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随着数字媒介的崛起与媒介形态的快速更替,美国传统媒介素养教育举步维艰。为迎接后真相时代的严峻挑战,一场由政府、媒介素养教育组织、教育工作者、高校、新闻界等多元主体共同参与的数字媒介素养教育全面启动。数字媒介素养教育可以帮助年轻人识别数字媒介的不利影响,帮助他们养成探究的习惯和表达技巧,将他们培养成为批判性的思想者、有效的沟通者和积极的公民。当前中国同样备受谣言、假消息的困扰,公众的媒介素养亟待提高。借鉴美国数字媒介素养教育的经验,应尽快将数字媒介素养教育纳入正规教育体系,制定数字媒介素养教育的整体教学规划,鼓励与发展数字媒介素养社会组织,高度重视家庭数字媒介素养教育的作用。 相似文献
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软件缺陷定位的有效性和及时性是提升软件质量的关键因素,现有自动缺陷定位方法和手工调试方法具有一定局限性。为解决这一问题,基于高斯过程的缺陷定位方法和软件自动修复对缺陷定位的有效性评估机制,设计了一种新的面向安全攸关系统的缺陷定位框架。基于ManyBugs和 IntroClass设计了软件缺陷定位测试数据集构造方法和实验方案。实验结果表明,该设计方案有效可行。 相似文献
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《Journal of The Franklin Institute》2019,356(13):7183-7209
With the rapidly increasing penetration level of power generated by large scale photovoltaic (PV) units into the power systems, the effect of the variable output power of the PV unit on the stability of the system cannot be ignored. This paper presents a mathematical approach to study the effect of high infiltration of PV power plant on the small signal stability of a power network and design of optimal fractional order PID (PIλDμ) controller for improving the probabilistic small signal stability of the power systems, taking into consideration the uncertainty of system operating conditions. Due to the probabilistic characteristics of large scale PV power generation, deterministic analysis approaches are not able to fully reveal the impact of high-level PV penetration. At first, this work introduces the main module and mathematical modeling of the large scale PV generation jointly with the single-machine infinite-bus power system. In the following, the paper proposes an efficient method that tunes power system stabilizer (PSS) to have the robustness for damping electro-mechanical oscillations in power systems with incorporated random PV power. For this reason, a robust PSS based on hybridization of PIλDμ controller and Non-dominated Sorting Genetic Algorithm (NSGAII) is designed. This paper targets at finding the optimal gain scheduling of the PIλDμ through the use of the advanced heuristic optimization technique with two objective functions in PV-grid connected systems. The performance of the proposed NSGAII-based PIλDμ controller (NSGAII- PIλDμ) under different solar irradiation, temperature conditions and disturbances is tested. Simulation results illustrate that the model presented can be used in designing of essential controllers for large scale PV power plant. 相似文献
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基于生态系统服务供需关系的农业生态管理分区 总被引:2,自引:0,他引:2
生态系统服务是人类赖以生存和发展的基础,厘清生态系统服务供给与需求的关系并对其分区管控有助于提升人类福祉。本文针对如何表征农业生态系统服务供需状态及其空间异质性问题,采用基于LUCC的生态系统服务矩阵,构建供需匹配度和供需协调度2个指标,并对2015年河北省曲周县村级行政单元农业生态系统服务状态和可持续能力进行评判;运用局部空间自相关分析,以局部空间集聚特征为依据,通过空间叠加产生的组合类型划分曲周县的农业生态管理区,并提出针对分区的管理措施。研究结果表明:①供需匹配度和供需协调度指标能实现区域内农业生态系统服务的整体评价,且具有可应用性和普适性。②2015年曲周县生态系统服务供需匹配度和协调度空间差异明显。区域供需匹配度为1.0647,处于一般均衡等级,表明2015年曲周县生态系统服务供需处于均衡状态;区域供需协调度为0.8977,处于良好协调状态,表明区域生态系统服务可持续能力较高。③将曲周县339个村级行政单元划分为4个一级生态管理区和12个二级生态管理亚区。提出的管理措施如下:生态保育区实施严格保护,禁止大规模建设;生态培育区实施综合保护,提升投产效益;生态改良区实施综合改良,促使生态环境转好;生态重构区实施整体生态整治和针对性生态重构。该研究结果可为区域的生态系统服务精细化管理、差异化保护提供思路。 相似文献