期刊文献+
共找到3,680篇文章
< 1 2 184 >
每页显示 20 50 100
Link-16 anti-jamming performance evaluation based on grey relational analysis and cloud model
1
作者 NING Xiaoyan WANG Ying +1 位作者 WANG Zhenduo SUN Zhiguo 《Journal of Systems Engineering and Electronics》 2025年第1期62-72,共11页
Anti-jamming performance evaluation has recently received significant attention. For Link-16, the anti-jamming performance evaluation and selection of the optimal anti-jamming technologies are urgent problems to be so... Anti-jamming performance evaluation has recently received significant attention. For Link-16, the anti-jamming performance evaluation and selection of the optimal anti-jamming technologies are urgent problems to be solved. A comprehensive evaluation method is proposed, which combines grey relational analysis (GRA) and cloud model, to evaluate the anti-jamming performances of Link-16. Firstly, on the basis of establishing the anti-jamming performance evaluation indicator system of Link-16, the linear combination of analytic hierarchy process(AHP) and entropy weight method (EWM) are used to calculate the combined weight. Secondly, the qualitative and quantitative concept transformation model, i.e., the cloud model, is introduced to evaluate the anti-jamming abilities of Link-16 under each jamming scheme. In addition, GRA calculates the correlation degree between evaluation indicators and the anti-jamming performance of Link-16, and assesses the best anti-jamming technology. Finally, simulation results prove that the proposed evaluation model can achieve the objective of feasible and practical evaluation, which opens up a novel way for the research of anti-jamming performance evaluations of Link-16. 展开更多
关键词 LINK-16 ANTI-JAMMING grey relational analysis(GRA) cloud model combination weights
在线阅读 下载PDF
Control model for burning-bubble clouds formed by confined meltcast explosives under thermal stimulation
2
作者 Zhi Li Zhuoping Duan +4 位作者 Zhiling Bai Jixuan Jiao Liji Xu Liansheng Zhang Fenglei Huang 《Defence Technology(防务技术)》 2025年第6期268-283,共16页
DNAN-based insensitive melt-cast explosives have been widely utilized in insensitive munition in recent years. When constrained DNAN-based melt-cast explosives are ignited under thermal stimulation, the base explosive... DNAN-based insensitive melt-cast explosives have been widely utilized in insensitive munition in recent years. When constrained DNAN-based melt-cast explosives are ignited under thermal stimulation, the base explosive exists in a molten liquid state, where high-temperature gases expand and react in the form of bubble clouds within the liquid explosive;this process is distinctly different from the dynamic crack propagation process observed in the case of solid explosives. In this study, a control model for the reaction evolution of burning-bubble clouds was established to describe the reaction process and quantify the reaction violence of DNAN-based melt-cast explosives, considering the size distribution and activation mechanism of the burning-bubble clouds. The feasibility of the model was verified through experimental results. The results revealed that under geometrically similar conditions, with identical confinement strength and aspect ratio, larger charge structures led to extended initial gas flow and surface burning processes, resulting in greater reaction equivalence and violence at the casing fracture.Under constant charge volume and size, a stronger casing confinement accelerated self-enhanced burning, increasing the internal pressure, reaction degree, and reaction violence. Under a constant casing thickness and radius, higher aspect ratios led to a greater reaction violence at the casing fracture.Moreover, under a constant charge volume and casing thickness, higher aspect ratios resulted in a higher internal