bluuebunny/crossref_metadata_2025 huggingface dataset:
A fuzzy logic controlled power electronic system for maximum power point detection of a solar energy panel
Authors: İskender İres
Published: January 2007

Purpose

To analyze the operating performance of a fuzzy logic control (FLC) based solar energy conversion modular system controlled by a digital signal processor (DSP) microcontroller.

Design/methodology/approach

A range of published works relevant to the solar energy conversion modular systems are evaluated and their limitations are indicated in the first section of the paper. The circuit diagram of the panel‐boost converter system is described in the second section. In the third section, a neural network model is suggested for the photovoltaic panel and the model is created in the MATLAB/SIMULINK and then combined with other blocks existing in the system. The design of the FLC method is described in section 4. The simulation and experimental results corresponding to the control of the duty‐cycle of the converter to set the operating point of the solar panel at the maximum power point (MPP) are given in sections 5 and 6, respectively. Section 7, summarizes the results and conclusions of the study.

Findings

The paper suggests a simple dc‐dc boost converter controlled by FLC method. The proposed converter model can be used to obtain maximum power from a photovoltaic panel.

Research limitations/implications

In preparing this paper, the resources books existing in the library of our university and the resources relative to the solar energy conversion and FLC published in English language and reachable through the internet were researched.

Practical implications

The paper suggests a neural network model for a solar panel, which can be used in the simulation of the solar energy panel‐boost converter system. The solar energy panel‐boost converter system proposed in this study can be used by the researchers who are working in the solar energy conversion area.

Originality/value

The suggestion of a neural network model for a solar panel and creation of this model in the MATLAB/SIMULINK environment provides researchers to simulate and to analyze the performance of the solar energy panel‐boost converter system using the MATLAB/SIMULINK simulation program. In addition, since the control approach proposed in this paper does not require the information on temperature and solar irradiance that affect the maximum output power, can effectively find the MPP of the solar panel.
Full‐vectorial finite element solution to open waveguide problems using adaptive perfectly matched layers
Authors: Al Salameh M.S. , Makki S.M.
Published: January 2007

Purpose

To provide an efficient numerical eigenvalue solution for open waveguides with lossy anisotropic materials.

Design/methodology/approach

Vector edge elements are used to represent the core of the problem, and an adaptive perfectly matched layer (PML) is used to truncate the surrounding region. The parameters of the PML are allowed to change at each frequency to obtain accurate results using small number of unknowns.

Findings

The method is able to solve many configurations, and considerable reduction in mesh size has been reported. In addition, by adapting the solution according to some error criterion, it will be possible to minimize the dependence on human experience and rely more on automated algorithms.

Research limitations/implications

There is a need to improve the performance of the adaptive algorithm by building an automatic adaptive procedure that can work without human intervention.

Practical implications

A systematic full‐wave algorithm for solving practical electromagnetic engineering problems associated with open waveguides, such as planar transmission lines and optical waveguides, using relatively small computer resources.

Originality/value

Proposed a new “dimension” of adaptation for PML, besides the classical h‐/p‐/hp adaptation methods available in literature. Thus, the requirement for smaller computer resources makes this method cost‐effective for industry in the design of practical open waveguides.
Efficient transient simulation of interconnect networks
Authors: Condon M. , Dautbegovic E. , Brennan C.
Published: January 2007

Purpose

To provide an efficient and accurate model for interconnect networks characterised by frequency‐domain scattering or admittance parameters. The parameters are derived from measurements or rigorous full‐wave simulation.

Design/methodology/approach

Initially, Hilbert transform relationships are enforced to ensure causality. A reverse Fourier series representation of the discrete data is then converted to the z‐domain and from this a state‐space formulation is determined. This enables the application of a judiciously chosen model reduction algorithm to obtain an efficient time‐domain representation of the network.

Findings

Sample results from both simulated and measured data indicate the efficacy of the proposed modelling strategy. For successful implementation of the strategy, it is necessary to employ the Hilbert transform to ensure that a causal impulse response is obtained.

Practical implications

The method is applicable to the interconnect networks for which the analytical models cannot be obtained due to the complexity and inhomogeneity of the geometries involved.

Originality/value

The work combines in a novel manner aspects from several existing techniques proposed for network simulation and model reduction. The end result is a highly efficient causal, stable and passive representation of the network in question for implementation in a time‐domain circuit simulator.
Optimizing a transformer driven active magnetic shield in induction heating
Authors: Sergeant Peter , Dupré Luc , Melkebeek Jan
Published: January 2007

Purpose

To design an optimal active shield for the mitigation of the magnetic stray field around an induction heating device.

