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Connectedness of Cone-efficient Solution Set for Cone-quasiconvex Multiobjective Programming in Hausdorff Topological Vector Spaces 被引量:1
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作者 ZHOU Xuan-wei 《Chinese Quarterly Journal of Mathematics》 CSCD 2010年第1期132-139,共8页
This paper deals with the connectedness of the cone-efficient solution set for vector optimization in locally convex Hausdorff topological vector spaces. The connectedness of the cone-efficient solution set is proved ... This paper deals with the connectedness of the cone-efficient solution set for vector optimization in locally convex Hausdorff topological vector spaces. The connectedness of the cone-efficient solution set is proved for multiobjective programming defined by a continuous one-to-one cone-quasiconvex mapping on a compact convex set of alternatives. During the proof, the generalized saddle theorem plays a key role. 展开更多
关键词 multiobjective programming cone-efficient solution cone-quasiconvex mapping generalized saddle theorem connectedness
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A Two-Layer Multiobjective Optimal Energy Management Strategy Considering Fuel Cell/Battery Lifetime
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作者 Zhaoyang Shen Zhidong Qi +2 位作者 Jie Zhou Junsong Xu Liang Shan 《Carbon and Hydrogen》 2025年第1期80-96,共17页
To optimize the operating efficiency and extend the lifespan of the multistack fuel cell hybrid system(MFCHS),this paper proposes a two-layer multiobjective optimal energy management strategy that considers the degrad... To optimize the operating efficiency and extend the lifespan of the multistack fuel cell hybrid system(MFCHS),this paper proposes a two-layer multiobjective optimal energy management strategy that considers the degradation of the fuel cell and the battery.Regarding the issues that power fluctuations damage the fuel cells'lifespan and high-current charging and discharging lead to battery capacity decay,the first layer of the strategy adopts locally weighted scatterplot smoothing(LOWESS)to smooth the output power of the fuel cells and prevent the battery from operating under high-current conditions.The second layer considers the uneven degree of degradation among the fuel cells and employs the dandelion optimizer(DO)algorithm to solve the objective function with an aging adaptive factor,optimizing the efficiency and lifespan.Meanwhile,the DO algorithm is enhanced by tent chaotic mapping and differential variation to improve the convergence speed and accuracy.Compared with the equivalent hydrogen consumption minimization strategy(ECMS)and the equal distribution strategy,the proposed strategy improves the average operating efficiency of the fuel cells,effectively reduces the degradation of the fuel cells and the capacity degradation of the battery,and maintains the performance consistency among the fuel cells. 展开更多
关键词 dandelion optimizer multiobjective optimization multistack fuel cell hybrid system
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Variable Reconstruction for Evolutionary Expensive Large-Scale Multiobjective Optimization and Its Application on Aerodynamic Design
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作者 Jianqing Lin Cheng He +1 位作者 Ye Tian Linqiang Pan 《IEEE/CAA Journal of Automatica Sinica》 2025年第4期719-733,共15页
Expensive multiobjective optimization problems(EMOPs)are complex optimization problems exacted from realworld applications,where each objective function evaluation(FE)involves expensive computations or physical experi... Expensive multiobjective optimization problems(EMOPs)are complex optimization problems exacted from realworld applications,where each objective function evaluation(FE)involves expensive computations or physical experiments.Many surrogate-assisted evolutionary algorithms(SAEAs)have been designed to solve EMOPs.Nevertheless,EMOPs with large-scale decision variables remain challenging for existing SAEAs,leading to difficulties in maintaining convergence and diversity.To address this deficiency,we proposed a variable reconstructionbased SAEA(VREA)to balance convergence enhancement and diversity maintenance.Generally,a cluster-based variable reconstruction strategy reconstructs the original large-scale decision variables into low-dimensional weight variables.Thus,the population can be rapidly pushed towards the Pareto set(PS)by optimizing low-dimensional weight variables with the assistance of surrogate models.Population diversity is improved due to the cluster-based variable reconstruction strategy.An adaptive search step size strategy is proposed to balance exploration and exploitation further.Experimental comparisons with four state-of-the-art SAEAs are conducted on benchmark EMOPs with up to 1000 decision variables and an aerodynamic design task.Experimental results demonstrate that VREA obtains well-converged and diverse solutions with limited real FEs. 展开更多