pressure, increased reaction degree, and greater reaction violence at the casing fracture. Further,larger ullage volumes extended the reaction evolution time and increased the reaction violence under constant casing dimensions. Through a matching design of the opening threshold of the pressure relief holes and the relief structure area, a stable burning reaction could be maintained until completion,thereby achieving a control of the reaction violence. The proposed model could effectively reflect the effects of the intrinsic burning rate, casing confinement strength, charge size, ullage volume, and pressure relief structure on the reaction evolution process and reaction violence, providing a theoretical method for the thermal safety design and reaction violence evaluation of melt-cast explosives. 展开更多
关键词 Melt-cast explosives Non-shock-initiated reaction Self-sustaining enhanced combustion Burning-bubble cloud model Pressure relief area Reaction violence
在线阅读 下载PDF
A cloud model target damage effectiveness assessment algorithm based on spatio-temporal sequence finite multilayer fragments dispersion
3
作者 Hanshan Li Xiaoqian Zhang Junchai Gao 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第10期48-64,共17页
To solve the problem of target damage assessment when fragments attack target under uncertain projectile and target intersection in an air defense intercept,this paper proposes a method for calculating target damage p... To solve the problem of target damage assessment when fragments attack target under uncertain projectile and target intersection in an air defense intercept,this paper proposes a method for calculating target damage probability leveraging spatio-temporal finite multilayer fragments distribution and the target damage assessment algorithm based on cloud model theory.Drawing on the spatial dispersion characteristics of fragments of projectile proximity explosion,we divide into a finite number of fragments distribution planes based on the time series in space,set up a fragment layer dispersion model grounded in the time series and intersection criterion for determining the effective penetration of each layer of fragments into the target.Building on the precondition that the multilayer fragments of the time series effectively assail the target,we also establish the damage criterion of the perforation and penetration damage and deduce the damage probability calculation model.Taking the damage probability of the fragment layer in the spatio-temporal sequence to the target as the input state variable,we introduce cloud model theory to research the target damage assessment method.Combining the equivalent simulation experiment,the scientific and rational nature of the proposed method were validated through quantitative calculations and comparative analysis. 展开更多
关键词 Target damage cloud model Fragments dispersion Effectiveness assessment Spatio-temporal sequence
在线阅读 下载PDF
Research on BIM Model Reshaping Method Based on 3D Point Cloud Recognition
4
作者 SHI Jin-yu YU Xian-feng +1 位作者 SI Zhan-jun ZHANG Ying-xue 《印刷与数字媒体技术研究》 CAS 北大核心 2024年第4期125-135,共11页
In view of the limitations of traditional measurement methods in the field of building information,such as complex operation,low timeliness and poor accuracy,a new way of combining three-dimensional scanning technolog... In view of the limitations of traditional measurement methods in the field of building information,such as complex operation,low timeliness and poor accuracy,a new way of combining three-dimensional scanning technology and BIM(Building Information Modeling)model was discussed.Focused on the efficient acquisition of building geometric information using the fast-developing 3D point cloud technology,an improved deep learning-based 3D point cloud recognition method was proposed.The method