bluuebunny/crossref_metadata_2025 huggingface dataset:
Reduced microwave loss in trenched superconducting coplanar waveguides
Authors: Vissers Michael R. , Kline Jeffrey S. , Gao Jiansong , Wisbey David S. , Pappas David P.
Published: February 2012

Reducing the contribution of all sources of microwave loss is important for increasing coherence times in superconducting qubits. In this paper we investigate reducing the loss by systematically removing Si substrate material from the gap region in titanium nitride coplanar waveguides fabricated on intrinsic Si substrates. By exploiting the radial dependence of the etch rate in a parallel plate reactive ion etcher, otherwise identical coplanar waveguides with only the Si gaps etched to varying depth, i.e., trenched, were created in a single TiN film within a single processing step. Measurements at these multiple depths permit the study of the loss reduction in isolation to the unintentional effects caused by any single processing step. When comparing the loss from all trench depths we found that the high power loss was similar, but in the single photon limit the loss was reduced by a factor of two for deeper trenches in agreement with predictions from finite element analysis.
Solution doping of organic semiconductors using air-stable n-dopants
Authors: Qi Yabing , Mohapatra Swagat K. , Bok Kim Sang , Barlow Stephen , Marder Seth R. , Kahn Antoine
Published: February 2012

Solution-based n-doping of the polymer poly{[N,N′-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-bithiophene)} [P(NDI2OD-T2)] and the small molecule 6,13-bis(tri(isopropyl)silylethynyl)pentacene (TIPS-pentacene) is realized with the air-stable dimers of rhodocene, [RhCp2]2, and ruthenium(pentamethylcyclopentdienyl)(1,3,5-triethylbenzene), [Cp*Ru(TEB)]2. Fermi level shifts, measured by direct and inverse photoemission spectroscopy, and orders of magnitude increase in current density and film conductivity point to strong n-doping in both materials. The strong reducing power of these air-stable dopants is demonstrated through the n-doping of TIPS-pentacene, a material with low electron affinity (3.0 eV). Doping-induced reduction of the hopping transport activation energy indicates that the increase in film conductivity is due in part to the filling of deep gap states by carriers released by the dopants.
Dynamic denitrosylation via
S
-nitrosoglutathione reductase regulates cardiovascular function
Authors: Beigi Farideh , Gonzalez Daniel R. , Minhas Khalid M. , Sun Qi-An , Foster Matthew W. , Khan Shakil A. , Treuer Adriana V. , Dulce Raul A. , Harrison Robert W. , Saraiva Roberto M. , Premer Courtney , Schulman Ivonne Hernandez , Stamler Jonathan S. , Hare Joshua M.
Published: February 2012

Although protein
S
-nitrosylation is increasingly recognized as mediating nitric oxide (NO) signaling, roles for protein denitrosylation in physiology remain unknown. Here, we show that
S
-nitrosoglutathione reductase (GSNOR), an enzyme that governs levels of
S
-nitrosylation by promoting protein denitrosylation, regulates both peripheral vascular tone and β-adrenergic agonist-stimulated cardiac contractility, previously ascribed exclusively to NO/cGMP. GSNOR-deficient mice exhibited reduced peripheral vascular tone and depressed β-adrenergic inotropic responses that were associated with impaired β-agonist–induced denitrosylation of cardiac ryanodine receptor 2 (RyR2), resulting in calcium leak. These results indicate that systemic hemodynamic responses (vascular tone and cardiac contractility), both under basal conditions and after adrenergic activation, are regulated through concerted actions of NO synthase/GSNOR and that aberrant denitrosylation impairs cardiovascular function. Our findings support the notion that dynamic
S
-nitrosylation/denitrosylation reactions are essential in cardiovascular regulation.
A Bayesian approach to targeted experiment design
Authors: Vanlier J. , Tiemann C. A. , Hilbers P. A. J. , van Riel N. A. W.
Published: February 2012

Motivation: Systems biology employs mathematical modelling to further our understanding of biochemical pathways. Since the amount of experimental data on which the models are parameterized is often limited, these models exhibit large uncertainty in both parameters and predictions. Statistical methods can be used to select experiments that will reduce such uncertainty in an optimal manner. However, existing methods for optimal experiment design (OED) rely on assumptions that are inappropriate when data are scarce considering model complexity.

Results: We have developed a novel method to perform OED for models that cope with large parameter uncertainty. We employ a Bayesian approach involving importance sampling of the posterior predictive distribution to predict the efficacy of a new measurement at reducing the uncertainty of a selected prediction. We demonstrate the method by applying it to a case where we show that specific combinations of experiments result in more precise predictions.