关键词 Aerodynamic design large-scale optimization multiobjective evolutionary algorithm surrogate model variable reconstruction
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Automated inverse design of asymmetric excavation retaining structures using multiobjective optimization
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作者 Qiwei Wan Changjie Xu +2 位作者 Xiangyu Wang Haibin Ding Xiaozhen Fan 《Journal of Rock Mechanics and Geotechnical Engineering》 2025年第11期7351-7366,共16页
Conventional pit excavation engineering methods often struggle to manage the complex deformation patterns associated with asymmetric excavations,resulting in significant safety risks and increased project costs.These ... Conventional pit excavation engineering methods often struggle to manage the complex deformation patterns associated with asymmetric excavations,resulting in significant safety risks and increased project costs.These challenges highlight the need for more precise and efficient design methodologies to ensure structural stability and economic feasibility.This research proposes an innovative automatic optimization inverse design method(AOIDM)that integrates an enhanced genetic algorithm(EGA)with a multiobjective optimization model.By combining advanced computational techniques with engineering principles,this approach improves search efficiency by 30%and enhances deformation control accuracy by 25%.Additionally,the approach exhibits potential for reducing carbon emissions to align with sustainable engineering goals.The effectiveness of this approach was validated through comprehensive data analysis and practical case studies,demonstrating its ability to optimize retaining structure designs under complex asymmetric loading conditions.This research establishes a new standard for precision and efficiency in automated excavation design,with accompanying improvements in safety and cost-effectiveness.Furthermore,it lays the foundation for future geotechnical engineering advancements,offering a robust solution to one of the most challenging aspects of modern excavation projects. 展开更多
关键词 multiobjective optimization Enhanced genetic algorithm(EGA) Inverse design Deformation control Economic optimization
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Real-Time Dynamic Multiobjective Path Planning:A Case Study
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作者 Hongle Li SeongKi Kim 《Computers, Materials & Continua》 2025年第12期5571-5594,共24页
Path planning is a fundamental component in robotics and game artificial intelligence that considerably influences the motion efficiency of robots and unmanned aerial vehicles,as well as the realism and immersion of v... Path planning is a fundamental component in robotics and game artificial intelligence that considerably influences the motion efficiency of robots and unmanned aerial vehicles,as well as the realism and immersion of virtual environments.However,traditional algorithms are often limited to single-objective optimization and lack real-time adaptability to dynamic environments.This study addresses these limitations through a proposed realtime dynamic multiobjective(RDMO)path-planning algorithm based on an enhanced A^(*) framework.The proposed algorithm employs a queue-based structure and composite multiheuristic functions to dynamically manage game tasks and compute optimal paths under changing-map-connectivity conditions in real time.Simulation experiments are conducted using real-world road network data and benchmarked against mainstream hybrid approaches based on genetic algorithms(GAs)and simulated annealing(SA).The results show that the computational speed of the RDMO algorithm is 88 and 73 times faster than that of the GA-and SA-based solutions,respectively,while the total planned path length is reduced by 58%and 33%,respectively.In addition,the RDMO algorithm also shows excellent responsiveness to dynamic changes in map connectivity and can achieve real-time replanning with a minimal computational overhead.The research results prove that the RDMO algorithm provides a robust and efficient solution for multiobjective path planning in games and robotics applications and has a great application potential in improving system performance and user experience in related fields in the future. 展开更多
关键词 multiobjective optimization path planning real-time system dynamic environments A*algorithm game artificial intelligence