Design/methodology/approach

The active shield consists of several compensation coils in series and generates a counter field opposite to the main field. One extra compensation winding – the “generating compensation winding” (GCW) – is positioned close to the excitation coil and works as the secondary winding of a transformer. The power in this winding is used to drive the other compensation coils (the active shield), which are the load of the transformer. A circuit with passive components is inserted between the GCW and the other compensation coils. The shield is optimal if it achieves a high field reduction, while the energy dissipation is low. By using a genetic algorithm (GA) that minimizes an objective function, the optimization algorithm finds the optimal geometry and the optimal current for the GCW and the other compensation coils. The objective function uses time harmonic and axisymmetric finite element calculations.

Findings

The transformer driven active shield reduces the magnetic field effectively. It is cheap and easy to build, but it works well only for one frequency.

Research limitations/implications

The shield is sensitive to tuning of the passive circuit and to changes in the frequency of the induction heater.

Practical implications

This transformer driven shield is an alternative for the classical active shield with external power supply.

Originality/value

An active shield that does not need an external power supply is a cheap solution for the shielding of magnetic fields.
Post processing for the vector finite element method: from edge to nodal values
Authors: Vollaire Christian , Musy François , Perrussel Ronan
Published: January 2007

Purpose

Propose post processing methods for the edge finite element (FE) method on a tetrahedral mesh. They make it possible to deduce vector values on the vertices from scalar values defined on the edges of the tetrahedra.

Design/methodology/approach

The new proposed techniques are based on a least squares formulation leading to a sparse matrix system to be solved. They are compared in terms of accuracy and CPU time on a FEs formulation for open boundary – frequency domain problems.

Findings

A significant improvement of vector values accuracy on the vertices of the tetrahedra is obtained compared to a classical approach with a very small additional computation time.

Originality/value

This work presents techniques: to obtain the values at the initial nodes of the mesh and not inside the tetrahedra; and to take into account the discontinuity to the interface between two media of different electromagnetic properties.
Algorithms for automatic torus motor parameters identification: comparative study
Authors: Al‐Badi Abdullah , Gastli Adel , Jervase Joseph A.
Published: January 2007

Purpose

The parameters of axial‐field machines are very small compared with the parameters of conventional machines. Different measuring methods are normally used in order to obtain good estimates of the machine parameters. These methods are difficult to perform, costly and time consuming. This paper proposes the use of genetic algorithms to predict the self and mutual inductances of a specific type of axial‐field machine, the Torus motor.

Design/methodology/approach

The parameter extraction is reformulated as a search and optimization problem in which the only requirement is a set of values of current versus time and an approximate estimate of the parameters.

Findings

The predicted machine self and mutual inductances are verified by comparing with several measuring methods and excellent agreement is obtained.

Originality/value

Demonstrates that genetic algorithms can predict the self and mutual inductances of the Torus machine automatically with high accuracy.
A combined multicell‐WENO solver for the Boltzmann‐Poisson system of 1D semiconductor devices
Authors: Domaingo A. , Galler M. , Schürrer F.
Published: January 2007

Purpose

To present a new direct solution method for the Boltzmann‐Poisson system for simulating one‐dimensional semiconductor devices.

Design/methodology/approach

A combination of finite difference and finite element methods is applied to deal with the differential operators in the Boltzmann transport equation. By taking advantage of a piecewise polynomial approximation of the electron distribution function, the collision operator can be treated without further simplifications. The finite difference method is formulated as a third order WENO approach for non‐uniform grids.

Findings

Comparisons with other methods for a well‐investigated test case reveal that the new method allows faster simulations of devices without losing physical information. It is shown that the presented model provides a better convergence behaviour with respect to the applied grid size than the Minmod scheme of the same order.

Research limitations/implications

The presented direct solution methods provide an easily extensible base for other simulations in 1D or 2D. By modifying the boundary conditions, the simulation of metal‐semiconductor junctions becomes possible. By applying a dimension by dimension approximation models for two‐dimensional devices can be obtained.

Practical implications

The new model is an efficient tool to acquire transport coefficients or current‐voltage characteristics of 1D semiconductor devices due to short computation times.

Originality/value

New grounds have been broken by directly solving the Boltzmann equation based on a combination of finite difference and finite elements methods. This approach allows us to equip the model with the advantages of both methods. The finite element method assures macroscopic balance equations, while the WENO approximation is well‐suited to deal with steep gradients due to the doping profiles. Consequently, the presented model is a good choice for the fast and accurate simulation of one‐dimensional semiconductor devices.
A new methodology for distribution systems faults identification, location and characterization
Authors: Campoccia A. , Di Silvestre M.L. , Incontrera I. , Riva Sanseverino E.
Published: January 2007

Purpose

Identify a new methodology for fault characterization, identification and location in electrical distribution systems, based on the use of matrix algebra.

