bluuebunny/crossref_metadata_2025 huggingface dataset:
Activity of fillers in elastomer networks of different structure
Authors: Zaborski M. , Donnet J.B.
Published: June 2003

The paper deals with interactions between low molecular weight substances and silica. Activity of SiO2 towards ethylene‐propylene‐diene rubber (EPDM) also depends on the kind of crosslinking system used. Calcium carbonate, the filler exhibiting low interactions with elastomers does not show any changes in activity, due to application of different crosslinking systems. In our opinion, the observed increase of the fillers activity results from the modification of elastomer chains by crosslinking agents, influence of the latter on the formation of its own network (the so called “structure”) in the elastomer matrix, and above all from nanoheterogeneous distribution of network crosslinks in vulcanizates. The non Gaussian probably bimodal distribution of crosslinks is likely to influence positively properties of elastomers. A similar effect is observed in peroxide vulcanizates of EPM produced with the use of the crosslinking coagents of polar nature. Behaviour of different kinds of carbon black in natural rubber (NR) crosslinked with dicumyl peroxide (DCP), sulphur donors or sulphur with accelerators is discussed. Reinforcing action of carbon black, particularly the active ones, showed to be more effective in sulphur than in peroxide vulcanizates.
External management succession, human capital, and firm performance: an integrative analysis
Authors: Bailey Elizabeth E. , Helfat Constance E.
Published: June 2003

Economic analysis of human capital leads to a somewhat different question than that addressed by other management research on external succession: do differences between external successors in the transferability of their human capital affect firm performance, and if so, how? By comparing external successors that have within‐industry and related‐industry skills, we find that successors with less transferable (related‐industry) skills have greater variance of firm performance. Our analysis provides an example of the benefits of integrating economic concepts with empirical research in competitive strategy, on a topic of central concern in the traditional strategic management literature, namely, top executives. Copyright © 2003 John Wiley & Sons, Ltd.
The intermediation theory of the firm: integrating economic and management approaches to strategy
Authors: Spulber Daniel F.
Published: June 2003

Economic and management perspectives on management strategy can and should be integrated. The intermediation theory of the firm and models of market microstructure provide a basis for advancing the integration of management and economics perspectives. In particular, the theory allows for a combination of economic approaches such as Porter's work on competitive strategy with management approaches such as work on the abilities and resources of the organization. The article presents a unified strategy framework based on transaction costs and the intermediation theory of the firm. Copyright © 2003 John Wiley & Sons, Ltd.
Strategy as economics versus economics as strategy
Authors: Langlois Richard N.
Published: June 2003

Clearly, strategy and economics differ along one critical dimension: strategy is concerned descriptively with firms and normatively with the tasks of managers, whereas economics is concerned descriptively with the entire economic system and normatively with the efficiency of that system. Nonetheless, the overlap is considerable, and both management scholars and economists have ransacked economic thought for inspirations to strategic theory and managerial practice. This essay will examine and evaluate that enterprise. More interestingly, perhaps, it will suggest that perhaps the process ought to be reversed. Economics as it is now practiced would do well to learn from strategy. Copyright © 2003 John Wiley & Sons, Ltd.
The resource‐based tangle: towards a sustainable explanation of competitive advantage
Authors: Foss Nicolai J. , Knudsen Thorbjørn
Published: June 2003

To advance the RBV we propose separation of necessary and additional conditions for the expression of SCA. We argue that there are only two necessary conditions, namely uncertainty and immobility and that all other conditions are additional. Copyright © 2003 John Wiley & Sons, Ltd.
Why look for a mirage when you already have an oasis?
Authors: Pandian J. Rajendran , Robertson Paul L.
Published: June 2003

The theoretical elegance of economic theory in general has inspired many strategic management researchers to examine the possibilities of building theories of competitive strategy by applying economic principles to competitive decisions. In this paper, we argue that the integration of economic perspective is not feasible. Also, we argue that the theories built on strategic management perspectives are superior to those built on economic theory and hence we should not worry about integrating these two competing perspectives. We also point to the issues raised by these attempts at integration and point out the difficulties involved. Our arguments are supported by other researchers who have attempted to reconcile differences in various economic traditions. Hence, we ask why we should search for a mirage (though one might imagine it to be an oasis) while we are already at an oasis! Copyright © 2003 John Wiley & Sons, Ltd.
Integrating transaction costs theory and real options theory
Authors: Sanchez Ron
Published: June 2003

