Xichen Chen, Alice Yan Chang-Richards, Antony Pelosi, Yaodong Jia, Xuesong Shen, Mohsin K. Siddiqui and Nan Yang
With interest in modern construction methods and new technologies on the rise, construction companies globally are increasingly looking at how to embrace new ideas and engage with…
Abstract
Purpose
With interest in modern construction methods and new technologies on the rise, construction companies globally are increasingly looking at how to embrace new ideas and engage with new approaches to do things better. A significant amount of work has been carried out investigating the use of individual technologies in the construction sector. However, there is no holistic understanding of the new and emerging technologies that have had proven benefits for construction projects. To fill this gap, this paper aims to provide a landscape of technologies that have been implemented in the construction industry and the benefits associated with their implementation.
Design/methodology/approach
A systematic review approach and PRISMA guidelines were used. A total of 175 articles published between 2001 and 2020 were identified and thoroughly reviewed.
Findings
The results show that a total of 26 technologies were identified from the literature, and these can be categorised into five groups in terms of their functionality in construction process, namely: (1) data acquisition, (2) analytics, (3) visualisation, (4) communication and (5) design and construction automation. Digital technologies, especially for data acquisition and visualisation, generally appear to underpin and enable innovation in many aspects of construction. Improvements in work efficiency, health and safety, productivity, quality and sustainability have been cited as being the primary benefits of using these technologies. Of these, building information modelling (BIM) appears to be the single most commonly used technology thus far. With the development of computer technology, BIM has constantly been used in combination with other technologies/tools such as unmanned aerial vehicles/systems (unmanned aerial vehicle (UAV)/UAS), geographic information systems (GIS), light detection and ranging (LiDAR) and multidimensional modelling to realise a specifically defined benefit.
Practical implications
The findings from this review would help construction practitioners identify the types of technologies that can be implemented in different stages of construction projects to achieve desired outcomes, and thus, make appropriate decisions on technology investment and adoption. This review also suggests that to reap the full potential that these technologies offer, aside from construction companies changing their culture and business models, corresponding changes in the construction sector’s operating systems related to building regulation, education and training, as well as contracting and procurement are required.
Originality/value
This paper undertakes a comprehensive systematic review of studies on technology implementation in the construction sector published between 2001 and 2020. It is the first attempt internationally to provide a holistic picture of technologies that have been studied and implemented in construction projects.
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Shuang Wang, Gedong Jiang, Xuesong Mei, Chuang Zou, Xian Zhang and Hao Zhang
Because of the compact structure, short flexspline (FS) harmonic drive (HD) is increasingly used. The stress calculation of FS is very important in design and optimization of HD…
Abstract
Purpose
Because of the compact structure, short flexspline (FS) harmonic drive (HD) is increasingly used. The stress calculation of FS is very important in design and optimization of HD system. This paper aims to study the stress calculation methods for short FS, based on mechanics analysis and finite element method (FEM).
Design/methodology/approach
A rapid stress calculation method, based on mechanics analysis, is proposed for the short FS of HD. To verify the stress calculation precision of short FS, a complete finite element model of HD is established. The results of stress and deformation of short FS in different lengths are solved by FEM.
Findings
Through the rapid calculation method, the analytical relationship between circumferential stress and length of cylinder was obtained. And the circumferential stress has proportional relation with the reciprocal of squared length. The FEM results verified that the rapid stress calculation method could obtain accurate results.
Research limitations/implications
The rapid mechanics analysis method is practiced to evaluate the strength of FS at the design stage of HD. And the complete model of HD could contribute to improving the accuracy of FEM results.
Originality/value
The rapid calculation method is developed based on mechanics analysis method of cylinder and equivalent additional bending moment model, through which the analytical relationship between circumferential stress and length of cylinder was obtained. The complete three-dimensional finite element model of HD takes the stiffness of bearing into consideration, which can be used in the numerical simulation in the future work to improve the accuracy.
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Xuesong Cao, Xican Li, Wenjing Ren, Yanan Wu and Jieya Liu
This study aims to improve the accuracy of hyperspectral estimation of soil organic matter content.
Abstract
Purpose
This study aims to improve the accuracy of hyperspectral estimation of soil organic matter content.