Availability and implementation: Source code is available at: http://bmi.bmt.tue.nl/sysbio/software/pua.html

Contact:  j.vanlier@tue.nl; N.A.W.v.Riel@tue.nl

Supplementary information:  Supplementary data are available at Bioinformatics online.
Homelessness and access to the informational mainstream
Authors: Muggleton Thomas H. , Ruthven Ian
Published: February 2012

Purpose

This paper aims to explore how homelessness affects access to information serving higher‐level needs such as identity formation and social interaction.

Design/methodology/approach

A multi‐disciplinary literature review informed the design of 18 semi‐structured interviews as well as their subsequent analysis. The interview data were intended to be qualitative and exploratory since they addressed a perceived gap in the information and library science literature.

Findings

Findings present the ways in which interviewees managed to access information and the way such information helps socialisation and well‐being.

Research limitations/implications

The study focused on individuals who were potentially more confident and resourceful. The study is also limited to Glasgow which has relatively good provision for the homeless. Further research in a different locale and among less confident individuals would be necessary to corroborate findings in this regard.

Practical implications

The findings confirmed a fundamental research assumption that homeless individuals would pursue higher‐level needs alongside more basic physiological needs. This has practical implications for public libraries' service provision to homeless populations, and also suggests there is greater room for collaboration between libraries and homeless service agencies.

Originality/value

The paper addresses a gap in the literature concerning homelessness and higher‐level needs. This has implications for the provision of information and services within both public libraries and organisations serving the homeless. Findings also challenge widespread assumptions regarding the “otherness” or distinctiveness of people who are homeless.
Identification of lubricant contamination by biodiesel using vibration analysis and neural network
Authors: Carlos Gonçalves Aparecido , Rodrigues Padovese Linilson
Published: February 2012

Purpose

The purpose of this paper is to provide information on lubricant contamination by biodiesel using vibration and neural network.

Design/methodology/approach

The possible contamination of lubricants is verified by analyzing the vibration and neural network of a bench test under determinated conditions.

Findings

Results have shown that classical signal analysis methods could not reveal any correlation between the signal and the presence of contamination, or contamination grade. On other hand, the use of probabilistic neural network (PNN) was very successful in the identification and classification of contamination and its grade.

Research limitations/implications

This study was done for some specific kinds of biodiesel. Other types of biodiesel could be analyzed.

Practical implications

Contamination information is presented in the vibration signal, even if it is not evident by classical vibration analysis. In addition, the use of PNN gives a relatively simple and easy‐to‐use detection tool with good confidence. The training process is fast, and allows implementation of an adaptive training algorithm.

Originality/value

This research could be extended to an internal combustion engine in order to verify a possible contamination by biodiesel.
Characteristics of high performing managers in The Netherlands
Authors: de Waal André A. , van der Heijden Béatrice I.J.M. , Selvarajah Christopher , Meyer Denny
Published: February 2012

Purpose

Despite the abundance of literature on management it seems that the quality of management has not improved enough to prevent scandals which have occurred in recent years. It could be that either the results of these studies have not been put to use in practice or that the results were biased because of the rather one‐sided focus on US managers in much of the leadership literature. As national cultures signal different determinants of high performance, there is a need for leadership research into the effectiveness characteristics of managers in non‐US countries. This article aims to develop an empirically validated profile of high performing managers in The Netherlands using a leadership framework developed in Asia.

Design/methodology/approach

Based on a sample of 808 Dutch managers and using the cross‐cultural framework of Excellent Leadership by Selvarajah et al., the profile of an excellent Dutch manager was derived.

Findings

The paper reveals that this profile can be described by a four‐dimensional factor structure consisting of managerial behaviours, environmental influences, personal qualities and organisational demands.

Research limitations/implications

The main limitation of the research is that the findings are based on reports from a single source; namely managers' perceptions. Hence, common‐method effects may have inflated the correlations.

Practical implications

The results of the research can serve as guidelines for developing an empirically validated profile of high performance managers (HPMs) in other Western countries. They also have practical implications in that organizations can use the HPM profile to tailor their management development programs, evaluation and coaching programs, and recruiting processes in order to improve the quality of their managers.

Originality/value

To the best of the authors' knowledge, this is the first time a leadership framework developed in the Eastern world has been applied on Western managers, making this research one of the first of its kind. This is important because, as stated before, there is a strong need for research which extends the theoretical and practical basis of leadership theories from a solely Western focus to a more balanced Western‐Eastern focus. The results from this type of research can provide guidance for improving quality of management worldwide.
Factor analysis of global trends in twenty‐first century leadership
Authors: Perrin Craig , Perrin Paul B. , Blauth Chris , Apthorp East , Duffy Ryan D. , Bonterre Michelle , Daniels Sharon
Published: February 2012

Purpose

The purpose of this study is to examine whether the nature of leadership in the early years of the twenty‐first century as conceptualized in the research literature is valid among real organizational leaders across four global regions.