This paper develops an integration of transactions costs theory and real options theory that leads to a more complete representation of the problem of economic organizing. By recognizing the opportunity costs associated with internalization of specific‐use assets when flexible assets are also available, the integrated theoretical framework provides better insights into optimal strategies for configuring value chains under supply‐side and demand‐side uncertainty. This expanded model of economic organizing suggests four optimal strategies for configuring value chains and predicts four prevailing forms of economic organization under varying combinations of contracting (supply‐side) and market (demand‐side) uncertainty. Copyright © 2003 John Wiley & Sons, Ltd.
A subjectivist approach to strategic management
Authors: Fu‐Lai Yu Tony
Published: June 2003

Acknowledging the shortcomings of contemporary research on the economics of strategy, this paper proposes a subjectivist approach to strategic management. This subjectivist perspective is originated in German economics and found its base in the Austrian school of economics. Based largely on the works on Max Weber, Alfred Schutz and Ludwig von Mises, this paper develops a subjective interpretation framework which is applied to various fields of strategic management: entrepreneurship, organisation, vertical integration, innovation, marketing and advertising. Copyright © 2003 John Wiley & Sons, Ltd.
Unraveling the resource‐based tangle
Authors: Peteraf Margaret A. , Barney Jay B.
Published: June 2003

Resource‐based theory (RBT) is a prime example of a theory that integrates a management perspective with an economics perspective. As such, its challenge is to keep its arguments logically consistent and clear, despite the risk of their becoming entangled, due to competing and possibly conflicting theoretical influences. We argue, in this paper, that to meet this challenge, it is essential to understand the limits to the domain of RBT. Unless RBT is understood as a resource‐level and efficiency‐oriented analytical tool, its contribution cannot be understood and appreciated fully. Incorporating aspects of economic theory that fall outside this domain will not increase its power and will only add to the confusion.

Continued efforts to increase the analytic precision of RBT and to elaborate its economic logic, however, are worthwhile pursuits. To these aims, then, we provide a sharper definition of competitive advantage, linking this term to value creation and to demand side concerns. Similarly, we provide an economically meaningful definition of value and more precise definitions of critical resources and of economic rents. This allows us to trace a clearer trail of logic, consistent with both the management and the economics perspectives, leading from critical resources to the generation of rents. Copyright © 2003 John Wiley & Sons, Ltd.
The emergent knowledge‐based theory of competitive advantage: an evolutionary approach to integrating economics and management
Authors: Coff Russell W.
Published: June 2003

This article explores the intersection of management and economics in the strategic management literature. Specifically, it examines knowledge‐based advantages from management and economics perspectives to highlight differences in explanations of: (1) the source of an advantage, (2) determinants of sustainability of an advantage, and (3) the factors that predict rent appropriation patterns from a competitive advantage.

I conclude that both perspectives contribute to our understanding of why firms perform differently. Furthermore, the gradual or evolutionary integration that has occurred over time is effective and efficient for exploring the nature of strategic management problems. Finally, the dynamic competitive and technological environment will continue to yield new opportunities for integration of theoretical approaches. Copyright © 2003 John Wiley & Sons, Ltd.
Time domain modeling of electromagnetic wave propagation in Tellegen media
Authors: Barba I. , Grande A. , Cabeceira A. C. L. , Represa J.
Published: June 2003

A time‐domain solution of electromagnetic wave propagation in Tellegen materials is presented. The angle tilt between electric and magnetic fields, the phase speed of the wave, and the intrinsic impedance are computed when the medium is excited with a monochromatic source. The results are in good agreement with theoretical predictions. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 167–168, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11004
Particle swarm optimization for reconfigurable phase‐differentiated array design
Authors: Gies Dennis , Rahmat‐Samii Yahya
Published: June 2003

Multiple‐beam antenna arrays have important applications in communications and radar. This paper describes a method of designing a reconfigurable dual‐beam antenna array using a new evolutionary algorithm called particle swarm optimization (PSO). The design problem is to find element excitations that will result in a sector pattern main beam with low side lobes with the additional requirement that the same excitation amplitudes applied to the array with zero phase should result in a high directivity, low side lobe, and pencil‐shaped main beam. Two approaches to the optimization are detailed. First, the PSO is used to optimize the coefficients of the Woodward–Lawson array synthesis method. Second, the element excitations will be optimized directly using PSO. The performance of the two methods is compared and the viability of the resulting designs are discussed in terms of sensitivity to errors in the excitation. Additionally, a parallel version of the particle swarm code developed for a multi‐node Beowulf cluster and the benefits that multi‐node computing bring to global optimization will be discussed. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 168–175, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11005
Thin absorbing structure for all incidence angles based on the use of a high‐impedance surface
Authors: Tretyakov S. A. , Maslovski S. I.
Published: June 2003

