Haonan Fan, Qin Dong and Naixuan Guo
This paper aims to propose a classification method for steel strip surface defects based on a mixed attention mechanism to achieve fast and accurate classification performance…
Abstract
Purpose
This paper aims to propose a classification method for steel strip surface defects based on a mixed attention mechanism to achieve fast and accurate classification performance. The traditional method of classifying surface defects of hot-rolled steel strips has the problems of low recognition accuracy and low efficiency in the industrial complex production environment.
Design/methodology/approach
The authors selected min–max scaling comparison method to filter the training results of multiple network models on the steel strip surface defect data set. Then, the best comprehensive performance model EfficientNet-B0 was refined. Based on this, the authors proposed two mixed attention addition methods, which include squeeze-excitation spatial mixed module and multilayer mixed attention mechanism (MMAM) module, respectively.
Findings
With these two methods, the authors achieved 96.72% and 97.70% recognition accuracy on the steel strip data set after data augmentation for adapting to the complex production environment, respectively. Using the transfer learning method, the EfficientNet-B0 based on MMAM obtained 100% recognition accuracy.
Originality/value
This study not only focuses on improving the recognition accuracy of the network model itself but also considers other performance indicators of the network, which are rarely considered by many researchers. The authors further improve the intelligent production technique and address this issue. Both methods proposed in this paper can be applied to embedded equipment, which can effectively improve steel strip factory production efficiency and reduce material and time loss.
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Peiwu Dong, Kai Qiao and Mei Yang
The purpose of this paper is to study the operational efficiency of aerospace industry in China and compare the difference in efficiency between the private aerospace enterprises…
Abstract
Purpose
The purpose of this paper is to study the operational efficiency of aerospace industry in China and compare the difference in efficiency between the private aerospace enterprises and the state-owned aerospace enterprises. This paper enriches the study on evaluating the operational efficiency of aerospace industry and develops the theory on aerospace industry management.
Design/methodology/approach
The sample comprises all the aerospace enterprises listed in the A share market for which financial data are collected from the RESSET for subsequent analysis. Data envelopment analysis (DEA) and Malmquist productivity index (MPI) are used to derive findings.
Findings
The paper finds both the scale and the technical level of the industry increased during the period, and this was mainly due to the growth of the state-owned enterprises. However, with the increase of scale, the total factor productivity of the sample decreased. This was mainly because the performance of the leading enterprises regressed. Overall, the operational efficiency of the industry was still relatively low. By comparing the private enterprises and the state-owned enterprises, this paper finds, in terms of scale, the private enterprises were far lower than the state-owned enterprises. However, as for operational efficiency, the private was more efficient, which indicates an imbalance in the development of the industry.
Originality/value
This paper explores the operational efficiency across the Chinese aerospace industry, a focus currently lacking in research, presenting an overview of the industry and examining the difference in efficiency between the private aerospace enterprises and the state-owned aerospace enterprises to provide policymakers and managers with some practical suggestions to promote the development of the industry.
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Wei Hou, Yitao Chen, Yunlong Dong, Xuanye Qin and Fei Miao
Through a lot of investigation, many times of demonstrating scheme, the in-depth theoretic analysis, a large scale numeric simulation tests and the field tests, the operating line…
Abstract
Through a lot of investigation, many times of demonstrating scheme, the in-depth theoretic analysis, a large scale numeric simulation tests and the field tests, the operating line of the rapid excavation is equipped which are consisting of the way of the drilling and blasting, the bolt-mesh-spurting supporting and the trackless transportation. The key technology which includes the stable technology of controling the surrounding rock, the optimization technology of transportation system, the excavating technology of layered drilling and the technology of parallel and cross operation develops the integral management framework and the advanced technology framework with the operating line, which realizes the safe and efficient construction and provides rich experience for the similar mines.
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Juan Chen, Hongling Guo and Zuoping Xiao
This study aims to investigate how high-speed railway (HSR) development affects urban construction investment (UCI) bond yield spreads based on China’s background.
Abstract
Purpose
This study aims to investigate how high-speed railway (HSR) development affects urban construction investment (UCI) bond yield spreads based on China’s background.
Design/methodology/approach
This study constructs a quasi-natural experiment and adopts regression analyses to empirically examine the relation between HSR development and UCI bond yield spreads. The empirical analysis is based on a Chinese sample of 15,109 bond offering observations from 2008 to 2019.
Findings
The results show that HSR development reduces UCI bond yield spreads. Mechanistic analysis shows that HSR development increases land prices and the level of urbanization, which in turn lowers the UCI bond yield spreads. In addition, the impact of HSR development on UCI bond yield spreads is more significant at higher marketization levels and lower degrees of dependence on land finance cities where UCI corporations are located.
Research limitations/implications
The results imply that transportation infrastructure improvement, such as HSR development, helps to enhance the credit of local governments and the solvency of UCI corporations and ultimately reduces the financing cost of UCI bonds.
Originality/value
This paper provides theoretical support and empirical evidence for the impact of transportation infrastructure construction on the implicit debt risks of local governments in China, which enriches the research on the “HSR economy” from a micro perspective and expands the research on the influencing factors of local governments’ debt risk.
