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Article
Publication date: 3 May 2013

Sonia Cafieri, Leo Liberti, Fre´de´ric Messine and Bertrand Nogare`de

The purpose of this paper is to investigate the impact of different mathematical formulations of the problem of optimal design of electrical machines on the results obtained using…

Abstract

Purpose

The purpose of this paper is to investigate the impact of different mathematical formulations of the problem of optimal design of electrical machines on the results obtained using a local optimization solver. The aim is to investigate the efficiency and reliability of standard local solvers when handling different mathematical formulations. This could provide guidelines for designers in practical engineering applications.

Design/methodology/approach

The paper proposes six equivalent mathematical formulations of the optimal design problem of a slotless permanent‐magnet electric rotating machine. The authors investigate the impact of these different mathematical formulations on the results obtained using a local optimization solver which is well‐known in the engineering community: MatLab's fmincon function. The paper first computationally compares the six proposed formulations with a fixed value for the number of pole pairs p, that gives continuous optimization problems, then discusses some results when p is free on three mixed‐integer formulations.

Findings

The paper shows that, even though the considered formulations are mathematically equivalent, their numerical performances are different when an optimization solver, such as the one proposed by MatLab in fmincon, is used. Thus, the designer must take care about the formulation of the design problem in order to make more efficient the use of these kind of algorithms.

Originality/value

In the context of engineering applications, one usually resorts to well known and easy to use optimization solvers. The same optimization problem can be often formulated in different ways. Furthermore, the formal description of optimization problems has an impact on the applicability and efficiency of the corresponding solution methods. This is usually not taken into account when optimization solvers are exploited. The originality of this paper is in building on the theory of reformulations in mathematical optimization to investigate and highlight the impact of formulation differences.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 32 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 1 June 2000

A. Savini

Gives introductory remarks about chapter 1 of this group of 31 papers, from ISEF 1999 Proceedings, in the methodologies for field analysis, in the electromagnetic community…

1128

Abstract

Gives introductory remarks about chapter 1 of this group of 31 papers, from ISEF 1999 Proceedings, in the methodologies for field analysis, in the electromagnetic community. Observes that computer package implementation theory contributes to clarification. Discusses the areas covered by some of the papers ‐ such as artificial intelligence using fuzzy logic. Includes applications such as permanent magnets and looks at eddy current problems. States the finite element method is currently the most popular method used for field computation. Closes by pointing out the amalgam of topics.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 19 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 4 May 2012

Ramzi Ben Ayed and Stéphane Brisset

The purpose of this paper is to investigate the use of multidisciplinary optimization (MDO) formulations within space‐mapping techniques in order to reduce their computing time.

Abstract

Purpose

The purpose of this paper is to investigate the use of multidisciplinary optimization (MDO) formulations within space‐mapping techniques in order to reduce their computing time.

Design/methodology/approach

The aim of this work is to quantify the interest of using MDO formulations within space mapping techniques. A comparison of three MDO formulations is carried out in a short time by using an analytical model of a safety transformer. This comparison reveals the advantage of two formulations in terms of robustness and computing time among the three MDO formulations. Then, the best formulations are investigated within output space mapping, using both analytical and FE models of the transformer.

Findings

A major computing time gain equal to 5.5 is achieved using the Individual Disciplinary Feasibility formulation within the output space‐mapping technique in the case of the safety transformer.

