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Article
Publication date: 1 July 2006

Hokyung Shim, Heegon Moon and Semyung Wang

This research aims to present a 3D multi‐objective approach regarding both magnetic and thermal characteristics associated with design of actuators.

602

Abstract

Purpose

This research aims to present a 3D multi‐objective approach regarding both magnetic and thermal characteristics associated with design of actuators.

Design/methodology/approach

The adjoint variable topology sensitivity equations are derived using the continuum method for 3D optimization. Convection interpolation function is proposed for density method of topologies such that convection term can be taken into consideration for practical design in the process of the optimization. In application of a C‐core actuator, the sensitivity is verified using the finite difference method (FDM). The proposed method is applied to the C‐core actuator and a single‐phase induction motor.

Findings

The thermal field is much more sensitive than electromagnetics that the weighing factor is investigated in the SPIM. Optimal topology result shows that cutting is needed.

Originality/value

A 3D topology optimization for magnetic and thermal systems using the finite element method is proposed.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 25 no. 3
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 September 2004

Jenam Kang, Chwail Kim and Semyung Wang

This paper presents a probabilistic optimal design for electromagnetic systems. A 2D magnetostatic finite element model is constructed for a reliability‐based topology…

604

Abstract

This paper presents a probabilistic optimal design for electromagnetic systems. A 2D magnetostatic finite element model is constructed for a reliability‐based topology optimization (RBTO). Permeability, coercive force, and applied current density are considered as uncertain variables. The uncertain variable means that the variable has a variance on a certain design point. In order to compute reliability constraints, a performance measure approach is widely used. To find reliability index easily, the limit‐state function is linearly approximated at each iteration. This approximation method is called the first‐order reliability method, which is widely used in reliability‐based design optimizations. To show the effectiveness of the proposed method, RBTO for the electromagnetic systems is applied to magnetostatic problems.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 23 no. 3
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 December 2004

Semyung Wang, Seungkyu Park and Jenam Kang

The design of multi‐domain that considers all components of electromagnetic systems such as air, iron, magnet, and coil is investigated using topology optimization, interpolation…

644

Abstract

The design of multi‐domain that considers all components of electromagnetic systems such as air, iron, magnet, and coil is investigated using topology optimization, interpolation method, and FEM. The design sensitivity equation for topology optimization is derived using the adjoint variable method and the continuum approach. The proposed method is applied to topology optimization of C‐core actuator and shows significant improvement.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 23 no. 4
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 April 2006

Heon Lee, Heegon Moon, Semyung Wang and Kyungbae Park

Aims to discuss iron loss analysis and experimenting with linear oscillating actuator for linear compressor.

457

Abstract

Purpose

Aims to discuss iron loss analysis and experimenting with linear oscillating actuator for linear compressor.

Design/methodology/approach

The iron loss analysis of the linear oscillating actuator is performed by using ANSYS and iron loss curves, which is obtained by an Epstein test apparatus.

Findings

The way to calculate the iron loss of the linear oscillating actuator for the linear compressor and the method to experiment the iron loss of that can be studied.

Research limitations/implications

Iron loss analysis of the linear compressor considering the motor part and the structure part is needed.

Originality/value

Each iron loss analysis method examined here can be used to analyze the iron loss of the linear motor.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 25 no. 2
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 June 2000

K. Wiak

Discusses the 27 papers in ISEF 1999 Proceedings on the subject of electromagnetisms. States the groups of papers cover such subjects within the discipline as: induction machines;…

925

Abstract

Discusses the 27 papers in ISEF 1999 Proceedings on the subject of electromagnetisms. States the groups of papers cover such subjects within the discipline as: induction machines; reluctance motors; PM motors; transformers and reactors; and special problems and applications. Debates all of these in great detail and itemizes each with greater in‐depth discussion of the various technical applications and areas. Concludes that the recommendations made should be adhered to.

Details

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

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Article
Publication date: 1 June 2000

P.Di Barba

Introduces papers from this area of expertise from the ISEF 1999 Proceedings. States the goal herein is one of identifying devices or systems able to provide prescribed…

990

Abstract

Introduces papers from this area of expertise from the ISEF 1999 Proceedings. States the goal herein is one of identifying devices or systems able to provide prescribed performance. Notes that 18 papers from the Symposium are grouped in the area of automated optimal design. Describes the main challenges that condition computational electromagnetism’s future development. Concludes by itemizing the range of applications from small activators to optimization of induction heating systems in this third chapter.

Details

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

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Article
Publication date: 17 April 2023

Seung Uk Choi, Hyung Jong Na and Kun Chang Lee

The purpose of this study is to examine the relationship between explanatory language, audit fees and audit hours to demonstrate that auditors use explanatory language in audit…

494

Abstract

Purpose

The purpose of this study is to examine the relationship between explanatory language, audit fees and audit hours to demonstrate that auditors use explanatory language in audit reports to explain perceived audit risk.

Design/methodology/approach

The authors construct the sentiment value, a novel audit risk proxy derived from audit reports, using big data analysis. The relationship between sentiment value and explanatory language is then investigated. The authors present the validity of their new metric by examining the relationship between sentiment value and accounting quality, taking audit fees and hours into account.

Findings

The authors first find that reporting explanatory language is positively related to audit fees. More importantly, the authors provide an evidence that explanatory language in audit reports is indicative of increased audit risk as it is negatively correlated with sentiment value. As a positive (negative) sentimental value means that the audit risk is low (high), the results indicate that auditors describe explanatory language in a negative manner to convey the inherent audit risk and receive higher audit fees from the risky clients. Furthermore, the relationship is strengthened when the explanatory language is more severe, such as reporting the multiple numbers of explanatory language or going-concern opinion. Finally, the sentiment value is correlated with accounting quality, as measured by the absolute value of discretionary accruals.