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Qiongwei Ye and Baojun Ma
Internet + and Electronic Business in China is a comprehensive resource that provides insight and analysis into E-commerce in China and how it has revolutionized and continues to…
Abstract
Internet + and Electronic Business in China is a comprehensive resource that provides insight and analysis into E-commerce in China and how it has revolutionized and continues to revolutionize business and society. Split into four distinct sections, the book first lays out the theoretical foundations and fundamental concepts of E-Business before moving on to look at internet+ innovation models and their applications in different industries such as agriculture, finance and commerce. The book then provides a comprehensive analysis of E-business platforms and their applications in China before finishing with four comprehensive case studies of major E-business projects, providing readers with successful examples of implementing E-Business entrepreneurship projects.
Internet + and Electronic Business in China is a comprehensive resource that provides insights and analysis into how E-commerce has revolutionized and continues to revolutionize business and society in China.
Haiqing Hu and Tian Wu
Strengthening the combination of technology and finance can significantly promote the development of economy and society. Urbanization is a crucial standard to measure the…
Abstract
Strengthening the combination of technology and finance can significantly promote the development of economy and society. Urbanization is a crucial standard to measure the economic and social development of a country and region, and urban regional planning based on science and technology finance has always been the focus of both domestic and foreign research institutions. Thus, this paper takes Mianyang, the first city of science and technology, as the object of research, and from the angle of the development process of Mianyang, investigates the three stages of the construction and development of this science and technology city. This study analyzes the characteristics of regional planning of Mianyang City and sums up the idea of relying on the old city to build another new district, which boosts the development of science and technology as well as the economy. From two specific angles (i.e., urban spatial function region planning and urban and rural planning), this paper thoroughly studies a multiscale planning scheme of Mianyang’s urban area in recent years by researching the local policy, system, finance, and society. Empirical measurement proves that reasonable planning and construction of the science and technology city Mianyang can accelerate the development process of the western region, effectively promoting the economic development of the surrounding areas of Sichuan and remarkably improving the overall quality of the regional economy of both Chongqing and Sichuan Provinces.
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Debiao Meng, Peng Nie, Shiyuan Yang, Xiaoyan Su and Chengbo Liao
As a clean and renewable energy source, wind energy will become one of the main sources of new energy supply in the future. Relying on the stable and strong wind resources at sea…
Abstract
Purpose
As a clean and renewable energy source, wind energy will become one of the main sources of new energy supply in the future. Relying on the stable and strong wind resources at sea, wind energy has great potential to become the primary energy. As a critical part of the wind turbine, the gearbox of a wind turbine often bears a large external load. Especially at sea, due to the effects of ocean corrosion, waves and wind, the burden of the wind turbine gearbox is greater, which brings great challenges to its reliability analysis. This study aims to systematically review the reliability research in wind turbine gearboxes and guide future research directions and challenges.
Design/methodology/approach
This study systematically reviews some design requirements and reliability analysis methods for wind turbine gearboxes. Then, it summarizes previous studies on wind load uncertainty modeling methods, including the processing of wind measurement data and the summary of three different classifications of random wind speed prediction models. Finally, existing reliability analysis studies on two major parts of the gearbox are described and summarized.
Findings
First, the basic knowledge of wind turbine gearboxes and their reliability analysis is introduced. The requirements and reliability analysis methods of wind turbine gearboxes are explained. Then, the processing methods of wind measurement data and three different random wind speed prediction models are described in detail. Furthermore, existing reliability analysis studies on two common parts of wind turbine gearboxes, gears and bearings, are summarized and classified, including a summary of bearing failure modes. Finally, three possible future research directions for wind turbine gearbox reliability analysis are discussed, namely, reliability research under the influence of multiple factors on gears, damage indicators of bearing failure modes and quantitative evaluation criteria for the overall dynamic characteristics of offshore wind turbine gearboxes and a summary is also given.
Originality/value
This paper aims to systematically introduce the relevant contents of wind turbine gearboxes and their reliability analysis. The contents of wind speed data processing, predictive modeling and reliability analysis of major components are also comprehensively reviewed, including the classification and principle introduction of these contents.
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Huaxiang Song, Hanjun Xia, Wenhui Wang, Yang Zhou, Wanbo Liu, Qun Liu and Jinling Liu
Vision transformers (ViT) detectors excel in processing natural images. However, when processing remote sensing images (RSIs), ViT methods generally exhibit inferior accuracy…
Abstract
Purpose
Vision transformers (ViT) detectors excel in processing natural images. However, when processing remote sensing images (RSIs), ViT methods generally exhibit inferior accuracy compared to approaches based on convolutional neural networks (CNNs). Recently, researchers have proposed various structural optimization strategies to enhance the performance of ViT detectors, but the progress has been insignificant. We contend that the frequent scarcity of RSI samples is the primary cause of this problem, and model modifications alone cannot solve it.
