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Articles 541 - 570 of 587

Full-Text Articles in Engineering

Statistical Properties Of Composite Distortions In Hfc Systems And Their Effects On Digital Channels, Ron D. Katznelson May 2002

Statistical Properties Of Composite Distortions In Hfc Systems And Their Effects On Digital Channels, Ron D. Katznelson

Ron D. Katznelson

The statistical properties of Composite Triple Beat (CTB) and Composite Second Order (CSO) distortion terms associated with the analog channels carried on Hybrid Fiber Coax (HFC) are presented. Both simulation and measurement results show that such distortion components falling on individual channels have amplitude Probability Density Function that is nearly Rayleigh distributed (having a Standard Deviation of 5.7 dB). It is shown that both CTB and CSO components have peak envelope power fluctuations that exceed their average (measured) power levels by more than 15 dB. The temporal statistical properties of these distortion components demonstrate peak envelope power fluctuations with characteristic …


Pattern-Sensitive Deposition For Damascene Processing, M Hussein, A Myers, Charles H. Recchia, S Sivakumar, A Kandas Jan 2002

Pattern-Sensitive Deposition For Damascene Processing, M Hussein, A Myers, Charles H. Recchia, S Sivakumar, A Kandas

Charles H Recchia

No abstract provided.


Using Prior Information In The Structure Selection Of Rbf Network Models, Gladstone B. Alves, Marcelo V. Corrêa Jan 2002

Using Prior Information In The Structure Selection Of Rbf Network Models, Gladstone B. Alves, Marcelo V. Corrêa

Gladstone B. Alves

No abstract provided.


Searching For Dynamical Resemblance Between Time Series - A Method Based On Nonlinear Autoregressive Models, Gladstone B. Alves, Marcelo V. Corrêa, Viviane C. Silva Jan 2002

Searching For Dynamical Resemblance Between Time Series - A Method Based On Nonlinear Autoregressive Models, Gladstone B. Alves, Marcelo V. Corrêa, Viviane C. Silva

Gladstone B. Alves

No abstract provided.


A Neural Network-Based Approach For Control Of Capacitors Installed On Distribution Systems For Power Loss Reduction, Almoataz Youssef Abdelaziz Dec 2001

A Neural Network-Based Approach For Control Of Capacitors Installed On Distribution Systems For Power Loss Reduction, Almoataz Youssef Abdelaziz

Almoataz Youssef Abdelaziz

A neural network for capacitor switching in electric distribution systems for the purpose of power loss reduction is presented in this paper. An optimization technique (sensitive node method) for allocating the compensating capacitors is used to generate the training set patterns of the neural network. The required input data of the neural network at varying loading conditions are directly obtained from a load flow study of the distribution system. Load variations are assumed to follow a randomized function that generates a randomized matrix which is employed for implementing the different load levels. The developed neural network is based on a …


Development Of Hiv Model And Its Simulation, D. K. Chaturvedi, Pritam Singh, S. K. Gaur, D. S. Mishra Dec 2001

Development Of Hiv Model And Its Simulation, D. K. Chaturvedi, Pritam Singh, S. K. Gaur, D. S. Mishra

D. K. Chaturvedi Dr.

The article discusses model developmetn for HIV infected population using the System Dynamics technique. The technique has an advantage over conventional modeling technique as it is dependent more on causal relationships that involve qualitative and quantitative variables to model socioeconomic problems of a complex nature. The model has been simulated and the results haven been compared witht he available data.


Artificial Neural Network Learning Using Improved Genetic Algorithms, D. K. Chaturvedi Nov 2001

Artificial Neural Network Learning Using Improved Genetic Algorithms, D. K. Chaturvedi

D. K. Chaturvedi Dr.

The feedforward back-propagation artificial neural networks (ANN) are widely used to control the various industrial process, for modelling, simulation of systems and forecasting. The backpropagation learning has various drawbacks such as slowness in learning, stuck in local minima, requies functional derivative of aggregation function and thresholding function to minimize error function. Various researchers have suggested a number of improvement in simple back-propagation learning algorithm developed by Widrow and Holf in 1956. In this paper, a program is developed for feedforward artificial neural network with genetic algorithm (GA) as the learning mechanism to overcome some of the disadvantages of back-propagation learning …


Fuzzified Neural Network Approach For Load Forecasting Problems, D. K. Chaturvedi, P. S. Satsangi, P. K. Kalra Mar 2001

Fuzzified Neural Network Approach For Load Forecasting Problems, D. K. Chaturvedi, P. S. Satsangi, P. K. Kalra

