bluuebunny/crossref_metadata_2025_split huggingface dataset:
Activation and electro‐dynamic dampers, key technologies for the operation of superconducting magnetic bearings
Authors: May Hardo , Hoffmann Jan , Canders Wolf‐Ruediger , Palka Ryszard 
Published: January 2009

PurposeThe purpose of this paper is to focus on superconducting magnetic bearings (SMB). SMB for high‐speed rotors are contact free and offer inherently stable operations thus they are best qualified for the support of horizontally aligned rotors of turbo machines for gas‐compressors and expanders, e.g. special attentions have to be concentrated on the force activation of the SMB without dislocating the rotor from the aligned position.Design/methodology/approachFor the activation of cylindrically shaped SMB‐designs, appropriate units with movable superconductor parts have been developed. They permit the maintenance of the rotor together with the field excitation unit in the aligned un‐displaced position. The eddy currents in the conducting cylinder of an EDD are induced by spatial fluctuations of the field and thus have been determined by transient calculations. The mechanical oscillation of the rotor was considered by a step‐wise displacement of the damper‐plate.FindingsAs the rotors of both the machine and the SMB operate best with reduced clearance to the stators, the shaft cannot be displaced to activate the force of horizontally aligned superconducting bearing assemblies. Thus, for cylindrical, co‐axial SMB‐designs the stator is shaped as two half shells embracing the SMB‐rotor. For the force activation the following procedure has to be carried out within the Dewar without displacing the shaft: at first the half shells are retreated from the rotor (warm HTSC) and after the cooling they are moved against the inner part of the warm bore thus generating the forces to compensate the weight and disturbances of the rotor. In case of planar‐cylindrical SMB‐designs, which are specially suited for extreme high speed applications, the bearing stators consist of a planar cylinder plate of HTSC‐bulks. The force activation is realised by lifting and descending the Dewar with the HTSC parts as a whole independently from the position of the rotor. The radial forces of the EDD and their partitioning in components which contribute to the damping‐ and to the spring‐force have been determined for different frequencies up to 160 Hz. To achieve accuracies in the percent range, the values of the time steps have to be well adapted to the electro dynamic conditions as oscillation frequency and conductivity.Originality/valueOnly the presented activation devices with movable HTSC stator parts enable the application of SMB even for horizontally aligned high‐speed rotors with reduced radial clearance. The recently developed fully integrated EDD secure a safe run of the rotor even during the speed up – passing the eigenfrequency in particular.
Analysis of non‐stationary electric signals using the S‐transform
Authors: Leonowicz Zbigniew , Lobos Tadeusz , Wozniak Krzysztof 
Published: January 2009

PurposeThe purpose of this paper is to compare the accuracy of tracking the amplitude and frequency changes of non‐stationary electric signals.Design/methodology/approachShort‐time fourier transform (STFT) and S‐transform algorithms were applied to analyze non‐stationary signals originating from switching of capacitor banks in a power system.FindingsThe S‐transform showed possibilities of sharp localization of the basic component, and allowed improvement of tracking dynamism the transient components in comparison to STFT.Practical implicationsS‐transform is a better tool for the analysis of non‐stationary waveforms in power systems and its properties can be used for diagnostic and power quality applications.Originality/valueThe dynamic tracking of the changes in time and frequency of real‐like signals originating from a power system are investigated in this paper.
Numerical model of vagus nerve electrical stimulation
Authors: Szmurlo Robert , Starzynski Jacek , Wincenciak Stanislaw , Rysz Andrzej 
Published: January 2009

PurposeThe electric stimulation of the vagus nerve is used to obtain therapeutic results in epilepsy, depression and Alzheimer diseases. The purpose of this paper is to show numerical model of stimulation, focusing on the mathematical approach to modeling a phenomenon of neural cells activation and its propagation in the nerve.Design/methodology/approachThe paper presents a model based on the bidomain theory. It uses two continuous, averaged domains which depict the intra‐ and extra‐cellular domains and are connected with the membrane ionic currents. The numerical model uses 3D cylindrical model approximating the anatomical shape of the neck. The simulator is based on a time domain finite element method.FindingsThe presented approach allows to model the discrete behaviour of the membrane potential in the macroscopic, realistic model of the nerve. The validation of the parameters with the velocity of activation propagations suggests the strong disscussion on physical interpretation to the bidomain theory parameters. To obtain realistic results the parameters needed to be unrealistic.Originality/valueThe paper presents the combination of bidomain model of neural tissue with the time domain finite element method along with the atributes of bidomain model for realistic modeling of the process of propagtion of activation.
Object shape virtualization in impedance tomography
Authors: Grzywacz Tomasz , Sikora Jan , Wójtowicz Stefan 
Published: January 2009

