Digital Commons Network^™

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.

Search And Tracking Algorithms For Rapidly Moving Mobiles, Amy L. Murphy, Gruia-Catalin Roman, George Varghese

All Computer Science and Engineering Research

With the advent of wireless technology and laptops, mobility is an important area of research. A fundamental problem in this area is the delivery of messages to a moving mobile. Current solutions work correctly only for slowly moving nodes that stay in one location long enough for tracking to stabilize. In this paper we consider the problem of message delivery to rapidly moving mobile units. With these algorithms, we introduce a new method for designing algorithms based on the paradigm of considering a mobile unit as a message, and adapting traditional message passing algorithms to mobility. Our first algorithm is …

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. …

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 …

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 …

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 …

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.

An Efficient Library For Parallel Ray Tracing And Animation, John Edward Stone

Masters Theses

"A parallel ray tracing library is presented for rendering high detail images of three dimensional geometry and computational fields. The library has been developed for use on distributed memory and shared memory parallel computers and can also run on sequential computers. Parallelism is achieved through the use of message passing and threads. It is shown that the library achieves almost linear scalability when run on large distributed memory parallel computers as well as large shared memory parallel computers.

Several applications of parallel rendering are explored including rendering of CAD models, animation, magnetic resonance imaging, and visualization of volumetric flow fields. …

Language Bindings For A Data-Parallel Runtime, Bryan Carpenter, Geoffrey C. Fox, Donald Leskiw, Xinying Li, Yuhong Wen

Northeast Parallel Architecture Center

The NPAC kernel runtime, developed in the PCRC (Parallel Compiler Runtime Consortium) project, is a runtime library with special support for the High Performance Fortran data model. It provides array descriptors for a generalized class of HPF-like distributed arrays, support for parallel access to their elements, and a rich library of collective communication and arithmetic operations for manipulating these arrays. The library has been successfully used as a component in experimental HPF translation systems. With prospects for early appearance of fully-featured, efficient HPF compilers looking questionable, we discuss a class of more easily implementable data-parallel language extensions that preserve many …

Java/Corba Based Real-Time Infrastructure To Integrate Event-Driven Simulations, Collaboration And Distributed Object/Componentware Computing, Geoffrey C. Fox, Wojtek Furmanski, Hasan T. Ozdemir

Northeast Parallel Architecture Center

We are discussing the four major standard candidates for distributed object/componentware computing: Java, CORBA, COM and WOM within our proposed coordination framework we call Pragmatic Object Web (POW). We describe our integration approach based on multi-protocol middleware server JWORB (Java Web Object Request Broker) that currently integrates HTTP and IIOP and which we now further develop to also support COM and WOM core functionalities. We are also experimenting with visual data ow authoring front-ends using NPAC WebFlow system on top of JWORB based software bus. Finally, we illustrate our technologies in one major application domain- DoD Modeling and Simulation- where …

Towards A Java Environment For Spmd Programming, Bryan Carpenter, Guansong Zhang, Geoffrey C. Fox, Xiaoming Li

Northeast Parallel Architecture Center

As a relatively straightforward object-oriented language, Java is a plausible basis for a scientific parallel programming language. We outline a conservative set of language extensions to support this kind of programming. The programming style advocated is Single Program Multiple Data (SPMD), with parallel arrays added as language primitives. Communications involving distributed arrays are handled through a standard library of collective operations. Because the underlying programming model is SPMD programming, direct calls to other communication packages are also possible from this language.

Considerations In Hpjava Language Design And Implementation, Guansong Zhang, Bryan Carpenter, Geoffrey C. Fox, Xinying Li, Yuhong Wen

Northeast Parallel Architecture Center

This paper discusses some design and implementation issues in the HPJava language. The language is briefly reviewed, then the class library that forms the foundation of the translation scheme is described. Through example codes, we illustrate how HPJava source codes can be translated straightforwardly to ordinary SPMD Java programs calling this library. This is followed by a discussion of the rationale for introducing the language in the first place, and of how various language features have been designed to facilitate efficient implementation.