D. K. Chaturvedi Dr.

In load forecasting, the operator or the concerned person uses his or her experience and intuitions to obtain a good guess of the load demand. This guess is normally supported by sophisticated mathematical prediction techniques. The short term load not only varies from hour to hour, but is also influenced by the nature of events, load demand, the type of the load considered, seasonal variations, weekend day or holidays, and also by sudden demand and loss of load. Accordingly, it is quite clear that the electrical load-forecasting problem is quite difficult to model with mathematical difference or differential equations. In …


Design Approach To Use Platinum Rtd Sensor In Snow Temperature Measurements, Raman Attri Jan 2001

Design Approach To Use Platinum Rtd Sensor In Snow Temperature Measurements, Raman Attri

Raman K. Attri

The snow temperature measurement is a very critical area of hydrological instrumentation. The measured data is used to assess the run-off water, snow pack strength and snow avalanche. The hydrological and snow avalanche forecast models require that temperature be measured at different points in the snow pack, above the snow pack and below the snow pack. A state-of-the-art multi-point snow temperature measurement system has been designed and developed for this purpose. The type of the temperature sensor used is a critical aspect of this physical parameter instrumentation. After lot of study of various aspects of different temperature sensing elements, the …


Use Of Energy And Power Concepts In The Analysis Of The Inter-Area Mode Phenomenon, Arturo Roman Messina Jan 2001

Use Of Energy And Power Concepts In The Analysis Of The Inter-Area Mode Phenomenon, Arturo Roman Messina

A. R. Messina

This paper presents an energy-based small signal method of analyzing low-frequency inter-area oscillations. A comprehensive framework for the analysis of system oscillations is developed based on the analysis of energy relationships in the linear state representation of the power system. This approach provides insight into the nature of the inter-area phenomenon and can be used in conjunction with modern techniques for spectral analysis of complex power systems. The practical use of the proposed methodology is tested on a complex 46-machine, 190-bus test system. Detailed non-linear time domain simulations and frequency domain studies are finally conducted to check the validity of …


Introdução Ao Hardware Evolutivo, Gladstone B. Alves Jan 2001

Introdução Ao Hardware Evolutivo, Gladstone B. Alves

Gladstone B. Alves

In the 1950's, the idea of simulate the workings of natural evolution in an engineering setting gave birth to the domain of evolutionary computation, a powerful approach to optimization and non-deterministic problem solving. Now, some researchers are beggining to create hardware that can grow and improve itself over time, evolving steadily as it finds new and better ways to do the tasks it has set before it. The field, known as Evolvable Hardware, is a recent focus of a growing endeavour to build this kind of autonomous, adaptive, and fault-tolerant electronic systems. This paper motivates current research on Evolvable Hardware …


Using Linear Arx Terms In Rbf Network Models: A Case Study Employing A Thermal Process, Gladstone B. Alves, Luis A. Aguirre, Marcelo V. Corrêa Jan 2001

Using Linear Arx Terms In Rbf Network Models: A Case Study Employing A Thermal Process, Gladstone B. Alves, Luis A. Aguirre, Marcelo V. Corrêa

Gladstone B. Alves

No abstract provided.


The Glass Bead Game, David D. Nolte Jan 2001

The Glass Bead Game, David D. Nolte

David D Nolte

Our lives are filled with images. Everyday we see signals, read signs, and learn symbols.We find our way with maps, look for news and bargains in newspapers, calculate ourbills and taxes. We turn printed music into wonderful sounds, often without consciouseffort. Icons fill our churches, synagogues and mosques, dot our computer screens, andare sprawled on billboards, on clothing and advertisement pages. Architecture and artconspire to fill our views with meaningful shapes and form. Pictures capture an instant intime, while movies and video entertain us with visual motion. We live in a visual world,full of information transmitted by light.


The Age Of Entanglement Jan 2001

The Age Of Entanglement

David D Nolte

Quantum mechanics is a venerable field of study. The year 2000 marked the 100th anniversary of theoriginal quantum hypothesis proposed by Max Planck in November of 1900. Few current fields in physicsor engineering are as old as quantum mechanics. It predates relativity, both special and general. It predatesnuclear and particle physics. Quantum mechanics even predates universal acceptance of the molecularhypothesis, that is, that all matter is made up of individual molecules in thermal motion. It may be hard tobelieve, but this happened only after Einstein's paper on Brownian motion was published in his miracleyear 1905.


