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21.
This paper presents a stereo vision system for the detection and distance computation of a preceding vehicle. It is divided in two major steps. Initially, a stereo vision-based algorithm is used to extract relevant three-dimensional (3-D) features in the scene, these features are investigated further in order to select the ones that belong to vertical objects only and not to the road or background. These 3-D vertical features are then used as a starting point for preceding vehicle detection; by using a symmetry operator, a match against a simplified model of a rear vehicle's shape is performed using a monocular vision-based approach that allows the identification of a preceding vehicle. In addition, using the 3-D information previously extracted, an accurate distance computation is performed.  相似文献   
22.
The aim of this study was to evaluate the use of total coliforms (TC) and faecal coliforms (FC) using a membrane filtration method for precise monitoring of faecal pollution in Korean surface water. The samples were collected in Korea from both main rivers and their tributaries. Presumptive TC * FC were enumerated. The ratios of presumptive FC to TC were not constant, but varied widely, and TC were difficult to enumerate because of overgrowth by background colonies. For FC this was not the case. Seven hundred and three purified strains of presumptive TC * FC and their background colonies were biotyped using API 20E. Among 272 presumptive TC, non-faecal related species, Aeromonas hydrophila dominated (34.6%) and E. coli accounted for only 5.1%. In contrast, E. coli made up 89% of the 209 presumptive FC. Furthermore, of 164 background colonies on Endo Agar LES, 54.9% was A. hydrophila, while background colonies on m-FC Agar were few (58 strains), and despite their atypical colony appearance, most of them were biotyped as enteric bacteria. These results reveal that the detection of FC rather than TC using m-FC Agar is more appropriate for faecal pollution monitoring in eutrophicated surface water located in a temperate region.  相似文献   
23.
Energy-based methods for motion estimation in image sequences process the input data either in the spatiotemporal or in the frequency domain. In both cases, the algorithms already described in the literature often require a huge number of elementary operations. In this paper, we describe a class of velocity selective filters which yield an accurate detection of the edges moving in the sequence. We first present a filtering scheme based on a convolution operation computed on a finite size neighborhood and describe its properties in the spatiotemporal and frequency domains. Then, we show that filters with similar properties can be implemented recursively, i.e., as convolutions computed on infinite-size neighborhoods. As an example, we finally show the filters' responses in the case of two superimposed translational motions.  相似文献   
24.
Presents an obituary and information about the life and accomplishments of Josef Maria Bro?ek. Born August 14, 1913, in the ancient town of Melnik, in central Bohemia, today the Czech Republic, Josef spent his childhood in Poland (Warsaw, 1913- 1915) and in Siberia (1915-1920). His education in Czechoslovakia culminated with a thesis on "Memory, Its Measurement and Structure" and a PhD awarded in June 1937. In the history of psychology, his lifetime project bore the title "Historiography of Psychology Around the World," and it covered about 20 geographical areas. Extensive attention was devoted to institutional and organizational developments as journals, academic settings, archives, museums, research groups, conferences, and institutes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
25.
塔里木油田水碳酸盐平衡系数与有机酸的意义   总被引:3,自引:2,他引:1  
李伟  刘宝珺  闵磊 《石油学报》2003,24(5):32-35
根据统计学规律,对塔里木盆地油田水进行了研究,阐明了该盆地油田水的碳酸盐平衡系数(简称为RC)与有机酸的基本特征。从油田水的无机组分与有机组分的统计分析中发现了油田水的碳酸盐平衡系数与有机酸存在明显的负相关性,进一步论证了碳酸盐平衡系数和有机酸与油气聚集及油气性质的关系。碳酸盐平衡系数越低及低碳有机酸的含量越高,它们与油藏,尤其是与 轻质油或气藏的关系越密切。从两者的关系中初步了解到有机酸的溶蚀作用对油气藏中储层次生孔隙的形成应有较重要的影响。  相似文献   
26.
温州市龙湾段标准堤地基土中普遍存在一层海积淤泥,其强度低,压缩性高,承载力低,不能满足标准堤填筑及水闸运行的要求。采用预压法进行地基处理,取得的地基沉降、水平位移、孔隙水压力等现场观测资料,总结分析了该段海积淤泥地基的变形规律和特点。并提供了有关的原型观测数据,其沉降曲线规律性较好。  相似文献   
27.
28.
The bond strengths of polymer concretes containing up to 15% (based on polymer resin) of diacrylate (DA) monomers were examined and compared with those without DA. A change occurring with the addition of DA monomers was an increase in the bond strength of polymer concrete to wet substrates. Zinc diacrylate (ZDA) and calcium diacrylate (CDA) were each used as an additive to monomers and resins [methyl methacrylate (MMA), polyester, and two kinds of epoxies]. The variables were amount of the DA monomers and surface conditions (wet or dry and smooth or rough). Bond strengths were measured by tension bond. ZDA was found to improve the bond strength of MMA and polyester, whereas CDA improved the bond strength of epoxies. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 991–1000, 2003  相似文献   
29.
The expression of cytokeratins (CK), involucrin, vimentin, CD34, and alpha-smooth-muscle actin was studied in fetal and adult hair follicles. The first stage of the developing hair follicle is characterized by palisaded, elongated epithelial cells budding from the epidermal basal layer. These cells express CK5/6, CK14, CK17, CK19, and vimentin. During the following weeks of gestation, different structures in the developing hair follicle can be identified and characterized. The matrical cells display only CK19. The keratinocytes of the outer root sheath express CK5/6, CK14, CK17, CK19, and involucrin; those of the inner root sheath, CK4, CK18, and involucrin; those of the isthmus, the same profile as the ORS. In the infundibulum, the basal-layer keratinocytes express CK5/6, CK14, CK17, and CK19, whereas in the suprabasal layers CK1, CK4, CK10, CK14, and CK17 are seen. The adult hair follicle in anagen fails to express CK19 in the matrical cells and isthmus and both CK17 and CK19 in the infundibulum. These profiles of intermediate filaments and other markers appear to be potentially useful in categorizing neoplasms with apparent follicular differentiation.  相似文献   
30.
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