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2004

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Articles 31 - 60 of 99

Full-Text Articles in Electrical and Electronics

Service And Network Modeling For Implementation Of Powerline Remote Monitoring Of Electrical Power Metering In Tanzania, J Anatory Jun 2004

Service And Network Modeling For Implementation Of Powerline Remote Monitoring Of Electrical Power Metering In Tanzania, J Anatory

Tanzania Journal of Engineering and Technology (TJET)

The conventional metering. pyepa.vmen,' and estimates have been used in power utilities industries. The svslen,'s hare experienced many problems such as power tampering, bill tampering, ./åiluve ro receive invoices by poner unlity customers and so on. Different technologies have been investigated To overcome the problems and recently it has been realized that remote 'nonitoring sysle•ns through powerline channel is a solution offhese problems in Tanami". However. 'he powerline network has been used for electrical power IO use i,' for implementation of remote monitoring: network must be setup and has to be modeled to accommodate communications. The contribution has analyzed 'he …


Implementing Institute Of Electrical And Electronics Engineers (Ieee) 802.11 Standard Medium Access Control Protocol For Wireless Local Area Networks (Lans) On A Laboratory Hardware Prototype, Joshua D. Green Jun 2004

Implementing Institute Of Electrical And Electronics Engineers (Ieee) 802.11 Standard Medium Access Control Protocol For Wireless Local Area Networks (Lans) On A Laboratory Hardware Prototype, Joshua D. Green

Theses and Dissertations

Wireless Local Area Networks (LANs) are extremely convenient, flexible, and easy to deploy. All LANs in which multiple hosts must access the same medium use a Medium Access Control (MAC) protocol to coordinate channel access. The MAC is part of the Data Link Layer of the Open Systems Interconnection (OSI) Reference Model. One MAC protocol in extensive use today is the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard. Since IEEE 802.11 devices are so prevalent in today s world, many researcher are exploring modifications and enhancements to the protocol. There are several well developed analytical and simulation models …


Investigation Into The Current Statistical Distribution For Oxide Breakdown Versus The Oxide Thickness Used In Integrated Circuit Manufacture, Eoin James O Driscoll Jun 2004

Investigation Into The Current Statistical Distribution For Oxide Breakdown Versus The Oxide Thickness Used In Integrated Circuit Manufacture, Eoin James O Driscoll

Theses

A critical aspect of integrated circuit manufacturing is the reliability of the components, in particular the gate oxide of transistors and capacitors. Accelerated stress tests are used for reliability predictions of gate oxides. There are two statistical distributions, which can be applied to stress test failure data, namely the Lognormal or the Weibull distributions. The failure data can fit each distribution equally well. However the use of either distribution will give vastly different lifetime predictions and their correct use is crucial for accurate lifetime prediction. A statistical based test, developed with Monte Carlo data, which is designed to decide if …


Simulation Of Hot Electron And Quantum Effects In Algan/Gan Heterostructure Field Effect Transistors, N. Braga, R. Mickevicius, R. Gaska, H. Xu, M. S. Shur, M. Asif Khan, Grigory Simin, J. Yang Jun 2004

Simulation Of Hot Electron And Quantum Effects In Algan/Gan Heterostructure Field Effect Transistors, N. Braga, R. Mickevicius, R. Gaska, H. Xu, M. S. Shur, M. Asif Khan, Grigory Simin, J. Yang

Faculty Publications

We report on simulations of electrical characteristics of AlGaN/(InGaN)/GaN heterostructurefield effect transistors with quantum and hot electroneffects taken into account. Polarization charges lead to quantum confinement of electrons in the channel and to the formation of two-dimensional electron gas. The electron quantization leads to the spread of the electronwave function into the barrier and bulk but does not have significant impact on dc electrical characteristics.Hot electrons play an important part in the charge transport by spilling over into the bulk GaN where they are captured by traps. This leads to negative differential conductivity, which is also observed experimentally. The simulation …


Performance Evaluation Of Communication Systems With Transmit Diversity, Chunjun Gao May 2004

Performance Evaluation Of Communication Systems With Transmit Diversity, Chunjun Gao

Dissertations

Transmit diversity is a key technique to combat fading with multiple transmit antennae for next-generation wireless communication systems. Space-time block code (STBC) is a main component of this technique. This dissertation consists of four parts: the first three discuss performance evaluation of STBCs in various circumstances, the fourth outlines a novel differential scheme with full transmit diversity.

