bluuebunny/crossref_metadata_2025_split huggingface dataset:
Discrete optimal control for robot manipulators
Authors: Mehdi Fateh Mohammad , Baluchzadeh Maryam 
Published: February 2014

Purpose
– Applying discrete linear optimal control to robot manipulators faces two challenging problems, namely nonlinearity and uncertainty. This paper aims to overcome nonlinearity and uncertainty to design the discrete optimal control for electrically driven robot manipulators.

Design/methodology/approach
– Two novel discrete optimal control approaches are presented. In the first approach, a control-oriented model is applied for the discrete linear quadratic control while modeling error is estimated and compensated by a robust time-delay controller. Instead of the torque control strategy, the voltage control strategy is used for obtaining an optimal control that is free from the manipulator dynamics. In the second approach, a discrete optimal controller is designed by using a particle swarm optimization algorithm.

Findings
– The first controller can overcome uncertainties, guarantee stability and provide a good tracking performance by using an online optimal algorithm whereas the second controller is an off-line optimal algorithm. The first control approach is verified by stability analysis. A comparison through simulations on a three-link electrically driven robot manipulator shows superiority of the first approach over the second approach. Another comparison shows that the first approach is superior to a bounded torque control approach in the presence of uncertainties.

Originality/value
– The originality of this paper is to present two novel optimal control approaches for tracking control of electrically driven robot manipulators with considering the actuator dynamics. The novelty is that the proposed control approaches are free from the robot's model by using the voltage control strategy. The first approach is a novel discrete linear quadratic control design supported by a time-delay uncertainty compensator. The second approach is an off-line optimal design by using the particle swarm optimization.
Analysis of a circular microstrip antenna on isotropic or uniaxially anisotropic substrate using neurospectral approach
Authors: Bedra Sami , Benkouda Siham , Fortaki Tarek 
Published: February 2014

Purpose
– The paper aims to propose an artificial neural network (ANN) in conjunction with spectral domain formulation for fast and accurate determination of the resonant frequency and quality factor of circular microstrip antenna printed on isotropic or anisotropic substrate. This neurospectral approach reduces the problem complexity.

Design/methodology/approach
– The moment method implemented in the spectral domain provides good accuracy but its computational cost is high due to the evaluation of the slowly decaying integrals and the iterative nature of the solution process. The paper introduces the electromagnetic knowledge combined with ANN in the analysis of circular microstrip antenna on isotropic or uniaxially anisotropic substrate to reduce the complexity of the spectral approach and to minimize the CPU time necessary to obtain the numerical results.

Findings
– The resonant frequency results obtained from the neural model are in very good agreement with the experimental and theoretical results available in the literature. Finally, numerical results for the substrate anisotropy effect on the resonant frequency, quality factor and radiation pattern are also presented.

Originality/value
– The paper develops fast and accurate model based on ANN technique to calculate the resonant frequencies and quality factors of circular microstrip antennas. ANN is used to model the relationship between the parameters of the microstrip antenna and the resonant frequencies and quality factors obtained from the spectral domain approach. This relatively simple model allows designers to predict accurately the resonant frequencies and quality factors for a given design without having to develop or run the spectral method codes themselves. The main advantages of the method are: less computing time than the spectral model, results with accuracy equivalent to that of full-wave models and cost effectiveness, since the client can use a simple PC for implementation. Another advantage of the proposed ANN model is that it takes into account the uniaxial anisotropy in the substrate without increasing the network size. This is done by combining ANN with electromagnetic knowledge.
Accuracy evaluation of three-dimensional FE analysis based on nonconforming voxel element
Authors: Sato Takahiro , Watanabe Kota , Igarashi Hajime 
Published: February 2014

Purpose
– Three-dimensional (3D) mesh generation for shape optimizations needs long computational time. This makes it difficult to perform 3D shape optimizations. The purpose of this paper is to present a new meshing method with light computational cost for 3D shape optimizations.