optimised the network structure based on RandLA-Net to adapt to the large-scale point cloud processing requirements,while the semantic and instance features of the point cloud were integrated to significantly improve the recognition accuracy and provide a precise basis for BIM model remodeling.In addition,a visual BIM model generation system was developed,which systematically transformed the point cloud recognition results into BIM component parameters,automatically constructed BIM models,and promoted the open sharing and secondary development of models.The research results not only effectively promote the automation process of converting 3D point cloud data to refined BIM models,but also provide important technical support for promoting building informatisation and accelerating the construction of smart cities,showing a wide range of application potential and practical value. 展开更多
关键词 3D point cloud RandLA-Net network BIM model OSG engine
在线阅读 下载PDF
中国与东盟国家水产品贸易影响因素研究——基于CMS模型的实证分析 被引量:2
5
作者 赵亮 袁倩 《价格月刊》 北大核心 2025年第2期68-75,共8页
基于2012—2022年中国与东盟国家7大类水产品贸易数据,并将水产品划分为鱼类水产品与非鱼类水产品,运用恒定市场份额(CMS)模型对中国与东盟国家水产品贸易影响因素进行实证分析。结果显示:市场规模效应对中国水产品向东盟国家出口具有... 基于2012—2022年中国与东盟国家7大类水产品贸易数据,并将水产品划分为鱼类水产品与非鱼类水产品,运用恒定市场份额(CMS)模型对中国与东盟国家水产品贸易影响因素进行实证分析。结果显示:市场规模效应对中国水产品向东盟国家出口具有积极的促进作用,而中国水产品出口与东盟国家水产品市场需求结构不相匹配且互补性较低;中国与东盟国家在水产品出口方面的竞争态势发生了显著变化,特别是在鱼类水产品出口领域中国的竞争力逐渐降低,水产品出口结构比较单一且竞争力不足。应提高中国与东盟水产品出口市场匹配度,减少产品结构风险和各类别水产品出口风险,同时进一步扩大中国对东盟水产品出口规模,促进中国水产品出口提质增效。 展开更多
关键词 中国与东盟国家 水产品贸易 cmS模型
在线阅读 下载PDF
中国茶叶出口摩洛哥驱动因素分析——基于CMS模型
6
作者 康学芹 张文华 +1 位作者 高焓诺 龚恕 《中国茶叶》 2025年第6期44-51,共8页
摩洛哥是“一带一路”沿线重要的茶叶市场,长期位居中国茶叶出口市场第1位,但近年中国茶叶对摩洛哥市场出口量波动较大。在对2010—2023年中国茶叶对摩洛哥出口额、市场占有率波动统计分析基础上,基于修正的CMS模型对2010—2022年分阶... 摩洛哥是“一带一路”沿线重要的茶叶市场,长期位居中国茶叶出口市场第1位,但近年中国茶叶对摩洛哥市场出口量波动较大。在对2010—2023年中国茶叶对摩洛哥出口额、市场占有率波动统计分析基础上,基于修正的CMS模型对2010—2022年分阶段实证分析了中国茶叶出口摩洛哥的波动驱动因素,揭示了出口结构滞后、竞争力衰减与市场需求脱节的核心矛盾。由此提出中国茶叶需要进一步创新,通过挖掘本地市场需求,以及开发新产品、改进原有产品性能、扩大使用量等措施以巩固提升市场地位。 展开更多
关键词 茶叶出口 驱动因素 摩洛哥 cmS模型
在线阅读 下载PDF
Risk transmission evaluation for parallel construction of warships based on IFCM and the cloud model
7
作者 GONG Jun HU Tao YAO Lu 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2022年第6期1224-1237,共14页
To cope with multi-directional transmission coupling,spreading, amplification, and chain reaction of risks during multiproject parallel construction of warships, a risk transmission evaluation method is proposed, whic... To cope with multi-directional transmission coupling,spreading, amplification, and chain reaction of risks during multiproject parallel construction of warships, a risk transmission evaluation method is proposed, which integrates an intuitionistic cloud model with a fuzzy cognitive map. By virtue of expectancy Ex, entropy En, and hyper entropy He, the risk fuzziness and randomness of the knowledge of experts are organically combined to develop a method for converting bi-linguistic variable decision-making information into the quantitative information of the intuitionistic normal cloud(INC) model. Subsequently, the threshold function and weighted summation operation in the traditional fuzzy cognitive map is converted into the INC ordered weighted averaging operator to create the risk transmission model based on the intuitionistic fuzzy cognitive map(IFCM) and the algorithm for solving it. Subsequently, the risk influence sequencing method based on INC and the risk rating method based on nearness are proposed on the basis of Monte Carlo simulation in order to realize the mutual conversion of the qualitative and quantitative information in the risk evaluation results.Example analysis is presented to verify the effectiveness and practicality of the methods. 展开更多
关键词 risk evaluation multi-project parallel intuitionistic fuzzy cognitive map(IFcm) intuitionistic normal cloud(INC)model warship construction.
