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1.
In future power grids where electricity flows bidirectionally, the essential problem is to maximize the total efficiency of distributed energy resources. In complicated and large‐scale systems such as modern power distribution networks, maximizing the efficiency of the entire system as a whole is extremely difficult. To solve the global optimization problem of such a complex network, this paper proposes an efficient distributed control method for future grid on the basis of tie‐set graph theory, where a tie‐set is a set of all the edges in a loop of a graph. On the basis of tie‐set graph theory, global optimization of an entire network can be realized as a result of local optimization in μ‐dimensional liner vector space, where μ is the nullity of the underlying graph of a power network. Although each tie‐set has its limited local information, an entire network is gradually optimized in an orderly manner because of the theoretical basis of a tie‐set graph. Simulation results of several thousand‐node networks demonstrate balanced allocation of dispersed energy resources and thus effectiveness of the proposed method. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
2.
A new and straightforward design procedure for simple canonical topologies of allpole, active‐RC, low‐selectivity band‐pass (BP) filters, with low sensitivity to component tolerances is presented. The procedure is primarily intended for discrete‐component, low‐power filter applications using just one amplifier for relatively high‐order filters. The design procedure starts out with an ‘optimized’ low‐pass (LP) prototype filter, yielding an ‘optimized’ BP filter, whereby the wealth of ‘optimized’ single‐amplifier LP filter designs can be exploited. Using a so‐called ‘lossy’ LP–BP transformation, closed‐form design equations for the design of second‐ to eighth‐order, single‐amplifier BP filters are presented. The low sensitivity, low power consumption, and low noise features of the resulting circuits, as well as the influence of the finite gain‐bandwidth product and component spread, are demonstrated for the case of a fourth‐order filter example. The optimized single‐opamp fourth‐order filter is compared with other designs, such as the cascade of optimized Biquads. Using PSpice with a TL081 opamp model, the filter performance is simulated and the results compared and verified with measurements of a discrete‐component breadboard filter using 1% resistors, 1% capacitors, and a TL081 opamp. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   
3.
Generation reserves are needed to maintain the real time balance between power supply and power demand. Because power is noninventoriable, power generation follows power demand. Demand for power varies considerably depending on the time of day, day of the week and season. The predictable portion of power demand is met by purchasing firm energy on a day ahead or real time market. The random unpredictable portion of demand is met by purchasing a set of online and offline generation reserves on an ancillary market. The total energy purchasing cost includes payments for firm energy and payments for generation reserves. The latter include fixed capacity payments for reserve generation capacities and variable payments for the random energy produced from these reserves. The main contribution of this paper is to present an optimization model that captures the dynamism in the selection of the dispatch interval to determine the amount of firm energy and reserve capacities given a set of market prices. This is done by explicitly including in the model the duration of the dispatch period and the frequency this decision is reevaluated. In this model the randomness of the demand is captured by using a Doubly Truncated Normal Distribution. The cost incurred to activate generation reserves is modeled as a Poisson process. The total model captures the price differences from using different reserve sources. An empirical example is presented to illustrate the cost benefits of using the method proposed in this research with two different strategies: a static strategy and a dynamic strategy. It is shown that dynamically setting generation reserves results in cost savings.  相似文献   
4.
This paper presents a novel model for optimal coordinated voltage emergency control (OCVEC). It takes account of the dynamics of loads and discrete/continuous nature of controls with coordination of dissimilar controls at different geographical locations in order to keep the desired voltage profiles against voltage collapse during an emergency. An integration index of the bus voltage deviation is adopted as the voltage stability performance index. The sensitivities of this performance index with respect to controls are derived using the optimal control theory. Since the sensitivities can be evaluated using the fast quasi-steady-state time domain simulation results, the intractable OCVEC model can be transformed into a tractable problem of quadratic programming. The effectiveness of the proposed model and its solution strategy is validated by case studies on the New England 39-bus and Nordic 32 power systems.  相似文献   
5.
Android安全加固技术   总被引:1,自引:0,他引:1  
为了保护Android智能手机安全,在深入分析Android系统安全机制的基础上,提出了一个基于强制访问控制的安全加固技术.该技术首先通过修改Android内核,添加一个平台无关的强制访问框架,其次为进程、文件等系统对象添加安全属性,最后通过制定一套细粒度的强制访问规则,对应用程序实施强制访问控制.通过在模拟环境中的测...  相似文献   
6.
基于模糊理论的随机需求系统   总被引:1,自引:0,他引:1  
需求量是供销系统成本优化中的重要指标.目前常见的研究方法是采用泊松分布来拟合.通过数据统计和分析,我们发现采用模糊三角去拟合随机需求量有更好的拟合度和科学性.采用模糊理论对随机需求进行了建模分析,设计了随机需求系统的算法并最终对其进行了实现.  相似文献   
7.
基于OpenGL的新型水雷三维仿真训练系统   总被引:1,自引:0,他引:1  
为克服我国新型水雷开展训练面临的困难,介绍了采用Visual C++及OpenGL构建某型水雷三维仿真训练系统的方法和过程.重点阐述了如何在OpenGL开发环境中实现对三维模型的交互控制.训练系统的建立证明了方法的可行性.  相似文献   
8.
以某污水厂集控系统为背景,介绍了基于组态软件Intouch的污水厂自动化系统监控软件的设计,较为详细地介绍了该监控软件中的监控界面、数据通信、数据存储与输出和撤表系统等技术的设计与实现.实践证明该系统可以精确稳定地运行.  相似文献   
9.
基于行为的机器人自适应队形控制   总被引:1,自引:0,他引:1  
针对多机器人在未知复杂环境下的队形控制问题,将leader-follower法结合到基于行为法中,提出了机器人在复杂环境下采取跟踪链的方式穿越障碍,而后再重新组队,使机器人适应环境的能力增强,避免了机器人在复杂环境下掉队的现象.在避障活动障碍时,依据障碍运动趋势有预见的主动避开,使控制行为既简单又有效,仿真结果表明该队...  相似文献   
10.
随着移动技术以及数字化技术的飞速发展和广泛应用,各类便携式、多功能、可移动智能终端的普及人们对移动学习和移动办公提出了更高的要求,建设新一代支持移动学习的无线校园网应运而生.研究支持移动学习的无线校园网建设规划和设计,探讨无线校园网IPv6的支持,并提出移动学习应用需求.  相似文献   
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