Design/methodology/approach

The developed diagnostic methodology is based on a high precision analytical model of the network using a distributed parameters representation.

Findings

Test results have proved the approach to be efficient and precise, while providing a generalized quadripolar model of a line affected by the most common kinds of fault.

Research limitations/implications

Generalization to a greater number of fault cases, experimental tests.

Practical implications

Utilities are quite interested in such items, since the new required quality standards put severe constraints on faults management and clearance. On the other hand, the system requires a rather complete measurement equipment of secondary substations.

Originality/value

The paper presents a new diagnostic technique for faults identification, location and characterization in distribution systems.
Application of different saturation curves in a mathematical model of hysteresis
Authors: Włodarski Zdzisław , Włodarska Jadwiga , Brykalski Andrzej
Published: January 2007

Purpose

The increase of the accuracy of a mathematical model of hysteresis by the choice of the optimum saturation curve for a given material.

Design/methodology/approach

Hysteresis loops of typical soft magnetic materials are approximated with the help of the Taka´cs magnetization model using different saturation curves. The quality of approximations is determined by the deviation of computed magnetic induction amplitudes, iron losses, apparent remanences and coercivities from the measured values.

Findings

By the proper choice of saturation curve, the relative inaccuracy of approximations can be reduced with reference to the original model based on tangent hyperbolic function.

Research limitations/implications

The accuracy of approximations worsens close to saturation because of the excessive rise of magnetization due to the linear term of the model. This effect should be minimized by the application of complex saturation curves using greater number of parameters.

Practical implications

Owing to the convenient analytical form and increased accuracy, the model equations can be used in simpler practical evaluations of hysteresis effects and for teaching purposes.

Originality/value

Presented form of model equations enables approximation of hysteresis loops and the evaluation of main characteristics of magnetic materials on the basis of any saturation curve.
Wave reflection on unconventional mirrors
Authors: Hillion P.
Published: January 2007

Purpose

To extend to electromagnetism the acoustic wave reflections on time reversal mirrors used in medical imaging, nondestructive testing and underwater acoustics.

Design/methodology/approach

Recent works (1993‐2004) analyse the reflection of acoustic waves on time reversal mirror. To perform the same job in electromagnetism, the behaviour of the electromagnetic field tensor under the space and time inversions of the referential is investigated and also, when in addition an exchange of two coordinates exists. All these reflections are supposed obtained from perfect but unconventional mirrors.

Findings

Electromagnetic reflections on unconventional mirrors have remarquable features since some of them give birth to a real twin source of the incident source with an opposite polarization.

Practical implications

The techniques used in acoustic to manufacture time reversal mirrors can be used in electromagnetism with possible applications of such mirrors for instance in cameras to avoid reversed photographs but no information on practical realizations has appeared in the open literature.

Orginality/value

Extends research on electromagnetism.
Tracing AM‐detector transfer characteristics
Authors: Tadeusiewicz M. , Hałgas S.
Published: January 2007

Purpose

Showing both theoretically and experimentally that the Newton‐Raphson algorithm is a very efficient tool for computing the transfer factor characteristic of AM detectors.

Design/methodology/approach

An equation which describes the diode and transistor AM detectors has been investigated. Using elementary techniques of mathematical analysis, some theoretical properties of the equation have been formulated and convergence of the Newton‐Raphson algorithm has been proved.

Findings

It is shown that the Newton‐Raphson algorithm is an efficient tool for tracing the transfer factor characteristics of both diode and transistor AM detector. The convergence of this algorithm is proved and a comparison with SPICE simulation is made. Furthermore, the diode and transistor AM detectors have been built up and validating measurements have been carried out. The comparison shows that the algorithm proposed in the paper computes the characteristics fast achieving good accuracy.

Research limitations/implications

The results obtained are limited to those described in the paper diode and transistor AM detectors.

Originality/value

Some properties of the nonlinear equation describing the AM detectors are formulated and convergence of the Newton‐Raphson algorithm to a unique solution is proved.
A discrete‐time model including cross‐saturation for surface permanent‐magnet synchronous machines
Authors: De Belie Frederik M.L.L. , Melkebeek Jan A.A. , Vandevelde Lieven , Geldhof Kristof R. , Boel René K.
Published: January 2007

Purpose

To provide a discrete‐time nonlinear model for surface permanent‐magnet synchronous machines (SPMSMs) in order to discuss the stability of such machines.

Design/methodology/approach

Through differencing the co‐energy, obtained from a finite element method, the main flux path can be described by a complex reluctance. Furthermore, for a SPMSM, an equivalent circuit is presented that includes the eddy‐current losses and the voltage drops across stator resistance and leakage inductance. The model is transformed to a discrete‐time state‐space model by using a forward rectangular rule. By using a root locus technique, the stability of the new model is discussed.

