Digital Commons Network^™

Inverse Synthetic Aperture Radar Imaging Using A Coherent Ultrawideband Random Noise Radar System, Daryl C. Bell, Ram M. Narayanan

Department of Electrical and Computer Engineering: Faculty Publications

The University of Nebraska-Lincoln has developed an ultrawideband random noise radar operating over the 1- to 2-GHz frequency range. The system uses the technique of heterodyne correlation, and is thus phase coherent. It has therefore been used in applications such as interferometry, polarimetry, and Doppler estimation. This assesses the performance of this radar as a range-Doppler imaging system, in particular, inverse synthetic aperture radar (ISAR). By performing turntable experiments, we examine a number of issues that arise both from the wideband nature of the radar system and from the randomness of the transmit signal. Although the ultrawideband nature of the …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 17, Number 8, May 2001, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

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

Assessing The Predictive Accuracy Of Complex Simulation Models, Timothy Ross, Vladik Kreinovich, Cliff Joslyn

Departmental Technical Reports (CS)

No abstract provided.

Comparison Of Two Distributed Fuzzy Logic Controllers For Flexible-Link Manipulators, Linda Z. Shi, Mohamed Trabia

Mechanical Engineering Faculty Presentations

The paper suggests that fuzzy logic controllers present a computationally efficient and robust alternative to conventional controllers. The paper presents two possible structures for the distributed fuzzy logic controller of a single-link flexible manipulator. A linear quadratic regulator method is used to prove the effectiveness of fuzzy logic controllers.

Overview Of Acousto-Optic Bistability, Chaos, And Logical Applications, Monish Ranjan Chatterjee, Erol Sonmez

Electrical and Computer Engineering Faculty Publications

An overview is presented of the key results in the field of acousto-optic bistability in the past two decades. It is shown that the basic acousto-optic bistable device may be described as a nonlinear dynamical system which satisfies a quadratic map. Thereafter, details are presented of several analytical methods, computer modeling approaches, including the SPICE circuit modeling technique, and experiments that have been used to understand the phenomenon.

Extensions to logical and digital applications are also discussed.

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 17, Number 7, April 2001, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

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

Which Truth Values In Fuzzy Logics Are Definable?, Hung T. Nguyen, Vladik Kreinovich, Antonio Di Nola

Departmental Technical Reports (CS)

In fuzzy logic, every word or phrase describing uncertainty is represented by a real number from the interval [0,1]. There are only denumerable many words and phrases, and continuum many real numbers; thus, not every real number corresponds to some commonsense degree of uncertainty. In this paper, for several fuzzy logic, we describe which numbers are describing such degrees, i.e., in mathematical terms, which real numbers are definable in the corresponding fuzzy logic.

Computational Complexity Of Planning With Temporal Goals, Chitta Baral, Vladik Kreinovich, Raul A. Trejo

Departmental Technical Reports (CS)

In the last decade, there has been several studies on the computational complexity of planning. These studies normally assume that the goal of planning is to make a certain fluent true after the sequence of actions. In many real-life planning problems, the goal is represented in a much more complicated temporal form: e.g., in addition to having a desired fluent true at the end, we may want to keep certain fluents true at all times. In this paper, we study the complexity of planning for such temporal goals. We show that for goals expressible in Linear Temporal Logic, planning has …

Interval Computations As A Particular Case Of A General Scheme Involving Classes Of Probability Distributions, Scott Ferson, Lev Ginzburg, Vladik Kreinovich, Harry Schulte

Departmental Technical Reports (CS)

Traditionally, in science and engineering, measurement uncertainty is characterized by a probability distribution; however, we don't know this probability distribution exactly, so we must consider classes of probability distributions. Interval computations deal with a very specific type of such classes: classes of all distributions which are located on a given interval. We show that in general, we need all convex classes of probability distributions.

1st Order, 2nd Order, What Next? Do We Really Need Third-Order Descriptions: A View From A Realistic (Granular) Viewpoint, Vladik Kreinovich, Hung T. Nguyen

Departmental Technical Reports (CS)

To describe experts' uncertainty in a knowledge-based system, we usually use numbers from the interval [0,1] (subjective probabilities, degrees of certainty, etc.). The most direct way to get these numbers is to ask the expert; however, the expert may not be 100\% certain what exactly number describes his uncertainty; so, we end up with a second-order uncertainty - a degree of certainty describing to what extent a given number d adequately describes the expert's uncertainty about a given statement A. At first glance, it looks like we should not stop at this second order: the expert is probably as uncertain …

Computing The Shape Of The Image Of A Multi-Linear Mapping Is Possible But Computationally Intractable: Theorems, Raul A. Trejo, Vladik Kreinovich

Departmental Technical Reports (CS)

In systems without inertia (or with negligible inertia), a change in the values of control variables x1,...,xn leads to the immediate change in the state z of the system. In more precise terms, for such systems, every component zi of the state vector z=(z1,...,zd) is a function of the control variables. When we know what state z we want to achieve, the natural question is: can we achieve this state, i.e., are there values of the control variables which lead to this very state?

