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Editorial for the Special Issue on Emerging Technology and Advanced Application of Nondestructive Detection for Power Equipment

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Chinese j.urnal of Electrical Engineering 2024年第1期10卷 1-2页

作者： Li j. Mei H. Li S. Tianj.n University China Tsinghua Shenzhen International Graduate School China Lanzhou j.aotong University China

The rapid development of clean and renewable energy technologies represented by wind and solar energy,as well as the continuous growth of load demand,have put forward higher requirements for the safe operation of the power *** performance of power equipment based on traditional dielectric materials is often limited by various defects generated during molding,transportation,assembly,and operation,which cannot meet the reliability requirements of power systems in the new *** detection is an essential technical method in industrial development,which can detect and evaluate the defect and damage status of in-service equipment,key components,and materials without damaging the obj.ct.

关键词： service Application operation

Demand-Responsive Transportation Vehicle Routing Optimization Based on Two-Stage Method

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Computers, Materials and Continua 2024年第1期81卷 443-469页

作者： Ma j. Liu H. Chen L. School of Railway Transportation Shanghai Institute of Technology Shanghai 201418 China

Demand-responsive transportation (DRT) is a flexible passenger service designed to enhance road efficiency, reduce peak-hour traffic, and boost passenger satisfaction. However, existing optimization methods for initial passenger requests fall short in addressing real-time passenger needs. Consequently, there is a need to develop real-time DRT route optimization methods that integrate both initial and real-time requests. This paper presents a two-stage, multi-obj.ctive optimization model for DRT vehicle scheduling. The first stage involves an initial scheduling model aimed at minimizing vehicle configuration, and operational, and CO2 emission costs while ensuring passenger satisfaction. The second stage develops a real-time scheduling model to minimize additional operational costs, penalties for time window violations, and costs due to rej.cted passengers, thereby addressing real-time demands. Additionally, an enhanced genetic algorithm based on Non-dominated Sorting Genetic Algorithm-II (NSGA-II) is designed, incorporating multiple crossover points to accelerate convergence and improve solution efficiency. The proposed scheduling model is validated using a real network in Shanghai. Results indicate that real-time scheduling can serve more passengers, and improve vehicle utilization and occupancy rates, with only a minor increase in total operational costs. Compared to the traditional NSGA-II algorithm, the improved version enhances convergence speed by 31.7% and solution speed by 4.8%. The proposed model and algorithm offer both theoretical and practical guidance for real-world DRT scheduling. © 2024 The Authors.

关键词： artificial intelligence applications Demand responsive transit genetic algorithm muti-obj.ctive optimization

A Facial Expression Recognition Method Integrating Uncertainty Estimation and Active Learning

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Computers, Materials and Continua 2024年第1期81卷 533-548页

作者： Wang Y. Zhang j. Sun R. School of Computer Science and Engineering Chongqing University of Technology Chongqing 400054 China Data Space Research Institute of Hefei Comprehensive National Science Center Hefei 230088 China

The effectiveness of facial expression recognition (FER) algorithms hinges on the model’s quality and the availability of a substantial amount of labeled expression data. However, labeling large datasets demands significant human, time, and financial resources. Although active learning methods have mitigated the dependency on extensive labeled data, a cold-start problem persists in small to medium-sized expression recognition datasets. This issue arises because the initial labeled data often fails to represent the full spectrum of facial expression characteristics. This paper introduces an active learning approach that integrates uncertainty estimation, aiming to improve the precision of facial expression recognition regardless of dataset scale variations. The method is divided into two primary phases. First, the model undergoes self-supervised pre-training using contrastive learning and uncertainty estimation to bolster its feature extraction capabilities. Second, the model is fine-tuned using the prior knowledge obtained from the pre-training phase to significantly improve recognition accuracy. In the pre-training phase, the model employs contrastive learning to extract fundamental feature representations from the complete unlabeled dataset. These features are then weighted through a self-attention mechanism with rank regularization. Subsequently, data from the low-weighted set is relabeled to further refine the model’s feature extraction ability. The pre-trained model is then utilized in active learning to select and label information-rich samples more efficiently. Experimental results demonstrate that the proposed method significantly outperforms existing approaches, achieving an improvement in recognition accuracy of 5.09% and 3.82% over the best existing active learning methods, Margin, and Least Confidence methods, respectively, and a 1.61% improvement compared to the conventional segmented active learning method. © 2024 The Authors.