Findings

From the calculated root locus it is concluded that the stability of a SPMSM is only guaranteed for certain values of the open loop gain. Moreover, by using the forward rectangular rule, it is concluded that a well‐considered time step has to be chosen.

Research limitations/implications

The model considers the fundamental space harmonic components only. Moreover, the saturation of the leakage flux path is neglected.

Practical implications

As the model is formulated in discrete time, it can be used in modern drives where a digital controller is used.

Originality/value

This paper presents an equivalent electrical circuit for SPMSMs that takes into account the saturation of the magnetizing flux paths as well as the magnetic interaction between the two orthogonal magnetic axes.
Frequency and time domain homogenization of laminated magnetic cores and windings in FE models of high‐frequency electromagnetic devices
Authors: Gyselinck J. , López‐Fernández X.M.
Published: January 2007

Purpose

To review and discuss recently proposed homogenization methods for laminated magnetic cores and multi‐turn windings in FE models of electromagnetic devices.

Design/methodology/approach

The frequency‐domain homogenization is based on the adoption of complex and frequency‐dependent material characteristics (e.g. reluctivity) in the homogenized domain. The value of the complex quantity is obtained analytically or by means of a simple 2D FE model. The time‐domain counterpart requires the introduction of additional unknowns and equation.

Findings

The homogenization methods allow to take into account the global eddy current effect in the individual laminations and wires, with a reasonable precision and computational cost.

Research limitations/implications

The homogenization methods have been validated numerically, i.e. by comparison with brute‐force FE computations where the eddy current effects are directly and accurately taken into account. Experimental validation should follow.

Originality/value

The analogy between the homogenization of laminated cores and windings has been evidenced.
Comparison of artificial immune systems and genetic algorithms in electrical engineering optimization
Authors: Freschi Fabio , Repetto Maurizio
Published: January 2007

Purpose

The purpose of this study is to investigate and compare the ability of a new optimization technique based on the emulation of the immune system to detect the global maximum with multimodal functions and to test the capability of exploring the parameter space with respect to clustering enhanced Genetic Algorithms (GA).

Design/methodology/approach

Both algorithms have been tested on analytical test functions and on numerical functions of applicative interest. A set of performance criteria has been defined in order to numerically compare the performances of both optimization strategies.

Findings

Results show the great ability of Artificial Immune Systems (AIS) in thoroughly exploring the space of variables. On the other side, GA are faster to converge to the global optimum, but selection pressure can reduce the number of detected local optima.

Originality/value

This work is an attempt to assess the performances of a relatively new optimization algorithm based on AIS and to find its behavior on multimodal test functions, using GAs as reference optimization technique.
Hybrid GA neuro‐fuzzy damping control system for UPFC
Authors: Khan Laiq , Lo K.L. , Jovanovic S.
Published: January 2007

Purpose

The aim of the paper is to develop a novel genetic algorithm (GA)‐based supplementary NeuroFuzzy damping control system for the unified power flow controller (UPFC).

Design/methodology/approach

The designed scheme employs a micro‐GA (μ‐GA) to avoid being trapped in a local minimum as opposed to the use of the classical back‐propagation technique. The scheme also uses the “Grand‐Parenting” technique for seeding the initial population to hasten the GA convergence speed. To further speed up the GA for solving the optimization problem, a parallelμ‐GA scheme is also used.

Findings

It has been discovered that a parallelμ‐GA scheme with three computers setup is approximately three times faster than theμ‐GA with a single computer node. Also whenμ‐GA is integrated with the “Grand‐Parenting” technique for seeding the initial population, it would hasten the convergence speed. The control scheme exhibits strong robustness and excellent damping performance when tested on a multi‐machine power system.

Originality/value

Presentation of a novel NeuroFuzzy‐based UPFC that exhibits strong robustness and excellent damping performance.
A new computational approach for optimal reconfiguration of radial distribution systems using a fuzzy controlled genetic algorithm
Authors: Prasad K. , Sahoo N.C. , Ranjan R. , Chaturvedi A.
Published: January 2007

Purpose

This research paper reports a novel genetic algorithm (GA)‐based approach for reconfiguration of radial distribution networks for real loss minimization and power quality improvement.

Design/methodology/approach

A fuzzy controlled GA has been used for efficient reconfiguration of radial distribution systems for loss minimization and power quality improvement. The special features of the proposed algorithm are: an improved chromosome coding/decoding for network representation so as to preserve the radial property without islanding any load after reconfiguration and an efficient convergence characteristics attributed to fuzzy controlled mutation.