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Higher-order optimality conditions for multiobjective optimization through a new type of directional derivatives
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作者 HUANG Zheng-gang 《Applied Mathematics(A Journal of Chinese Universities)》 2025年第3期543-557,共15页
This paper deals with extensions of higher-order optimality conditions for scalar optimization to multiobjective optimization.A type of directional derivatives for a multiobjective function is proposed,and with this n... This paper deals with extensions of higher-order optimality conditions for scalar optimization to multiobjective optimization.A type of directional derivatives for a multiobjective function is proposed,and with this notion characterizations of strict local minima of order k for a multiobjective optimization problem with a nonempty set constraint are established,generalizing the corresponding scalar case obtained by Studniarski[3].Also necessary not sufficient and sufficient not necessary optimality conditions for this minima are derived based on our directional derivatives,which are generalizations of some existing scalar results and equivalent to some existing multiobjective ones.Many examples are given to illustrate them there. 展开更多
关键词 strict local minima of order k multiobjective optimization higher-order optimality conditions higher-order directional derivatives
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Knowledge Classification-Assisted Evolutionary Multitasking for Two-Task Multiobjective Optimization Problems
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作者 Xiaoling Wang Qi Kang +3 位作者 MengChu Zhou Qi Deng Zheng Fan Haoyue Liu 《IEEE/CAA Journal of Automatica Sinica》 2025年第6期1176-1193,共18页
To realize Industry 5.0,manufacturers face various optimization problems that seldom appear in isolation.Evolutionary MultiTasking(EMT)is an effective method to solve multiple related problems by extracting and utiliz... To realize Industry 5.0,manufacturers face various optimization problems that seldom appear in isolation.Evolutionary MultiTasking(EMT)is an effective method to solve multiple related problems by extracting and utilizing common knowledge.Knowledge transfer is the key to the effectiveness of EMT.Existing EMT methods mainly focus on designing effective intertask learning methods and ignore the fact that provided knowledge's appropriateness also has a significant effect on EMT's performance.There is plentiful knowledge in assistant tasks,and knowledge transfer may not work well and even lead to a negative effect if useless knowledge is selected to guide target tasks.EMT is thus confronted with a challenge to find appropriate knowledge.This work proposes an efficient knowledge classification-assisted EMT framework to identify and select valuable knowledge from assistant tasks.During the evolution process,better-performing candidates are supposed to have advantages in exploitation.Therefore,assistant individuals that are similar to better-performing target individuals are used to provide positive knowledge.Specifically,the target sub-population is divided into different levels and then a classifier is trained to divide assistant sub-population.Considering that target and assistant sub-populations have different characteristics,we use domain adaptation to reduce their distribution discrepancies.In this way,the trained classifier can classify assistant individuals more accurately,and truly useful knowledge can be selected for target tasks.The superior performance of our proposed framework over state-of-the-art algorithms is verified via a series of benchmark problems. 展开更多
关键词 Artificial intelligence evolutionary multitasking intelligent optimization inter-task learning knowledge classification knowledge transfer machine learning multiobjective optimization
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Programmable mixed-kernel based on MoTe_(2)/MoS_(2)heterojunction for support vector machine learning
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作者 Xinyu Huang Jiapeng Du +3 位作者 Langlang Xu Lei Tong Xiangxiang Yu Lei Ye 《Journal of Semiconductors》 2026年第3期110-116,共7页
