Engineering Commons^™

Knowledge-Based Navigation For Autonomous Road Vehicles, Murat Eki̇nci̇, Franches W.J.Gibbs, Barry T. Thomas

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a computer vision system for an autonomous road vehicle (ARV) that is capable of negotiating complex road networks including road junctions in real time. The ultimate aim of the system is to enable the vehicle to drive automatically along a given complex road network whose geometric description is known. This computer vision system includes three main techniques which are necessary for an ARV: a) road following, b) road junction detection, c) manoeuvring at the road junction. The road following algorithm presents a method of executing a number of algorithms using different methods concurrently, fusing their outputs together …

Decentralised H_{\Infty} Load Frequency Controller Design Based On Ssvs, Hasan Çi̇men

Turkish Journal of Electrical Engineering and Computer Sciences

The decentralised load-frequency controller design problem concerned is translated into an equivalent problem of decentralised controller design for a multi-area multi-input multi-output (MIMO) control system. It is shown that subject to a condition based on the structured singular values (SSVs), each local area load-frequency controller can be designed independently. The stability condition for the overall system can be stated as to achieve a sufficient interaction margin. It is demonstrated by computer simulation that within this general framework, local H$_{\infty}$ controllers can be designed to achieve satisfactory performances for a sample two-area power system.

Information And Average Information Rates Of A Graphical Access Structure On Six Vertices, Mustafa Atici

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper we study the optimal information and average information rates of secret sharing schemes which are all connected graphs on six vertices. There are $102$ connected graphs on six vertices that are not complete multipartite graphs. Of these $102$ graphs, we determined the optimal information rate of $71$ graphs, and the optimal average information rate of $88$ graphs.

Comparison Of Simulation Algorithms For The Hopfield Neural Network: An Application Of Economic Dispatch, Tankut Yalçinöz, Hali̇s Altun

Turkish Journal of Electrical Engineering and Computer Sciences

This paper is mainly concerned with an investigation of the suitability of Hopfield neural network structures in solving the power economic dispatch problem. For Hopfield neural network applications to this problem three important questions have been answered: what the size of the power system is; how efficient the computational method; and how to handle constraints. A new mapping process is formulated and a computational method for obtaining the weights and biases is described. A few simulation algorithms used to solve the dynamic equation of the Hopfield neural network are discussed. The results are compared with those of a classical technique, …

Radiation From An Impedance Loaded Parallel-Plate Waveguide, Fi̇li̇z Bi̇rbi̇r, Ali̇nur Büyükaksoy

Turkish Journal of Electrical Engineering and Computer Sciences

A hybrid method consisting of employing the mode matching method in conjunction with the Fourier transform technique is used to analyze the radiation of the dominant TEM-wave from an impedance loaded parallel-plate waveguide. The hybrid method that we adopt here reduces the related boundary value problem to a scalar modified Wiener-Hopf equation of the second kind. The solution involves infinitely many unknown constants satisfying an infinite system of linear algebraic equations susceptible to a numerical treatment. Some computational results illustrating the effects of various parameters on the radiation phenomenon are also presented.

A Pseudo Spot Price Algorithm Applied To The Pumped-Storage Hydraulic Unit Scheduling Problem, Sali̇h Fadil, Celal Yaşar

Turkish Journal of Electrical Engineering and Computer Sciences

A lossy electric power system that contains thermal units and a pumped-storage hydraulic unit is considered in this paper. The total cost of thermal units in an operation cycle is minimized under some possible electric and hydraulic constraints of the units. The operation cycle is divided into time intervals where the system loads are assumed to remain constant. The proposed solution technique has two main parts. In the first part, the active thermal generations and active generation or pumping power of the pumped-storage unit in all time intervals are determined by using units' active generation incremental costs and pseudo spot …

Distance Spectra For Trellis Coded Modulation Schemes On Channels With Intersymbol Interference, Sabi̇re Haciömeroğlu, Melek D. Yücel

Turkish Journal of Electrical Engineering and Computer Sciences

The effect of intersymbol interference on distance spectra for trellis coded 8-PSK, 16-QAM and 32-AMPM modulation schemes is evaluated using the methods proposed by Schlegel. Distance spectra of 16-state 8-PSK scheme are computed for different intersymbol interference channels. It is seen that on channels with intersymbol interference the spectral lines are spread into a nearly continuous spectrum and the minimum Euclidean distance between codewords decreases severely. Hence, although the main contribution at large signal to noise ratios comes from the minimum Euclidean distance ( d_{free} ) , higher spectral components also become very important at moderate values of the signal …

A Fuzzy Identification Method For Nonlinear Systems, İbrahi̇m Eksi̇n, Osman Kaan Erol

