The optimal event-triggered impulsive control of a stochastic rumor spreading model incorporating time delay using the particle swarm optimization algorithm     

《Journal of The Franklin Institute》2023,360(7):4695-4718

In the digital age, rumor spreading is becoming more widespread and faster than ever before, and results in the more social panic and instability. Because of this, it is crucial to implement effective control strategies to prevent the continued spread of rumors, and avoid all kinds of unnecessary harm caused by rumors. In this paper, a stochastic rumor spreading model incorporating time delay within the framework of the event-triggered impulsive control (ETIC) strategies are presented. To begin with, the stability problem of this model is discussed and proved. Besides, the optimal ETIC strategies are explored by the particle swarm optimization (PSO) algorithm. Furthermore, some numerical simulations are performed to illustrate the optimal ETIC strategies of the given model. In addition, a real case is used to prove the validity of given model. Finally, the following conclusions are drawn that the stochastic model is feasible and consistent with actual rumor propagation trends, and ETIC strategies can help control rumors effectively. Meanwhile, different ETIC strategies should be used according to the different situations of rumor spreading. For instance, control strategies need to be more frequent and robust when transmission rates are higher or time delay are shorter.  相似文献   

Nonlinear process monitoring based on generic reconstruction-based auto-associative neural network     

《Journal of The Franklin Institute》2023,360(7):5149-5170

A significant concern with statistical fault diagnosis is the large number of false alarms caused by the smearing effect. Although the reconstruction-based approach effectively solves this problem, most of them only focus on linear rather than nonlinear systems. In the present work, a generic reconstruction-based auto-associative neural network (GRBAANN) is proposed that uses the reconstruction-based approach to isolate simple and complex faults for nonlinear systems. Nevertheless, in GRBAANN, it is challenging to acquire a trivial solution for the reconstruction-based index, which is equivalent to a complex vector fixed-point problem. In this regard, the Steffensen method is employed to deal with this problem with an accelerated iterative process, which is appropriate for both single and multiple variable faults. The variable selection procedure is time-consuming but imperative for reconstruction-based approaches, with no exception to the proposed method. In order to ensure the real-time diagnosis for large-scale systems, the Sequential floating forward selection method with memory is proposed to minimize the computation time of the variable selection procedure. The effectiveness of the proposed GRBAANN scheme is illustrated through a validation example and an industrial example. Comparisons with the state-of-art methods are also presented.  相似文献   

海上风能等级区划研究：瓶颈与对策          下载免费PDF全文

郑崇伟  李崇银 《中国科学院院刊》2023,38(4):654-665

海上风能等新能源是实现碳达峰、碳中和（以下简称“双碳”）目标的重要支撑,其资源合理等级区划是资源布局和选址的关键依据。文章首先梳理国内外海上风能等级区划的研究进展,剖析传统区划方案需要改进的6个方面：未能兼顾环境风险和成本效益,资源等级的区域差异不显著,难以满足多样化开发需求,在部分月份不适用,对未来风能等级预估不足,区划结果与机理不符。针对上述问题,采用气候统计方法,提出全要素、全时节、全海域、动态自适应的风能等级区划理念,以及绘制风能等级动态图谱的应对措施,以解决资源开发的宏观战略布局、微观精准选址、长期科学规划难题。期望本研究可以推动海上风能的产业化、规模化、自主化的高质量建设,助力我国“双碳”目标实质化、深层化。  相似文献   

Linkages revisited. Higher education and development cooperation—An assessment: Edited by Willem-Jan de Gast. 470 pp. Nuffic (Netherlands Organization for International Cooperation in Higher Education), The Hague. n.d.     

《Higher Education Policy》1997,10(1):93-94

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构建自立自强的海洋科学观测探测技术体系的思考          下载免费PDF全文

吴园涛  任小波  段晓男  文质彬  董丹宏  殷建平  沙忠利  赵宏宇  蒋磊  江丽霞  沈刚 《中国科学院院刊》2022,37(7):861-869

海洋是国家战略必争领域，建设海洋强国必须要提高海洋资源开发能力，发展海洋经济，保护海洋生态环境，坚决维护国家海洋权益。推动海洋科技实现高水平科技自立自强，是加快建设海洋强国的必然要求。海洋观测探测技术是认识海洋的基本手段，是海洋资源开发、环境保护和权益维护的重要基础。文章回顾了全球和我国海洋观测探测计划和观测网络取得的重要进展，重点介绍了中国科学院海洋科学观测探测技术体系构建的实践，并对下一步发展提出了思考和展望。构建自立自强的海洋科学观测探测技术体系，要进一步加强顶层设计，推动国家战略需求和科技前沿问题“双引擎”；强化科技攻关，瞄准最紧急、最紧迫的关键问题持续发力；创新体制机制，充分发挥海洋领域国家战略科技力量作用，为我国海洋强国建设提供强有力的科技支撑。  相似文献   

《巴黎协定》温控目标下未来碳排放空间的准确估算问题辨析          下载免费PDF全文

周天军  陈晓龙 《中国科学院院刊》2022,37(2):216-229

为了应对工业化以来的全球增暖问题，《联合国气候变化框架公约》缔约方通过《巴黎协定》设定了“将全球平均气温较前工业化时期上升幅度控制在2℃以内，并努力将温度上升幅度限制在1.5℃以内”的目标。当前，全球平均表面温度相对工业革命前的升温已超过1℃，累积二氧化碳（CO₂）排放达到2 390 Gt。因此，要实现《巴黎协定》的1.5℃和2℃温控目标，需要准确估算未来剩余的碳排放空间。文章在概述地球系统碳循环与升温关系的基础上，对未来碳排放空间的估算方法进行评述，分析讨论了政府间气候变化专门委员会（IPCC）第六次评估报告（AR6）和IPCC第五次评估报告（AR5）发布以来在碳排放空间估算方面的国际研究进展，探究了造成估算结果差异的原因并指出影响未来碳排放空间估算准确性的关键因素。最后，围绕未来碳排放空间的准确估算问题，提出了亟待加强的研究领域。文章可为科学界在温控目标下准确估算未来碳排放空间核算数据及未来的研究重点方向提供参考。  相似文献