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141.
随着数字化的高速发展,各项关键基础设施和重要资源对供应链越来越依赖,网络罪犯和黑客也已发现供应链里面充满了可供利用的漏洞,不少国家政府已经表示对供应链的完整性和脆弱性越来越担忧。从APT供应链攻击的原理和检测难点进行分析,并借鉴各国政府、国外企业采取的措施着手,从政策、技术、安全意识培养等方面对我国APT供应链攻击防护和应对提出相关建议。 相似文献
142.
本文主要论述Z190F型风冷直喷式柴油机研制的设计思想、技术参数、结构特点、试验研究和研制结果,并对后续工作作了展望。 相似文献
143.
144.
Yu‐Wei Zhang Jing Wu Zhongping Ji Mingqiang Wei Caiming Zhang 《Computer Graphics Forum》2019,38(2):521-534
As an art form between drawing and sculpture, relief has been widely used in a variety of media for signs, narratives, decorations and other purposes. Traditional relief creation relies on both professional skills and artistic expertise, which is extremely time‐consuming. Recently, automatic or semi‐automatic relief modelling from a 3D object or a 2D image has been a subject of interest in computer graphics. Various methods have been proposed to generate reliefs with few user interactions or minor human efforts, while preserving or enhancing the appearance of the input. This survey provides a comprehensive review of the advances in computer‐assisted relief modelling during the past decade. First, we provide an overview of relief types and their art characteristics. Then, we introduce the key techniques of object‐space methods and image‐space methods respectively. Advantages and limitations of each category are discussed in details. We conclude the report by discussing directions for possible future research. 相似文献
145.
针对当前机场逐步实行车辆“油改电”的大背景,研究了在今后机场全面推行电动特种车辆的情况下,机场充电桩的布局规划问题。建立了以充电桩管理和建设费用、电动特种车辆路上运行费用及充电等待费用最小为目标函数的充电桩选址模型,分析了电动特车的机场运行流程,在此基础上提出了遗传算法作为模型求解方法,对各算法参数进行标定,潜在地增加了种群的多样性及全局寻优能力。结合机场实例,对模型和算法进行了仿真分析,确定了该机场充电桩布局选址的最终方案,证明了模型的可行性和算法的有效性。 相似文献
146.
Improved crystallizability and processability of ultra high molecular weight polyethylene modified by poly(amido amine) dendrimers
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Tairong Kuang Lingqian Chang Dajiong Fu Jintao Yang Mingqiang Zhong Feng Chen Xiangfang Peng 《Polymer Engineering and Science》2017,57(2):153-160
Ultrahigh molecular weight polyethylene (UHMWPE) is usually difficult to be melt processed due to severe intermolecular entanglement in its melt. In this work, we reported the development of a poly(amido amine) (PAMAM) dendrimer (G1) and its derivatives with different terminal groups which showed promising feasibility for aiding UHMWPE melt processing. The rheological, crystalline, and mechanical properties of the blends were investigated comprehensively. The addition of the dendritic modifiers to the UHMWPE matrix resulted in a significant decrease in melt viscosity, thus an obvious enhancement of the processability. The dynamic analysis of the mechanical properties and rotation‐rheological test indicated a disentanglement effect of the UHMWPE melt molecules was generated by the PAMAM dendrimer (G1) and its derivatives. Furthermore, the PAMAM dendrimer (G1), as an internal lubricant, was uniformly distributed in the UHMWPE matrix. The heteronucleation effect of the PAMAM dendrimer (G1) with its derivatives led to a higher degree of crystallinity, smaller crystallites in the matrix and enhanced tensile strength in the UHMWPE blends. POLYM. ENG. SCI., 57:153–160, 2017. © 2016 Society of Plastics Engineers 相似文献
147.
高比例风电并网下基于卡尔多改进的深度调峰机制 总被引:2,自引:0,他引:2
针对高比例风电并网下深度调峰中涉及的利益分配问题,在分析资源配置原则与不同类型电源调峰特性的基础上,提出基于卡尔多改进的风火复合系统深度调峰新机制,探讨通过调整参与者利益分配挖掘系统深度调峰潜力的实现方法。以纯凝、热电和风电三类机组为典型代表,分析其机组效益与约束条件表达,并在目标函数中增加补偿与分摊项,由此建立引入卡尔多改进机制的深度调峰数学模型。根据最优化条件和经济学原理,探究该模型中机组效益受补偿与分摊影响的变化规律,揭示卡尔多改进下深度调峰的决策机理。进一步建立了一种方便工程实现的机组补偿费用与分摊费用的分档确定原则,从而克服了求解基于卡尔多改进深度调峰数学模型的困难。算例仿真验证了新机制提高风电消纳的有效性和调整利益分配的合理性。 相似文献
148.
建立办公室的CFD模型,以雷诺平均方程和k-ε两方程紊流模型为基础,应用Monte Carlo法,考虑太阳辐射产生附加热流的影响,研究了室内速度分布、温度场、PMV值及PM2.5浓度场。计算结果和实验数据表明:该仿真模型能准确计算室内热环境,散流器送风不合理,风速分布不均,导致PMV值偏大,人体会感觉较热,需要进一步优化送风口的风速或开度大小;室内温度均值在26.15 ℃,上下浮动不超过±2 ℃,温度分布均匀,但电脑、人体和荧光灯散热对其附近温度场分布有影响;PM2.5含量为良,室内物品表面细微颗粒对PM2.5的浓度有一定影响。 相似文献
149.
A virtual enterprise is an emerging business cooperation model which allows rapid response to the unpredictable market behavior and opportunity. For service oriented enterprises, where computing resources are encapsulated as services and published online, establishing a virtual enterprise can be regarded as a process of service composition. As there are increasing numbers of available services providing similar functionalities but with different quality values, and with potential business correlations among them, it is not trivial to orchestrate a composite service with optimal overall quality of service (QoS). In this paper, we formally propose a business correlation model including both quality correlations and selection correlations, and then present an efficient approach for correlation-driven QoS-aware optimal service selection based on a genetic algorithm. The genetic algorithm is tailored with niching technology, a repair operator and a penalty mechanism. The effectiveness and efficiency of the approach are demonstrated via empirical studies at last. 相似文献
150.