Search results

1 – 10 of 15
Per page
102050
Citations:
Loading...
Access Restricted. View access options
Article
Publication date: 17 May 2011

Ping Liu, Xiaolong Gu, Xinbing Zhao and Xiaogang Liu

The purpose of this paper is to evaluate the influence of microvia design on solder joint reliability and to present a printed circuit board (PCB) microvia design approach capable…

495

Abstract

Purpose

The purpose of this paper is to evaluate the influence of microvia design on solder joint reliability and to present a printed circuit board (PCB) microvia design approach capable of reducing or eliminating voiding in solder joints.

Design/methodology/approach

Five different types of via‐in‐pad designs were incorporated into a test vehicle and their performance evaluated using a variety of standard reliability tests.

Findings

Solid vias, composed of 99.5 percent pure copper can be used to eliminate voiding in solder joints. Such vias are also much more robust than those employing metallic paste or other filled materials. Solid vias with flat surfaces have been shown to be able to meet the requirements of common reliability test standards and to offer a process compatible with traditional PCB manufacturing.

Research limitations/implications

The occurrence of voiding in solder joints has been shown to be significantly influenced by microvia design. Although a design is reported for reducing/eliminating voiding, other factors that can cause voiding should be investigated. Also, further extended accelerated reliability testing could be undertaken to determine comparative long‐term reliability.

Originality/value

Serious voiding in solder joints is a major threat to the quality and reliability of electronics assemblies, mainly due to its role as a stress concentrator and particularly with the move to lead‐free assembly. Methods for reducing and eliminating the occurrence of voiding are needed by electronics assemblers and this work proposes one such method that can be implemented at the circuit board design stage.

Details

Circuit World, vol. 37 no. 2
Type: Research Article
ISSN: 0305-6120

Keywords

Access Restricted. View access options
Article
Publication date: 7 July 2023

Xiaojie Xu and Yun Zhang

The Chinese housing market has witnessed rapid growth during the past decade and the significance of housing price forecasting has undoubtedly elevated, becoming an important…

194

Abstract

Purpose

The Chinese housing market has witnessed rapid growth during the past decade and the significance of housing price forecasting has undoubtedly elevated, becoming an important issue to investors and policymakers. This study aims to examine neural networks (NNs) for office property price index forecasting from 10 major Chinese cities for July 2005–April 2021.

Design/methodology/approach

The authors aim at building simple and accurate NNs to contribute to pure technical forecasts of the Chinese office property market. To facilitate the analysis, the authors explore different model settings over algorithms, delays, hidden neurons and data-spitting ratios.

Findings

The authors reach a simple NN with three delays and three hidden neurons, which leads to stable performance of about 1.45% average relative root mean square error across the 10 cities for the training, validation and testing phases.

Originality/value

The results could be used on a standalone basis or combined with fundamental forecasts to form perspectives of office property price trends and conduct policy analysis.

Details

Journal of Financial Management of Property and Construction , vol. 29 no. 1
Type: Research Article
ISSN: 1366-4387

Keywords

Access Restricted. View access options
Article
Publication date: 10 October 2024

Xiaolong Yuan, Yongyong Yang, Feng Wang, Qian Ding, Mianlin Deng, Wendian Shi and Xudong Zhao

Drawing upon social information processing theory, this study investigates the correlation between self-serving leadership and employee expediency. It also explores the mediating…

139

Abstract

Purpose

Drawing upon social information processing theory, this study investigates the correlation between self-serving leadership and employee expediency. It also explores the mediating effect of self-interest motivation and the moderating effect of trait mindfulness.

Design/methodology/approach

A total of 147 part-time MBA students were enlisted to participate in a scenario experiment (Study 1), and 291 valid employee questionnaires were collected through a multiple-time point survey (Study 2). SPSS 23.0, MPLUS 8.0 and PROCESS programs were used to analyze the data and test the hypotheses.

Findings

Study 1 illustrated a positive correlation between self-serving leadership and employee expediency. It also identified self-interest motivation as a mediating factor in the correlation between self-serving leadership and expediency. Study 2 replicated the results obtained in Study 1 and expanded upon them by demonstrating that trait mindfulness moderates the association between self-serving leadership and self-interest motivation. Additionally, trait mindfulness moderates the indirect effect of self-serving leadership on expediency.

Practical implications

This research argues that organizations should take steps to prevent self-serving leadership in order to reduce employee expediency. Furthermore, it is advisable to provide ethics training to employees who exhibit high trait mindfulness, as they show increased sensitivity to self-serving leadership and are more likely to engage in unethical behavior.

Originality/value

This study expands the existing research on the ethical outcomes of self-serving leadership and contributes to a deeper understanding of the negative aspects of trait mindfulness.

Details

Personnel Review, vol. 54 no. 1
Type: Research Article
ISSN: 0048-3486

Keywords

Access Restricted. View access options
Article
Publication date: 6 December 2023

Xiaolong Lu, Xudong Sui, Xiao Zhang, Zhen Yan and Junying Hao

This study aims to investigate the effect of V doping on the microstructure, chemical stability, mechanical and vacuum tribological behavior of sputtered MoS2 coatings.

