Kang-Jia Wang and Jing-Hua Liu
As a powerful mathematical analysis tool, the local fractional calculus has attracted wide attention in the field of fractal circuits. The purpose of this paper is to derive a new
Abstract
Purpose
As a powerful mathematical analysis tool, the local fractional calculus has attracted wide attention in the field of fractal circuits. The purpose of this paper is to derive a new
Design/methodology/approach
A new
Findings
The characteristics of the
Originality/value
To the best of the authors’ knowledge, this paper, for the first time ever, proposes the
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Kang-Jia Wang, Guo-Dong Wang and Feng Shi
The fractal and fractional calculus have obtained considerable attention in the electrical and electronic engineering since they can model many complex phenomena that the…
Abstract
Purpose
The fractal and fractional calculus have obtained considerable attention in the electrical and electronic engineering since they can model many complex phenomena that the traditional integer-order calculus cannot. The purpose of this paper is to develop a new fractional pulse narrowing nonlinear transmission lines model within the local fractional calculus for the first time and derive a novel method, namely, the direct mapping method, to seek for the nondifferentiable (ND) exact solutions.
Design/methodology/approach
By defining some special functions via the Mittag–Leffler function on the Cantor sets, a novel approach, namely, the direct mapping method is derived via constructing a group of the nonlinear local fractional ordinary differential equations. With the aid of the direct mapping method, four groups of the ND exact solutions are obtained in just one step. The dynamic behaviors of the ND exact solutions on the Cantor sets are also described through the 3D graphical illustration.
Findings
It is found that the proposed method is simple but effective and can construct four sets of the ND exact solutions in just one step. In addition, one of the ND exact solutions becomes the exact solution of the classic pulse narrowing nonlinear transmission lines model for the special case 9 = 1, which strongly proves the correctness and effectiveness of the method. The ideas in the paper can be used to study the other fractal partial differential equations (PDEs) within the local fractional derivative (LFD) arising in electrical and electronic engineering.
Originality/value
The fractional pulse narrowing nonlinear transmission lines model within the LFD is proposed for the first time in this paper. The proposed method in the work can be used to study the other fractal PDEs arising in electrical and electronic engineering. The findings in this work are expected to shed a light on the study of the fractal PDEs arising in electrical and electronic engineering.
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The purpose of this paper is to derive a new fractal active low-pass filter (LPF) within the local fractional derivative (LFD) calculus on the Cantor set (CS).
Abstract
Purpose
The purpose of this paper is to derive a new fractal active low-pass filter (LPF) within the local fractional derivative (LFD) calculus on the Cantor set (CS).
Design/methodology/approach
To the best of the author’s knowledge, a new fractal active LPF within the LFD on the CS is proposed for the first time in this work. By defining the nondifferentiable (ND) lumped elements on the fractal set, the author successfully extracted its ND transfer function by applying the local fractional Laplace transform. The properties of the ND transfer function on the CS are elaborated in detail.
Findings
The comparative results between the fractal active LPF (for γ = ln2/ln3) and the classic one (for γ = 1) on the amplitude–frequency and phase–frequency characteristics show that the proposed method is correct and effective, and is expected to shed light on the theory study of the fractal electrical systems.
Originality/value
To the best of the author’s knowledge, the fractal active LPF within the LFD calculus on the CS is proposed for the first time in this study. The proposed method can be used to study the other problems in the fractal electrical systems, and is expected to shed a light on the theory study of the fractal electrical systems.
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The purpose of this paper is to study the new (3 + 1)-dimensional integrable fourth-order nonlinear equation which is used to model the shallow water waves.
Abstract
Purpose
The purpose of this paper is to study the new (3 + 1)-dimensional integrable fourth-order nonlinear equation which is used to model the shallow water waves.
Design/methodology/approach
By means of the Cole–Hopf transform, the bilinear form of the studied equation is extracted. Then the ansatz function method combined with the symbolic computation is implemented to construct the breather, multiwave and the interaction wave solutions. In addition, the subequation method tis also used to search for the diverse travelling wave solutions.
Findings
The breather, multiwave and the interaction wave solutions and other wave solutions like the singular periodic wave structure and dark wave structure are obtained. To the author’s knowledge, the solutions obtained are all new and have never been reported before.
Originality/value
The solutions obtained in this work have never appeared in other literature and can be regarded as an extension of the solutions for the new (3 + 1)-dimensional integrable fourth-order nonlinear equation.
