bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical simulation of the performance of a human nasal cavity
Authors: Castro Francisco , Parra Teresa , Quispe César , Castro Pilar
Published: August 2011

Purpose

The paper aims to focus on airflow and heat transfer inside the human nasal cavity. The contribution of this work is the inertial analysis of the momentum and thermal stress of the cavity throughout the respiratory cycle.

Design/methodology/approach

By means of computer tomography scans, an accurate three‐dimensional anatomical representation of the human nasal cavity was obtained. A three‐dimensional numerical model is presented in order to predict the time evolution of flow patterns during a quiet breathing cycle, covering inhalation and exhalation. An inertial analysis of the momentum and a detailed study of the thermal behaviour during the breathing cycle is carried out.

Findings

Head loss, velocity and temperature values are in agreement with experimental results from previous studies. Based on these results, the influence of the inhalation and the exhalation on the flow pattern and air conditioning has been reviewed. Results suggest that the anterior and posterior turbinate regions are where the air conditioning is primarily produced.

Practical implications

The future goal is to investigate respiratory disorders to increase the effectiveness of the eventual treatment of the pathology. The model could be a useful tool to predict, for instance, the modification of the flow patterns due to septal perforations.

Originality/value

The transient resolution provides insight into the momentum and thermal inertia though the breathing which is far from being well understood.
Seismic response analysis models of an oil storage tank with a floating roof
Authors: Nagashima Toshio , Tsukuda Takenari , Suemasu Hiroshi , Sogabe Kiyoshi
Published: August 2011

Purpose

The purpose of this paper is to investigate the effects of the finite element models on the response of a free surface or a floating roof, which is important for safety assessment of oil storage tanks.

Design/methodology/approach

Structural analyses of shell structures using the three‐dimensional finite element method (FEM), potential flow analyses by FEM, and fluid‐structure interaction analyses by strong coupling of the structural and fluid analyses were performed. In‐house software was utilized for computations shown in this paper except the solver for non‐symmetric sparse matrix.

Findings

A model with a rigid tank and an elastic roof was confirmed to be able to perform the seismic response analysis most effectively from the viewpoint of computational cost with no reduction in accuracy.

Research limitations/implications

The stress distribution on the floating roof will be evaluated to assess the safety of oil storage tanks subjected to seismic waves in the future research.

Originality/value

This paper shows the dynamic responses of a liquid storage tank subjected to seismic motion using four different analysis models and the results were compared. It was concluded that a model with a rigid tank and an elastic roof can perform the seismic response analysis most effectively from the viewpoint of both accuracy and computational cost.
Dependence of contact area on the resolution of fractal interfaces in elastic and inelastic problems
Authors: Panagouli Olympia , Mistakidis Euripidis
Published: August 2011

Purpose

The purpose of this paper is to investigate the influence of the resolution with which interfaces of fractal geometry are represented, on the contact area and consequently on the contact interfacial stresses. The study is based on a numerical approach. The paper focuses on the differences between the cases of elastic and inelastic materials having as primary parameter the resolution of the interface.

Design/methodology/approach

A multi‐resolution parametric analysis is performed for fractal interfaces dividing a plane structure into two parts. On these interfaces, unilateral contact conditions are assumed to hold. The computer‐generated surfaces adopted here are self‐affine curves, characterized by a precise value of the resolution δ of the fractal set. Different contact simulations are studied by applying a horizontal displacement s on the upper part of the structure. For every value of s, a solution is taken in terms of normal forces and displacements at the interface. The procedure is repeated for different values of the resolution δ. At each scale, a classical Euclidean problem is solved by using finite element models. In the limit of the finest resolution, fractal behaviour is achieved.

Findings

The paper leads to a number of interesting conclusions. In the case of linear elastic analysis, the contact area and, consequently, the contact interfacial stresses depend strongly on the resolution of the fractal interface. Contrary, in the case of inelastic analysis, this dependence is verified only for the lower resolution values. As the resolution becomes higher, the contact area tends to become independent from the resolution.

Originality/value

The originality of the paper lies on the results and the corresponding conclusions obtained for the case of inelastic material behaviour, while the results for the case of elastic analysis verify the findings of other researchers.
Optimum energy on the fragmentation of kidney stones by direct impact
Authors: Caballero Antonio , Molinari Jean‐Francois
Published: August 2011

Purpose

This paper aims to describe a numerical approach to the fragmentation of kidney stones by direct impact.

Design/methodology/approach

The numerical approach consists of a Lagrangian finite element formulation with dynamic insertion of cohesive‐free surfaces. Cohesive free surfaces are governed by a damage constitutive model whereas the continuum part of the mesh remains linear elastic. The impact of the metallic probe of the medical device is modeled with a displacement control of the nodes inside the area of impact on the stone.

