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基于运动对象局部场景截取的碰撞检测算法
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作者 康勇 熊岳山 +1 位作者 谭柯 郭光友 《计算机仿真》 CSCD 2008年第11期214-217,共4页
为了解决虚拟心脏介入手术系统中的碰撞检测问题,提出了一种基于运动对象局部场景截取的碰撞检测算法。通过实时构建运动对象的局部场景截取体,可以获取该对象周围的局部场景数据,有效地降低了碰撞检测复杂性。并且它对虚拟场景中对象... 为了解决虚拟心脏介入手术系统中的碰撞检测问题,提出了一种基于运动对象局部场景截取的碰撞检测算法。通过实时构建运动对象的局部场景截取体,可以获取该对象周围的局部场景数据,有效地降低了碰撞检测复杂性。并且它对虚拟场景中对象的形变属性没有特殊要求,可适用于虚拟环境中包含可形变对象的情形。通过虚拟心脏介入手术中的碰撞检测实验表明,碰撞检测频率达到500Hz以上,并能精确给出碰撞点和发生碰撞的基本几何元素等碰撞信息,可以满足虚拟心脏介入手术对碰撞检测的实时性与精确性要求。 展开更多
关键词 碰撞检测 局部场景截取 包围盒 虚拟心脏介入手术
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时态、时制理论与汉语时间参照 被引量:52
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作者 顾阳 《语言科学》 2007年第4期22-38,共17页
由于汉语有相对丰富的时态标记,而缺乏显性的时制标记,很多学者在对汉语句子中的时间进行诠释时,往往将时态或体作为依据。从汉语句子能否成句这个问题着手,文章的考察表明,汉语的场景体中有无"定点"对句子的成句性有决定意... 由于汉语有相对丰富的时态标记,而缺乏显性的时制标记,很多学者在对汉语句子中的时间进行诠释时,往往将时态或体作为依据。从汉语句子能否成句这个问题着手,文章的考察表明,汉语的场景体中有无"定点"对句子的成句性有决定意义。含缺少"定点"的场景体,必须要借助其他功能成分方能成句。含有"定点"的场景体的句子,其定点必须在句中明确表示出来,才能成句,否则亦需要借助其他功能成分方能成句。文章将所罗列的现象归纳为句子的固有成分,并探讨如何将这一系列的句法固有成分统一分析为‘指涉’这一语法功能,即时空上的参照点。一个句子为何要有这样的参照成分?自然语言的名词通过功能化以后,用来指涉实体,那么句子就是动词及其论元通过功能化以后,用来指涉事件或状态。时制通过时空上的参照点来调节和确定说话时间和事件时间的顺序,从而将某个场景(事件或状态)在时空中定位,使说话者可指涉该事件或状态,所以文章尤其关注对句子中参照点的确认,尝试如何确定其在时空定点上的功能。通过演绎,文章证明这些成分都与建立在时空上的参照点并与指涉事件有关,从而推断汉语的句子中具有时制中心语,它支配句子的构建。 展开更多
关键词 时制 时态 场景体 参照时间 级差
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Suitable Region for Flue-cured Tobacco (Nicotiana glauca L.) Planting Based on Spatial Scene Similarity
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作者 董钧祥 郭旦怀 邵小东 《Agricultural Science & Technology》 CAS 2012年第9期1947-1949,1981,共4页
[Objective] The aim was to establish a model based on spatial scene similarity, for which soil, slope, transport, water conservancy, light, social economic factors in suitable planting areas were all considered. A new... [Objective] The aim was to establish a model based on spatial scene similarity, for which soil, slope, transport, water conservancy, light, social economic factors in suitable planting areas were all considered. A new suitable planting area of flue-cured tobacco was determined by comparison and analysis, with consideration of excellent area. [Method] Totaling thirty natural factors were chosen, which were clas- sified into nine categories, from Longpeng Town (LP) and Shaochong Town (SC) in Shiping County in Honghe Hani and Yi Autonomous Prefecture. [Result] According to weights, the factors from high to low were as follows: soil〉light〉elevation〉slope〉 water conservancy〉transport〉baking facility〉planting plans over the years〉others. The similarity of geographical conditions in the area was 0.894 3, which indicated that the planting conditions in the two regions are similar. If farmer population in unit area, farmland quantity for individual farmer, labors in every household, activity in planting flue-cured tobacco and work of local instructor were considered, the weights of different factors were as follows: farmer population in unit area〉farmland quantity for individual farmer〉farmers' activity in planting flue-cured tobacco〉educational back- ground〉labor force in every household〉instructor〉population of farmers' children at- tending school. The similarity of geographical conditions was 0.703 1, which indicated that it is none-natural factors that influence yield and quality of flue-cured tobacco. [Conclusion] According to analysis on suitable planting area of flue-cured tobacco based on assessment of spatial scene similarity, similarity of growing conditions in two spatial scenes can be analyzed and evaluated, which would promote further exploration on, influencing factors and effects on tobacco production. 展开更多
关键词 Similarity of spatial scene Planting of flue-cured tobacco Suitable region
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A new approach to quantifying vehicle induced turbulence for complex traffic scenarios 被引量:3
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作者 Yesul Kim Li Huang +1 位作者 Sunling Gong Charles Q.Jia 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2016年第1期71-78,共8页
Traffic-related pollutants adversely affect air quality, especially in regions near major roadways. The vehicleinduced turbulence(VIT) is a significant factor that controls the initial dilution, dispersion, and ultima... Traffic-related pollutants adversely affect air quality, especially in regions near major roadways. The vehicleinduced turbulence(VIT) is a significant factor that controls the initial dilution, dispersion, and ultimately the chemical and physical fate of pollutants by altering the conditions in the microenvironment. This study used a computational fluid dynamics(CFD) software FLUENT to model the vehicle-induced turbulence(VIT) generated on roadways, with a focus on impact of vehicle-vehicle interactions, traffic density and vehicle composition on turbulent kinetic energy(TKE). We show, for the first time, that the overall TKE from multiple vehicles traveling in series can be estimated by superimposing the TKE of each vehicle, without considering the distance between them while the distance is greater than one vehicle length. This finding is particularly significant since it enables a new approach to VIT simulations where the overall TKE is calculated as a function of number of vehicles. We found that the interactions between vehicles traveling next to each other in adjacent lanes are insignificant,regardless the directions of the traffic flow. Consequently, simulations of different traffic scenarios can be substantially simplified by treating two-way traffic as one-way traffic, with less than 5% difference in the overall volume-averaged TKE. We also developed equations that allow the estimation of the overall volume-averaged TKE as a function of the number and the type of vehicles. 展开更多
