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China Ocean engineering 2024年第2期38卷 198-209页

作者： WU Qi-bing CAI Bao-ping FAN Hong-yan WANG Guan-nan RAO Xi GE Weifeng SHAO Xiao-yan LIU Yong-hong CNOOC Safety Technology services Co. Ltd.Tianjin 300456China College of Mechanical and Electronic engineering China University of PetroleumQingdao 266580China CNOOC EnerTech Safety&Environmental Protection BranchTianjin 300456China

Maintenance is an important technical measure to maintain and restore the performance status of equipment and ensure the safety of the production process in industrial production,and is an indispensable part of prediction and health ***,most of the existing remaining useful life(RUL)prediction methods assume that there is no maintenance or only perfect maintenance during the whole life cycle;thus,the predicted RUL value of the system is obviously lower than its actual operating *** complex environment of the system further increases the difficulty of maintenance,and its maintenance nodes and maintenance degree are limited by the construction period and working conditions,which increases the difficulty of RUL *** RUL prediction method for a multi-omponent system based on the Wiener process considering maintenance is *** performance degradation model of components is established by a dynamic Bayesian network as the initial model,which solves the uncertainty of insufficient data *** on the experience of experts,the degree of degradation is divided according to Poisson process simulation random failure,and different maintenance strategies are used to estimate a variety of condition maintenance *** example of a subsea tree system is given to verify the effectiveness of the proposed method.

关键词： remaining useful life Wiener process dynamic Bayesian networks maintenance subsea Christmas tree system

Service Function Chain Deployment Algorithm Based on Multi-Agent Deep Reinforcement Learning

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Computers, Materials & Continua 2024年第9期80卷 4875-4893页

作者： Wanwei Huang Qiancheng Zhang Tao Liu YaoliXu Dalei Zhang College of Software engineering Zhengzhou University of Light IndustryZhengzhou450007China Henan Jiuyu Tenglong Information engineering Co. Ltd.Zhengzhou450052China Henan Xin’an Communication Technology Co. Ltd.Zhengzhou450007China

Aiming at the rapid growth of network services,which leads to the problems of long service request processing time and high deployment cost in the deployment of network function virtualization service function chain(SFC)under 5G networks,this paper proposes a multi-agent deep deterministic policy gradient optimization algorithm for SFC deployment(MADDPG-SD).Initially,an optimization model is devised to enhance the request acceptance rate,minimizing the latency and deploying the cost SFC is constructed for the network resource-constrained ***,we model the dynamic problem as a Markov decision process(MDP),facilitating adaptation to the evolving states of network ***,by allocating SFCs to different agents and adopting a collaborative deployment strategy,each agent aims to maximize the request acceptance rate or minimize latency and *** agents learn strategies from historical data of virtual network functions in SFCs to guide server node selection,and achieve approximately optimal SFC deployment strategies through a cooperative framework of centralized training and distributed *** simulation results indicate that the proposed method,while simultaneously meeting performance requirements and resource capacity constraints,has effectively increased the acceptance rate of requests compared to the comparative algorithms,reducing the end-to-end latency by 4.942%and the deployment cost by 8.045%.

关键词： Network function virtualization service function chain Markov decision process multi-agent reinforcement learning

System design and validation of Queqiao-2 lunar relay communication satellite

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中国空间科学技术(中英文) 2024年第05期 23-39页

作者： ZHANG Lihua XIONG Liang SUN Ji CHEN Luojing XIAO Chuan ZHOU Wenyan WANG Yong LIU Wangwang GUAN Yifeng CHEN Tao YU Xiaochuan XU Jin CHEN Guohui CAO Xiaoping DFH Satellite Co. Ltd. Beijing Institute of Spacecraft System engineering Beijing Institute of Control engineering Academy of Space Information Systems

In order to provide relay communication supports for future Chinese lunar exploration program, Queqiao-2 relay communication satellite was ***-2 can perform scientific observations with three kinds of scientific instruments on *** system design of Queqiao-2,including mission orbit and transfer orbit design, configuration and layout design, housekeeping and information flow design, power supply and distribution design, GNC and propulsion system design, communication links design, etc.,was accomplished through comprehensive tradeoff and evaluation on technical maturity, availability, schedule, cost, and so *** a view to reducing development risk, both the platform and relay communication payloads were developed based on significant heritage from previous Queqiao relay satellite and other relevant ***-2 features flexible system architecture to support multiple frequencies, modulations, data rates and software reconfigurations to meet new user *** to a successful launch on March 20,2024,by means of 5 orbit maneuvers, Queqiao-2 was inserted into a highly elliptical frozen mission orbit around the moon with a 24h period on *** on-orbit tests and calibrations, Queqiao-2 has possessed the capacity to provide reliable relay communication services to multiple lunar exploration missions, as well as the capacity to perform scientific *** the support of Queqiao-2,Chang′e-6 achieved its ambitious mission goal to collect and return samples from the moon′s mysterious far *** the meanwhile, Queqiao-2 has also paved the way for the following Chinese lunar exploration missions including Chang′e-7 and Chang′*** design life time of Queqiao-2 is more than 8 *** from flexibility and extensibility of relay communication system design, it is convenient to provide relay communication services for future lunar exploration missions of both China and other *** addition, innovative

