bluuebunny/crossref_metadata_2025 huggingface dataset:
Hospital operations and length of stay performance
Authors: McDermott Christopher , Stock Gregory N.
Published: August 2007

Purpose

As hospital costs continue to rise, increasing attention is being paid to the way these organizations are and should be managed. This attention typically comes in the form of focus on costs of services, quality (often measured through mortality rates) and length of stay. Hospital management has a broad array of choices at their disposal to address these challenges. As service operations, hospitals present a significant opportunity to apply the many tools and techniques from the field of operations strategy to this important industry. The objective of this paper is to use the operations strategy framework to assess the relationship between a set of operational elements and hospital performance in terms of average length of stay (ALOS), so that hospital managers improve the effectiveness and efficiency of patient care of their hospitals.

Design/methodology/approach

Using the structural and infrastructural operations strategy framework, this study examines the relationship between several strategic variables and hospital performance. To analyze these relationships the paper employs data from the population of hospitals in New York State. The performance measure is the ALOS for patients, adjusted for the mix and severity of cases in each hospital.

Findings

The paper finds that a direct relationship exists between the dependent variable and location, capacity, and teaching status, and failed to find a direct relationship for capital expenditures, salary, and staffing levels. However, the paper did find significant interaction effects between capital expenses and both salary and staffing levels.

Practical implications

There appear to be trade‐offs between capital expenditures and workforce decisions that have significant implications in light of current and expected hospital staffing shortages. The findings indicate that reductions in staff may not be perfectly replaced by corresponding increases in capital expenditures.

Originality/value

This paper further expands the body of research that addresses the important challenges hospitals face from an operations management perspective.
Exchange rate volatility and trade flows: a review article
Authors: Bahmani‐Oskooee Mohsen , Hegerty Scott W.
Published: August 2007

Purpose

Since the last review article by McKenzie, the literature has experienced a surge in the number of empirical articles. These new contributions, coupled with those that were overlooked by McKenzie, set the stage for this review. Many of the recent studies have been empirical in nature and these deserve specific attention. Thus, this paper aims to survey and review all of the studies by paying attention to the attributes outlined in the text.

Design/methodology/approach

This paper examines the vast empirical literature, up to 2005, to assess the main trends in modeling and estimating these trade flows at the aggregate, bilateral, and sectoral levels.

Findings

The increase in exchange‐rate volatility since 1973 has had indeterminate effects on international export and import flows. Although it can be assumed that an increase in risk may lead to a reduction in economic activity, the theoretical literature provides justifications for positive or insignificant effects as well. Similar results have been found in empirical tests. While modeling techniques have evolved over time to incorporate new developments in econometric analysis, no single measure of exchange‐rate volatility has dominated the literature.

Originality/value

An argument put forward by the opponents of the floating exchange rates is that such rates introduce uncertainty into the foreign exchange market, which could deter trade flows. However, a theoretical argument is put forward by some to show that uncertainty could also boost trade flows if traders increase their trade volume to offset any decrease in future revenue due to exchange rate volatility. The empirical literature reviewed in this paper supports both views.
Specifying the effect of location in multivariate valuation models for residential properties
Authors: McCluskey William J. , Borst Richard A.
Published: August 2007

Purpose

The purpose of this research is to explore from a mass appraisal perspective how the effects of location are reflected within valuation models. The paper sets out to detail the various techniques and the efficacy of their application.

Design/methodology/approach

The approach adopted is analytical and based upon the development of locational attributes. An extensive literature base is synthesized with methods being evaluated in their application to mass appraisal.

Findings

This research has identified that the three main groups interested in residential property valuation, namely, academia, industry and commerce have to a certain extent been unfamiliar with the research developments occurring in the other groups. The impact of this is important, given the need for integration and collaboration in terms of future model development.

Research limitations/implications

The research underpinning this paper will provide a solid basis for further research into this area. The importance of measuring the effect that location has on value is of major significance in the determination of objective estimates of property value.

Practical implications

Those within the assessment community could be described as pragmatists working in a situation that requires feasible and suitable solutions to the problem of measuring location value. It is our contention that the third generation techniques of spatially varying parameter models and spatial autocorrelation models will require greater industry verification before their use becomes more widely accepted.

Originality/value

This paper provides a detailed analysis of methodologies used to reflect the value of location over the last 50 years. The debate is taken forward by describing what will be the contribution to the development of the next generation of location‐specific modeling techniques.
Measuring the impact of flooding on UK house prices
Authors: Lamond Jessica , Proverbs David , Antwi Adarkwah
Published: August 2007

Purpose

The purpose of this research is to show how the measurement of the effect of flooding on house value can be invaluable information for professional valuers and homeowners alike. In the UK, even for an event as devastating as the autumn 2000 flood, the number of properties affected in any one town is small and so robust estimation is problematic and methodology applied elsewhere needs modification. A new framework for analysing the effect of flooding on house value in the UK is presented.