Findings

The results show the relation between the total energy transmitted during the impact with the damage and the fragmentation (number of fragments and number of microcrack clusters) of the kidney stone. The paper establishes the existence of both, an activation and saturation energy level, that delimit a range optimum working energy transmitted during the impact. In particular, the computations show that, for the calcium oxalate monohydrate stone, the maximum energy supplied by the medical device (Lithoclast) coincides with the saturation energy level.

Originality/value

In medical investigations, the experimentation is always restricted to the availability of patients or specimens. In the particular case of the elimination of renal calculi, the literature exhibits an extensive number of works reporting the practical experience of medical doctors. However, there is still a lack of information that might help to understand and to improve the comminution of kidney stones.
Identification and prevention of “Black Pad” in Sn/Pb soldering
Authors: Hui Lee Kong
Published: August 2011

Purpose

The use of an electroless nickel/immersion gold (ENIG) surface finish comes with the inherent potential risk of Black Pad failures that can cause fracture embrittlement at the interface between the solder and the metal pad. As yet, there is no conclusive agreed solution to effectively eliminate Black Pad failures. The case studies presented are intended to add to the understanding of the Black Pad failure mechanism and to identify both the plating and the subsequent assembly processes and conditions that can help to prevent the likelihood of Black Pad occurring.

Design/methodology/approach

Scanning electron microscope (SEM) analysis of exposed pad surfaces on failed PCBs demonstrated a “mud‐crack” appearance, which is a characteristic of the Black Pad phenomenon. In addition, energy dispersive X‐ray (EDX) analysis was used to identify the elemental composition of the fractured layer between the Ni3P and Ni3Sn4 inter‐metallic compound, confirming the presence of Black Pad.

Findings

Grain boundaries or “mud‐cracks” that can be clearly seen in a top view of the failed pad surface and corrosion spikes in the failed pad surface, as evident from the cross‐section sample, should be used as a guideline to confirm Black Pad failures. Maintaining an optimum and well‐controlled EN and immersion gold bath, in addition to good process control prior to nickel‐gold deposition is recommended as the best approach for minimizing the occurrence of Black Pad failures.

Research limitations/implications

Only Sn/Pb soldering processes using ENIG PCBs or package substrates were evaluated and discussed. Thus, the current case studies do not encompass Black Pad failures with lead‐free soldering.

Practical implications

The work reported provides guidelines that can be used to identify Black Pad occurrence. It also proposes relevant approaches for minimizing the possible occurrence of Black Pad.

Originality/value

The findings of these studies provide a basic understanding of the Black Pad failure mechanism. Subsequently, both the plating and the ensuing assembly processes and conditions that can help to prevent the likelihood of Black Pad occurrence were identified.
Boundary scan based testing algorithm to detect interconnect faults in printed circuit boards
Authors: Sharma D.K. , Sharma R.K. , Kaushik B.K. , Kumar Pankaj
Published: August 2011

Purpose

This paper aims to address the various issues of board‐level (off‐chip) interconnects testing. A new algorithm based on the boundary scan architecture is developed to test off‐chip interconnect faults. The proposed algorithm can easily diagnose which two interconnects are shorted.

Design/methodology/approach

The problems in board‐level interconnects testing are not simple. A new algorithm is developed to rectify some of the problems in existing algorithms. The proposed algorithm to test board‐level interconnect faults is implemented using Verilog on Modelsim software. The output response of each shorting between different wires of different nodes is different, which is the basis of fault detection by the proposed algorithm. The test vectors are generated by the test pattern generator and these test vectors are different for different nodes. This work implements built in self test using boundary scan technique.

Findings

The dominant‐1 (wired‐OR, denoted as WOR), dominant‐0 (wired‐AND, denoted as WAND) and stuck‐at faults are tested using the proposed algorithm. The proposed algorithm is also compared with the several algorithms in the literature, i.e. modified counting, walking one's algorithm and others. This paper's results are found to be better than the existing algorithms.

Research limitations/implications

The limitation of the proposed algorithm is that, at any time, the faults on any seven nodes can be tested to avoid aliasing. So, the groups are formed out of total nodes, in a multiple of seven to carry out the testing of faults.

Practical implications

The proposed algorithm is free from the problems of syndromes and utilizes a smaller number of test vectors.

Originality/value

Various existing algorithms namely modified counting, walking one's algorithm and others are discussed. A new algorithm is developed which can easily detect board‐level dominant‐1 (WOR), dominant‐0 (WAND) and stuck‐at faults. The proposed algorithm is completely free from aliasing and confounding syndromes.
Reverse weekend effect, trading volume, and illiquidity
Authors: Brusa Jorge , Hernandez Rodrigo , Liu Pu
Published: August 2011

Purpose

The purpose of this paper is to examine whether the seasonal anomaly known as the reverse weekend effect detected at index level can also be observed at individual stock level.

