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Article
Publication date: 31 March 2020

Yajing Gu, Hongyan Yan and Yuanguo Zhu

The purpose of this paper is to propose an iterative Legendre technique to deal with a continuous optimal control problem (OCP).

134

Abstract

Purpose

The purpose of this paper is to propose an iterative Legendre technique to deal with a continuous optimal control problem (OCP).

Design/methodology/approach

For the system in the considered problem, the control variable is a function of the state variables and their derivatives. State variables in the problem are approximated by Legendre expansions as functions of time t. A constant matrix is given to express the derivatives of state variables. Therefore, control variables can be described as functions of time t. After that, the OCP is converted to an unconstrained optimization problem whose decision variables are the unknown coefficients in the Legendre expansions.

Findings

The convergence of the proposed algorithm is proved. Experimental results, which contain the controlled Duffing oscillator problem demonstrate that the proposed technique is faster than existing methods.

Originality/value

Experimental results, which contained the controlled Duffing oscillator problem demonstrate that the proposed technique can be faster while securing exactness.

Details

Engineering Computations, vol. 37 no. 8
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 8 June 2022

Jun Kang, Jingyi Lan, Hongyan Yan, Wen Li and Xuemei Shi

This study aims to investigate the antecedents of mobile Internet users’ perception of information sensitivity (PIS) and willingness to provide personal information (WTP). It…

373

Abstract

Purpose

This study aims to investigate the antecedents of mobile Internet users’ perception of information sensitivity (PIS) and willingness to provide personal information (WTP). It provides insights about how these antecedents influence users’ perceived information sensitivity and willingness to provide.

Design/methodology/approach

An online survey of mobile Internet users was conducted in China, generating a total of 1,000 qualified responses for analysis.

Findings

Results reveal the differential effects of some major antecedents of mobile Internet users’ perceived information sensitivity and willingness to provide (individual disposition to value privacy, age, gender, app type and privacy concerns) and such impact vary across low-, medium- and high-privacy segments.

Originality/value

This study provides insights into the antecedents of mobile Internet users’ attitudes towards personal information privacy. It also extends the understanding of users’ perceived information sensitivity and willingness to provide such information comparatively among four countries.

Details

Marketing Intelligence & Planning, vol. 40 no. 6
Type: Research Article
ISSN: 0263-4503

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Article
Publication date: 29 January 2020

Song-Rui Liu, Xiao-Qun Dai and Yan Hong

The water evaporation rate (WER) is not only crucial for fabric drying, but also an important parameter affecting cooling from a body wearing sweat wetted clothing. The purpose of…

217

Abstract

Purpose

The water evaporation rate (WER) is not only crucial for fabric drying, but also an important parameter affecting cooling from a body wearing sweat wetted clothing. The purpose of this paper is to predict the WERs of wet textile materials in a pre-defined environment.

Design/methodology/approach

The maximum water evaporation rate (WERmax) from a saturated surface in a pre-defined environment was first predicted based on the Lewis relationship between the evaporative and the convective heat transfer in this paper. The prediction results were validated by the comparisons with experimental measurements in various environments obtained in this paper and reported in the literature.

Findings

Experiment results show that the ratios of WERs to WERmax are lower than 100 percent but higher than 50 percent, which confirmed that the prediction of WERmax is reliable. The temperature decrease of the wet material surface due to evaporation was considered to account for the difference between measured WERs and the WERmax, and the WER variation among materials. The lower ratios of WERs to WERmax in the higher wind condition were speculated to be due to the greater temperature decrease caused by the increased evaporation.

Practical implications

It provides a reliable way to obtain both WERmax and WER (WERmax multiplied by a proper ratio), which can be useful in clothing physiological modeling to predict clothing comfort.

Originality/value

This study contributes to the understanding of the evaporation process of textile materials.

Details

International Journal of Clothing Science and Technology, vol. 32 no. 3
Type: Research Article
ISSN: 0955-6222

Keywords

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Article
Publication date: 7 August 2017

Hongyan Shi, Xiaoke Lin and Yun Wang

The purposes of this paper are to study the characterization of drill bit breakage in printed circuit board (PCB) drilling process based on high-speed video analysis and to…

302

Abstract

Purpose

The purposes of this paper are to study the characterization of drill bit breakage in printed circuit board (PCB) drilling process based on high-speed video analysis and to provide an important reference for micro drill bit breakage prediction.

Design/methodology/approach

Based on PCB drilling experiment, the high-speed camera was used to observe the micro drill breakage process and the chip removal process. The variation of chip in the drilling process was studied and one of the key reasons for the drill bit breakage was analysed. Finally, the swing angles’ feature during the breakage process of the micro drill was analysed and researched with the image processing tools of MATLAB.