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Reliable Data Collection Model and Transmission Framework in Large-Scale Wireless Medical Sensor Networks

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Computer Modeling in engineering & Sciences 2024年第7期140卷 1077-1102页

作者： Haosong Gou Gaoyi Zhang RenêRipardo Calixto Senthil Kumar Jagatheesaperumal Victor Hugo C.de Albuquerque China Mobile Group Sichuan Co. Ltd.Chengdu640041China Department of Teleinformatics engineering Federal University of CearáFortaleza60455-970Brazil Department of Electronics&Communication engineering Mepco Schlenk Engineering CollegeSivakasi626005India

Large-scale wireless sensor networks(WSNs)play a critical role in monitoring dangerous scenarios and responding to medical ***,the inherent instability and error-prone nature of wireless links present significant challenges,necessitating efficient data collection and reliable transmission *** paper addresses the limitations of existing data transmission and recovery protocols by proposing a systematic end-to-end design tailored for medical event-driven cluster-based large-scale *** primary goal is to enhance the reliability of data collection and transmission services,ensuring a comprehensive and practical *** approach focuses on refining the hop-count-based routing scheme to achieve fairness in forwarding ***,it emphasizes reliable data collection within clusters and establishes robust data transmission over multiple *** systematic improvements are designed to optimize the overall performance of the WSN in real-world *** results of the proposed protocol validate its exceptional performance compared to other prominent data transmission *** evaluation spans varying sensor densities,wireless channel conditions,and packet transmission rates,showcasing the protocol’s superiority in ensuring reliable and efficient data *** systematic end-to-end design successfully addresses the challenges posed by the instability of wireless links in *** prioritizing fairness,reliability,and efficiency,the proposed protocol demonstrates its efficacy in enhancing data collection and transmission services,thereby offering a valuable contribution to the field of medical event-drivenWSNs.

关键词： Wireless sensor networks reliable data transmission medical emergencies cluster data collection routing scheme

Spatio-temporal evolution analysis of landscape pattern and habitat quality in the Qinghai Province section of the Yellow River Basin from 2000 to 2022 based on InVEST model

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Journal of Arid Land 2024年第9期16卷 1183-1196页

作者： ZHENG Guoqiang Li Cunxiu LI Runjie LUO Jing FAN Chunxia ZHU Hailing College of Geography Qinghai Normal UniversityXining 810008China Qinghai engineering Consulting Center Co. Ltd.Xining 810001China Qinghai University Xining 810016China

Habitat quality is an important indicator for evaluating the quality of *** Qinghai Province section of the Yellow River Basin plays an important role in the ecological protection of the upper reaches of the Yellow River *** comprehensively analysis the alterations of habitat quality in the Qinghai Province section of the Yellow River Basin,this study utilized the Integrated Valuation of Ecosystem services and Tradeoffs(InVEST)model to calculate the habitat quality index and analyze the spatio-temporal variation characteristics of habitat quality in the study area from 2000 to 2022,and calculated seven landscape pattern indices(number of patches,patch density,largest patch index(LPI),landscape shape index(LSI),contagion index(CONTAG),Shannon diversity index,and Shannon evenness index)to research the variation of landscape pattern in the study *** results showed that the number of patches,patch density,LPI,LSI,Shannon diversity index,and Shannon evenness index increased from 2000 to 2022,while the CONTAG decreased,indicating that the landscape pattern in the Qinghai Province section of the Yellow River Basin changed in the direction of distribution fragmentation,shape complexity,and *** average value of the habitat quality index in the Qinghai Province section of the Yellow River Basin from 2000 to 2022 was *** on the value of habitat quality index,we divided the level of habitat quality into five categories:lower(0.00-0.20),low(0.20-0.40),moderate(0.40-0.60),high(0.60-0.80),and higher(0.80-1.00).Most areas were at the higher habitat quality *** lower habitat quality patches were mainly distributed in Longyang Gorge and Yellow River-Huangshui River *** 2000 to 2022,the habitat quality in most areas was stable;the increase areas were mainly distributed in Guinan County,while the decrease areas were mainly distributed in Xining City,Maqen County,Xinghai County,Qumarleb County,and Darlag *** show the extent of

