ADVANCES IN COMPUTER SCIENCE AND ENGINEERING free download

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Edited by Matt hias Schmidt

Contents

Part 1

Applied Computing Techniques 1
Next Generation Self-learning Style
in Pervasive Computing Environments 3
Kaoru Ota, Mianxiong Dong,
Long Zheng, Jun Ma, Li Li,
Daqiang Zhang and Minyi Guo
Automatic Generation of Programs 17
Ondřej Popelka and Jiří Štastný
Application of Computer Algebra into
the Analysis of a Malaria Model using MAPLE™ 37
Davinson Castaño Cano
Understanding Virtual Reality Technology:
Advances and Applications 53
Moses Okechukwu Onyesolu and Felista Udoka Eze
Real-Time Cross-Layer Routing
Protocol for Ad Hoc Wireless Sensor Networks 71
Khaled Daabaj and Shubat Ahmeda
Innovations in Mechanical Engineering 95
Experimental Implementation
of Lyapunov based MRAC for Small
Biped Robot Mimicking Human Gait 97
Pavan K. Vempaty, Ka C. Cheok, and Robert N. K. Loh
Performance Assessment of Multi-State
Systems with Critical Failure Modes:
Application to the Flotation Metallic Arsenic Circuit 113
Seraphin C. Abou

Object Oriented Modeling
of Rotating Electrical Machines 135
Christian Kral and Anton Haumer
Mathematical Modelling
and Simulation of Pneumatic Systems 161
Djordje Dihovicni and Miroslav Medenica
Longitudinal Vibration of Isotropic Solid Rods:
From Classical to Modern Theories 187
Michael Shatalov, Julian Marais,
Igor Fedotov and Michel Djouosseu Tenkam
A Multiphysics Analysis of Aluminum Welding
Flux Composition Optimization Methods 215
Joseph I. Achebo
Estimation of Space Air Change Rates and CO2
Generation Rates for Mechanically-Ventilated Buildings 237
Xiaoshu Lu, Tao Lu and Martti Viljanen
Decontamination of Solid and Powder
Foodstuffs using DIC Technology 261
Tamara Allaf, Colette Besombes,
Ismail Mih, Laurent Lefevre and Karim Allaf

Dynamic Analysis of a DC-DC Multiplier Converter 285
J. C. Mayo-Maldonado, R. Salas-Cabrera, J. C. Rosas-Caro,
H. Cisneros-Villegas, M. Gomez-Garcia, E. N.Salas-Cabrera,
R. Castillo-Gutierrez and O. Ruiz-Martinez
Computation Time Efficient Models
of DC-to-DC Converters for Multi-Domain Simulations 299
Johannes V. Gragger
How to Prove Period-Doubling Bifurcations
Existence for Systems of any Dimension -
Applications in Electronics and Thermal Field 311
Céline Gauthier-Quémard
Advances in Applied Modeling 335
Geometry-Induced Transport Properties
of Two Dimensional Networks 337
Zbigniew Domański

New Approach to a Tourist Navigation System
that Promotes Interaction with Environment 353
Yoshio Nakatani, Ken Tanaka and Kanako Ichikawa
Logistic Operating Curves in Theory and Practice 371
Peter Nyhuis and Matthias Schmidt
Lütkenhöner’s „Intensity Dependence
of Auditory Responses“: An Instructional Example
in How Not To Do Computational Neurobiology 391
Lance Nizami
A Warning to the Human-Factors Engineer: False Derivations
of Riesz’s Weber Fraction, Piéron’s Law, and Others
Within Norwich et al.’s Entropy Theory of Perception 407
Lance Nizami
A Model of Adding Relations in Two Levels of a Linking
Pin Organization Structure with Two Subordinates 425
Kiyoshi Sawada
The Multi-Objective Refactoring Set Selection
Problem - A Solution Representation Analysis 441
Camelia Chisăliţă-Creţu

fundamentals of electricity free download

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fundamentals of electricity

A review of basic principles of electricity & physics lec (4)

Complex Representation of Signals

Most generally, we can use complex or imaginary values for s (and/or A for that matter)
in equation 9, where s is known as the “complex frequency.” In electrical engineering it
is common practice to use the convention that
j = (-1)^.5 in order to avoid confusion with
the use of i to represent current; we will use that convention for the remainder of this

section. When s is purely imaginary, with the value s = jω and A is real, we can take
advantage of Euler’s relation, that:

We can apply a sinusoidally varying voltage at the frequency ω, V= cos(ωt), across the
capacitor. Note that the V is the real part of Aejωt = Re(Aest).
Substituting into equation 8:

We are interested only the real part of the current, of course, so equation 11 simplifies to
iC = –ωCAsin(ωt), the result of equation 6 above. Looking again at equation 9, when
s = jω the ratio of the voltage to the current is 1/ jω C.
Generalization of Ohm’s law
The ratio of a complex voltage, V, to a complex current, I, is represented by the
impedance, Z. Because sinusoidally varying signals are conveniently represented by
complex numbers (and, as we will see when we discuss the Fourier transform in a
separate section, this can be a generalized representation of most any signal we
encounter), this is an exceptionally powerful formalization. For complex signals, Ohm’s
law states simply that:

The magnitude of the impedance is given in units of Ohms, like resistance, but in
general also incorporates a phase shift. For capacitors, as noted above, the impedance is
1/jωC. Applying Voltage as a cosine wave results in a current that is an inverted sine
wave – a 90° phase shift. In general, multiplication by j represents a 90° phase shift.
As we noted above, the voltage and current relationships for most electrical circuits
(specifically, linear electrical circuits), can be found through the application of Ohm’s
law coupled with KVL and KCL. The Laplace transform solution, as in equation 9, allows
this to be generalized readily to the analysis of devices like capacitors, which store
energy.
One should be a little bit careful here concerning the values of ω, which are in units of
radians/second or angular frequency. In common use we generally speak of frequencies
in cycles/second or “Hertz”. As one cycle is 2π radians, ω=2πf, where the letter f denotes
the frequency in cycles/second. When the input voltage is a sinusoid with frequency, f,
equation 9 may be written as: