Weidong Lei, Dandan Ke, Pengyu Yan, Jinsuo Zhang and Jinhang Li
This paper aims to correct the existing mixed integer programming (MIP) model proposed by Yadav et al. (2019) [“Bi-objective optimization for sustainable supply chain network…
Abstract
Purpose
This paper aims to correct the existing mixed integer programming (MIP) model proposed by Yadav et al. (2019) [“Bi-objective optimization for sustainable supply chain network design in omnichannel.”, Journal of Manufacturing Technology Management, Vol. 30 No. 6, pp. 972–986].
Design/methodology/approach
This paper first presents a counterexample to show that the existing MIP model is incorrect and then proposes an improved mixed integer linear programming (MILP) model for the considered problem. Last, a numerical experiment is conducted to test our improved MILP model.
Findings
This paper demonstrates that the formulations of the facility capacity constraints and the product flow balance constraints in the existing MIP model are incorrect and incomplete. Due to this reason, infeasible solutions could be identified as feasible ones by the existing MIP model. Hence, the optimal solution obtained with the existing MIP model could be infeasible. A counter-example is used to verify our observations. Computational results verify the effectiveness of our improved MILP model.
Originality/value
This paper gives a complete and correct formulation of the facility capacity constraints and the product flow balance constraints, and conducts other improvements on the existing MIP model. The improved MILP model can be easily implemented and would help companies to have more effective distribution networks under the omnichannel environment.
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Michele Chiumenti, Xin Lin, Miguel Cervera, Wei Lei, Yuxiang Zheng and Weidong Huang
This paper aims to address the numerical simulation of additive manufacturing (AM) processes. The numerical results are compared with the experimental campaign carried out at…
Abstract
Purpose
This paper aims to address the numerical simulation of additive manufacturing (AM) processes. The numerical results are compared with the experimental campaign carried out at State Key Laboratory of Solidification Processing laboratories, where a laser solid forming machine, also referred to as laser engineered net shaping, is used to fabricate metal parts directly from computer-aided design models. Ti-6Al-4V metal powder is injected into the molten pool created by a focused, high-energy laser beam and a layer of added material is sinterized according to the laser scanning pattern specified by the user.
Design/methodology/approach
The numerical model adopts an apropos finite element (FE) activation technology, which reproduces the same scanning pattern set for the numerical control system of the AM machine. This consists of a complex sequence of polylines, used to define the contour of the component, and hatches patterns to fill the inner section. The full sequence is given through the common layer interface format, a standard format for different manufacturing processes such as rapid prototyping, shape metal deposition or machining processes, among others. The result is a layer-by-layer metal deposition which can be used to build-up complex structures for components such as turbine blades, aircraft stiffeners, cooling systems or medical implants, among others.
Findings
Ad hoc FE framework for the numerical simulation of the AM process by metal deposition is introduced. Description of the calibration procedure adopted is presented.
Originality/value
The objectives of this paper are twofold: firstly, this work is intended to calibrate the software for the numerical simulation of the AM process, to achieve high accuracy. Secondly, the sensitivity of the numerical model to the process parameters and modeling data is analyzed.
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Ning Zhang, Ruru Pan, Lei Wang, Shanshan Wang, Jun Xiang and Weidong Gao
The purpose of this paper is to propose a novel method using support vector machine (SVM) classifiers for objective seam pucker evaluation. Features are extracted using wavelet…
Abstract
Purpose
The purpose of this paper is to propose a novel method using support vector machine (SVM) classifiers for objective seam pucker evaluation. Features are extracted using wavelet analysis and gray-level co-occurrence matrix (GLCM), and the samples are evaluated using SVM classifiers. The study aims to solve the problem of inappropriate parameters and large required samples in objective seam pucker evaluation.