Design/methodology/approach

A literature review of recent scholarly articles suggested that today's leadership best practices can be sorted into six categories, or zones: Reflection, Society, Diversity, Ingenuity, People, and Business. These six zones became topics for focus groups of organizational leaders that tentatively supported the six‐zone structure and provided qualitative data used to create a 42‐item measure, the AchieveGlobal Leadership Scale (AGLS). The AGLS was then employed to examine the degree to which 899 leaders in Asia, Europe, Latin America, and the USA felt that each zone was important in meeting their organizational challenges.

Findings

The data from the 42 items were analyzed using a confirmatory factor analysis, which suggested that the six zones all triangulated on and comprised the larger construct, Leadership in the twenty‐first century. Regional differences emerged in the importance that leaders attributed to the zones, in the degree to which leaders effectively demonstrated the zones, and in the order in which leaders ranked their organizations' top business challenges.

Originality/value

The six‐zone model of leadership and its differences by geographic region hold potential to help leaders examine and improve their own leadership abilities.
Validation of the adaptive reuse potential (ARP) model using iconCUR
Authors: Langston Craig
Published: February 2012

Purpose

This paper aims to focus on the adaptive reuse of existing buildings that have become obsolete, an important strategy for sustainable development and a pertinent response to excessive resource usage resulting from typical destruction and redevelopment.

Design/methodology/approach

This paper looks at the validity of earlier work to model adaptive reuse potential (ARP) using a new multiple criteria decision analysis tool called iconCUR. Based on a review of 12 case studies, the paper determines the extent of agreement between ARP and iconCUR evaluations that both claim to be useful in making decisions about reuse.

Findings

The results show a high correlation between these approaches, whether based on raw scores or on relative ranking, and match expert opinion concerning appropriate actions. This work represents the culmination of a three‐year study into the strategic assessment of building adaptive reuse opportunities.

Originality/value

The paper provides confidence in the modelling of future interventions to revitalise existing built assets using a triple bottom line perspective.
Feasibility study of a simple IAQ index for assessing air‐conditioned offices
Authors: Hui P.S. , Mui K.W. , Wong L.T.
Published: February 2012

Purpose

It is costly to sample all air pollutants of a general community for continuous indoor air quality (IAQ) assessments. To optimize the resources for IAQ baseline monitoring for general facilities management, this study aims to investigate the feasibility of using a simple IAQ index as a screening parameter of a screening test to identify an asymptomatic air‐conditioned office with probable unsatisfactory IAQ.

Design/methodology/approach

The IAQ index is determined from the fractional dose of some representative common indoor air pollutants of unsatisfactory IAQ, either by taking equal importance of the pollutants as a weighting factor or weighted by the regional failure rates with respect to the corresponding air pollutants. Specifically, a database of regional IAQ assessment results of 422 air‐conditioned offices was employed to justify the selected screening levels for the IAQ index.

Findings

The proposed IAQ index of a screening assessment was used for verifying, respectively, 58 and seven air‐conditioned offices of Hong Kong with satisfactory and unsatisfactory IAQ. The results showed that 57 satisfactory offices and two unsatisfactory offices were correctly identified by the unweighted and weighted IAQ indices respectively. Evaluation of the proposed index in further IAQ improvements of some offices showed that it would be a practical tool for preliminary IAQ screening assessment.

Research limitations/implications

The screening test itself could not identify all the IAQ problems but could identify the office groups with higher risk of unsatisfactory IAQ with reduced effort.

Practical implications

The study shows the usefulness of the proposed IAQ index to identify the unrecognized IAQ problems for air‐conditioned office environments. It could be adopted as a routine screening measure in facility management of which a wide‐ranging set of IAQ measurement is undesired.

Originality/value

This study presents a useful reference for policymakers, building owners and professionals for indoor environmental assessments.
Buyer‐supplier collaboration: the aim of FM procurement?
Authors: Plane Caroline V. , Green Andrew N.
Published: February 2012

Purpose

The purpose of this study is to explore the causal link between procurement route and ongoing buyer‐supplier relationship.

Design/methodology/approach

The research draws on literature in the areas of: facilities management (FM) outsourcing; purchasing and supply chain strategy; and collaborative business relationship management. The research methodology is qualitative, and comprised semi‐structured interviews with buyers and suppliers of FM services.

Findings

Findings suggest that in general clients are seeking more collaborative relationships and this may determine a more relational procurement process. Some organisations appear more practiced than others in defining the level of collaboration and business benefits sought. Results support the view that a relational procurement process provides greater clarity of service requirements and facilitates cultural alignment between the buyer and supplier. However, additional time, effort, and cost are incurred, and concerns arise regarding the maturity of the supplier‐market and the sincerity of client intentions to collaborate.