A Global Communication Optimization Technique Based On Data-Flow Analysis And Linear Algebra, Mahmut Kandemir, P. Banerjee, Alok Choudhary, J. Ramanujam

Electrical Engineering and Computer Science - All Scholarship

Reducing communication overhead is extremely important in distributed-memory message-passing architectures. In this paper, we present a technique to improve communication that considers data access patterns of the entire program. Our approach is based on a combination of traditional data-flow analysis and a linear algebra framework, and works on structured programs with conditional statements and nested loops but without arbitrary goto statements. The distinctive features of the solution are the accuracy in keeping communication set information, support for general alignments and distributions including block-cyclic distributions and the ability to simulate some of the previous approaches with suitable modifications. We also show …

Clouds: A Decision Tree Classifier For Large Datasets, Khaled Alsabti, Sanjay Ranka, Vineet Singh

Electrical Engineering and Computer Science - All Scholarship

Classification for very large datasets has many practical applications in data mining. Techniques such as discretization and dataset sampling can be used to scale up decision tree classifiers to large datasets. Unfortunately, both of these techniques can cause a significant loss in accuracy. We present a novel decision tree classifier called CLOUDS, which samples the splitting points for numeric attributes followed by an estimation step to narrow the search space of the best split. CLOUDS reduces computation and I/O complexity substantially compared to state of the art classifiers, while maintaining the quality of the generated trees in terms of accuracy …

Steady State Memetic Algorithm For Partial Shape Matching, Ender Ozcan, Chilukuri K. Mohan

Electrical Engineering and Computer Science - All Scholarship

Shape matching techniques are important in machine intelligence, especially in applications such as robotics. Currently, there are three major approaches to shape recognition: statistical, syntactic and neural approaches. This paper presents a fourth approach: evolutionary algorithms. A steady state memetic algorithm is shown to be successful in matching shapes even when they are partially obscured, and even in the presence of noise in the input image.

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 …

Secure Delegation For Distributed Object Environments, Nataraj Nagaratnam, Doug Lea

Electrical Engineering and Computer Science - All Scholarship

SDM is a Secure Delegation Model for Java-based distributed object environments. SDM extends current Java security features to support secure remote method invocations that may involve chains of delegated calls across distributed objects. The framework supports a control API for application developers to specify mechanisms and security policies surrounding simple or cascaded delegation. Delegation may also be disabled and optionally revoked. These policies may be controlled explicitly in application code, or implicitly via administrative tools.

Strictly Level-Decreasing Logic Programs, Pascal Hitzler, Anthony K. Seda

Computer Science and Engineering Faculty Publications

We study strictly level-decreasing logic programs (sld-programs) as defined earlier by the present authors. It will be seen that sld-programs, unlike most other classes of logic programs, have both a highly intuitive declarative semantics, given as a unique supported model, and are computationally adequate in the sense that every partial recursive function can be represented by some sld-program P. Allowing for a safe use of cuts, an interpreter based on SLDNF-resolution, as implemented for example in standard Prolog systems, is shown to be sound and complete with respect to this class of programs. Furthermore, we study connections between topological …

Interestingness Of Discovered Association Rules In Terms Of Neighborhood-Based Unexpectedness, Guozhu Dong, Jinyan Li

Kno.e.sis Publications

One of the central problems in knowledge discovery is the development of good measures of interestingness of discovered patterns. With such measures, a user needs to manually examine only the more interesting rules, instead of each of a large number of mined rules. Previous proposals of such measures include rule templates, minimal rule cover, actionability, and unexpectedness in the statistical sense or against user beliefs.

In this paper we will introduce neighborhood-based interestingness by considering unexpectedness in terms of neighborhood-based parameters. We first present some novel notions of distance between rules and of neighborhood of rules. The neighborhood-based interestingness of …

The Vertex-Edge Visibility Graph Of A Polygon, Joseph O'Rourke, Ileana Streinu

Computer Science: Faculty Publications

We introduce a new polygon visibility graph, the vertex-edge visibility graph GV E, and demonstrate that it encodes more geometric information about the polygon than does the vertex visibility graph GV. © 1998 Elsevier Science B.V.

Automatic Granularity Control For Load Balancing Of Concurrent Particle Simulations, Marc Rieffel, Stephen Taylor, Jerrell Watts

Electrical Engineering and Computer Science - All Scholarship

This paper demonstrates the use of automatic granularity control as part of dynamic load balancing for irregular, particle-based simulations. Performance optimization techniques are considered in the context of a concurrent Direct Simulation Monte Carlo method used to study the rarefied gas flow inside three-dimensional plasma reactors. Several computational techniques are used to reduce the overall time to deliver realistic threedimensional results. The effectiveness of dynamic load balancing and granularity control are presented for large-scale simulations on distributed-memory multicomputers.

