未来大数据环境下的配用电通信网虚拟网络架构及应用

根据智能配电网的通信需求,本文提出了基于无线 Mesh 网和电力线通信网的智能配电网通信框架。在此框架的基础上,设计了一个遗传算法和启发式算法,为不同类型的业务分别建立虚拟网络并将其映射到异构的物理网络中,通过增加传输分集来保证实时业务的可靠性。通过仿真,验证两种映射算法在保证实时业务可靠性的基础上,使尽力而为型业务的吞吐率达到最大化。     

浅谈110 kV变压器的维护与检修

作为电网的核心电气设备,变压器会对电网的运行产生重大影响。为了确保变压器的可靠、安全运行,电力企业需要对变压器进行日常维护与检修。阐述了变压器常见异常状况和日常维护的具体内容,以供参考。     

山西省近50年风速变化及突变特征分析

利用线性拟合、M-K方法对山西省22个气象观测站1960—2010年的逐日风速资料进行了倾向、突变、逐年代变化等特征分析。研究表明,近50年来山西省平均风速存在明显的下降趋势,平均风速由20世纪60年代的2.16 m/s下降到21世纪初的1.86 m/s;不同时间段呈现不同的变化特征,1979—1989年风速出现显著下降,年均递减率达到0.046 m/s,变率远超出其他时段;对近50年山西省平均风速进行M-K检验后发现,在1982年出现明显的突变点。山西省四季平均风速均呈下降趋势,四季风速下降速率最快的为春季,冬季次之,夏季风速下降速率最慢。同样,四季风速均发生突变,突变时间点分布在1980—1985年间。除8月外,山西省各个月份风速也呈下降趋势,且均出现突变现象。     

二阶自治广义Birkhoff系统的奇点分析

建立二阶自治广义Birkhoff系统的微分方程.给出该系统的线性化方程,得到该线性方程转化为梯度系统的条件,利用梯度系统的性质对线性系统的奇点进行了分析,然后再利用Perron定理探讨了相应的非线性系统的奇点类型.结果表明,如果线性系统能成为梯度系统,那么相应的非线性系统的奇点可能是结点或者鞍点.     

Point-augmented biquadratic C1 subdivision surfaces

Shape artifacts, especially for convex input polyhedra, make Doo and Sabin’s generalization of bi-quadratic (bi-2) subdivision surfaces unattractive for general design. Rather than tuning the eigenstructure of the subdivision matrix, we improve shape by adding a point and enriching the refinement rules. Adding a guiding point can also yield a polar bi-2 subdivision algorithm. Both the augmented and the polar bi-2 subdivision are complemented by a new Primal Bi-2 Subdivision scheme. All surfaces are $C^1$ and can be combined.     

On the Controllability of Nonlocal Second‐Order Impulsive Neutral Stochastic Integro‐Differential Equations with Infinite Delay

In this paper, we investigate the controllability for a class of nonlocal second‐order impulsive neutral stochastic integro‐differential equations with infinite delay in Hilbert spaces. More precisely, a set of sufficient conditions for the controllability results of nonlocal second‐order impulsive neutral stochastic integro‐differential equations with infinite delay are derived by means of the Banach fixed point theorem combined with theories of a strongly continuous cosine family of bounded linear operators. As an application, an example is provided to illustrate the obtained theory.     

太阳能LED路灯控制系统的设计

设计了一套基于STC12单片机的太阳能LED路灯控制系统,系统采用变步长的电导增量法跟踪太阳能电池板最大功率点,充分利用太阳能电池板的能量,对铅酸蓄电池充电。同时实时监测铅酸蓄电池的电压防止蓄电池过充、过放等现象;对LED路灯采用多段式的恒流控制,通过环境照度的监测控制LED路灯在不同电流强度下工作,以增强LED路灯的使用寿命,实现节约用电的目的。     

用于迷宫电脑鼠的一种迷宫补全算法

摘要：在IEEE电脑鼠走迷宫竞赛规则的基础上,介绍了一种基于对迷宫分析补全思想的路径规划算法。详细阐述了算法流程和实现过程,对搜索过程中的算法提出一种改进思想。实验表明,该算法可以提高电脑鼠的搜索效率,有效地减少迷宫搜索时间,提高竞赛成绩。     

Complete controllability for abstract measure differential systems

In this paper, we investigate the complete controllability for abstract measure differential systems. Firstly, we introduce several new concepts about complete controllability for abstract measure differential systems. Then, on the basis of the Sadovskii fixed‐point theorem, we give sufficient conditions for complete controllability for a class of abstract measure differential systems. The compactness of the semigroup generated by some operator is unnecessary in this paper, and we show that our results, dealing with complete controllability problem for an ordinary differential system in infinite‐dimensional Banach space, are also less conservative than that in the previous literature. Copyright © 2012 John Wiley & Sons, Ltd.     

Federated Searching

ABSTRACT

With an increasing number of libraries implementing federated searching to help users negotiate the complex electronic database environment, it is important to note how users are being instructed to use these resources. This article presents the results of examinations of the Web sites of Association of Research Libraries (ARL) member institutions that currently use federated search products. It analyzes help guides and search tips related to federated searching to determine what concepts are being explained to users and how the information is being communicated. The result of the evaluation of these Web sites is a list of “best practice” guidelines that may be used by librarians creating their own federated searching guides. doi:10.1300/J136v12n03_03