Data Communication Software- Role And Functions, Raman K. Attri, Noor Jahan Haque Apr 2000

Data Communication Software- Role And Functions, Raman K. Attri, Noor Jahan Haque

Raman K. Attri

The shifting of communication systems from analog to digital has introduces a new area of data communication. The core of data communication is Communication software which is the topic of my paper today. In this paper I shall cover following areas: Overview of Data Communication, Role of Data Communication Software, Functional Aspects of Data Communication Software


A Fuzzy Logic Classifier For Transient Stability Assessment, Almoataz Youssef Abdelaziz Mar 2000

A Fuzzy Logic Classifier For Transient Stability Assessment, Almoataz Youssef Abdelaziz

Almoataz Youssef Abdelaziz

Transient stability assessment (TSA) of a power system pursues a two-fold objective: first to appraise the system’s capability to withstand major contingencies and second to suggest remedial actions whenever needed. The first objective is the concern of analysis; the second is a matter of control. To assess transient stability, multitude of techniques are available encompassing traditional time domain state numerical integration, Lyapunov based techniques, probabilistic methods, and recently Artificial Intelligence (AI) techniques. This paper presents a simple but effective fuzzy logic classifier system for TSA. The fuzzy logic-based rule assessment needs only a fraction of time to solve the classification …


An Adaptive Protection Scheme For Optimal Overcurrent Relay Coordination In Interconnected Power Systems, Almoataz Youssef Abdelaziz Mar 2000

An Adaptive Protection Scheme For Optimal Overcurrent Relay Coordination In Interconnected Power Systems, Almoataz Youssef Abdelaziz

Almoataz Youssef Abdelaziz

This paper presents an adaptive protection scheme for optimal coordination of overcurrent relays (OCR) in interconnected power networks with an improved formulation. The scheme adapts to system changes; new relays settings are implemented as load, generation-level or system-topology changes. The software developed for this application is described. The developed scheme is applied to the IEEE 30-bus test system. Results showed the importance and necessity of this scheme in maintaining the optimal performance of the relays in all conditions.


Software Tool For Seismic Data Recorder And Analyser, Satish Kumar, Raman Attri, B. Sharma, M. Shamshi Jan 2000

Software Tool For Seismic Data Recorder And Analyser, Satish Kumar, Raman Attri, B. Sharma, M. Shamshi

Raman K. Attri

Design and Development of software controlled stand-alone instruments has been identified as the most vital component of national and intemational programs on earthquake hazard and risk management. For in depth investigation and studies, the development of precise instruments designed around computer is emerging very fast. Interacing of personal computer with seismic instrument is an important design task. A design technique based on minimum hardware has been worked out around the parallel printer interface of computer. Hardware and Software for this purpose has been designed to make the instrument interact with computer through parallel port interface. Incorporation of software for seismic …


Knowledge Based Neural Network For Voltage Contingency Selection And Ranking, Sn Singh, L Srivastava, Jd Sharma Nov 1999

Knowledge Based Neural Network For Voltage Contingency Selection And Ranking, Sn Singh, L Srivastava, Jd Sharma

SN Singh PhD

No abstract provided.


Load Frequency Control: A Generalized Neural Network Approach, D. K. Chaturvedi, P. S. Satsangi, P. K. Kalra Sep 1999

Load Frequency Control: A Generalized Neural Network Approach, D. K. Chaturvedi, P. S. Satsangi, P. K. Kalra

D. K. Chaturvedi Dr.

Variation in load frequency is an index for normal operation of power systems. When load perturbation takes place anywhere in any area of the system, it will affect the frequency at other areas also. To control load frequency of power systems various controllers are used in different areas. but due to non-linearities in the system components and alternators, these controllers cannot control the frequency quickly and efficiently. Simple neural networks which are in common use at present have various drawbacks like large training time, requirement of large number of neurons, etc. The present work deals with the developmetn of a …


Design Of An Instrumentation System To Record Distribution Profile Of Snow Layer Temperature For Modelling Of Snow Avalanche Forecast, Raman Attri Aug 1999

Design Of An Instrumentation System To Record Distribution Profile Of Snow Layer Temperature For Modelling Of Snow Avalanche Forecast, Raman Attri

Raman K. Attri

The measurement of snow hydrological parameters is extremely important in developing a model for the predication of Snow avalanche as well as Snowmelt water in the rivers. When direct measurement of these parameters is practically difficult, its dependence on snow temperature is used to develop snow cover models. A robust model for avalanche forecasting requires a sophisticated instrumentation system which can measure the required temperature parameters at right data points within snow pack. A Snow Temperature Profile Sensing System along with Surface temperature Sensor has been designed to measure Snow temperature gradient, temperature distributions, and average temperature of snow pack, …