PurposeThe purpose of this paper is to introduce a method for increasing imaging quality in impedance tomography. The paper presents an optical method of shape virtualization, processing algorithm draft and results of virtualization for sample objects.Design/methodology/approachIn impedance tomography the image reconstruction algorithms must yield accurate images of impedance changes. One of the keys to producing an accurate reconstructed image is the inclusion of prior information regarding the physical geometry of the object. When the object under investigation is filled with transparent medium, optical methods can provide information about its interior and estimate the shape of non‐transparent interjections. Computer graphics methods (e.g. ray tracing) can be used to simulate propagation of the light transmitted along straight lines within the object, and thus yield geometric data to better imaging. The process of setting up boundary conditions is then supplied with additional information about interior of the object, which can significantly improve solution of the forward problem in impedance tomography.FindingsThe visibility matrix includes information about the interior of the object. However, the information is incomplete since the scanning is done along one axis. In order to obtain all remaining data, scanning along three axes is required. On the basis of the visibility matrix, the shape and volume of the non‐transparent interjections are recovered and then estimated.Originality/valueThe biggest novelty is indeed the combination of methods used in optical tomography with those in impedance tomography.
Gene selection for cancer classification
Authors: Wiliński Artur , Osowski Stanisław 
Published: January 2009

PurposeThe purpose of this paper is to discover the most important genes generated by the gene expression arrays, responsible for the recognition of particular types of cancer.Design/methodology/approachThe paper presents the analysis of different techniques of gene selection, including correlation, statistical hypothesis, clusterization and linear support vector machine (SVM).FindingsThe correctness of the gene selection is proved by mapping the distribution of selected genes on the two‐coordinate system formed by two most important principal components of the PCA transformation. Final confirmation of this approach are the classification results of recognition of several types of cancer, performed using Gaussian kernel SVM.Originality/valueThe results of selection of the most significant genes used for the SVM recognition of seven types of cancer have confirmed good accuracy of results. The presented methodology is of potential use in practical application in bioinformatics.
Using history in organizations
Authors: Brunninge Olof 
Published: January 2009

PurposeThis paper aims to explore how organizational actors make reference to history and how they use historical reference purposefully in order to affect strategy‐making.Design/methodology/approachThe paper draws on in‐depth case studies on two Swedish MNCs. Data have been collected through 79 interviews as well as participant observation and archival studies.FindingsOrganizational actors purposefully construct and use history in order to establish continuity in strategy processes. The use of historical references legitimizes or delegitimizes specific strategic options.Research limitations/implicationsTwo old firms with a clear interest in organizational history have been studied. Future research on additional companies, including young firms and firms with less interest in history, is needed.Practical implicationsThe purposeful use of history can be a powerful tool for managers to influence organizational change processes.Originality/valueVery little research on the use of history in business organizations has so far been done. In an interdisciplinary manner the paper introduces concepts from research in history to management research. Based on two rich case studies the paper contributes by outlining what role different uses of history play in strategic and organizational change.
The genre of corporate history
Authors: Delahaye Agnès , Booth Charles , Clark Peter , Procter Stephen , Rowlinson Michael 
Published: January 2009

PurposeThis paper seeks to identify and define the genre of corporate history within the pervasive historical discourse produced by and about organizations which tells the past of an organization across a multiplicity of texts: published works – commissioned and critical accounts, academic tomes and glossy coffee‐table books – as well as web pages, annual reports and promotional pamphlets.Design/methodology/approachThe approach takes the form of systematic reading of historical narratives for 85 mainly British and US companies from the Fortune Global 500. For these companies, a search was carried out for US printed sources in the British Library and a survey was conducted of historical content in web pages.FindingsFrom extensive reading of the historical discourse, recurrent formal features (medium, authorship, publication, paratext and imagery) and elements of thematic content (narrative, characters, cultural paradigms and business success), which together define the genre of corporate history, have been identified. Such a definition provides competence in the reading of historical narratives of organizations and raises questions regarding the role of history in organizational identity, memory and communication. In conclusion it is argued that the interpretation of corporate history cannot be reduced to its promotional function for organizations.Research limitations/implicationsThe list of the formal features and thematic content of corporate history detailed here is by no means exhaustive. They are not variables, but signs, which, in various combinations, compose the narrative and signify the genre.Practical implicationsIt seems likely that coffee‐table books will increasingly replace academic commissioned histories, with consultants professionalizing the discourse and formalizing the genre of corporate history.Originality/valueThe genre of corporate history has hitherto been neglected in organization theory, where the linguistic turn has led to a preoccupation with talk as text. The use of genre to analyse corporate history represents a textual turn to literary organizational texts as text.
Path dependence, initial conditions, and routines in organizations
Authors: van Driel Hugo , Dolfsma Wilfred 
Published: January 2009