关键词： active learning Expression recognition self-supervised learning uncertainty estimation

Helicobacter pylori infection may result in poor gastric cleanliness in magnetically controlled capsule gastroscopy examination: A single-center retrospective study

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Laparoscopic, Endoscopic, and Robotic Surgery 2024年第4期7卷 147-154页

作者： Xia j. Fang j. Chen L. Meng Y. Su L. Department of General Practice Sir Run Run Shaw Hospital Zhejiang University School of Medicine Hangzhou 310016 China

Obj.ctive: Magnetically controlled capsule gastroscopy (MCCG) is an effective method for screening gastric diseases; however, its performance may be affected by gastric cleanliness. We aimed to explore the correlation between Helicobacter pylori infection and the degree of gastric cleanliness in the MCCG. Methods: This retrospective study enrolled 297 participants from October 2020 to April 2024 at Sir Run Run Shaw Hospital, Zhej.ang University School of Medicine. Participant characteristics, MCCG examination results, and (13) C-urea breath test (C13-UBT) results were collected. The gastric cleanliness in MCCG examinations was assessed using a gastric cleanliness score. Binary logistic regression was used to analyze the relationships among participant characteristics, H. pylori infection, and gastric cleanliness. Chi-square tests and Fisher's exact tests were used to analyze the relationships among gastric lesions, H. pylori infection, and gastric cleanliness. Results: Among the participants, 24.2% had H. pylori infection, and 17.5% had poor gastric cleanliness. Hypertension (odds ratio [OR]: 2.63; 95% confidence interval [CI]: 1.36–5.09; p = 0.004) was associated with a greater likelihood of H. pylori infection. H. pylori infection (OR: 3.76; 95% CI: 1.99–7.09; p < 0.001) was an independent risk factor for poor gastric cleanliness in the MCCG. A significant disparity was noted in the prevalence of focal erosions (p < 0.001), gastric ulcers (p = 0.001), and positive gastric lesions (p = 0.027) between the 2 groups with and without H. pylori infection. The proportion of positive gastric lesions was not significantly different between the good gastric cleanliness group and the poor gastric cleanliness group (25.7% vs. 21.2%; p = 0.490). Conclusion: The findings of this study revealed that H. pylori infection was associated with hypertension. H. pylori infection may lead to poor gastric cleanliness. Institutions are advised to perform C13-UBT before MCCG, and participa

关键词： C-urea breath test Gastric cleanliness Helicobacter pylori Hypertension Magnetically controlled capsule gastroscopy

Risk of Tropical Cyclones and Floods to Power Grids in Southeast and East Asia

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INTERNATIONAL j.URNAL OF DISASTER RISK SCIENCE 2024年第4期15卷 494-507页

作者： Ye, Mengqi Ward, Philip j. Bloemendaal, Nadia Nirandj.n, Sadhana Koks, Elco E. Vrij. Univ Amsterdam Inst Environm Studies NL-1081 HV Amsterdam Netherlands Deltares NL-2629 HV Delft Netherlands Royal Netherlands Meteorol Inst KNMI NL-3731 GA De Bilt Netherlands

Power grids play a critical role in modern society, serving as the lifeline of a well-functioning economy. This article presents a first large-scale study on the risk estimation of tropical cyclone (TC)-induced winds and coastal floods, which can widely impact power grids in Southeast and East Asia. Our comprehensive risk model incorporates detailed infrastructure data from OpenStreetMap (OSM) and government power grid maps, along with global hazard maps and vulnerability curves. The results reveal that the estimated expected annual damages from TCs and coastal floods to OSM-mapped assets account for approximately 0.07% (0.00-0.38%) and 0.02% (0.00-0.02%) of the total GDP of the study area, respectively. We analyzed the main sources of uncertainty in the risk model and emphasized the importance of understanding asset vulnerability. These results highlight the urgent need to strengthen power infrastructure to withstand the impacts of natural hazards, and the significance of reliable risk information for improving power grid design and planning. Focusing on developing more region-specific infrastructure data and vulnerability curves will improve the accuracy of risk estimation and provide valuable insights not only for the electricity sector but also for customers of other infrastructure systems that heavily rely on a stable supply of electricity.