Design/methodology/approach
– This paper presents a new meshing method on the basis of nonconforming voxel finite element method. The 3D mesh generation is performed with light computational cost keeping the computational accuracy.

Findings
– It is shown that the computational cost for 3D mesh generation can be reduced without deteriorating numerical accuracy in the FE analysis. It is reported the performance of the present method.

Originality/value
– The validity of the nonconforming voxel elements is tested to apply it to the optimization of 3D optimizations.
A novel two-port network model for RCPT system
Authors: Xian Zhang , Qingxin Yang , Haiyan Chen , Xin Zhang , Liang Jin , Yang Li 
Published: February 2014

Purpose
– The purpose of the paper is to show that how a contactless power transmission system via electromagnetic (EM) resonantly coupling power transmission (RCPT) technology may be analyzed in-depth by using a detailed T-type two-port network model with leakage inductance variable.

Design/methodology/approach
– Through the introduction of coupling coefficient and quality factor, the influence of different physical parameters on the system performance is taken into consideration and validated by power transmission experiment.

Findings
– It is shown that system performance is mainly subject to coupling coefficient and quality factor from the two-port network model in this paper. Moreover, there are three working status of dynamic transmission, which are over coupling, critical coupling and under coupling.

Originality/value
– Two-port network model applied to practical RCPT system design considering impedance loss on resonators, etc.
Calculation and validation of iron loss in laminated core of power and distribution transformers
Authors: Wang Xiaoyan , Cheng Zhiguang , Lin Li , Wang Jianmin 
Published: February 2014

Purpose
– The purpose of this paper is to present a simple method to analyze the iron loss in the laminated core of power and distribution transformers.

Design/methodology/approach
– This paper presents a practical method to calculate the no-load loss in the transformer cores. Considering the non-uniformity of the magnetic flux density in the corner areas of the Epstein frames will affect the measurement precision of the Wt-B curves then further affect the core loss calculation in FEM, a dual-Epstein frame method is used to measure the Wt-B curves with the Epstein sample stripes cutting by different angles to the rolling direction. A 2D FEM that considers the type of joints of the core and eddy current effect in the laminations is used to analyze the core loss with multi-angle Wt-B curves.

Findings
– The impact of lamination thickness, size of gaps and type of joint of the core are considered. Considering the no-load testing conditions, harmonics in the exciting currents are taken into account.

Originality/value
– Harmonic wave of magnetic flux density in the transformer core is calculated and the core loss in the joint region is calculated by the loss curve measured with dual-Epstein frame. It makes the calculation result of transformer core loss more exactly.
Time-stepping finite element analysis on the influence of rotational flux on local core losses of AC electrical machines
Authors: Haisen Zhao , Xiaofang Liu , Xueshen Cui , Yingli Luo 
Published: February 2014

Purpose
– The purpose of the paper is to study the influence of rotational flux on local core losses of the motors, which is difficult to distinguish the iron losses caused by rotational flux in certain electric machines through experiment. Therefore, time-stepping finite element method (T-S FEM) is used to consider the rotational flux and to predict the local core losses.

Design/methodology/approach
– Time-stepping finite element method.

Findings
– It is found that, in stator side, rotational flux mainly exists in tooth root and yoke area near the bottom of stator slot, those area is about 45 percent of total stator core area; in rotor side, due to slot harmonic field, the rotational flux mainly exists in the tip of tooth.

Originality/value
– Through analyzing the magnetization characteristics at different positions in stator and rotor cores by T-S FEM, the influence of rotational flux on local core losses of AC electric machines is studied.
An efficient application of PML in fourth-order precise integration time domain method for the numerical solution of Maxwell's equations
Authors: Bai Zhongming , Ma Xikui , Zhuansun Xu , Liu Qi 
Published: February 2014

Purpose
– The purpose of the paper is to introduce a perfectly matched layer (PML) absorber, based on Berenger's split field PML, to the recently proposed low-dispersion precise integration time domain method using a fourth-order accurate finite difference scheme (PITD(4)).