PurposeThe purpose of this paper is to disentangle and elaborate on the constitutive elements of the concept of path dependence (initial conditions and lock‐in) for a concerted and in‐depth application to the study of organizational change.Design/methodology/approachThe approach takes the form of a combination of a longitudinal and a comparative case‐study, based on secondary literature.FindingsExternal initial conditions acted less as “imprinting” forces than is suggested in the literature on the genesis of the Toyota production system (TPS); a firm‐specific philosophy in combination with a critical sequence of events mainly shaped and locked‐in TPS.Research limitations/implicationsThe empirical sources are limited to publications in English, so relevant factors explaining the path taken may not all have been included. The importance of a salient meta‐routine might be firm‐specific.Practical implicationsThe study contributes to understanding the factors underlying corporate performance by a critical re‐examination of a much heralded production system (TPS).Originality/valueThe paper highlights the use of the concept of meta‐routines to connect the core elements of path dependence, that is, sensitivity to initial conditions and lock‐in mechanisms.
Leadership style and entrepreneurial change
Authors: Karsten Luchien , Keulen Sjoerd , Kroeze Ronald , Peters Rik 
Published: January 2009

PurposeThis paper aims to look at the role of the top and middle management of the Philips organization during the transition from one type of organizational change to another in the 1990s and the role the history of the organisation played in this process.Design/methodology/approachThe paper analysis is based on historical records, literature and interviews with former Philips top managers.FindingsThe paper shows that Philips' leaders used different styles of leadership to create a deliberate atmosphere and willingness to change. The final emergent transformation, however, could only sufficiently materialise while it rejuvenated existing management concepts like Quality Management. The success was partly based on the fact that these concepts played a historical role in the Philips organisation.Originality/valueThe paper adds the historical style approach to leadership research and pays attention to the important role of the organization's history during processes of organizational change.
The nature of the changing role of first‐tier managers: a long‐cycle approach
Authors: Martins Lola‐Peach 
Published: January 2009

PurposeThe primary intention of this research paper is to systemically identify and discuss the longitudinal embedding of the nature of the changing role of first‐tier managers (FTMs) – drawing particular attention to the trends, typical characteristics and complexities associated with their role.Design/methodology/approachThe paper carried out a literature survey using a long‐cycle approach – a systemic and in‐depth survey of the literature from the early Industrial Revolution era to the twenty‐first century in order to pin‐point the main phases of the transition of the FTM's people management role. The author's four‐factor framework for decision making vis‐à‐vis the role of FTMs was used to trace whether the characteristics and issues linked with the role today are typical of those associated with the role in the past, and the degree to which lessons have been learned.FindingsImportantly, the long‐cycle analysis revealed that the FTM's role has been through three core phases from the early industrial revolution era, and is currently in the fourth phase. That is, the manager‐in‐charge, the manager‐in‐the‐middle, the manager‐on‐the‐margin and the manager‐in‐charge‐plus. Whilst drawing attention to the complexities associated with the evolution process, the cycle shows that it is possible to conceptualise each phase and identify the key factors linked to the FTM's changing role successively. This drew attention to the fact that the success or failure of this role can be determined by five key factors, which characterise it – definition of the role, training/development of FTMs, perception/attitude of the primary stakeholders of the role (including FTMs), broader organisational support of FTMs (whether lacking or present), and their performance/performance management. Furthermore, the findings showed that, if these key factors are not considered from an in‐depth historical perspective, the FTM's people management role will remain a major organisational dilemma.Research limitations/implicationsThe literature survey was quite general, although the literature on the manufacturing industry and the UK are the main focus.Originality/valueThe paper establishes the trends in the management of FTMs and their people management role using a long‐cycle approach. To date, few integrated studies on people management devolution to FTMs have been undertaken that seek to identify the key phases of the transition and the complexities associated with the evolution of the role during these times. Therefore, the paper addresses the imbalance by reflecting on the nature of the FTM's people management role over a long period, and developing a conceptual framework for pin‐pointing and analysing the problems faced in managing FTMs strategically.
Optimisation modelling for thermal fatigue reliability of lead‐free interconnects in fine‐pitch flip‐chip packaging
Authors: Stoyanov Stoyan , Bailey Chris , Desmulliez Marc 
Published: January 2009