The von Neumann bottleneck in conventional computing architectures presents a significant challenge for data-inten-sive artificial intelligence applications.A promising approach involves designing specialized hardware... The von Neumann bottleneck in conventional computing architectures presents a significant challenge for data-inten-sive artificial intelligence applications.A promising approach involves designing specialized hardware with on-chip parameter tunability,which directly accelerates machine learning functions.This work demonstrates a continuously tunable mixed-kernel function physically realized within a van der Waals heterostructure.We designed and fabricated a MoTe_(2)/MoS_(2)type-Ⅱvertical heterojunction phototransistor,which exhibits a non-monotonic,Gaussian-like optoelectronic response owing to its unique inter-layer charge transfer mechanism.This intrinsic physical behavior directly maps to a mixed-kernel function combining Gaussian and Sigmoid characteristics.Furthermore,the hardware kernel can be continuously modulated by in-situ tuning of external opti-cal stimuli.The mixed-kernel exhibited exceptional performance,achieving precision,accuracy,and area under the curve(AUC)values of 95.8%,96%,and 0.9986,respectively,significantly outperforming conventional kernels.By successfully embedding a complex,adaptable mathematical function into the intrinsic physical properties of a single device,this work pioneers a novel pathway toward next-generation,energy-efficient intelligent systems with hardware-level adaptability. 展开更多
关键词 programmable mixed-kernel HETEROJUNCTION support vector machine
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Support Vector-Guided Class-Incremental Learning:Discriminative Replay with Dual-Alignment Distillation
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作者 Moyi Zhang Yixin Wang Yu Cheng 《Computers, Materials & Continua》 2026年第3期2040-2061,共22页
Modern intelligent systems,such as autonomous vehicles and face recognition,must continuously adapt to new scenarios while preserving their ability to handle previously encountered situations.However,when neural netwo... Modern intelligent systems,such as autonomous vehicles and face recognition,must continuously adapt to new scenarios while preserving their ability to handle previously encountered situations.However,when neural networks learn new classes sequentially,they suffer from catastrophic forgetting—the tendency to lose knowledge of earlier classes.This challenge,which lies at the core of class-incremental learning,severely limits the deployment of continual learning systems in real-world applications with streaming data.Existing approaches,including rehearsalbased methods and knowledge distillation techniques,have attempted to address this issue but often struggle to effectively preserve decision boundaries and discriminative features under limited memory constraints.To overcome these limitations,we propose a support vector-guided framework for class-incremental learning.The framework integrates an enhanced feature extractor with a Support Vector Machine classifier,which generates boundary-critical support vectors to guide both replay and distillation.Building on this architecture,we design a joint feature retention strategy that combines boundary proximity with feature diversity,and a Support Vector Distillation Loss that enforces dual alignment in decision and semantic spaces.In addition,triple attention modules are incorporated into the feature extractor to enhance representation power.Extensive experiments on CIFAR-100 and Tiny-ImageNet demonstrate effective improvements.On CIFAR-100 and Tiny-ImageNet with 5 tasks,our method achieves 71.68%and 58.61%average accuracy,outperforming strong baselines by 3.34%and 2.05%.These advantages are consistently observed across different task splits,highlighting the robustness and generalization of the proposed approach.Beyond benchmark evaluations,the framework also shows potential in few-shot and resource-constrained applications such as edge computing and mobile robotics. 展开更多
关键词 Class-incremental learning catastrophic forgetting support vector machine knowledge distillation
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Personalized Differential Privacy for Support Vector Machines
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作者 WANG Xiaofeng LIU Xingwei XU Wangli 《Journal of Systems Science & Complexity》 2026年第1期180-202,共23页
The support vector machine,a widely used binary classification method,may expose sensitive information during training.To address this,the authors propose a personalized differential privacy method that extends differ... The support vector machine,a widely used binary classification method,may expose sensitive information during training.To address this,the authors propose a personalized differential privacy method that extends differential privacy.Specifically,the authors introduce personalized differentially private support vector machines to meet different individuals'privacy requirements,using a reweighting strategy and the Laplace mechanism.Theoretical analysis demonstrates that the proposed methods simultaneously satisfy the requirements of personalized differential privacy and ensure model prediction accuracy at these privacy levels.Extensive experiments demonstrate that the proposed methods outperform the existing methods. 展开更多
