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151.
康续瀚  周亚军 《山西建筑》2007,33(30):54-55
介绍了法西斯大厦的基本情况,通过对朱赛普·特拉尼的代表作法西斯大厦的空间结构、承重结构、围护结构、立面结构的分析,以使人们更深刻地理解特拉尼的建筑思想,探索其积极的现实意义。  相似文献   
152.
为了回答灯泡贯流泵装置中的灯泡体究竟应该前置还是应该后置的问题,应用水泵装置三维湍流数值模拟的方法分别研究了南水北调东线工程某泵站前置灯泡和后置灯泡贯流泵装置两个不同方案的流态,揭示了前置灯泡和后置灯泡贯流泵装置的基本流动属性;数值模拟的结果得到流道模型试验的验证。研究结果表明:前置灯泡贯流泵装置的进、出水流态均匀平顺,水力损失较小;后置灯泡贯流泵装置的进水流态均匀平顺,但出水流道内存在明显的偏流和旋涡流动,水力损失较大;灯泡体前置符合水力学的基本原理,是获得最佳灯泡贯流泵装置水力性能的必要条件之一。  相似文献   
153.
塔里木盆地是经历了多个原型盆地发育演化的大型叠合盆地,具有多期构造运动,发育多个区域构造不整合面。通过对构造层序和主要构造不整合分布的研究,总体上可以将塔里木盆地划分为5个一级构造层序和13个二级构造层序;主要构造不整合显示出一定的分布特征,大体从隆起区、斜坡区和坳陷区,常由高角度不整合、微角度或平行不整合到整合接触带。高角度不整合带,对油气的分布、运聚成藏起着一定的促进作用和破坏作用。不整合的发育,可以成为油气侧向运移的良好通道;可以为油气提供良好的储集场所和空间;也可以使先期油气藏遭到破坏和封闭重建,发生二次成藏。阐明不整合界面的特征,可以对分析盆地演化、古隆起古地貌恢复提供有利的依据.对油气的运移、聚集、成藏研究有着重要的意义。  相似文献   
154.
An Efficient Code-Based Voxel-Traversing Algorithm   总被引:3,自引:1,他引:2  
The paper considers an efficient approach to traversing a uniformly-subdivided space pierced by a line segment. A voxel, as the basic constituent element of the uniformly subdivided space, is restricted to having the form of a cube. The algorithm works in two steps. In the first step, the so-called Bresenham voxels are identified and, by comparing their position codes, their type of connectivity is determined. To achieve the required connectivity between neighbouring voxels, the second step of the algorithm is applied to find the missing voxels. In this way, the algorithm efficiently switches between face-, edge- and vertex-connectivity. Although the algorithm works with oating-point precision, it is extremely computationally efficient, and tests of speed compared with the Müller, Cleary & Wyvill, Amanatides & Woo, and Zemčik algorithms are described.  相似文献   
155.
现代光学和通讯理论由于引入了傅里叶变换的方法,使计算光学系统和通讯系统的物像的对应关系简洁、清晰。该文用傅氏变换计算长为2a、照度为A的均匀缝光源在观察面上的光强分布为I(x)=│E(x)│^2=AA^2a^2(sin2πfa/2πfa)此方法也可运用于矩形孔、圆孔等。  相似文献   
156.
Automated techniques for satellite imagery navigation and co-location are especially required for environmental monitoring activities intensively using satellite data. In this work are presented the results obtained after 2 years of operational use of the Subpixel Automatic Navigation of AVHRR (SANA) scheme. An automatic method for accuracy assessment of satellite navigation techniques, which permits a preliminary evaluation of their performances, dealing with a large collection of test images is also proposed. The navigation accuracy assessment, performed by using a selection of small islands as reference points, is discussed.Results achieved over more than 400 Advanced Very-High-Resolution Radiometer (AVHRR) scenes confirm that the SANA scheme is a very accurate one (computed mean navigation error is generally about one AVHRR pixel). Furthermore, because of its high processing speed, it can be considered a suitable tool for intensive satellite data processing in multitemporal analyses, especially required for environmental studies as well as for operational monitoring purposes.  相似文献   
157.
In this paper we show that finding solutions of a system of multivariate polynomial equalities and inequalities in the max algebra is equivalent to solving an Extended Linear Complementarity Problem. This allows us to find all solutions of such a system of multivariate polynomial equalities and inequalities and provides a geometrical insight in the structure of the solution set. We also demonstrate that this enables us to solve many important problems in the max algebra and the max-min-plus algebra such as matrix decompositions, construction of matrices with a given characteristic polynomial, state space transformations and the (minimal) state space realization problem.Research assistant with the N.F.W.O. (Belgian National Fund for Scientific Research).Senior research associate with the N.F.W.O.  相似文献   
158.
Justin Zobel  Philip Dart 《Software》1995,25(3):331-345
Approximate string matching is used for spelling correction and personal name matching. In this paper we show how to use string matching techniques in conjunction with lexicon indexes to find approximate matches in a large lexicon. We test several lexicon indexing techniques, including n-grams and permuted lexicons, and several string matching techniques, including string similarity measures and phonetic coding. We propose methods for combining these techniques, and show experimentally that these combinations yield good retrieval effectiveness while keeping index size and retrieval time low. Our experiments also suggest that, in contrast to previous claims, phonetic codings are markedly inferior to string distance measures, which are demonstrated to be suitable for both spelling correction and personal name matching.  相似文献   
159.
The paper describes the colour approximation problem and the method of dynamic palette construction is suggested for its solution. The method uses the graphic display palette based on the computed true colour of the individual picture. Some aspects of human colour perception are considered. Two metrics in colour space are introduced to estimate closeness of the suggested colour approximation. The method was applied to visualize 3D scenes generated by ray tracing.  相似文献   
160.
Recognition of hand drawn shapes is beneficial in drawing packages and automated sketch entry in handheld computers. In this paper, we propose a new approach to on-line geometric shape recognition with incremental training function, which utilizes a heuristic function to reduce noise and a neural network for classification and on-line training. Instead of recognizing segments of a drawing and then performing syntactical analysis to match with a predefined shape, which is weak in terms of generalization and dealing with noise, we examine the shape as a whole. The main concept of the recognition method is derived from the fact that internal angles are very important in the perceived shape of outlines. Our application's aim is to recognize elliptic, rectangular, and triangular shapes in a way similar to human cognition of these shapes. Human beings recognize such basic shapes regardless of the variations in size, noise on the shape border, rotation and in the case of triangles, regardless of the type of the triangle. The key concept is that the neural network learns the relationships between the internal angles of a shape and its classification, therefore only a few training samples which represent the class of the shape are sufficient. Fast meremental training, which is performed on-line, is accomplished by the use of the Binary Synaptic Weights algorithm, a one pass, feedforward neural network training algorithm. Incremental training offers the advantage of adjusting the recognition capability of the system to the user's drawings. the results are very successful, such that the neural network correctly classified shapes that did not have any resemblance to the shapes in the initial training set.  相似文献   
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