Design/methodology/approach

Data issues play a crucial role in determining the methodology employed in any analysis. A repeat sales methodology is proposed which allows for the tracking of effects through time. The analysis can be extended to multiple sites via a block design thereby increasing the sample size.

Findings

Empirical analysis of one case study site demonstrates the inherent small sample problem and yet reveals patterns that fall in line with expected outcomes in many respects.

Research limitations/implications

The case study results are illustrative only. A programme of further analysis is planned which includes comparison of the new framework with more traditional approaches.

Originality/value

A novel methodology is developed tracking the temporal variability in flood effect. The minimisation of data requirements inherent in the model allows for transfer to multiple sites and easy updating of the analysis.
The disposal of public sector sites by “development competition”
Authors: Fisher Peter , Robson Simon , Todd Suzanne
Published: August 2007

Purpose

The purpose of this research is to investigate development competitions in England in order to uncover any shortcomings and point to improvements. A “development competition” is a sale by tender of publicly‐owned land with development potential where bidders also submit designs.

Design/methodology/approach

First, an interview survey of local authorities in north‐east England; second an interview survey with developers in north‐east England; third a questionnaire survey of local authority estates officers and fourth an interview survey with London based property consultants.

Findings

Despite their theoretical attractions, some competitions have problems. Conflict exists between professions and agencies. Development competitions encounter difficulties between developer appointment and construction which may lead to delay or the developer pulling out.

Research limitations/implications

The data collected are biased in favour of the financial/property perspective. Further research is therefore still required.

Practical implications

Despite its practical significance, no literature exists on this specific topic. The results reveal delays, disputes and sub‐optimal use of resources. Further research is needed leading to new official guidance covering all aspects of this process.

Originality/value

Large numbers of competitions are held in the UK each year. The disposal of sites in this way has become more significant due to the concentration of activity on brown‐field land. In future, the need to assemble urban land using compulsory purchase powers is likely to make competitions more frequent. These results, which highlight best practice, will be of interest to all professional people involved.
What is a library OPAC?
Authors: Wells David
Published: August 2007

Purpose

This paper aims to look at online public access catalogues (OPAC) operations in the light of the philosophy of information, communication theory and semiotics, and to revisit fundamental questions about the nature of library OPACs and the ways in which they function.

Design/methodology/approach

This exercise is pursued through examination of the multiple tensions implicit in any cataloguing or indexing system: the competing requirements of organisation and retrieval, description and classification.

Findings

The paper finds that for an OPAC to be practicably usable the potential complexity of the information it contains must be reduced to a manageable level of simplicity. OPACs purport to allow complete retrieval, even though data structures and index definitions are not transparent. They necessarily impose a framework of retrieval that conceals information at the same time as it presents it, and therefore to an extent they undermine the very concept of information literacy. In an online environment catalogues have been able easily to move beyond the scope of individual library collections and to incorporate an increasing range of non‐traditional types of information, thus introducing further tensions between their roles as indexes and as information sources in their own right.

Originality/value

The multiple tensions involved can be conceptualised in terms of indeterminacy of the communication code and indeterminacy of the linguistic sign. A clear theoretically‐based understanding of these issues is essential to ensuring optimal OPAC design.
SMS reference: keeping up with your clients
Authors: Herman Sonia
Published: August 2007

Purpose

In an attempt to meet evolving client needs, Southbank Library needed to become more flexible in the way services were delivered. The paper investigates whether providing a short message service (SMS) for students to text the library for information would offer a readily accessible alternative to e‐mail and live chat services.

Design/methodology/approach

SMS reference services where thoroughly researched in Australia and overseas to gage their usefulness for Southbank Institute libraries. Demographic statistics of the student population allowed researchers to determine how appropriate SMS reference technology would prove to be for library clients.

Findings

The paper finds that implementing SMS reference allowed the library the opportunity to access students via a familiar accessible service. SMS a Librarian has become part of the Southbank Institute Library Ask a Librarian service, which includes e‐mail, phone and live chat access for students and staff. By adding this new technology to the reference services, users are now able to send questions and receive answers from Southbank librarians by using the text messaging facility on their mobile phones.

