计及老化线路电流承载能力退化特性的电力系统连锁故障分析

长期老化效应导致输电线路的电流承载能力退化以及老化失效风险增大,会使连锁故障风险进一步恶化。研究了输电线路老化对电力系统连锁故障的影响。首先,基于热平衡理论建立了输电线路老化相依的电流承载能力计算模型,阐述了电流承载能力与输电线路运行年龄的数值对应关系。在此基础上,综合考虑实时潮流和输电线路的老化效应,建立了包含实时潮流、运行年限、停运概率的三维映射关系,改良了输电线路动态停运概率模型。然后,通过引入概率阈值参数,建立一种改进的基于停运概率模型的连锁故障路径搜索准则,以连锁故障演化过程中的最大概率耦合事件为导向,在过滤低概率连锁故障路径的同时筛选代表性故障路径。最后,在改进的IEEE 39节点系统上进行了实例研究。算例结果证明,考虑线路老化效应后,由单线路意外事件触发的连锁故障事件增多,概率增大,其对应路径阶数增大,系统连锁故障风险明显升高,表明输电线路老化效应与连锁故障后果之间存在显著相关性。     

Long Duration Persistent Photocurrent in 3 nm Thin Doped Indium Oxide for Integrated Light Sensing and In-Sensor Neuromorphic Computation

Miniaturization and energy consumption by computational systems remain major challenges to address. Optoelectronics based synaptic and light sensing provide an exciting platform for neuromorphic processing and vision applications offering several advantages. It is highly desirable to achieve single-element image sensors that allow reception of information and execution of in-memory computing processes while maintaining memory for much longer durations without the need for frequent electrical or optical rehearsals. In this work, ultra-thin (<3 nm) doped indium oxide (In₂O₃) layers are engineered to demonstrate a monolithic two-terminal ultraviolet (UV) sensing and processing system with long optical state retention operating at 50 mV. This endows features of several conductance states within the persistent photocurrent window that are harnessed to show learning capabilities and significantly reduce the number of rehearsals. The atomically thin sheets are implemented as a focal plane array (FPA) for UV spectrum based proof-of-concept vision system capable of pattern recognition and memorization required for imaging and detection applications. This integrated light sensing and memory system is deployed to illustrate capabilities for real-time, in-sensor memorization, and recognition tasks. This study provides an important template to engineer miniaturized and low operating voltage neuromorphic platforms across the light spectrum based on application demand.     

Ultraviolet photodetectors and readout based on a-IGZO semiconductor technology

In this work, real-time ultraviolet photodetectors are realized through metal–semiconductor–metal (MSM) structures. Amorphous indium gallium zinc oxide (a-IGZO) is used as semiconductor material and gold as metal electrodes. The readout of an individual sensor is implemented by a transimpedance amplifier (TIA) consisting of an all-enhancement a-IGZO thin-film transistor (TFT) operational amplifier and a switched capacitor (SC) as feedback resistance. The photosensor and the transimpedance amplifier are both manufactured on glass substrates. The measured photosensor possesses a high responsivity R , a low response time t _{R E S} , and a good noise equivalent power value NEP .     

海战场态势生成技术发展综述

未来的战争必将是多兵种、多域联合作战,战场态势作为未来联合作战的重要支撑,旨在为联合作战提供精准、高效的统一态势图,而如何将多平台、同/异构传感器信息及其他情报信息与战场环境融合生成准确可靠的战场态势是亟需解决的技术难题。鉴于现代海战场对高精度、强实时、全要素战场态势图的迫切需求,对海战场态势生成技术进行了综述。首先梳理了海上态势生成项目的发展历程及能力水平;然后详细介绍了通用作战图/通用战术图等典型项目,在态势生成部分中通过态势图的要素组成、态势生成流程及关键技术对态势生成技术进行了阐述;最后对未来海战场态势生成技术的发展趋势进行了预测,希望可以为态势生成相关研究提供参考。     

基于改进旗鱼算法的综合能源系统能量管理

综合能源系统在实现可再生能源利用中具有重要价值。为使系统中各设备出力得到进一步优化,将生物质能与综合能源系统相结合,并且将各个时刻的柔性负荷纳入能量调度,构建了一种沼气发电系统、光伏发电系统与微型燃气轮机驱动下的源-储-荷协同多目标能量管理模型。以系统与主电网的交互及燃料费用、惩罚费用和设备投资及运行费用为优化目标,以用户综合用能满意度、新能源利用率和电能自治程度为评价指标,求解模型最优配置。利用非线性攻击方式、差分变异策略、哈里斯鹰算法中的软包围策略及防止算法停滞策略来改善旗鱼算法的全局搜索能力。通过算例对比分析表明,所提出的改进算法和能量管理模型在不同场景下均有效地提高了经济效益和环保效益,并且改进旗鱼算法在全局寻优和搜索精度等方面具有优势。     

Markov chain Monte Carlo in Bayesian models for testing gamma and lognormal S-type process qualities

The process capability index C_pu is widely used to measure S-type process quality. Many researchers have presented adaptive techniques for assessing the true C_pu assuming normality. However, the quality characteristic is often abnormal, and the derived techniques based on the normality assumption could mislead the manager into making uninformed decisions. Therefore, this study provides an alternative method for assessing C_pu of non-normal processes. The Markov chain Monte Carlo, an emerging popular statistical tool, is integrated into Bayesian models to seek the empirical posterior distributions of specific gamma and lognormal parameters. Afterwards, the lower credible interval bound of C_pu can be derived for testing the non-normal process quality. Simulations show that the proposed method is adaptive and has good performance in terms of coverage probability.     

A short note on the effect of sample size on the estimation error in Cp

Process capability indices such as C_p are used extensively in manufacturing industries to assess processes in order to decide about purchasing. In practice, the parameter for calculating C_p is rarely known and is frequently replaced with estimates from an in-control reference sample. This article explores the optimal sample size required to achieve a desired error of estimation using absolute percentage error of different C_p estimates. Moreover, some practical tools are created to allow practitioners to find sample size in different situations.     

Managing sequential ambidexterity in the electronics industry: roles of temporal switching capability and contingent factors

Researchers on organisational ambidexterity have proposed several solutions to address the potential conflicts between exploration activities and exploitation activities. Unlike simultaneous ambidexterity, sequential ambidexterity – defined as temporal switching between exploration and exploitation – has not been examined fully, and the conditions under which this temporal switching can be successful are unclear. This paper proposes the concept of temporal switching capability to better understand the process by which sequential ambidexterity is executed. In addition, we hypothesise that performance effects are contingent upon firm-specific factors: a firm’s business strategy and absorptive capacity. Utilising three sources of data – a secondary database, annual reports and a survey administered to 145 firms in the electronics industry with 10-year observations – we find support for our hypotheses. The results show that the temporal switching capability positively relates to new product performance and that business strategy type and absorptive capacity have moderating effects. The results are meaningful in both theory and practice.     

基于能力培养的民办高校软件工程专业课程体系研究

提高教学质量是民办高校可持续发展的有效途经。本文以黄河科技学院软件工程专业为研究对象,结合本校"本科学历教育与职业技能教育相结合"的人才培养模式,讨论民办教育应用型软件人才培养方式。论文首先对软件工程专业社会需求和就业现状进行分析;然后探讨软件工程专业人才培养的专业能力和能力点;最后,围绕以能力培养为目标详细论述软件工程专业的课程体系设置,使民办高校培养的学生既有专业应用能力,又有创新思维和创业能力,以满足社会需求。