Practical implications

A major practical implication is that facilities managers should recognise the importance of determining relationship objectives and the benefits sought within the context of FM procurement activity and select a purchasing route which supports the achievement of those objectives.

Originality/value

Originality exists in the qualitative approach used to inquire into the causality between relationships and procurement routes. The study offers potential value to both buyers and suppliers of FM services through describing the attributes of a successful collaborative relationship and how they link to a given procurement process, and identifying the potential risks and rewards involved.
Explaining the variations in the pedestrian flow values of shopping centres
Authors: Lam Bonnie Y.M. , Chau K.W.
Published: February 2012

Purpose

The purpose of this paper is to identify and analyse the crucial variables of pedestrian flow value of the shopping centres in Hong Kong.

Design/methodology/approach

The study identifies the key determinants of pedestrian flow value (PFV) which is measured by net rental income per floor area per pedestrian flow. Based on the rental and pedestrian flow survey data of 146 shopping centres along the subway (Mass Transit Railway) stations in Hong Kong, the authors have estimated the marginal effects of these determinants on the PFV. The research explains different variations' impacts of pedestrian flow on the rental value of the shopping centres in Hong Kong.

Findings

It is found that shopping centres owned by the same owners tend to achieve a lower PFV, which suggests that owners of multiple shopping malls may adopt a uniform pedestrian flow management strategy that may not be ideal for each individual mall.

Research limitations/implications

This study focuses on the shopping centres that are located along the railway stations. Researchers are encouraged to test the shopping centres that are less affected by the railway stations.

Practical implications

It is useful for shopping centre owners and operators to determine the optimal strategy for managing pedestrian flow in their shopping centres.

Originality/value

The relationship between pedestrian flow and the shopping centre value is coined in the research as pedestrian flow value (PFV) which is to calculate the pedestrian flow effectiveness measured by net rental income per floor area per pedestrian flow.
Nonlinear analysis of RC shell structures using multilevel modelling techniques
Authors: Gopinath Smitha , Iyer Nagesh , Rajasankar J. , D'Souza Sandra
Published: February 2012

Purpose

The purpose of this paper is to present integrated methodologies based on multilevel modelling concepts for finite element analysis (FEA) of reinforced concrete (RC) shell structures, with specific reference to account for the nonlinear behaviour of cracked concrete and the other associated features.

Design/methodology/approach

Geometric representation of the shell is enabled through multiple concrete layers. Composite characteristic of concrete is accounted by assigning different material properties to the layers. Steel reinforcement is smeared into selected concrete layers according to its position in the RC shell. The integrated model concurrently accounts for nonlinear effects due to tensile cracking, bond slip and nonlinear stress‐strain relation of concrete in compression. Smeared crack model having crack rotation capability is used to include the influence of tensile cracking of concrete. Propagation and change in direction of crack along thickness of shell with increase in load and deformation are traced using the layered geometry model. Relative movement between reinforcing steel and adjacent concrete is modelled using a compatible bond‐slip model validated earlier by the authors. Nonlinear iterative solution technique with imposed displacement in incremental form is adopted so that structures with local instabilities or strain softening can also be analysed.

Findings

Proposed methodologies are validated by evaluating ultimate strength of two RC shell structures. Nonlinear response of McNeice slab is found to compare well with that of experiment available in literature. Then, a RC cooling tower is analysed for factored wind loads to study its behaviour near ultimate load. Numerical validation demonstrates efficacy and usefullness of the proposed methodologies for nonlinear FEA of RC shell structures.

Originality/value

The present paper integrates critical methodologies used for behaviour modelling of concrete and reinforcement with the physical interaction among them. The study is unique by considering interaction of tensile cracking and bond‐slip which are the main contributors to nonlinearity in the nonlinear response of RC shell structures. Further, industrial application of the proposed modelling strategy is demonstrated by analysing a RC cooling tower shell for its nonlinear response. It is observed that the proposed methodologies in the integrated manner are unique and provide stability in nonlinear analysis of RC shell structures.
A local remeshing procedure to simulate crack propagation in quasi‐brittle materials
Authors: Kuutti Juha , Kolari Kari
Published: February 2012

Purpose

The purpose of this paper is to present a new simplified local remeshing procedure for the study of discrete crack propagation in finite element (FE) mesh. The proposed technique accounts for the generation and propagation of crack‐like failure within an FE‐model. Beside crack propagation, the technique enables the analysis of fragmentation of initially intact continuum. The capability of modelling fragmentation is essential in various structure‐structure interaction analyses such as projectile impact analysis and ice‐structure interaction analysis.