关键词： Asset level Coastal floods Power grids Risk analysis Tropical cyclones Vulnerability curves DAMAGE INFRASTRUCTURE ADAPTATION FRAMEWORK IMPACTS SYSTEMS COSTS

Assessing the Impact of Catastrophic Electricity Loss on the Food Supply Chain

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INTERNATIONAL j.URNAL OF DISASTER RISK SCIENCE 2024年第4期15卷 481-493页

作者： Blouin, Simon Herwix, Alexander Rivers, Morgan Tieman, Ross j. Denkenberger, David C. Alliance Feed Earth Disasters ALLFED Lafayette CO 80026 USA Univ Canterbury Dept Mech Engn Christchurch 8041 New Zealand Univ Cologne Cologne Inst Informat Syst D-50969 Cologne Germany

The food supply chain's heavy reliance on electricity poses significant vulnerabilities in the event of prolonged and widespread power disruptions. This study introduces a system-dynamics model that integrates five critical infrastructures-electric grid, liquid fossil fuels, Internet, transportation, and human workforce-to evaluate the resilience of food supply chains to maj.r power outages. We validated the model using the 2019 Venezuelan blackouts as a case study, demonstrating its predictive validity. We then explored how more extreme electricity losses would disrupt the supply chain. More specifically, we modeled the impact of a large-scale cyberattack on the US electric grid and a high-altitude electromagnetic pulse (HEMP) event. A cyberattack severely damaging the US electric grid and allowing for recovery within a few weeks or months would lead to substantial drops in food consumption. However, it would likely still be possible to provide adequate calories to everyone, assuming that food is equitably distributed. In contrast, a year-long recovery from a HEMP event affecting most of the continental United States could precipitate a state of famine. Our analysis represents a first attempt at quantifying how food availability progressively worsens as power outages extend over time. Our open-source model is made publicly available, and we encourage its application to other catastrophic scenarios beyond those specifically considered in this work (for example, extreme solar storms, high-lethality pandemics).

关键词： Cyberattack Electricity Food supply chains Global catastrophic risk High-altitude electromagnetic pulse System dynamics

A DiscreteMulti-Obj.ctive Squirrel Search Algorithm for Energy-Efficient Distributed Heterogeneous Permutation Flowshop with Variable Processing Speed

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Computers, Materials and Continua 2024年第1期81卷 1757-1787页

作者： Zeng L. Ding Z. Shi j. Wang S. School of Electrical and Electronic Engineering Hubei University of Technology Wuhan 430068 China Hubei Key Laboratory for High-Efficiency Utilization of Solar Energy and Operation Control of Energy Storage System Hubei University of Technology Wuhan 430068 China Xiangyang Industrial Institute of Hubei University of Technology Xiangyang 441100 China

In the manufacturing industry, reasonable scheduling can greatly improve production efficiency, while excessive resource consumption highlights the growing significance of energy conservation in production. This paper studies the problem of energy-efficient distributed heterogeneous permutation flowshop problem with variable processing speed (DHPFSP-VPS), considering both theminimum makespan and total energy consumption (TEC) as obj.ctives. A discrete multi-obj.ctive squirrel search algorithm (DMSSA) is proposed to solve the DHPFSPVPS. DMSSA makes four improvements based on the squirrel search algorithm. Firstly, in terms of the population initialization strategy, four hybrid initialization methods targeting different obj.ctives are proposed to enhance the quality of initial solutions. Secondly, enhancements are made to the population hierarchy system and position updating methods of the squirrel search algorithm, making it more suitable for discrete scheduling problems. Additionally, regarding the search strategy, six local searches are designed based on problem characteristics to enhance search capability. Moreover, a dynamic predator strategy based on Q-learning is devised to effectively balanceDMSSA's capability for global exploration and local exploitation. Finally, two speed control energy-efficient strategies are designed to reduce TEC. Extensive comparative experiments are conducted in this paper to validate the effectiveness of the proposed strategies. The results of comparing DMSSA with other algorithms demonstrate its superior performance and its potential for efficient solving of the DHPFSP-VPS problem. © 2024 The Authors. Published by Tech Science Press.

