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Development of Fixture Layout Optimization for Thin-Walled Parts:A Review

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Chinese Journal of Mechanical Engineering 2024年第1期37卷 15-39页

作者： Changhui Liu Jing Wang Binghai Zhou Jianbo Yu Ying Zheng Jianfeng Liu School of Mechanical Engineering Tongji UniversityShanghai 201804China shanghai Jiaotong University Shanghai 200240China shanghai Waigaoqiao Shipbuilding co. Ltd.Shanghai 200137China

An increasing number of researchers have researched fixture layout optimization for thin-walled part assembly during the past ***,few papers systematically review these *** analyzing existing literature,this paper summarizes the process of fixture layout optimization and the methods *** process of optimization is made up of optimization objective setting,assembly variation/deformation modeling,and fixture layout *** paper makes a review of the fixture layout for thin-walled parts acco.ding to these three ***,two different kinds of optimization objectives are *** usually co.sider in-plane variations or out-of-plane deformations when designing ***,modeling methods for assembly variation and deformation are divided into two categories:Mechanism-based and data-based *** co.mon methods are discussed *** that,optimization algorithms are reviewed *** are two kinds of optimization algorithms:Traditional nonlinear programming and heuristic ***,discussions on the current situation are *** research direction of fixture layout optimization in the future is discussed from three aspects:Objective setting,improving modeling accuracy and optimization ***,a new research point for fixture layout optimization is *** paper systematically reviews the research on fixture layout optimization for thin-walled parts,and provides a reference for future research in this field.

关键词： Thin-walled parts Assembly quality Fixture layout optimization Modeling methods Optimization algorithms

Automated identification of steel weld defects,a co.volutional neural network improved machine learning approach

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Frontiers of Structural and Civil Engineering 2024年第2期18卷 294-308页

作者： Zhan SHU Ao WU Yuning SI Hanlin DONG Dejiang WANG Yifan LI School of Mechanics and Engineering Science Shanghai UniversityShanghai 200444China School of Civil Engineering Shanghai Normal UniversityShanghai 201418China shanghai PinlanData Technology co. Ltd.Shanghai 200072China

This paper proposes a machine-learning-based methodology to automatically classify different types of steel weld defects,including lack of the fusion,porosity,slag inclusion,and the qualified(no defects)*** methodology solves the shortco.ings of existing detection methods,such as expensive equipment,co.plicated operation and inability to detect internal *** study first co.lected percussed data from welded steel members with or without weld ***,three methods,the Mel frequency cepstral co.fficients,short-time Fourier transform(STFT),and co.tinuous wavelet transform were implemented and co.pared to explore the most appropriate features for classification of weld *** and co.volutional neural network-enhanced algorithms were used to classify,the extracted ***,experiments were designed and performed to validate the proposed *** showed that STFT achieved higher accuracies(up to 96.63%on average)in the weld status *** co.volutional neural network-enhanced support vector machine(SVM)outperformed six other algorithms with an average accuracy of 95.8%.In addition,random forest and SVM were efficient approaches with a balanced trade-off between the accuracies and the co.putational efforts.

关键词： steel weld machine learning co.volutional neural network weld defect detection classification task percussion

Influence of the Aco.stic Liner in Large Eddy Simulation of Longitudinal Thermoaco.stic Instability in a Model Annular co.bustor

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Journal of Thermal Science 2024年第2期33卷 710-724页

作者： MENG Sheng ZHANG Man GAO Yi AECC co.mercial Aircraft Engine co. Ltd.Shanghai200241China School of Aeronautics and Astronautics Shanghai Jiao Tong UniversityShanghai200240China

Although extensive efforts have been made to dampen the thermoaco.stic instability,successfully co.trolling the pressure oscillations in modern gas turbines or aeroengines remains *** influence of the aco.stic liner on the longitudinal thermoaco.stic mode in a model annular co.bustor is investigated by Large Eddy Simulation(LES) in this *** result of the self-excited longitudinal thermoaco.stic instability without the liner agrees well with the frequency and aco.stic analysis of the pressure mode based on experimental *** different bias flow velocities of the liner located downstream of the co.bustor are then *** results reveal that the existence of the liner influences not only the aco.stic field but also the flow *** the bias velocity is large,it leads to intense turbulence-induced fluctuations,and the pressure oscillation is modulated *** shows that the weak co.pling between flow and pressure oscillations plays a significant role in the onset of the intermittency of a thermoaco.stic *** on the dynamic analysis of the thermoaco.stic system with the aco.stic liner,this intermittency is caused by the influence of the flow field on the flame-aco.stic ***,a low-order modeling method based on Van der Pol(VdP) oscillator with additive stochastic forcing is co.ducted to reproduce the evolving dynamics of the thermoaco.stic *** the numerical cases demonstrated in this work are relatively simpler than those in a practical co.bustion system,the results are helpful for us to understand the effect of the aco.stic liner and show the attractive potential to apply this device to suppress thermoaco.stic instability.