Design/methodology/approach

The procedure combines continuum damage mechanics (CDM), fictitious crack approach and a new local remeshing procedure. In the approach a fictitious crack is replaced by a discrete crack by applying delete‐and‐fill local remeshing. The proposed method is independent of mesh topology unlike the traditional discrete crack approach. The procedure is implemented for 3‐D solid elements in commercial finite element software Abaqus/Explicit using Python scripting. The procedure is completely automated, such that crack initiation and propagation analyses do not require user intervention. A relatively simple constitutive model was implemented strictly for demonstrative purposes.

Findings

Well known examples were simulated to verify the applicability of the method. The simulations revealed the capabilities of the method and reasonable correspondence with reference results was obtained. Material fragmentation was successfully simulated in ice‐structure interaction analysis.

Originality/value

The procedure for modelling discrete crack propagation and fragmentation of initially intact quasi‐brittle materials based on local remeshing has not been presented previously. The procedure is well suited for simulation of fragmentation and is implemented in a commercial FE‐software.
Comprehensive 3‐capacitors model for partial discharge in power cables
Authors: Haghjoo Farhad , Khanahmadloo Esmaeel , Mohammad Shahrtash S.
Published: February 2012

Purpose

The paper proposes and presents a comprehensive and integrated circuit model for investigating the behaviour of partial discharges occurring in voids inside the solid insulations of medium and high voltage cables.

Design/methodology/approach

The model is based on the well‐known three capacitors model, which is remarkably improved to handle physical parameters such as cavity size, position, shape and pressure, environmental parameters such as cable temperature, in addition to operational parameters such as the contributions of the avalanche of free electrons inside the cavity through considering stochastic time delays.

Findings

A complete, flexible and reliable model for partial discharges in voids inside the solid insulation of medium and high voltage cables is presented whose output agrees with experimental reported results.

Research limitations/implications

The proposed model deals only with single voids, and the semiconductor layers in the insulation of cables are not considered.

Practical implications

The model can be used in different physical, environmental and operational conditions in order to investigate the characteristics of partial discharge signals to be used as the bases for partial discharge detection and classification in power cables.

Originality/value

This paper presents a novel comprehensive and integrated circuit model with controlling functions to propose the behaviour of partial discharge occurring in voids inside the solid insulation of power cables. The model provides the contribution of geometrical parameters of the void, and operational conditions such as cable temperature and source frequency in partial discharge analysis.
Experimental and numerical comparison between the output voltages of two novel switched reluctance generators
Authors: Sedigh Toulabi Mohammad , Torkaman Hossein , Afjei Ebrahim
Published: February 2012

Purpose

The purpose of this paper is to propose a combination of two novel switched reluctance generators (SRG) as a suitable prototype to produce electrical energy using natural, renewable and variable speed energy resource. The paper focuses on the voltage generation analysis of two special SRGs.

Design/methodology/approach

To evaluate the proposed configurations, their structures are introduced firstly, and the output voltages of both two generators are analyzed numerically via three dimensional finite element method. After that the obtained results are validated on laboratory set up. Moreover, the main parameters of each one causing the output voltages are studied. The proposed generators have been manufactured within a common physical framework. This framework consists of two magnetically independent stator and rotor sets (layers), where each stator set includes four salient poles, while the rotor comprises of two salient poles with almost equal arc lengths and no windings. The first generator called Field assisted SRG which has a stationary reel, and so the field coil wrapped around it, and it is placed between the two‐stator sets, whereas in the second type named Self excited SRG, there is no field coil.

Findings

Via experimental and numerical analysis, it is substantiated that this interesting combination can help users to produce electrical energy from low speeds to high speeds of performance through employing each of these generators in special case of study and application separately.

Originality/value

This beneficial characteristic of two proposed SRGs can be noticed as a suitable trait in different industries such as aerospace, automobile and production of electrical energy via windmills.
Classification of power quality disturbances using wavelet packet energy and multiclass support vector machine
Authors: Zhang Ming , Li Kaicheng , Hu Yisheng
Published: February 2012

Purpose

The purpose of this paper is to develop a new method for classification of power quality (PQ) disturbances such as the sag, interruption, swell, harmonic, notch, oscillatory transient and impulsive transient.

Design/methodology/approach

A PQ disturbances classification system based on wavelet packet energy and multiclass support vector machines (MSVM) is proposed to discriminate seven types of PQ disturbances. The PQ disturbance signals are first decomposed into components in different subbands using discrete wavelet packet transform (DWPT). Statistical features of the decomposed signals are required to characterize the PQ disturbances. A MSVM classifier follows to classify the PQ disturbances.

Findings

The proposed method could effectively detect information from disturbance waveforms using DWPT and MSVM techniques, which is verified on over 700 samples.

Research limitations/implications

The classification stage of the proposed method does not differentiate the disturbances occurred simultaneously.