The simplest possible functional dependence is described by linear functions. For such functions, the question of …

An Even More Realistic (Non-Associative) Interval Logic And Its Relation To Psychology Of Human Reasoning, I. R. Goodman, Raul Trejo, Vladik Kreinovich, Jesus Martinez, Reginaldo Gonzalez

Departmental Technical Reports (CS)

No abstract provided.

Why Unary And Binary Operations In Logic: General Result Motivated By Interval-Valued Logics, Hung T. Nguyen, Vladik Kreinovich, I. R. Goodman

Departmental Technical Reports (CS)

Traditionally, in logic, only unary and binary operations are used as basic ones - e.g., "not", "and", "or" - while the only ternary (and higher order) operations are the operations which come from a combination of unary and binary ones. For the classical logic, with the binary set of truth values {0,1}, the possibility to express an arbitrary operation in terms of unary and binary ones is well known: it follows, e.g., from the well known possibility to express an arbitrary operation in DNF form. A similar representation result for [0,1]-based logic was proven in our previous paper. In this …

How To Make Sure That "~100" + 1 Is ~100 In Fuzzy Arithmetic: Solution And Its (Inevitable) Drawbacks, Vladik Kreinovich, Hung T. Nguyen, Witold Pedrycz

Departmental Technical Reports (CS)

From the commonsense viewpoint, if a person who weighs around 100 kilograms gains one more kilogram, his weight is still around 100 kilograms. Alas, not so in traditional fuzzy arithmetic. In this paper, we propose a modification of fuzzy arithmetic which does have this property. We gain the desired property, but there is no free lunch, we have to lose two important properties of the traditional fuzzy arithmetic: first, addition is no longer always associative; second, addition is no longer always easily computable.

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 17, Number 6, March 2001, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

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

Multicast Algorithms For Mobile Satellite Communication Networks, Ryan W. Thomas

Theses and Dissertations

With the rise of mobile computing and an increasing need for ubiquitous high speed data connections, Internet-in-the-sky solutions are becoming increasingly viable. To reduce the network overhead of one-to-many transmissions, the multicast protocol has been devised. The implementation of multicast in these Low Earth Orbit (LEO) constellations is a critical component to achieving an omnipresent network environment. This research examines the system performance associated with two terrestrial-based multicast mobility solutions, Distance Vector Multicast Routing Protocol (DVMRP) with mobile IP and On Demand Multicast Routing Protocol (ODMRP). These protocols are implemented and simulated in a six plane, 66 satellite LEO constellation. …

Infosphere Project: An Overview, Calton Pu, Jonathan Walpole

Computer Science Faculty Publications and Presentations

We describe the Infosphere project, which is building the systems software support for information-driven applications such as digital libraries and electronic commerce. The main technical contribution is the Infopipe abstraction to support information flow with quality of service. Using building blocks such as program specialization, software feedback, domain-specific languages, and personalized information filtering, the Infopipe software generates code and manage resources to provide the specified quality of service with support for composition and restructuring.

Modeling The Transient Rate Behavior Of Bandwidth Sharing As A Hybrid Control System, Kang Li, Molly H. Shor, Jonathan Walpole, Calton Pu

Computer Science Faculty Publications and Presentations

This paper uses hybrid control to model a problem of computer network systems, the dynamic behavior of bandwidth sharing among competing TCP traffic. It has been well known in the computer network community that well-behaved (TCP-friendly) congestion control mechanisms are crucial to the robustness of the Internet. Congestion control determines the transmission rate for each flow. Right now, most TCP-friendly research focuses only on the average throughput behavior without considering how the data is sent out in the short-term (e.g. bursty or smooth). However, recent experimental results show that short-term rate adjustments can change the bandwidth sharing result. Therefore, it …

Moving Towards Massively Scalable Video-Based Sensor Networks, Wu-Chi Feng, Jonathan Walpole, Calton Pu, Wu-Chang Feng

Computer Science Faculty Publications and Presentations

Networking and computing technologies are becoming advanced enough to enable a wealth of diverse applications that will drastically change our everyday lives. Some past examples of these developments include the World Wide Web and wireless data networking infrastructures. As is quite obvious, the World Wide Web has enabled a fundamental change in the way many people deal with day-to-day tasks. Through the web, one can now make on-line reservations for travel, pay bills through on-line banking services, and view personalized on-line newscasts. More recently, developments in wireless technologies have enabled anywhere, anytime access to information over wireless medium. As wireless …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 17, Number 5, February 2001, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

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

The Prospect For Answer Sets Computation By A Genetic Model, A. Bertoni, G. Grossi, A. Provetti, Vladik Kreinovich, L. Tari

Departmental Technical Reports (CS)

We combine recent results from both Logic Programming and Genetic Algorithms to design a new method for the efficent computation of Answer Sets of logic programs. First of all the problem is reduced to the problem of finding a suitable coloring on directed graphs. Then the problem of finding a suitable coloring is relaxed to a combinatorial optimization problem and solved (in an approximate way) by a continuous discrete time system derived by a genetic model.