Originality/value

The MultiDisciplinary Feasibility formulation is the common formulation used within space‐mapping technique because it is the most conventional way to perform MDO. The originality of this paper is to investigate the Individual Disciplinary Feasibility formulation within output space‐mapping technique in order to allow the parallelization of calculation and to achieve a major reduction of computing time.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 31 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 1 April 2004

Soner Taslak

This study analyzes the problems restricting success of formulation and implementation of strategic decisions and tests whether there are meaningful differences between firm…

2231

Abstract

This study analyzes the problems restricting success of formulation and implementation of strategic decisions and tests whether there are meaningful differences between firm groups categorized by success levels obtained in strategic decision making and implementing processes by dealing with each problem. The Turkish textile industry was examined in this study. Five formulation problems and six implementation problems were frequently experienced by the sample group. Findings showed that the most important formulation problem was “uncertainties arising from national economic conditions”, and the two of most important implementation problems were “implementation activities taking more time than originally planned”, and “uncontrollable factors in the external environment”. ANOVA results demonstrated that there were meaningful diversities among firms attained different success level for four formulation and two implementation problems.

Details

European Business Review, vol. 16 no. 2
Type: Research Article
ISSN: 0955-534X

Keywords

Article
Publication date: 1 January 1992

ZHI‐HUA ZHONG and JAROSLAV MACKERLE

Contact problems are among the most difficult ones in mechanics. Due to its practical importance, the problem has been receiving extensive research work over the years. The finite…

Abstract

Contact problems are among the most difficult ones in mechanics. Due to its practical importance, the problem has been receiving extensive research work over the years. The finite element method has been widely used to solve contact problems with various grades of complexity. Great progress has been made on both theoretical studies and engineering applications. This paper reviews some of the main developments in contact theories and finite element solution techniques for static contact problems. Classical and variational formulations of the problem are first given and then finite element solution techniques are reviewed. Available constraint methods, friction laws and contact searching algorithms are also briefly described. At the end of the paper, a bibliography is included, listing about seven hundred papers which are related to static contact problems and have been published in various journals and conference proceedings from 1976.

Details

Engineering Computations, vol. 9 no. 1
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 20 April 2012

Jan Henrik Sieg, Alban Fischer, Martin W. Wallin and Georg von Krogh

This paper seeks to contribute to the discussion of relationship marketing in professional services firms (PSF). The process of dialogical interaction with clients is central to…

1517

Abstract

Purpose

This paper seeks to contribute to the discussion of relationship marketing in professional services firms (PSF). The process of dialogical interaction with clients is central to relationship marketing. However, client dialogue may fall dormant if not properly cultivated by employees of the PSF, that is, by professionals. This inductive study aims to investigate how professionals sustain a fruitful client dialogue by proactively introducing additional client problems to the dialogue.

Design/methodology/approach

Extensive field research with a “Big Four” accounting firm and 11 client companies inductively generates a framework to describe how professionals engage in proactive diagnosis of client problems to introduce these problems to the client dialogue. The framework is grounded in 49 focused interviews with professionals and client managers, as well as supplementary interviews, observations, and firm documents.

Findings

The suggested framework consists of the components of proactive diagnosis (information‐seeking and influence strategies), a trade‐off that professionals must make among these components, several enablers of and constraints on proactive diagnosis, and key client concerns that professionals must address to introduce additional client problems.

Originality/value

Despite the importance of client dialogue for relationship marketing, recommendations about how professionals can sustain client dialogue over time remain limited. This study describes proactive diagnosis as one potential approach. It contributes to literature on relationship marketing in PSFs by showing how proactive diagnosis helps professionals overcome the problem of dormancy in client dialogue, complements personal selling, and extends the role of diagnosis beyond paid client assignments into the pre‐selling phase.

Details

Journal of Service Management, vol. 23 no. 2
Type: Research Article
ISSN: 1757-5818

Keywords

Article
Publication date: 1 May 1986

Harry Henry

Properly conceived, conducted and interpreted, motivation research can be an extremely powerful management tool, designed to help the manufacturer or advertiser to sell more…

5995

Abstract

Properly conceived, conducted and interpreted, motivation research can be an extremely powerful management tool, designed to help the manufacturer or advertiser to sell more goods. Its aim is to expose the market situation, explain it and suggest courses of action which will lead to desired changes. It is a way of looking at a problem rather than a collection of specialist techniques and is strictly practical. Hence it can be used alongside other market research tools for the solution of marketing problems and can be applied to a wide range of business activities. Much of its development has been in the advertising field but it can also help in the formulation of production policy, solving packaging problems and marketing operations. It is examined here in all these contexts. The idea of motivation research, the reasons for its use and the techniques by which to apply it are discussed, as well as the pitfalls that are likely to occur. New and imaginary case studies are used throughout to illustrate points. A review of the subject literature is included.