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, two mathematical ways of building a fuzzy model of both linear and nonlinear systems are presented and compared. In order to determine a model for a nonlinear system, the phase plane is divided into sub-regions and a linear model is assigned for each of these regions. This linear model is represented either in state-space or ARX model form. To determine the pre-selected parameters of the linear system model under study, least-square identification method is used. Then these linear models are arranged in a fuzzy manner to characterize the overall system behavior. The results show that this method …

Control Chart Pattern Recognition Using Artificial Neural Networks, Şeref Sağiroğlu, Erkan Beşdok, Mehmet Erler

Turkish Journal of Electrical Engineering and Computer Sciences

Precise and fast control chart pattern (CCP) recognition is important for monitoring process environments to achieve appropriate control and to produce high quality products. CCPs can exhibit six types of pattern: normal, cyclic, increasing trend, decreasing trend, upward shift and downward shift. Except for normal patterns, all other patterns indicate that the process being monitored is not functioning correctly and requires adjustment. This paper describes a new type of neural network for speeding up the training process and to compare three training algorithms in terms of speed, performance and parameter complexity for CCP recognition. The networks are multilayered perceptrons trained …

Extracting Fuzzy Sparse Rule Base By Cartesian Representation And Clustering, Yeung Yam, Vladik Kreinovich, Hung T. Nguyen

Departmental Technical Reports (CS)

Sparse rule base and interpolation have been proposed as possible solution to alleviate the geometric complexity problem of large fuzzy set. However, no formal method to extract sparse rule base is yet available. This paper combines the recently introduced Cartesian representation of membership functions and a mountain method-based clustering technique for extraction. A case study is included to demonstrate the effectiveness of the approach.

Intervals (Pairs Of Fuzzy Values), Triples, Etc.: Can We Thus Get An Arbitrary Ordering?, Vladik Kreinovich, Masao Mukaidono

Departmental Technical Reports (CS)

Traditional fuzzy logic uses real numbers as truth values. This description is not always adequate, so in interval-valued fuzzy logic, we use pairs (t-,t+) of real numbers, t-<=t+, to describe a truth value. To make this description even more adequate, instead of using real numbers to described each value t- and t+, we can use intervals, and thus get fuzzy values which can be described by 4 real numbers each. We can iterate this procedure again and again. The question is: can we get an arbitrary partially ordered set in this manner? An arbitrary lattice? In this paper, we show that although we cannot thus generate arbitrary lattices, we can actually generate an arbitrary partially ordered set in this manner. In this sense, the "intervalization" operation is indeed universal.

Aerospace Applications Of Soft Computing And Interval Computations (With An Emphasis On Multi-Spectral Satellite Imaging), Scott A. Starks, Vladik Kreinovich

Departmental Technical Reports (CS)

This paper presents a brief overview of our research in applications of soft computing and interval computations to aerospace problems, with a special emphasis on multi-spectralsatellite imaging.

Work In Progress: Automating Proportion/Period Scheduling, David Steere, Jonathan Walpole, Calton Pu

Computer Science Faculty Publications and Presentations

The recent effort to define middleware capable of supporting real-time applications creates the opportunity to raise the level of abstraction presented to the programmer. We propose that proportion/period is a better abstraction for specifying resource needs and allocation than priorities. We are currently investigating techniques to address some issues that are restricting use of proportion/period scheduling to research real-time prototypes. In particular, we are investigating techniques to automate the task of selecting proportion and period, and that allow proportion/period to incorporate job importance under overload conditions.

Network Security Versus Network Connectivity: A Framework For Addressing The Issues Facing The Air Force Medical Community, Franklin E. Cunningham Jr.

Theses and Dissertations

The Air Force has instituted Barrier Reef to protect its networks. The Air Force medical community operates network connections that are incompatible with Barrier Reef. To overcome this problem, OASD(HA) directed the Tri-Service Management Program Office (TIMPO) to develop an architecture that protects all military health systems and allows them to link with all three services and outside partners. This research studied the underlying networking issues and formed a framework based on data from network experts from the Air Force's medical centers and their base network organizations. The findings were compared TIMPO and a composite framework was developed that more …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 9, November 1999, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

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

For Interval Computations, If Absolute-Accuracy Optimization Is Np-Hard, Then So Is Relative-Accuracy Optimization, Vladik Kreinovich

Departmental Technical Reports (CS)

One of the basic problems of interval computations is to compute a range of a given function f(x1,...,xn) over a given box (i.e., to compute the maximum and the minimum of the function on the box). For many classes of functions (e.g., for quadratic functions) this problem is NP-hard; it is even NP-hard if instead of computing the minimum and maximum exactly, we want to compute them with a given (absolute) accuracy. In practical situations, it is more realistic to ask for a relative accuracy; are the corresponding problems still NP-hard? We show that under some reasonable conditions, NP-hardness of …

Geombinatoric Aspects Of Processing Large Images And Large Spatial Databases, Jan Beck, Vladik Kreinovich, Brian Penn

Departmental Technical Reports (CS)

Computer processing can drastically improve the quality of an image and the reliability and accuracy of a spatial database. A large image (database) does not easily fit into the computer memory, so we process it by downloading pieces of the image. Each downloading takes a lot of time, so, to speed up the entire processing, we must use as few pieces as possible.

