications and ensures low latency bounds for interactive applications. RTU is an endsystem rate-based scheduling mechanism that provides quality of service (QoS) in terms of CPU cycles, to applications. We restructured the existing NetBSD TCP/IP implementation to exploit the RTU concurrency model and to provide predictable performance. Our experimental results show that on two 200 MHz NetBSD PCs connected by a 155Mbps ATM link, the RTU based kernel TCP/IP implementation provides excellent throughput guarantees for periodic connections regardless the system or network load. …

Application Development And Management In The Programmers' Playground, T. Paul Mccartney, E.F. Berkley Shands, Kenneth J. Goldman, William M. Shapiro

All Computer Science and Engineering Research

Application management refers to the process of making software applications available to end-users and providing automated mechanisms for launching and joining such applications. The Programmers' Playground is a computing environment for creating distributed applications from modular, reusable components. This paper discusses a set of tools that enable application developers to: (1) design and debug Playground distributed applications from existing "off-the-shelf" components using a visual configuration tool, (2) make new application components available on the Internet through a "launcher" service, and (3) make complete distributed applications available via a World Wide Web interface, enabling end-users to launch and join the applications …

Terabit Burst Switching Progress Report (6/98-9/98), Jonathan S. Turner

All Computer Science and Engineering Research

This report summarizes progress on the Terabit Burst Switching Project at Washington University for the period from June 15, 1998 through September 15, 1998.

Agnostic Learning Of Geometric Patterns, Sally A. Goldman, Stephen S. Kwek, Stephen D. Scott

All Computer Science and Engineering Research

Goldberg, Goldman, and Scott demonstrated how the problem of recognizing a landmark from a one-dimensional visual image can be mapped to that of learning a one-dimensional geometric pattern and gave a PAC algorithm to learn that class. In this paper, we present an efficient on-line agnostic learning algorithm for learning the class of constant-dimension geometric patterns. Our algorithm can tolerate both classification and attribute noise. By working in higher dimensional spaces we can represent more features from the visual image in the geometric pattern. Our mapping of the data to a geometric pattern, and hence our learning algorithm, is applicable …

Fault-Tolerant Mobile Ip, Rajib Ghosh, George Varghese

All Computer Science and Engineering Research

We describe mechanisms to enhance the reliability and performance of Mobile IP. In Mobile IP today home agents and foreign agents are single points of failure and potential performance bottlenecks. For example, a home agent crash can lead to communication failure if the mobile is away from home. In this paper we describe new mechanisms to allow redundant home and foreign agents. Redundant agents can take over from each other in case of failure, and also split load amongst themselves. Our mechanisms are simple, transparent to existing mobile nodes, and compatible with the existing Mobile IP specification. We have implemented …

On-Line Scheduling With Hard Deadlines, Sally A. Goldman, Jyoti Parwatikar, Subhash Suri

All Computer Science and Engineering Research

We study non-preemptive, online admission control in the hard deadline model: each job must be either serviced prior to its deadline, or be rejected. Our setting consists of a single resource that services an online sequence of jobs; each job has a length indicating the length of time for which it needs the resource, and a delay indicating the maximum time it can wait for the service to be started. The goal is to maximize total resource utilization. The jobs are non-preemptive and exclusive, meaning once a job begins, it runs to completion, and at most one job can use …

Learning From Examples With Unspecified Attribute Values, Sally A. Goldman, Stephen S. Kwek, Stephen D. Scott

All Computer Science and Engineering Research

We introduce the UAV learning model in which some of the attributes in the examples are unspecified. In our model, an example x is classified positive (resp., negative) if all possible assignments for the unspecified attributes result in a positive (resp., negative) classification. Otherwise the classificatoin given to x is "?" (for unknown). Given an example x in which some attributes are unspecified, the oracle UAV-MQ responds with the classification of x. Given a hypothesis h, the oracle UAV-EQ returns an example x (that could have unspecified attributes) for which h(x) is incorrect. We show that any class learnable in …

Diagnostic Screening Of Digital Mammograms Using Wavelets And Neural Networks To Extract Structure, Barry L. Kalman, Stan C. Kwasny, William R. Reinus

All Computer Science and Engineering Research

As the primary tool for detecting breast carcinoma, mammography provides visual images from which a trained radiologist can identify suspicious areas that suggest the presence of cancer. We describe an approach to image processing that reduces an image to a small number of values based on its structural characteristics using wavelets and neural networks. To illustrate its utility, we apply this methodology to the automatic screening of mammograms for mass lesions. Our results approach performance levels of trained human mammographers.

Routing Table Compression Using Binary Tree Collapse, Jonathan Turner, Qiyong Bian, Marcel Waldvogel

All Computer Science and Engineering Research

This paper describes an algorithm which can roughly halve the size of the current Internet routing tables. This algorithm is based on the radix trie representation of routing tables, which was firstly used in the BSD Unix distributions. The binary tree representation, which is a simplified case of radix tree, does well at showing the relationships among all routing table entries and provides us a way to build a collapse algorithm based on its internal structure. The binary tree collapse algorithm consists of three techniques, with the first two quite intuitive while the third is a bit more elaborate. All …

Master Of Science Degree Programs 1998, Nova Southeastern University

College of Engineering and Computing Course Catalogs

No abstract provided.

