Xiaotong Jiang, Xiaosheng Cheng, Qingjin Peng, Luming Liang, Ning Dai, Mingqiang Wei and Cheng Cheng
It is a challenge to print a model with the size that is larger than the working volume of a three-dimensional (3D) printer. The purpose of this paper is to present a feasible…
Abstract
Purpose
It is a challenge to print a model with the size that is larger than the working volume of a three-dimensional (3D) printer. The purpose of this paper is to present a feasible approach to divide a large model into small printing parts to fit the volume of a printer and then assemble these parts into the final model.
Design/methodology/approach
The proposed approach is based on the skeletonization and the minima rule. The skeleton of a printing model is first extracted using the mesh contraction and the principal component analysis. The 3D model is then partitioned preliminarily into many smaller parts using the space sweep method and the minima rule. The preliminary partition is finally optimized using the greedy algorithm.
Findings
The skeleton of a 3D model can effectively represent a simplified version of the geometry of the 3D model. Using a model’s skeleton to partition the model is an efficient way. As it is generally desirable to have segmentations at concave creases and seams, the cutting position should be located in the concave region. The proposed approach can partition large models effectively to well retain the integrity of meaningful parts.
Originality/value
The proposed approach is new in the rapid prototyping field using the model skeletonization and the minima rule. Based on the authors’ knowledge, there is no method that concerns the integrity of meaningful parts for partitioning. The proposed method can achieve satisfactory results by the integrity of meaningful parts and assemblability for most 3D models.
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Dongfei Li, Hongtao Wang and Ning Dai
This paper aims to propose a method for automatic design of additive manufacturing (AM) flow channel paths driven by path length and pressure loss. The research focuses on the…
Abstract
Purpose
This paper aims to propose a method for automatic design of additive manufacturing (AM) flow channel paths driven by path length and pressure loss. The research focuses on the automatic design of channel paths, intending to achieve the shortest flow channel length or minimum pressure loss and improve the design efficiency of AM parts.
Design/methodology/approach
The initial layout of the flow channels is redesigned to consider the channels print supports. Boundary conditions and constraints are defined according to the redesigned channels layout, and the equation consisting of channel length and pressure loss is used as the objective function. Then the path planning simulation is performed based on particle swarm algorithm. The proposed method describes the path of flow channels using spline cures. The spline curve is controlled by particle (one particle represents a path), and the particle is randomly generated within the design space. After the path planning simulation is completed, the generated paths are used to create 3D parts.
Findings
Case study 1 demonstrates the automatic design of hydraulic spool valve. Compared to conventional spool valve, the pressure loss was reduced by 86% and the mass was reduced by 83%. The design results of case study 2 indicate that this approach is able to find the shortest channel path with lower computational cost.
Originality/value
The automatic design method of flow channel paths driven by path length and pressure loss presented in this paper provides a novel solution for the creation of AM flow components.
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Amanda Wilkie and Sean Stein Smith
This chapter explores blockchain's five key elements ‒ distribution, encryption, immutability, tokenization, and decentralization. It also examines blockchain's potential to…
Abstract
This chapter explores blockchain's five key elements ‒ distribution, encryption, immutability, tokenization, and decentralization. It also examines blockchain's potential to revolutionize today's businesses by looking at the efficiency and transparency blockchain brings to business processes. In addition, the chapter discusses the added benefits of traceability and potentially decreasing long-term costs before reviewing some of the known technical challenges blockchain faces today especially pertaining to commercial and enterprise adoption. Limited block size and low-transaction rates potentially inhibit blockchain's ability to scale to meet the needs of current and future enterprises. The lack of blockchain standards, along with creating multiple blockchains, complicates interoperability between the various blockchain platforms. The chapter concludes by offering potential solutions to blockchain's current technical challenges and how enterprises might adapt blockchain in the future.
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Shuai Yang, Wenjie Zhao, Yongzhen Ke, Jiaying Liu and Yongjiang Xue
Due to the inability to directly apply an intra-oral image with esthetic restoration to restore tooth shape in the computer-aided design system, this paper aims to propose a…
Abstract
Purpose
Due to the inability to directly apply an intra-oral image with esthetic restoration to restore tooth shape in the computer-aided design system, this paper aims to propose a method that can use two-dimensional contours obtained from the image for the three-dimensional dental mesh model restoration.