In the first part, closed-form expressions for the bit error rate (BER) are derived for STBC based on Alamouti's scheme and utilizing M-ary phase shift keying (MPSK) modulation. The analysis is carried out for a slow, flat Rayleigh fading channel with coherent detection …


Multi-Rate Access Schemes And Successive Interference Cancellation For Wireless Multimedia Mc-Cdma Communications, Mizhou Tan May 2004

Multi-Rate Access Schemes And Successive Interference Cancellation For Wireless Multimedia Mc-Cdma Communications, Mizhou Tan

Dissertations

To catch up with the fast changes of the information challenges, providing multimedia services has become a very important requirement for future wireless communications. A proper system, capable of supporting multi-rate transmissions as well as handling high quality of service (QoS) requirements in hostile wireless communication environments, should be sought. Multi-carrier CDMA (MC-CDMA), a combination of multi-carrier modulation (MCM) and direct-sequence CDMA (DS-CDMA), appears to be one of the most elegant solutions. In this dissertation, four multi-rate access schemes, termed uncoded fixed spreading length (UFSL), coded fixed spreading length (CFSL), multi-code fixed spreading length (MFSL) and variable spreading length (VSL), …


Providing Guaranteed Qos In The Hose-Modeled Vpn, Dong Wei May 2004

Providing Guaranteed Qos In The Hose-Modeled Vpn, Dong Wei

Dissertations

With the development of the Internet, Internet service providers (ISPs) are required to offer revenue-generating and value-added services instead of only providing bandwidth and access services. Virtual Private Network (VPN) is one of the most important value-added services for ISPs.

The "classical" VPN service is provided by implementing layer 2 technologies, either Frame Relay (FR) or Asynchronous Transfer Mode (ATM). With FR or ATM, virtual circuits are created before data delivery. Since the bandwidth and buffers are reserved, the QoS requirements can be naturally guaranteed. In the past few years, layer 3 VPN technologies are widely deployed due to the …


Phase Noise Effects On Ofdm : Analysis And Mitigation, Songping Wu May 2004

Phase Noise Effects On Ofdm : Analysis And Mitigation, Songping Wu

Dissertations

Orthogonal frequency division multiplexing (OFDM) is a promising technique which has high spectrum efficiency and the robustness against channel frequency selectivity. One drawback of OFDM is its sensitivity to phase noise. It has been shown that even small phase noise leads to significant performance loss of OFDM. Therefore, phase noise effects on OFDM systems need to be analyzed and methods be provided to its mitigation.

Motivated by what have been proposed in the literature, the exact signal to interference plus noise ratio (SINR) is derived in this dissertation for arbitrary phase noise levels. In a multiple access environment with multiple …


Enhancing Qos Provisioning And Granularity In Next Generation Internet, Jie Yang May 2004

Enhancing Qos Provisioning And Granularity In Next Generation Internet, Jie Yang

Dissertations

Next Generation IP technology has the potential to prevail, both in the access and in the core networks, as we are moving towards a multi-service, multimedia and high-speed networking environment. Many new applications, including the multimedia applications, have been developed and deployed, and demand Quality of Service (QoS) support from the Internet, in addition to the current best effort service. Therefore, QoS provisioning techniques in the Internet to guarantee some specific QoS parameters are more a requirement than a desire. Due to the large amount of data flows and bandwidth demand, as well as the various QoS requirements, scalability and …


Statistical Anomaly Denial Of Service And Reconnaissance Intrusion Detection, Zheng Zhang May 2004

Statistical Anomaly Denial Of Service And Reconnaissance Intrusion Detection, Zheng Zhang

Dissertations

This dissertation presents the architecture, methods and results of the Hierarchical Intrusion Detection Engine (HIDE) and the Reconnaissance Intrusion Detection System (RIDS); the former is denial-of-service (DoS) attack detector while the latter is a scan and probe (P&S) reconnaissance detector; both are statistical anomaly systems.