Practical applications

SMS has become a popular way of communicating particularly among the younger generation. However, it is important that individual libraries evaluate the appropriateness of this technology for their clientele. For Southbank library it was a suitable technology as so many of the students use text messaging. It was felt that a large number of international students would benefit from this service. Often students with English as a second language feel more comfortable texting a question then using more conventional methods of communication. The success of the SMS reference service at Southbank Institute library revolves around three key points: SMS meets our clients' needs instantly; SMS is a relevant form of communication for students; and finally, the ease of providing SMS technology. Originality/value – When researching other educational institutions using SMS reference technology it became clear that universities were leading the field. Southbank Institute of Technology was the first vocational education institute to implement SMS reference and its experience should benefit similar skilled‐based training institutes.
RFID systems, standards and privacy within libraries
Authors: Butters Alan
Published: August 2007

Purpose

The goal of this paper is to provide an overview of the perceived threats of radio frequency identification (RFID) systems in libraries, to probe their technical feasibility and to present a clear picture of what may and may not be done by libraries to mitigate the risk that actually exists.

Design/methodology/approach

The current RFID standards are examined in the context of privacy and their limitations are weighed.

Findings

The paper finds that current standards do not offer a platform for secure RFID systems and have several vulnerabilities that may permit privacy compromising activities and acts of digital vandalism. It suggests that libraries need to be aware of these.

Research limitations/implications

The RFID application space is vast and spans multiple technology platforms and standards of which libraries are but a small part. Observations made regarding one application are not necessarily valid in another application.

Practical applications

The paper shows what could be done in the future by commercial RFID vendors to maintain compatibility with standards while maximising the data security and therefore borrower privacy of their systems.

Originality/value

No subject has so polarised libraries in recent years as the potential risk to personal privacy brought about by the introduction of RFID systems. It can be extremely difficult for libraries to accurately gauge the risks to the privacy of their borrowers in the context of rhetoric, which at times borders on the hysterical and is often misinformed. The paper addresses the myths and misconceptions and raises awareness of the issues.
Unlocking The Garage: a web portal for car enthusiasts
Authors: Fielding Elizabeth
Published: August 2007

Purpose

This paper seeks to look at the rationale, technical challenges and rewards involved in conceptually linking discrete digital resources in a way that is useful to the library's public.

Design/methodology/approach

Any subject analysis of reference enquiries submitted to state or public libraries over a given period is likely to identify car repair information as an enduring source of popular interest. The Garage web portal was developed in response to the very large number of requests – received over many years from both individuals and public libraries around the state of Queensland – for information about vehicle maintenance and restoration. Its inspiration was in the recognition that a substantial and potentially very useful part of the State Library's extensive collection in this area was not visible to the public.

Findings

The Garage's technical achievement was in bringing together the impressive, ten‐year indexing effort of two expert volunteers and a unique collection of several hundred historical photographs on Queensland motoring – and in making these available through a searchable portal on the State Library's web site.

Originality/value

The paper considers the opportunities inherent in opening up high demand areas in library collections and it offers an illustration of how expertise in the community can be shared with the library's wider public. It will be of value to anyone with an interest in capitalising on particular collection strengths in response to user driven demand – and it will be of particular interest to those who recognise car enthusiasts as a significant client group.
On the relation of systematic risk and accounting variables
Authors: Chiou Chei‐Chang , Su Robert K.
Published: August 2007

Purpose

This paper seeks to use an analytical approach to examine the relation of systematic risk and accounting variables.

Design/methodology/approach

The paper theoretically integrates the capital asset pricing model, Cobb‐Douglas function and clean surplus relation to derive the relation.

Findings

The analytical results suggest that determinants of systematic risk include earnings, sales growth, book value, dividend, degree of operating leverage (DOL), degree of financial leverage (DFL), market return, and risk‐free return. Three general conclusions are: For a firm with positive prior‐year earnings and current‐year sales growth, if the combined effect of its current book value, dividend and earnings on stock price is positive (negative), then its degree of total leverage has a positive (negative) effect on systematic risk; When the effect of book value and earnings on stock price each is positive and the effect of dividend on stock price is positive (negative), then the dividend has a positive (negative) effect on systematic risk; For a firm with positive (negative) sales growth, its DOL is positively (negatively) related with its DFL for a given level of systematic risk.

Originality/value

The findings have significant implications for the risk management literature and practice.
Size, book/market ratio and risk factor returns: evidence from China A‐share market
Authors: Chen Jianguo , Leong Kan Kwong , Anderson Hamish
Published: August 2007

Purpose

The purpose of this paper is to investigate the risk factors for A‐shares listed on both Shenzhen and Shanghai Stock Exchange in China using variables from Akgun and Gibson.

