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Article
Publication date: 6 May 2021

Tim Chen, N. Kapronand, C.Y. Hsieh and J. Cy Chen

To guarantee the asymptotic stability of discrete-time nonlinear systems, this paper aims to propose an evolved bat algorithm fuzzy neural network (NN) controller algorithm.

Abstract

Purpose

To guarantee the asymptotic stability of discrete-time nonlinear systems, this paper aims to propose an evolved bat algorithm fuzzy neural network (NN) controller algorithm.

Design/methodology/approach

In evolved fuzzy NN modeling, the NN model and linear differential inclusion representation are established for the arbitrary nonlinear dynamics. The control problems of the Fisher equation and a temperature cooling fin for high-speed aerospace vehicles will be described and demonstrated. The signal auxiliary controlled system is represented for the nonlinear parabolic partial differential equation (PDE) systems and the criterion of stability is derived via the Lyapunov function in terms of linear matrix inequalities.

Findings

This representation is constructed by sector nonlinearity, which converts the nonlinear model to a multiple rule base for the linear model and a new sufficient condition to guarantee the asymptotic stability.

Originality/value

This study also injects high frequency as an auxiliary and the control performance to stabilize the nonlinear high-speed aerospace vehicle system.

Details

Aircraft Engineering and Aerospace Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1748-8842

Keywords

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Article
Publication date: 10 December 2019

Tim Chen and J.C.Y. Chen

This paper aims to address the robust controller design problem for a class of fuzzy C-means clustering algorithm that is robust against both the plant parameter…

Abstract

Purpose

This paper aims to address the robust controller design problem for a class of fuzzy C-means clustering algorithm that is robust against both the plant parameter perturbations and controller gain variations. Based on Takagi–Sugeno (T-S) fuzzy model description, the stability and control problems of nonlinear systems are studied.

Design/methodology/approach

A recently proposed integral inequality is selected based on the free-weight matrix, and the less conservative stability criterion is given in the form of linear matrix inequalities (LMIs).

Findings

Under the premise that the controller and the system share the same, the method does not require the number of membership functions and rules.

Practical implications

Furthermore, the modified controller in a large-scale nonlinear system is utilized as a stability criterion for a closed-loop T-S fuzzy system obtained by LMI, and is rearranged by a machine learning membership function.

Originality/value

The closed-loop controller criterion is derived by energy functions to guarantee the stability of systems. Finally, an example is given to demonstrate the results.

Details

Aircraft Engineering and Aerospace Technology, vol. 92 no. 2
Type: Research Article
ISSN: 1748-8842

Keywords

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Article
Publication date: 5 June 2020

Tim Chen, Nai Jau Dkuo and C.Y.J. Chen

This paper aims to propose a composite form of the robust disturbance fuzzy control scheme. The proposed method uses the benefits of fuzzy system modeling and Lyapunov…

Abstract

Purpose

This paper aims to propose a composite form of the robust disturbance fuzzy control scheme. The proposed method uses the benefits of fuzzy system modeling and Lyapunov direct methods.

Design/methodology/approach

The effciency of the control technique was demonstrated with assistance of numerical simulation in control problems of unmanned aerial vehicle (UAV) simulation.

Findings

To evaluate the control performance, the comparison of the proposed controller was made with conventional control techniques. The Lyapunov stability theorem has been used to testify for asymptotic stability and convergence of the closed loop system.

Practical implications

Implementation of the control law in the real world environment can be easier due to significant reduction in the fuzzy rules, tuning parameters and computation stages.

Originality/value

Simulation results confirm that the proposed control scheme performs remarkably well in terms of the robustness and disturbance attenuation.

Details

Aircraft Engineering and Aerospace Technology, vol. 92 no. 7
Type: Research Article
ISSN: 1748-8842

Keywords

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Article
Publication date: 19 July 2019

Tim Chen, Safiullahand Khurram and CYJ Cheng

This paper aims to deal with the problem of the global stabilization for a class of tension leg platform (TLP) nonlinear control systems.