Specification-Driven Optimization, Sheena Day

Dissertations and Theses

Traditionally, optimizing transformations have been built into compilers. The end-user has little or no control over guiding any optimizations that may be applied by the compiler. Moreover, the compiler-writer does not have a simple way to direct the optimizations. Thus, many potentially beneficial opportunities for code optimization may be lost. We have built a system that allows the user to participate in guiding source-to-source transformations via the specification of rewrite rules. A clean separation of the rules from the strategy of applying them makes the system easier to use and modify, compared to other integrated systems. This is especially relevant …

Object-Oriented Computer Simulations Of Physical Systems Using Dual Reciprocity Boundary Element Methodology, J. Friedrich

Turkish Journal of Electrical Engineering and Computer Sciences

Models of physical systems are essential in every engineering field. This work deals with computer simulations of physical systems that can be mathematically modelled by differential equations together with sufficient boundary conditions. The computer simulations are based on object-oriented technology and the dual reciprocity boundary element method which is a universal solution scheme for various types of partial differential equations (e.g. Laplace, Poisson, diffusion, convection-diffusion, and steady Navier-Stokes equation). This technique fulfills efficiency criteria like precision, robustness, versatility, programmability, user-friendliness, need of computational time and computer memory to a very high degree. This is demonstrated by three examples: Laplace's solution …

Distribution System Planning Usign Mixed Integer Programming, Belgin Türkay

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents an improved mathematical model to optimise the size and locations of substations and the network routing problem. The model was formulated to minimise the total cost of the network by determining the optima of the substation locations and power, the load transfers between the demand centers, the feeder routes and the load flow in the network subject to a set of constraints. The computational results of a devised sample problem indicate that the developed optimisation model and its code are adequate for computer aided planning of distribution systems.

Analysis Of Nonlinear Sustained Oscillations In Discrete Systems With Backlash And Resolution By Using A Discretization-Oriented Describing Function, M. De La Sen, A. Pena, J. Esnaola

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a discretization-oriented describing function is derived for nonlinear devices combining backlash and quantization (resolution) while being subject to discretization through a sampler and zero-order hold. Such a describing function is frequency-dependent so that the overall nonlinearity, which includes both resolution and backlash, is interpreted as possessing nonlinear inertia. That nonlinear inertia is generated by the sampling process, since it does not appear if the system is continuous. The presence of nonlinear sustained oscillations (limit cycles) is investigated through simulations.

Signal Injection With Perceptual Criteria, T. Engi̇n Tuncer

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a novel method for increasing the coding performance and information transmission capacity is presented. This method is mainly based on perceptual modelling of input signal such as speech or audio. Presented approach may be seen as an alternative to transforms which dynamically change analysis window for better energy compaction. A perceptual model is established in order to obtain a global masking threshold in frequency below which sounds become inaudible. Certain criteria are developed for identifying the signal injection bands. A new multiband filter design method which is a generalization of windowing method is used to separate the …

State Of Art In Realistic Head Modeling For Electro-Magnetic Source Imaging Of The Human Brain, Nevzat G. Gençer, İ. Oğuz Tanzer, M. Kemal Özdemi̇r, Can E. Acar, Mert Sungur

Turkish Journal of Electrical Engineering and Computer Sciences

Electric currents produced by the neural activity in the brain create electric potentials on the scalp and magnetic field distribution outside the scalp. Measuring electric and magnetic fields provides a means to understand the spatio-temporal distribution of the neural activity. The representations of the intracellular electric current of active cell populations based on bimodal data are called electro-magnetic source image (EMSI). With the recent development of large arrays of magnetic sensors, and systems for measuring scalp voltages at more than 100 locations, it is now feasible to implement computational methods that employ numerical models which incorporate the correct geometry and …

Percentile Blobs For Image Similarity, Nicholas Howe

Computer Science: Faculty Publications

We present a new algorithm called PBSIM for computing image similarity, based upon a novel method of extracting bloblike features from images. In tests on a classification task using a data set of over 1000 images, PBSIM shows significantly higher accuracy than algorithms based upon color histograms, as well as previously reported results for another approach based upon bloblike features.