Digital Commons Network^™

On The Optimal Choice Of Quality Metric In Image Compression, Olga Kosheleva, Vladik Kreinovich, Yeung Yam

Departmental Technical Reports (CS)

No abstract provided.

Open-Ended Configurations Of Radio Telescopes: Geometrical Analysis, Vladik Kreinovich, Scott A. Starks, Dima Iourinski, Olga Kosheleva, Andrei Finkelstein

Departmental Technical Reports (CS)

No abstract provided.

Was There Satan's Face In The World Trade Center Fire? A Geometric Analysis, Vladik Kreinovich, Dima Iourinski

Departmental Technical Reports (CS)

Some photos of the 2001 World Trade Center fire reveal a "face" in the smoke which was interpreted, by some people, as the face of Satan. Most journalists believe, however, that the visible smoke configuration can be explained by natural processes, and that the visible "face" is similar to animal shapes that are sometimes observed in the clouds. In this paper, we present a simple geometric analysis that supports this natural-process explanation.

Computational Complexity Of Planning With Discrete Time And Continuous State Variables, Chitta Baral, Vladik Kreinovich

Departmental Technical Reports (CS)

Traditionally, most planning research in AI was concentrated on systems whose state can be characterized by discrete-valued fluents. In many practical applications, however, we want to control systems (like robots) whose state can only be described if we used continuous variables (like coordinates). Planning for such systems corresponds, crudely speaking, to Level 2 of the planing language PDDL2.1. In this paper, we analyze the computational complexity of such planning problems.

Web-Based Interactive Self-Evaluation System For Computer Science In Generic Tutorial System For The Sciences Project, Supachai Praritsantik

Theses Digitization Project

The goal of this master project is to promote and facilitate the use of new web-based and Java-based technologies in the development of self-evaluation systems for computer science; in particular, analysis of sorting algorithms.

Java Prototype Of Hypercard Bibliography Past Implementation And Present Choices, Neeta Reddy

Theses Digitization Project

This project was started with JDK Version 1.0 and was later upgraded to version JDK Version 1.2.2, to create a graphical user interface using the Abstract Window Toolkit (AWT) to a HyperCard bibliography of software engineering. The bibliographic index tool is designed to facilitate searching for text and is run as a Java applet. It presents an alphabetically ordered list of author names and subjects. With the bibliography index tool one can manipulate a bibliographic list directly over the World Wide Web on a computer that lists electronic bibliographies.

An On-Line Acid-Base Titration Applet In The Generic Tutorial System For The Sciences Project, Thomas Lee Gummo

Theses Digitization Project

The purpose of this Master's Project was to develop an Acid-Base Titration Simulator. It was also to be a part of the California State University - San Bernardino's GTSS, Generic Tutorial System for the Sciences, project. The main benefit is that students will be able to conduct titration experiments over the Internet without being in the laboratory and without costly equipment or dangerous chemicals. Instructors at the high school and college level can demonstrate the key principles of titration.

Designing Human-Centered Distributed Information Systems, Jiagie Zhang, Vimla L. Patel, Kathy A. Johnson, Jane Malin, Jack W. Smith

Faculty, Staff and Student Publications

Many computer systems are designed according to engineering and technology principles and are typically difficult to learn and use. The fields of human-computer interaction, interface design, and human factors have made significant contributions to ease of use and are primarily concerned with the interfaces between systems and users, not with the structures that are often more fundamental for designing truly human-centered systems. The emerging paradigm of human-centered computing (HCC)-which has taken many forms-offers a new look at system design. HCC requires more than merely designing an artificial agent to supplement a human agent. The dynamic interactions in a distributed system …

Querying Geographically Dispersed, Heterogeneous Data Stores: The Pperfxchange Approach, Matthew Edward Colgrove

Dissertations and Theses

This thesis details PPerfXchange’s approach for querying geographically dispersed heterogeneous data stores. While elements of PPerfXchange’s method have been implemented for other application areas, PPerfXchange shows how these elements can be applied to parallel performance analysis. The accomplishments of this thesis are:

• The design of an architecture for PPerfXchange, giving a uniform method to query heterogeneous data stores;
• A proof of concept prototype implementation of PPerfXchange including a partial implementation of an XQuery processor and a relational database virtual XML document; and
• Evaluation of PPerfXchange using example parallel performance analysis data.