The HIDE is a packet-oriented, observation-window using, hierarchical, multi-tier, anomaly based network intrusion detection system, which monitors several network traffic parameters simultaneously, constructs a 64-bin probability density function (PDF) for each, statistically compares it to a reference PDF of normal behavior using a similarity metric, then combines the results into an anomaly status vector that …


Ad Hoc Network Security And Modeling With Stochastic Petri Nets, Congzhe Zhang May 2004

Ad Hoc Network Security And Modeling With Stochastic Petri Nets, Congzhe Zhang

Dissertations

Advances in wireless technology and portable computing along with demands for high user mobility have provided a major promotion toward the development of ad hoc networks. These networks feature dynamic topology, self-organization, limited bandwidth and battery power of a node. Unlike the existing commercial wireless systems and fixed infrastructure networks, they do not rely on specialized routers for path discovery and traffic routing. Security is an important issue in such networks. Typically, mobile nodes are significantly more susceptible to physical attacks than their wired counterparts.

This research intends to investigate the ad hoc network routing security by proposing a performance …


Qos Provisioning In Multimedia Streaming, Hong Zhao May 2004

Qos Provisioning In Multimedia Streaming, Hong Zhao

Dissertations

Multimedia consists of voice, video, and data. Sample applications include video conferencing, video on demand, distance learning, distributed games, and movies on demand. Providing Quality of Service (QoS) for multimedia streaming has been a difficult and challenging problem. When multimedia traffic is transported over a network, video traffic, though usually compressed/encoded for bandwidth reduction, still consumes most of the bandwidth. In addition, compressed video streams typically exhibit highly variable bit rates as well as long range dependence properties, thus exacerbating the challenge in meeting the stringent QoS requirements of multimedia streaming with high network utilization. Dynamic bandwidth allocation in which …


Ultra-Wideband Technology For Short-Range Wireless Communication, Li Zhao May 2004

Ultra-Wideband Technology For Short-Range Wireless Communication, Li Zhao

Dissertations

The ultra-wideband (UWB) radio core idea is to open large amounts of spectrum to a variety of users with little mutual interference between them. While ultra-wideband is being championed by several commercial companies, this technology has not followed the conventional path where commercial interest is preceded by years of academic research. This work attempts to fill in some of the gap by studying fundamental properties of communications with impulse-based radio UWB signals. We study jam resistance and capacity of UWB. Jam resistance is analyzed for binary pulse position modulation (PPM) with the interference being modeled as correlated Gaussian. Closed-form expressions …


Transmission And Detection For Space-Time Block Coding And V-Blast Systems, Lei He May 2004

Transmission And Detection For Space-Time Block Coding And V-Blast Systems, Lei He

Dissertations

This dissertation focuses on topics of data transmission and detection of space -time block codes (STBC). The STBCs can be divided into two main categories, namely, the orthogonal space-time block codes (OSTBC) and the quasi-orthogonal space-time codes (Q-OSTBC). The space-time block coded systems from transceiver design perspective for both narrow-band and frequency selective wireless environment are studied. The dissertation also processes and studies a fast iterative detection scheme for a high-rate space-time transmission system, the V-BLAST system.

In Chapter 2, a new OSTBC scheme with full-rate and full-diversity, which can be used on QPSK transceiver systems with four transmit antennas …


Hybrid Routing And Bridging Strategies For Large Scale Mobile Ad Hoc Networks, Sheng Xu May 2004

Hybrid Routing And Bridging Strategies For Large Scale Mobile Ad Hoc Networks, Sheng Xu

Dissertations

Multi-hop packet radio networks (or mobile ad-hoc networks) are an ideal technology to establish "instant" communication infrastructure for military and civilian applications in which both hosts and routers are mobile. In this dissertation, a position-based/link-state hybrid, proactive routing protocol (Position-guided Sliding-window Routing - PSR) that provides for a flat, mobile ad-hoc routing architecture is described, analyzed and evaluated. PSR is based on the superposition of link-state and position-based routing, and it employs a simplified way of localizing routing overhead, without having to resort to complex, multiple-tier routing organization schemes. A set of geographic routing zones is defined for each node, …