Design/methodology/approach
– The validity and effectiveness of the PITD(4) method with the inclusion of the PML is investigated through a two-dimensional (2-D) point source radiating example.

Findings
– Numerical results indicate that the larger time steps remain unchanged in the procedure of the PITD(4) method with the PML, and meanwhile, the PITD(4) method employing the PML is of the same absorbability as that of the finite-difference time-domain (FDTD) method with the PML. In addition, it is also demonstrated that the later time reflection error of the PITD(4) method employing the PML is much lower than that of the FDTD method with the PML.

Originality/value
– An efficient application of PML in fourth-order precise integration time domain method for the numerical solution of Maxwell's equations.
Finite element modeling and analyzing for lumbar muscle electrical activity
Authors: Yin Ning , Xu Guizhi , Zhang Shuai , Guo Lei 
Published: February 2014

Purpose
– The purpose of the paper is to present a three-dimensional model and analyze the internal link between surface potential distribution and the electrical activity of lumbar muscles with finite element method.

Design/methodology/approach
– Finite element method.

Findings
– The simulated results have shown that there is a significant difference of surface potential topography patterns between low back pain (LBP) patients and normal healthy control. The normal shows symmetrical in contrast with the asymmetrical LBP pattern.

Originality/value
– It provides a new view to analyze lumbar muscle activity with finite element method, which has a potential clinical application on lumbar muscle function analysis and LBP rehabilitation assessment.
Multi-objective optimization approach to reliability-based robust global optimization of electromagnetic device
Authors: Ren Ziyan , Zhang Dianhai , Seop Koh Chang 
Published: February 2014

Purpose
– The purpose of this paper is to propose a multi-objective optimization algorithm, which can improve both the performance robustness and the constraint feasibility when the uncertainty in design variables is considered.

Design/methodology/approach
– Multi-objective robust optimization by gradient index combined with the reliability-based design optimization (RBDO).

Findings
– It is shown that searching for the optimal design of the TEAM problem 22, which can minimize the magnetic stray field by keeping the target system energy (180 MJ) and improve the feasibility of superconductivity constraint (quenching condition), is possible by using the proposed method.

Originality/value
– RBDO method applied to the electromagnetic problem cooperated with the design sensitivity analysis by the finite element method.
Vector magnetic property of electrical steel sheet and its influence on distributions of magnetic field and iron loss for electrical machines
Authors: Yoon Heesung , Seop Koh Chang 
Published: February 2014

Purpose
– The purpose of this paper is to present the vector magnetic properties of the electrical steel sheet and investigate its influences on the magnetic field and iron loss distributions for the electrical machines.

Design/methodology/approach
– The vector magnetic property of the electrical steel sheet is measured by using a two-dimensional single sheet tester and modelled through an E&S vector hysteresis model to be applied to finite element analysis.

Findings
– The magnetic field and iron loss distributions are calculated by finite element analysis combined with the E&S vector hysteresis model for the three-phase transformer and induction motor models.

Originality/value
– The influences of the vector magnetic property on the electrical machines are verified by comparing with the numerical results from a scalar magnetic property.
Unconditionally stable improved meshless methods for electromagnetic time-domain modeling
Authors: Razmjoo Hooman , Movahhedi Masoud 
Published: February 2014