Details

Marketing Intelligence & Planning, vol. 4 no. 5
Type: Research Article
ISSN: 0263-4503

Keywords

Article
Publication date: 1 January 2024

Masoud Parsi, Vahid Baradaran and Amir Hossein Hosseinian

The purpose of this study is to develop an integrated model for the stochastic multiproject scheduling and material ordering problems, where some of the prominent features of…

Abstract

Purpose

The purpose of this study is to develop an integrated model for the stochastic multiproject scheduling and material ordering problems, where some of the prominent features of offshore projects and their environmental-degrading effects have been embraced as well. The durations of activities are uncertain in this model. The developed formulation is tri-objective that seeks to minimize the expected time, total cost and CO2 emission of all projects.

Design/methodology/approach

A new version of the multiobjective multiagent optimization (MOMAO) algorithm has been proposed to solve the amalgamated model. To empower the MOMAO, various procedures of this algorithm have been modified based on the multiattribute utility theory (MAUT) technique. Along with the MOMAO, this study has employed four other meta-heuristic methodologies to solve the model as well.

Findings

The outputs of the MOMAO have been put to test against four other optimizers in terms of convergence, diversity, uniformity and computation times. The results of the Mean Ideal Distance (MID) metric have revealed that the MOMAO has strongly prevailed its rival optimizers. In terms of diversity of the acquired solutions, the MOMAO has ranked the first among all employed optimizers since this algorithm has offered the best solutions in 56.66 and 63.33% of the test problems regarding the diversification metric and hyper-volume metrics. Regarding the uniformity of results, which is measured through the spacing metric (SP), the MOMAO has presented the best SP values in more than 96% of the test problems. The MOMAO has needed more computation times in comparison to its rivals.

Practical implications

A real case study comprising two concurrent offshore projects has been offered. The proposed formulation and the MOMAO have been implemented for this case study, and their effectiveness has been appraised.

Originality/value

Very few studies have focused on presenting an integrated formulation for the stochastic multiproject scheduling and material ordering problems. The model embraces some of the characteristics of the offshore projects which have not been adequately studied in the literature. Limited capacities of the offshore platforms and cargo vessels have been embedded in the proposed model. The offshore platforms have spatial limitations in storing the required materials. The vessels are also capacitated and they also have limited shipment capacities. Some of the required materials need to be transported from the base to the offshore platform via a fleet of cargo vessels. The workforces and equipment can become idle on the offshore platform due to material shortage. Various offshore-related costs have been integrated as a minimization objective function in the model. The cargo vessels release CO2 detrimental emissions to the environment which are sought to be minimized in the developed formulation. To the best of the authors' knowledge, the MOMAO has not been sufficiently employed as a solution methodology for the stochastic multiproject scheduling and material ordering problems.

Details

Engineering, Construction and Architectural Management, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0969-9988

Keywords

Book part
Publication date: 4 March 2024

Oswald A. J. Mascarenhas, Munish Thakur and Payal Kumar

We revisit the problem of redesigning the Master in Business Administration (MBA) program, curriculum, and pedagogy, focusing on understanding and seeking to tame its “wicked…