A Statistical Ultra Wideband Indoor Channel Model And The Effects Of Antenna Directivity On Multipath Delay Spread And Path Loss In Ultra Wideband Indoor Channels, Jason Anthony Dabin May 2004

A Statistical Ultra Wideband Indoor Channel Model And The Effects Of Antenna Directivity On Multipath Delay Spread And Path Loss In Ultra Wideband Indoor Channels, Jason Anthony Dabin

Theses

Ultra-wideband (UWB) indoor frequency domain channel measurements have been performed in the 2 GHz to 6 GHz frequency band using three different transmitter/receiver (Tx/Rx) antenna combination pairs. The effects of antenna directivity on path loss and multipath propagation in the channel were analyzed extensively for various omni-directional and directional antenna combinations. A statistical model of the path loss in the channel is presented, where the parameters in the model (i.e., path loss exponent and shadow fading statistics) are dependent on the particular Tx/Rx antenna combination. Time domain statistics of the channel (i.e., mean delay spread and RMS delay spread) are …


Si-Sio2 Interface Behavior In N-Mosfets With Screening Potential During High-Field Injection, Purushothaman Srinivasan May 2004

Si-Sio2 Interface Behavior In N-Mosfets With Screening Potential During High-Field Injection, Purushothaman Srinivasan

Theses

This work investigates the screening of hot carrier stress degradation in n-channel MOSFETs when the devices were exposed to plasma processing. Devices with various antenna ratios were subjected to current stress (both gate injection and substrate injection) while the source and drain terminals were reverse biased by a screening potential followed by hot carrier stress. It was observed that screening of the drain edge was effective for both gate injection and substrate injection at different screening potentials. The hot carrier lifetime is directly related to interface state density (Dit), measured by charge pumping method. The results suggest that hot electron …


Study Of Design Tradeoffs Of Dram And Sram Memories, Using Hspice Computer Simulation, Bageshri Kale May 2004

Study Of Design Tradeoffs Of Dram And Sram Memories, Using Hspice Computer Simulation, Bageshri Kale

Theses

Semiconductor random access memories are complex systems that can be described by performance parameters such as memory cycle time, access delays, storage capacity, bit packing density, chip area and retention time. In this thesis, tradeoffs between cycle time, chip area, and storage size as reflected by bit line capacitance (Cbl) were studied as a function of particular design variables: memory cell capacitance (Cc); CMOS flip-flop sense amplifier (SA) transistor sizes; and size of precharge (PC), and word line (WL) switches. Performance was optimized using circuit simulation software, HSPICE, to observe DRAM and SRAM waveforms. With TSMC 0.18 micron technology, minimum …


Investigation Of Nanoporous Thin-Film Alumina Templates, Biswajit Das May 2004

Investigation Of Nanoporous Thin-Film Alumina Templates, Biswajit Das

Electrical & Computer Engineering Faculty Research

This paper presents the results of a systematic study of the fabrication of thin-film alumina templates on silicon and other substrates. Such templates are of significant interest for the low-cost implementation of semiconductor and metal nanostructure arrays. In addition, thin-film alumina templates on silicon have the potential for nanostructure integration with silicon electronics. Formation of thin-film alumina templates on silicon substrates was investigated under different fabrication conditions, and the dependence of pore morphology and pore formation rate on process parameters was evaluated. In addition, process conditions for improved pore size distribution and periodicity were determined. The template/silicon interface, important for …


Analysis Of Kancil's Car Knuckle Prototype, Tresna P. Soemardi, Aida Mahmudah Apr 2004

Analysis Of Kancil's Car Knuckle Prototype, Tresna P. Soemardi, Aida Mahmudah

Makara Journal of Technology

Analysis of Kancil’s Knuckle Prototype. The objective of this work is to execute strength analysis of knuckle, which is made from FCD 50, by using static analysis on maximum loading. This maximum loading is obtained from front axle loading calculation on particular operating condition. That is, vehicle is braking while cornering in down hill. From previous vehicle loading calculation, we get a number of loading values on different speed and deceleration. At the end, we get a value of speed and deceleration that guarantee the vehicle safety if it is braking while cornering in down hill. As comparison, loading calculation …


Pid Fuzzy Logic Controller System For Dc Motor Speed Control, H. Samsul Bachri M. Apr 2004

Pid Fuzzy Logic Controller System For Dc Motor Speed Control, H. Samsul Bachri M.