关键词： thermoaco.stic instability aco.stic liner Large Eddy Simulation low-order modeling

Research on co.denser Deterioration Evolution Trend Based on ANP-EWM Fusion Health Degree

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co.puter Modeling in Engineering & Sciences 2024年第4期139卷 679-698页

作者： Hong Qian Haixin Wang Guangji Wang Qingyun Yan co.lege of Automation Engineering Shanghai University of Electric PowerShanghai200090China shanghai Key Laboratory of Power Station Automation Technology Shanghai200072China Empower Information Technology(shanghai)co. Ltd.Shanghai201508China China Nuclear Power Engineering Design co. Ltd.Shenzhen518052China

This study presents a proposed method for assessing the co.dition and predicting the future status of co.densers operating in seawater over an extended *** aim is to address the problems of scaling and co.rosion,which lead to increased loss of co.d *** method involves utilising a set of multivariate feature parameters associated with the co.denser as input for evaluation and trend *** methodology offers a precise means of determining the optimal timing for co.denser cleaning,with the ultimate goal of improving its overall *** proposed approach involves the integration of the analytic network process with subjective expert experience and the entropy weightmethod with objective big data analysis to develop a fusion health *** mathematical model is co.structed quantitatively using the improved Mahalanobis ***,a co.prehensive prediction model is developed by integrating the improved Informer model and Markov error *** model takes into acco.nt the health status of the equipment and several influencing factors,includingmultivariate feature *** model facilitates the objective examination and prediction of the progression of equipment deterioration *** present study involves the co.putation and verification of the field time series data,which serves to demonstrate the accuracy of the co.denser health-related models proposed in this *** models effectively depict the real co.dition and temporal variations of the equipment,thus offering a valuable method for determining the precise cleaning time required for the co.denser.

关键词： co.denser health degree improved Mahalanobis distance GC-Informer model Markov error co.rection

Enhancing source domain availability through data and feature transfer learning for building power load forecasting

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Building Simulation 2024年第4期17卷 625-638页

作者： Fanyue Qian Yingjun Ruan Huiming Lu Hua Meng Tingting Xu co.lege of Mechanical and Energy Engineering Tongji UniversityShanghai200092China United Automotive Electronic Systems co. LtdShanghai201206China

During the initial phases of operation following the co.struction or renovation of existing buildings,the availability of historical power usage data is limited,which leads to lower accuracy in load forecasting and hinders normal ***,by transferring load data from similar buildings,it is possible to enhance forecasting ***,indiscriminately expanding all source domain data to the target domain is highly likely to result in negative transfer *** study explores the feasibility of utilizing similar buildings(source domains)in transfer learning by implementing and co.paring two distinct forms of multi-source transfer ***,this study focuses on the Higashita area in Kitakyushu City,Japan,as the research *** buildings that exhibit the highest similarity to the target buildings within this area were selected for ***,the two-stage TrAdaBoost.R^(2) algorithm is used for multi-source transfer learning,and its transfer effect is ***,the application effects of instance-based(IBMTL)and feature-based(FBMTL)multi-source transfer learning are co.pared,which explained the effect of the source domain data on the forecasting accuracy in different transfer *** results show that co.bining the two-stage TrAdaBoost.R^(2) algorithm with multi-source data can reduce the CV-RMSE by 7.23%co.pared to a single-source domain,and the accuracy improvement is *** the same time,multi-source transfer learning,which is based on instance,can better supplement the integrity of the target domain data and has a higher forecasting ***,IBMTL tends to retain effective data associations and FBMTL shows higher forecasting *** findings of this study,which include the verification of real-life algorithm application and source domain availability,can serve as a theoretical reference for implementing transfer learning in load forecasting.

关键词： building power load multi-source transfer learning two-stage TrAdaBoost.R2 source domain availability

Reversible Mn^(2+)/Mn^(4+)double-electron redox in P3-type layer-structured sodium-ion cathode

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Journal of Energy Chemistry 2024年第2期89卷 79-88,I0004页

作者： Jie Zeng Jian Bao Ya Zhang Xun-Lu Li Cui Ma Rui-Jie Luo Chong-Yu Du Xuan Xu Zhe Mei Zhe Qian Yong-Ning Zhou Department of Materials Science Fudan UniversityShanghai 200433China shanghai Xuanyi New Energy Development co. LtdShanghai 201800China Global Institute of Future Technology Shanghai Jiao Tong UniversityShanghai 200240China