在线阅读 下载PDF
Flatness predictive model based on T-S cloud reasoning network implemented by DSP 被引量:4
8
作者 ZHANG Xiu-ling GAO Wu-yang +1 位作者 LAI Yong-jin CHENG Yan-tao 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第10期2222-2230,共9页
The accuracy of present flatness predictive method is limited and it just belongs to software simulation. In order to improve it, a novel flatness predictive model via T-S cloud reasoning network implemented by digita... The accuracy of present flatness predictive method is limited and it just belongs to software simulation. In order to improve it, a novel flatness predictive model via T-S cloud reasoning network implemented by digital signal processor(DSP) is proposed. First, the combination of genetic algorithm(GA) and simulated annealing algorithm(SAA) is put forward, called GA-SA algorithm, which can make full use of the global search ability of GA and local search ability of SA. Later, based on T-S cloud reasoning neural network, flatness predictive model is designed in DSP. And it is applied to 900 HC reversible cold rolling mill. Experimental results demonstrate that the flatness predictive model via T-S cloud reasoning network can run on the hardware DSP TMS320 F2812 with high accuracy and robustness by using GA-SA algorithm to optimize the model parameter. 展开更多
关键词 T-S cloud reasoning neural NETWORK cloud model FLATNESS predictive model hardware implementation digital signal PROCESSOR genetic ALGORITHM and simulated annealing ALGORITHM (GA-SA)
在线阅读 下载PDF
Cloud model-clustering analysis based evaluation for ventilation system of underground metal mine in alpine region 被引量:6
9
作者 YAN Fang LI Zi-jun +4 位作者 DONG Long-jun HUANG Rui CAO Ri-hong GE Ji XU Kai-li 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第3期796-815,共20页
Ventilation system is significant in underground metal mine of alpine region.Reasonable evaluation of ventilation effectiveness will lead to a practical improvement for the maintenance and management of ventilation sy... Ventilation system is significant in underground metal mine of alpine region.Reasonable evaluation of ventilation effectiveness will lead to a practical improvement for the maintenance and management of ventilation system.However,it is difficult to make an effective evaluation of ventilation system due to the lack of classification