Determining stress intensity factors of composites using crack opening displacement

The main purpose of this paper is to find the mixed-mode stress intensity factors of composite materials using the crack opening displacement (COD). First, a series solution of the composite material with a crack was used to evaluate COD values. Then, the least-squares method was used to calculate mixed-mode stress intensity factors. This algorithm can be applied to any method that generates or measures COD values. The major advantage of this method is that COD values very near the crack tip are not necessary. Both finite element simulations and laboratory experiments were applied to validate this least-squares method with acceptable accuracy if the even terms of the series solution are removed.     

基于纠错编码和小波变换的数字图像水印算法

文章提出了一种基于小波变换和纠错编码的数字图像水印算法,该算法不需要利用原始图像。实验结果表明,该算法较好地保持了图像的质量,并大大提高了检测的可靠性,对常见的图像处理方法显示了较强的鲁棒性。     

三维数字城市的建设

提出了一种应用三维技术和虚拟现实交互技术来构建三维数字城市的设计思想和实施方案，探讨了具体实现三维数字城市系统而积累的实践经验，介绍了综合运用3DS MAX、AUTOCAD和CULT3D对“实例”进行制作的具体方法和步骤，并给出了部分制作结果。结果表明该系统获得了较好的实时浏览和交互浏览功能，且有良好的视觉效果。     

Ensuring primary realization of pressure unit in the vacuum range without typically utilized static expansion system

After the break-up of Czechoslovakia in 1993 the primary metrological standards authority almost fully remained in Slovakia. So we had to build our primary vacuum metrology anew. But we could do it using uptodate techniques that are more effective and they enable us to fulfil our task more effectively and in a shorter time.The steady demand to widen the lower pressure range and a steady demand for maximal accuracy collide with the financial possibilities open to a small country. So it is impossible to follow the classical pattern for the vacuum standards: liquid columns, static expansion system and dynamic expansion system. But it is possible to utilize contemporary progress in construction of piston manometers. This enables us to discard liquid column and static expansion techniques in favour of piston technique [Tesar J, Prazak D. Vacuum 2002; 67: 311, Tesar J, Prazak D, Krajicek Z. In:Proceedings of international symposium on Pressure and Vacuum, 2003. p. 169, Tesar J, Repa P, Prazak D, Krajicek Z, Peksa L. Vacuum 2004; 76: 491.]. Such system fulfils all the needs of a little industrial country and is economically acceptable.     

An Area Optimization Method for Digital Filter Design

In this paper, we propose an efficient design method for area optimization in a digital filter. The conventional methods to reduce the number of adders in a filter have the problem of a long critical path delay caused by the deep logic depth of the filter due to adder sharing. Furthermore, there is such a disadvantage that they use the transposed direct form (TDF) filter which needs more registers than those of the direct form (DF) filter. In this paper, we present a hybrid structure of a TDF and DF based on the flattened coefficients method so that it can reduce the number of flip‐flops and full‐adders without additional critical path delay. We also propose a resource sharing method and sharing‐pattern searching algorithm to reduce the number of adders without deepening the logic depth. Simulation results show that the proposed structure can save the number of adders and registers by 22 and 26%, respectively, compared to the best one used in the past.     

The topographic normalization of hyperspectral data: implications for the selection of spectral end members and lithologic mapping

Compact Airborne Spectrographic Imager (CASI) hyperspectral data is used to investigate the effects of topography on the selection of spectral end members, and to assess whether the topographic correction improves the discrimination of rock units for lithologic mapping. A publicly available Digital Elevation Model (DEM), at a scale of 1:50,000, is used to model the radiance variation of the scene as a function of topography, assuming a Lambertian surface. Skylight is estimated and removed from the airborne data using a dark object correction. The CASI data is corrected on a pixel-by-pixel basis to normalize the scene to a uniform solar illumination and viewing geometry. The results show that topography has the effect of expanding end member clusters at times resulting in the overlap of clusters and that the correction process can effectively reduce the variation in detected radiance due to changes in local illumination. When topographic effects are embedded in the hyperspectral data, methods typically used for the selection of end members, such as the convex hull method, can miss end members or result in the selection of nonrepresentative pixels as end members. Thus, end members selected by some conventional methods are very likely “incomplete” or “nonrepresentative” if the topographic effect is embedded in the data. As shown in this study, the topographic correction can reveal hidden end members and achieve a better representation of end members via the statistical center of isolated clusters.     

Is construction procurement a key to sustainable development?

Has specialization of professional roles obstructed the holistic approach and sustainable development? A preliminary survey in Botswana involving construction professionals found that existing procurement systems have not integrated the efforts of the different project participants and also fail to fulfil the expectations of the users. A holistic approach involving the re-integration of construction disciplines by applying new procurement methods is proposed. An integrated, holistic way of working could provide a number of synergies through the consideration of the building project as an entire system. The implications include better decision making upstream, more efficient use of resources and the mitigation of negative environmental effects downstream.

La specialisation professionnelle est-elle un obstacle a l'approche globale et au developpement durable? Une etude preliminaire menee au Botswana et portant sur les metiers de la construction a revele que les systemes d'approvisionnement actuels n'integrent pas les efforts des differents participants a un projet et ne repondent pas aux attentes des utilisateurs. Cet article propose une approche globale dont le succes repose sur la reintegration de ces metiers et sur de nouvelles methodes d'approvisionnement. Une methode de travail integree et holistique, ou un projet de construction serait considere comme un systeme complet, pourrait faire naitre un certain nombre de synergies. Cette hypothese exige un meilleur processus decisionnel en amont une utilisation plus efficace des ressources et l'attenuation des effets negatifs sur l'environnement en aval.     

Design and performance of large low-cost solar water heating systems

An analysis is presented for the monthly performance evaluation of a simple design low cost solar water heating systems. A sample of typical results is presented which confirms their suitability as solar heating systems for summer peacking or as solar preheaters for year around loads.     

数字测图,数字制图及勘测设计一体化

简述引用瑞得软件建立数字化成图系统，以进一步实现测量与工程设计一体化，使得繁琐的作业过程变为简单，缩短作业时间，不断提高生产作业效率。     

一种RISC单片机的分块结构寄存器堆

介绍了一种用于ＲＩＳＣ单片机ＰＩＣ１６Ｃ５７的寄存器堆，讨论了为降低功耗所采用的分块结构，详细说明了译码逻辑、ＳＲＡＭ单元、读／写电路和文件选择寄存器等电路的形式及其工作原理