Implementation Of Linear Array Of Ultrasonic Transmitter-Receiver Transducers For Detection Of Non-Smooth Porous Surface, Raman K. Attri, Swaranjit Singh Jul 1999

Implementation Of Linear Array Of Ultrasonic Transmitter-Receiver Transducers For Detection Of Non-Smooth Porous Surface, Raman K. Attri, Swaranjit Singh

Raman K. Attri

Level measurements, thickness measurement or remote surface detection using ultrasonic pulse transit method require that the target surface be at 90O to the incident beam so that reflected beam comes back at 180O angel to effectively use this method. This is perfectly true in case of flat, solid surface at right angle to the incident beam. But surface irregularities of a porous, non-smooth, uneven material such as snow cause penetration of incident wave into the surface, absorption of the incident energy, scatter of energy in many directions and further attenuation of reflected signal making it difficult to detect the reflected …


Gsis: A Conceptual Model For Web-Based Integration Of Information Technology With Geo-Scientific Instrumentation, Raman Attri Jun 1999

Gsis: A Conceptual Model For Web-Based Integration Of Information Technology With Geo-Scientific Instrumentation, Raman Attri

Raman K. Attri

Since a long time leading organisations have been advocating the need of implementation of IT in a centralised manner on the distributed geological data monitoring centres. In the era of IT, it is highly important to access, share and analyse related data on a common platform for fast retrieval of information in centralised as well as in distributed mode. In this article a concept to integrate Geo-Scientific Instrumentation systems to Information Technology has been highlighted. The vision to create a Geo-Scientific Information System (GSIS) would be an approach where a centralised web-enabled database of the data acquired & transmitted by …


Analytical Investigation Of The Use Of Static Var Compensators To Aid Damping Of Inter-Area Oscillations, Arturo Roman Messina Jan 1999

Analytical Investigation Of The Use Of Static Var Compensators To Aid Damping Of Inter-Area Oscillations, Arturo Roman Messina

A. R. Messina

A comprehensive investigation of the use of Static VAR Compensators (SVCs) to aid damping of low-frequency inter-area oscillations in large interconnected power systems is presented. The study of inter-area oscillations and the design of controls is done using modal analysis of a linearized model of the power system. Based on this model an efficient algorithm to compute the power oscillation flow for each mode of concern is developed. This approach allows to identify the nature of oscillation patterns and provides important information needed in the application of SVCs. Controllability and observability measures are then used to assess the impact of …


Field-Programmable Smart-Pixel Arrays: Design, Vlsi Implementation, And Applications, Sherif S. Sherif, Stefan K. Griebel, Albert Au, Dennis Hui, Ted H. Szymanski, Harvard Scott Hinton Jan 1999

Field-Programmable Smart-Pixel Arrays: Design, Vlsi Implementation, And Applications, Sherif S. Sherif, Stefan K. Griebel, Albert Au, Dennis Hui, Ted H. Szymanski, Harvard Scott Hinton

H. Scott Hinton

A smart-pixel array is a two-dimensional array of optoelectronic devices that combine optical inputs and outputs with electronic processing circuitry. A field-programmable smart-pixel array (FP-SPA) is a smart-pixel array capable of having its electronic functionality dynamically programmed in the field. Such devices could be used in a diverse range of applications, including optical switching, optical digital signal processing, and optical image processing. We describe the design, VLSI implementation, and applications of a first-generation FP-SPA implemented with the 0.8-μm complementary metal-oxide semiconductor–self-electro-optic effect device technology made available through the Lucent Technologies–Advanced Research Projects Agency Cooperative (Lucent/ARPA/COOP) program. We report spice simulations …


Transient Stability Estimation Using Artificial Intelligence Methodology: An Inductive Inference Approach, Almoataz Youssef Abdelaziz Dec 1998

Transient Stability Estimation Using Artificial Intelligence Methodology: An Inductive Inference Approach, Almoataz Youssef Abdelaziz

Almoataz Youssef Abdelaziz

Many techniques are used for Transient Stability (TS) estimation of synchronous generators encompassing traditional time domain state numerical integration, Lyapunov based methods, probabilistic approaches and Artificial Intelligence (AI) techniques like pattern recognition and recently neural networks. This paper examines another recently proposed artificial intelligence technique to tackle the transient stability problem. The technique is based on the Inductive Inference Reasoning approach which belongs to a particular family of Machine Learning from Examples. Not only steady state but transient attributes are also used for transient stability estimation so as to reflect machine dynamics and network changes due to faults. The approach …


