新能源组合出力的置信区间估计

随着新能源的不断发展,电力系统中常涉及新能源组合出力的分布问题。文中综述了几种常见新能源出力的分布特性,基于其分布函数,给出了多种新能源组合出力的累积分布函数和概率密度函数,提出了求解新能源组合出力置信区间的2种算法:二分查找—数值积分法和基于拉丁超立方抽样的蒙特卡洛法。通过一个三组合出力的具体算例的分析可知,利用推导的公式能准确给出其组合出力的概率分布曲线。对于置信区间的计算,二分查找—数值积分法平均花费228.25s,但具有较高的计算精度,而抽样类方法计算时间均在1s以内。基于拉丁超立方抽样的蒙特卡洛法抽样1 000次的效果即可达到随机抽样10 000次的效果,且其所用的计算时间较少,平均误差低,是一种较好的计算方法。     

系统评价在岩体质量分级中的应用

介绍了传统质量分级指标的数量多,离散性大,权重不同,且国内分类多以某一级作为整个区域的质量级别,对于区域内岩体质量的变化缺乏描述。以Q分类法为主,引入系统评价和系统决策的相关知识,将随机分析和敏感度理论设计引入到岩体工程中,对岩体的质量进行评价。     

故障超立方体网络中的路由算法

针对超立方体结构的多处理机系统中存在故障的情况,提出了一个应用于超立方体网络的容错路由算法。该容错路由算法是基于局部信息的,只需要知道邻节点的状态,而无需知道整个网络的运行情况。对于给定的源节点和目的节点,路由算法均能够找到一条最优通路,并且可以预防死锁。模拟实验结果表明,路由算法所构造的路径长度接近于两个节点之间的最优路径长度。     

基于Copula理论和切片采样技术结合拉丁超立方抽样的概率潮流计算

为评估大规模新能源并网对电力系统概率潮流的影响,提出一种Copula理论、切片采样及拉丁超立方采样相结合的MCMC概率潮流计算方法。利用Copula理论建立计及输入变量相关性的概率分布模型,采用Kendall秩相关系数作为相关性测度,通过切片采样算法产生初始样本,引入拉丁超立方抽样技术对初始样本进行处理,提高算法的计算效率。以改造后的IEEE-14节点测试系统为算例,验证了文中方法的准确性和有效性,研究了风、光出力相关性对电力系统概率潮流的影响。结果表明风、光互补提高了系统运行的可靠性和经济性,考虑风、光相关性可以更合理地评估风、光并网对电力系统概率潮流的影响。     

基于回归分析的汽车扶手箱下盖板注射成型工艺优化

以汽车扶手箱下盖板为研究对象,研究了保压压力、保压时、冷却时间、模具温度以及注塑温度五个注塑工艺因素对大型薄壁塑料件翘曲变形的影响.利用拉丁超立方抽样设计试验方案,基于Moldflow软件确定浇口位置、设置浇注系统和冷却系统,并对注射成型过程进行模拟仿真.通过对25组试验进行回归分析获得二阶回归模型,并结合遗传算法全局...     

Optimal Computing the Chessboard Distance Transform on Parallel Processing Systems

Thedistance transform(DT) is an image computation tool which can be used to extract the information about the shape and the position of the foreground pixels relative to each other. It converts a binary image into a grey-level image, where each pixel has a value corresponding to the distance to the nearest foreground pixel. The time complexity for computing the distance transform is fully dependent on the different distance metrics. Especially, the more exact the distance transform is, the worse execution time reached will be. Nowadays, quite often thousands of images are processed in a limited time. It seems quite impossible for a sequential computer to do such a computation for the distance transform in real time. In order to provide efficient distance transform computation, it is considerably desirable to develop a parallel algorithm for this operation. In this paper, based on the diagonal propagation approach, we first provide anO(N²) time sequential algorithm to compute thechessboard distance transform(CDT) of anN×Nimage, which is a DT using the chessboard distance metrics. Based on the proposed sequential algorithm, the CDT of a 2D binary image array of sizeN×Ncan be computed inO(logN) time on the EREW PRAM model usingO(N²/logN) processors,O(log logN) time on the CRCW PRAM model usingO(N²/log logN) processors, andO(logN) time on the hypercube computer usingO(N²/logN) processors. Following the mapping as proposed by Lee and Horng, the algorithm for the medial axis transform is also efficiently derived. The medial axis transform of a 2D binary image array of sizeN×Ncan be computed inO(logN) time on the EREW PRAM model usingO(N²/logN) processors,O(log logN) time on the CRCW PRAM model usingO(N²/log logN) processors, andO(logN) time on the hypercube computer usingO(N²/logN) processors. The proposed parallel algorithms are composed of a set of prefix operations. In each prefix operation phase, only increase (add-one) operation and minimum operation are employed. So, the algorithms are especially efficient in practical applications.     

Minimizing Communication Penalty of Triangular Solvers by Runtime Mesh Configuration and Workload Redistribution

In this article, we study the effects of network topology and load balancing on the performance of a new parallel algorithm for solving triangular systems of linear equations on distributed-memory message-passing multiprocessors. The proposed algorithm employs novel runtime data mapping and workload redistribution methods on a communication network which is configured as a toroidal mesh. A fully parameterized theoretical model is used to predict communication behaviors of the proposed algorithm relevant to load balancing, and the analytical performance results correctly determine the optimal dimensions of the toroidal mesh, which vary with the problem size, the number of available processors, and the hardware parameters of the machine. Further enhancement to the proposed algorithm is then achieved through redistributing the arithmetic workload at runtime. Our FORTRAN implementation of the proposed algorithm as well as its enhanced version has been tested on an Intel iPSC/2 hypercube, and the same code is also suitable for executing the algorithm on the iPSC/860 hypercube and the Intel Paragon mesh multiprocessor. The actual timing results support our theoretical findings, and they both confirm the very significant impact a network topology chosen at runtime can have on the computational load distribution, the communication behaviors and the overall performance of parallel algorithms.     

基于超立方体的静态任务调度

该文给出一个基于超立方体的静态任务调度算法.在算法的设计中,首先建立了任务优先级表和处理机优先级表,任务在调度时总是顺次调度高优先级任务,然后再从处理机优先级表中选择能使该任务最早开始执行的处理机.最后,分别给出了基于LU分解的任务图与随机生成的任务图的调度结果.     

超立方体的谱

对于超立方体的谱问题,首先获得了ｎ－维超立方体Ｂ的特征多项式Ｐ（Ｂ＾ｎ;λ）的递推公式Ｐ（Ｂ＾ｎ＋１;λ）＝Ｐ（Ｂ＾ｎ＋１;λ＋）Ｐ（Ｂ＾ｎ;λ－）。在此基础上得到了ｎ－维超立体Ｂ＾ｎ的谱;