Design/methodology/approach
Initially, seam pucker image was captured, and Edge detection and Hough transform were utilized to normalize the seam position and orientation. After cropping the image, the intensity was adjusted to the same identical level through histogram specification. Then, the standard deviations of the horizontal image and diagonal image, reconstructed using wavelet decomposition and reconstruction, were calculated based on parameter optimization. Meanwhile, GLCM was extracted from the restructured horizontal detail image, then the contrast and correlation of GLCM were calculated. Finally, these four features were imported to SVM classifiers based on genetic algorithm for evaluation.
Findings
The four extracted features reflected linear relationships among five grades. The experimental results showed that the classification accuracy was 96 percent, which catches up to the performance of human vision, and resolves ambiguity and subjective of the manual evaluation.
Originality/value
There are large required samples in current research. This paper provides a novel method using finite samples, and the parameters of the methods were discussed for parameter optimization. The evaluation results can provide references for analyzing the reason of wrinkles during garment manufacturing.
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Suggests that misunderstandings frequently occur when trying to understand Chinese language and culture, and so gives the implied meaning of various Chinese expressions and…
Abstract
Suggests that misunderstandings frequently occur when trying to understand Chinese language and culture, and so gives the implied meaning of various Chinese expressions and sayings such as greetings, thanks, respect, age, congratulations and taboo subjects.
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Huifang Liu, Weidong Chen, Pengwei Yuan and Xiaoqing Dong
This study aims to examine the impact of climate change on the total factor productivity (TFP) of tourism in Chinese cities. Using temperature and precipitation as proxies for…
Abstract
Purpose
This study aims to examine the impact of climate change on the total factor productivity (TFP) of tourism in Chinese cities. Using temperature and precipitation as proxies for climate change, the research analyzes both the direct negative effects of climate change on tourism productivity and the positive spillover effects on neighboring cities. In addition, it investigates how geographic location and economic development contribute to the variation in these effects. The study also explores the mechanisms through which government intervention and industrial structure upgrading influence these impacts.
Design/methodology/approach
This study uses a spatial Durbin model to analyze the relationship between climate change and tourism TFP in 287 Chinese cities from 2000 to 2020. Panel data is used, with temperature and precipitation serving as proxies for climate change. The model evaluates both the direct and spillover effects of climate change on tourism productivity, while also analyzing the mechanisms through which government intervention and industrial upgrading affect these relationships. The study further considers how geographic location and economic development impact the results.
Findings
This study finds that climate change directly reduces tourism TFP, while generating positive spillover effects for neighboring cities. Cities in the eastern and more economically developed regions are more sensitive to climate change, experiencing stronger impacts compared to cities in central and western regions. The findings suggest that government intervention and industrial structure upgrading are important mechanisms through which climate change affects tourism productivity in Chinese cities.
Originality/value
This research fills a gap in the literature regarding how climate change affects tourism productivity in developing countries, particularly in China. By applying a spatial Durbin model and panel data analysis, the study provides empirical evidence on both the direct and spillover effects of climate change on tourism productivity. It highlights the critical role of government intervention and industrial upgrading as mechanisms shaping the impact of climate change, offering new insights for policymakers and tourism businesses to address the challenges posed by climate change and enhance productivity and competitiveness.