Design/methodology/approach
To address this, we introduce a faster RCNN-based approach, termed QAGA-Net, which significantly enhances the performance of ViT detectors in RSI recognition. Initially, we propose a novel quantitative augmentation learning (QAL) strategy to address the sparse data distribution in RSIs. This strategy is integrated as the QAL module, a plug-and-play component active exclusively during the model’s training phase. Subsequently, we enhanced the feature pyramid network (FPN) by introducing two efficient modules: a global attention (GA) module to model long-range feature dependencies and enhance multi-scale information fusion, and an efficient pooling (EP) module to optimize the model’s capability to understand both high and low frequency information. Importantly, QAGA-Net has a compact model size and achieves a balance between computational efficiency and accuracy.
Findings
We verified the performance of QAGA-Net by using two different efficient ViT models as the detector’s backbone. Extensive experiments on the NWPU-10 and DIOR20 datasets demonstrate that QAGA-Net achieves superior accuracy compared to 23 other ViT or CNN methods in the literature. Specifically, QAGA-Net shows an increase in mAP by 2.1% or 2.6% on the challenging DIOR20 dataset when compared to the top-ranked CNN or ViT detectors, respectively.
Originality/value
This paper highlights the impact of sparse data distribution on ViT detection performance. To address this, we introduce a fundamentally data-driven approach: the QAL module. Additionally, we introduced two efficient modules to enhance the performance of FPN. More importantly, our strategy has the potential to collaborate with other ViT detectors, as the proposed method does not require any structural modifications to the ViT backbone.
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Indrajeet Katti, Alistair Jones, Matthias Weiss, Dong Qiu, Joy H. Forsmark and Mark Easton
Powder bed fusion-laser beam (PBF-LB) is a rapidly growing manufacturing technology for producing Al-Si alloys. This technology can be used to produce high-pressure die-casting…
Abstract
Purpose
Powder bed fusion-laser beam (PBF-LB) is a rapidly growing manufacturing technology for producing Al-Si alloys. This technology can be used to produce high-pressure die-casting (HPDC) prototypes. The purpose of this paper is to understand the similarities and differences in the microstructures and properties of PBF-LB and HPDC alloys.
Design/methodology/approach
PBF-LB AlSi10Mg and HPDC AlSi10Mn plates with different thicknesses were manufactured. Iso-thermal heat treatment was conducted on PBF-LB bending plates. A detailed meso-micro-nanostructure analysis was performed. Tensile, bending and microhardness tests were conducted on both alloys.
Findings
The PBF-LB skin was highly textured and softer than its core, opposite to what is observed in the HPDC alloy. Increasing sample thickness increased the bulk strength for the PBF-LB alloy, contrasting with the decrease for the HPDC alloy. In addition, the tolerance to fracture initiation during bending deformation is greater for the HPDC material, probably due to its stronger skin region.
Practical implications
This knowledge is crucial to understand how geometry of parts may affect the properties of PBF-LB components. In particular, understanding the role of geometry is important when using PBF-LB as a HPDC prototype.
Originality/value
This is the first comprehensive meso-micro-nanostructure comparison of both PBF-LB and HPDC alloys from the millimetre to nanometre scale reported to date that also considers variations in the skin versus core microstructure and mechanical properties.
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Zhongkai Shen, Shaojun Li, Zhenpeng Wu, Bowen Dong, Wenyan Luo and Liangcai Zeng
This study aims to investigate the effects of irregular groove textures on the friction and wear performance of sliding contact surfaces. These textures possess multiple depths…
Abstract
Purpose
This study aims to investigate the effects of irregular groove textures on the friction and wear performance of sliding contact surfaces. These textures possess multiple depths and asymmetrical features. To optimize the irregular groove texture structure of the sliding contact surface, an adaptive genetic algorithm was used for research and optimization purposes.
Design/methodology/approach
Using adaptive genetic algorithm as an optimization tool, numerical simulations were conducted on surface textures by establishing a dimensionless form of the Reynolds equation and setting appropriate boundary conditions. An adaptive genetic algorithm program in MATLAB was established. Genetic iterative methods were used to calculate the optimal texture structure. Genetic individuals were selected through fitness comparison. The depth of the groove texture is gradually adjusted through genetic crossover, mutation, and mutation operations. The optimal groove structure was ultimately obtained by comparing the bearing capacity and pressure of different generations of micro-convex bodies.
Findings
After about 100 generations of iteration, the distribution of grooved textures became relatively stable, and after about 320 generations, the depth and distribution of groove textures reached their optimal structure. At this stage, irregular texture structures can support more loads by forming oil films. Compared with regular textures, the friction coefficient of irregular textures decreased by nearly 47.01%, while the carrying capacity of lubricating oil films increased by 54.57%. The research results show that irregular texture structures have better lubrication characteristics and can effectively improve the friction performance of component surfaces.
Originality/value
Surface textures can enhance the friction and lubrication performance of metal surfaces, improving the mechanical performance and lifespan of components. However, surface texture processing is challenging, as it often requires multiple experimental comparisons to determine the optimal texture structure, resulting in high trial-and-error costs. By using an adaptive genetic algorithm as an optimization tool, the optimal surface groove structure can be obtained through simulation and modeling, effectively saving costs in the process.