关键词： Distributed heterogeneous permutation flowshop problem energy-efficient squirrel search algorithm muli-obj.ctive optimization variable processing speed

Improved Harris Hawks Algorithm and Its Application in Feature Selection

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Computers, Materials and Continua 2024年第1期81卷 1251-1273页

作者： Zhang Q. Li Y. Zhan j. Chen S. School of Computer Science and Information Engineering Harbin Normal University Harbin 150025 China College of Systems Engineering National University of Defense Technology Changsha 410073 China

This research focuses on improving the Harris' Hawks Optimization algorithm (HHO) by tackling several of its shortcomings, including insufficient population diversity, an imbalance in exploration vs. exploitation, and a lack of thorough exploitation depth. To tackle these shortcomings, it proposes enhancements from three distinct perspectives: an initialization technique for populations grounded in opposition-based learning, a strategy for updating escape energy factors to improve the equilibrium between exploitation and exploration, and a comprehensive exploitation approach that utilizes variable neighborhood search along with mutation operators. The effectiveness of the Improved Harris Hawks Optimization algorithm (IHHO) is assessed by comparing it to five leading algorithms across 23 benchmark test functions. Experimental findings indicate that the IHHO surpasses several contemporary algorithms its problem-solving capabilities. Additionally, this paper introduces a feature selection method leveraging the IHHOalgorithm(IHHO-FS) to address challenges such as lowefficiency in feature selection and high computational costs (time to find the optimal feature combination and model response time) associated with high-dimensional datasets. Comparative analyses between IHHO-FS and six other advanced feature selection methods are conducted across eight datasets. The results demonstrate that IHHO-FS significantly reduces the computational costs associated with classification models by lowering data dimensionality, while also enhancing the efficiency of feature selection. Furthermore, IHHO-FS shows strong competitiveness relative to numerous algorithms. © 2024 The Authors. Published by Tech Science Press.

关键词： deep exploitation strategy energy factor update strategy feature selection HHO IHHO population diversity

Paraelectric Doping Simultaneously Improves the Field Frequency Adaptability and Dielectric Properties of Ferroelectric Materials: A Phase-Field Study

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Computers, Materials and Continua 2024年第1期81卷 213-228页

作者： Wang Z. Cao j. Liu Z. Zhao Y. School of Materials Science and Engineering Collaborative Innovation Center of Ministry of Education and Shanxi Province for High-Performance Al/Mg Alloy Materials North University of China Taiyuan 030051 China Beij.ng Advanced Innovation Center for Materials Genome Engineering University of Science and Technology Beijing Beijing 100083 China Institute of Materials Intelligent Technology Liaoning Academy of Materials Shenyang 110004 China

Recent years, the polarization response of ferroelectrics has been entirely studied. However, it is found that the polarization may disappear gradually with the continually applied of electric field. In this paper, taking K0.48Na0.52NbO3(KNN) as an example, it was demonstrated that the residual polarization began to decrease when the electric field frequency increased to a certain extent using a phase-field methods. The results showed that the content of out-of-plane domains increased first and then decreased with the increase of applied electric field frequency, the maximum polarization disappeared at high frequencies, and the hysteresis loop became elliptical. In order to further study the abnormal changes of hysteresis loops of ferroelectrics under high electric field frequency, we analyzed the hysteresis loop and dielectric response of solid solution 0.1SrTiO3-0.9K0.48Na0.52NbO3. It was found that the doped hysteresis loop maintained its shape at higher frequency and the dielectric constant increased. This kind of doping has a higher field frequency adaptability, which has a key guiding role in improving the dielectric properties of ferroelectric thin films and expanding the frequency application range of ferroelectric nano memory. © 2024 The Authors. Published by Tech Science Press.

关键词： dielectric properties doping electric field frequency Ferroelectric ceramics phase field method