基于AOP的Web Services管理架构研究

WebServices技术通过集成第三方Web服务，可以极大提高企业级应用系统的开发效率。但是目前的大多数分布式应用中，客户端应用只能简单集成WebServices，无法根据实际需求的变化动态管理WebServices。本文讨论了几种不同的WebServices管理架构，进一步给出了一种基于面向方面的编程技术AOP的Web Services动态管理架构。采用这种架构，我们在客户端应用与Web Services之间引入管理层，并且在管理层采用动态横切技术实现对Web Services的管理。     

Effect of building length on wind loads on low-rise buildings with a steep roof pitch

A wind tunnel model study was carried out on long, low-rise buildings with a steep roof pitch to determine the effect of the length-to-span aspect ratio on the external wind pressure distributions. The study showed a significant increase in the magnitude of the negative pressure coefficients on the leeward roof and wall, with an increase in aspect ratio, for oblique approach winds. These large suction pressures also generate large design wind load effects on the frames near the gable-end. The 1989 edition of the Australian standard for wind loads, AS 1170.2-1989 was found to underestimate the wind loads on steep pitch gable-roof buildings of aspect ratio greater than 3, on areas near the windward gable-end, and hence the critical bending moments in the supporting structural frames. The current Australian/New Zealand wind load standard, AS/NZS 1170.2-2002 specifies increased negative pressure coefficients on the leeward half of high pitch roof buildings, and critical bending moments in the supporting frames calculated from these distributions agree quite well with values obtained from the wind tunnel study. However, other major standards severely underestimate the critical bending moments, and the effective pressure coefficients producing those bending moments, especially on the leeward roof slope.     

低环径比设计概念——一种可接受的核聚变动力系统

低环径比（ＬＡＲ）概念作为一种聚变动力堆设计方案,它的许多关键问题已用总体设计程序进行了评估计算。Ａ＝１．４,κ＝３,βＴ＝６２％和自持电流为８７％的平衡设计的物理基础取自过去已得到的结果。计算表明,若引入氪（Ｋｒ）以便增加等离子体芯部辐射,则可将偏滤器上的热流部分地转移到第一壁上,但此时芯部的聚变功率也有所减少。设计中采用了积极的工艺措施,将关键部件的参数推向设计极限,为了减小堆尺寸,对铜合金的环向磁场（ＴＦ）线圈中心柱未施屏蔽。本文提出了一项能承受高的热负荷和中子壁负载的堆设计,它在第一壁和包层中用氦作载热剂、钒合金作结构材料、锂作氚增殖剂。若采用上述材料组合和设计,一个电功率为１９６６ＭＷｅ的聚变动力堆的尺寸,可减小到大半径为３．０５ｍ。设铜合金和钒合金的辐照寿命为１５ＭＷｙ／ｍ２,考虑到在堆的３０年寿期内,须更换铜合金中心柱和外侧第一壁以及包层,估计电价为５．１９美分／千瓦时,而总的直接投资为４８．８亿美元。这说明采用本ＬＡＲ设计,聚变电厂的造价（２４８２美元／千瓦电）开始接近可接受的价格水平,为了获取经济的聚变动力,采用ＬＡＲ发展途径可能是明智之举。     

Effect of nanoplatelet aspect ratio on mechanical properties of epoxy nanocomposites

To study the effect of the aspect ratio of nanoplatelets on the mechanical properties of polymer nanocomposites, epoxy/α-zirconium phosphate nanocomposites with two distinctive aspect ratios at ca. 100 and 1000 have been prepared and characterized. Scanning electron microscopy and transmission electron microscopy were utilized to confirm the two different sizes and aspect ratios of nanoplatelets in epoxy. As expected, it is found that mechanical properties of the nanocomposite are affected by the aspect ratio of nanoplatelets in epoxy. That is, a higher aspect ratio renders a better improvement in modulus. It is also found that the interfacial characteristics between the nanoplatelets and polymer matrix are most critical in affecting the strength and ductility of the polymer. The operative fracture mechanisms depend strongly on the aspect ratio of the nanoplatelets incorporated. The crack deflection mechanism, which leads to a tortuous path crack growth, is only observed for the high aspect ratio system. The implication of the present findings for structural applications of polymer nanocomposites is discussed.     

Stress–strain curves for steel-fiber reinforced concrete under compression

Steel-fiber reinforced concrete is increasingly being used day by day as a structural material. The complete stress–strain curve of the material in compression is needed for the analysis and design of structures. In this experimental investigation, an attempt has been made to generate the complete stress–strain curve experimentally for steel-fiber reinforced concrete for compressive strength ranging from 30 to 50 MPa. Round crimped fibers with three volume fractions of 0.5%, 0.75% and 1.0% (39, 59, and 78 kg/m³) and for two aspect ratios of 55 and 82 are considered. The effect of fiber addition to concrete on some of the major parameters namely peak stress, strain at peak stress, the toughness of concrete and the nature of the stress–strain curve is studied. A simple analytical model is proposed to generate both the ascending and descending portions of the stress–strain curve. There exists a good correlation between the experimental results and those calculated based on the analytical model. Equations are also proposed to quantify the effect of fiber on compressive strength, strain at peak stress and the toughness of concrete in terms of fiber reinforcing parameter.     

三维物体的形态图表达方法

三维物体的表达方法是计算机视觉中的关键问题之一，现有的各种三维物体表达方法虽然在各自的识别中得到应用，但都存在各自的局限性，用形态图表达三维物体是一种以视点为中心的表达方法，由于它列举了一个物体所有可能的“定性”形象，即它可使用最少的二维投影线图（特征视图）来表达一个完整的三维物体，因此使三维物体识别转化为2D与2D的匹配，该文首先定义了二维线图拓扑结构等价的判别准则，然后给出了构造透明物体形态图的方法，最后根据拓扑结构等价准则来得到不透明物体的形态图和特征图，并用圆锥与圆柱相交的实例进行了验证。     

基于AOP的软件测试框架设计

通过研究AOP (Aspect Oriented Programming) 这种新兴发展中的技术,提出一种基于AOP的软件测试框架,适用于在对复杂的JAVA应用做回归测试和动态白盒测试,将需要测试的测试用例以测试方面的形式注册到容器,由容器统一将测试方面定义的测试建议织入到各动态测试连接点.     

基于.NET平台的面向方面编程语言Eos

目前面向方面编程(AOP)的主流工具是基于Java平台的AspectJ。该文论述了基于.NET平台的新AOP技术——Eos语言,该语言扩展了C#语言,引入一套完整的AOP语法,并提供Eos专用编译器,使其性能高于其他AOP实现技术。支持多语言的.NET平台的应用使跨语言应用AOP成为可能。