An Analysis Of A Private-Key Cryptosystem, Wei-Wey Tan

Student Works (2000-2009)

In this dissertation, we have presented a new block cipher. The proposed block cipher is a Substitution-Permutation network cryptosystem with a block length of 128 bits and key length of 256 bits. With the increased key length and block size, the proposed block cipher has greater security over DES. A modular design approach was applied. The cipher has three major building blocks and their interaction has been carefully chosen to achieve better security and performance. Algorithmic S­-Boxes are used to provide confusion and nonlinearity in the cipher. The proposed cipher uses a highly diffusive diffusion layer, which is a combination …

A Genetic Algorithm Solution To The Shortest Path Problem In Ospf And Mpls, Wee Jing Tee Wee Jing

Student Works (2000-2009)

This project studies and explores the potential of using genetic algorithm to solve the shortest path problem in Open Shortest Path First (OSPF) and Multiprotocol Label Switching (MPLS). The most critical task for developing a genetic algorithm to the shortest path problem is to how to encode a path in a network. In this project, two genetic algorithm solutions arc developed for the above two problem domains, i.e. Previous-node-based Encoding to solve the shortest path problem in OSPF and Priority-based Encoding to solve the shortest path problem in MPLS. For each of the shortest path problem domains, the proposed solution …

Issues In Implementing Ipv6 In The X-Kernel Simulator, Raja Singam Thillainathan

Student Works (2000-2009)

The new Internet Protocol Version 6(IPv6) or Internet Protocol Next Generation (TPNG) is bound to replace the existing Internet Protocol Version 4(TPv4). This new protocol is to address and resolve the limitations of the existing Internet Protocols. At the moment the new protocol is still in its infancy stage, and it is being implemented by both the research society and the private sector. The x-kernel being a research project done by University of Arizona is freely available on the Internet. This x-kemel is a networking software almost similar to the Berkeley version (BSD) and it is bundled together with a …

Internet Information Server Scanner : Scanning On Url Vulnerabilities, Yu Jin Tan

Student Works (2000-2009)

This dissertation analyzes weaknesses on web servers, focusing on Microsoft's Internet Information Server (HS). As part of the research, an HS scanner (HS-SCAN) has been implemented to probe only on URL vulnerabilities. The need for a vulnerability scanner stems from the alarming number of successful attacks on computer systems that are connected to the Internet. The security flaws threatening e-businesses and the Internet community has prompted bona fide defense measures. Internet firewalls - gateways controlling access between one network and all the others - became a must-have for any organization connecting to the Net. If the firewall is considered the …

A Vhdl Implementation Of Bist Technique In Uart Design, Mohd. Yamani Idna Idris

Student Works (2000-2009)

No abstract provided.

A 0.5 Μm Thick Polysilicon Schottky Diode With Rectification Ratio Of 10^6, Elena A. Guliants, Chunhai Ji, Young J. Song, Wayne A. Anderson

Electrical and Computer Engineering Faculty Publications

Polycrystalline Si films, 0.5-mm thick, were obtained as a result of metal-induced growth by sputtering from a Si target on 25 nm thick Ni prelayers at 525 °C. Silicon grew heteroepitaxially on the NiSi2 layer formed due to the reaction between the sputtered Si atoms and Ni. Schottky diodes were fabricated on the Si films by deposition of a Schottky metal on the front surface of the film while Ni disilicide provided an intimate ohmic contact at the back. A Pd/n-Si diode using an n-Si film annealed for 2 h at 700 °C in forming gas demonstrated a rectification ratio …

Sar Simulations In Wireless Communication And Safety Discussions In The Society, M. O. Özyalçin, Funda Akleman, Levent Sevgi̇

Turkish Journal of Electrical Engineering and Computer Sciences

Numerical simulation in cellular phone - human tissue interaction is discussed in this paper. The powerful time domain (TD) techniques, the transmission line matrix (TLM) and the finite-difference time-domain (FDTD) methods, are used to model mutual effects. The purpose is to calculate specific absorption rate (SAR; defined as the power absorbed by the unit mass of the tissue), validate the codes and verify the results. Also, effectiveness of the SAR parameter in determination of the exposure limits for human health and environmental pollution is discussed.