It is shown that thin mushroom layers (high‐impedance surfaces realized as regular arrays of small patches at a small distance from a metal surface) can be used as radar‐absorbing structures whose performance does not change with the incidence angle for TM‐polarized waves. The key role of the vias connectors between the patches and the ground plane is explained, and potential performance demonstrated in examples. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 175–178, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11006
LTCC broadband deep embedded interconnects (DEI) with application for embedded bandpass filter
Authors: Yu J. J. , Tan B. T. , Chew S. T.
Published: June 2003

Careful design of via transitions intended for use in practical microwave applications is needed to realize the advantages of low‐temperature co‐fired ceramic (LTCC), such as highly integrated buried passive circuits. Grounded coplanar waveguide (GCPW) to asymmetrical stripline vertical interconnects is optimized for thick LTCC substrate. The focus is to develop a vertical transition through thick substrate supporting deep embedded interconnects (DEI). The measured results demonstrate vertical transitions with good performance up to 20 GHz. Embedded LTCC bandpass filter with such vertical transition has been demonstrated with an insertion loss of 2.2 dB and return loss better than −20 dB at 16.2 GHz. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 179–181, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11007
A comprehensive study and modeling of centre‐tap differentially driven single‐turn integrated inductors for 10‐GHz applications
Authors: Lim S. F. , Yeo K. S. , Ma J. G. , Do M. A. , Geng C. Q. , Chew K. W. , Chu S.‐F.
Published: June 2003

This paper presents a complete characterization of single‐turn differentially driven high‐quality (Q) factor inductors at 10 GHz. The separate characterization of individual physical dimension through a series of 3D electromagnetic (EM) simulations allows us to evaluate their effects on the inductor's Q and inductance L separately. The results show that single‐turn inductors can generate Q greater than 20 at 10 GHz with inductance L at the sub‐nano Henry range. Finally, a lumped‐element equivalent circuit of the inductor was developed for predicting associated Q, L, and frequency behavior. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 182–185, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11008
A compact bandpass filter using microstrip slow‐wave open‐loop resonators with high impedance lines
Authors: Oh Soonsoo , Kim Youngsik
Published: June 2003

In this paper, a bandpass filter using a microstrip slow‐wave open‐loop resonator with high impedance lines is presented. This resonator has the high impedance of a loaded microstrip line, which significantly increases not only the slow‐wave effect but also the dispersion effect. These effects result in the reduction of its size and the widening of an upper stop‐band region compared to that of a conventional microstrip slow‐wave open‐loop resonator with a low impedance line. The new proposed filter and conventional filters are simulated and tested. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 185–187, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11009
On the relationship for the monostatic modulated fundamental scattering technique
Authors: Azaro Renzo , Caorsi Salvatore , Pastorino Matteo
Published: June 2003

In the monostatic modulated scattering technique for the measurement of electromagnetic fields, the reflected voltage is found to be proportional to the square amplitude of the unperturbed field at the probe position. In this paper, this fundamental relationship is simply derived by using the Lorentz reciprocity theorem and the concept of minimum scattering antenna. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 187–190, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11010
New CPW low‐pass filter based on a slow wave structure
Authors: Martín F. , Falcone F. , Bonache J. , Lopetegi T. , Laso M. A. G. , Sorolla M.
Published: June 2003

A new periodic loaded coplanar waveguide (CPW) low‐pass filter with very sharp cutoff has been designed and fabricated. The device consists of a CPW structure with T‐shaped periodic patterns on both the central strip and ground planes. With such a design, capacitive coupling is added between the signal strip and ground planes at periodic positions, resulting in a filtering action and slow‐wave effect. In addition to a sharp cutoff, the device exhibits very low insertion loss in the pass band, wide rejection bandwidth, and simple design and fabrication. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 190–193, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11011
On the field patterns of the dominant mode in unilateral finline by the finite‐element method
Authors: Lu Mai , Leonard Paul J.
Published: June 2003

In this paper, the field patterns of the dominant mode in unilateral finline are calculated by the hybrid finite‐element method. Dependence of the field patterns on thickness of metallic fins and dielectric constant of dielectric substrate are presented. The figures in this paper have important values in the design of finline millimeter wave integrated circuits. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 193–195, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11012
A novel single‐layer patch antenna for GSM/DCS dual‐band operation
Authors: Liu Ting Hua , Zhang Wen Xun
Published: June 2003

A novel dual‐band single‐layer patch antenna that covers the bands of 890–960 MHz for GSM and 1710–1880 MHz for DCS, with VSWR ⩽ 2:1, is presented. This antenna consists of a ground plane, air spacing (without dielectric substrate), and a metal patch layer printed on a thin substrate with lower permittivity. The performances simulated by using Ansoft Ensemble 8.0 software are bandwidth for the GSM band (9.22%) and 730 MHz for DCS band (40.56%). The simulated and experimental results are compared. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 195–198, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11013
A sparse matrix iterative approach for modeling tree scattering
Authors: Ding Kung‐Hau , Tsang Leung
Published: June 2003