Practical implications

The proposed method possesses high recognition rate, so it is suitable for the PQ monitoring system for detection and classification of disturbances.

Originality/value

The paper describes a new and efficient way of classification of PQ disturbances. In this paper, an attempt has been made to extract efficient features of the PQ disturbances using DWPT. It is observed that these features can help correctly classify the PQ disturbances, even under noisy conditions. The MSVM is compared with artificial neural network (ANN) and it is found that the MSVM classifier gives the better result.
A novel self consistent calculation approach for the capacitance‐voltage characteristics of semiconductor quantum wire transistors based on a split‐gate configuration
Authors: Ragi Regiane , da Nobrega Rafael V.T. , Romero Murilo A.
Published: February 2012

Purpose

The purpose of this paper is to develop an efficient numerical algorithm for the self‐consistent solution of Schrodinger and Poisson equations in one‐dimensional systems. The goal is to compute the charge‐control and capacitance‐voltage characteristics of quantum wire transistors.

Design/methodology/approach

The paper presents a numerical formulation employing a non‐uniform finite difference discretization scheme, in which the wavefunctions and electronic energy levels are obtained by solving the Schrödinger equation through the split‐operator method while a relaxation method in the FTCS scheme (“Forward Time Centered Space”) is used to solve the two‐dimensional Poisson equation.

Findings

The numerical model is validated by taking previously published results as a benchmark and then applying them to yield the charge‐control characteristics and the capacitance‐voltage relationship for a split‐gate quantum wire device.

Originality/value

The paper helps to fulfill the need for C‐V models of quantum wire device. To do so, the authors implemented a straightforward calculation method for the two‐dimensional electronic carrier density n(x,y). The formulation reduces the computational procedure to a much simpler problem, similar to the one‐dimensional quantization case, significantly diminishing running time.
A computer‐aided design tool dedicated to isolated DC‐DC converters based on multiobjective optimization using genetic algorithms
Authors: Versèle Christophe , Deblecker Olivier , Lobry Jacques
Published: February 2012

Purpose

This paper presents a computer‐aided design (CAD) tool for the design of isolated dc‐dc converters.

Design/methodology/approach

This tool, developed in Matlab environment, is based on multiobjective optimization (MO) using genetic algorithms. The Elitist Nondominated Sorting Genetic Algorithm is used to perform search and optimization whereas analytical models are used to model the power converters. The design problem requires minimizing the weight, losses and cost of the converter while ensuring the satisfaction of a number of constraints. The optimization variables are, as for them, the operating frequency, the current density, the maximum flux density, the transformer dimensions, the wire diameter, the core material, the conductor material, the converter topology (among Flyback, Forward, Push‐Pull, half‐bridge and full‐bridge topologies), the number of semiconductor devices associated in parallel, the number of cells associated in series or parallel as well as the kinds of input and output connections (serial or parallel) of these cells. Finally, the design of an auxiliary railway power supply is presented and discussed.

Findings

The results show that such tool to design dc‐dc power converters presents several advantages. In particular, it proposes to the designer a set of solutions – instead of a single one – so that he can choose a posteriori which solution best fits the application under consideration. Moreover, interesting solutions not considered a priori can be found with this tool.

Originality/value

To the best of the authors’ knowledge, such a CAD tool including a MO procedure taking several topologies into account has not been suggested so far.
Analysis of some design choices in model based predictive control of flying‐capacitor inverters
Authors: Vyncke Thomas , Thielemans Steven , Jacxsens Michiel , Melkebeek Jan
Published: February 2012

Purpose

Flying‐capacitor multilevel converters (FCC) need a passive or active regulation of the capacitor voltages. Recently the trend is towards active control, often implemented separately from the current control. The advantages of a true multi‐variable control sparked the interest to apply Model Based Predictive Control (MBPC) for FCC. In this paper an objective analysis method to evaluate the effects of several design choices is presented. The effects of the weight factor selection, model simplification, and prediction horizon expansion for MBPC of a 3‐level FCC are analyzed in a systematical way.

Design/methodology/approach

The analysis is mainly based on the mean square error (MSE) of current and capacitor voltage. The results are analysed for different lengths of the prediction horizon and for a wide range of weight factor values. Similarly the effect of a model simplification, neglecting the neutral point voltage, is studied when implementing MBPC for FCCs while considering the computational aspects. Validation of the simulation results is done by experiments on an FPGA‐based setup.

Findings

Including the effect of the neutral point voltage considerably increases the current control quality and a much wider range of good values for the weight factor exists. As this good range is not critically dependent on the current amplitude it is possible to select one weight factor value for all operating points. Furthermore, it is concluded that increasing the prediction horizon increases the computational load without improving the control quality.