关键词 Laplace mechanism personalized differential privacy reweighting strategy support vector machine
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Adeno-associated viral vectors for modeling Parkinson's disease in non-human primates
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作者 Julia Chocarro José L.Lanciego 《Neural Regeneration Research》 2026年第1期224-232,共9页
The development of clinical candidates that modify the natural progression of sporadic Parkinson's disease and related synucleinopathies is a praiseworthy endeavor,but extremely challenging.Therapeutic candidates ... The development of clinical candidates that modify the natural progression of sporadic Parkinson's disease and related synucleinopathies is a praiseworthy endeavor,but extremely challenging.Therapeutic candidates that were successful in preclinical Parkinson's disease animal models have repeatedly failed when tested in clinical trials.While these failures have many possible explanations,it is perhaps time to recognize that the problem lies with the animal models rather than the putative candidate.In other words,the lack of adequate animal models of Parkinson's disease currently represents the main barrier to preclinical identification of potential disease-modifying therapies likely to succeed in clinical trials.However,this barrier may be overcome by the recent introduction of novel generations of viral vectors coding for different forms of alpha-synuclein species and related genes.Although still facing several limitations,these models have managed to mimic the known neuropathological hallmarks of Parkinson's disease with unprecedented accuracy,delineating a more optimistic scenario for the near future. 展开更多
关键词 adeno-associated viral vectors ALPHA-SYNUCLEIN DOPAMINE Lewy bodies NEURODEGENERATION NEUROMELANIN NEUROPATHOLOGY substantia nigra
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Yaw stabilization and maneuvering control of tailless flying wing by co-directional fluidic thrust vectoring
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作者 Liu ZHANG Meng HE 《Chinese Journal of Aeronautics》 2026年第1期66-77,共12页
Fluidic Thrust Vectoring(FTV)is used for the yaw attitude control of tailless flying wing,which can significantly improve stealth performance,maneuverability and lateral/heading maneuverability.The FTV control scheme ... Fluidic Thrust Vectoring(FTV)is used for the yaw attitude control of tailless flying wing,which can significantly improve stealth performance,maneuverability and lateral/heading maneuverability.The FTV control scheme of co-directional secondary flow was designed based on a 30 kgf thrust turbojet engine,an equivalent rudder deflection control variable of Mass Flow Combination(MFC)was proposed,and a control model was established to form a FTV control system scheme,which was integrated with the flight control system of a 100 kg tailless flying wing with medium aspect ratio to achieve closed-loop control of the yaw attitude based on FTV.The heading stability augmentation and maneuvering control characteristics and time response characteristics of tailless flying wing by FTV were quantitatively studied through virtual flight test in a wind tunnel at a wind speed of 35 m/s.The results show that the control strategy based on MFC achieves bidirectional continuous and stable control of thrust vector angle in a range of±11°,and the thrust vector angle varies monotonically with MFC;the co-directional FTV realizes bidirectional continuous and stable control of the yaw attitude of tailless flying wing,without longitudinal/lateral coupling moment.The increment of the maximum yawing moment coefficient is 0.0029,the maximum yaw rate is 7.55(°)/s,and the response time of the yaw rate of the vectoring nozzle actuated by the secondary flow is about 0.06 s,which satisfies the heading stability augmentation and maneuvering control response requirements of the aircraft with statically unstable heading,and provides new control means for the heading rudderless attitude control of tailless flying wing. 展开更多
关键词 Thrust vectoring Flow control Coanda effect Flying-wing aircraft Flight tests Yaw control
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Using mixed kernel support vector machine to improve the predictive accuracy of genome selection
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作者 Jinbu Wang Wencheng Zong +6 位作者 Liangyu Shi Mianyan Li Jia Li Deming Ren Fuping Zhao Lixian Wang Ligang Wang 《Journal of Integrative Agriculture》 2026年第2期775-787,共13页