目的
本研究旨在探讨气候变化对中国城市旅游全要素生产率的影响。通过温度和降水量作为气候变化的代理变量, 研究分析了气候变化对旅游全要素生产率的直接抑制效应及其对邻近城市的积极溢出效应。此外, 研究考察了地理位置与经济发展水平如何导致这些效应的异质性。通过分析政府干预和产业结构升级的机制, 本研究为气候变化影响旅游全要素生产率的机制分析提供了理论支持, 为提升发展中国家旅游竞争力提供了指导。
设计/方法论/研究方法
本研究采用空间杜宾模型分析2000年至2020年期间, 中国287个城市的气候变化与旅游全要素生产率之间的关系。研究使用面板数据, 温度和降水量作为气候变化的代理变量。模型分析了气候变化对旅游全要素生产率的直接效应与溢出效应, 并研究了政府干预与产业结构升级的机制效应。研究还考察了基于地理位置与经济发展水平的异质性影响, 提供了气候变化对城市旅游全要素生产率影响的综合分析。
研究发现
气候变化直接抑制旅游全要素生产率, 同时对邻近城市产生积极的溢出效应。东部城市及高经济水平地区对气候变化更为敏感, 影响强于中西部地区。研究发现, 政府干预与产业结构升级是气候变化影响中国城市旅游全要素生产率的关键机制。
原创性/价值
本研究填补了气候变化如何影响发展中国家, 尤其是中国, 旅游全要素生产率领域的研究空白。通过运用空间杜宾模型和面板数据分析, 提供了气候变化对旅游全要素生产率的直接效应与溢出效应的实证证据。研究强调了政府干预和产业结构升级作为气候变化影响旅游全要素生产率的主要机制。通过关注区域异质性与经济发展水平, 本研究为旅游企业与政策制定者应对气候变化挑战,提升生产力和竞争力提供了新的思路。
Objetivo
Este estudio examina el impacto del cambio climático en la productividad total de los factores (PTF) del turismo en las ciudades chinas. Utilizando la temperatura y las precipitaciones como indicadores del cambio climático, la investigación analiza tanto los efectos negativos directos del cambio climático sobre la productividad del turismo como los efectos indirectos positivos sobre las ciudades vecinas. Además, investiga cómo la ubicación geográfica y el desarrollo económico contribuyen a la variación de estos efectos. El estudio también explora los mecanismos a través de los cuales la intervención gubernamental y la mejora de la estructura industrial influyen en estos impactos.
Diseño/Metodología/Enfoque
Este estudio utiliza un modelo espacial de Durbin (SDM) para analizar la relación entre el cambio climático y la productividad total de los factores del turismo en 287 ciudades chinas entre 2000 y 2020. Se emplean datos de panel, en los que la temperatura y las precipitaciones sirven como variables sustitutivas del cambio climático. El modelo evalúa tanto los efectos directos como los indirectos del cambio climático sobre la productividad del turismo, al tiempo que analiza los mecanismos a través de los cuales la intervención gubernamental y la modernización industrial afectan a estas relaciones. El estudio examina además cómo influyen en los resultados la ubicación geográfica y el desarrollo económico.
Resultados
El estudio concluye que el cambio climático reduce directamente la productividad total de los factores del turismo, al tiempo que genera efectos indirectos positivos para las ciudades vecinas. Las ciudades de las regiones orientales y económicamente más desarrolladas son más sensibles al cambio climático y experimentan impactos más fuertes que las ciudades de las regiones centrales y occidentales. Los resultados sugieren que la intervención gubernamental y la mejora de la estructura industrial son mecanismos importantes a través de los cuales el cambio climático afecta a la productividad del turismo en las ciudades chinas.
Originalidad/Valor
Esta investigación llena un vacío en la literatura sobre cómo el cambio climático afecta a la productividad del turismo en los países en desarrollo, especialmente en China. Aplicando un modelo espacial de Durbin y un análisis de datos de panel, el estudio aporta pruebas empíricas sobre los efectos directos y indirectos del cambio climático en la productividad del turismo. Destaca el papel decisivo de la intervención pública y la modernización industrial como mecanismos que determinan el impacto del cambio climático, ofreciendo nuevas perspectivas a los responsables políticos y las empresas turísticas para afrontar los retos que plantea el cambio climático y mejorar la productividad y la competitividad.
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Abstract
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Mingda Ping, Xiangrui Ji, Yan Liu and Weidong Wang
To supply temporary pressure testing devices with favorable performance for emergency environments, this paper aims to present a pressure sensor with a central boss and…
Abstract
Purpose
To supply temporary pressure testing devices with favorable performance for emergency environments, this paper aims to present a pressure sensor with a central boss and straight-annular grooves. The structural feature is modeled and optimized by neural network-based method, and the device prototype is fabricated by 3D printing techniques.