Router Plugins: A Modular And Extensible Software Framework For Modern High Performance Integrated Services Routers, Dan Decasper, Zubin Dittia, Guru Parulkar, Bernhard Plattner

All Computer Science and Engineering Research

Present day routers typically employ monolithic operating systems which are not easily upgraded and extensible. WIth the rapid rate of protocol development it is becoming increasingly important to dynamically upgrade router software in an incremental fashion. We have designed and implemented a high performance, modular, extended integrated services router software architecture in the NetBSD operating system kernel. This architecture allows code modules, called plugins, to be dynamically added and configured at run time. One of the novel features of our design is the ability to bind different plugins to individual flows; this allows for distinct plugin implementations to seamlessly coexist …

Terabit Burst Switching Progress Report (12/97-2/98), Jonathan S. Turner

All Computer Science and Engineering Research

This report summarizes progress on the Terabit Burst Switching Project at Washington University for the period from December 15, 1997 through March 15, 1998. Efforts during this period have concentrated on working out details of the burst switch architecture, evaluating a variety of implementation alternatives and developing the physical design of the 160 Gb/s ATM switch to allow demonstration of the burst switch within a realistic network context.

Integrating A Constraint Mechanism With The Javabeans Model, William M. Shapiro

All Computer Science and Engineering Research

The JavaBeans component model allows users to plug together software components to create Java applications by specifying simple relationships between component events and properties. This paper describes work on augmenting the simple JavaBeans model with a multi-way constraint mechanism that allows users to graphically specify more complex multi-way contraints, resolve cyclical constraints between bean properties and graphically layout bean components. We also discuss weaknesses in the JavaBeans model and Java Abstract Windowing Toolkit (AWT) that were discovered while integrating a constraint mechanism with JavaBeans.

Lime: Linda Meets Mobility, Gian Pietro Picco, Amy L. Murphy, Gruia-Catalin Roman

All Computer Science and Engineering Research

LIME is a system designed to assist in the rapid development of dependable mobile applications over both wired and ad hoc networks. Mobile agents reside on mobile hosts and all communication takes place via transiently shared tuple spaces distributed across the mobile hosts. The decoupled style of computing characterizing the Linda model is extended to the mobile environment. At the application level, both agents and hosts perceive movement as a sudden change of context. The set of tuples accessible by a particular agent residing on a given host is altered transparently in response to changes in the connectivity pattern among …

Tcp Dynamic Acknowledgment Delay: Theory And Practice, Daniel R. Dooly, Sally A. Goldman, Stephen D. Scott

All Computer Science and Engineering Research

We study an on-line problem that is motivated by the networking problem of dynamically adjusting delays of acknowledgments in the Transmission Control Protocol (TCP). The theoretical problem we study is the following. There is a sequence of n packet arrival times A = and a look-ahead coefficient L. The goal is to partition A into k subsequences sigma1, sigma2, ...,sigmak (where a subsequence end is defined by an acknowledgment) that minimizes a linear combination of the cost for the number of acknowledgments sent and the cost for the additional latency introduced by delaying acknowledgments. At each arrival, an oracle provides …

The Playground Mediator: Visual Tool For Configuring And Debugging Distributed Applications, T. Paul Mccartney

All Computer Science and Engineering Research

The Mediator is a visual configuration tool for use with The Programmers' Playground distributed programming environment. With the Mediator, one can interactively launch distributed application modules, configured communication among the modules, observe communication patterns, interactively control module communication, kill running modules, and receive imported applications from a separate World Wide Web interface. This manual describes how to use the Mediator both as a stand-alone configuration tool and as a visual interface to the Playground Application Management System.

Integrating Security Into The Curriculum, Cynthia E. Irvine, Shiu-Kai Chin, Deborah Frincke

Electrical Engineering and Computer Science - All Scholarship

The number of skilled practitioners of computer security who are able to address the complexities of modern technology and are familiar with successful approaches to system security is very small. People want security but are faced with two difficulties. First, they do not know how to achieve it in the context of their enterprises. They may not even know of a way to translate organizational procedures into policies, much less implement a set of mechanisms to enforce those policies. Second, they have no way of knowing whether their chosen mechanisms are effective. The recent US Presidential Commission on Critical Infrastructure …

Building A Secure Intranet, Fred J. Berryman

Theses

This thesis will explain the vulnerabilities of computers in a networking environment and demonstrate proper procedures for building a secure Intranet.

The Internet is built around the concept of open communication. Data is shared around the globe just as easily as it is from one office or cubical to the next. Corporations are skeptical about putting company data on such a public transport mechanism as the Internet, but the tools used on the Internet are exciting and everyone wants to use them. Out of a desire for the best of both worlds, the Intranet was born.

An intranet that has …