Many algorithms for processing images and spatial databases consist of comparing the value at a certain spatial location with values at nearby locations. For such algorithms, we must select (possibly overlapping) sub-images in such a way that …

An Optimal Fft-Based Algorithm For Mosaicking Images, With Applications To Satellite Imaging And Web Search, Stephen Gibson, Olga Kosheleva, Luc Longpre, Brian Penn, Scott A. Starks

Departmental Technical Reports (CS)

Digital data storage is becoming ever more abundant and cheap. This, along with other technological advances, has brought about an age of mass storage of information, much of it in the form of images. In order to be able to process these stockpiles of image data, new and faster computer algorithms are needed.

One area of interest is that of image mosaicking, i.e., comparing two overlapping images and finding the proper scaling, angle of rotation, and translation needed to fit one with the other. Early methods for mosaicking images included visual inspection or exhaustive, pixel by pixel, search for the …

Towards Mathematical Foundations Of Information Retrieval: Dependence Of Website's Relevance On The Number Of Occurrences Of A Queried Word, Laszlo Koczy, Vladik Kreinovich, Yohanz Mendoza, Hung T. Nguyen, Harry Schulte

Departmental Technical Reports (CS)

In response to a query, web search tools often return many websites which are not really relevant. One reason for this is that the queried word may have several meanings different to the one which the user has in mind. To eliminate these undesirable meanings, it is reasonable to look for occurrences not only of the queried word itself, but also for other words related to this particular meaning, and then select only the websites for which, based on this information, we are confident about their relevance. For this strategy to work, we must be able to estimate the degree …

Investigation Of Image Feature Extraction By A Genetic Algorithm, Steven P. Brumby, James P. Theiler, Simon J. Perkins, Neal R. Harvey, John J. Szymanski, Jeffrey J. Bloch, Melanie Mitchell

Computer Science Faculty Publications and Presentations

We describe the implementation and performance of a genetic algorithm which generates image feature extraction algorithms for remote sensing applications. We describe our basis set of primitive image operators and present our chromosomal representation of a complete algorithm. Our initial application has been geospatial feature extraction using publicly available multi-spectral aerial-photography data sets. We present the preliminary results of our analysis of the efficiency of the classic genetic operations of crossover and mutation for our application, and discuss our choice of evolutionary control parameters. We exhibit some of our evolved algorithms, and discuss possible avenues for future progress.

Candidate Sets For Complex Interval Arithmetic, Juergen Wolff Von Gundenberg, Vladik Kreinovich

Departmental Technical Reports (CS)

Uncertainty of measuring complex-valued physical quantities can be described by complex sets. These sets can have complicated shapes, so we would like to find a good approximating family of sets. Which approximating family is the best? We reduce the corresponding optimization problem to a geometric one: namely, we prove that, under some reasonable conditions, an optimal family must be shift-, rotation- and scale-invariant. We then use this geometric reduction to conclude that the best approximating low-dimensional families consist of sets with linear or circular boundaries. This result is consistent with the fact that such sets have indeed been successful in …

A Geometric Approach To Classification Of Trash In Ginned Cotton, Murali Siddaiah, Michael A. Lieberman, Nadipuram R. Prasad, Vladik Kreinovich

Departmental Technical Reports (CS)

This paper discusses the use of geometric approach to classify different types of trash (non-lint, non-fiber material) in ginned cotton. Pieces of trash can have complicated shapes, so we would like to find a good approximating family of sets. Which approximating family is the best? We reduce the corresponding optimization problem to a geometric one: namely, we show that, under some reasonable conditions, an optimal family must be shift-, rotation- and scale-invariant. We then use this geometric reduction to conclude that the best approximating low-dimensional families consist of sets with linear or circular boundaries.

This result is in good agreement …

Interval Methods In Non-Destructive Testing Of Material Structures, Keith Worden, Roberto A. Osegueda, Carlos M. Ferregut, Soheil Nazarian, Debra L. George, Mary J. George, Vladik Kreinovich, Olga Kosheleva, Sergio Cabrera

Departmental Technical Reports (CS)

In many practical situations, e.g., in aerospace applications and in mammography, it is important to test the structural integrity of material structures. We show that interval methods can help.