Design/methodology/approach
The study initially compares mechanical properties of the proposed structure with two conventional designs using finite element analysis. The impacts from structural dimensions on sensor performance are modeled using a Backpropagation neural network and optimized through genetic algorithms. The sensing diaphragm is fabricated using stereolithography (SLA) 3D printing, while the piezoresistors and necessary interconnects are realized with screen printing techniques.
Findings
The experimental results demonstrate that the fabricated sensor exhibits a sensitivity of 2.8866 mV/kPa and a nonlinearity of 6.81% within the pressure range of 0–100 kPa. This performance is an improvement of 118% in sensitivity and a decrease of 54% in nonlinearity compared to flat diaphragm structure, highlighting the effectiveness of proposed diaphragm configuration.
Originality/value
This research offers a holistic methodology that encompasses the structural design, optimization and fabrication of pressure sensors. The proposed diaphragm and corresponding modelling method can provide a practical approach to enhance the measurement capabilities of pressure sensors. By leveraging SLA printing for diaphragm and screen printing for circuit, the prototype can be produced in a timely manner.
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Zeyu Li, Weidong Liu, Le Li, Zhi Liu and Feihu Zhang
Underwater shuttle is widely used in scenarios of deep sea transportation and observation. As messages are transmitted via the limited network, high transmission time-delay often…
Abstract
Purpose
Underwater shuttle is widely used in scenarios of deep sea transportation and observation. As messages are transmitted via the limited network, high transmission time-delay often leads to information congestion, worse control performance and even system crash. Moreover, due to the nonlinear issues with respect to shuttle’s heading motion, the delayed transmission also brings extra challenges. Hence, this paper aims to propose a co-designed method, for the purpose of network scheduling and motion controlling.
Design/methodology/approach
First, the message transmission scheduling is modeled as an optimization problem via adaptive genetic algorithm. The initial transmission time and the genetic operators are jointly encoded and adjusted to balance the payload in network. Then, the heading dynamic model is compensated for the delayed transmission, in which the parameters are unknown. Therefore, the adaptive sliding mode controller is designed to online estimate the parameters, for enhancing control precision and anti-interference ability. Finally, the method is evaluated by simulation.
Findings
The messages in network are well scheduled and the time delay is thus reduced, which increases the quality of service in network. The unknown parameters are estimated online, and the quality of control is enhanced. The control performance of the shuttle control system is thus increased.
Originality/value
The paper is the first to apply co-design method of message scheduling and attitude controlling for the underwater unmanned vehicle, which enhaces the control performance of the network control system.
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Zonglin Lei, Zunge Li and Yangyi Xiao
This study aims to investigate the surface modification on 20CrMnTi gear steel individually treated by diamond-like carbon films and nitride coatings.
Abstract
Purpose
This study aims to investigate the surface modification on 20CrMnTi gear steel individually treated by diamond-like carbon films and nitride coatings.
Design/methodology/approach
For this purpose, the mechanical properties of a-C:H, ta-C and AlCrSiN coatings are characterized by nano-indentation and scratch tests. The friction and wear behaviors of these three coatings are evaluated by ball-on-disc tribological experiments under dry contact conditions.
Findings
The results show that the a-C:H coating has the highest coating-substrate adhesion strength (495 mN) and the smoothest surface (Ra is about 0.045 µm) compared with the other two coatings. The AlCrSiN coating shows the highest mean coefficient of friction (COF), whereas the ta-C coating exhibits the lowest one (steady at about 0.16). The carbon-based coatings possess excellent self-lubricating properties compared with nitride ceramic ones, which effectively reduce the COF by about 64%. The major failure mode of carbon-based coatings in dry contact is slight abrasive wear. The damage of AlCrSiN coating is mainly adhesive wear and abrasive wear.
Originality/value
It is suggested that the carbon-based film can effectively improve the friction-reducing and wear resistance performance of the gear steel surface, which has a promising application prospect in the mechanical transmission field.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2023-0129/