Abstract

Executive Summary

We revisit the problem of redesigning the Master in Business Administration (MBA) program, curriculum, and pedagogy, focusing on understanding and seeking to tame its “wicked problems,” as an intrinsic part and challenge of the MBA program venture, and to render it more realistic and relevant to address major problems and their consequences. We briefly review the theory of wicked problems and methods of dealing with their consequences from multiple perspectives. Most characterization of problems classifies them as simple (problems that have known formulations and solutions), complex (where formulations are known but not their resolutions), unstructured problems (where formulations are unknown, but solutions are estimated), and “wicked” (where both problem formulations and their resolutions are unknown but eventually partially tamable). Uncertainty, unpredictability, randomness, and ambiguity increase from simple to complex to unstructured to wicked problems. A redesigned MBA program should therefore address them effectively through the four semesters in two years. Most of these problems are real and affect life and economies, and hence, business schools cannot but incorporate them into their critical, ethical, and moral thinking.

Details

A Primer on Critical Thinking and Business Ethics
Type: Book
ISBN: 978-1-83753-312-1

Article
Publication date: 3 July 2017

Alex A. Schmidt, Alice de Jesus Kozakevicius and Stefan Jakobsson

The current work aims to present a parallel code using the open multi-processing (OpenMP) programming model for an adaptive multi-resolution high-order finite difference scheme…

Abstract

Purpose

The current work aims to present a parallel code using the open multi-processing (OpenMP) programming model for an adaptive multi-resolution high-order finite difference scheme for solving 2D conservation laws, comparing efficiencies obtained with a previous message passing interface formulation for the same serial scheme and considering the same type of 2D formulations laws.

Design/methodology/approach

The serial version of the code is naturally suitable for parallelization because the spatial operator formulation is based on a splitting scheme per direction for which the flux components are numerically computed by a Lax–Friedrichs factorization independently for each row or column. High-order approximations for numerical fluxes are computed by the third-order essentially non-oscillatory (ENO) and fifth-order weighted essentially non-oscillatory (WENO) interpolation schemes, assuming sparse grids in each direction. The grid adaptivity is obtained by a cubic interpolating wavelet transform applied in each space dimension, associated to a threshold operator. Time is evolved by a third order TVD Runge–Kutta method.

Findings

The parallel formulation is implemented automatically at compiling time by the OpenMP library routines, being virtually transparent to the programmer. This over simplifies any concerns about managing and/or updating the adaptive grid when compared to what is necessary to be done when other parallel approaches are considered. Numerical simulations results and the large speedups obtained for the Euler equations in gas dynamics highlight the efficiency of the OpenMP approach.

Research limitations/implications

The resulting speedups reflect the effectiveness of the OpenMP approach but are, to a large extension, limited by the hardware used (2 E5-2620 Intel Xeon processors, 6 cores, 2 threads/core, hyper-threading enabled). As the demand for OpenMP threads increases, the code starts to make explicit use of the second logical thread available in each E5-2620 processor core and efficiency drops. The speedup peak is reached near the possible maximum (24) at about 22, 23 threads. This peak reflects the hardware configuration and the true software limit should be located way beyond this value.

Practical implications

So far no attempts have been made to parallelize other possible code segments (for instance, the ENO|-WENO-TVD code lines that process the different data components which could potentially push the speed up limit to higher values even further. The fact that the speedup peak is located close to the present hardware limit reflects the scalability properties of the OpenMP programming and of the splitting scheme as well. Consequently, it is likely that the speedup peak with the OpenMP approach for this kind of problem formulation will be close to the physical (and/or logical) limit of the hardware used.

Social implications

This work is the result of a successful collaboration among researchers from two different institutions, one internationally well-known and with a long-term experience in applied mathematics for industrial applications and the other in a starting process of international academic insertion. In this way, this scientific partnership has the potential of promoting further knowledge exchange, involving students and other collaborators.

Originality/value

The proposed methodology (use of OpenMP programming model for the wavelet adaptive splitting scheme) is original and contributes to a very active research area in the past years, namely, adaptive methods for conservation laws and their parallel formulations, which is of great interest for the entire scientific community.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 27 no. 7
Type: Research Article
ISSN: 0961-5539

Keywords

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