130

Abstract

Purpose

This study aims to investigate the effect of V doping on the microstructure, chemical stability, mechanical and vacuum tribological behavior of sputtered MoS2 coatings.

Design/methodology/approach

The MoS2-V coatings are fabricated via tuning V target current by magnetron sputtering technique. The structural characteristic and elemental content of the coatings are measured by field emission scanning electron microscopy, X-ray diffractometer, electron probe X-ray micro-analyzer, Raman, X-ray photoelectron spectroscopy, high resolution transmission electron microscope and energy dispersive spectrometer. The hardness of the deposited coatings are tested by a nanoindentation technique. The vacuum tribological properties of MoS2-V coatings are studied by a ball-on-disc tribometer.

Findings

Introducing V into the MoS2 coatings results in a more compact microstructure. The hardness of the coatings increases with the doping of V. The MoS2-V coating deposited at a current of 0.2 A obtains the lowest friction coefficient (0.043) under vacuum. As the amount of V doping increases, the wear rate of the coating decreases first and then increases, among which the coating deposited at a current of 0.5 A has the lowest wear rate of 2.2 × 10–6 mm3/N·m.

Originality/value

This work elucidates the role of V doping on the lubrication mechanism of MoS2 coatings in a vacuum environment, and the MoS2-V coating is expected to be applied as a solid lubricant in space environment.

Details

Industrial Lubrication and Tribology, vol. 76 no. 1
Type: Research Article
ISSN: 0036-8792

Keywords

Access Restricted. View access options
Article
Publication date: 1 December 2005

Yih‐Rern Peng, Xiaolong Qi and Christos Chrisafides

There are many considerations that have to be taken into account when balancing the properties epoxy‐based laminate and prepreg materials must have in order to meet the array of…

989

Abstract

Purpose

There are many considerations that have to be taken into account when balancing the properties epoxy‐based laminate and prepreg materials must have in order to meet the array of electrical, thermal and mechanical demands of today's multilayer printed circuit boards. Aims to discuss two different curing systems that are commonly employed in current laminate and prepreg materials.

Design/methodology/approach

An examination of the two different curing systems – phenol novolac (PN) and dicyandiamide (DICY) based – that are commonly employed in current laminate and prepreg materials.

Findings

DICY curing systems have properties such as good flexibility, good adhesion and good processability but have poor thermal resistance, higher water absorption and poor anti‐CAF capability. Because PN resin systems utilize an aromatic ring structure, traditional PN cured epoxy resin results in having excellent thermal resistance, low water absorption and anti‐CAF capability.

Originality/value

Provides a comparison of interest to all those involved with laminate and prepreg materials in the circuit board industry.

Details

Circuit World, vol. 31 no. 4
Type: Research Article
ISSN: 0305-6120

Keywords

Available. Content available
Book part
Publication date: 2 July 2018

Yujie Chen, Zhifei Mao and Jack Linchuan Qiu

Abstract

Details

Super-Sticky Wechat and Chinese Society
Type: Book
ISBN: 978-1-78743-091-4

Access Restricted. View access options
Article
Publication date: 28 December 2023

Ankang Ji, Xiaolong Xue, Limao Zhang, Xiaowei Luo and Qingpeng Man

Crack detection of pavement is a critical task in the periodic survey. Efficient, effective and consistent tracking of the road conditions by identifying and locating crack…

247

Abstract

Purpose

Crack detection of pavement is a critical task in the periodic survey. Efficient, effective and consistent tracking of the road conditions by identifying and locating crack contributes to establishing an appropriate road maintenance and repair strategy from the promptly informed managers but still remaining a significant challenge. This research seeks to propose practical solutions for targeting the automatic crack detection from images with efficient productivity and cost-effectiveness, thereby improving the pavement performance.

Design/methodology/approach

This research applies a novel deep learning method named TransUnet for crack detection, which is structured based on Transformer, combined with convolutional neural networks as encoder by leveraging a global self-attention mechanism to better extract features for enhancing automatic identification. Afterward, the detected cracks are used to quantify morphological features from five indicators, such as length, mean width, maximum width, area and ratio. Those analyses can provide valuable information for engineers to assess the pavement condition with efficient productivity.

Findings

In the training process, the TransUnet is fed by a crack dataset generated by the data augmentation with a resolution of 224 × 224 pixels. Subsequently, a test set containing 80 new images is used for crack detection task based on the best selected TransUnet with a learning rate of 0.01 and a batch size of 1, achieving an accuracy of 0.8927, a precision of 0.8813, a recall of 0.8904, an F1-measure and dice of 0.8813, and a Mean Intersection over Union of 0.8082, respectively. Comparisons with several state-of-the-art methods indicate that the developed approach in this research outperforms with greater efficiency and higher reliability.

Originality/value

The developed approach combines TransUnet with an integrated quantification algorithm for crack detection and quantification, performing excellently in terms of comparisons and evaluation metrics, which can provide solutions with potentially serving as the basis for an automated, cost-effective pavement condition assessment scheme.