Purpose– In this paper, a modified meshless method, as one of the numerical techniques that has recently emerged in the area of computational electromagnetics, is extended to solving time-domain wave equation. The paper aims to discuss these issues.Design/methodology/approach– In space domain, the fields at the collocation points are expanded into a series of new Shepard's functions which have been suggested recently and are treated with a meshless method procedure. For time discretization of the second-order time-derivative, two finite-difference schemes, i.e. backward difference and Newmark-βtechniques, are proposed.Findings– Both schemes are implicit and always stable and have unconditional stability with different orders of accuracy and numerical dispersion. The unconditional stability of the proposed methods is analytically proven and numerically verified. Moreover, two numerical examples for electromagnetic field computation are also presented to investigate characteristics of the proposed methods.Originality/value– The paper presents two unconditionally stable schemes for meshless methods in time-domain electromagnetic problems.
UWB signal receiver with sub-Nyquist rate sampling based on compressed sensing
Authors: Zhuang Xiaoyan , Zhao Yijiu , Wang Li , Wang Houjun 
Published: February 2014

Purpose
– The purpose of this paper is to present a compressed sensing (CS)-based sampling system for ultra-wide-band (UWB) signal. By exploiting the sparsity of signal, this new sampling system can sub-Nyquist sample a multiband UWB signal, whose unknown frequency support occupies only a small portion of a wide spectrum.

Design/methodology/approach
– A random Rademacher sequence is used to sense the signal in the frequency domain, and a matrix constructed by Hadamard basis is used to compress the signal. The probability of reconstruction is proved mathematically, and the reconstruction matrix is developed in the frequency domain.

Findings
– Simulation results indicate that, with an ultra-low sampling rate, the proposed system can capture and reconstruct sparse multiband UWB signals with high probability. For sparse multiband UWB signals, the proposed system has potential to break through the Shannon theorem.

Originality/value
– Different from the traditional sub-Nyquist techniques, the proposed sampling system not only breaks through the limitation of Shannon theorem but also avoids the barrier of input bandwidth of analog-to-digital converters (ADCs).
Use of comic strips in teaching earthquakes to kindergarten children
Authors: Sharpe Justin , O. Izadkhah Yasamin 
Published: February 2014

Purpose– Up to now, no extensive work has addressed the capacity and resiliency of pre-school children, nor the importance of extending disaster preparedness education to them. The purpose of this paper is to show that given the right learning tools to engage them, in this case a comic strip designed for this purpose by the first author, pre-school children are able to demonstrate the extent of their learning well.Design/methodology/approach– Comic strips have been used in a number of ways to enhance knowledge and education, including for disaster risk reduction (DRR). Their use as learning stimuli is outlined, showing their historical context as well as their potential for future use. The methodology used included classroom observations, coupled with interviews with some of the class.Findings– The research showed that pre-school children engaged with and responded to the comic strips in a positive manner while the blank comic strips allowed learners to make sense of the topic through the retelling of the story, allowing them to be placed within a schema of understanding deemed essential for deeper level learning.Originality/value– The research is significant because it shows that, even at a young age, complex cognitive process were engaged in order for learners to take their new knowledge, place it within the context of their own experience and re-tell it to others. This pattern of reflection, reasoning and testing is important for triple-loop learning, which may hold the key to truly resilient individuals and communities.
Mentorship in a Japanese graduate school: learning through apprenticeship
Authors: Sakamoto Mitsuyo , Tamanyu Lumi 
Published: February 2014

Purpose
– The purpose of this study is to investigate a four-year mentorship program for Japanese graduate students at a private university in Tokyo, Japan. The following research questions were investigated: First, does mentorship provide effective and adequate preparation needed for graduate students to perform competitively (e.g. attending conferences, publishing in journals, etc.) in academic forums? Second, what kinds of benefits are gained by the mentees? Third, what factors are conducive to the benefits accrued by the mentees? Fourth, what are the obstacles to providing an effective mentorship program?

Design/methodology/approach
– Adopting narrative approach as its research method, this study collected and analyzed reflective essays from 13 Japanese students in a TESOL (Teaching English to Speakers of Other Languages) program.

Findings
– Particular types of mentoring which encouraged active participation in scholarly activities through appropriately scaffolded inductions into academia led to increased mentee confidence in terms of making the transition from student to scholar.