Research limitations/implications

The effects of increasing the prediction horizon when including other controlled variables is to be investigated, as well as the robustness to modeling errors. The MSE analysis methodology is very suitable for this further research.

Practical implications

For practitioners of MBPC in power electronics the paper proves that by means of simulations and the MSE one value for weight factor can be chosen for all operating points. The paper clearly shows that a practical implementation is feasible and demonstrates that neglecting the neutral point voltage is not good practice.

Originality/value

The MSE‐based analysis is shown to be a systematical and unbiased methodology to evaluate the effects of design choices. The results from this analysis can be directly applied in practical setups.
A simple unsynchronized two‐end algorithm for faults location and identification in electrical distribution systems
Authors: Riva Sanseverino Eleonora , Campoccia Angelo , Luisa Di Silvestre Maria , Zizzo Gaetano
Published: February 2012

Purpose

The purpose of this paper is to identify a new and simple two‐end algorithm for fault location identification and characterization, in electrical distribution systems.

Design/methodology/approach

The developed diagnostic algorithm is based on a simple model of the network using a lumped parameters representation.

Findings

Test results have proved the approach to be efficient, allowing a precise fault identification and location while not requiring synchronized measures from the two ends.

Research limitations/implications

There is a need for measurement systems at all MV/LV substations.

Practical implications

Applicability with limited investments is not possible where metering systems are not so diffused, although smart grids and DG units require such infrastructures. Moreover, utilities are quite interested in such issues, since the new required quality standards put severe constraints on faults management and clearance.

Originality/value

The paper presents a new and easier diagnostic algorithm for faults diagnosis in distribution systems.
Professional commitment, organizational commitment, and the intention to leave for professional advancement
Authors: Cho Vincent , Huang Xu
Published: February 2012

Purpose

Given the increasing influence and importance of professionals in modern society, this study aims to investigate the influence of organizational commitment and professional commitment on professionals' intention to leave their organizations for professional advancement (ILPA).

Design/methodology/approach

A total of 500 members of a large Hong Kong association of computer specialists were drawn randomly from the membership list. E‐mails were sent directly to those 500 members through a web‐based survey, which is an effective way to collect confidential information and potentially reduced the resistance due to the survey sensitivity. After two follow‐ups via e‐mail, a total of 265 responses were collected with a response rate of 53 percent.

Findings

The study found that organizational affective commitment (OAC) would be more effective for reducing ILPA. For the interactions between different commitment components, there is a substitution effect of professional affective commitment (PAC) and professional continuance component (PCC) toward their impacts on ILPA.

Research limitations/implications

The findings would be explained by the self‐justification process due to cognitive dissonance on the professional's continuance commitment and his/her affective commitment in an organization. Moreover, there would be a complementary relationship between organizational and professional commitment.

Originality/value

This study would answer the question on how to effectively avoid a professional leaving an organization.
The impact of contractors' prequalification on construction project delivery in Nigeria
Authors: Aje Isaac
Published: February 2012

Purpose

Prequalification of contractors is a very important step in construction project procurement under the contract “Due Process” policy in Nigeria. The purpose of this study, therefore, is to investigate the impact of contractors' prequalification on cost, time and quality performance of construction projects.

Design/methodology/approach

Data were collected with the aid of a questionnaire addressed to construction practitioners selected from clients, consultants and contractors' organizations. Also archival data on 77 completed building projects relating to prequalification assessment of contractors and project delivery variables were sourced from consultant quantity surveyors. The data were analysed with the aid of mean score and one‐way analysis of variance (ANOVA).

Findings

The results show that contractors' prequalification has significant impact on time and quality performance of construction projects as evidenced by p‐values of 0.039 and 0.030, respectively.

Practical implications

The findings should provide a valuable reference for clients and consultants during contractors' prequalification and contract award.

Originality/value

The outcome of this paper will assist clients and consultants in the construction industry to carry out objective assessment of contractors' potential performance in relation to project goals prior to contract award.
Careers development in construction firms: application of Sun Tzu'sArt of Warprinciples
Authors: Yean Yng Ling Florence , Yee Lee Sing
Published: February 2012

Purpose

Career development involves how employees manage their career advancement. This study aims to investigate the relevance of Sun Tzu'sArt of Warto career development of construction professionals with the aim of suggesting strategies that may be adopted for career development.

Design/methodology/approach

The data collection technique was in‐depth interviews with 32 subjects who are Singapore‐based construction professionals. The subjects were asked 13 open‐ended questions which were developed based on theArt of War.

Findings

The main findings on the effective career development strategies are: outperforming peers by developing deep job experience and delivering excellent performance; adopting a team member posture before moving on to a team leader stance; handling office politics and conflicts effectively; maintaining flexibility and manoeuvrability in one's career; networking; and acquiring foreknowledge.