PurposeThis paper aims to present an integratedoptimisation‐modellingcomputational approach for virtual prototyping that helps design engineers to improve the reliability and performance of electronic components and systems through design optimisation at the early product development stage. The design methodology is used to identify the optimal design of lead‐free (Sn3.9Ag0.6Cu) solder joints in fine‐pitch copper column bumped flip‐chip electronic packages.Design/methodology/approachThe design methodology is generic and comprises numerical techniques for computational modelling (finite element analysis) coupled with numerical methods for statistical analysis and optimisation. In this study, the integratedoptimisation‐modellingdesign strategy is adopted to prototype virtually a fine‐pitch flip‐chip package at the solder interconnect level, so that the thermal fatigue reliability of the lead‐free solder joints is improved and important design rules to minimise the creep in the solder material, exposed to thermal cycling regimes, are formulated. The whole prototyping process is executed in an automated way once the initial design task is formulated and the conditions and the settings for the numerical analysis used to evaluate the flip‐chip package behaviour are specified. Different software modules that incorporate the required numerical techniques are used to identify the solution of the design optimisation problem related to solder joints reliability optimisation.FindingsFor fine‐pitch flip‐chip packages with copper column bumped die, it is found that higher solder joint volume and height of the copper column combined with lower copper column radius and solder wetting around copper column have a positive effect on the thermo‐mechanical reliability.Originality/valueThe findings of this research provide design rules for more reliable lead‐free solder joints for copper column bumped flip‐chip packages and help to establish further the technology as one of the viable routes for flip‐chip packaging.
Lead‐free solder joint reliability estimation of flip chip package using FEM‐based sensitivity analysis
Authors: Lee Chang‐Chun , Chang Kuo‐Chin , Yang Ya‐Wen 
Published: January 2009

PurposeIntegration of Cu/low‐k interconnects into the next‐generation integrated circuit chips, particularly for devices below the 90 nm technology node, has proved necessary to meet the urgent requirements of reducing RC time delay and low power consumption. Accordingly, establishment of feasible and robust packaging technology solutions in relation to the structural design, as well as material selection of the packaging components, has become increasingly important. Moreover, the nature of low‐k materials and the use of lead‐free solder greatly increases the complications in terms of ensuring enhanced packaging level reliability. The foregoing urgent issue needs to be quickly resolved while developing various advanced packages. This paper aims to focus on the issues.Design/methodology/approachThe prediction model, especially for the fatigue life of lead‐free solder joints, combined with virtual design of experiment with factorial analysis was used to obtain the sensitivity information of selecting geometry/material parameters in the proposed low‐k flip‐chip (FC) package. Moreover, a three‐dimensional non‐linear strip finite element model associated with the two levels of specified boundary condition of global‐local technique was adopted to shorten the time of numerical calculation, as well as to give a highly accurate solution.FindingsThe results of thermal cycling in experimental testing show good agreement with the simulated analysis. In addition, the sensitivity of analysis indicates that the type of underfill material has a significant effect on the lead‐free solder joint reliability.Originality/valueA suitable combination of concerned designed factors is suggested in this research to enhance the reliability of low‐k FC packaging with Pb‐free solder joints.
The field of educational administration
Authors: Oplatka Izhar 
Published: January 2009

PurposeBased on journal articles that focused on epistemological issues in the field (e.g. the field's nature, purposes, borders, knowledge base, uniqueness, etc.), this paper seeks to outline the intellectual discussions in the field of educational administration (EA) since the foundation of its major journals and suggest some lessons for the state of the field at the present time.Design/methodology/approachThe review is based on all papers, scholarly, historical or empirical, that observed philosophical, epistemological and methodological issues and concerns in this field. The papers were analyzed and coded by their purposes, arguments, epistemological questions, criticism, findings and insights.Practical implicationsThe major concluding epistemological message of this historical account is of “recycling,” i.e. the field is typically embedded with debates over similar ideas, assumptions, and insights about EA as a field of study throughout the last five decades. Therefore, it is a time for radical changes in the understanding of the field's intellectual missions and boundaries.Originality/valueThe historical overview is likely both to acquaint one with the historical scholarly streams, trends and debates in knowledge development of EA as a field of study, and help international field members understand and mould their professional identity.