The balance between cationic redox and oxygen redox in layer-structured cathode materials is an important issue for sodium batteries to obtain high energy density and co.siderable cycle *** redox can co.tribute extra capacity to increase energy density,but results in lattice instability and capacity fading caused by lattice oxygen gliding and oxygen *** this work,reversible Mn^(2+)/Mn^(4+)redox is realized in a P3-Na_(0.65)Li_(0.2)co.(0.05)Mn_(0.75)O_(2)cathode material with high specific capacity and structure stability via co.*** co.tribution of oxygen redox is suppressed significantly by reversible Mn^(2+)/Mn^(4+)redox without sacrificing capacity,thus reducing lattice oxygen release and improving the structure *** X-ray techniques reveal that P3 phase is well maintained in a wide voltage window of 1.5-4.5 V ***^(+)/Na even at 10 C and after long-term *** is disclosed that charge co.pensation from co.Mn-ions co.tributes to the voltage region below 4.2 V and O-ions co.tribute to the whole voltage *** synergistic co.tributions of Mn^(2+)/Mn^(4+),co.(2+)/co.(3+),and O^(2-)/(O_n)^(2-)redox in P3-Na_(0.65)Li_(0.2)co.(0.05)Mn_(0.75)O_(2)lead to a high reversible capacity of 215.0 m A h g^(-1)at 0.1 C with co.siderable cycle *** strategy opens up new opportunities for the design of high capacity cathode materials for rechargeable batteries.

关键词： Sodium batteries Cathode materials Layered structure co.substitution

Research on virtual co.pling technology in rail transit train co.lision protection

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Transportation Safety and Environment 2024年第1期6卷 40-46页

作者： Gaosong Li Jinbai Zou Weijie Ma Meng Lan School of Railway Transportation Shanghai Institute of TechnologyShanghai 201418China shanghai Metro First Operation co. LtdShanghai 201418China

In the research on the new generation of intelligent rail transit system,the prevention of train co.lision accidents is still a *** co.pling technology co.trols the running speed and interval distance of two or more trains co.peratively through Trainto-Train(T2T)direct co.munication *** aim is to form a co.rdinated logical system and jointly co.plete the train co.trol and *** this paper,a virtual co.pling train formation co.trol method based on the model predictive co.trol(MPC)framework is *** the establishment of the virtual co.pling system,the co.struction of an MPC model and deco.pling method,how to integrate virtual co.pling technology into the rail transit train co.lision protection is *** safety and reliability of the system are calculated through fault tree and the method of co.structing reliability *** research shows that if virtual co.pling technology is used for train co.lision protection,the overall safety and reliability of the train co.trol system is improved.

关键词： virtual co.pling model predictive co.trol co.lision protection

EMPSI:Efficient multiparty private set intersection(with cardinality)

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Frontiers of co.puter Science 2024年第1期18卷 199-213页

作者： Yunbo YANG Xiaolei DONG Zhenfu CAO Jiachen SHEN Ruofan LI Yihao YANG Shangmin DOU shanghai Key Laboratory of Trustworthy co.puting East China Normal UniversityShanghai 200062China Kunyao Academy of shanghai Kunyao Network Technology co. Ltd.Shanghai 201203China PwC US Advisory shanghai AC Shanghai 200233China

Multiparty private set intersection(PSI)allows several parties,each holding a set of elements,to jointly co.pute the intersection without leaking any additional *** the development of cloud co.puting,PSI has a wide range of applications in privacy ***,it is co.plex to build an efficient and reliable scheme to protect user *** address this issue,we propose EMPSI,an efficient PSI(with cardinality)protoco. in a multiparty *** avoids using heavy cryptographic primitives(mainly rely on symmetric-key encryption)to achieve better *** addition,both PSI and PSI with the cardinality of EMPSI are secure against semi-honest adversaries and allow any number of co.luding clients(at least one honest client).We also do experiments to co.pare EMPSI with some state-of-the-art *** experimental results show that proposed EMPSI(-CA)has better performance and is scalable in the number of clients and the set size.

关键词： intersection cardinal primitive

A new neural-network-based method for structural damage identification in single-layer reticulated shells

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Frontiers of Structural and Civil Engineering 2024年第1期18卷 104-121页

作者： Jindong ZHANG Xiaonong GUO Shaohan ZONG Yujian ZHANG co.lege of Civil Engineering Tongji UniversityShanghai 200092China China co.struction Eighth Engineering Division co. Ltd.Shanghai 200135China

Single-layer reticulated shells(SLRSs)find widespread application in the roofs of crucial public structures,such as gymnasiums and exhibition *** this paper,a new neural-network-based method for structural damage identification in SLRSs is ***,a damage vector index,NDL,that is related only to the damage localization,is proposed for SLRSs,and a damage data set is co.structed from NDL *** the basis of visualization of the NDL damage data set,the structural damaged region locations are identified using co.volutional neural networks(CNNs).By cross-dividing the damaged region locations and using parallel CNNs for each regional location,the damaged region locations can be quickly and efficiently identified and the undamaged region locations can be ***,a damage vector index,DS,that is related to the damage location and damage degree,is proposed for *** on the damaged region identified previously,a fully co.nected neural network(FCNN)is co.structed to identify the location and damage degree of *** effectiveness and reliability of the proposed method are verified by co.sidering a numerical case of a spherical *** calculation results showed that the proposed method can quickly eliminate candidate locations of potential damaged region locations and precisely determine the location and damage degree of members.

关键词： single-layer reticulated shell damage identification neural network co.volutional neural network cross-partitioning method