Design/methodology/approach

The paper applies cross‐sectional regression on the orthogonal components by rearranging these risk variables into several principal components.

Findings

The results produced strong evidence that size and book‐to‐market (BM) ratio could be well explained by these alternative risk variables. Additionally, the alternative variables are better at explaining returns in terms of adjusted R‐squares.

Practical implications

The practical implication of the study is that investors can improve both their pricing of the investment risk and their management of the risk factors with the alternatives identified in the study.

Originality/value

The paper provides evidence in explaining the size and BM effects in China's stock markets.
Dynamics of an electromagnetic linear actuator operating in error actuated control system
Authors: Nowak Lech , Radziuk Kazimierz
Published: August 2007

Purpose

The paper seeks to present an algorithm for a dynamical field‐circuit coupled simulation of an electromagnetic linear actuator operating in automated control systems.

Design/methodology/approach

The mathematical model includes: a transient electromagnetic field formulation for a non‐linear conducting and moving medium, equations which describe the electric circuits of the converter and the supply system, the equation of mechanical motion, the equation describing closed‐loop control and models for the sensor and the PID controller. The numerical implementation is based on the finite element method and the step‐by‐step algorithm for time discretization. In order to account for the nonlinearity of the ferromagnetic core the Newton‐Raphson procedure has been applied. The influence of the PID controller settings on the operation of the controlled actuator is shown. Dynamic disturbances, e.g. step change of the set value of mover position or change of loading force, have been analyzed.

Findings

The elaborated algorithm and the computer code can be an effective tool for field‐circuit simulation of the dynamics of an electromagnetic linear actuator operating in an automatic control system. Only tapered plunger should be used as multi‐stable actuators.

Originality/value

The study provides information of value in electromagnetic research.
Magnetic design considerations to improve nonlinear characteristics of inductively coupled power transfer systems
Authors: Kacprzak D. , Sykulski J.K.
Published: August 2007

Purpose

This study seeks to apply finite element analysis to study the proximity effect in a multi‐pickup inductively coupled power transfer system, quantify the effect and propose improved pick‐up configurations.

Design/methodology/approach

A mixture of approximate analytical formulae and accurate finite‐element simulations has been used as a tool for qualitative and quantitative analysis. Simplified consideration of magnetic flux paths aids understanding, whereas detailed numerical computation provides reliable performance prediction.

Findings

It is shown that a multi‐pickup formation of conventional E‐pickups may lead to power loss due to negative coupling between neighbouring pickups and that the phenomenon is nonlinear. Thus, two novel configurations for multi‐pickup systems have been proposed, an alternately‐directed Z‐pickup and a spilt‐type E‐pickup, both showing improved linearity, increased total power and more efficient use of ferromagnetic material.

Research limitations/implications

The investigation aimed mainly at the electromagnetic performance, while economic issues will still need to be addressed.

Practical implications

The proposed pick‐up configurations may be very helpful in systems where improved performance is needed but space or configuration limitations restrict or eliminate the possibility of using other designs.

Originality/value

The finite‐element aided magnetic field simulation has proved invaluable in achieving difficult design objectives. The combination of a simplified analytical approach and detailed numerical analysis has provided a reliable tool for accomplishing improved designs.
Sub‐domain finite element method for efficiently considering strong skin and proximity effects
Authors: Dular Patrick , Sabariego Ruth V. , Gyselinck Johan , Krähenbühl Laurent
Published: August 2007

Purpose

This paper seeks to develop a sub‐domain perturbation technique to efficiently calculate strong skin and proximity effects in conductors within frequency and time domain finite element (FE) analyses.

Design/methodology/approach

A reference eddy current FE problem is first solved by considering perfect conductors. This is done via appropriate boundary conditions (BCs) on the conductors. Next the solution of the reference problem gives the source for eddy current FE perturbation sub‐problems in each conductor then considered with a finite conductivity. Each of these problems requires an appropriate volume mesh of the associated conductor and its surrounding region.

Findings

The skin and proximity effects in both active and passive conductors can be accurately determined in a wide frequency range, allowing for precise losses calculations in inductors as well as in external conducting pieces.

Originality/value

The developed method allows one to accurately determine the current density distributions and ensuing losses in conductors of any shape, not only in the frequency domain but also in the time domain. Therefore, it extends the domain of validity and applicability of impedance‐type BC techniques. It also offers an original way to uncouple FE regions that allows the solution process to be lightened, as well as efficient parameterized analyses on the signal form and the conductor characteristics.
Eddy current influence on electromagnetic emissions of laminated cores
Authors: Duchesne Stéphane , Napieralska‐Juszczak Ewa , Roger Daniel
Published: August 2007

Purpose

A new model able to describe the high frequency (HF) behaviour of the laminated cores of AC machines is proposed. The aim is to compute the external flux density of machine cores, corresponding to electromagnetic emissions in the HF range when the skin effect is predominant.

