Three Phase Harmonic Power Flow Using PhaseComponent for Asymmetric Network

With the increasement of the harmonic quantity in power system ,single phase harmonic power flow calculation can't meet the needs. This paper discusses the components model in detail under harmonic condition in three phase distribution power system, include generator,transformer,line and load. Particularly, the transformer model considers the winding connection, the phase shifting among primary and secondary windings, and the off-normal tapping.The three-phase model of transformer, used in traditional harmonic power flow, may the preuent the model from converging, so the paper proposes a three phase back forward sweep harmonic load flow algorithm based on phase-components. At last, a test example was used to prove the algorithm. The results indicate that the proposed method is efficient.     

ON THE SINGULAR CAUCHY PROBLEM

In this paper, a singular Cauchy problem iS studied. The unflat solutions for some singular Cauchy problem are obtained by Adomian's decomposition method.     

基于Vague集的多属性多专家决策购书模型

高校图书馆的职能是为师生提供有效的信息以满足教学、科研的需要。图书馆每年纸质图书的采购是一项重要工作,所采购图书的品质直接影响教辅的成效及馆藏的质量。根据各学院教师对图书的各属性评判信息,引入Vague值的一些运算法则及得分函数,在专家权重给定的条件下,建立基于Vague值加权算术平均算子集结的图书优劣排序模型,为新书采购提供有效的参考信息。     

Stem quality assessment using terrestrial laser scanning technology: a case study of ash trees with a range of defects in two stands in Ireland

Information on stem quality of standing (broadleaf) timber is of great importance to the forestry sector to help optimise harvesting and marketing strategies. Manual assessment of such quality parameters in standing trees is extremely difficult, time consuming and costly. The objectives of this study were therefore to assess stem quality parameters such as taper, lean and sweep in ash (Fraxinus excelsior L.) stands, during leaves-on and leaves-off conditions, using terrestrial laser scanning technology, and to compare the estimated parameters with manually measured values in a mature and young stand. Diameter estimation was more accurate during the leaves-off condition in both stands, resulting in taper estimates that were closer to the manually obtained values as well. However, in general, the taper values did not match those obtained manually very closely. Given that the sample trees were chosen deliberately to include noticeable defects such as non-circularity, bending, swellings, knots resulting from the removal of branches and multiple leaders, this is not surprising. It probably is the case that the scanned data capture these defects more accurately than the manually collected data, especially when multi-scan data are used.     

拖拉机发动机信号降噪与分离处理新方法

介绍了一种处理信号的新方法——模式滤波法,将该方法应用于拖拉机发动机信号的处理中,可实现信号与噪声合理、完整的分离,不仅为有效地去除发动机信号中的噪声奠定了基础,也为拖拉机发动机的故障诊断研究提供了理论参考。     

非线性算子和的值域定理

Ｘ为实Ｂａｎａｃｈ空间,Ｓ、Ｔ为非线性算子。本文讨论了Ｒ（Ｓ＋Ｔ）与Ｒ（Ｓ）＋Ｒ（Ｔ）之间的关系,得到了使Ｓ,Ｔ在较弱的条件下有Ｒ（Ｓ＋Ｔ）＝Ｒ（Ｓ）Ｒ（Ｔ）及ｉｎｔＲ（Ｓ＋Ｔ）＝ｉｎｔ（Ｒ（Ｓ）＋Ｒ（Ｔ））成立的一个定理。     

作物病害图像中重叠病斑分离算法

针对传统的分水岭分割算法的不足,应用了一种基于标记测地重建的分水岭算法对棉花重叠病斑图像进行分离.首先对病斑二值图像利用多尺度距离变换获得病斑的距离图像,通过极限腐蚀操作检测出标记种子;然后以种子标记为基础.运用形态学测地重建运算获取测地影响区骨架SKIZ--分水岭线;最后利用分水岭线与原病斑图像进行交集运算.从而得到分离的图像.运用该算法对棉花重叠病斑图像进行分离,试验结果表明:该方法能较好地将图像中的重叠病斑分离,并较好地保存病斑边缘信息,对图像中的微小结构和噪声不敏感,具有良好的鲁棒性.     

基于人-机系统的水田耕整机安全性研究

针对水田耕整机常发生安全事故的现实,从事故成因、人-机-环境系统运行的有效性和提高安全性措施等方面,运用人机系统理论和方法研究了水田耕整机人机系统中的安全问题.研究表明水田耕整机侧翻事故由人的不安全行为、物的不安全状态和管理失误三方面的因素所引起.把操作者作为系统中的一个环节,利用人的行为知识,提高生产过程与机械的合理性和有效性,并提出了提高水田耕整机安全性的建议.     

厦门海域渔业资源现存量评析

2006-2007年夏季（2006年8月）、冬季（2007年1月）、春季（2007年4月）和秋季（2007年10月）在厦门海域利用底拖网渔船开展渔业资源调查．根据调查资料,对厦门海域（约2713km2）的渔业资源现状进行了评析．研究结果表明,4个季节渔业资源平均密度为981．97ks／km2,其中秋季居首位,约为1261．39ks／km2;冬季和夏季次之,分别为951．31kg/km2和936．93kg／km2,而春季资源密度最低,约为778．24kg/km2．各个季节的资源密度,鱼类均居首位,甲壳类次之,头足类最低．各季节鱼类优势种分别为：春季鱼类优势种有6种,以二长棘鲷（Parargyrops edita）幼鱼和短吻鳐（Leiognathus brevirostris）分别为第一和第二优势种;夏季有7种,以中华海鲶（Arius sinensis）和叫姑鱼（Johnius belengerii）分别为第一和第二优势种;秋季也有7种,以龙头鱼（Harpadon nehereus）、叫姑鱼和中华海鲶为主要优势种;冬季有4种,以叫姑鱼为最主要优势种．4个季节的平均渔业资源现存量约为1694．71t;渔业潜在可捕量约10523t．渔业资源分布与水温、水深及盐度关系较密切．该海域渔业资源已经明显衰退,急需加强渔业资源的管理和保护．