bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of ethical context and Machiavellianism on attitudes toward earnings management in China
Authors: Shafer William E. , Wang Zhihong 
Published: June 2011

PurposeThe purpose of this study is to investigate the effects of Chinese industry accountants' perceptions of the ethical context in their organization and Machiavellianism on attitudes toward earnings management.Design/methodology/approachThe research is based on a survey of professional accountants employed by companies in Mainland China.FindingsThe results indicate that perceptions of a strong organizational emphasis on serving the public interest (benevolent/cosmopolitan climate) significantly reduced professional accountants' willingness to condone accounting earnings management. Professionally certified accountants also judged accounting earnings management more harshly. Consistent with our expectations, high Machiavellians judged earnings management more leniently, although this effect was only marginally significant in the case of accounting earnings management. In contrast to prior studies of earnings management in the USA, the participants judged accounting earnings management more leniently, but judged operating earnings management more harshly.Originality/valueThis is the first study to document that an organizational emphasis on serving the public interest can restrain aggressive behavior among industry accountants. Claims of serving the public interest in accounting have traditionally focused on the role of the independent auditor in protecting the public from misleading financial reporting. The results indicate that appeals to public interest obligations also have resonance for professional accountants in industry. The fact that certified accountants were less tolerant of accounting earnings management also has important implications, demonstrating the practical value of professional certification programs and their associated training and socialization processes. The contrast observed between the ethical judgments of our Chinese participants and US accountants surveyed in previous studies raises important questions for further research.
Agency theory and managerial ownership: evidence from Malaysia
Authors: Mustapha Mazlina , Che Ahmad Ayoib 
Published: June 2011

PurposeThe purpose of this paper is to investigate the effect of managerial ownership in relation to agency theory in the Malaysian business environment. In addition to examining the total managerial shareholdings, this study also investigates the association between direct and indirect managerial shareholdings with agency costs.Design/methodology/approachThe data for the study is obtained from two sources, namely primary (questionnaire) and secondary (annual reports) data. The sample companies are 235 companies listed on Bursa Malaysia for the financial year ended 2006. Multiple regression analysis is used to estimate the relationship between the variables.FindingsThe results of the study indicate that managerial ownership in various segments has an inverse relationship with total monitoring costs as predicted in agency theory. This finding is consistent with earlier studies in western countries and supports the convergence of interest hypothesis.Originality/valueThis study gives a unique contribution to corporate governance studies relating to the effect of ownership structure in relation to agency theory in Malaysian companies, one of the countries in Asia. Previous studies claimed that it is unknown whether the agency theory findings in western countries have equal impact in Asian organizations. Previous literature also indicates that there is a possibility that given the cultural differences, the typical nature of agents in agency theory may not be the case with regard to non‐western countries. Thus, this study provides evidence that support prior research findings in western countries relating to the effect of managerial ownership on the agency relationship which is reflected in its agency costs.
Audit quality and accrual persistence: evidence from the pre‐ and post‐Sarbanes‐Oxley periods
Authors: Chambers Dennis , Payne Jeff 
Published: June 2011

PurposeThe purpose of this paper is two‐fold: first, to examine whether the quality of accruals, as measured by accrual persistence, improved in the post‐Sarbanes‐Oxley (SOX) period, and second, to examine the degree to which SOX‐related improvement in accrual persistence varies across companies depending on the degree of their auditor's independence.Design/methodology/approachThe paper compares accrual persistence in the pre‐ and post‐SOX periods to test the first question. Then, partitioning on relative client importance as a measure of auditor independence, the paper compares the SOX‐based improvement for clients of low and high independence audit firms.FindingsThe study first demonstrates that accrual persistence increased significantly in the post‐SOX period. The study also finds evidence that in the post‐SOX period, the subsample of companies audited by Big‐N auditors with lower‐independence experienced the greatest improvement in accrual persistence.Originality/valueThis is the first paper to evaluate SOX‐related improvements in the quality of earnings as measured by accrual persistence. Prior studies test abnormal accruals and other earnings management metrics, however, persistence is a more general test of financial statement quality. This study also is the first to compare SOX‐related improvements for clients of firms with differing levels of independence.
Finite element analysis of transient electromagnetic‐thermal phenomena in a squirrel cage motor
Authors: Baranski Mariusz , Demenko Andrzej , Lyskawinski Wieslaw , Szelag Wojciech 
Published: June 2011