Design/methodology/approach
First, intra-oral image and smiling image are taken from the patient, then teeth shapes of the images are designed based on esthetic restoration concepts and the pixel coordinates of the teeth’s contours are converted into the vertex coordinates in the three-dimensional space. Second, the dental mesh model is divided into three parts – active part, passive part and fixed part – based on the teeth’s contours of the mesh model. Third, the vertices from the teeth’s contours of the dental model are matched with ones from the intra-oral image and with the help of matching operation, the target coordinates of each vertex in the active part can be calculated. Finally, the Laplacian-based deformation algorithm and mesh smoothing algorithm are performed.
Findings
Benefitting from the proposed method, the dental mesh model with esthetic restoration can be quickly obtained based on the intra-oral image that is the result of doctor-patient communication. Experimental results show that the quality of restoration meets clinical needs, and the typical time cost of the method is approximately one second. So the method is both time-saving and user-friendly.
Originality/value
The method provides the possibility to design personalized dental esthetic restoration solutions rapidly.
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Abstract
Purpose
In recent years, railway systems worldwide have faced challenges such as the modernization of engineering projects, efficient management of intelligent digital railway equipment, rapid growth in passenger and freight transport demands, customized transport services and ubiquitous transport safety. The transformation toward intelligent digital transformation in railways has emerged as an effective response to the formidable challenges confronting the railway industry, thereby becoming an inevitable global trend in railway development.
Design/methodology/approach
This paper, therefore, conducts a comprehensive analysis of the current state of global railway intelligent digital transformation, focusing on the characteristics and applications of intelligent digital transformation technology. It summarizes and analyzes relevant technologies and applicable scenarios in the realm of railway intelligent digital transformation, theoretically elucidating the development process of global railway intelligent digital transformation and, in practice, providing guidance and empirical examples for railway intelligence and digital transformation.
Findings
Digital and intelligent technologies follow a wave-like pattern of continuous iterative evolution, progressing from the early stages, to a period of increasing attention and popularity, then to a phase of declining interest, followed by a resurgence and ultimately reaching a mature stage.
Originality/value
The results offer reference and guidance to fully leverage the opportunities presented by the latest wave of the digitalization revolution, accelerate the overall upgrade of the railway industry and promote global collaborative development in railway intelligent digital transformation.
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Maxwell Fordjour Antwi-Afari, Heng Li, David John Edwards, Erika Anneli Pärn, De-Graft Owusu-Manu, Joonoh Seo and Arnold Yu Lok Wong
Work-related low back disorders (LBDs) are prevalent among rebar workers although their causes remain uncertain. The purpose of this study is to examine the self-reported…
Abstract
Purpose
Work-related low back disorders (LBDs) are prevalent among rebar workers although their causes remain uncertain. The purpose of this study is to examine the self-reported discomfort and spinal biomechanics (muscle activity and spinal kinematics) experienced by rebar workers.
Design/methodology/approach
In all, 20 healthy male participants performed simulated repetitive rebar lifting tasks with three different lifting weights, using either a stoop (n = 10) or a squat (n = 10) lifting posture, until subjective fatigue was reached. During these tasks, trunk muscle activity and spinal kinematics were recorded using surface electromyography and motion sensors, respectively.
Findings
A mixed-model, repeated measures analysis of variance revealed that an increase in lifting weight significantly increased lower back muscle activity at L3 level but decreased fatigue and time to fatigue (endurance time) (p < 0.05). Lifting postures had no significant effect on spinal biomechanics (p < 0.05). Test results revealed that lifting different weights causes disproportional loading upon muscles, which shortens the time to reach working endurance and increases the risk of developing LBDs among rebar workers.
Research limitations/implications
Future research is required to: broaden the research scope to include other trades; investigate the effects of using assistive lifting devices to reduce manual handling risks posed; and develop automated human condition-based solutions to monitor trunk muscle activity and spinal kinematics.
Originality/value
This study fulfils an identified need to study laboratory-based simulated task conducted to investigate the risk of developing LBDs among rebar workers primarily caused by repetitive rebar lifting.
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Huakang Liang and Xiaoxiao Shi
The demanding nature of construction industry poses serious health risks to construction workers. In recent years, construction health management (CHM) has gained much attention…
Abstract
Purpose
The demanding nature of construction industry poses serious health risks to construction workers. In recent years, construction health management (CHM) has gained much attention to ensure a healthier and safer workplace. However, there is still lack of a systematic review to bring together the disaggregated studies and determine the development status of this research field. As essential for addressing health issues in construction industry, a bibliometric and content-based review on of previous CHM studies would be presented in this paper.
Design/methodology/approach
In total, 753 journal articles published in Web of Science core collection from 1990 to 2020 were examined using a systematic review. Bibliometric analysis concentrated on the analysis of publication and citation pattern of CHM research while content analysis was employed to identify main health hazards, levels of analysis and topical focuses.