A Fuzzy Simulation Model Of Basic Commutating Electrical Machines, D. K. Chaturvedi, P. S. Satsangi, P. K. Kalra Dec 1998

A Fuzzy Simulation Model Of Basic Commutating Electrical Machines, D. K. Chaturvedi, P. S. Satsangi, P. K. Kalra

D. K. Chaturvedi Dr.

Fuzzy Logic as applied to a great extent in controlling the process, plants and various complex systems, due to its inherent advantages like simplicity, ease in design, robustness and adaptivity. Aslo it is established that this approach works very well especially when the systems are not transparent. In this paper the approach is used for the modelling and simulation of an electrical machine to predict the behaviour of the machine under running conditionsas well as unde starting conditions. The starting characteristics of electrical machines are non-linear in nature, and it is very difficult to model them accurately. Also the developed …


Development Of The Industrial Expert System And Its Application For The Rational Choice Of Crushing And Grinding Facilities Of A Cement Factory (Développement Du Système Expert Industriel Et Son Application Pour Le Choix Rationnel Des Installations De Concassage Et De Broyage D'Une Cimenterie), Boukhemis Chetate , Cherif Kara, Galina Tcheremechko, Irina Merazka Sep 1998

Development Of The Industrial Expert System And Its Application For The Rational Choice Of Crushing And Grinding Facilities Of A Cement Factory (Développement Du Système Expert Industriel Et Son Application Pour Le Choix Rationnel Des Installations De Concassage Et De Broyage D'Une Cimenterie), Boukhemis Chetate , Cherif Kara, Galina Tcheremechko, Irina Merazka

Boukhemis Chetate

Les économies d’énergie électrique suscitent un intérêt croissant dans le domaine de l’industrie des matériaux de construction. En effet, la dépense en électricité peut représenter jusqu’à 50% de l’ensemble des coûts d’énergie nécessaires à la fabrication d’une tonne de ciment. Par ailleurs, environ 80% de l’énergie utilisée pour la fabrication d’une tonne de ciment est dépensée pour la fragmentation des matériaux de construction, c'est-à-dire pour le concassage et le broyage. Par conséquent, le choix rationnel des installations de concassage et de broyage et l’optimisation de leurs régimes de fonctionnement représentent un facteur important d’économies d’énergie. Toutefois, il est de plus …


Symmetric Self-Electro-Optic Effect Device: Optical Set-Reset Latch, A. L. Lentine, Scott Hinton, D.A. B. Miller, J. E. Henry, J. E. Cunningham, L.M. F. Chirovsky Apr 1998

Symmetric Self-Electro-Optic Effect Device: Optical Set-Reset Latch, A. L. Lentine, Scott Hinton, D.A. B. Miller, J. E. Henry, J. E. Cunningham, L.M. F. Chirovsky

H. Scott Hinton

We demonstrate an integrated symmetric self-electro-optic effect device consisting of two quantum well p-i-n diodes electrically connected in series. The device acts as a bistable optical memory element with individual set (S) and reset (R) inputs and complementary outputs (optical S-R latch). The switching point is determined by the ratio of the two inputs, making the device insensitive to optical power supply fluctuations when both power beams are derived from the same source. The device also shows time-sequential gain, in that the state can be set using low-power beams and read out with subsequent high-power beams. The device showed bistability …


Design And Characterization Of A Microchannel Optical Interconnect For Optical Backplanes, Yongsheng Liu, Brian Robertson, David V. Plant, Harvard Scott Hinton, William M. Robertson Jan 1997

Design And Characterization Of A Microchannel Optical Interconnect For Optical Backplanes, Yongsheng Liu, Brian Robertson, David V. Plant, Harvard Scott Hinton, William M. Robertson

H. Scott Hinton

The design, modeling, and experimental characterization of a microchannel-based free-space optical interconnect is described. The microchannel interconnect was used to implement a representative portion of an optical backplane that was based on field-effect transistor, self-electro-optic device smart-pixel transceivers. Telecentric relays were used to form the optical interconnect, and two modes based on two different optical window clusterings were implemented. The optical system design, including the optical geometry for different degrees of clustering of windows supported by a lenslet relay and the image mapping associated with a free-space optical system, is described. A comparison of the optical beam properties at the …