Research limitations/implications
– The students should not remain assistants on the periphery of academia, but rather play active roles to extend their knowledge and expertise to something that they can attain only with appropriate scaffolding (Vygotsky, 1981). In order to promote such mentorship, it is emphasized that institutional support is indispensable, and that the significance of solid mentorship programs should be re-acknowledged and discussed on an official level.

Originality/value
– The study of mentoring within a Japanese context, in particular from the perspectives of sociocultural theory (Vygotsky, 1981) and Bandura's (1994, 1995) self-efficacy theory, is an under-researched area.
Multi-plant improvement programmes: a literature review and research agenda
Authors: H. Netland Torbjørn , Aspelund Arild 
Published: February 2014

Purpose– To advance the productivity of all plants in the network, multinational corporations develop and deploy multi-plant improvement programmes. In this paper, the authors systematically review and synthesise the emerging literature on multi-plant improvement programmes. The paper aims to discuss these issues.Design/methodology/approach– Through a systematic manual search, the authors examine 15 top journals from operations management, general management and international business literature in the time span between 1998 and 2011.Findings– The authors found 30 papers that specifically deal with operational improvement programmes in a multi-plant international setting, of which only nine take a headquarter perspective. This low number contrasts sharply with the magnitude and importance of such programmes in industry. The authors discuss key dimensions that explain how multi-plant improvement programmes result in the adopting, adapting, acting or avoiding of programme practices in subsidiaries and propose a related research agenda.Research limitations/implications– The authors affirm that a new field is in the making, withIJOPMas the leading professional journal. Further empirical research is called for, but particular methodological caution must be paid to the phenomenon of acting in subsidiaries.Originality/value– No coherent stream of research has addressed multi-plant improvement programmes. This paper represents a focused review that supports the further development of the field.
Collaborative green innovation in emerging countries: a social capital perspective
Authors: Chen Ping-Chuan , Hung Shiu-Wan 
Published: February 2014

Purpose– The new paradigm for green innovation has already shifted to a collaborative model. This study aims to examine how environmental collaboration across organizational boundaries affects green innovation from the social capital perspective.Design/methodology/approach– This study used structural equation modeling method to analyze the innovation performance of 237 Taiwanese firms. Non-response bias was also assessed statistically and appropriate measures taken to minimise the impact of common method variance.Findings– The empirical results showed that: structural capital and cognitive capital have a positive influence on relational capital, relational capital plays a significant role in green management and in turn leads to greater innovation. To achieve effective green innovation, companies should leverage their social capital in order to produce additional competitive advantages through environmental collaboration.Originality/value– With the relative scarcity of resources and the increased pressures for environmental sustainability, there is an increasing interest in studying collaborative green innovation in emerging countries. Unlike many other empirical studies, this study makes an important contribution to the literature by examining how environmental collaboration in emerging countries affects green innovation from the social capital perspective in a detailed manner.
Outshopping in rural periodic markets: a retailing opportunity
Authors: Kumar Velayudhan Sanal 
Published: February 2014

Purpose– The study seeks to understand the influences on the prevalence of rural retailing institution of periodic markets. It examines the influence of access to and population of the location on the performance of periodic markets and their effect on the competition between periodic markets and local rural retail stores.Design/methodology/approach– Simultaneous cross-sectional study on census data is used to understand changes in performance of periodic markets in the context of growth in retail stores.Findings– The superior performance of local retail shop compared to outshopping in periodic markets is contrary to observation in literature developed in the context of urban outshopping.Practical implications– Retail chains need to develop a separate program for location of outlets that serve rural areas as access influences retail performance. In rural areas marketers can use traditional periodic markets in addition to conventional retail store given the limited inter-format retail competition.Originality/value– This is one of the few studies to explicitly examine periodic markets as a retail format. Outshopping is studied in the context of growth in local retail stores unlike earlier studies in the urban context where the local stores exhibit reduced sales.