关键词： InVEST model landscape pattern index habitat quality largest patch index landscape shape index Shannon evenness index

Spatiotemporal variations in ecosystem services and their trade-offs and synergies against the background of the gully control and land consolidation project on the Loess Plateau,China

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Journal of Arid Land 2024年第1期16卷 131-145页

作者： WANG Jing WEI Yulu PENG Biao LIU Siqi LI Jianfeng Key Laboratory of Degraded and Unused Land Consolidation engineering Ministry of Natural and ResourcesXi'an 710075China Institute of Land engineering and Technology Shaanxi Provincial Land Engineering Construction Group Co.Ltd.Xi'an 710021China School of Human Settlements and Civil engineering Xi'an Jiaotong UniversityXi'an 710049China Shaanxi Key Laboratory of Land Consolidation Xi'an 710064China

Studying the spatiotemporal variations in ecosystem services and their interrelationships on the Loess Plateau against the background of the gully control and land consolidation(GCLC)project has significant implications for ecological protection and quality development of the Yellow River ***,in this study,we took Yan'an City,Shaanxi Province of China,as the study area,selected four typical ecosystem services,including soil conservation service,water yield service,carbon storage service,and habitat quality service,and quantitatively evaluated the spatiotemporal variation characteristics and trade-offs and synergies of ecosystem services from 2010 to 2018 using the Integrated Valuation of Ecosystem services and Trade-offs(InVEST)*** also analysed the relationship between the GCLC project and regional ecosystem service changes in various regions(including 1 city,2 districts,and 10 counties)of Yan'an City and proposed a coordinated development strategy between the GCLC project and the ecological *** results showed that,from 2010 to 2018,soil conservation service decreased by 7.76%,while the other three ecosystem services changed relatively little,with water yield service increasing by 0.56% and carbon storage service and habitat quality service decreasing by 0.16% and 0.14%,*** ecological environment of Yan'an City developed in a balanced way between 2010 and 2018,and the four ecosystem services showed synergistic relationships,among which the synergistic relationships between soil conservation service and water yield service and between carbon storage service and habitat quality service were *** GCLC project had a negative impact on the ecosystem services of Yan'an City,and the impact on carbon storage service was more *** study provides a theoretical basis for the scientific evaluation of the ecological benefits of the GCLC project and the realization of a win-win situation between food security and e

关键词： ecosystem services trade-offs and synergies gully control and land consolidation habitat quality Integrated Valuation of Ecosystem services and Trade-offs(InVEST)model Loess Plateau

The joint knowledge reasoning model based on knowledge representation learning for aviation assembly domain

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Science China(Technological Sciences) 2024年第1期67卷 143-156页

作者： LIU PeiFeng QIAN Lu LU Hu XUE Lei ZHAO XingWei TAO Bo State Key Laboratory of Digital Manufacturing Equipment and Technology Department of MechanicalHuazhong University of Science and TechnologyWuhan 430074China School of Transportation and Logistics engineering Wuhan University of Technology(WHUT)Wuhan 430063China Shanghai Aircraft Manufacturing Co. Ltd.Shanghai 201324China

Knowledge graph technology is widely applied in the domain of general knowledge reasoning with an excellent *** fine-grained professional fields,professional knowledge graphs can provide more accurate information in practical industrial *** on an aviation assembly domain-specific knowledge graph,the article constructs a joint knowledge reasoning model,which combines a named entity recognition model and a subgraph embedding learning *** performing knowledge reasoning tasks,the two models vectorize entities,relationships and entity attributes in the same space,so as to share parameters and optimize learning *** knowledge reasoning model,which provides intelligent question answering services,is able to reduce the assembly error rate and improve the assembly *** system can accurately solve general knowledge reasoning problems in the assembly process in actual industrial scenarios of general assembly and component assembly under interference-free ***,this paper compares the proposed knowledge reasoning model based on knowledge representation learning and the question-answering system based on large-scale pre-trained *** the application scenario of system functional testing in general assembly,the joint model attains an accuracy rate of 95%,outperforming GPT with 78%accuracy and enhanced representation through knowledge integration with 71%accuracy.

关键词： intelligent manufacturing knowledge graph aviation assembly knowledge representation knowledge-based question an-swering

A Fuzzy Logic Based Supervisory Hierarchical Control Scheme for Real Time Pressure Control

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International Journal of Automation and computing 2009年第1期6卷 88-96页

作者： N. Kanagaraj P. Sivashanmugam S. Paramasivam Department of Chemical engineering National Institute of Technology esab engineering services ltd.