criteria with respect to underground metal mine in alpine region.This paper proposes a novel evaluation method called the cloud model-clustering analysis(CMCA).Cloud model(CM)is utilized to process collected data of ventilation system,and they are converted into cloud descriptors by CM.Cloud similarity(CS)based Euclidean distance(ED)is proposed to make clustering analysis of assessed samples.Then the classification of assessed samples will be identified by clustering analysis results.A case study is developed based on CMCA.Evaluation results show that ventilation effectiveness can be well classified.Moreover,CM is used alone to make comparison of evaluation results obtained by CMCA.Then the availability and validity of CMCA is verified.Meanwhile,difference of CS based ED and classical ED is analyzed.Two new clustering analysis methods are introduced to make comparison with CMCA.Then the ability of proposed CMCA to meet evaluation requirements of ventilation system is verified. 展开更多
关键词 ventilation system underground metal mine alpine region cloud model cloud similarity Euclidean distance
在线阅读 下载PDF
基于FAHP-CM的舰船电力系统韧性评价研究 被引量:2
10
作者 王宇江 狄鹏 +3 位作者 侯丙旭 梁俊鹏 赵耀 陈俊源 《现代防御技术》 北大核心 2024年第5期138-146,共9页
针对当前评价舰船电力系统韧性具有较大的不确定性和主观性问题,在建立舰船电力系统韧性评价指标体系的基础上,将云模型(cloud model,CM)和模糊层次分析法(fuzzy analytic hierarchy process,FAHP)相结合,提出FAHP-CM的舰船电力系统韧... 针对当前评价舰船电力系统韧性具有较大的不确定性和主观性问题,在建立舰船电力系统韧性评价指标体系的基础上,将云模型(cloud model,CM)和模糊层次分析法(fuzzy analytic hierarchy process,FAHP)相结合,提出FAHP-CM的舰船电力系统韧性评价方法。该方法利用FAHP-CM计算评价指标的权重,使权重更加客观准确,同时简化计算过程,提高评估效率。实例分析结果表明,所建立的评价方法能够很好地反映舰船电力系统的韧性,并能有效解决评价的不确定性和主观性问题,使评价结果更加科学合理。 展开更多
关键词 舰船电力系统 韧性评价 云模型 模糊层次分析法 指标体系
在线阅读 下载PDF
Server load prediction algorithm based on CM-MC for cloud systems 被引量:2
11
作者 XU Xiaolong ZHANG Qitong +1 位作者 MOU Yiqi LU Xinyuan 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2018年第5期1069-1078,共10页
Accurate prediction of server load is important to cloud systems for improving the resource utilization, reducing the energy consumption and guaranteeing the quality of service(QoS).This paper analyzes the features of... Accurate prediction of server load is important to cloud systems for improving the resource utilization, reducing the energy consumption and guaranteeing the quality of service(QoS).This paper analyzes the features of cloud server load and the