Makara Journal of Technology

PID Fuzzy Logic Controller System for DC Motor Speed Control. A good controller system must have resilience to disturbance and must be able to response quickly and accurately. Problem usually appears when PID controller system was built sensitively hence the system’s respon to the disturbance will yield big overshot/undershot then the possibility of oscillation to be happened is excelsior. When the controller system was built insensitively, the overshot/undershot will be small but the recovery time will be longer. Hybrid controller system could overcome those problems by combining PID control system with fuzzy logic. The main control of this system is …


Quarternair Cugasete And Cuga0.5in 0.5te2 Thin Films Fabrication Using Flash Evaporation, A. Harsono Soepardjo Apr 2004

Quarternair Cugasete And Cuga0.5in 0.5te2 Thin Films Fabrication Using Flash Evaporation, A. Harsono Soepardjo

Makara Journal of Technology

Quarternair CuGaSeTe and CuGa0.5In 0.5Te2 Thin Films Fabrication Using Flash Evaporation. Quarternair materials CuGaSeTe and CuGa0.5In 0.5Te2 are the basic materials to solar cell fabrication. These materials have high absorption coefficients around 103 – 105 cm-1 and band gap energy in the range of 1-5 eV. In this research, the films were made by flash evaporation method using quarternair powder materials of CuGaSeTe and CuGa0.5In 0.5Te2 to adhere in a glass substrate. After the films were obtained, the properties of these films will be characterized optically and electrically. The lattice parameter of the films and the crystalline film structure were …


Graded Channel Mosfet Simulation With S-Pisces 2b, Hartono Siswono Apr 2004

Graded Channel Mosfet Simulation With S-Pisces 2b, Hartono Siswono

Makara Journal of Technology

Graded Channel MOSFET simulation with S-Pisces 2B. Graded-Channel Metal-Oxide-Semiconductor Field-effect- Transistor or GCMOSFET is being discussed in this paper. GCMOSFET technology has been developed to meet the growing demand for low power and high performance application. In this paper, it will be shown that, compared to ungraded MOSFET, the GCMOSFET device offers the advantage of significantly higher drive current. The higher drive current is achieved because the effecctive channel length of GCMOSFET is shorter than the ungraded MOSFET’s. From the simulation result with S-PISCES 2B and MATLAB, it can been shown that the ID from GCMOSFET is higher than the …


Construction Of Depth-Structure Shelf-Edge Map For Case Study Of Kujung Formation, East Java Sea, Saifatur Rusli, Suparto Suparto Apr 2004

Construction Of Depth-Structure Shelf-Edge Map For Case Study Of Kujung Formation, East Java Sea, Saifatur Rusli, Suparto Suparto

Makara Journal of Technology

Construction of Depth-Structure Shelf-edge Map for Case Study of Kujung Formation, East Java Sea. In general, reflection seismic method has capability to represent sub-surface in time domain. Seismic cross-section that depicts the formation of sub-surface usually use time domain in the format of TWT (Two Way Times). This due to in the process of seismic data acquisition, seismic wave propagates in down-going and up-going manner so that the obtained results from data processing are in the format of TWT seismic vs. shot points. This paper will describe the construction of depth-structure map for case study of Kujung Formation, East Java …


Evaluating The Navigation Potential Of The National Television System Committee Broadcast Signal, Ryan J. Eggert Mar 2004

Evaluating The Navigation Potential Of The National Television System Committee Broadcast Signal, Ryan J. Eggert

Theses and Dissertations

The accuracy and worldwide availability of the Global Positioning System (GPS) make it the dominant system for navigation and precise positioning. Unfortunately, many situations arise in which GPS may not be adequate, e.g., urban navigation. This research evaluates the navigation potential of the National Television System Committee (NTSC) broadcast signal using a time-difference-of-arrival (TDOA) algorithm. TDOA measurements are made using NTSC broadcast signals collected from low and high multipath environments. These measurements are then used to evaluate the severity and dynamic effects of NTSC broadcast multipath signals. Three data reduction algorithms were developed--one that modifies the classical cross-correlation TDOA approach, …


