有效资产管制条件下电网企业资产更换决策方法分析

在有效资产管制的条件下,电网企业为规避管制风险.必然采用适当的方法对其资产更换需求做出预测与决策,并使其资产更换数量尽可能与管制机构的评估数量相一致.针对现行的资产更换方法未能充分反映电网有效资产管制以及可靠性与经济性的特点,本文综合考虑上述三个要素,在分析现有电网资产更换的理论与方法的基础上.提出和分析了电网企业资产更换决策的评分法.本文认为,这种方法能够更加准确地分析和诊断资产健康状况,特别适用于电网企业资产的短中期更换数量的预测与决策,对电网企业大修、技术改造项目的合理安排也具有一定的借鉴价值.     

一种基于网格剖分的两点射线追踪方法

两点射线追踪是解决复杂地质结构下反射波射线正演的有效方法。在初至波层析射线追踪算法基础上，提出了一种两点射线追踪方法，利用层析网格对模型进行离散化，通过两阶段法射线追踪，分别对激发点和接收点按向前处理过程计算模型单元及节点的旅行时，两次时间相加作为最小旅行时，再在目的层界面邻域扫描最小旅行时子震源网格单元，用粒子群算法在该单元内扫描全局最小旅行时点，得到反射点位置与反射夹角，再利用向后处理过程运用旅行时线性插值算法，从反射点分别到激发点、接收点反向追踪射线路径，最后得到反射波两点射线路径。     

Framing distance: local vs. non-local news in Hong Kong press

Geographical location as a “natural” attribute of news has always been a source of news manipulation. This research investigates how different community newspapers select, interpret, and package events originating in places of varying distances. Contextualized in Hong Kong, three media frames (authority, conflict, and attribution) are closely examined and theoretically connected to three types of newspapers (mass appeal, elite, and pro-establishment) across four locales (local, mainland China, Asian, and international). To test the hypotheses, a large-scale content analysis of 14 daily newspapers in Hong Kong was conducted. On the whole, findings supported the three hypotheses, showing that local news was systematically differentiated from non-local news in terms of the frequency of political authorities cited, presence of diversified opinions, and the likelihood of either individuals or institutions being blamed for social wrongs. Considerable variations were detected across different types of newspapers as well. Theoretical and social implications of the empirical findings are discussed.     

一类抛物型方程的变网格时空有限元改进格式

研究了抛物型方程的有限元算法,通过在有限元格式中引入平衡项,解空间中放弃了满足初始条件的强制条件,得到了改进的变网格时空有限格式,并给出了cG(1)dG(0)格式的后验误差估计.     

适应网格环境的物流网络研究

随着物流网络这一概念的明确,对物流网络运行环境特性与对应发展模式等问题的探索已接踵而至.本文论证了物流网络应与将逐步兴起的网格环境协调发展的合理性,并展开了对物流网络与网格环境协调发展的框架结构、网络服务资源管理等一些关键问题的进一步分析.     

NEAREST NEIGHBOUR ANALYSIS OF UNEQUALLY REPLICATED TRIALS

There has been much work on the use of neighbouring plots to control environmental variation in the analysis of agricultural field experiments. In particular, the Residual Maximum Likelihood Neighbour (REMLN) analysis of Gleeson&Cullis (1987) appears very promising. The application of the REMLN analysis to an unequally replicated field trial augmented with an additional variety planted every six plots in a grid system is here compared with a covariance (COV) analysis using the neighbouring grid or check plot values as the covariate. The results indicate that the REMLN analysis gives more accurate estimates of treatment contrasts than the COV analyses, but that the estimate of treatment means can be biased. The bias depends on the mean of the check plot. This bias can be removed by adjusting the estimates of the treatment means such that their average equals the average of the raw means rather than that of the raw data.     

不可压缩管流的广义有限元方法

本文将广义有限元法用于求解不可压缩管流.通过泛函的变域变分理论推导出严格的网格自适应性条件,可以在给定网格节点数目的条件下,在计算时自动调整网格的分布,使泛函取得极值,同时也使流场参数和网格节点位置取得最优值.对一维喷管的计算结果表明,广义有限元法理论上严密,在计算中是可行的,是常规有限元法向高精度的自适应网格方向的合理推广.     

Estimating mixtures of normal distributions via empirical characteristic function

This paper uses the empirical characteristic function (ECF) procedure to estimate the parameters of mixtures of normal distributions. Since the characteristic function is uniformly bounded, the procedure gives estimates that are numerically stable. It is shown that, using Monte Carlo simulation, the finite sample properties of th ECF estimator are very good, even in the case where the popular maximum likelihood estimator fails to exist. An empirical application is illustrated using the monthl excess return of the Nyse value-weighted index.     

基于网格的数字图书馆分布式资源存储模型分析

基于网格的资源存储采用存储虚拟化、简化存储管理等模式,具有高可用性、可管理性、可扩充性和高安全性等优势。能全面有效地解决数字图书馆的资源存储问题。同时,为了构建数字图书馆分布式资源网格存储应用模型,提出了存储空间管理、元数据目录服务、副本管理、备份管理等功能模块设计。     

基于HyperMesh的活塞网格划分策略研究

网格划分作为有限元数值模拟分析的一个重要环节,它直接影响着后续数值计算求解时间及分析结果的精确性。活塞作为多特征的复杂结构体,其网格划分具有很大的难度。借助于HyperMesh软件强大的CAE建模、网格划分及可视化功能,针对同一活塞几何模型的网格划分和质量检查,对比不同网格条件下模态分析过程和结果的差异,进而阐明了得到高质量活塞网格的处理对策和技巧,为同类型结构的网格划分和最优化分析提供参考。