Cpl: A Language For Real-Time Distributed Object Programming, Erhan Saridoğan, Nadi̇a Erdoğan

Turkish Journal of Electrical Engineering and Computer Sciences

As processing and time requirements of computer systems increase over the borders of single processor architectures, it is becoming more and more attractive to use distributed computing with additional real-time capabilities. In several cases, traditional programming languages have become insufficient to build distributed systems easily, especially when real-time issues and basic software quality factors are concerned. In this paper, a concurrent, object-oriented, distributed real-time programming language, CPL, with a supportive run-time system, namely the CORD-RTS, is introduced and new language features are described. The new language provides an efficient solution for command and control systems by embedding distribution and real-time …

An Efficient Middleware Architecture Supporting Real-Time Distributed Object Programming, Erhan Saridoğan, Nadi̇a Erdoğan

Turkish Journal of Electrical Engineering and Computer Sciences

With the increasing demand for distributed real-time systems, the need for programming tools and execution platforms useful in development of such application systems is widely recognized. This paper presents CORD-RTS, an efficient middleware architecture that provides support for real-time distributed object programming. The communication infrastructure and various components of the middleware, which support several modes of interactions among distributed real-time objects, along with its real-time features and services, are discussed in detail.

A New Congestion Control Mechanism Proposed For The Sscop Protocol, A. Hali̇m Zai̇m

Turkish Journal of Electrical Engineering and Computer Sciences

International Telecommunication Union, Telecommunications Sector (ITU-T) Recommendation Q.2110 states that the update of a granted credit window to the transmitter (VR(MR)) is implementation dependent. In this paper, a new algorithm is designed to control the traffic flow coming from malfunctioning users. The VR(MR) parameter is controlled for that purpose. The simulation results show that this new technique nearly doubles the system performance.

Walkthrough In Complex Environments At Interactive Rates Using Level-Of-Detail, Alper Selçuk, Uğur Güdükbay, Bülent Özgüç

Turkish Journal of Electrical Engineering and Computer Sciences

One of the biggest problems in computer graphics is displaying huge geometric models at interactive rates. A lot of work has been done to achieve the required frame-rates in architecture, simulation, computer-aided design and entertainment applications. In this paper, a system that enables walkthrough in complex environments using level-of-detail approximations is explained. The system uses hierarchical triangulated models as input. In the preprocessing phase, multiresolution models of objects are created using polygonal simplification techniques. During walkthrough, fast frustum culling based on bounding boxes is performed to eliminate branches of hierarchy that are not visible. An appropriate level for detail of …

A New Petri-Net-Based Synthesis Technique For Supervisory Control Of Discrete Event Systems, Murat Uzam, Anthony H. Jones

Turkish Journal of Electrical Engineering and Computer Sciences

A new Petri-net-based top-down synthesis technique for supervisory control of Discrete Event Systems (DES) is proposed to solve the forbidden state problem. The supervisors obtained are compiled supervisors, whose control policy is represented as a net structure, as opposed to mapping supervisors, whose control policy is computed as a feedback function of the marking of the system. The compiled supervisors obtained by using the technique proposed in this paper are both nonblocking and maximally permissive. The supervisors to be synthesised consist of a controlled Automation Petri Net model of the system. Automation Petri Nets (APN) include the following extensions to …

Approximations On The Aggregate Mpeg Video Traffic And Their Impact On Admission Control, Fati̇h Alagöz

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, we investigate the aggregate traffic approximations for the Motion Pictures Expert Group (MPEG) coded variable bit rate (VBR) video traffic and their impact on admission control at a desired Quality of Service (QoS) level. In order to generate the MPEG coded VBR video traffic, we use a novel source model that employs a mixture of two first-order autoregressive processes with lognormally distributed residuals (2LAR). The model parameters are found based on least square estimates to capture the marginal distribution and autocorrelation function as well as the single server queuing behavior of an MPEG coded empirical bitstream. We …

New Oscillator Topologies Using Inverting Second-Generation Current Conveyors, Ali̇ Toker, Hakan Kuntman, Oğüzhan Çi̇çekoğlu, Mehmet Di̇şçi̇gi̇l

Turkish Journal of Electrical Engineering and Computer Sciences

In this work, new oscillator topologies based on a recently introduced active element, namely inverting second-generation current conveyor, are presented. This recently introduced unity gain based active element is suitable for integrated circuit realization and can easily be implemented with CMOS technology. Considering this fact, basic oscillator topologies employing a single, two and three conveyors are proposed. Several oscillator circuits based on these topologies are obtained. Expressions for oscillation conditions and frequencies are derived both for ideal and non-ideal cases. Some of them are single frequency and the others are variable frequency oscillators. The oscillators employing two and three active …

Preface, Levent Sevgi̇

Turkish Journal of Electrical Engineering and Computer Sciences

No abstract provided.