Design/methodology/approach
Based on the uncertainty in spectral estimation, 76 soil samples collected in Zhangqiu District, Jinan City, Shandong Province, were studied in this paper. First, the spectral transformation of the spectral data after denoising was carried out by means of 11 transformation methods such as reciprocal and square, and the estimation factor was selected according to the principle of maximum correlation. Secondly, the grey weighted distance was used to calculate the grey relational degree between the samples to be estimated and the known patterns, and the local linear regression estimation model of soil organic matter content was established by using the pattern samples closest to the samples to be identified. Thirdly, the models were optimized by gradually increasing the number of modeling samples and adjusting the decision coefficient, and a comprehensive index was constructed to determine the optimal predicted value. Finally, the determination coefficient and average relative error are used to evaluate the validity of the model.
Findings
The results show that the maximum correlation coefficient of the seven estimated factors selected is 0.82; the estimation results of 14 test samples are of high accuracy, among which the determination coefficient R2 = 0.924, and the average relative error is 6.608%.
Practical implications
Studies have shown that it is feasible and effective to estimate the content of soil organic matter by using grey correlation local linear regression model.
Originality/value
The paper succeeds in realizing both the soil organic matter hyperspectral grey relation estimating pattern based on the grey relational theory and the estimating pattern by using the local linear regression.
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Qing Peng, Xuesong Tang and Yuxin Zheng
Extensively public concern on “Huge Executive Compensation” makes it urgent to investigate the reasonability of high executive compensation. The purpose of this paper is to…
Abstract
Purpose
Extensively public concern on “Huge Executive Compensation” makes it urgent to investigate the reasonability of high executive compensation. The purpose of this paper is to explore the effectiveness of compensation contracting based on the specific responsibility of executives. More specifically, this paper is to examine whether high compensation is helpful to mitigate agency problems.
Design/methodology/approach
Considering that board secretaries of listed companies are responsible for information disclosure in China, this paper examines the effect of board secretaries’ excess compensation on firms’ disclosure quality using listed company data from 2007 to 2015. The first measure of disclosure quality is based on the disclosure violation behavior of firms, and the second is KV value that represents the extent to which the investors relay on the stock trading volume. To provide additional confidence that the findings are robust, this paper further conducts two indirect tests based on rumors and cost of equity capital.
Findings
The results show that board secretaries’ excess compensation is negatively associated with the probability of information disclosure violation and also negatively associated with firms’ KV value, suggesting firms that pay high compensation to their information providers are more likely to provide high-quality disclosures. Besides, this paper further finds that board secretaries’ excess compensation is negatively related to the incidence of rumors, the number of rumors incurred or the cost of equity capital.
Research limitations/implications
Overall, the findings provide support to the efficient contracting of executive compensation, which implies that highly paid board secretaries would be better information providers than those poorly paid.
Practical implications
This paper provides empirical evidence that firms’ disclosure quality can be improved by modifying the compensation contract of information providers. This may indicate a new way to improve the quality of disclosures, so as to mitigate the agency problem.
Social implications
In spite of the public criticism on executive excess compensation, the high compensation is not always a signal of manipulation, collusion and self-interest. It also can be a signal of individual talents and great efforts. Board secretaries are worth to be highly paid if they can improve firms’ disclosures, thereby reducing the incidence of rumors and reducing the cost of equity capital.
Originality/value
This paper is the first research to examine the effectiveness of compensation contracting based on information providers’ disclosure responsibility in the Chinese context. It documents a positive relation between board secretaries’ excess compensation and corporate disclosure quality.
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Xian Zhang, Gedong Jiang, Hao Zhang, Xialun Yun and Xuesong Mei
The purpose of this paper is to analyze the time-dependent reliability of harmonic drive.
Abstract
Purpose
The purpose of this paper is to analyze the time-dependent reliability of harmonic drive.
Design/methodology/approach
The transient finite element analysis (FEA) of harmonic drive is established to calculate the stress under different loads. Combined with the residual strength model and random variables, the time-dependent reliability model of harmonic drive is deduced by the stochastic perturbation method and Edgeworth series. Based on accelerated life tests, the degradation parameters are estimated by maximizing likelihood function. Under variable load, the key stress from transient FEA is transformed into probability density function by kernel density estimation, and the residual strength model is modified by adding adjustment factors to deal with strength degradation under different loads.
Findings
The critical position of stress concentration from transient FEA is consistent with the fatigue fracture position at the accelerated life test sample. Compared with the time-dependent reliability method with equivalent circular-shell static stress or empirical degradation parameters, the proposed method has the smallest prediction error of failure life. Under variable load, the state function should be expanded to second-order series for avoiding error items relevant to variance. The failure life expectation under random variable load is smaller than that under constant load.