Design/methodology/approach

This paper's methodology is based on the model first developed by Connolly and then employed by Chang, Pinegar, and Ravichandran in which returns are regressed against the dummy variable for Monday. In addition, the conditional variance is also included into the mean equation following Engle, Lilien, and Robins. Given the increasing evidence that equity returns are conditionally heteroskedastic, the paper includes in the conditional variance the lag of the squared residual from the mean equation (i.e. autoregressive conditional heteroskedasticity term introduced by Engle) and the previous period's forecast variance (i.e. the generalized autoregressive conditional heteroskedasticity term introduced by Bollerslev). Also, the paper controls for the different impact of good and bad news on the conditional variance following Glosten, Jaganathan, and Runkle.

Findings

It is found that the anomaly is widely distributed among large firms, not just confined to a few firms. The finding suggests that the anomaly at the index level is not driven by the extreme returns of a few firms. The paper also finds that the anomaly at the firm level is not evenly distributed across the weeks of the month. Furthermore, trading volume and illiquidity of individual firms can only partially explain the seasonal anomaly.

Originality/value

This paper extends the study of the reverse weekend effect in individual firms.
Reversal of the weekend effect in Canada: an empirical analysis
Authors: Nippani Srinivas , Greenhut John G.
Published: August 2011

Purpose

The purpose of the paper is to check for reverse weekend effect in the Canadian stock market.

Design/methodology/approach

T‐tests, non‐parametric tests and regressions were employed.

Findings

There is reverse weekend effect in the Canadian stock market. Canadian stocks are shown to exhibit the traditional weekend effect prior to 1988, dissipating after that year until 1998 and then reversing to become the first non‐US market for which a reverse weekend effect is found.

Originality/value

This is the first paper on the Canadian stock market looking at reversal.
Miniaturisation of electrical machines
Authors: Ponick Bernd
Published: August 2011

Purpose

Approaches for a miniaturisation of electrical machines that are based on an electromagnetic principle have to overcome numerous challenges. Some of these are only a result of the rules of growth (or shrinkage), some are a result of the micro technological fabrication processes. This paper aims to give an overview of the current state of the art including various examples of linear and rotating micro actuators that have been realised.

Design/methodology/approach

The paper presents details of further miniaturisation by using thin film technology for depositing and structuring soft magnetic and hard magnetic material as well as copper for conductors and insulation.

Findings

There are numerous limitations for the miniaturisation with respect to material properties, friction/guidance, etc. and this paper illustrates ways to overcome these limitations.

Originality/value

The paper presents a compact overview on the achievements gained in 12 years of research within a collaborative research centre of the German DFG.
Recent progress in wiring networks diagnosis for automotive applications
Authors: Smail M.K. , Pichon L. , Olivas M. , Auzanneau F. , Lambert M.
Published: August 2011

Purpose

Aging wiring in cars, aircraft, trains and other transportation means is identified as a critical security area. The purpose of this paper is to develop a new methodology for wire diagnosis allowing the detection, localization and characterization of the fault in wiring network.

Design/methodology/approach

The direct problem (propagation along the cables) is modelled by RLCG circuit parameters and the finite difference time domain method. This model provides a simple and accurate method to simulate time domain reflectometry (TDR) responses. Genetic algorithms are combined with this wire propagation model to solve the inverse problem and to deduce physical information's about defects from the reflectometry response.

Findings

The results show the applicability of an inverse procedure dedicated to TDR for the localization and characterization of defects in simple wires and faulty wiring networks. With experimental results, the paper demonstrates the accuracy which can be provided for wire diagnosis.

Practical implications

The work provides an efficient tool for the diagnosis of embedded wire networks.

Originality/value

In this paper, a new method is developed and applied to detect, characterize and localize the defects in wiring networks: an inverse procedure is introduced for wire diagnosis. The presented methodology is applied for complex network structures and with measurement data.
A statistical study of scattering in periodic and random helix layers
Authors: Meiners Christian , Jacob Arne F.
Published: August 2011

Purpose

This paper aims at providing information on scattering in layers composed of periodic and non‐periodic arrangements of small metal helices. Metal helices exhibit a pronounced resonance and are thus very effective scatterers.

Design/methodology/approach

Scattering is expressed in terms of multipole moments. Non‐periodic layers are investigated using the combination of periodic boundary conditions for sample configurations and averaging many of these configurations. The results and the methodology are compared to the well‐known Clausius‐Mossotti (CM) mixing rule and the assumptions and concepts therein. This is done to deepen the understanding of the scattering behavior.

Findings

The investigations show that only few multipole contributions are necessary to model the interaction correctly.