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 17, Number 4, January 2001, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

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

Design And Develop A Generic Cut-Through Switch, Nazaruddin Noraini

Student Works (2000-2009)

Today's advancement in network is related to the advancement of packet switching technology. Switching directs network traffic in an efficient manner – it sends information directly from the port of origin to only its destination port. Without switching, many networks are experiencing bandwidth shortages because of an increase in traffic due to the increased numbers of users, the amount of data transported between client/server applications, and the inefficient traffic patterns of some networks. Transmission of data from one destination to another is unguaranty successful. Sometimes the data will lost or conupted during transmission to destination port. To make data more …

Local Search And Encoding Schemes For Soft Constraint Minimization Problems, Michael P. Moran, Weixiong Zhang

All Computer Science and Engineering Research

Soft constraint minimization problems (SCMPs) contain hard constraints that cannot be violated and soft constraints that may be violated but carry penalties if not satisfied. In this paper, we first extend local search, WalkSAT in particular, to SCMPs and study the existing SAT encoding schemes for SCMPs. We propose a general encoding method called k-encoding. We then investigate the effects of local search neiborhood structures introduced by encoding schemes and analyze the anytime performance of extended WalkSAT using different encoding methods. Our experimental results on various graph coloring problems show that a direct extension of WalkSAT is most effective, and …

Formal Specification And Design Of Mobile Systems, Gruia-Catalin Roman, Christine Julien, Qingfeng Huang

All Computer Science and Engineering Research

Termination detection, a classical problem in distributed computing, is revisited in the new setting provided by the emerging mobile computing technology. A simple solution tailored for use in ad hoc networks is employed as a vehicle for demonstrating the applicability of formal requirements and design strategies to the new field of mobile computing. The approach is based on well understood techniquest in specification refinement, but the methodology is tailored to mobile applications and helps designers address novel concerns such as the mobility of hosts, transient interactions, and specific coordination constructs. The proof logic and programming notation of Mobile UNITY provide …

Aggregated Hierarchical Multicast For Active Networks, Tilman Wolf, Sumi Y. Choi

All Computer Science and Engineering Research

Active Networking is the basis for a range of new and innovative applications that make use of computational resources inside network routers. One such application is Aggregated Hierarchical Multicast, which aims at implementing efficient many-to-many communication. In certain scenarios it is possible to transmit less accurate, aggregated data and thus achieve better scalability. Using Active Networks, this aggregation computation can be done transparently by network routers without end system support. We present how aggregated data streams can be structured in a hierarchical fashion to allow easy access of data at the desired aggregation level. We introduce two application examples to …

A Proposal For A Scalable Internet Multicast Architecture, Sherlia Shi

All Computer Science and Engineering Research

We propose a new network and system architecture for multicast in the Internet. Our main objectives are to find a cost-effective way to scale to a large number of multicast groups whose members are geographically dispersed, and to enable small and less capable devices to participate in group communications. In order to preserve the efficiency of data distribution gained by multicast, while avoiding the control complexity previously exhibited by IP multicast, we propose the use of an overlay network for multicast services. We construct "virtual" multicast trees, which consist of unicast connections joining multicast servers in the network. These servers …

Fast Incremental Crc Updates For Ip Over Atm Networks, Florian Braun, Marcel Waldvogel

All Computer Science and Engineering Research

In response to the increasing network speeds, many operations in IP routers and similar devices are being made more efficient. With the advances in other areas of packet processing, the verification and regeneration of cyclic redundancy check (CRC) codes of the data link layer is likely to become a bottleneck in the near future. In this paper, we present a mechanism to defer CRC verification without compromising reliability. This opens the possibility of incremental updates of the CRC. We introduce a new high-speed technique and present efficient implementation, speeding up CRC processing by a factor of 15. Although the paper …

Layered Protocol Wrappers For Internet Packet Processing In Reconfigurable Hardware, Florian Braun, John Lockwood, Marcel Waldvogel

All Computer Science and Engineering Research

The ongoing increases of line speed in the Internet backbone combined with the need for increased functionality of network devices presents a major challenge. These demands call for the use of reprogrammable hardware to provide the required flexible, high-speed functionality, at all network layers. The Field Programmable Port Extender (FPX) provides such an environment for development of networking components in reprogrammable hardware. We present a framework to streamline and simplify networking applications that process ATM cells, AAL5 frames, Internet Protocol (IP) packets and UDP datagrams directly in hardware.

Phase Transitions And Backbones Of Constraint Minimization Problems, Weixiong Zhang

All Computer Science and Engineering Research

Many real-world problems involve constraints that cannot be all satisfied. The goal toward an overconstrained problem is to find solutions minimizing the total number of constraints violated. We call such a problem constraint minimization problem (CMP). We study the behavior of the phase transitions and backbones of CMP. We first investigate the relationship between the phase transitions of Boolean satisfiability, or precisely 3-SAT (a well-studied NP-complete decision problem), and the phase transitions of MAX 3-SAT (an NP-hard optimization problem). To bridge the gap between the easy-hard-easy phase transitions of 3-SAT, in which solutions of bounded quality, e.g., solutions with at …