The advantages of genome selection(GS) in animal and plant breeding are self-evident.Traditional parametric models have disadvantage in better fit the increasingly large sequencing data and capture complex effects acc... The advantages of genome selection(GS) in animal and plant breeding are self-evident.Traditional parametric models have disadvantage in better fit the increasingly large sequencing data and capture complex effects accurately.Machine learning models have demonstrated remarkable potential in addressing these challenges.In this study,we introduced the concept of mixed kernel functions to explore the performance of support vector machine regression(SVR) in GS.Six single kernel functions(SVR_L,SVR_C,SVR_G,SVR_P,SVR_S,SVR_L) and four mixed kernel functions(SVR_GS,SVR_GP,SVR_LS,SVR_LP) were used to predict genome breeding values.The prediction accuracy,mean squared error(MSE) and mean absolute error(MAE) were used as evaluation indicators to compare with two traditional parametric models(GBLUP,BayesB) and two popular machine learning models(RF,KcRR).The results indicate that in most cases,the performance of the mixed kernel function model significantly outperforms that of GBLUP,BayesB and single kernel function.For instance,for T1 in the pig dataset,the predictive accuracy of SVR_GS is improved by 10% compared to GBLUP,and by approximately 4.4 and 18.6% compared to SVR_G and SVR_S respectively.For E1 in the wheat dataset,SVR_GS achieves 13.3% higher prediction accuracy than GBLUP.Among single kernel functions,the Laplacian and Gaussian kernel functions yield similar results,with the Gaussian kernel function performing better.The mixed kernel function notably reduces the MSE and MAE when compared to all single kernel functions.Furthermore,regarding runtime,SVR_GS and SVR_GP mixed kernel functions run approximately three times faster than GBLUP in the pig dataset,with only a slight increase in runtime compared to the single kernel function model.In summary,the mixed kernel function model of SVR demonstrates speed and accuracy competitiveness,and the model such as SVR_GS has important application potential for GS. 展开更多
关键词 genome selection machine learning support vector machine kernel function mixed kernel function
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Asymmetric Voltage Vector-based Initial Rotor Position Detection in Four-switch Inverter Fed BLDC Motors
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作者 Xinmin Li Kun Liu +2 位作者 Lu Zhou Tingna Shi Wei Chen 《CES Transactions on Electrical Machines and Systems》 2026年第1期77-86,共10页
In position-sensorless brushless direct current(DC)motors(BLDCMs)fed by a four-switch three-phase(FSTP)inverter,only two phases are fully controlled,while the remaining phase is tied to the midpoint of the split DC-li... In position-sensorless brushless direct current(DC)motors(BLDCMs)fed by a four-switch three-phase(FSTP)inverter,only two phases are fully controlled,while the remaining phase is tied to the midpoint of the split DC-link capacitors.The voltage pulses required by inductance-based initial position detection can cause unequal discharge of the series capacitors,shifting the neutral-point voltage away from half of DC-link voltage(U_(dc)/2).This neutral-point drift breaks the spatial symmetry of the inverter voltage vectors,so the 360°electrical period can no longer be evenly partitioned into six sectors during initial rotor position detection.To address this issue,this paper proposes a detection-pulse injection sequence that explicitly accounts for the asymmetric voltage vectors of the FSTP inverter.With the proposed sequence,the initial rotor position can be identified within a 30°electrical sector.The method requires no additional voltage or current sensors,and experimental results confirm its feasibility. 展开更多
关键词 Brushless direct current(DC)motor(BLDCM) Four-switch three-phase(FSTP)inverter Asymmetric voltage vector Initial position detection
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A Convolutional Neural Network-Based Deep Support Vector Machine for Parkinson’s Disease Detection with Small-Scale and Imbalanced Datasets
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作者 Kwok Tai Chui Varsha Arya +2 位作者 Brij B.Gupta Miguel Torres-Ruiz Razaz Waheeb Attar 《Computers, Materials & Continua》 2026年第1期1410-1432,共23页