Abstract

Purpose

This paper aims to deal with the problem of the global stabilization for a class of tension leg platform (TLP) nonlinear control systems.

Design/methodology/approach

It is well-known that, in general, the global asymptotic stability of the TLP subsystems does not imply the global asymptotic stability of the composite closed-loop system.

Findings

An effective approach is proposed to control chaos via the combination of fuzzy controllers, fuzzy observers and dithers.

Research limitations/implications

If a fuzzy controller and a fuzzy observer cannot stabilize the chaotic system, a dither, as an auxiliary of the controller and the observer, is simultaneously introduced to asymptotically stabilize the chaotic system.

Originality/value

Thus, the behavior of the closed-loop dithered chaotic system can be rigorously predicted by establishing that of the closed-loop fuzzy relaxed system.

Details

Engineering Computations, vol. 36 no. 7
Type: Research Article
ISSN: 0264-4401

Keywords

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Article
Publication date: 31 December 2006

Juan Ignacio Vazquez, Diego López de Ipiña and Iñigo Sedano

Despite several efforts during the last years, the web model and semantic web technologies have not yet been successfully applied to empower Ubiquitous Computing…

Abstract

Despite several efforts during the last years, the web model and semantic web technologies have not yet been successfully applied to empower Ubiquitous Computing architectures in order to create knowledge‐rich environments populated by interconnected smart devices. In this paper we point out some problems of these previous initiatives and introduce SoaM (Smart Objects Awareness and Adaptation Model), an architecture for designing and seamlessly deploying web‐powered context‐aware semantic gadgets. Implementation and evaluation details of SoaM are also provided in order to identify future research challenges.

Details

International Journal of Web Information Systems, vol. 2 no. 3/4
Type: Research Article
ISSN: 1744-0084

Keywords

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Article
Publication date: 6 February 2017

Liangjun Zhou, Jerred Junqi Wang, Xiaoying Chen, Chundong Lei, James J. Zhang and Xiao Meng

Building upon the framework of glocalization, the purpose of this paper is to summarize the development of National Basketball Association (NBA) in Chinese market, explore…

Abstract

Purpose

Building upon the framework of glocalization, the purpose of this paper is to summarize the development of National Basketball Association (NBA) in Chinese market, explore its successful and unsuccessful places, and propose strategies of glocalization for the NBA as well as other overseas sport leagues.

Design/methodology/approach

The current case study was organized by summarizing the developmental history of NBA in China, analyzing its current promotional practices, investigating into its marketing strategies, and extrapolating practical references for other sport leagues aiming to penetrating into the Chinese marketplace.

Findings

The current case study concluded that when facing the current challenges, the NBA needs to bring authentic American cultural commodities while adding Chinese characteristics to accommodate local fans. Meanwhile, the NBA management needs to continue seeking ways to work out and through the differences in government models and cultural contexts between China and USA. In addition, this study suggested that the research framework of glocalization would be an ever intriguing inquiry needed for other sport organizations or leagues seeking expansion to overseas markets.

Originality/value

A thorough case study with the NBA that has achieved huge successes in Chinese markets will provide valuable implications for sport leagues to broaden their overseas markets.

Details

International Journal of Sports Marketing and Sponsorship, vol. 18 no. 1
Type: Research Article
ISSN: 1464-6668

Keywords

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Article
Publication date: 8 March 2021

Muna E. Raypah, Mutharasu Devarajan and Shahrom Mahmud

One major problem in the lighting industry is the thermal management of the devices. Handling of thermal resistance from solder point to the ambiance of the light-emitting…

Abstract

Purpose

One major problem in the lighting industry is the thermal management of the devices. Handling of thermal resistance from solder point to the ambiance of the light-emitting diode (LED) package is linked to the external thermal management that includes a selection of the cooling mode, design of heatsink/substrate and thermal interface material (TIM). Among the significant factors that increase the light output of the of the LED system are efficient substrate and TIM. In this work, the influence of TIM on the luminous flux performance of commercial indium gallium aluminium phosphide (InGaAlP) low-power (LP) LEDs was investigated.