Findings

The proposed network reconfiguration algorithm is very much effective in arriving at the global optimal solution (minimum loss network structure) because of efficient search of the solution space. Also, no invalid chromosomes are generated in the genetic evolution because of appropriate coding/decoding. The algorithm is found to be very much suitable for real time implementations.

Research limitations/implications

This research paper provides the power distribution engineers with a computationally efficient approach for optimal operation of distribution systems.

Practical implications

The algorithm proposed in this paper is computationally much faster compared to most of the present day mathematical programming approaches for distribution system operation. This makes it very much attractive for online implementations in any radial distribution network.

Originality/value

This paper has proposed a novel chromosome coding/decoding technique for radial distribution system and a fuzzy logic‐based mutation probability controller for efficient search of global solution space to be used in GA‐based optimal operation of radial distribution systems.
Novel efficient methods for inductance calculation of meander inductor
Authors: Stojanović Goran , Živanov Ljiljana , Damnjanović Mirjana
Published: January 2007

Purpose

Present 3D electromagnetic simulators have high accuracy but they are time and memory expensive. Owing to a fast and simple expression for inductance is also necessary for initial inductor design. In this paper, new efficient methods for total inductance calculation of meander inductor, are given. By using an algorithm, it is possible to predict correctly all inductance variations introduced by varying geometry parameters such as number of turns, width of conductor or spacing between conductors.

Design/methodology/approach

The starting point for the derivation of the recurrent formula is Greenhouse theory. Greenhouse decomposed inductor into its constituent segments. Meander inductor is divided into straight conductive segments. Then the total inductance of the meander inductor is a sum of self‐inductances of all segments and the negative and positive mutual inductances between all combinations of straight segments. The monomial equation for the total inductance of meander inductor has been obtained by fitting procedure. The fitting technique, using the method of least squares, finds the parameters of the monomial equation that minimize the sum of squares of the error between the accurate data and fitted equation. The paper presents new expression for inductance of meander inductor, in the monomial form, which is suitable for optimization via geometric programming. The computed inductances are compared with measured data from the literature.

Findings

The first, recurrent, expression has the advantage that it indicates to the designer how the relative contributions of self, positive, and negative mutual inductance are related to the geometrical parameters. The second expression presents the inductance of the meander inductor in the monomial form, so that the optimization of the inductor can be done by procedure of the geometric programming. Simplicity and relatively good accuracy are the advantages of this expression, but on the other hand the physical sense of the expression is being lost. Thus, the effects of various geometry parameters on inductance are analyzed using two expressions and the software tool INDCAL.

Practical implications

Applied flexible efficient methods for inductance calculation of meander inductor are able to significantly increase the speed of RF and sensor integrated circuit design.

Originality/value

For the first time a simple expression for fast inductance calculation for meander inductor in monomial form is presented. It is explained how such an expression is generated, which can be directly implemented in circuit simulators.
The multi‐mode chaotic behaviors: N+N and 2D N‐scroll chaotic attractors
Authors: Türk Mustafa , Ata Fikret
Published: January 2007

Purpose

The purpose of this paper is to present a simulation and realization of the different types of chaotic attractors using the generalized Chua's circuit equations.

Design/methodology/approach

This paper presents n+n‐scroll and 2D n‐scroll chaotic attractors by introducing multiple breakpoints to the nonlinearity. Two piece‐wise linear elements controlled with x‐ and y‐state space variables are used. Chaotic scrolls are originated through both x‐ and y‐axes. The current feedback operational amplifiers are preferred in the experimental circuits because of their wide bandwidth.

Findings

It is possible to increase the number of the scrolls in two directions by varying the number of breakpoints in the piece‐wise linear characteristics or changing the location of equilibrium points of the system on 2D‐plane. Theoretically developed behaviors are also experimentally tested.

Originality/value

The excellent adaptation is observed between theoretical and experimental results. This paper also provides useful information about how to build the multiple breakpoints nonlinear elements using the simulation results.
Sliding‐mode control for speed sensorless induction machine drive using an adaptive nonlinear rotor flux observer
Authors: Arab Markadeh G.R. , Soltani J.
Published: January 2007

Purpose

To propose and adaptive nonlinear controller for adjustable speed sensorless induction motor drive, using a novel adaptive rotor flux observer. The adaptive flux observer scheme in this paper provides the simultaneous estimation of the rotor speed, rotor resistance and stator resistance.

Design/methodology/approach

The IM rotor speed and rotor flux controllers are designed based on combination of input‐output feedback linearizing, linear optimal feedback control and sliding‐mode (SM) control methods. In addition a novel adaptive rotor flux observer is designed based on Lyapunov theory. The proposed control method is tested by simulation and experimental results.

Findings

The composite rotor speed and rotor flux observer in combination with adaptive rotor flux scheme guarantees a perfect speed, torque and flux tracking control for the IM sensorless drive.