Electromagnetic Engineering In The 21^{St} Century: Challenges And Perspectives, Leopold B. Felsen, Levent Sevgi̇

Turkish Journal of Electrical Engineering and Computer Sciences

This paper aims at a broad-brush look at certain technological and educational challenges that confront wave-oriented electromagnetic (EM) engineering in the 21^{st} century, in a complex computer and technology-driven world with rapidly shifting societal and technical priorities. Simulation strategies for complex EM systems, both analytic and numerical, are reviewed and categorized, and are illustrated on selected practical complex multicomponent system scenarios currently under investigation in Turkey. Educational issues to ensure proper multidisciplinary exposure of new generations of computer-weaned students, who will have to deal with these problems, are touched upon as well.

Time-Domain Simulation Of Thin Material Boundaries And Thin Panels Using Digital Filters In Tlm, J. Paul, V. Podlozny, Dave Thomas, C. Christopoulos

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, the design and implementation of digital filters for the time-domain simulation of electromagnetic wave interaction with thin material boundaries and thin panels using the Transmission-Line Modelling (TLM) method are described. The technique is applied to the description of thin ferrite layers placed on the external boundaries of the modelled space and to plastic panels placed inside the modelled space. The approach is validated using one-dimensional examples having analytic solutions. Finally, the results obtained for the Shielding Effectiveness (SE) of a practical equipment enclosure are presented to demonstrate the utility of the method in Electromagnetic Compatibility (EMC) prediction.

Aspects Of Radar Polarimetry, Ernst Luneburg

Turkish Journal of Electrical Engineering and Computer Sciences

This contribution is a tutorial introduction to the phenomenological theory of radar polarimetry for the coherent scatter case emphasizing monostatic backscattering and forward scattering (transmission). Characteristic similarities and differences between radar polarimetry and optical polarimetry and the role of linear and antilinear operators (time-reversal) are pointed out and typical polarimetric invariants are identified.

Two-Dimensional Photonic Crystal L-Shaped Bent Waveguide And Its Application To Wavelength Multi/Demultiplexer, Yoshihiro Naka, Hiroyoshi Ikuno

Turkish Journal of Electrical Engineering and Computer Sciences

The bent waveguide is a key element for integrated optical signal processing waveguide devices. We propose a new type of two-dimensional photonic crystal L-shaped bent waveguides with additional pillars at the corner. Using the FDTD method based on the principle of multidimensional wave digital filters we simulate its transmission characteristics and show an excellent transmission of light in L-shaped bent waveguide. As an application we design compact size multi/demultiplexer composed of the L-shaped bent waveguides and directional couplers and realize multi/demultiplexer with low-insertion loss and high extinction ratio device whose size is of the order of the wavelength of light.

Discrete Array Representation Of Continuous Space-Time Source Distributions, Amir Shlivinski, Ehud Heyman

Turkish Journal of Electrical Engineering and Computer Sciences

We consider the realization of a continuous space-time source distributions using a sparse non-uniform point-source array. The construction determines the largest possible cells corresponding to the local source parameters in order to obtain a sparse array, while meeting an error criterion on the pulsed radiation pattern. The scheme is applied for the realization of collimated short-pulse beam fields. The error criterion is imposed within the main beam direction, while outside this region the relative realization error can be large but it is negligible since the field there is small compared to the main beam field.

Development Of A Cylindrical Waveguide Antenna Array With A High Isolation Between Receive - Transmit Sub Arrays: Theory And Experiment, Vladimir I. Okhmatovsky, Konstantina S. Nikita, Stavros Koulouridis, Nikolaos K. Uzunoglu

Turkish Journal of Electrical Engineering and Computer Sciences

The possibility of developing an antenna system consisting of transmit and receive arrays and being able to work simultaneously in full duplex mode at the same frequency is a very attractive task. This could only be achieved if the isolation between the transmit and receive arrays is sufficiently high not to cause a parasitic oscillation which will ruin the proper operation of a transponder system to which the arrays will be connected. Specifically, in this paper the operation of two peripheral open waveguide arrays placed on a cylindrical surface and being isolated with a radial line operating as a space …