Design/methodology/approach

For high frequencies, the skin depth is much lower than the thickness of a lamination and the external flux density is determined using a new analytical model. The validity of this model is confirmed by measurements performed on a magnetic core representing a small part of a large machine and a finite element 3D simulation.

Findings

For high frequencies, the external flux density is computed considering an equivalent current layer flowing on the laminated core external surface. Eddy currents in the laminated core have a large influence on the current density in this current layer.

Research limitations/implications

The new model proposed is valid when the skin depth is lower than half the thickness of a lamination.

Practical implications

The knowledge of the machine magnetic core behaviour in the frame of the HF electromagnetic emissions has practical applications for large AC machine maintenance such as the localization of partial discharges in the winding insulation. With this model, it is possible to analyse the information given by small magnetic sensors placed between the machine core and the external frame to solve all the insulation problems.

Originality/value

The new proposed model is able to establish a link between the electric HF phenomena in the windings of a working machine and the magnetic flux density outside the laminated core.
Reduction of force exciting influences to decrease radiation of acoustic noise in synchronous machines
Authors: Schulte Stephan , Hameyer Kay
Published: August 2007

Purpose

The paper aims to provide an approach to actively decrease the radiation of acoustic noise in synchronous machines.

Design/methodology/approach

Splitting regular three‐phase windings of synchronous machines into two independent three‐phase systems allows for an active influence of the current waveform if both winding systems are mutually displaced against each other. The harmonics content of each phase‐current varies due to the mutual inductive coupling with participating currents of both systems. Therefore, the ensuing force‐density distribution on the stator teeth varies accordingly. Resulting structure dynamics and furthermore the radiation of relevant harmonics of the acoustic noise are based on the mechanical excitation of considered force‐density distributions.

Findings

Configurations of mutual displacement of phase windings of both winding systems with significant decrease of mechanical deformation and emitted acoustic noise are found. Simulation methods to entirely describe and prove the behavior described are developed.

Research limitations/implications

The proposed approach is developed for a particular synchronous machine. Other machine types are conceivable for analysis in the same manner. Tools need to be adapted. Universal and reliable statements regarding acoustic behavior depend on the mechanical restraint of the machine and may therefore vary.

Practical implications

Active force‐density distribution is used for the noise reduction of alternators in vehicle applications. Additionally, wind‐power generators are considered for the application of split stator winding systems to actively counteract inhomogeneous force distributions on the rotor, evoked by stalling of the propeller blades during pole passing.

Originality/value

Active force‐density modification by stator winding modifications allows for the decrease of noise radiation of electrical machines with rotating‐field windings. Innovative simulation methods developed may now replace prototyping partially.
Analysis of a rotational single sheet tester using 3D finite element model taking into account hysteresis effect
Authors: Leite Jean V. , Benabou Abdelkader , da Silva P.A. , Sadowski N. , Henneron Thomas , Clénet Stéphane , Kuo‐Peng P. , Piriou Francis , Batistela N.J.
Published: August 2007

Purpose

The magnetic field strength measurement in a rotational single sheet tester (RSST) is quite difficult to achieve. In fact, flux leakage perturbs the field sensors as well as the homogeneity in the sample area. This paper seeks to present a 3D finite element (FE) model of an RSST taking into account a vector hysteresis model. The use of such model allows analyzing with accuracy the magnetic behavior of the system.

Design/methodology/approach

A vector hysteresis model, which is based on a general vectorization of the scalar Jiles‐Atherton model, is incorporated in a 3D FE code, with vector potential formulation.

Findings

The vector hysteresis model is validated by comparison with rotational experimental results. A good agreement is observed between calculations and measurements.

Originality/value

This paper shows that a classical scalar hysteresis model can be extended to take into account the magnetic vector behaviour and can be included in a 3D FE code. The methodology for the hysteresis including in the FE formulation is shown. This is useful for the design and analysis of an RSST prototype, improving the measurement techniques.
Comparison of different iron core models of three‐phase core‐type transformers
Authors: Dolinar Matjaž , Dolinar Drago , Štumberger Gorazd , Polajžer Boštjan
Published: August 2007

Purpose

The majority of three‐phase dynamic transformer models used in commercially available electric power system transient simulation programs offer only saturated three‐phase transformer models built from three single‐phase transformer models. This paper sets out to deal with the modelling and transient analysis of a saturated three‐limb core‐type transformer.