Originality/value

A systematic comparison of a full‐wave scattering theory and the fast CM mixing theory is conducted, providing some physical insight. From this, conclusions on the validity of the mixing approach are drawn.
Numerical modeling of a MEMS actuator considering several magnetic force calculation methods
Authors: Preisner Thomas , Bolzmacher Christian , Gerber Andreas , Bauer Karin , Quandt Eckhard , Mathis Wolfgang
Published: August 2011

Purpose

The purpose of this paper is to investigate the accuracy of different force calculation methods and their impact on mechanical deformations. For this purpose, a micrometer scaled actuator is considered, which consists of a micro‐coil and of a permanent magnet (PM) embedded in a deformable elastomeric layer.

Design/methodology/approach

For the magnetic field evaluation a hybrid numerical approach (finite element method/boundary element method (FEM/BEM) coupling and a FEM/BEM/Biot‐Savart approach) is used, whereas FEM is implemented for the mechanical deformation analysis. Furthermore, for the magneto‐mechanical coupling several force calculation methods, namely the Maxwell stress tensor, the virtual work approach and the equivalent magnetic sources methods, are considered and compared to each other and to laboratory measurements.

Findings

The numerically evaluated magnetic forces and the measured ones are in good accordance with each other with respect to the normal force acting on the PM. Nevertheless, depending on the used method the tangential force components differ from each other, which leads to slightly different mechanical deformations.

Research limitations/implications

Since the force calculations are compared to measurement data, it is possible to give a suggestion about their applicability. The mechanical behavior of the actuator due to the acting forces is solely calculated and therefore only an assumption concerning the deformation can be given.

Originality/value

A new kind of micrometer scaled actuator is numerically investigated by using two different hybrid approaches for the magnetic field evaluation. Based on those, the results of several force calculation methods are compared to measurement data. Furthermore, a subsequent structural analysis is performed, which shows slightly different mechanical deformations depending on the used force calculation method.
Time and Laplace‐domain methods for MTL transient and sensitivity analysis
Authors: Brančík Lubomír
Published: August 2011

Purpose

The purpose of this paper is to present the development and comparison of selected time‐domain and Laplace‐domain methods for the simulation of waves propagating along multiconductor transmission lines (MTLs), both uniform and nonuniform, and sensitivities with respect to distributed and lumped parameters of MTL systems.

Design/methodology/approach

A methodology is based on discrete, semidiscrete and continuous MTL models formulated and solved both in the time and Laplace domains, latter combined with a numerical inverse Laplace transform (NILT).

Findings

The most accurate method is that based on the MTL Laplace‐domain continuous model, processed via the MTL chain matrix and connected with an NILT. This method concurrently shows minimal RAM requirements, and in case of uniform MTLs, it runs fastest. For nonuniform MTLs, however, the implicit Wendroff formula is fastest, as long as the RAM is available.

Research limitations/implications

The research is limited to linear MTLs only and the methods suppose terminating circuits based on their generalized Thévenin equivalents. They can be, however, generalized for more complex systems via more sophisticated boundary conditions treatment. The time‐domain methods have further potential to be generalized towards nonlinear MTLs.

Practical implications

The methods considered can contribute to solving signal integrity issues in high‐speed electronic systems, the Matlab routines developed can serve in education process as well.

Originality/value

The implicit Wendroff formula has been adapted to enable simulation of voltage and/or current distributions and their sensitivities along the nonuniform MTLs' wires. Besides, semidiscrete and continuous nonuniform MTL models have been elaborated to enable sensitivities determination, both in the time and Laplace domains, latter connected with the NILT technique based on fast Fourier transform/inverse fast Fourier transform and quotient‐difference algorithms.
Position determination based on electrical capacitance tomography
Authors: Gebhardt Stefan , Scheinert Gernot
Published: August 2011

Purpose

The purpose of this paper is to calculate the two‐dimensional (2D) centre position of objects with known shapes based on the reconstruction image of a square sensing area estimated with simulated and measured data by using electrical capacitance tomography (ECT).

Design/methodology/approach

A 2D electrostatic finite element model is used to calculate the capacitances between electrode pairs. A reconstruction algorithm with low computation time provides suitable images for subsequent image processing techniques. The results based on numerical data are verified by measurements.

Findings

It is possible to calculate the centre position of up to four rods (cross‐sectional area about 5 per cent of the measuring area) with an accuracy of 3 per cent in both coordinate directions related to the dimensions of the measuring area.

Originality/value

The paper presents an efficient method for position determination of several objects with known shape and uniform permittivity distribution by using ECT measurements with low‐cost electronic for industrial application.
Mutual impedance calculation between buried conductors of finite length
Authors: Rallis Konstantinos , Theodoulidis Theodoros
Published: August 2011

Purpose

The paper aims to develop expressions for calculating the mutual impedance between isolated conductors buried in homogeneous earth. The conductors have finite length and arbitrary position.