advantages and disadvantages of typical server load prediction algorithms, integrates the cloud model(CM) and the Markov chain(MC) together to realize a new CM-MC algorithm, and then proposes a new server load prediction algorithm based on CM-MC for cloud systems. The algorithm utilizes the historical data sample training method of the cloud model, and utilizes the Markov prediction theory to obtain the membership degree vector, based on which the weighted sum of the predicted values is used for the cloud model. The experiments show that the proposed prediction algorithm has higher prediction accuracy than other typical server load prediction algorithms, especially if the data has significant volatility. The proposed server load prediction algorithm based on CM-MC is suitable for cloud systems, and can help to reduce the energy consumption of cloud data centers. 展开更多
关键词 cloud computing load prediction cloud model Markov chain energy saving
在线阅读 下载PDF
CT-CloudDetect:用于遥感卫星云检测的混合模型
12
作者 方巍 陶恩屹 《遥感信息》 CSCD 北大核心 2024年第5期1-11,共11页
云检测是在遥感卫星云图中检测云的任务。近年来,人们提出了基于深度学习的云检测方法,并取得了良好的性能。然而,现有的基于深度学习的云检测模型大多还是基于卷积神经网络(convolutional neural network,CNN),由于卷积运算的固有局部... 云检测是在遥感卫星云图中检测云的任务。近年来,人们提出了基于深度学习的云检测方法,并取得了良好的性能。然而,现有的基于深度学习的云检测模型大多还是基于卷积神经网络(convolutional neural network,CNN),由于卷积运算的固有局部性,难以捕获长距离依赖关系。针对上述问题,文章提出一个基于CNN和ViT(Vision Transformer)的混合型云检测模型,并提出一种基于CNN和ViT的编码器,使网络具备捕捉局部和全局信息的能力。为了更好地融合语义和尺度不一致的特征,提出了一个双尺度注意力融合模块,通过注意力机制有选择地融合特征。此外,提出了轻量级路由解码器,该解码器通过路由结构降低模型复杂度。在3个公开云检测数据集上对模型进行了评估。大量实验表明,所提出的模型具有比现有模型更好的性能。 展开更多
关键词 深度学习 卷积神经网络 空间Vision Transformer 混合模型 云检测
在线阅读 下载PDF
基于CWM和CM的长滩露天矿深孔台阶爆破岩体可爆性评价 被引量:1
13
作者 史涵虚 周传波 +3 位作者 张升 马义全 蒋楠 田飞 《爆破》 CSCD 北大核心 2024年第1期51-59,119,共10页
在深孔台阶爆破中,对不同地质条件下的岩体按其可爆性进行分级,是进行爆破参数优选优化,确定合理爆破参数的前提,对提高矿区生产爆破效率,改善爆破效果、降低爆破成本具有重要意义。结合长滩露天煤矿爆破开挖实际,通过现场单孔爆破漏斗... 在深孔台阶爆破中,对不同地质条件下的岩体按其可爆性进行分级,是进行爆破参数优选优化,确定合理爆破参数的前提,对提高矿区生产爆破效率,改善爆破效果、降低爆破成本具有重要意义。结合长滩露天煤矿爆破开挖实际,通过现场单孔爆破漏斗试验、岩体声波测试、室内岩石力学试验,获取了岩体体可爆性分级相关指标。基于组合赋权(CWM)和云模型(CM)的可爆性分级方法,对长滩露天煤矿剥离岩体的可爆性进行了分级评价。结果表明长滩露天矿正在剥离爆破的4个平台岩体可爆性为:1130平盘主要分布灰绿色粗砂岩,可爆性为Ⅲ级(中等);1115平盘主要岩性为黄绿色中砂岩,可爆性为Ⅱ级(较难爆);1100平盘是紫红色砂质泥岩,可爆性为Ⅰ级(难爆);1145平盘主要以紫红色泥岩为主,可爆性为Ⅲ级(中等)。 展开更多
关键词 爆破漏斗试验 组合赋权 云模型 可爆性分级
在线阅读 下载PDF
Building a Tax Predictive Model Based on the Cloud Neural Network
14
作者 田永青 李志 朱仲英 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2003年第3期81-86,共6页