In this paper we present a computational electromagnetic model for tree scattering at VHF/UHF frequencies. A structure model with dielectric cylinders is being used to simulate trees with bare branches. The method of moments (MoM) solution of the volume integral equation is computed for the tree scattering signature. An efficient numerical algorithm based on the sparse matrix iterative approach (SMIA) is used to solve the matrix equation. The SMIA decomposes the impedance matrix into a sparse matrix for the near interactions, and a complementary matrix for the far interactions among the cylindrical sub‐cells of the tree structure. Using a direct sparse solver to estimate the strong interaction part, we iteratively include the weak interaction contribution in order to update the solution. The key feature of the SMIA approach is that very little iteration is required to obtain convergent solutions. We have applied the SMIA tree scattering model to calculate scattering from various simulated trees with up to several hundreds of branches. Solutions obtained from the SMIA method agree very well with the solutions obtained using exact matrix inversion and the conjugate gradient method (CGM). Compared to the CGM, the SMIA approach reduces the number of iterations by a factor of more than a hundred and provides a much faster numerical solution scheme for computing tree scattering. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 198–202, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11014
Effect of ESD injection locations on induced noise inside a shielded enclosure
Authors: Chan K. H. , Fung L. C. , Leung S. W.
Published: June 2003

Electrostatic discharge (ESD) on the metallic enclosure of electronic products normally generates unwanted radiated electromagnetic interference (EMI). The radiated EMI penetrates through the apertures on the enclosure and then couples to the circuitries inside the enclosure. This may cause malfunction and signal errors to the circuitries. In this paper, an experimental investigation on the effects of induced noise level caused due to different injection locations of ESD on the metallic enclosure with different aperture sizes is carried out. Results show that the induced voltage is highly sensitive to injection location of ESD. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 203–206, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11015
Extended (FD)2TD formulations for lumped elements
Authors: Chen R. S. , Yung Edward K. N. , Chan C. H.
Published: June 2003

Currently extended finite‐difference time domain (FDTD) formulations require the permittivity and conductivity to be independent of frequency. However, for many real materials of interest, these parameters vary significantly with frequency. The extended frequency‐dependent finite‐difference time domain (FD)2TD method makes it possible to analyze hybrid integrated circuits with lumped element within dispersive medium by combining lumped parameters (R, C, or L) and frequency‐dependent dielectric substrate in the algorithm. This method allows the full‐wave analysis of virtually hybrid integrated circuits and gets parameters with a wide frequency range with one simulation. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 206–209, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11016
Simple analysis of the frequency modes for microstrip ring resonators of any general shape and correction of an error in the literature
Authors: Hsieh Lung‐Hwa , Chang Kai
Published: June 2003

Unlike the conventional magnetic‐wall model, a simple transmission‐line model unaffected by boundary conditions is used to calculate the frequency modes of ring resonators of any general shape such as annular, square, or meander. Moreover, it corrects an error in the literature concerning the frequency modes of the one‐port ring resonator. Also, it can be used to describe the dual‐mode behavior of the ring resonator, which the magnetic‐wall model cannot address well, especially for a ring resonator with complicated boundary conditions. Experiments show good agreement with theory. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 209–213, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11017
Scattering by screw heads in reflecting surfaces and their effect on the sidelobes of reflector antennas
Authors: Yang Jian , Kildal Per‐Simon
Published: June 2003

Screws are often used to fasten the main reflector of a reflector antenna to its support structure. The screw heads may then cause bumps in an otherwise smooth reflector surface. Thereby, they disturb the reflected fields and cause increased sidelobes. In this paper, a perturbation theory is introduced in order to calculate efficiently the increased sidelobes due to scattering from the screw heads. Screw heads are approximated as half spheres, whereby it becomes very efficient to calculate the scattering from them by using a spherical wave expansion algorithm, GIDMULT. This method has been verified by measurements in a low sidelobe antenna. We also describe some ways to reduce the scattering, such as dielectric coating of the screw heads and optimization of their locations. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 213–217, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11018
Compact internal quad‐band antenna for mobile phones
Authors: Ang Irene , Guo Yong‐Xin , Chia M. Y. W.
Published: June 2003

A novel compact internal quad‐band handset antenna for covering GSM900, DCS1800, PCS1900, and ISM2450 bands is presented. Details of the antenna are discussed along with measured and simulated results. The simulation is based on the FDTD method. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 217–223, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11019
Diversity dual‐band planar inverted‐F antenna for WLAN operation
Authors: Wong Kin‐Lu , Chen Yen‐Yu , Su Saou‐Wen , Kuo Yen‐Liang
Published: June 2003