Simulating A Chromotomographic Sensor For Hyperspectral Imaging In The Infrared, Anthony J. Dearinger Mar 2004

Simulating A Chromotomographic Sensor For Hyperspectral Imaging In The Infrared, Anthony J. Dearinger

Theses and Dissertations

Hyperspectral imaging systems passively sense radiant electromagnetic energy from a remote scene to form a three dimension profile of the remote scene. The data contained in this profile describes real images of the remote scene for a certain number of spectral wavelength bands across a finite spectral range of electromagnetic radiation. Typical grating type hyperspectral imaging systems collect spectral electromagnetic radiation in the visible and near infrared spectral range, by incrementally scanning across the spatial extent of the remote scene. The legacy of low optical throughput because of the optical scanning techniques employed in these systems means adapting these systems …


Multiple Access Interference Characterization For Direct-Sequence Spread-Spectrum Communications Using Chip Waveform Shaping, Matthew G. Glen Mar 2004

Multiple Access Interference Characterization For Direct-Sequence Spread-Spectrum Communications Using Chip Waveform Shaping, Matthew G. Glen

Theses and Dissertations

This research characterizes MAI effects on DS/SSMA system performance through simulation in Matlab , and explores the impact of multiple access code selection, chip waveform shaping, and multiple access code length on BER for both synchronous and asynchronous multiple access networks. In addition, the simulated DS/SSMA model permits rapid research into the effects of additional factors on BER. Prior to experimental testing, model validation is conducted through single user trials and by comparison with existing research for similar system designs. For synchronous and asynchronous networks, Gold coding improves BER by 7.5 and 4.0 dB, respectively, relative to aperiodic random spreading …


Discovering The Merit Of The Wavelet Transform For Object Classification, Matthew D. Eyster Mar 2004

Discovering The Merit Of The Wavelet Transform For Object Classification, Matthew D. Eyster

Theses and Dissertations

Vision is the primary sense by which most biological systems collect information about their environment. Computer vision is a branch of artificial intelligence concerned with endowing machines with the ability to understand images. Object recognition is a key part of machine vision with far reaching benefits ranging from target recognition, surveillance systems, to automation systems. Extraction of salient features from an image is one of the key steps in object recognition. Typically, geometric primitives are extracted from an image using local analysis. However, the wavelet transform provides a global approach with good locality. Additionally, the directional and multiresolution properties may …


Characterization Of Ultra Wideband Multiple Access Performance Using Time Hopped-Biorthogonal Pulse Position Modulation, Donald J. Clabaugh Mar 2004

Characterization Of Ultra Wideband Multiple Access Performance Using Time Hopped-Biorthogonal Pulse Position Modulation, Donald J. Clabaugh

Theses and Dissertations

The FCC's release of its UWB First Report and Order in April 2002 spawned renewed interest in impulse signaling research. This work combines Time Hopped (TH) multiple access coding with 4-ary UWB Biorthogonal Pulse Position Modulation (TH-BPPM). Multiple access performance is evaluated in a multipath environment for both synchronous and asynchronous networks. Fast time hopping is implemented by replicating and hopping each TH-BPPM symbol NH times. Bit error expressions are derived for biorthogonal TH-BPPM signaling and results compared with previous orthogonal TH-PPM work. Without fast time hopping (NH = 1), the biorthogonal TH-BPPM technique provided gains equivalent to Gray-coded QPSK; …


Atmospheric Simulation Using A Liquid Crystal Wavefront Controlling Device, Matthew R. Brooks Mar 2004

Atmospheric Simulation Using A Liquid Crystal Wavefront Controlling Device, Matthew R. Brooks

Theses and Dissertations

Test and evaluation of laser warning devices is important due to the increased use of laser devices in aerial applications. In this thesis, an atmospheric aberrating system is developed to enable in-lab testing of laser warning devices. This system employs laser light at 632.8nm from a Helium-Neon source and a spatial light modulator (SLM) to cause phase changes using a birefringent liquid crystal material. Before the system can be used, the SLM phase response must be quantified to ensure proper manipulation of index of refraction. Additionally, diffraction from the SLM and real-world system scaling are addressed. Once completed, the atmospheric …