Research limitations/implications

The proposed control method has a drawback in the IM low speed operating region. Additional research may be able to solve this problem as well as should analyze the sensitivity of the IM drive system performance with respect to variation of the system controller and adaptive flux observer gains. In addition, this research should also analyze the influence of sampling rate, truncation errors, measurement noise, simplifying model assumption and magnetic saturation.

Practical implications

The proposed control method can be used for adaptive and robust control of the IM drive where an optimal efficiency is desired subject to the variable load torque demand.

Originality/value

Based on Lyapunov theory, a novel adaptive rotor flux observer is introduced in which the rotor speed, rotor resistance and stator resistance are treated as the unknown constant parameters.
Detection of acceptability regions by means of an interval arithmetic‐based algorithm
Authors: Spagnuolo G.
Published: January 2007

Purpose

To introduce an interval arithmetic (IA)‐based approach to tolerance analysis and design and to yield evaluation. The technique distinguishes itself by its reliability in the detection of even non convex and/or non simply connected regions of acceptability.

Design/methodology/approach

Range methods, and IA among them, inherently allow the evaluation of an overestimation of the true range spanned by a performance function of a given system because of variation of its parameters values. Such a feature is of great help in performing the robust design of any system, that is, in doing the placement of the design set within the region of acceptability, even in the presence of tolerances and parameters values drifts.

Findings

The IA‐based branch and bound numerical procedure proposed in the paper has shown its reliability and robustness during the tolerance analysis of systems exhibiting quite involved regions of acceptability.

Research limitations/implications

Many remarks are reported in the paper to complete the research and extend it to a larger class of problems.

Practical implications

The procedure might be built into simulation environments in order to help the designer in dominating tolerances effects.

Originality/value

This paper shares in suggesting the use of a powerful tool, i.e. range methods, in the area of tolerance design and reliability.
Electromagnetic plane wave scattering from building surfaces
Authors: Delfino F. , Girdinio P. , Minervini L. , Nervi M.
Published: January 2007

Purpose

To provide a detailed investigation about methods commonly used for the computation of high‐frequency electromagnetic fields in the vicinity of obstacles that can reflect or diffract them. This is useful to create an elementary block that can be used to evaluate with a high accuracy the propagation of high‐frequency electromagnetic waves in real urban environment.

Design/methodology/approach

The approach is based on a realistic application of the asymptotic theory of the uniform theory of diffraction. Therefore, the effect of material roughness and its electromagnetic properties on the reflection are taken into account.

Findings

Provides information about the mechanisms involved in electromagnetic field propagation in urban environment, and the relative importance of each one.

Research limitations/implications

In urban environment the buildings obviously have finite dimensions. The diffraction equations examined in the paper are strictly valid only in the case of infinite wedges; therefore, the behaviour of real building edges has not been taken rigorously into account.

Practical implications

A source of information for researchers interested in the development of a simulator for the electromagnetic propagation in urban environment.

Originality/value

This paper is aimed at providing to researchers, in a more comprehensive way, all information needed for the study of electromagnetic propagation in an environment containing many close scatterers.
Evaluation of UPFC and ASVC applied to nonlinear load model
Authors: Qader M.R.
Published: January 2007

Purpose

Unified power flow controller (UPFC) and advanced static VAR compensator (ASVC) devices are now recognized as the most important flexible AC transmission systems (FACTS) devices. This paper aims to focus on this.

Design/methodology/approach

The effects of the location of such installation FACTS devices are examined.

Findings

The UPFC as a voltage regulator and ASVC devices applied to a non‐linear load are modeled and analyzed. It was found that the optimum installation position for a UPFC device is at the sending end bus where wide range of receiver terminal line voltage and active power can be controlled. However, it was also found that the optimum installation position for an ASVC device is at the receiving end bus where a wide range of receiver terminal line voltage and active power can be controlled. In both cases, it was found that a wider range of reactive power could be controlled when the devices are installed closer to the receiving end bus.

Originality/value

Shows that the mid‐point of a transmission line is the optimal location for some FACTS devices or reactive power support. The proof is based on a fixed receiving end voltage magnitude, which is practically not valid.
A comparison of numerical solutions of fourth‐order boundary value problems
Authors: Inc M. , Cherruault Y.
Published: January 2007

Purpose

To use the modified decomposition method to obtain numerical solutions of fourth‐order boundary value problems.

Design/methodology/approach

The modified form of Adomian decomposition method (ADM) originated by Wazwaz in 1997/1998 is considered and applied. In addition, a comparison of the modified decomposition method and the perturbed collocation method when applied to the solutions of fourth‐order boundary value problems is presented.

Findings

The comparison of these two methods has shown that the modified or standard decomposition methods are reliable, efficient and easy to use for solving higher‐order boundary value problems.