Design/methodology/approach

Three iron core models I‐III are given by the current‐dependent characteristics of flux linkages. In the first model, these characteristics are given by a set of piecewise linear functions, which include saturation. In the second model, the piecewise linear functions are replaced by the measured nonlinear characteristic. The more complex third model is given by a set of measured flux linkage characteristics.

Findings

The behaviour of transformers used in electric power applications depends considerably on the properties of magnetically nonlinear iron core. The best agreement between the calculated and measured results is obtained by use of the most complex iron core model III, which takes into account magnetic cross‐couplings between different limbs, caused by saturation.

Research limitations/implications

Measurement of the current‐dependent flux linkage characteristics of the 0.4 kV, 3.5 kVA laboratory transformer requires corresponding excitation of windings by three independent linear amplifiers. Current‐dependent flux linkage characteristics of the larger power transformer can be determined either by similar measurement with linear amplifiers of an appropriate power or by extracting them from the calculated magnetic field, which is done by the finite element method.

Practical implications

A three‐phase dynamic transformer model with the obtained iron core model III is suitable for the numerical analysis of nonsymmetric transient states in power systems.

Originality/value

This paper presents a three‐phase dynamic transformer model with an original iron core model III, which accounts for magnetic cross‐couplings between different limbs, caused by saturation.
Numerical model of a thermoelastic actuator solved as a coupled contact problem
Authors: Doležel Ivo , Karban Pavel , Ulrych Bohuš , Pantelyat Mykhailo , Matyukhin Yuriy , Gontarowskiy Pavlo
Published: August 2007

Purpose

The purpose of this paper is to investigate the parameters and operation characteristics of an actuator working on the principle of thermoelasticity whose structure was designed by the authors.

Design/methodology/approach

The mathematical model of the system describes the effects of three physical fields (electromagnetic field, temperature field, and field of mechanical strains and stresses due to thermoelasticity). While the electromagnetic field was solved independently, the thermomechanical task in common with the contact problem was solved in the hard‐coupled formulation. The computations were mostly carried out by own codes.

Findings

This type of actuator is characterized by extremely high forces acting in its dilatation element.

Research limitations/implications

The parameters of the system may still be improved using a longer field coil and dilatation element. Attention has to be paid, however to the mechanical stability of the system. Another improvement could be achieved by suitably designed cooling of the coil that would allow increasing parameters of the field current (its frequency or amplitude).

Practical implications

The device is promising for various fixing tasks in the industrial environment.

Originality/value

Although the methods of numerical processing of particular fields are known, the paper provides an algorithm for their simultaneous solution while respecting the temperature dependencies of the material properties and continuous change of the contact surfaces.
Dynamical analysis for flaw shape identification in non linear eddy current tests
Authors: Cacciola Matteo , Costantino Domenico , Carlo Morabito Francesco , Versaci Mario
Published: August 2007

Purpose

The paper seeks to propose a specific approach based on Dynamic Analysis and Chaos Theory aiming to emphasize the differences into the eddy current signals obtained by related non‐destructive tests, when the inspected specimens have flaws with different shapes.

Design/methodology/approach

Non‐linear eddy current analysis is very useful for flaw detection in many in‐service inspections. State‐of‐the‐art technologies allow one to define position and depth of defects, but the shape identification is still an open problem. In this paper, experimental data have been subjected to a dynamical analysis in order to relate the trend of eddy current signals to the shape of analyzed defect.

Findings

In particular, a dynamical reconstruction by means of recurrence plots (RPs) has been carried out in order to detect analogies and differentiations between different eddy current signals. Moreover, cross‐correlation between RPs of a reference benchmark and testing eddy current signals has been applied in order to emphasize a different dynamical behaviour and to detect a particular flaw's shape. In this way, a real‐time algorithm for defect shape classification has been performed.

Originality/value

Proposed approach is very interesting, and it is an innovation in non‐destructive testing procedures. In fact, the shape identification of a flaw is still an open challenge. The proposed approach, based on dynamic analysis, gives the key to solve this particular ill‐posed problem, by introducing a relation between the eddy current measurements and the shape of defect existing in the inspected specimen. Very interesting preliminary results have been obtained.
Applications of phase‐plane analysis to thyristor modelling
Authors: Paisana Júlio , Abreu Santos H.
Published: August 2007

Purpose

The aim of this study is to develop a thyristor model based on the general equations of the semiconductors.