Design/methodology/approach

One batch of LEDs was mounted directly onto substrates which were glass-reinforced epoxy (FR4) and aluminium-based metal-core printed circuit boards (MCPCBs) with a dielectric layer of different thermal conductivities. Another batch of LEDs was prepared in a similar way, but a layer of TIM was embedded between the LED package and substrate. The TIMs were thermally conductive epoxy (TCE) and thermally conductive adhesive (TCA). The LED parameters were measured by using the integrated system of thermal transient tester (T3Ster) and thermal-radiometric characterization of LEDs at various input currents.

Findings

With the employment of TIM, the authors found that the LED’s maximum luminous flux was significantly higher than the value mentioned in the LED datasheet, and that a significant reduction in thermal resistance and junction temperature was revealed. The results showed that for a system with low thermal resistance, the maximum luminous flux appeared to occur at a higher power level. It was found that the maximum luminous flux was 24.10, 28.40 and 36.00 lm for the LEDs mounted on the FR4 and two MCPCBs, respectively. After TCA application on the LEDs, the maximum luminous flux values were 32.70, 36.60 and 37.60 lm for the FR4 and MCPCBs, respectively. Moreover, the findings demonstrated that the performance of the LED mounted on the FR4 substrate was more affected by the employment of the TIM than that of MCPCBs.

Research limitations/implications

One of the major problems in the lighting industry is the thermal management of the device. In many low-power LED applications, the air gap between the two solder pads is not filled up. Heat flow is restricted by the air gap leading to thermal build-up and higher thermal resistance resulting in lower maximum luminous flux. Among the significant factors that increase the light output of the LED system are efficient substrate and TIM.

Practical implications

The findings in this work can be used as a method to improve thermal management of LP LEDs by applying thermal interface materials that can offer more efficient and brighter LP LEDs. Using aluminium-based substrates can also offer similar benefits.

Social implications

Users of LP LEDs can benefit from the findings in this work. Brighter automotive lighting (signalling and backlighting) can be achieved, and better automotive lighting can offer better safety for the people on the street, especially during raining and foggy weather. User can also use a lower LED power rating to achieve similar brightness level with LED with higher power rating.

Originality/value

Better thermal management of commercial LP LEDs was achieved with the employment of thermal interface materials resulting in lower thermal resistance, lower junction temperature and brighter LEDs.

Details

Soldering & Surface Mount Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0954-0911

Keywords

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Article
Publication date: 13 February 2017

Zaheer Khan and Tim Vorley

The purpose of this paper is to examine the role of big data text analytics as an enabler of knowledge management (KM). The paper argues that big data text analytics…

Abstract

Purpose

The purpose of this paper is to examine the role of big data text analytics as an enabler of knowledge management (KM). The paper argues that big data text analytics represents an important means to visualise and analyse data, especially unstructured data, which have the potential to improve KM within organisations.

Design/methodology/approach

The study uses text analytics to review 196 articles published in two of the leading KM journals – Journal of Knowledge Management and Journal of Knowledge Management Research & Practice – in 2013 and 2014. The text analytics approach is used to process, extract and analyse the 196 papers to identify trends in terms of keywords, topics and keyword/topic clusters to show the utility of big data text analytics.

Findings

The findings show how big data text analytics can have a key enabler role in KM. Drawing on the 196 articles analysed, the paper shows the power of big data-oriented text analytics tools in supporting KM through the visualisation of data. In this way, the authors highlight the nature and quality of the knowledge generated through this method for efficient KM in developing a competitive advantage.

Research limitations/implications

The research has important implications concerning the role of big data text analytics in KM, and specifically the nature and quality of knowledge produced using text analytics. The authors use text analytics to exemplify the value of big data in the context of KM and highlight how future studies could develop and extend these findings in different contexts.