Research limitations/implications

This study provides both an analysis of the method as well as a comparison of the numerical solutions of fourth‐order boundary value problems. Future research in the application of this methodology to other areas should prove productive.

Practical implications

The numerical results, using the modified technique, were obtained from selected fourth‐order boundary value problems which were linear and non‐linear problems.

Originality/value

Assesses, by comparison, methods for the numerical solutions of fourth‐order boundary value problems. Shows through original numerical results the value of the modified or standard decomposition methods in the solution of these problems.
The Alienor method coupled to the Brent algorithm
Authors: Ziadi Abdelkader , Khelladi Samia , Cherruault Yves
Published: January 2007

Purpose

Classical multidimensional global optimization methods are difficult to implement in high dimensions. To show that the Alienor method coupled with the Brent algorithm can avoid this difficulty.

Design/methodology/approach

Use is made of the Alienor method and the Brent algorithm to obtain algorithms that were applied to test functions having several local minima.

Findings

Interesting results concerning the number of evaluation points were obtained. It was shown that this coupling can be improved if α‐dense curves of minimal length were used.

Research limitations/implications

Multidimensional global optimization problems have proven to be difficult to implement in high dimensions. This research continues the search for improved methods by coupling existing established methods such as Alienor with others such as the Brent algorithm.

Originality/value

A new coupled method has been developed and algorithms obtained to tackle such global optimization problems. The coupling is unique and the algorithms are tested numerically on selected functions.
Solving constrained global optimization problems without penalty parameters
Authors: Konfe Balira O. , Cherruault Yves , Some Blaise
Published: January 2007

Purpose

To propose a new method for solving constrained global optimization problems using a method that consists of transforming a constrained global optimization problem into an unconstrained one without using any penalty coefficients.

Design/methodology/approach

Use of an unconstrained global optimization method such as the Alienor method which has been adapted for several variables.

Findings

Use of the adapted Alienor method allowed the solution of the transformed problem with little difficulty.

Research limitations/implications

Transforms the original objective function into a new one involves the introduction of some extra parameters. Cannot guarantee the convergence to a global solution of the original problem. The simple described approach, provides new possibilities.

Practical implications

No further parameters introduced in this new approach, and no conditions or hypotheses are imposed on the objective function or on the constraints.

Originality/value

New method of transforming a constrained problem into an unconstrained one, with use of proven Alienor method adapted to several variables.
Pharmacokinetic parameters identification using the combined Alienor/Adomian methods
Authors: Zaidi Z. , Bezzina M. , Cherruault Y.
Published: January 2007

Purpose

A two‐compartmental open model to study metabolism/elimination that arise in clinical observation and pharmacokinetics, is presented. The purpose of this work is to show how it is possible to combine the two methods of Alienor and Adomian with observability identification and controllability principles to optimize drug doses.

Design/methodology/approach

Cliniciansa try to know how to detect patients at high risk of 5‐Fu (intravnous administration). The approach is to use a two‐compartmental open model to study its metabolism/elimination and assume that it has a nonlinear behaviour. The methodology chosen brings together two proven techniques to solve the arising differential system. A case study “5‐Fu pharmacokinetics” provides an illustrative application of the combined methods.

Findings

On the basis of the numerical results obtained in the case study it was found that a chart could be set up for individual dose adjustment according to individual parameters relating to dose and plasma concentration. The use of mathematical modeling in this field was shown to be justified.

Research limitations/implications

This research is especially important in the pharmaceutical industry since it allows the prediction of drug behaviour in the body. In future work, we will consider the controllability of this problem.

Practical implications

Improved mathematical modelling would allow physicians to treat patients in an optimal way without compromising their comfort or safety. The practitioner would need only to follow a specified procedure.

Originality/value

The new procedure will be especially important to the pharmaceutical industry and this methodology, combined with statistical analysis, will help to improve drug benefits.
New results about the identifiability of linear open bicompartmental homogeneous system and the identification of open Michaelis‐Menten system by a linear approach
Authors: Hebri B. , Cherruault Y.
Published: January 2007

Purpose

To prove two results. Namely that if in a linear homogeneous bicompartmental system one compartment is measured then it is indefinable. The second one is related to the identification of non‐linear compartmental models by mean of a linear method.

Design/methodology/approach

The first result is generalized to linear non‐homogeneous bicompartmental systems of Michaelis‐Menten (M‐M systems). The second one is related to the identification of a non‐linear compartmental model. The obtained linear system is not homogeneous and must be generalized to nonhomogeneous systems. Then the Jacobian matrix associated to the M‐M systems is identified and the M‐M parameters are deduced by continuity from the Cauchy problem's solution.