PurposeThe purpose of this paper is to elaborate the method and algorithm for the analysis of electromagnetic and thermal transients in a squirrel cage induction motor.Design/methodology/approachThe paper presents the special software for transient finite element (FE) analysis of coupled electromagnetic‐thermal problems in a squirrel cage induction motor. The software has been prepared and is successfully applied in the design of special squirrel cage motors, e.g. the motors working in cryogenic conditions. A time‐stepping FE method and transients analysis of an induction motor has been applied. The nonlinearity of the magnetic circuit, the movement of the rotor and the skewed slots have been taken into account. The results of computations have been compared with measurements.FindingsThe method presented and the elaborated specialised software for FE analysis of electromagnetic and thermal transients are used to determine the dynamic performance of the squirrel‐cage induction motor. The results of simulations compared with measurements confirm the adequacy of this approach to the analysis of coupled electromagnetic‐thermal problems.Research limitations/implications3D effects have only been taken into account by quasi‐3D techniques (e.g. the multi‐slice for the skewed rotor slots).Practical implicationsThe software developed can be useful in the analysis and design of squirrel cage motor, especially motors working in cryogenic conditions.Originality/valueThe paper offers appropriate software for transient analysis of coupled electromagnetic and thermal problems in squirrel cage motors with skewed slots.
Step response optimization method of switched reluctance motor
Authors: Stępień Sławomir , Bernat Jakub 
Published: June 2011

PurposeThe purpose of this paper is to present a method of modeling the variable reluctance stepper motor using the time‐stepping finite element technique. The proposed model is used to minimize the step response overshoots considering the stator and rotor tooth geometry.Design/methodology/approachA strongly coupled field‐circuit model considering magnetic nonlinearity of the stepper motor is presented. As the main contribution, the Nelder‐Mead method of the motor geometry optimization that minimize the step response overshoots and positioning error is proposed.FindingsThe proposed method can be applied to obtain the optimal tooth/pole geometry of the stepper motor which is efficient to perform the possibly accurate positioning.Originality/valueThe paper examines the application of the presented optimization method to minimize the positioning error of the four‐phased variable reluctance stepper motor.
Sliding mode control of a permanent magnet direct drive under non‐linear friction
Authors: Brock Stefan 
Published: June 2011

PurposeThe purpose of this paper is to find a simple structure of motion controller for permanent magnet direct drive. Application of sliding mode controller theory and equivalent disturbance estimator creates proper non‐linear characteristics, which ensures controller robustness against friction.Design/methodology/approachThe position and speed controller is based on robust design methodology introduced by a sliding mode technique. The paper proposes a combination of sliding mode controller and proportional integral (PI) equivalent disturbance estimator. The friction model is Coulomb friction with a large static friction effect. The double boundary layer is used to compensate the effect of stiction. The synthesis is performed using simulation techniques and subsequently the behaviour of a laboratory speed control system is validated in the experimental setup. The control algorithms of the system are performed by a microprocessor floating point DSP control system.FindingsThe proposed sliding mode controller structure with equivalent disturbance estimator guarantees expected robustness against friction. Experimental results show that the control approach can decrease the tracking error, enhance the system's robustness and attenuate high‐frequency chattering in the control signal.Research limitations/implicationsThe proposed controller was tested on a single machine under well‐defined conditions. Further investigations are required before any industrial applications.Practical implicationsThe proposed controller synthesis and its results may be very helpful in robotic systems where non‐linear friction is a characteristic for many industrial robots and manipulators.Originality/valueThe method of sliding mode controller synthesis was proposed and validated by simulation and experimental investigations.
Modification of Park variable transformation for wye‐connected winding without neutral wire
Authors: Burlikowski Wojciech 
Published: June 2011

PurposeThe purpose of this paper is to present a modification of the Park variable transformation for a three‐phase wye‐connected winding without neutral wire. A new physical interpretation of the winding equivalent circuit is proposed.Design/methodology/approachAn equivalent circuit representing reluctance motor stator winding is rearranged to enable easier physical interpretation of obtained voltage equation. The Park transformation and constraints resulting from Kirchhof's laws are then applied to obtain a two‐axis mathematical model of the motor.FindingsA new physical two‐phase interpretation of the voltage equation for a three‐phase wye‐connected winding without neutral wire is proposed. A novel two‐axis transformation is formulated for all variables. Compared to the Park transformation, which is the same for all variables, in the proposed transformation its matrices for currents and voltages/flux linkages are different, yet strongly interconnected.Research limitations/implicationsThe proposed transformation is formulated for a specific type of winding connection scheme. Therefore, it is limited in its application.Practical implicationsFrom the practical point of view, the proposed transformation could be very useful as it applies to the most popular stator winding connection scheme. Its main advantages are fewer number of trigonometric parameters in the matrices and measurability of all currents and voltages present in its voltage equations. It could be of special importance for electric machines with non‐sinusoidal field distribution (e.g. Brushless DC).Originality/valueThe paper presents a new type of variable transformation for three‐phase electric machines with wye‐connected windings without neutral wire. Proposed transformation combines different transformations for currents and voltages/flux linkages.
Computational cost‐effective modelling of non‐linear characteristics in permanent magnet synchronous motors
Authors: Franck David , Hafner Martin , Hameyer Kay 
Published: June 2011