Parkinson’s disease(PD)is a debilitating neurological disorder affecting over 10 million people worldwide.PD classification models using voice signals as input are common in the literature.It is believed that using d... Parkinson’s disease(PD)is a debilitating neurological disorder affecting over 10 million people worldwide.PD classification models using voice signals as input are common in the literature.It is believed that using deep learning algorithms further enhances performance;nevertheless,it is challenging due to the nature of small-scale and imbalanced PD datasets.This paper proposed a convolutional neural network-based deep support vector machine(CNN-DSVM)to automate the feature extraction process using CNN and extend the conventional SVM to a DSVM for better classification performance in small-scale PD datasets.A customized kernel function reduces the impact of biased classification towards the majority class(healthy candidates in our consideration).An improved generative adversarial network(IGAN)was designed to generate additional training data to enhance the model’s performance.For performance evaluation,the proposed algorithm achieves a sensitivity of 97.6%and a specificity of 97.3%.The performance comparison is evaluated from five perspectives,including comparisons with different data generation algorithms,feature extraction techniques,kernel functions,and existing works.Results reveal the effectiveness of the IGAN algorithm,which improves the sensitivity and specificity by 4.05%–4.72%and 4.96%–5.86%,respectively;and the effectiveness of the CNN-DSVM algorithm,which improves the sensitivity by 1.24%–57.4%and specificity by 1.04%–163%and reduces biased detection towards the majority class.The ablation experiments confirm the effectiveness of individual components.Two future research directions have also been suggested. 展开更多
关键词 Convolutional neural network data generation deep support vector machine feature extraction generative artificial intelligence imbalanced dataset medical diagnosis Parkinson’s disease small-scale dataset
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GoVector:I/O-高效的高维向量近邻查询缓存策略
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作者 周依杰 林圣原 +4 位作者 巩树凤 余松 范书豪 张岩峰 于戈 《软件学报》 北大核心 2026年第3期1021-1036,共16页
基于图结构的高维向量索引(索引图)因其高效的近似最近邻搜索能力,已成为大规模向量检索的主流方法.索引图执行近似最近邻搜索(approximate nearest neighbor search,ANNS)的过程分为两个阶段:第1阶段从入口点出发快速定位到查询向量附... 基于图结构的高维向量索引(索引图)因其高效的近似最近邻搜索能力,已成为大规模向量检索的主流方法.索引图执行近似最近邻搜索(approximate nearest neighbor search,ANNS)的过程分为两个阶段:第1阶段从入口点出发快速定位到查询向量附近区域;第2阶段在查询向量附近搜索离其最近的k个向量.然而,由于索引图需存储大量邻接关系,导致内存开销大,因此实际部署时通常需将其存储于外存.当执行近似最近邻搜索时,按需加载索引图和向量数据会导致频繁发生I/O操作,并成为检索性能的主要瓶颈(I/O时间占90%以上).现有系统利用入口点及其附近邻居被高频访问的特性,采用静态缓存策略将入口点及其若干跳邻居预先缓存在内存中,以减少第1阶段的I/O访问.然而分析发现,第2阶段为了获取更高精度的检索结果,需访问大量与查询向量相关的图顶点,成为I/O开销的主要来源.由于第2阶段的访问顶点随查询向量动态变化,现有静态缓存策略难以有效命中,导致其在此阶段几乎失效.针对此问题,设计了一个静态-动态混合缓存策略GoVector,其核心设计体现在:(1)静态缓存区预加载入口点及其高频近邻;(2)动态缓存区自适应地缓存第2阶段中空间局部性高的顶点.为了进一步适配第2阶段中以向量相似性为导向的搜索过程,设计了基于向量空间相似性磁盘布局策略,通过重排顶点存储顺序,使相似向量在物理存储上聚集于相同或相邻磁盘页,从而显著提升数据访问的局部性.这种双重优化机制使得缓存命中率得到显著提升,有效降低了整体I/O开销.在多个公开数据集上的实验结果表明,当召回率为90%时,相较于当前最先进的基于磁盘的索引图系统,GoVector实现I/O次数平均降低46%、查询吞吐率提升1.73倍、延迟下降42%. 展开更多
关键词 高维向量 近似最近邻搜索 索引图
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New immune multiobjective optimization algorithm and its application in boiler combustion optimization 被引量:4
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作者 周霞 沈炯 +1 位作者 沈剑贤 李益国 《Journal of Southeast University(English Edition)》 EI CAS 2010年第4期563-568,共6页
In order to meet the requirements of combustion optimization for saving energy and reducing pollutant emission simultaneously,an immune cell subsets based multiobjective optimization algorithm(ICSMOA)is proposed.In ... In order to meet the requirements of combustion optimization for saving energy and reducing pollutant emission simultaneously,an immune cell subsets based multiobjective optimization algorithm(ICSMOA)is proposed.In the ICSMOA,the subset division operator and the immunological tolerance operation are defined.Preference can be easily addressed by using the subset division operator,and the distribution of the solutions can be guaranteed by the immunological tolerance operation.Using the ICSMOA,a group of Pareto optimal solutions can be obtained.However,by the traditional weighting method(WM),only one solution can be obtained and it cannot be judged as Pareto optimal or not.In contrast to the solutions obtained by the repeatedly performed WM,the simulation results show that most solutions obtained by the ICSMOA are better than the solutions obtained by the WM.In addition,the Pareto front obtained by the ICSMOA is not as uniform as most classical multiobjective optimization algorithms.More optimal solutions which meet the preference set by the decision-maker can be obtained and they are very useful for industrial application. 展开更多
关键词 combustion optimization multiobjective optimizat-ion immune cell subsets
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Multiobjective particle swarm inversion algorithm for two-dimensional magnetic data 被引量:8