Tax is very important to the whole country, so a scientific tax predictive model is needed. This paper introduces the theory of the cloud model. On this basis, it presents a cloud neural network, and analyzes the main... Tax is very important to the whole country, so a scientific tax predictive model is needed. This paper introduces the theory of the cloud model. On this basis, it presents a cloud neural network, and analyzes the main factors which influence the tax revenue. Then if proposes a tax predictive model based on the cloud neural network. The model combines the strongpoints of the cloud model and the neural network. The experiment and simulation results show the effectiveness of the algorithm in this paper. 展开更多
关键词 cloud model Simplified TS cloud inference Neural network Tax predictive model.
在线阅读 下载PDF
基于CloudSim的电力系统计算云原生模型与仿真方法 被引量:3
15
作者 陈元榉 刘媛媛 +3 位作者 张延旭 蔡煜 胡春潮 蔡泽祥 《电力自动化设备》 EI CSCD 北大核心 2024年第9期189-196,204,共9页
分析基于云计算的电力系统计算过程是实现资源高效利用的基础。因此,提出一种基于CloudSim的电力系统计算的云原生建模与仿真方法。基于云原生技术阐述了电力系统计算架构的关键要素,提出基于CloudSim的电力系统计算架构的云原生模型,... 分析基于云计算的电力系统计算过程是实现资源高效利用的基础。因此,提出一种基于CloudSim的电力系统计算的云原生建模与仿真方法。基于云原生技术阐述了电力系统计算架构的关键要素,提出基于CloudSim的电力系统计算架构的云原生模型,分析电力云任务调配时的资源供需平衡问题。建立基于微服务的电力云任务模型,分析微服务的处理时序逻辑及其层级关系并生成微服务队列。据此提出微服务的动态调配模型,采用微服务-容器映射策略与实体动态整合策略,实现微服务在实体间的动态映射。利用CloudSim进行仿真分析,结果证明所提方法可行且有效,可为电力云计算的资源配置、任务调度等提供基本的仿真工具与方法。 展开更多
关键词 电力系统 cloudSim 云原生建模 电力系统计算架构 动态调配 时序逻辑 微服务队列
在线阅读 下载PDF
基于CM-FAHP的大变幅水位泵站取水方式比选 被引量:1
16
作者 刘俊华 童保林 +3 位作者 阳雯 李玲玲 董晓亮 刘志勇 《人民黄河》 CAS 北大核心 2024年第2期157-162,共6页
为提高大变幅水位泵站取水方式评价的合理性,建立一套大变幅水位泵站取水方式评价指标体系,将云模型(CM)与层次分析法(AHP)和熵权法(EWM)相结合,对各评价指标进行主客观组合赋权。提出基于CM和模糊层次分析法(FAHP)相结合的大变幅水位... 为提高大变幅水位泵站取水方式评价的合理性,建立一套大变幅水位泵站取水方式评价指标体系,将云模型(CM)与层次分析法(AHP)和熵权法(EWM)相结合,对各评价指标进行主客观组合赋权。提出基于CM和模糊层次分析法(FAHP)相结合的大变幅水位泵站取水方式综合评价方法,并采用云模型综合相似度比较法来确定最优取水方案。以云南省鲁地拉水资源综合利用置换洱海供水一期工程为例,进行实践应用。结果表明:4种取水方案(竖井干室型泵房、排架湿室型泵房、浮船式泵房和缆车式泵房)的综合评价云图均位于评价等级Ⅲ和Ⅳ标准云图之间,浮船式泵房的综合评价云图与Ⅳ标准云图的综合相似度最高,即浮船式泵房取水为最优方案。 展开更多
关键词 云模型 模糊层次分析法 组合赋权 大变幅水位 泵站 取水方式
在线阅读 下载PDF
基于CM-FCE-AHP的战时维修器材供应保障能力评价研究 被引量:4
17
作者 王金帼 王亚彬 +3 位作者 郭宇荣 王帅 赵建民 马飒飒 《兵工学报》 EI CAS CSCD 北大核心 2024年第3期1010-1024,共15页
战时维修器材供应保障具有高度的复杂性、随机性和动态性,导致战时维修器材供应保障评价的不确定性和模糊性。以战时维修器材供应保障任务与流程为依据构建保障能力评价指标体系,提出一种基于云模型的层次分析法和模糊综合评价方法,对... 战时维修器材供应保障具有高度的复杂性、随机性和动态性,导致战时维修器材供应保障评价的不确定性和模糊性。以战时维修器材供应保障任务与流程为依据构建保障能力评价指标体系,提出一种基于云模型的层次分析法和模糊综合评价方法,对战时维修器材供应保障能力进行客观评价。利用云模型对判断矩阵进行标度并聚合,得到指标权重,降低权重计算的主观性和随机性;利用云模型描述评价矩阵,得到隶属度矩阵。评价结果表明,指标体系能够很好地反映战时维修器材供应保障能力,改进的综合评价方法能有效解决战时维修器材供应保障能力评价中的高度模糊性和不确定性,提高评价结果的鲁棒性和客观性。 展开更多