PurposeIn the optimisation of electrical drives, the required degree of detail in the simulation increases constantly. Especially, the industrial demand on multi‐objective optimisation craves for highly efficient models. The purpose of this paper is to propose a hybrid model for the computation of the air‐gap field of a permanent magnet synchronous motor (PMSM) combining analytic and numeric methods.Design/methodology/approachThe classic conformal mapping (CM) approach is improved by the numeric approximation of the required ansatz‐functions. This approach allows to consider the non‐linear permeability of the applied materials and complex geometries. The non‐linear permeance‐function is described by a one‐dimensional wave varying in time and space.FindingsThe permeance‐function has to be derived for different load cases at the actual stage.Research limitations/implicationsA physical motivated modelling allowing for an appropriate interpolation between different load cases is planned in further research.Practical implicationsThe proposed approach is applied to a surface mounted PMSM. It is validated by means of a non‐linear finite element analysis.Originality/valueThe hybrid model offers to consider rotors with buried magnets using the CM approach. It is possible to either use analytic or numeric modelling of rotor ansatz‐function, stator current ansatz‐function and permeance‐function with the proposed approach. Non‐linear permeability of iron is modelled by means of a wave representation of the permeance‐function. This can significantly reduce the computational cost in the design and optimisation stage of electrical machines.
Interactive visualization of transient 3D electromagnetic and n‐dimensional parameter spaces in virtual reality
Authors: Hafner Martin , Böhmer Stefan , Henrotte François , Hameyer Kay 
Published: June 2011

PurposeNowadays many parameter studies for the design and optimization of electromagnetic devices are carried out by means of 2D and 3D nonlinear finite element (FE) models. Through optimization algorithms selecting one design as optimal with respect to the chosen cost function, the user does not gain any intuitive clue of the interrelations existing between design parameters, although numerous computations have been performed across the whole parameter space of the system. The purpose of this paper is to visualize a complex nonlinear FE solution system, which is parameterized through a number of control variables, in virtual reality (VR).Design/methodology/approachThis paper presents a visualization approach for n‐dimensional parameter spaces of FE solutions in VR and the corresponding interpolation methods for enabling navigation through it.FindingsThe solution of an arbitrary electromagnetic FE problem is categorized with respect to possible changes, due to chosen design parameters, within the solution itself and variations in the underlying mesh in order to find appropriate interpolation methods for the visualization of each type of parameter space.Practical implicationsThe implementation is based on modifying the popular Visualization Toolkit (VTK).Originality/valueThe paper presents different solution approaches for the visualization of an interpolation between arbitrary different meshes, but the problem remains unsolved and requires further research.
Accounting for saturation in conformal mapping modeling of a permanent magnet synchronous machine
Authors: Hafner Martin , Franck David , Hameyer Kay 
Published: June 2011

PurposeIn the electromagnetic field simulation of modern servo drives, the computation of higher time and space harmonics is essential to consider appearing torque pulsations, radial forces and ripple torques. The purpose of this paper is to propose a method to cover the effect of saturation on the armature flux density within conformal mapping (CM) by an finite element (FE) re‐parameterization.Design/methodology/approachField computation by CM techniques is a time‐effective method to compute the radial and tangential field components, but it generally neglects the effect of saturation.FindingsThis paper presents a method to re‐parameterize the CM approach by single FE computations so as to consider saturation in the model over a wide operation range of the electrical drive.Practical implicationsThe proposed method is applied to a surface permanent magnet synchronous machine, and compared to numerical results obtained by finite element analysis (FEA).Originality/valueThe paper shows that an accuracy similar to that of FE simulations can be obtained with still the low‐computation time that is the characteristic of analytical models.
Field‐circuit simulation of the dynamics of the outer rotor permanent magnet brushless DC motor
Authors: Knypiński Łukasz , Nowak Lech 
Published: June 2011

PurposeThe purpose of this paper is to elaborate a mathematical model of dynamic operation of the permanent magnet brushless DC (BLDC) motor with outer rotor and investigate the influence of magnets width on the dynamic parameters.Design/methodology/approachThe mathematical model of the devices includes: the equation of the electromagnetic field, the electric circuit equations and equation of mechanical motion. In elaborated algorithm, all these equations are coupled – therefore they are solved simultaneously. The numerical implementation is based on finite element method and step‐by‐step algorithm. The non‐linear‐coupled field‐circuit equations have been solved by using the Newton‐Raphson algorithm. The computer code for dynamics simulation of the machine has been developed.FindingsThe elaborated algorithm and the computer code have been applied for the 2D simulation of BLDC motor dynamics. The algorithm has a good convergence and its usefulness was proved. Various results of the analysis are presented and discussed.Originality/valueThe presented approach and computer code can be successfully applied to the design and optimization of different structure of the BLDC motors.
Computer analysis of high‐speed PM BLDC motor properties
Authors: Krykowski Krzysztof , Hetmańczyk Janusz , Gałuszkiewicz Zbigniew , Miksiewicz Roman 
Published: June 2011