This paper describes a supervisory hierarchical fuzzy controller （SHFC） for regulating pressure in a real-time pilot pressure control system. The input scaling factor tuning of a direct expert controller is made using the error and process input parameters in a closed loop system in order to obtain better controller performance for set-point change and load disturbances. This on-line tuning method reduces operator involvement and enhances the controller performance to a wide operating range. The hierarchical control scheme consists of an intelligent upper level supervisory fuzzy controller and a lower level direct fuzzy controller. The upper level controller provides a mechanism to the main goal of the system and the lower level controller delivers the solutions to a particular situation. The control algorithm for the proposed scheme has been developed and tested using an ARM7 microcontroller-based embedded target board for a nonlinear pressure process having dead time. To demonstrate the effectiveness, the results of the proposed hierarchical controller, fuzzy controller and conventional proportional-integral （PI） controller are analyzed. The results prove that the SHFC performance is better in terms of stability and robustness than the conventional control methods.

关键词： Pressure control supervisory hierarchical fuzzy controller (SHFC) fuzzy controller ARM7 processor embedded controller

Enhancing Enterprise Efficiency through Cross-Domain Supply Chain Linkage Management

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Proceedings of Business and Economic Studies 2024年第4期7卷 99-104页

作者： Hui Zhao China Railway engineering Equipment Group Co. Ltd.Zhengzhou 450016China

In recent years,with the complexity and variability of international finance,debt,and geopolitical risks,the growth rate of domestic economic operations has slowed *** enterprise groups are facing the transformation and upgrading from domestic leadership to internationalization,achieving revenue growth of nearly 10 billion yuan per year against the *** severe and complex internal and external environment has brought many challenges to the supply chain for *** article focuses on the goal of an“enterprise supply chain system focusing on value creation,strengthening system linkage,and improving overall chain efficiency,”aiming to find solutions to problems such as strong demand variability,frequent emergency needs,coexistence of project shortages and inventory surplus,long material turnover cycles,and high organizational *** searching for key activities in the entire business chain of demand,design,production,service,and finance,implementing source planning,process control,system linkage,analysis and summary,and team collaboration,we have achieved more scientific demand forecasting,more accurate planning,more effective procurement cost reduction,more stable production performance supply,more convenient inventory sharing services,and more efficient integration of business and financial policies.

关键词： Supply chain management Full chain benefits Value creation Purchasing management

A Fault-Tolerant Mobility-Aware Caching Method in Edge Computing

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Computer Modeling in engineering & Sciences 2024年第7期140卷 907-927页

作者： Yong Ma Han Zhao Kunyin Guo Yunni Xia Xu Wang Xianhua Niu Dongge Zhu Yumin Dong School of Computer Information engineering Jiangxi Normal UniversityNanchang330000China School of Digital Industry Jiangxi Normal UniversityShangrao334000China The College of Computer Science Chongqing UniversityChongqing400044China College of Mechanical and Vehicle engineering Chongqing UniversityChongqing400030China School of Computer and Software engineering Xihua UniversityChengdu610039China Electric Power Research Institute of State Grid Ningxia Electric Power Company ltd. Yinchuan750002China College of Computer and Information Science Chongqing Normal UniversityChongqing401331China

Mobile Edge Computing(MEC)is a technology designed for the on-demand provisioning of computing and storage services,strategically positioned close to *** the MEC environment,frequently accessed content can be deployed and cached on edge servers to optimize the efficiency of content delivery,ultimately enhancing the quality of the user ***,due to the typical placement of edge devices and nodes at the network’s periphery,these components may face various potential fault tolerance challenges,including network instability,device failures,and resource *** the dynamic nature ofMEC,making high-quality content caching decisions for real-time mobile applications,especially those sensitive to latency,by effectively utilizing mobility information,continues to be a significant *** response to this challenge,this paper introduces FT-MAACC,a mobility-aware caching solution grounded in multi-agent deep reinforcement learning and equipped with fault tolerance *** approach comprehensively integrates content adaptivity algorithms to evaluate the priority of highly user-adaptive cached ***,it relies on collaborative caching strategies based onmulti-agent deep reinforcement learningmodels and establishes a fault-tolerancemodel to ensure the system’s reliability,availability,and *** results unequivocally demonstrate that FTMAACC outperforms its peer methods in cache hit rates and transmission latency.

关键词： Mobile edge networks mobility fault tolerance cooperative caching multi-agent deep reinforcement learning content prediction