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Ncamsile Ashley Nkambule, Wei-Kang Wang, Irene Wei Kiong Ting and Wen-Min Lu
The main purpose of this study is to empirically investigate the impact of intellectual capital efficiency on US multinational software companies' performance from 2012 to 2016 by…
Abstract
Purpose
The main purpose of this study is to empirically investigate the impact of intellectual capital efficiency on US multinational software companies' performance from 2012 to 2016 by applying data envelopment analysis (DEA).
Design/methodology/approach
It adopts a new slacks-based measure (SBM) to obtain a more accurate performance estimation and rank between companies. Regression analysis is used to test the overall IC and each of its elements (Human Capital, Innovation Capital, Process Capital and Customer Capital).
Findings
The univariate result shows that multinational companies are more efficient than non-multinational companies. However, the regression result shows that multinationality can hardly explain the firm efficiency of software firms. Another interesting finding is that intellectual capital has a positive and significant impact on software firm performance in the US human capital influences firm efficiency directly. However, when human capital is combined with the other elements of IC, the contribution of human capital becomes less significant. This is because people may think that innovation capital, process capital and customer capital can replace human capital, but it is not. In short, human capital may affect firm efficiency through other elements of IC (innovation capital, process capital and customer capital) as it is the base of other elements.
Research limitations/implications
The results show that multinational companies have higher efficiency scores than non-multinational companies. In addition, Intellectual capital has a positive and significant impact on software firm performance in the US human capital influences firm efficiency directly. However, when human capital is combined with the other elements of IC, the contribution of human capital becomes less significant. This is because people may think that innovation capital, process capital and customer capital can replace human capital, but it is not. In short, human capital may affect firm efficiency through other elements of IC (innovation capital, process capital and customer capital) as it is the base of other elements.
Practical implications
Overall, the study highlights the needs of having intellectual capital and its elements (Human Capital, Innovation Capital, Process Capital and Customer Capital) to increase firm efficiency.
Originality/value
First, the authors use a more comprehensive elements of IC, which are human capital, innovation capital, process capital and customer capital for a better IC measurement. Second, this study makes the first attempt using the DSBM model via DEA to examine the operating efficiency of US multinational software firms.
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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…
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.
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Jie Wu, Kang Wang, Ming Zhang, Leilei Guo, Yongpeng Shen, Mingjie Wang, Jitao Zhang and Vaclav Snasel
When solving the cogging torque of complex electromagnetic structures, such as consequent pole hybrid excitation synchronous (CPHES) machine, traditional methods have a huge…
Abstract
Purpose
When solving the cogging torque of complex electromagnetic structures, such as consequent pole hybrid excitation synchronous (CPHES) machine, traditional methods have a huge computational complexity. The notable feature of CPHES machine is the symmetric range of field-strengthening and field-weakening, but this type of machine is destined to be equipped with a complex electromagnetic structure. The purpose of this paper is to propose a hybrid analysis method to quickly and accurately solve the cogging torque of complex 3D electromagnetic structure, which is applicable to CPHES machine with different magnetic pole shapings.
Design/methodology/approach
In this paper, a hybrid method for calculating the cogging torque of CPHES machine is proposed, which considers three commonly used pole shapings. Firstly, through magnetic field analysis, the complex 3D finite element analysis (FEA) is simplified to 2D field computing. Secondly, the discretization method is used to obtain the distribution of permeance and permeance differential along the circumference of the air-gap, taking into account the effect of slots. Finally, the cogging torque of the whole motor is obtained by using the idea of modular calculation and the symmetry of the rotor structure.
Findings
This method is applicable to different pole shapings. The experimental results show that the proposed method is consistent with 3D FEA and experimental measured results, and the average calculation time is reduced from 8 h to 4 min.
Originality/value
This paper proposes a new concept for calculating cogging torque, which is a hybrid calculation of dimension reduction and discretization modules. Based on magnetic field analysis, the 3D problem is simplified into a 2D issue, reducing computational complexity. Based on the symmetry of the machine structure, a modeling method for discretized analytical models is proposed to calculate the cogging torque of the machine.
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Wei-Kang Wang, Wen-Min Lu, Irene Wei Kiong Ting and Wun-Ya Siao
This study aims to examine the relationships among International Financial Reporting Standards (IFRS) adoption, earnings management, and corporate efficiency.
Abstract
Purpose
This study aims to examine the relationships among International Financial Reporting Standards (IFRS) adoption, earnings management, and corporate efficiency.
Design/methodology/approach
First, the authors employ the epsilon-based measure (EBM) of the data envelopment analysis to measure the corporate performance of the Taiwanese electronics industry from 2011 to 2014. Second, the authors regress the IFRS adoption and earnings management on corporate efficiency.