PurposeThe purpose of this paper is to elaborate a method of computer analysis of high‐speed motor with specific parameters and verifying the obtained results, i.e. computer models by experimental (laboratory) tests.Design/methodology/approachIn order to determine motor properties from the viewpoint of energy conversion, a model using FEM was worked out with the help of Maxwell software. To determine static and dynamic properties of both motor and drive, Matlab/Simulink models were used; one of these models was a built‐in (library) model, the other one was proposed by the authors.FindingsThe new analysis method and model of high‐speed motor have been carried out.Research limitations/implicationsThe permanent magnet brushless direct current high‐speed motor was the subject of the research. In the first part of the research, the properties of the motor were determined by using finite element method.Practical implicationsThe laboratory prototype can be a starting point in establishing the production of the high‐speed motors with rotational speed in the range of 50,000‐100,000 rpm.Social implicationsAt this moment, there are several possible application of the high‐speed motor and it should be expected that other new applications can appear in near future after the start of the production.Originality/valueThe paper shows that the computer‐based analysis method determines the motor properties accurately. It is also pointed out that a motor with half‐open slots has advantageous properties. The new simulation model of high‐speed motor has been carried out. This model allows taking into account some imperfections caused by slots and rectangular cross‐section magnets.
Modelling of rotational magnetization in anisotropic sheets
Authors: Mazgaj Witold 
Published: June 2011

PurposeThe aim of this paper is to present a new relatively simple model of the rotational magnetization process in anisotropic sheets.Design/methodology/approachThe surface of a sample of an anisotropic sheet is divided into an assumed number of specified directions. To each direction a certain hysteresis loop, the so‐called direction hysteresis, is assigned. The parameters of the proposed model are calculated on the basis of such values as the saturation flux density, the residual flux density (remanence), and the coercive force. It is also necessary to take into account the anisotropy constant and also the distribution function of the grains in the sample of the given anisotropic material.FindingsThe model of the rotational magnetization process of soft ferromagnetic materials takes into account two fundamental phenomena: the irreversible domain wall movements and the rotations of the flux density vectors from the easy magnetization axes. This model can also be used for the modelling of the axial magnetization process.Practical implicationsThe proposed model can be used in numerical calculations of the rotational magnetization in magnetic circuits of electrical machines for any work conditions. However, for the comprehensive calculation of the magnetic field distribution this model should be completed with eddy current equations. Eddy currents influence magnetic field distribution in electric steel sheets.Originality/valueA new model of the rotational magnetization process in anisotropic sheets is proposed.
Performance analysis of the sliding‐mode speed observer with magnetizing reactance estimation for the sensorless induction motor drive
Authors: Orlowska‐Kowalska Teresa , Dybkowski Mateusz , Tarchala Grzegorz 
Published: June 2011

PurposeThe purpose of this paper is to obtain an accurate and robust estimation method of the rotor flux and speed for the sensorless induction motor (IM) drive with magnetizing reactance variations.Design/methodology/approachThe sensorless IM drive with sliding mode flux and speed observer (SMO) is presented. Proposed estimation algorithm is extended with the additional magnetizing reactance estimator based on the magnetizing characteristic of the IM. The dynamical and steady‐state properties of the drive system in the low‐speed and in the field‐weakening regions are tested. The simulation results are verified by experimental tests, over the wide range of motor speed and drive parameter changes.FindingsIt is shown that the sensorless induction motor drive can work stable in wide speed range using the Sliding‐Mode Observer with additional magnetizing reactance estimator.Research limitations/implicationsThe investigation looked mainly at the speed estimation methodology with additional motor parameter estimator.Practical implicationsThe proposed SMO can be easily implemented on digital signal processors. The implementation was tested in an experimental setup with DS1103 card. The fixed‐point realisation needs to be developed to obtain the practical application in the industrial drive systems.Originality/valueThe SMO with an additional magnetizing reactance estimator based on magnetizing characteristic of the IM is tested. This method of the speed and flux reconstruction can be applied in different electrical drives working in wide speed range, including very low‐speed region and field‐weakening region, too. The proposed solution is not sensitive to magnetizing reactance variations and is simple in practical implementation in the real‐time system.