From Fuzzy Values To Intuitionistic Fuzzy Values To Intuitionistic Fuzzy Intervals Etc.: Can We Get An Arbitrary Ordering?, Vladik Kreinovich, Masao Mukaidono, Krassimir Atanassov

Departmental Technical Reports (CS)

Traditional fuzzy logic uses real numbers as truth values. This description is not always adequate, so in intuitionistic fuzzy logic, we use pairs of real numbers to describe a truth value. Such pairs can be described either as pairs (t,f) for which t+f<=1, or, alternatively, as pairs (t,1-f) for which t<=1-f. To make this description even more adequate, instead of using real numbers to described each value t and f, we can use intervals, and thus get interval-valued intuitionistic fuzzy values which can be described by 4 real numbers each. We can iterate this procedure again and again. The question is: can we get an arbitrary partially ordered set in this manner? An arbitrary lattice? In this paper, we show that although we cannot thus generate arbitrary lattices, we can actually generate an arbitrary partially ordered set in this manner. In this sense, the "intervalization" operation which underlies the notion of an intuitionistic fuzzy set, is indeed universal.

From Interval Methods Of Representing Uncertainty To A General Description Of Uncertainty, Vladik Kreinovich, Scott Ferson, Lev Ginzburg, Harry Schulte, Matthew R. Barry, Hung T. Nguyen

Departmental Technical Reports (CS)

Measurements do not result in an exact value of the measured quantity; even after the most accurate measurement, there is still some uncertainty about the actual value of the measured quantity. Traditionally, in science and engineering, this uncertainty is characterized by a probability distribution; however, often, we do not know this probability distribution exactly. So, to get a more adequate description of this uncertainty, we must consider classes of possible probability distributions. A natural question is: Are all possible classes needed for this description? In this paper, we show that even for simple situations, we indeed need arbitrary closed convex …

On Combining Statistical And Fuzzy Techniques: Detection Of Business Cycles From Uncertain Data, Hung T. Nguyen, Berlin Wu, Vladik Kreinovich

Departmental Technical Reports (CS)

Detecting the beginning and the end of the business cycle is an important and difficult economic problem. One of the reasons why this problem is difficult is that for each year, we have only expert estimates (subjective probabilities) indicating to what extent the economy was in growth or recession. In our previous papers, we used fuzzy techniques to process this uncertain information; namely, we used the operation min(a,b) to combine the subjective probabilities (expert estimates) of two events into a probability that both events happen. This function corresponds to the most optimistic estimate of the joint probability. In this paper, …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 8, October 1999, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

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

The Internet Name Game And The Nonprofit Solution, Roger A. Lohmann

Faculty & Staff Scholarship

This paper is a case study of the campaign to create a new internet names authority to handle the assignment of internet domain names. Almost everyone knows by now that the Internet was originally a defense research project, which morphed into a research network for scientists and then into a tool of higher education and eventually into the commercial and general household utility we know today. In terms familiar to nonprofit research community what began in the state sector, expanded into the third sector and then into the market and household sectors and the consumer economy. There is a second …

Theory Of Photon Coincidence Statistics In Photon-Correlated Beams, Majeed M. Hayat, Sergio N. Torres, Leno M. Pedrotti

Electrical and Computer Engineering Faculty Research and Publications

The statistics of photon coincidence counting in photon-correlated beams is thoroughly investigated considering the effect of the finite coincidence resolving time. The correlated beams are assumed to be generated using parametric downconversion, and the photon streams in the correlated beams are modeled by two partially correlated Poisson point processes. An exact expression for the mean rate of coincidence registration is developed using techniques from renewal theory. It is shown that the use of the traditional approximate rate, in certain situations, leads to the overestimation of the actual rate. The error between the exact and approximate coincidence rates increases as the …

System And Method For Improving Data Acquisistion Capability In Spectroscopic Rotatable Element, Rotating Element, Modulation Element, And Other Ellipsometer And Polarimeter And The Like Systems, Steven E. Green, Craig M. Heringer, Blaine D. Johs, John A. Woollam, Stephen P. Ducharme

Department of Electrical and Computer Engineering: Faculty Publications

Disclosed is a System and method for controlling polarization State determining parameters of a polarized beam of light in an ellipSometer or polarimeter and the like System, (e.g. a modulation element ellipsometer System), So that they are in ranges wherein the Sensitivity, (of a Sample system characterizing PSI and DELTA value monitoring detector used to measure changes in Said polarization State resulting from interaction with a “composite Sample System,” comprised of a Sample System per Se.. and a beam polarization State determining variable retarder, to noise and measurement errors etc. therein), is reduced. The present invention allows determining Sample System …