Findings

Both stated results were proved and any open linear bicompartmental system whether homogeneous or not, of the type I is identifiable.

Research limitations/implications

In compartmental analysis the exchange hypothesis allows us to represent a model of any phenomenon depending on time. Many phenomena require “the enzyme reactions” leading to the M‐M laws. These laws assert that the quantity of matter going from compartment can be defined and M‐M constants prescribed. This research considers both homogeneous and nonhomogeneous systems cases.

Practical implications

Contributes to the identification of linear and non‐linear bicompartmental systems which are of biocybernetical significance.

Originality/value

The two proven results are new and applicable.
Combined Adomian/Alienor methods for solving adaptive control problems in chemotherapy
Authors: Zaidi Z. , Twizell E.H. , Cherruault Y. , Meulemans A.
Published: January 2007

Purpose

To show how the combined Adomian/Alienor methods for solving adaptive control problems can successfully be applied to chemotherapy.

Design/methodology/approach

Problem formulation is first developed and combined mathematical methods (Adomian/Alienor) are used for the solution of non‐linear differential equations/systems with unknown parameters and without discretization or linearization. The approach is applied to biological systems and in particular the drug/tumour two compartment model is addressed.

Findings

A general abstract framework for the identification and the control of a non‐linear evolution system has been developed. It was found that it is possible to identify and control a system using a powerful technique based on a combination of the Adomian/Alienor methods. This produced a methodology which showed its superiority over the traditional methods in that as a result of their implementation we can predict and optimize the individual dosage in the described application.

Research limitations/implications

The combined techniques proved to be successful for the optimization of drug administration where account is taken of effectiveness, usefulness and safety. Further research collaboration between multidisciplinary scientists and practitioners directed towards more insight into drug/cancerous cells behaviour is required.

Practical implications

An alternative to other classical techniques to solve control/identification problems has been produced.

Originality/value

New combined technique given which is superior to traditional ones for certain therapeutic cases.
Systems theory and the science of military command and control
Authors: Skyttner Lars
Published: January 2007

Purpose

To propose a new military academic area called the “Science of Military Command and Control” which will demand an entirely new way of thinking regarding decision‐making command and control and use of modern technology.

Design/methodology/approach

Defines basic terms and concepts of the discipline and a meta‐theory consisting of General Systems Theory and its related areas is presented.

Findings

Three main perspectives are recommended where the first is General Systems Theory, the second is the Cybernetics Regulatory Paradigm and the third is Communication and Information Theory. The components of military command and control system were analysed and a general model for information system development recommended.

Research limitations/implications

Current thinking in favour of a “network‐defense” that is based on information and communication technology has changed the traditional perspective. New thinking and research development is required. New research using scientific approach is needed.

Practical implications

Shows that the old and exact strategies for Swedish defence has totally changed. New military academic area is proposed and a general model outlined.

Originality/value

Proposes a new way of thinking which will affect future military planning. A cybernetic/systemic methodology provides solutions.
Systemic philosophy and the philosophy of social science – Part I
Authors: Johannessen Jon‐Arild , Olaisen Johan
Published: January 2007

Purpose

To discuss systemic thinking in relation to the naturalistic and anti‐naturalistic position in the philosophy of social science. To develop the theme in two parts: I and II.

Design/methodology/approach

A cybernetic approach is taken and a discussion on what is the foundation for the philosophy of social science for systemic thinking is developed.

Findings

The findings for Part I are that the rationalistic view of knowledge is based on reflection and reason. The empirical viewpoint on knowledge based on observations. The realistic view of knowledge is based on the link between the rationalistic and the empirical point of view. The systemic viewpoint is based on the realistic view of knowledge.

Practical implications

Provided assistance to social scientists who study social systems from the systemic or cybernetic point of view. Gives researchers studying problems/phenomena in social systems a systemic viewpoint.

Originality/value

It positioned systemic thinking in relation to the philosophy of social science.
Cybernetics and systems on the web: internet newsletters
Authors: Andrew Alex M.
Published: January 2007

Purpose

Attention is drawn to an announcement of two publications relating to the work of Humberto Maturana, and to a new online encyclopedia of systems and cybernetics. The latter uses Wikimedia technology for free interaction, and this is discussed. Advice on combating spyware and other forms of malware is reviewed, as well as surveys of how to make computers quieter in operation, and of the worrying question of when to switch off between periods of use.

Design/methodology/approach

The aim is to review developments on the internet, especially those of general cybernetic interest.

Findings

Some of the developments reported have research value, while others bear on practical aspects of computer use and internet access.

Practical implications

The comments on security may prompt urgent action by readers. Otherwise the implications are for access to information and for computer quietness and economy.

Originality/value

It is hoped this is a valuable periodic review.