Findings

The micro drill was prone to breakage mainly because of the blocked chips. The breakage process of the micro drill can be divided into the stage of stable chips evacuation, the stage of blocked chips and the stage of drill bit breakage. The radians of swing angles were basically in the range of ±0.01 when the drilling possess is normal. But when the radians of swing angles considerably exceeded the range of ±0.01, the micro drill bit may be fractured.

Originality/value

This paper presented the method to study the characterization of drill bit breakage in the PCB drilling process by using high-speed video analysis technology. Meanwhile, an effective suggestion about monitoring the radians of swing angles to predict the breakage of micro drill bit was also provided.

Details

Circuit World, vol. 43 no. 3
Type: Research Article
ISSN: 0305-6120

Keywords

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Article
Publication date: 10 May 2018

Hongyan Shi, Xiaoke Lin, Qiuxin Yan and Xiong Liang

The purpose of this paper was to study the influence of properties of printed circuit boards (PCBs) on the temperature during micro drilling and obtain the influential mechanism…

107

Abstract

Purpose

The purpose of this paper was to study the influence of properties of printed circuit boards (PCBs) on the temperature during micro drilling and obtain the influential mechanism of PCBs based on temperature measurement.

Design/methodology/approach

Experiments were carried out to study the influence mechanism of PCB properties on micro hole drilling temperature under high spindle speed. The temperature measurement platform was applied, then the influence of components ratio of PCBs on the temperature of micro-drilling was analyzed by using comparative analysis method. The mass ratio of each kind of material in the PCB was defined as four levels and the influence mechanism of properties of PCBs based on temperature measurement was summarized.

Findings

Average filler and lower resin would have a positive impact on micro hole drilling temperature, and the smaller filler size and the even distribution would make it better.

Originality/value

An infrared temperature measurement platform was applied and influential mechanism of PCB properties on temperature was analyzed, which could provide the reference value on the optimization of temperature during micro drilling.

Details

Circuit World, vol. 44 no. 3
Type: Research Article
ISSN: 0305-6120

Keywords

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Article
Publication date: 1 August 2016

Hongyan Shi, Qiuxin Yan and Shengzhi Chen

The purpose of this paper is to study the movement characteristics of micro drill bit during entry period in printed circuit board (PCB) high-speed drilling and to present an…

167

Abstract

Purpose

The purpose of this paper is to study the movement characteristics of micro drill bit during entry period in printed circuit board (PCB) high-speed drilling and to present an effective method to conduct quantitative analysis of the wandering of drill bit based on high-speed video capturing.

Design/methodology/approach

Based on the high-speed camera technology, experiments are conducted to get a series of time sequence images and the wandering of micro drill tip and the radial run-out of drill body, and the max-deformation of drill bit are calculated by using a quantitative analysis method. Finally, the movement characteristics of micro drill bit during entry drilling period PCB high-speed drilling are evaluated.

Findings

With the increasing spindle speed, the radial run-out of drill body decreases gradually, whereas the wandering amplitude of the drill point gradually increases; micro drill bit itself has an ability of positioning deviation correction after contacting the entry sheet; the feed rate within a certain range could slightly worsen the deformation of drill tip at the instant of impingement.

Research limitations/implications

With the improvement of spindle speed, the camera’s shooting speed needed will increase accordingly, thus, the resolution of the pictures will decline, which always affects the analysis precision.

Originality/value

A series of effective methods to conduct quantitative analysis of the wandering micro drill bit by using high-speed camera technology is presented; a reference for the optimization of micro-hole drilling is provided.

Details

Circuit World, vol. 42 no. 3
Type: Research Article
ISSN: 0305-6120

Keywords

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Article
Publication date: 19 September 2018

Hongyan Shi, Xiaoke Lin, Qiuxin Yan and JiaNan Zhang

The purpose of this paper is to study and obtain the influence of resin and filler properties of printed circuit board (PCB) on the drilling force during micro drilling.

100

Abstract

Purpose

The purpose of this paper is to study and obtain the influence of resin and filler properties of printed circuit board (PCB) on the drilling force during micro drilling.

Design/methodology/approach

Experiments were carried out to study the influence of PCB on micro-hole drilling force under high spindle speed. A drilling force measurement system was applied, and then, the influence of resin and filler properties of PCBs on the force was analyzed. The proportion of resin and filler in the PCB was defined as four levels, and the influence of PCBs based on the drilling force measurement was summarized.

Findings

The drilling force decreased with the decrease in the feed rate, and lower filler (16-30 per cent) and average resin (31-50 per cent) would have a positive impact on the drilling force. At the same time, the size of uniform and fine fillers would help to reduce the drilling force.

Originality/value

The drilling force measurement system was applied, and the influence of PCBs on force was analyzed, which could provide a reference value on the optimization of the drilling force during micro drilling.