关键词 Computational fluid dynamics Turbulent kinetic energy Vehicle-induced turbulence Road-induced turbulence Mixed traffic
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Iconography of National Mourning in Polish Press
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作者 Magdalena Mateja 《Journalism and Mass Communication》 2012年第11期1063-1072,共10页
By the law, the highest-ranking state officials announce national mouming in response to death of prominent persons. The concept of mourning should be understood both as way of showing grief in public spaces and a per... By the law, the highest-ranking state officials announce national mouming in response to death of prominent persons. The concept of mourning should be understood both as way of showing grief in public spaces and a period of time. In turn, the concept of iconography means a collection of illustrations, paintings, prints, drawings relating to a person, place or topic. President of Poland, his wife and other 94 people died in the Smolensk plane crash on April 10, 2010, thus the images of plane crash and its outcome published in different segments of Polish press are the subject of the article. Research based on methods such as interpretation of composition and semiotics. I started my analysis with a few hypotheses: (1) The cultural background, especially religious, determines the mourning visual representation; (2) The result of certain style of visualization can be constructing of a political myth; (3) Different means can be used by mass media in adapting culture patterns process; (4) Different photographic genres can be used to illustrate the mourning; and (5) Press segments differ in way/style of mourning visualization. 展开更多
关键词 national mourning journalistic photography photographic genres Smolensk plane crash presidentLech Kaczynski visualization magazines
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A practical framework for scenario-based optimal decision-making on water-deficient river ecological restoration in mining areas
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作者 Sen YU Ming-Yu WANG 《Journal of Coal Science & Engineering(China)》 2013年第4期566-572,共7页
Mining activities may cause serious damages to the river ecological environment in mining areas. It has been realized that challenging is faced for optimal decision-making on the river ecological restoration resulting... Mining activities may cause serious damages to the river ecological environment in mining areas. It has been realized that challenging is faced for optimal decision-making on the river ecological restoration resulting from system complexity, multi-objectives, long term restoration in which multiple stages may be needed to take, and difficulty in detailed process quan- tification. By analyzing and fully reflecting the differences between the central zone and surrounding zones of the restored river passing through the mining area, the comprehensive evaluation index systems of the central zone and surrounding zones are separately suggested firstly. Then a scenario-based optimization decision-making model for river ecological restoration in min- ing areas was established with taking advantages of spatial divisions and following procedure of first going through optimiza- tion by sub-region level, then optimizing by integration. Then, a framework for scenario-based optimal decision-making on water-deficient river ecological restoration in mining areas is proposed in which a multi-objective and multi-stage spatial division optimization method is considered to improve decision-making efficiency and enhance its practicability. It is indicated that this optimization framework is reasonable and practical, which is expected to offer reliable decision support in identifying the effective solutions on optimal management of the water-deficient river ecological restoration in mining areas. At the same time, it has implications in general land reclamation and ecological restoration in the mining areas. 展开更多
关键词 river ecological restoration optimization model scenario analysis
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Bayesian moving object detection in dynamic scenes using an adaptive foreground model 被引量:1
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作者 Sheng-yang YU Fang-lin WANG +1 位作者 Yun-feng XUE Jie YANG 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2009年第12期1750-1758,共9页
Accurate detection of moving objects is an important step in stable tracking or recognition. By using a nonparametric density estimation method over a joint domain-range representation of image pixels, the correlation... Accurate detection of moving objects is an important step in stable tracking or recognition. By using a nonparametric density estimation method over a joint domain-range representation of image pixels, the correlation between neighboring pixels can be used to achieve high levels of detection accuracy in the presence of dynamic background. However, color similarity between foreground and background will cause many foreground pixels to be misclassified. In this paper, an adaptive foreground model is exploited to detect moving objects in dynamic scenes. The foreground model provides an effective description of foreground by adaptively combining the temporal persistence and spatial coherence of moving objects. Building on the advantages of MAP-MRF (the maximum a posteriori in the Markov random field) decision framework, the proposed method performs well in addressing the challenging problem of missed detection caused by similarity in color between foreground and background pixels. Experimental results on real dynamic scenes show that the proposed method is robust and efficient. 展开更多
关键词 Moving object detection Foreground model Kernel density estimation (KDE) MAP-MRF estimation
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