Design/methodology/approach

The conductors are represented by the use of elementary electric dipoles. Well‐known existing expressions are employed for the electric field of these dipoles. The induced voltages are evaluated and the final expressions for the mutual impedance are derived. The resulting expressions involve infinite double integrals, evaluated by using adaptive quadratures that are, however, time consuming. Therefore, an alternative approach is followed involving Sommerfeld integrals (SI) for representing the electric field of a dipole and a recently devised method for computing the SI, in the spatial domain, by using calculation of discrete complex images.

Findings

Final expressions for parallel and perpendicular conductors were derived and numerical results for several values of frequency, conductors' length and horizontal distance between them, were produced. Comparison to results produced with the well‐known Pollaczek formula showed excellent agreement.

Research limitations/implications

For future research, it is possible to use the developed expressions for earthing systems study, where the grounding grid is discretized and the moment method is invoked.

Originality/value

Currently, the formulas used for calculating mutual impedance are valid for parallel conductors of infinite length. With the present work, accurate expressions are given for finite length and arbitrary horizontal positioned conductors. In addition, the use of SI and the discrete complex image method results in a rapid and efficient tool for massive impedance calculations.
A straightforward deduction of the electric circuit power
Authors: Guarnieri Massimo
Published: August 2011

Purpose

The paper seeks to do the following. To provide an expression of the electromagnetic power flow that is alternative to the Poynting's theorem expression, overcomes its postulate feature, and is particularly suitable for electric circuit elements.

Design/methodology/approach

The paper proceeds from fundamental electromagnetic laws and, independently of Poynting's formulation, follows an approach that generalize established double formulations of the electrostatic and magnetostatic energies.

Findings

The paper proposes a compact and straightforward expression of the electromagnetic power flow based on the fundamental electromagnetic field sources, i.e. charge and current densities.

Practical implications

The achieved expression confirms Poynting's expression in the case of electric elements, overcoming its arbitrariness, generalizes previous partial results by other authors, deduced via the Poynting's power balance.

Originality/value

Is promising in the computation of power flow electromagnetic devices connected in electrical circuits, i.e. for coupled problems where the analysis of electromagnetic system interfaced to electric circuits is required. Due to its simple structure and straightforward deduction it has educational value to demonstrate the expressions of the electric power in circuit elements.
Discontinuous piecewise‐linear discrete‐time dynamics – maps with gaps in electronic systems
Authors: Feely Orla
Published: August 2011

Purpose

Many important electronic systems are modelled by discrete‐time equations with nonlinearities that are discontinuous and piecewise‐linear, often arising as a result of quantization. Approximations based on linearization – the standard engineering response to nonlinearity – are often quite unhelpful in these systems, because of the form of the nonlinearity. Certain methods and results have been developed over a number of years for the analysis of discontinuous piecewise‐linear discrete‐time dynamics. The aim of this tutorial paper is to review that body of knowledge, and to show how it can be applied to representative electronic systems.

Design/methodology/approach

The paper uses an important electronic circuit – the ΣΔ modulator – as a central example, and considers the dynamical behaviour exhibited by this circuit and related circuits.

Findings

The circuits under investigation exhibit complex forms of behaviour that can be explained by the application of methods of nonlinear discrete‐time dynamics.

Originality/value

This paper is intended to provide a brief introduction to the body of research that exists into the behaviour of nonlinear discrete‐time circuits and systems with discontinuous piecewise‐linear nonlinearities.
Foundations of network theory
Authors: Reibiger Albrecht
Published: August 2011

Purpose

Different axiomatizations of network theory are considered. Kirchhoff networks are regarded with priority. Multipole and multiport networks are introduced as alternative variants. Additionally, Minty and Paynter networks, which are always dualizable are discussed briefly. The latter are special cases of Kirchhoff as well as of multiport networks. This paper seeks to discuss these issues.

Design/methodology/approach

The paper develops network theory inside of set theory, i.e. networks, multipoles, etc. are defined as objects of set theory. As such objects we use preferably ordered pairs, ordered triples, etc. The objects of network theory are then separated from the class of all these set theoretical objects by means of some defining conditions. These conditions are the axioms of our approaches to network theory.

Findings

It is shown that all presented variants of axiomatizations can be developed on the basis of a uniform representation for the time functions for voltages and currents. All these variants allow interdisciplinary applications of network theory and they can be generalized to multidimensional networks. An interesting byproduct is the relationship between multiport networks, networks in Belevitch normal form, Paynter networks, and bond graphs.