Originality/value

Contrary to previous research, the authors’ findings suggest that auditors disclose audit risks of client firms by including explanatory language in audit reports. In addition, the authors demonstrate that their new metric effectively identifies the audit risk outlined qualitatively in audit report. To the best of the authors’ knowledge, this is the first study that establishes a connection between sentiment analysis and audit-related textual data.

Details

Managerial Auditing Journal, vol. 38 no. 6
Type: Research Article
ISSN: 0268-6902

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Article
Publication date: 19 April 2022

Seung Uk Choi, Kun Chang Lee and Hyung Jong Na

The paper aims to estimate abnormal audit fees more precisely than the traditional audit fee model by applying an artificial intelligence (AI) method.

586

Abstract

Purpose

The paper aims to estimate abnormal audit fees more precisely than the traditional audit fee model by applying an artificial intelligence (AI) method.

Design/methodology/approach

The AI technique employed in this paper is the deep neural network (DNN) model, which has been successfully applied to a wide variety of decision-making tasks. The authors examine the ability of the classic ordinary least squares (OLS) and the DNN models to describe the effects of abnormal audit fees on accounting quality based on recent research that demonstrates a systematic link between accruals-based earnings management and abnormal audit fees. Thus, the authors seek to imply that their new method provides a more precise estimate of abnormal audit fees.

Findings

The findings indicate that abnormal audit fees projected using the DNN model are substantially more accurate than those estimated using the classic OLS model in terms of their association with earnings management. Specifically, when abnormal audit fees predicted using the DNN rather than the OLS are incorporated in the accruals-based earnings management model, the adjusted R2s are larger. Additionally, the DNN-estimated coefficient of abnormal audit fees is more favorably associated to earnings management than the classic OLS-estimated coefficient. Additionally, the authors demonstrate that the DNN outperforms OLS in terms of explanatory power in a negative discretionary accruals subsample and a Big 4 auditor subsample. Finally, abnormal audit fees projected using the DNN method provide a better explanation for audit hours than those estimated using the OLS model.

Originality/value

This is the first approach that utilized a machine learning technology to estimate abnormal audit fees. Because more precise measurement yields more credible research results, the findings of this study imply a significant advancement in calculating unusually higher audit fees.

Details

Management Decision, vol. 60 no. 12
Type: Research Article
ISSN: 0025-1747

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Article
Publication date: 14 February 2019

Taegoo Terry Kim, Osman M. Karatepe and Ung Young Chung

The purpose of this study is to propose a research model in which political skill (PS) exerts a direct effect on role stress, job tension, work engagement and service performance…

993

Abstract

Purpose

The purpose of this study is to propose a research model in which political skill (PS) exerts a direct effect on role stress, job tension, work engagement and service performance and buffers the deleterious impact of role stress on job tension. The model also investigates the interrelationships of role stress, job tension, work engagement and service performance.

Design/methodology/approach

The sample was drawn from 261 customer-contact employees in 15 casual restaurants in South Korea. Structural equation modeling was used to assess the aforementioned relationships.

Findings

The findings illustrate that PS alleviates role stress and job tension, while it fosters work engagement and service performance. PS is a panacea to the deleterious impact of role stress on job tension. As expected, role stress heightens job tension, while job tension mitigates work engagement. The findings further reveal that work engagement exerts a positive impact on service performance.

Practical implications

Training interventions can be used to develop employees’ PS. Management should hire the individuals with high PS because such employees can work in harmony with the organizational culture and experience lower role stress and job tension.

Originality/value

The extant hospitality research implicitly demonstrates that very little is known about the outcomes of PS and its moderating role on the relationship between role stress and job tension. The current work set out to fill in this gap.

Details

International Journal of Contemporary Hospitality Management, vol. 31 no. 3
Type: Research Article
ISSN: 0959-6119

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Article
Publication date: 25 September 2018

Bilquis Bibi Safoorah Mohamodhosen, Frederic Gillon, Mounaim Tounzi and Loïc Chevallier

The purpose of this paper is to propose a methodology to seek the optimal topology of electromagnetic devices using the density method while taking into account the non-linear…

133

Abstract

Purpose

The purpose of this paper is to propose a methodology to seek the optimal topology of electromagnetic devices using the density method while taking into account the non-linear behaviour of ferromagnetic materials. The tools and methods used are detailed and applied to a three-dimensional (3D) electromagnet for analysis and validation. Resulting topologies with and without the non-linear behaviour are investigated.

Design/methodology/approach

The polynomial mapping is used with the density method for material distribution in the optimisation domain. To consider the non-linear behaviour of the materials, an analytical approximation based on the Marrocco equation is used and combined with the polynomial mapping to solve the problem. Furthermore, to prevent the occurrence of intermediate materials, a weighted sum of objectives is used in the optimisation problem to eliminate these undesired materials.

Findings

Taking into account the non-linear materials behaviour and 3D model during topology optimisation (TO) is important, as it produces more physically feasible and coherent results. Moreover, the use of a weighted sum of objectives to eliminate intermediate materials increases the number of evaluations to reach the final solution, but it is efficient.

Practical implications

Considering non-linear materials behaviour yields results closer to reality, and physical feasibility of structures is more obvious in absence of intermediate materials.

Originality/value

This work tackles an obstacle of TO in electromagnetism which is often overlooked in literature, that is, non-linear behaviour of ferromagnetic materials by proposing a methodology.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 37 no. 6
Type: Research Article
ISSN: 0332-1649

Keywords

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