Findings
The results indicated that the USA was the leading country in this research domain. Five health hazards together with 17 research topics at different levels of analysis were classified to allow researchers to track the structure and temporal evolution of the research field. Finally, three emerging trends and a set of research agenda were proposed to guide future research directions.
Originality/value
It is the first to highlight the issues of occupational health management from the perspective of construction workers. It contributes to the field of construction health management by clarifying the knowledge structure, emerging trends and future research directions. It offers valuable guidance and in-depth understanding to researchers, practitioners and policymakers to further promote construction workers' health performance.
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Benna Hu, Laifu Wen and Xuemei Zhou
Vertical electrical sounding (VES) and Rayleigh wave exploration are widely used in the exploration of near-surface structure, but both have limitations. This study aims to make…
Abstract
Purpose
Vertical electrical sounding (VES) and Rayleigh wave exploration are widely used in the exploration of near-surface structure, but both have limitations. This study aims to make full use of the advantages of the two methods, reduce the multiple solutions of single inversion and improve the accuracy of the inversion. Thus, a nonlinear joint inversion method of VES and Rayleigh wave exploration based on improved differential evolution (DE) algorithm was proposed.
Design/methodology/approach
Based on the DE algorithm, a new initialization strategy was proposed. Then, taking AK-type with high-velocity interlayer model and HA-type with low-velocity interlayer model near the surface as examples, the inversion results of different methods were compared and analyzed. Then, the proposed method was applied to the field data in Chengde, Hebei Province, China. The stratum structure was accurately depicted and verified by drilling.
Findings
The synthetic data and field data results showed that the joint inversion of VES and Rayleigh wave data based on the improved DE algorithm can effectively improve the interpretation accuracy of the single-method inversion and had strong stability and large generalizable ability in near-surface engineering problems.
Originality/value
A joint inversion method of VES and Rayleigh wave data based on improved DE algorithm is proposed, which can improve the accuracy of single-method inversion.
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Countryside planning has become popular due to the improvement in the economic level of China. A rural construction planning permission system is an important means to guide and…
Abstract
Countryside planning has become popular due to the improvement in the economic level of China. A rural construction planning permission system is an important means to guide and standardize village construction. Therefore, this study investigates the current condition of rural planning in Guangdong and the general condition of Guangdong Province. Village planning problems, such as the village theory, lack of characteristics, and lack of coordination, are also presented. The bottleneck of the construction village planning permission system is presented. A “three-step” strategy and mode transformation (i.e., legal, personalized, and independent steps) is established based on the analysis of the Guangdong rural planning problems. Finally, the general requirements for village construction under the permission system are proposed along with the study of the village planning in Guangdong, which is the representative case. Therefore, this study provides a reference for the effective linkage between village planning and the rural construction planning permission system.
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Xinghua Shan, Zhiqiang Zhang, Fei Ning, Shida Li and Linlin Dai
With the yearly increase of mileage and passenger volume in China's high-speed railway, the problems of traditional paper railway tickets have become increasingly prominent…
Abstract
Purpose
With the yearly increase of mileage and passenger volume in China's high-speed railway, the problems of traditional paper railway tickets have become increasingly prominent, including complexity of business handling process, low efficiency of ticket inspection and high cost of usage and management. This paper aims to make extensive references to successful experiences of electronic ticket applications both domestically and internationally. The research on key technologies and system implementation of railway electronic ticket with Chinese characteristics has been carried out.
Design/methodology/approach
Research in key technologies is conducted including synchronization technique in distributed heterogeneous database system, the grid-oriented passenger service record (PSR) data storage model, efficient access to massive PSR data under high concurrency condition, the linkage between face recognition service platforms and various terminals in large scenarios, and two-factor authentication of the e-ticket identification code based on the key and the user identity information. Focusing on the key technologies and architecture the of existing ticketing system, multiple service resources are expanded and developed such as electronic ticket clusters, PSR clusters, face recognition clusters and electronic ticket identification code clusters.
Findings
The proportion of paper ticket printed has dropped to 20%, saving more than 2 billion tickets annually since the launch of the application of E-ticketing nationwide. The average time for passengers to pass through the automatic ticket gates has decreased from 3 seconds to 1.3 seconds, significantly improving the efficiency of passenger transport organization. Meanwhile, problems of paper ticket counterfeiting, reselling and loss have been generally eliminated.
Originality/value
E-ticketing has laid a technical foundation for the further development of railway passenger transport services in the direction of digitalization and intelligence.