Originality/value

For applications it is essential that Kirchhoff and multipole networks are with respect to their modeling capability of equal value. But from the foundational point of view the multipole terminology has a number of crucial disadvantages compared with that based on Kirchhoff networks. This fact is important both for the conception of circuit simulation software packages and for the development of basic circuit theory curricula.
CNN‐based ultrafast solver of stiff ODEs and PDEs for enabling realtime Computational Engineering
Authors: Chedjou J.C. , Kyamakya K.
Published: August 2011

Purpose

This paper seeks to develop, propose and validate, through a series of presentable examples, a comprehensive high‐precision and ultra‐fast computing concept for solving stiff ordinary differential equations (ODEs) and partial differential equations (PDEs) with cellular neural networks (CNN).

Design/methodology/approach

The core of the concept developed in this paper is a straight‐forward scheme that we call “nonlinear adaptive optimization (NAOP)”, which is used for a precise template calculation for solving any (stiff) nonlinear ODEs through CNN processors.

Findings

One of the key contributions of this work (this is a real breakthrough) is to demonstrate the possibility of mapping/transforming different types of nonlinearities displayed by various classical and well‐known oscillators (e.g. van der Pol‐, Rayleigh‐, Duffing‐, Rössler‐, Lorenz‐, and Jerk‐ oscillators, just to name a few) unto first‐order CNN elementary cells, and thereby enabling the easy derivation of corresponding CNN‐templates. Furthermore, in case of PDEs solving, the same concept also allows a mapping unto first‐order CNN cells while considering one or even more nonlinear terms of the Taylor's series expansion generally used in the transformation of a PDEs in a set of coupled nonlinear ODEs. Therefore, the concept of this paper does significantly contribute to the consolidation of CNN as a universal and ultra‐fast solver of stiff differential equations (both ODEs and PDEs). This clearly enables a CNN‐based, real‐time, ultra‐precise, and low‐cost Computational Engineering. As proof of concept a well‐known prototype of stiff equations (van der Pol) has been considered; the corresponding precise CNN‐templates are derived to obtain precise solutions of this equation.

Originality/value

This paper contributes to the enrichment of the literature as the relevant state‐of‐the‐art does not provide a systematic and robust method to solve nonlinear ODEs and/or nonlinear PDEs using the CNN‐paradigm. Further, the “NAOP” concept developed in this paper has been proven to perform accurate and robust calculations. This concept is not based on trial‐and‐error processes as it is the case for various classes of optimization methods/tools (e.g. genetic algorithm, particle swarm, neural networks, etc.). The “NAOP” concept developed in this frame does significantly contribute to the consolidation of CNN as a universal and ultra‐fast solver of nonlinear differential equations (both ODEs and PDEs). An implantation of the concept developed is possible even on embedded digital platforms (e.g. field‐programmable gate array (FPGA), digital signal processing (DSP), graphics processing unit (GPU), etc.); this opens a broad range of applications. On‐going works (as outlook) are using NAOP for deriving precise templates for a selected set of practically interesting PDE models such as Navier Stokes, Schrödinger, Maxwell, etc.
Analysis of transistor circuits having multiple DC solutions with the thermal constraint
Authors: Tadeusiewicz Michał , Hałgas Stanisław
Published: August 2011

Purpose

The purpose of this paper is to develop a method for finding all the DC solutions in nonlinear circuits with the thermal constraint.

Design/methodology/approach

The proposed approach employs an algorithm for finding all the DC solutions without thermal constraint, including a new contraction and elimination method, an efficient method for tracing characteristics expressing voltages and power in terms of temperature, and electrical analog of the chip thermal behavior.

Findings

The paper brings a method that guarantees finding all the DC solutions, considering thermal behavior of the chip, in mid‐scale practical transistor circuits.

Originality/value

A new contraction and elimination method, being the core of the algorithm for finding all the DC solutions, is proposed. An approach enabling us to consider a feedback between the power dissipated inside the chip and the temperature, which affects the circuit parameters and consequently the solutions is developed.
Neural predictors and wavelet transformation for forecasting the PM10 pollution
Authors: Siwek Krzysztof , Osowski Stanislaw , Sowinski Mieczyslaw
Published: August 2011

Purpose

The aim of this paper is to develop the accurate computer method of predicting the average PM10 pollution for the next day on the basis of some measured atmospheric parameters, like temperature, humidity, wind, etc. This method should be universal and applicable for any place under consideration.

Design/methodology/approach

The paper presents the new approach to the accurate forecasting of the daily average concentration of PM10. It is based on the application of the ensemble of neural networks and wavelet transformation of the time series, representing PM10 pollution.

Findings

On the basis of numerical experiments, the paper finds that application of many neural predictors cooperating with each other can significantly improve the quality of results. The paper shows that the developed forecasting system checked on the data of PM10 pollution in Warsaw generated good overall accuracy of prediction in terms of root mean squared error, mean absolute error and mean absolute percentage error.