A printed diversity dual‐band planar inverted‐F antenna (PIFA) mounted vertically at the edge of a PCMCIA network card (such that the protruded portion of the network card from the housing of the laptop has a minimum length) for WLAN operation in the 2.4‐GHz band (2400–2484 MHz) and 5.2‐GHz band (5150–5350 MHz) is presented. The diversity antenna studied comprises two back‐to‐back stacked PIFAs and has a low profile of 10 mm to the network card. Across the two operating bands, the measured reflection coefficient S11 and isolation S21 are all less than −14 dB (1.5:1 VSWR) and −24 dB, respectively. In addition, the measured radiation patterns of the two stacked PIFAs in general cover complementary space regions, thereby making it possible for providing spatial diversity for WLAN operation. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 223–225, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11020
Relationship between the propagation characteristics of via and microstrip connecting angle
Authors: Ji Wusheng , You Bin , Wang Xuedong , Li Ying
Published: June 2003

The microstrip‐via‐microstrip is a popular interconnect structure in multilayer circuits at microwave frequency. The microstrip connecting angle is an arbitrary angle due to layout and technical error. The relationship between the propagation characteristics of via and the microstrip connecting angle was analyzed by using the Ansoft simulator. The obtained results have important application value for the design of a similar multilayer circuit. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 225–228, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11021
Studies on crossover and broadside‐coupled microstrip bandstop filters
Authors: Yang Ning , Chen Zhi Ning , Wang Yun Yi , Chia M. Y. W.
Published: June 2003

Two kinds of two‐layer microstrip structures, including crossover and broadside‐coupled microstrip lines, and their equivalent circuits, are studied based on a quasi‐static analyzing method. The shorting vias from the bottom strips to the ground planes are introduced to achieve bandstop. Simulated and measured results show the validity of the proposed structures and their CAD models for the design of bandstop filters. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 228–231, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11022
Modeling and design of interdigital capacitor based on neural networks and genetic algorithm
Authors: Chen R. S. , Zhang X. , Tsang K. F. , Yung K. N.
Published: June 2003

In this paper, a novel approach is described to design an interdigital capacitor (IDC) using artificial neural networks (ANNs) and genetic algorithm (GA). The scattering parameters of the training samples are computed by the finite‐difference time‐domain (FDTD) and ANN is applied to describe the models of IDC. According to the engineering requirement, the dimensions of IDC can be designed with GA using the trained ANN models. This design procedure is proved to be time saving and of high accuracy. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 231–235, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11023
Antenna‐coupled VOx thin‐film microbolometer array
Authors: González F. J. , Abdel‐Rahman M. , Boreman G. D.
Published: June 2003

Two‐dimensional arrays of log‐periodic antenna‐coupled microbolometers were fabricated using VOx and Nb thin films as bolometric materials, which have different temperature coefficients of resistance. Noise, response, and angular characteristics of both types of microbolometer arrays were measured and compared. VOx‐based devices presented a 4.5× better response and 5.5× better signal‐to‐noise ratio than Nb‐based devices. Radiation patterns show that a further increase in response can be obtained by better matching the VOx bolometer to the antenna elements. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 235–237, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11024
A novel accurate PEEC‐based 3D modeling technique for RF devices of arbitrary conductor‐magnet structure
Authors: Long Haibo , Feng Zhenghe , Feng Haigang , Wang Albert
Published: June 2003

This paper presents magPEEC, a new 3D electro‐magnetic modeling technique that extends the existing PEEC approach to analyze arbitrary conductor‐magnet structures by accounting for fictitious magnetized currents on a magnetic material surface. Applications for magnetic‐cored/layered spiral inductors demonstrate validity and accuracy of magPEEC. Possible solutions to improve RF IC inductors using magnetic cores are discussed. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 237–240, 2003; Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.11025
GSM base‐station antenna built using composite materials technology
Authors: Borowiec R. , Słobodzian P.
Published: June 2003

This paper presents some aspects concerning the use of composite materials for manufacturing microstrip antenna arrays, along with key problems related to the incorporation of such materials into antenna design. As an example, an integrated microstrip antenna array with electrically down‐tilted beam for the GSM900 system is described. The applicability of composite materials technology has been proven by mechanical strength test and electrical parameter measurement results, which are also briefly reported herein. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 240–244, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11026
A dual‐frequency triangular chip antenna for WLAN operation
Authors: Lee Gwo‐Yun , Chen Wen‐Shyang , Wong Kin‐Lu
Published: June 2003