Research limitations/implications

The study is qualitative in nature, thus, the actual effectiveness of the recommendations for career development is not known. There may also be some more strategies undisclosed by interviewees as sharing them may cause them to lose their competitive advantage.

Practical implications

The effective strategies for career development are found. Construction professionals may adopt some military strategies that may help them in their career development.

Social implications

The relevance of military strategies to career development in construction firms suggests that career progression is akin to war, where winning is important and strategizing to win is necessary.

Originality/value

In this paper military strategies are mapped onto career development, and relevant career advancement strategies are identified.
Collaborative innovation as the new imperative – design thinking, value co‐creation and the power of “pull”
Authors: Leavy Brian
Published: February 2012

Purpose

This “Masterclass” for corporate leaders aims to explain how to integrate three revolutionary approaches to business innovation to stimulate and propel the creativity that remains latent in and around most organizations.

Design/methodology/approach

Veteran “Masterclass” author Brian Leavy believes that collaborative innovation is the new corporate imperative and explains how three sets of revolutionary thinking and practices – design thinking, value co‐creation and the power of “pull” – can create new opportunities for businesses.

Findings

The paper reveals three key lessons: within the world of business, the design perspective is now being applied to a much wider range of challenges beyond the traditional concerns of product aesthetics and ease‐of‐use, including the search for innovative strategies, business models and organizational structures and processes; the core principle of co‐creation is ‘engaging people to create valuable experiences together while enhancing network economics; and organizations need to learn how to “pull” together, and mobilize as needed, the resources to meet the demands of more engaged consumers, responsively and flexibly as they unfold.

Practical implications

Instead of thinking about “what to build,” prototyping is about “building in order to think,” and the prototyping process itself “creates the opportunity to discover new and better ideas at minimal cost.”

Originality/value

This “Masterclass” offers leaders a lesson on how three revolutionary ideas about business innovation complement each other.
Applying open innovation where your company needs it most
Authors: Muller Amy , Hutchins Nate , Cardoso Pinto Miguel
Published: February 2012

Purpose

While the open innovation concept proposed by Henry Chesbrough a decade ago has had some striking successes, the myriad options for engaging external partners can be daunting, so leaders need a guide for getting started that matches the needs of their firm. This paper aims to address this issue.

Design/methodology/approach

The paper identifies that innovation processes involve three stages during which the business model elements are conceived and elaborated: idea‐generation, idea‐development, and commercialization. The question for leaders is: “In which of the three stages could your growth efforts benefit from an infusion of external ideas and expertise?”

Findings

The open‐innovation approach does not require a company to replace all its current research and development (R&D) efforts. But it does change the primary question leaders should be asking to “How can my company create significantly more value by leveraging external partners to bring many more innovations to market?”

Practical implications

The article shows executives how they can systematically assess an innovation process, understand where new venture business models are weakest, and select the points at which open innovation could add some needed spark.

Originality/value

The article leads executives through two‐step process for introducing a customized open innovation program: step one, assess where your company's innovation process would benefit from external input by using five key questions; and step two, learn how to manage external relationships.
Graphical profiling of team working through participatory research
Authors: Rolfsen Monica , Ingvaldsen Jonas , Hatling Morten
Published: February 2012

Purpose

Companies desire to improve their team organization by learning from other companies in their sector and adopting “best practice”. Researchers and consultants, who are called on to facilitate these learning processes, are confronted with the real world ambiguity and multiple meanings of “team” and “team organization”. A shared understanding of team organization is a precondition for learning and knowledge transfer between companies. This paper seeks to ask how this common understanding can be constructed.

Design/methodology/approach

The paper uses participatory research and a literature review. Based on a research project involving Norwegian manufacturing companies, the paper presents and discusses a participatory process, in which a graphical profiling tool was developed and applied in order to make sense of different forms of team organization.

Findings

The paper finds that companies were actively involved in deciding what the relevant dimensions of team working were. In reflection seminars, systematical comparison between companies dissolved conceptual ambiguity and supported reflection.

Research limitations/implications

The paper reports experiences with the mapping tool from two companies. Both are characterized by cooperative industrial relations, and openness to researchers. More research should be done in order to investigate the general workability of the process proposed here.

Practical implications

The proposed process for constructing and using a mapping tool are relevant for consultants and researchers, who aim to facilitate learning in a multiple company context. In particular, it is relevant for dealing with popular, but unclear concepts such as “team” and “team working”. To be workable, the process should take care to involve relevant stakeholders and the profiling should avoid technical language.

Social implications

Through a participatory approach, all participants in an organization can take part in a dialogue on team working. By introducing a common language, power distances may be reduced.

Originality/value

The general idea of using graphical profiling to support reflection is not original. The contribution is presenting and discussing a concrete participatory process for how graphical profiling can be made relevant and useful.