Originality/value
The time-dependent reliability method of harmonic drive is firstly proposed under constant and variable load. The transient FEA of harmonic drive is established to calculate the stress for strength analysis. The accelerated life test of harmonic drive is conducted for degradation parameters estimation. The adjustment factor is added to the residual strength model for strength degradation under different loads.
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Wen Liu, Shuangchao Huang, Hongfeng Qi, Xin Zhao, Shulin Liang and Xuesong Jin
Dynamic low adhesion (DLA) has become an urgent problem for the high-speed wheel-rail system because of continuous decrease of adhesion redundancy in the past decades. This…
Abstract
Purpose
Dynamic low adhesion (DLA) has become an urgent problem for the high-speed wheel-rail system because of continuous decrease of adhesion redundancy in the past decades. This article aims to provide a simulation method to reveal the mechanism of DLA under high-frequency vibrations.
Design/methodology/approach
A transient wheel-rail rolling contact model is developed for a typical Chinese high-speed railway system using the explicit finite element (FE) method. Instantaneous adhesion exploitation levels are studied in the time domain, for which driving cases over corrugated rails are taken as an example. A speed up to 500 km/h is considered together with different traction coefficients and corrugation dimensions. DLA is expected when the instantaneous adhesion exploitation level reaches 1.0, that is adhesion saturates and full sliding contact occurs.
Findings
The instantaneous adhesion exploitation level can be very high in the presence of corrugation, even at low traction coefficients. DLA is found to occur as great vertical unloading takes place and causes a significant increase of creepage. An approach is further developed to determine the critical depth of corrugation over which DLA occurs.
Originality/value
This study employs the transient wheel-rail rolling contact model to predict the instantaneous adhesion exploitation level under high-frequency vibrations. The presented results reveal a mechanism of DLA being beneficial to guidelines for future railway practice.
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Xian Zhang, Gedong Jiang, Hao Zhang, Xialun Yun and Xuesong Mei
The purpose of this paper is to analyze the dependent competing failure reliability of harmonic drive (HD) with strength failure and degradation failure.
Abstract
Purpose
The purpose of this paper is to analyze the dependent competing failure reliability of harmonic drive (HD) with strength failure and degradation failure.
Design/methodology/approach
Based on life tests and stiffness degradation experiments, Wiener process is used to establish the accelerated performance degradation model of HD. Model parameter distribution is estimated by Bayesian inference and Markov Chain Monte Carlo (MCMC) and stiffness degradation failure samples are obtained by a three-step sampling method. Combined with strength failure samples of HD, copula function is used to describe the dependence between strength failure and stiffness degradation failure.
Findings
Strength failure occurred earlier than degradation failure under high level accelerated condition; degradation failure occurred earlier than strength failure under medium- or low-level accelerated condition. Gumbel copula is the optimum copula function for dependence modeling of strength failure and stiffness degradation failure. Dependent competing failure reliability of HD is larger than independent competing failure reliability.
Originality/value
The reliability evaluation method of dependent competing failure of HD with strength failure and degradation failure is first proposed. Performance degradation experiments during accelerated life test (ALT), step-down ALT and life test under rated condition are conducted for Wiener process based step-down accelerated performance degradation modeling.
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Gökçe Mehmet AY and Osman Nuri ÇELİK
Plasma transferred arc (PTA) coating is a novel method for surface-coating applications. In this method, the substrate is melted using a plasma arc, and surfacing agents such as…
Abstract
Purpose
Plasma transferred arc (PTA) coating is a novel method for surface-coating applications. In this method, the substrate is melted using a plasma arc, and surfacing agents such as carbides are introduced to the melt pool. The purpose of this study is to investigate the effect of boron carbide (B4C) in nickel-based coating on AISI 4140 steel.
Design/methodology/approach
Samples were tested on a ball-on-disc wear device, and the microstructure, as well as wear properties, were investigated using SEM and XRD.
Findings
The effect of B4C addition was shown to be linear, with a p-value of 0.0248, indicating strong evidence. The reason for this increase was found to be the increase in third-body generation resulting from hard phases that form couples with the soft base material, nickel. It was concluded that using 6 per cent B4C was the optimal solution.
Originality/value
In the literature, the effect of neither low temperature on a nickel coating with B4C nor B4C as a single surfacing agent in a nickel base has been investigated.