Originality/value

The main novelty of the proposed approach is the application of the wavelet transformation and many neural networks organized in the form of ensemble. The individual neural predictors are integrated into one forecasting system using different forms of integrations, including the blind source separation method and neural‐based integration.
Optimum exciter design for Magnetic Induction Tomography (MIT)
Authors: Ziolkowski Marcin , Gratkowski Stanislaw
Published: August 2011

Purpose

The purpose of this paper is to present the methodology of designing an exciter for Magnetic Induction Tomography (MIT). The design of the exciter must satisfy the following requirements: maximize MIT system sensitivity and minimize harmful influence on electronic MIT equipment.

Design/methodology/approach

Two objective functions are considered, namely: a magnetic flux density in the protected regions and a module of the eddy‐current density vector in the object under test in the vicinity of a sensor. The paper shows a multi‐objective optimization technique (based on the weighted sum method) which, by coupling the finite‐element method with a genetic algorithm, supports the design of the exciter.

Findings

It is possible to design in a relatively simple way an exciter for MIT under the given assumptions.

Originality/value

Detailed description of the multi‐objective optimization procedure has been presented.
Experimental evaluation of the current‐phase relation of a Josephson junction
Authors: Wetzstein Olaf , Ortlepp Thomas , Uhlmann Hermann F. , Toepfer Hannes
Published: August 2011

Purpose

Josephson junctions act as active elements in superconducting electronics. The behavior of this nonlinear element is characterized by the relation between current and the quantum mechanical phase‐difference. For an accurate device modeling, detailed knowledge about this relation is necessary. This paper aims to discuss these issues.

Design/methodology/approach

To obtain detailed information, a method for DC measurement of the current‐phase relation suitable for all kinds of superconducting circuit elements was accomplished.

Findings

The authors developed a linear transformation algorithm to calculate the current‐phase relation from the measured data.

Research limitations/implications

It turns out that in future designs additional connections and special test structures are required to gain more knowledge about inductance values required for the algorithm.

Originality/value

Based on the inverse calculation of that algorithm, the authors found a 7 percent deviation of the current‐phase relation of a standard superconductor/insulator/superconductor Josephson junction from the predicted sine‐wave behavior. Furthermore, the paper suggests to use this method to evaluate the current‐phase relation of new Josephson elements such as a superconductor/ferromagnet/superconductor junction. Therefore, the authors will deposit the new element directly on the chip with the test setup fabricated with standard Nb‐technology.
Robust contrast enhancement by a coupled oscillatory paradigm
Authors: Latif M.A. , Chedjou J.C. , Kyamakya K.
Published: August 2011

Purpose

An image contrast enhancement is one of the most important low‐level image pre‐processing tasks required by the vision‐based advanced driver assistance systems (ADAS). This paper seeks to address this important issue keeping the real time constraints in focus, which is especially vital for the ADAS.

Design/methodology/approach

The approach is based on a paradigm of nonlinear‐coupled oscillators in image processing. Each layer of the colored images is treated as an independent grayscale image and is processed separately by the paradigm. The pixels with the lowest and the highest gray levels are chosen and their difference is enhanced to span all the gray levels in an image over the entire gray level range, i.e. [0 1]. This operation enhances the contrast in each layer and the enhanced layers are finally combined to produce a color image of a much improved quality.

Findings

The approach performs robust contrast enhancement as compared to other approaches available in the relevant literature. Generally, other approaches do need a new setting of parameters for every new image to perform its task, i.e. contrast enhancement. These approaches are not useful for real‐time applications such as ADAS. Whereas, the proposed approach presented in this paper performs contrast enhancement for different images under the same setting of parameters, hence giving rise to the robustness in the system. The unique setting of parameters is derived through a bifurcation analysis explained in the paper.

Originality/value

The proposed approach is novel in different aspects. First, the proposed paradigm comprises of coupled differential equations, and therefore, offers a continuous model as opposed to other approaches in the relevant literature. This continuity in the model is an inherent feature of the proposed approach, which could be useful in realizing real‐time image processing with an analog implemented circuit of the approach. Furthermore, a novel framework combining coupled oscillatory paradigm and cellular neural network is also possible to achieve ultra‐fast solution in image contrast enhancement.
Linking supply chain management with mass customization capability
Authors: Liu Gensheng (Jason) , Deitz George D.
Published: August 2011

Purpose

The purpose of this paper is to explore the role of supply chain management in enabling manufacturers' mass customization capabilities.

Design/methodology/approach

This paper is based upon survey data from 262 manufacturing plants, spanning nine countries and three industries. Responses from multiple employees were aggregated for each item. Hypothesized relationships between variables were analyzed using structural equation modeling.

Findings

The results generally indicate that plant mass customization capabilities are driven by customer‐focused product design and reduced supplier lead times. In turn, these factors are driven by management's emphasis on supply chain planning. Post hoc tests show that the effects of supply chain planning on mass customization capabilities are fully mediated by customer‐focused product design and reduced supplier lead time.