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作者 熊杰 张涛 《Applied Geophysics》 SCIE CSCD 2015年第2期127-136,273,共11页
Regularization inversion uses constraints and a regularization factor to solve ill- posed inversion problems in geophysics. The choice of the regularization factor and of the initial model is critical in regularizatio... Regularization inversion uses constraints and a regularization factor to solve ill- posed inversion problems in geophysics. The choice of the regularization factor and of the initial model is critical in regularization inversion. To deal with these problems, we propose a multiobjective particle swarm inversion (MOPSOI) algorithm to simultaneously minimize the data misfit and model constraints, and obtain a multiobjective inversion solution set without the gradient information of the objective function and the regularization factor. We then choose the optimum solution from the solution set based on the trade-off between data misfit and constraints that substitute for the regularization factor. The inversion of synthetic two-dimensional magnetic data suggests that the MOPSOI algorithm can obtain as many feasible solutions as possible; thus, deeper insights of the inversion process can be gained and more reasonable solutions can be obtained by balancing the data misfit and constraints. The proposed MOPSOI algorithm can deal with the problems of choosing the right regularization factor and the initial model. 展开更多
关键词 multiobjective inversion particle swarm optimization regularization factor global search magnetic data
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MULTIOBJECTIVE OPTIMIZATION OF EIGHT-DOF VEHICLE SUSPENSION BASED ON GAME THEORY
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作者 宋崇智 赵又群 +1 位作者 谢能刚 王璐 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2010年第2期138-147,共10页
A systematic and effective optimization is proposed for the design of a three-dimensional (3-D) vehicle suspension model with eight degrees of freedom (DOF), including vertical seat motion, vehicle suspension, pit... A systematic and effective optimization is proposed for the design of a three-dimensional (3-D) vehicle suspension model with eight degrees of freedom (DOF), including vertical seat motion, vehicle suspension, pitching and rolling motions, and vertical wheel motions using the evolutionary game theory. A new design of the passive suspension is aided by game theory to attain the best compromise between ride quality and suspension deflections. Extensive simulations are performed on three type road surface models A, B, C pavement grades based on the guidelines provided by ISO-2631 with the Matlab/Simulink environment. The preliminary results show that, when the passive suspension is optimized via the proposed approach, a substantial improvement in the vertical ride quality is obtained while keeping the suspension deflections within their allowable clearance when the vehicle moves at a constant velocity v=20 m/s, and the comfort performance of a suspension seat can be enhanced by 20%-30%. 展开更多
关键词 vehicle suspensions multiobjective optimization game theory riding comfort
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Preference-based multiobjective artificial bee colony algorithm for optimization of superheated steam temperature control
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作者 周霞 沈炯 李益国 《Journal of Southeast University(English Edition)》 EI CAS 2014年第4期449-455,共7页
In order to incorporate the decision maker's preference into multiobjective optimization a preference-based multiobjective artificial bee colony algorithm PMABCA is proposed.In the proposed algorithm a novel referenc... In order to incorporate the decision maker's preference into multiobjective optimization a preference-based multiobjective artificial bee colony algorithm PMABCA is proposed.In the proposed algorithm a novel reference point based preference expression method is addressed.The fitness assignment function is defined based on the nondominated rank and the newly defined preference distance.An archive set is introduced for saving the nondominated solutions and an improved crowding-distance operator is addressed to remove the extra solutions in the archive.The experimental results of two benchmark test functions show that a preferred set of solutions and some other non-preference solutions are achieved simultaneously.The simulation results of the proportional-integral-derivative PID parameter optimization for superheated steam temperature verify that the PMABCA is efficient in aiding to making a reasonable decision. 展开更多
关键词 PREFERENCE multiobjective artificial bee colony superheated steam temperature control OPTIMIZATION
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