Design/methodology/approach

Within the theory of the systems, the paper starts with the identification of the regenerative feedback current loop present in the p‐n‐p‐n structures. By using phase‐plane analysis and bifurcation theory, it analyses the stability of the different states of the devices and, at the same time, identifies the different characteristic critical points. The analysis of the non‐homogeneous solutions which can bifurcate from the uniform carrier distributions in the thyristor bases gives a further insight about the nature of the switching process.

Findings

A link between the electric bistable characteristics of thyristors and their physical and geometrical properties was found.

Practical implications

The main implication of this work is the acquisition of a method to implement a thyristor model for circuit analysis purposes where the different model parameters can be extracted from the respective device data sheets by using analytical methods.

Originality/value

The simulation of some particular characteristics of the thyristor by numerical methods has been described in other original works of the authors for the non‐homogeneous case. Here, the search is mainly to apply some of the more important findings of the work to a first‐level lumped thyristor model to be used in circuit analysis applications.
Sensorless control of PMSM drive with state and load torque estimation
Authors: Janiszewski Dariusz , Muszyński Roman
Published: August 2007

Purpose

The purpose of this paper is to obtain a fully sensorless permanent magnet synchronous motor (PMSM) drive control algorithm used for robot arm drive with load recognition. The paper shows how to use an extended Kalman filter (EKF) instead of sensors of the mechanical quantities as well as how to adapt the model of the PMSM to the filter procedures and aims at the real time application in the field‐oriented control (FOC) structure of the high‐dynamic drive.

Design/methodology/approach

The synthesis of the control system is based on the method of the FOC, theory of the EKF and object description in the form of state equation with suitable choice of state vector. The adequate connection of these three methodologies is a core of the approach to design. First, the control algorithm was tested by means of simulation method then the real laboratory plant was built and investigated.

Findings

Owing to task‐oriented formulation of the PMSM model, adequate organization of the EKF procedures and suitable choice of covariance matrices the proper control algorithm was obtained. The algorithm can be applied on DSP and gives a good result for the high dynamic drive in spite of the fact that the Kalman procedures are recognized as a time‐consumed solution of the estimation problem.

Research limitations/implications

The proposed algorithm can be used also in the case of another type of drive, for instance induction motor drive, although the model of the motor has a different formula. A disadvantage of the method is lack of the general rules for choosing the elements of the covariance matrices.

Practical implications

The presented algorithm is written in open‐programming language. Obtained results may be important for synthesis of robot arm drive, where the information about load forces is needed.

Originality/value

The paper presents an original sensorless vector control of PMSM with load recognition based on EKF. The originality elements are the choice of the covariance matrix elements and the real‐time realisation of the algorithm on the DSP.
Improved direct torque and flux control of induction motor drive
Authors: Sikorski Andrzej , Korzeniewski Marek
Published: August 2007

Purpose

The aim of the paper is to conduct an analytical study of a new method of induction motor torque and flux direct control with nonlinear controllers.

Design/methodology/approach

The method is based on the inverter state predictive determination in order to minimize the torque and flux errors.

Findings

The proposed method allows one to eliminate known DTC disadvantages, i.e. the hexagonal flux shape and nonsinusoidal current at a low motor speed, and also secures a decrease of torque and flux pulsation.

Practical implications

This new method enables a more precise reproduction of the motor torque and flux command signals, working with the same sampling frequency of the control processor as in the case of the standard DTC method. The decreased torque pulsations cause a decrease of the motor speed pulsation.

Originality/value

An innovative optimal control method is presented. The correctness of the initial assumptions as well as the expected final results have been verified in practice.
Customer service in the Baltic region: an exploratory analysis
Authors: Johnson Carol J. , Grimm Curtis M. , Blome Valdis
Published: August 2007

Purpose

The goal of this research is to identify which service activities contribute most to customer satisfaction in the technical wholesale industry in the Baltic States.

Design/methodology/approach

In order to obtain an understanding of customer service in the countries of Latvia, Lithuania, and Estonia, a mail survey was done to investigate customer service obtained by 184 customers of a large technical wholesale firm doing business in the Baltic States.

Findings

The overall results of this research indicate that in the technical wholesale industry of the Baltic countries customer service contributes to customer satisfaction. Of the six dimensions tested, all of the relationships were in the expected direction. Only one did not contribute significantly to customer satisfaction. In order of importance to customer satisfaction the dimensions are: process quality, product quality, delivery quality, communication, availability and product support.

Research limitations/implications

To obtain more generalizable results, future research areas should include investigating the model using other firms within the same industry, and testing the model in additional industries within the Baltics. Additional research may include testing the model in other countries in Northern and Central Europe such as the well‐developed Scandinavian countries, and the lesser developed countries of Slovakia, the Czech Republic, and Poland as well as other areas of the world. This model was tested using data from the technical wholesale industry and additional research may focus on testing the model across different industries in different countries as well.