关键词 战时维修器材供应保障 模糊综合评价 层次分析法 云模型 模糊性
在线阅读 下载PDF
Cloudless-Training:基于serverless的高效跨地域分布式ML训练框架
18
作者 谭文婷 吕存驰 +1 位作者 史骁 赵晓芳 《高技术通讯》 CAS 北大核心 2024年第3期219-232,共14页
跨地域分布式机器学习(ML)训练能够联合多区域的云资源协作训练,可满足许多新兴ML场景(比如大型模型训练、联邦学习)的训练需求。但其训练效率仍受2方面挑战的制约。首先,多区域云资源缺乏有效的弹性调度,这会影响训练的资源利用率和性... 跨地域分布式机器学习(ML)训练能够联合多区域的云资源协作训练,可满足许多新兴ML场景(比如大型模型训练、联邦学习)的训练需求。但其训练效率仍受2方面挑战的制约。首先,多区域云资源缺乏有效的弹性调度,这会影响训练的资源利用率和性能;其次,模型跨地域同步需要在广域网(WAN)上高频通信,受WAN的低带宽和高波动的影响,会产生巨大通信开销。本文提出Cloudless-Training,从3个方面实现高效的跨地域分布式ML训练。首先,它基于serverless计算模式实现,使用控制层和训练执行层的2层架构,支持多云区域的弹性调度和通信。其次,它提供一种弹性调度策略,根据可用云资源的异构性和训练数据集的分布自适应地部署训练工作流。最后,它提供了2种高效的跨云同步策略,包括基于梯度累积的异步随机梯度下降(ASGD-GA)和跨云参数服务器(PS)间的模型平均(MA)。Cloudless-Training是基于OpenFaaS实现的,并被部署在腾讯云上评估,实验结果表明Cloudless-Training可显著地提高跨地域分布式ML训练的资源利用率(训练成本降低了9.2%~24.0%)和同步效率(训练速度最多比基线快1.7倍),并能保证模型的收敛精度。 展开更多
关键词 跨地域分布式机器学习(ML)训练 跨云ML训练 分布式训练框架 serverless 跨云模型同步
在线阅读 下载PDF
激光三维点云在岩性语义分割中的应用综述 被引量:1
19
作者 邵燕林 刘浪 +4 位作者 曾齐红 胡忠贵 魏薇 邓帆 王庆 《科学技术与工程》 北大核心 2025年第4期1313-1324,共12页
激光三维扫描技术可快速获取扫描目标表面的点云数据,包括用于描述目标几何特征的空间点坐标和刻画目标材质反射率信息的激光反射强度。将激光三维点云的自动语义分割技术应用于地质勘探研究中,能为区域地质特征描绘奠定基础。为了展示... 激光三维扫描技术可快速获取扫描目标表面的点云数据,包括用于描述目标几何特征的空间点坐标和刻画目标材质反射率信息的激光反射强度。将激光三维点云的自动语义分割技术应用于地质勘探研究中,能为区域地质特征描绘奠定基础。为了展示激光三维扫描技术在地质场景大规模语义分割领域的最新进展,首先对摄影测量和激光雷达两种三维点云获取方式进行了比较,得到激光雷达在精度、泛用性、不易受光照条件影响等方面具有优势。通过阐述岩性语义分割的原理,将近年来基于几何特征或强度特征的岩性点云分割方法进行了全面的归纳和总结;介绍了常用大规模点云数据集和评价指标,并比较不同算法分割性能;最后总结了现有方法的局限性,并指出岩性语义分割任务未来研究方向进行展望。 展开更多
关键词 三维激光雷达 数字模型 点云语义分割 岩性分类
在线阅读 下载PDF
中国核桃出口增长驱动因素研究 被引量:1
20
作者 白丽 杨璇 李锐凯 《中国油脂》 北大核心 2025年第7期1-7,26,共8页
中国是世界核桃主要的生产国和出口国,自2019年来,中国的核桃出口量和出口额稳居世界前三。为进一步发掘中国核桃出口潜力,在对中国核桃出口贸易现状分析的基础上,运用国际市场占有率、贸易竞争力指数和显示性比较优势指数3个贸易指标... 中国是世界核桃主要的生产国和出口国,自2019年来,中国的核桃出口量和出口额稳居世界前三。为进一步发掘中国核桃出口潜力,在对中国核桃出口贸易现状分析的基础上,运用国际市场占有率、贸易竞争力指数和显示性比较优势指数3个贸易指标对中国和其他5个核桃主要出口国家的国际竞争力水平进行比较,并采用恒定市场份额(CMS)模型对2013—2022年中国核桃出口增长驱动因素进行分析,并由此提出建议。结果表明,中国核桃出口整体呈上升趋势,其中:带壳核桃和核桃仁的出口额均呈波动式上升趋势,带壳核桃增长较快;带壳核桃的出口市场较少,主要集中在中亚,而核桃仁的出口市场较为广泛,主要分布在亚洲和欧洲。2018—2022年,中国核桃的国际市场占有率逐渐增强,贸易竞争力指数介于0~1之间且逐渐趋向于1,显示性比较优势指数大部分小于0.8,说明我国核桃国际竞争力较弱,但在逐步增强。CMS模型分析表明,竞争力效应是影响中国核桃出口的主要因素。基于此,提出我国应优化市场结构、扩大核桃出口规模,科学生产核桃、提高国际竞争力,发展核桃精深加工、延长产业链条等建议。 展开更多
关键词 中国核桃 国际竞争力 cmS模型 出口增长
在线阅读 下载PDF
上一页 1 2 184 下一页 到第
使用帮助 返回顶部