Details

Circuit World, vol. 44 no. 4
Type: Research Article
ISSN: 0305-6120

Keywords

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Article
Publication date: 3 May 2016

Hongyan Shi, Jiali Ning and Qiuxin Yan

The purpose of this paper is to calibrate the surface emissivity of micro drill bit and to investigate the effect of different drilling parameters on the temperature of micro…

782

Abstract

Purpose

The purpose of this paper is to calibrate the surface emissivity of micro drill bit and to investigate the effect of different drilling parameters on the temperature of micro drill bit in printed circuit board (PCB) micro drilling process.

Design/methodology/approach

The surface emissivity of micro drill bit was obtained by experiments. Analysis of variance (ANOVA) was applied in this study to analysis the effect of different drilling parameters on the temperature of micro drill bit in PCB micro hole drilling. The most significant influencing factor on micro drill bit temperature was achieved by ANOVA.

Findings

First, the surface emissivity of cemented carbide rod decreased from 0.4 to 0.32 slowly with temperature in the range of 50-220°C. Second, the most significant influencing factor on the micro drill bit temperature was spindle speed among the drilling parameters including spindle speed, retract rate and infeed rate.

Research limitations/implications

In this paper, the influence of roughness of black coating, carbide rod and micro drill bit on the surface emissivity calibration and the temperature measurement was not considered.

Originality/value

A new simple method has been presented to calibrate the surface emissivity of micro drill bit. Through calibrating the surface emissivity of micro drill bit, the temperature of micro drill bit can be measured accurately by infrared thermometry. Analyzing the influences of different drilling parameters on the temperature of micro drill bit, the mechanism of drilling parameters on drilling temperature is achieved. The basis for the selection of drilling parameters to improve the hole quality is enhanced.

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Article
Publication date: 24 July 2023

Yan Tao, Hongyan Ke and Ziye Zhang

The paper examines whether the hybrid strategy can generate high performance and what hybrid strategy configurations are more conducive to high performance.

360

Abstract

Purpose

The paper examines whether the hybrid strategy can generate high performance and what hybrid strategy configurations are more conducive to high performance.

Design/methodology/approach

This paper explores the complex causal relationships between six strategic elements (marketing, growth, R&D, capital, efficiency, stability) and firm performance. From a configurational approach, the authors utilize necessary condition analysis, time-series qualitative comparative analysis, and typical case extraction techniques to analyze 944 balanced panel data from 118 Chinese ICT firms during 2013–2020.

Findings

Chinese ICT sector firms do not rely on pure strategies (prospector or defender) to achieve high performance. The hybrid strategy is conducive to high performance. Only specific hybrid strategy configurations, including stable growth, innovative efficiency, and two-way player types, could enable firms to perform well. Six strategic elements do not constitute a necessary condition for high performance.

Originality/value

This paper proposed an integrated qualitative comparative analysis scheme, proved the effectiveness of the hybrid strategy on firm performance, and revealed how hybrid strategy configurations generate high performance.

Details

Journal of Organizational Change Management, vol. 36 no. 4
Type: Research Article
ISSN: 0953-4814

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Article
Publication date: 20 September 2022

Hongyan Dai, Yan Wen, Weihua Zhou, Tingting Tong and Xun Xu

The overuse and scarcity of resources emphasize the importance of the circular economy. The technology facilitated by Industry 4.0 stimulates the implementation of the circular…

516

Abstract

Purpose

The overuse and scarcity of resources emphasize the importance of the circular economy. The technology facilitated by Industry 4.0 stimulates the implementation of the circular economy that aims to reduce resource use and enhance operational efficiency. This study focuses on enhancing delivery efficiency in an online-to-offline (O2O) context from an Industry 4.0 technology-facilitated personal configuration perspective, that is, comparing in-house and crowdsourced delivery efficiency in China's O2O on-demand food delivery context.

Design/methodology/approach

The authors collect 128,152 orders from 38 restaurants of an online restaurant chain in China. The authors adopt multiple regression analysis to examine the delivery efficiency gap between in-house and crowdsourced deliverymen and the determinants of this efficiency gap.

Findings

The findings of this study reveal that crowdsourced deliverymen exhibit higher delivery efficiency, in terms of a shorter delivery time, than in-house deliverymen. In addition, the authors find that platforms providing monetary incentives or implementing late delivery penalties enlarge this efficiency gap. Furthermore, the authors show that external factors, such as working on weekends and bad weather conditions, contribute to the narrowing of this performance efficiency.

Practical implications

The study's findings suggest that platforms should use advanced technologies facilitated by Industry 4.0 to optimize their personnel configuration to enhance their delivery efficiency and reduce carbon emissions. The effective approaches include using financial incentives and improving working schedules.

Originality/value

The authors' findings contribute to the online fulfillment literature by focusing on delivery efficiency in the O2O context from the Industry 4.0 technology-facilitated personnel configuration perspective. The authors examine how internal and external factors moderate the performance efficiency between these two types of deliverymen.

Details

Industrial Management & Data Systems, vol. 123 no. 4
Type: Research Article
ISSN: 0263-5577

Keywords

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