Practical implications

Results contribute to understanding the role of big data text analytics as a means to enhance the effectiveness of KM. The paper provides important insights that can be applied to different business functions, from supply chain management to marketing management to support KM, through the use of big data text analytics.

Originality/value

The study demonstrates the practical application of the big data tools for data visualisation, and, with it, improving KM.

Details

Journal of Knowledge Management, vol. 21 no. 1
Type: Research Article
ISSN: 1367-3270

Keywords

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Article
Publication date: 1 May 1998

Brian H. Kleiner

Presents a special issue, enlisting the help of the author’s students and colleagues, focusing on age, sex, colour and disability discrimination in America. Breaks the…

Abstract

Presents a special issue, enlisting the help of the author’s students and colleagues, focusing on age, sex, colour and disability discrimination in America. Breaks the evidence down into manageable chunks, covering: age discrimination in the workplace; discrimination against African‐Americans; sex discrimination in the workplace; same sex sexual harassment; how to investigate and prove disability discrimination; sexual harassment in the military; when the main US job‐discrimination law applies to small companies; how to investigate and prove racial discrimination; developments concerning race discrimination in the workplace; developments concerning the Equal Pay Act; developments concerning discrimination against workers with HIV or AIDS; developments concerning discrimination based on refusal of family care leave; developments concerning discrimination against gay or lesbian employees; developments concerning discrimination based on colour; how to investigate and prove discrimination concerning based on colour; developments concerning the Equal Pay Act; using statistics in employment discrimination cases; race discrimination in the workplace; developments concerning gender discrimination in the workplace; discrimination in Japanese organizations in America; discrimination in the entertainment industry; discrimination in the utility industry; understanding and effectively managing national origin discrimination; how to investigate and prove hiring discrimination based on colour; and, finally, how to investigate sexual harassment in the workplace.

Details

Equal Opportunities International, vol. 17 no. 3/4/5
Type: Research Article
ISSN: 0261-0159

Keywords

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Article
Publication date: 1 April 2020

Liang-Chih Huang, Cheng-Chen Lin and Szu-Chi Lu

Based on the job demands-resources model, the present study proposes viewing abusive supervision as one type of job demand causing employees' emotional exhaustion, which…

Abstract

Purpose

Based on the job demands-resources model, the present study proposes viewing abusive supervision as one type of job demand causing employees' emotional exhaustion, which results in psychological withdrawal behavior. In addition, job crafting can be viewed as a means to acquire job resources, and it buffers the influence of abusive supervision on employees' emotional exhaustion. Moreover, the present study also proposes the moderating effect of job crafting on abusive supervision and psychological withdrawal behavior will be mediated by emotional exhaustion.

Design/methodology/approach

Considering the issue of common method variance, data were not only collected in a multi-temporal research design but also tested by Harman's one-factor test. In addition, a series of confirmatory factor analyses was conducted to ensure the discriminant validity of measures. The moderated mediation hypotheses were tested on a sample of 267 participants.

Findings

The process model analysis showed that emotional exhaustion partially mediates the relationship between abusive supervision and psychological withdrawal behavior. Moreover, job crafting buffers the detrimental effect of abusive supervision on emotional exhaustion, and the less exhausted employees exhibit less psychological withdrawal behavior than those exhausted.

Originality/value

This study proposed a moderated mediation model to examine how and when abusive supervision leads to more employees' psychological withdrawal behaviors, and found that emotional exhaustion is one potential mechanism and job crafting is one potential moderator. Specifically, it was revealed that employees view abusive supervision as a kind of social and organizational aspect of job demands which will exacerbate emotional exhaustion, and, in turn, lead to more psychological withdrawal behavior. However, when employees view themselves as job crafter, they can adopt various job crafting behaviors to decrease the emotional exhaustion, and thus less psychological withdrawal behavior.

Details

Personnel Review, vol. 49 no. 9
Type: Research Article
ISSN: 0048-3486

Keywords

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