Practical implications

The results are of relevance to practitioners, in particular for firms expanding to the Baltic area. In addition, anecdotal evidence suggests that the level and number of customer service activities provided by technical services firms in the Baltic area of Northern Europe are based solely on management judgment or practices borrowed from competitors without considering the impact of service provision on customer satisfaction. Instead practitioners should consider the process used to deliver services and products.

Originality/value

This is the first empirical work measuring the impact of customer service dimensions on customer satisfaction using data from the Baltic States.
Building supply chain collaboration: a typology of collaborative approaches
Authors: Whipple Judith M. , Russell Dawn
Published: August 2007

Purpose

This research aims to examine the characteristics, requirements, benefits, and barriers to various collaborative relationships and proposes a typology of collaborative approaches.

Design/methodology/approach

The research discusses insights and observations from exploratory interviews with 21 managers from ten different manufacturers and retailers.

Findings

A typology of three types of collaborative approaches (collaborative transaction management; collaborative event management; and collaborative process management) is proposed. The three collaborative approaches are compared and contrasted. Benefits and limitations associated with each type of collaboration are discussed.

Practical implications

Managers can use the typology to assess current collaborations and seek ways to improve current collaborative efforts. Managers can also use the typology to develop collaborative strategies across a broad spectrum of relationships in order to determine which type of collaboration best fits each individual business relationship.

Originality/value

This research extends previous relationship typologies by focusing specifically on collaborative relationships. The research examines various types of collaborative relationships in order to categorize collaborative approaches in a manner useful to academicians and practitioners.
Managing complexity in agile global fashion industry supply chains
Authors: Masson Ron , Iosif Laura , MacKerron Grant , Fernie June
Published: August 2007

Purpose

The purpose of this paper is to examine the agile supply chain management practices adopted by UK clothing retailers in order to effectively manage the supply of innovative, high‐margin, high‐fashion content product offerings in a complex global environment.

Design/methodology/approach

A case study approach was adopted examining the whole of the global retail fashion supply chain, from typical UK‐based retailers through to their main production and logistics suppliers based in two low‐cost locations, China and Romania. The cases of the UK retailers were followed by a study tour of China and Romania, where ten cases of fabric and finishing manufacturers, intermediaries and logistic providers were carried out.

Findings

Many aspects of accepted risk management and agile practice, such as market sensitivity, postponement activities and collaborative information‐sharing partnerships were apparent in the early product definition and the later product delivery stages of the supply chain. However, the responsibility for supply, including the key aspect of managing the complex supply network, was almost exclusively left to intermediaries located in low‐cost countries. These intermediaries in the main could best achieve agile supply from a significantly underutilized low‐cost country supply network through a traditional adversarial price and lead time auction sourcing process.

Research limitations/implications

While the cases considered reflected what seemed to be a typical and widely adopted approach to managing such a supply chain, this may not, of course, be the only approach taken by organisations in the clothing industry.

Originality/value

By examining a whole supply chain associated with agile supply in an important sector, the paper identifies the relative importance of some existing practices and brings into sharper focus those most relevant to this type of supply. The paper also identifies key elements of contemporary supply chain management practice, namely the growing use of global supply for innovative products and the essential and valuable role played by intermediaries in such supply chains.
An analysis of mobile credit card usage intentions
Authors: Amin Hanudin
Published: August 2007

Purpose

Many banks consider mobile‐based technologies have improved the banking services through introduction of new banking facilities. One of the latest facilities developed in this area is the “mobile credit card.” The purpose of this study is to examine the factors that determine intention to use mobile credit card among Malaysia bank customers, as their new way in conducting payment transactions.

Design/methodology/approach

The technology acceptance model (TAM) was used as the base model in order to develop the modified version of TAM to better reflect mobile credit card. In the modified model, perceived credibility and the amount of information on mobile credit card were added, in addition to perceived usefulness and perceived ease of use.

Findings

Results suggest that perceived usefulness, perceived ease of use, perceived credibility and the amount of information on mobile credit cards are important determinants to predict Malaysia bank customers' intentions to use mobile credit card. Needless to say, the paper is exploratory in nature.

Research limitations/implications

This study suffers from two limitations. The discussion of these limitations is provided in the last part of this paper.

Practical implications

Useful to Islamic banking institutions planning further mobile credit card services for their customers.

Originality/value

Extends the understanding of TAM to newly emerging context of mobile credit.