This article presents a dual‐frequency triangular chip antenna suitable for WLAN operation in the 2.4‐GHz band (2400–2484 MHz) and 5.2/5.8‐GHz bands (5150–5350 MHz/5725–5875 MHz). The proposed triangular chip antenna in this study comprises a right‐angle, isosceles triangular FR4 base of thickness 1.6 mm and area 72 mm2 and, on the top surface of the FR4 base, a metal line pattern with two branch radiating strips is printed, which generates two separate wide resonant modes for the desired dual‐frequency WLAN operation. Experimental results of a constructed prototype mounted on one of the corners of a grounded substrate (about the size of a compact flash card) are presented and discussed. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 244–247, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11027
The effect of stimulated Raman scattering in WDM‐based IP backbone
Authors: Tang Junhua , Zhang Liren , Siew Chee‐Kheong
Published: June 2003

This paper focuses on the power depletion due to stimulated Raman scattering in a WDM link when bursty IP traffic is directly loaded. The actual power penalty due to stimulated Raman scattering is shown to be dependent on IP traffic load. The statistics of the power depletion due to stimulated Raman scattering under various traffic loading conditions are obtained and compared with the stimulated Raman scattering effect under the worst‐case assumption. This provides useful information for the network designers to adjust the power of input light accordingly so that significant improvement in the performance of IP over WDM can be achieved. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 247–249, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11028
Comments on “On the analysis of a weakly guiding doubly clad dielectric optical fiber with an annular core”
Authors: Marcou J. , Février S.
Published: June 2003

A discussion of the dispersion relation of the modes guided by an annular core fiber is done in order to prove that the fundamental mode has a zero cutoff. It also gives the inequalities satisfied by the cutoff frequencies of the first lower modes. A relation is established between the propagation constants of two modes with the same radial order but different azimuthal orders. It allows us to precisely set the conditions for these constants to be almost similar. Numerical results are shown to confirm these assertions. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 249–254, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11029
Dynamic shortest paths minimizing travel times and costs
Authors: Ahuja Ravindra K. , Orlin James B. , Pallottino Stefano , Scutellà Maria G.
Published: June 2003

In this paper, we study dynamic shortest path problems that determine a shortest path from a specified source node to every other node in the network where arc travel times change dynamically. We consider two problems: the minimum‐time walk problem and the minimum‐cost walk problem. The minimum‐time walk problem is to find a walk with the minimum travel time. The minimum‐cost walk problem is to find a walk with the minimum weighted sum of the travel time and the excess travel time (over the minimum possible travel time). The minimum‐time walk problem is known to be polynomially solvable for a class of networks called FIFO networks. In this paper, (i) we show that the minimum‐cost walk problem is an NP‐hard problem; (ii) we develop a pseudopolynomial‐time algorithm to solve the minimum‐cost walk problem (for integer travel times); and (iii) we develop a polynomial‐time algorithm for the minimum‐time walk problem arising in road networks with traffic lights. © 2003 Wiley Periodicals, Inc.
A bicriterion approach for routing problems in multimedia networks
Authors: Clímaco João C. N. , Craveirinha José M. F. , Pascoal Marta M. B.
Published: June 2003

Routing problems in communication networks supporting multiple services, namely, multimedia applications, involve the selection of paths satisfying multiple constraints (of a technical nature) and seeking simultaneously to “optimize” the associated metrics. Although traditional models in this area are single‐objective, in many situations, it is important to consider different, eventually conflicting, objectives. In this paper, we consider a bicriterion model dedicated to calculating nondominated paths for specific traffic flows (associated with video services) in multiservice high‐speed networks. The mathematical formulation of the problem and the bicriterion algorithmic approach developed for its resolution are presented together with computational tests regarding an application to video‐traffic routing in a high‐speed network. The algorithmic approach is an adaptation of recent work by Ernesto Martins and his collaborators, namely, the MPS algorithm. © 2003 Wiley Periodicals, Inc.
Upper bounds for single‐source uncapacitated concave minimum‐cost network flow problems
Authors: Fontes Dalila B. M. M. , Hadjiconstantinou Eleni , Christofides Nicos
Published: June 2003

In this paper, we describe a heuristic algorithm based on local search for the Single‐Source Uncapacitated (SSU) concave Minimum‐Cost Network Flow Problem (MCNFP). We present a new technique for creating different and informed initial solutions to restart the local search, thereby improving the quality of the resulting feasible solutions (upper bounds). Computational results on different classes of test problems indicate the effectiveness of the proposed method in generating basic feasible solutions for the SSU concave MCNFP very near to a global optimum. A maximum upper bound percentage error of 0.07% is reported for all problem instances for which an optimal solution has been found by a branch‐and‐bound method. © 2003 Wiley Periodicals, Inc.
The determination of the path with minimum‐cost norm value
Authors: Paixão José M. P. , de Queirós Vieira Martins Ernesto , Rosa Mário S. , Santos José Luis E.
Published: June 2003