Originality/value

While the literature suggests that mass customization depends upon a dynamic extended enterprise, extant empirical work has focused on internal firm characteristics. The paper is among the first to examine the significance of supply chain management upon the development of mass customization capabilities.
Stakeholder perceptions of green marketing: the effect of demand and supply integration
Authors: Kirchoff Jon F. , Koch Chris , Satinover Nichols Bridget
Published: August 2011

Purpose

The purpose of this paper is to extend the stream of thought regarding the concept of demand and supply integration (DSI) within the domain of environmental responsibility and green marketing.

Design/methodology/approach

Conceptual application of theory to strategic‐level concepts is used to develop propositions representing a theoretical approach to the integration of green marketing and green supply chain management (SCM).

Findings

Based on stakeholder theory, the authors propose that greater value will be perceived by customer stakeholders when the firm is able to successfully manage and coordinate demand (marketing) and supply (SCM) functions, ensuring that customer stakeholders receive what they are promised in regard to environmental products and services. For this relationship to offer competitive advantage and higher firm performance, the authors contend that it is necessary to better understand how customer stakeholders perceive firms' environmental initiatives, and to investigate if the degree to which a firm's demand and supply functions are integrated influences these perceptions.

Research limitations/implications

Scholars will benefit from ideas and questions put forth in this paper as it suggests specific avenues to pursue empirically in order to understand stakeholder perceptions of a firm's environmental responsibility activities.

Practical implications

Managers will benefit from the results of this paper by better understanding the benefits of DSI in creating marketing campaigns for environmental products and services that stakeholders perceive as legitimate.

Originality/value

The authors introduce the concept of DSI to the green marketing and green SCM literature and position DSI within the broader rubric of environmental commitment in the firm.
Technology emergence between mandate and acceptance: an exploratory examination of RFID
Authors: Kros John F. , Glenn Richey R. , Chen Haozhe , Nadler S. Scott
Published: August 2011

Purpose

The purpose of this paper is to focus on radio frequency identification (RFID) acceptance and examine three understudied drivers: a company's satisfaction with existing logistics technologies, its logistics technology readiness (technology optimism and technology innovativeness), and relationship hostage position. The proposed conceptual model also investigates the impacts of RFID acceptance and these three antecedents on the company's logistics performance.

Design/methodology/approach

Survey data were collected from the members of three professional associations in the USA. Structural equation modeling was used to test the proposed relationships.

Findings

According to the analysis results, a company's satisfaction with existing technology has negative impact on RFID acceptance, and technology readiness has positive impact on RFID acceptance. However, the relationship between a company's hostage position and RFID acceptance was found to be only partially significant. Also, the positive relationship between a company's RFID acceptance and its logistics performance is confirmed in this study. Furthermore, while a company's satisfaction with existing technology and technology innovativeness were found to be positively related to logistics performance, its technology optimism and hostage position were not significant related to its logistics performance.

Practical implications

This research confirms that a company's RFID acceptance is positively related to logistics performance. Therefore, even if a company is satisfied with its existing technologies, careful evaluation is warranted to determine if RFID as a new technology is needed to maintain the company's logistics performance in a dynamic environment. Also, this research suggests that supply chain members should be extremely cautious about the power usage toward its partners, because the authors' results show that forcing other partners to take cooperative actions may not yield the desired results.

Originality/value

This is first study examining RFID technology through a behavioral perspective. A new construct, RFID acceptance, was proposed, and related measurement scale was developed and tested along with its antecedents and outcomes.
Land and labour: The value of assets
Authors: Beukes C.J.
Published: August 2011

Stakeholders are entitled to be properly informed about their interests in an enterprise, not only in terms of the cost of assets such as land and labour, but also in terms of the value of these assets. The value of land could be influenced by environmental pollution, damages and rehabilitation activities, which should be accounted for in financial and non‐financial terms. In contrast to the tendency to calculate and include only the cost of labour, the value of labour should also be determined to include aspects such as knowledge, skills, organising proficiency and customer relations.
Environmental reporting in South Africa from 1994 to 1999: A research note
Authors: de Villiers C.J. , Barnard P.
Published: August 2011

The content of the annual reports of listed South African mining companies from 1994 to 1999 was analysed to determine how many disclose certain environmental information. This number, expressed as a percentage, was compared with the corresponding percentage disclosure among the Financial Mail Top 100 industrial companies for the same years. A greater number of mining companies, when compared to other large companies, disclose environmental information. This finding is consistent with legitimacy, which is the notion that an organisation will not continue to prosper if its aims and methods are in conflict with that of society. Mining companies have a greater need to legitimise their operations by means of environmental disclosure, because their environmental impact is extensive and obvious.