Details

Engineering, Construction and Architectural Management, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0969-9988

Keywords

Access Restricted. View access options
Article
Publication date: 15 July 2024

Xiaolong Lyu, Dan Huang, Liwei Wu and Ding Chen

Parameter estimation in complex engineering structures typically necessitates repeated calculations using simulation models, leading to significant computational costs. This paper…

60

Abstract

Purpose

Parameter estimation in complex engineering structures typically necessitates repeated calculations using simulation models, leading to significant computational costs. This paper aims to introduce an adaptive multi-output Gaussian process (MOGP) surrogate model for parameter estimation in time-consuming models.

Design/methodology/approach

The MOGP surrogate model is established to replace the computationally expensive finite element method (FEM) analysis during the estimation process. We propose a novel adaptive sampling method for MOGP inspired by the traditional expected improvement (EI) method, aiming to reduce the number of required sample points for building the surrogate model. Two mathematical examples and an application in the back analysis of a concrete arch dam are tested to demonstrate the effectiveness of the proposed method.

Findings

The numerical results show that the proposed method requires a relatively small number of sample points to achieve accurate estimates. The proposed adaptive sampling method combined with the MOGP surrogate model shows an obvious advantage in parameter estimation problems involving expensive-to-evaluate models, particularly those with high-dimensional output.

Originality/value

A novel adaptive sampling method for establishing the MOGP surrogate model is proposed to accelerate the procedure of solving large-scale parameter estimation problems. This modified adaptive sampling method, based on the traditional EI method, is better suited for multi-output problems, making it highly valuable for numerous practical engineering applications.

Details

Engineering Computations, vol. 41 no. 6
Type: Research Article
ISSN: 0264-4401

Keywords

Access Restricted. View access options
Article
Publication date: 7 June 2021

Sixian Chan, Jian Tao, Xiaolong Zhou, Binghui Wu, Hongqiang Wang and Shengyong Chen

Visual tracking technology enables industrial robots interacting with human beings intelligently. However, due to the complexity of the tracking problem, the accuracy of visual…

156

Abstract

Purpose

Visual tracking technology enables industrial robots interacting with human beings intelligently. However, due to the complexity of the tracking problem, the accuracy of visual target tracking still has great space for improvement. This paper aims to propose an accurate visual target tracking method based on standard hedging and feature fusion.

Design/methodology/approach

For this study, the authors first learn the discriminative information between targets and similar objects in the histogram of oriented gradients by feature optimization method, and then use standard hedging algorithms to dynamically balance the weights between different feature optimization components. Moreover, they penalize the filter coefficients by incorporating spatial regularization coefficient and extend the Kernelized Correlation Filter for robust tracking. Finally, a model update mechanism to improve the effectiveness of the tracking is proposed.

Findings

Extensive experimental results demonstrate the superior performance of the proposed method comparing to the state-of-the-art tracking methods.

Originality/value

Improvements to existing visual target tracking algorithms are achieved through feature fusion and standard hedging algorithms to further improve the tracking accuracy of robots on targets in reality.

Details

Industrial Robot: the international journal of robotics research and application, vol. 48 no. 5
Type: Research Article
ISSN: 0143-991X

Keywords

Access Restricted. View access options
Article
Publication date: 14 June 2022

Xiaolong Xue, Xiliang Sun, Weirui Xue, Yaxin Wang and Longhui Liao

Conscious of the benefits building information modeling (BIM) has brought about to the architecture, engineering, construction and operations (AECO) industry, the Chinese…

510

Abstract

Purpose

Conscious of the benefits building information modeling (BIM) has brought about to the architecture, engineering, construction and operations (AECO) industry, the Chinese government has been driving BIM adoption. Nonetheless, its acceptance and proliferation in China remain stagnant. Most relevant literature focuses on BIM diffusion at the industry and organizational levels, but the impact of non-managerial practitioners executing BIM or the traditional drafting approach in day-to-day work tends to be disregarded. This study aims to extend theoretical models pertaining to technology acceptance to understand non-managerial practitioners’ perceptions toward working with BIM in China.

Design/methodology/approach

A new BIM acceptance model was proposed based on previous technology acceptance theories. After a pilot study, a survey was conducted with 153 non-managerial practitioners in the Chinese AECO industry.

Findings

Among factors impacting non-managerial practitioners’ BIM acceptance in China, performance expectancy and task-technology fit significantly and positively influence behavioral intention to accept BIM, while the impacts from effort expectancy, social influence and facilitating conditions are not essential.

Research limitations/implications

Management strategies, such as improving non-managerial staff’s benefits and sense of BIM usefulness, selecting suitable tools to match with the staff’s tasks and promoting a middle-out approach in parallel with top-down interventions, are proposed for Chinese AECO organizations to enhance BIM acceptance.

Originality/value

Few studies have explored BIM acceptance from the perspective of non-managerial users in the Chinese AECO industry, especially using the theories related to technology acceptance. The BIM acceptance model developed in this study is different from those used in previous global studies in terms of influencing factors.

Details

Engineering, Construction and Architectural Management, vol. 30 no. 9
Type: Research Article
ISSN: 0969-9988

Keywords

1 – 10 of 15
Per page
102050