The multiobjective shortest path problem (MSPP) consists of finding the best nondominated path linking two specified nodes in a network where k > 1 different criteria are considered for the arc costs. Solving the MSPP implies determining all the nondominated paths; there may be many such paths, making the selection process a very hard task to accomplish. A traditional way of dealing with such a difficulty is using a utility function where the parameters are aggregated with different weights. In this work, an alternative utility function based on the norm value associated with each path is considered. Two algorithms for solving the minimum‐cost norm path problem are then proposed and some computational results are presented. © 2003 Wiley Periodicals, Inc.
Incentives for pollution abatement: Regulation, regulatory threats, and non‐governmental pressures
Authors: Harrison Kathryn , Antweiler Werner
Published: June 2003

In the last decade, voluntary efforts by firms to reduce their environmental impacts have received increasing
attention from both policymakers and scholars. This article discusses polluters' incentives to reduce their
releases. In particular, using data from Canada's National Pollutant Release Inventory, it examines the
impacts of conventional regulation, threats of regulation, and non‐governmental pressures facilitated by
public dissemination of information about pollutant releases. The vast majority of reductions reported to the
inventory to date were found not to be voluntary, as has often been assumed, but are, rather, the result of
direct regulation of a relatively small number of polluters. Strong effects of federal regulation were found
among other sources, as well, with much weaker responses to the mere threat of regulation. However, of concern
are the growth of less visible waste streams—such as land disposal and underground injection—as well
as transfers of wastes to other communities. Finally, evidence is reported that some waste streams are
increasing in toxicity, an effect that may outweigh the benefits of reductions in releases. © 2003 by the
Association for Public Policy Analysis and Management.
Community environmental policing: Assessing new strategies of public participation in environmental regulation
Authors: O'Rourke Dara , Macey Gregg P.
Published: June 2003

This paper evaluates a new form of public participation in environmental monitoring and regulation advanced
through local “bucket brigades,” which allow community members to sample air emissions near
industrial facilities. These brigades represent a new form of community environmental policing, in which
residents participate in collecting, analyzing, and deploying environmental information, and more importantly,
in an array of public policy dialogues. Use of this sampling technology has had marked effects on local
residents' perceptions and participation in emergency response and citizens'
right‐to‐know. However, when viewed through the lens of the more developed literature on community
policing, the bucket brigades are currently limited in their ability to encourage
“co‐production” of environmental protection between citizens and the state. Means are
examined to strengthen the bucket brigades and to more broadly support community participation in environmental
regulation. © 2003 by the Association for Public Policy Analysis and Management.
Public transit and the spatial distribution of minority employment: Evidence from a natural experiment
Authors: Holzer Harry J. , Quigley John M. , Raphael Steven
Published: June 2003

A recent expansion of the San Francisco Bay Area's heavy rail system represents an exogenous change in
the accessibility of inner‐city minority communities to a concentrated suburban employment center. We
evaluate this natural experiment by conducting a two‐wave longitudinal survey of firms, with the first
wave of interviews conducted immediately before the opening of service, and the second wave approximately a year
later. Within‐firm changes in the propensity to hire minority workers for firms near the station were
compared with those located farther away. Also estimated was the effect of employer distance to the new stations
on changes in propensity to hire minorities. Results indicate a sizable increase in the hiring of Latinos near
the new stations, but little evidence of an effect on black hiring rates. © 2003 by the Association for
Public Policy Analysis and Management.
Do child care regulations affect the child care and labor markets?
Authors: Blau David M.
Published: June 2003

The effect of child care regulations on outcomes in the child care market and the labor market for mothers of
young children is examined. The analysis uses a time series of cross sections and examines the robustness of
previous cross‐section findings to controls for state‐level heterogeneity. Child care regulations
as a group have statistically significant effects on most outcomes, with or without state fixed effects.
However, regulations do not vary enough within state over time to allow precise identification of most
individual regulation effects. The great majority of estimated regulation effects in all specifications are
small and insignificantly different from 0. Some of the estimated effects seem reasonable in sign and magnitude,
but others are clearly implausible. © 2003 by the Association for Public Policy Analysis and
Management.
Shape and diffusion of the monomer‐controlled copolymerization of ethylene and α‐olefins over Cp2ZrCl2 confined in the nanospace of the supercage of NaY
Authors: Ko Young Soo , Woo Seong Ihl
Published: June 2003