Findings
The findings show that the corporate efficiency deteriorated after IFRS adoption. Although the regression analysis shows that the relationship between earnings management and corporate efficiency is significantly positive, the authors find that IFRS adoption is effective in unveiling earnings management. Moreover, IFRS adoption moderates the impact earnings management and corporate efficiency.
Research limitations/implications
This study provides reference for decision-makers in the application of accounting principles and in the understanding of the IFRS impact adoption.
Practical implications
IFRS adoption can either facilitate or limit the earnings management that would affect corporate efficiency significantly and help the electronics industry as well as investors to know the changes in accounting principles and their effects on corporate efficiency.
Originality/value
The authors use the EBM of efficiency model to measure corporate efficiency and employ the modified Jones model to measure earnings management.
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Jinghua Xu, Mingzhe Tao, Mingyu Gao, Shuyou Zhang, Jianrong Tan, Jingxuan Xu and Kang Wang
The coupling impact of hybrid uncertain errors on the machine precision is complex, as a result of which the designing method with multiple independent error sources under…
Abstract
Purpose
The coupling impact of hybrid uncertain errors on the machine precision is complex, as a result of which the designing method with multiple independent error sources under uncertainties remains a challenge. For the purpose of precision improvement, this paper focuses on the robot design and aims to present an assembly precision design method based on uncertain hybrid tolerance allocation (UHTA), to improve the positioning precision of the mechanized robot, as well as realize high precision positioning within the workspace.
Design/methodology/approach
The fundamentals of the parallel mechanism are introduced first to implement concept design of a 3-R(4S) &3-SS parallel robot. The kinematic modeling of the robot is carried out, and the performance indexes of the robot are calculated via Jacobian matrix, on the basis of which, the 3D spatial overall workspace can be quantified and visualized, under the constraints of limited rod, to avoid the singular position. The error of the robot is described, and a probabilistic error model is hereby developed to classify the hybrid error sensitivity of each independent uncertain error source by Monte Carlo stochastic method. Most innovatively, a methodology called UHTA is proposed to optimize the robot precision, and the tolerance allocation approach is conducted to reduce the overall error amplitude and improve the robotized positioning precision, on the premise of not increasing assembly cost.
Findings
The proposed approach is validated by digital simulation of medical puncture robot. The experiment highlights the mathematical findings that the horizontal plane positioning error of the parallel robotic mechanism can be effectively reduced after using UHTA, and the average precision can be improved by up to 39.54%.
Originality/value
The originality lies in UHTA-based precision design method for parallel robots. The proposed method has widely expanding application scenarios in industrial robots, biomedical robots and other assembly automation fields.
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Jane L.J. Hao, Vivian W.Y. Tam, H.P. Yuan, J.Y. Wang and J.R. Li
The aim of this paper is to develop a model based on system dynamics (SD) approach, which integrates three subsystems for simulating construction and demolition (C&D) waste…
Abstract
Purpose
The aim of this paper is to develop a model based on system dynamics (SD) approach, which integrates three subsystems for simulating construction and demolition (C&D) waste management in Shenzhen, Mainland China.
Design/methodology/approach
SD approach was first used to construct the model for C&D waste management in Shenzhen. The model was then converted for running on computer through the software package “iThink”, which was specifically designed for SD modeling. The data required for model simulation was derived through various ways, including literature review, examination of official reports and yearbooks, and questionnaires. After all the parameters in the model were determined, simulation was carried out.
Findings
The model proposed in this research can provide an experimental simulation platform to investigate the complexity and interdependencies of factors in managing C&D waste in Shenzhen, Mainland China. The simulation results show that the pressing situation of C&D waste management in Shenzhen would aggravate if no effective measures were taken to address it during the simulation period. Participants' active participation and cost consideration are the two major factors affecting C&D waste reduction. Furthermore, new landfills should be planned to properly handle the C&D waste accumulated in Shenzhen over the past few years.
Originality/value
Although some studies have been conducted under the topic of C&D waste management during the past few years in Shenzhen – how to effectively and efficiently handle the waste is still unsolved. Factors affecting the effectiveness of C&D waste management have separately been examined in the previous studies, without considering their interrelations. The SD‐based model is developed in this research to investigate the complex and interdependent relationships among these factors. The model can deepen participants' understandings about C&D waste management and help explore the major factors affecting the effectiveness of management activities. The measures, which are proposed based on the simulation results, can serve as a valuable reference for planning C&D waste management in Shenzhen.