Cp2ZrCl2 confined inside the supercage of NaY zeolites [NaY/methylaluminoxane (MAO)/Cp2ZrCl2] exhibited the shape and diffusion of a monomer‐controlled copolymerization mechanism that strongly depended on the molecular structure of the monomer and its size. For the ethylene–propylene copolymerization, NaY/MAO/Cp2ZrCl2 showed the effect of the comonomer on the increase in the polymerization rate in the presence of propylene, whereas the ethylene/1‐hexene copolymerization showed little comonomer effect, and the ethylene/1‐octene copolymerization instead showed a comonomer depression effect on the polymerization rate. Isobutylene, having a larger kinetic diameter, had little influence on the copolymerization behaviors with NaY/MAO/Cp2ZrCl2 for the ethylene–isobutylene copolymerization, which showed evidence of the shape and diffusion of a monomer‐controlled mechanism. The content of the comonomer in the copolymer chain prepared with NaY/MAO/Cp2ZrCl2 decreased by about one‐half in comparison with that of Cp2ZrCl2. A differential scanning calorimetry study on the melting endotherms after the successive annealing of the copolymers showed that the copolymers of NaY/MAO/Cp2ZrCl2 had narrow comonomer distributions, whereas those of homogeneous Cp2ZrCl2 were broad. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2171–2179, 2003
Synthesis and copolymerization of new phosphorus‐containing acrylates
Authors: Avci Duygu , Albayrak Aylin Ziylan
Published: June 2003

Two phosphorus‐containing acrylate monomers were synthesized from the reaction of ethyl α‐chloromethyl acrylate and t‐butyl α‐bromomethyl acrylate with triethyl phosphite. The selective hydrolysis of the ethyl ester monomer with trimethylsilyl bromide (TMSBr) gave a phosphonic acid monomer. The attempted bulk polymerizations of the monomers at 57–60 °C with 2,2′‐azobisisobutyronitrile (AIBN) were unsuccessful; however, the monomers were copolymerized with methyl methacrylate (MMA) in bulk at 60 °C with AIBN. The resulting copolymers produced chars on burning, showing potential as flame‐retardant materials. Additionally, α‐(chloromethyl)acryloyl chloride (CMAC) was reacted with diethyl (hydroxymethyl)phosphonate to obtain a new monomer with identical ester and ether moieties. This monomer was hydrolyzed with TMSBr, homopolymerized, and copolymerized with MMA. The thermal stabilities of the copolymers increased with increasing amounts of the phosphonate monomer in the copolymers. A new route to highly reactive phosphorus‐containing acrylate monomers was developed. A new derivative of CMAC with mixed ester and ether groups was synthesized by substitution, first with diethyl (hydroxymethyl)phosphonate and then with sodium acetate. This monomer showed the highest reactivity and gave a crosslinked polymer. The incorporation of an ester group increased the rate of polymerization. The relative reactivities of the synthesized monomers in photopolymerizations were determined and compared with those of the other phosphorous‐containing acrylate monomers. Changing the monomer structure allowed control of the polymerization reactivity so that new phosphorus‐containing polymers with desirable properties could be obtained. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2207–2217, 2003
Coarse‐grained models and collective phenomena in membranes: Computer simulation of membrane fusion
Authors: Müller M. , Katsov K. , Schick M.
Published: June 2003

We discuss the role coarse‐grained models play in investigating collective phenomena in bilayer membranes and place them in the context of alternative approaches. By reducing the degrees of freedom and applying simple effective potentials, coarse‐grained models can address the large time scales and length scales of collective phenomena in membranes. Although the mapping from a coarse‐grained model onto chemically realistic models is a challenge, such models provide a direct view on the phenomena that occur on the length scales of a few tens of nanometers. Their relevance is exemplified by the study of fusion of model membranes. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1441–1450, 2003
Utilization of prompt‐γ neutron activation analysis in the evaluation of Nafion membranes
Authors: Young Sandra K. , Trevino Samuel F. , Tan Nora C. Beck , Paul Rick L.
Published: June 2003

Researchers have performed evaluations on Nafion membranes for many years. An important aspect of the membranes is their chemical composition and uniformity. One technique that could provide accurate and fast quantitative measurements of the chemical composition and water within the membranes is prompt‐γ neutron activation analysis (PGAA). In this work, PGAA was applied to the chemical characterization of Nafion membranes in various forms. The evaluation confirmed the necessity of pretreatment of the membranes for the elimination of contamination. A series of counterion‐exchanged membranes were examined so that we could determine the degree of conversion achieved under different conditions and residual water levels. The results indicated that the type of counterion was an important factor determining conversion levels, that partial conversion could be achieved, and that counterion displacement could be forced to occur in certain environments. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1485–1492, 2003