A new representation of orientable 2-manifold polygonal surfaces for geometric modelling

INTRODUCTION Polygonal surface has become ubiquitous due to its efficient representation of highly detailed geomet- ric objects with arbitrary topological type. In real-world simulation and analysis, a 3D physical object is modelled as a closed subset in ú3 bounded by a connected, compact and orientable 2D manifold. For algorithmically describing orientable 2-manifold polygonal surfaces, the practical data structure should not only easily check manifold property and topo- logical consist…     

Discrimination of geons by pigeons: The effects of variations in surface depiction

We explored how changes in the depiction of the surface features of a simple volume (a geon) affected the pigeon’s recognition performance. Pigeons were trained to make a different keypeck response to each of four computer-rendered single-geon objects. In Experiment 1, the pigeons were tested with images of the original stimuli in which the light source was shifted from its original position, as well as with silhouettes and line drawings of these objects. All three types of stimulus variations resulted in marked drops in performance: above chance for silhouettes and light-change stimuli, but at chance for line drawings. In Experiment 2, the pigeons were tested with images of the original stimuli in which the contrast levels were either increased or decreased. These transformations resulted in very small drops in performance (except for the complete absence of contrast-a silhouette). These results indicated that the pigeons attended to the shape of the outside contour of an object and to the relative brightness of an object’s surface contours.     

Visible region extraction from a sequence of rational Bézier surfaces

A method for computing the visible regions of free-form surfaces is proposed in this paper. Our work is focused on accurately calculating the visible regions of the sequenced rational Bézier surfaces forming a solid model and having coincident edges but no inner-intersection among them. The proposed method calculates the silhouettes of the surfaces without tessellating them into triangle meshes commonly used in previous methods so that arbitrary precision can be obtained. The computed silhouettes of visible surfaces are projected onto a plane orthogonal to the parallel light. Then their spatial relationship is applied to calculate the boundaries of mutual-occlusion regions. As the connectivity of the surfaces on the solid model is taken into account, a surface clustering technique is also employed and the mutual-occlusion calculation is accelerated. Experimental results showed that our method is efficient and robust, and can also handle complex shapes with arbitrary precision. Project supported by the National Basic Research Program (973) of China (No. 2002CB312106) and the National Natural Science Foundation of China (Nos. 60533070, and 60403047). The third author was supported by the project sponsored by a Foundation for the Author of National Excellent Doctoral Dissertation of China (No. 200342) and a Program for New Century Excellent Talents in University (No. NCET-04-0088), China     

Automatic recognition of intersecting features of freeform sheet metal parts

This paper presents an approach for recognizing both isolated and intersecting geometric features of freeform surface models of parts, for the purpose of automating the process planning of sheet metal forming. The developed methodology has three major steps： subdivision of B-spline surfaces, detection of protrusions and depressions, and recognition of geometric features for sheet metal forming domain. The input geometry data format of the part is based on an IGES CAD surface model represented in the form of trimmed B-spline surfaces. Each surface is classified or subdivided into different curvature regions with the aid of curvature property surfaces obtained by using symbolic computation of B-spline surfaces. Those regions satisfying a particular geometry and topology relation are recognized as protrusion and depression （DP） shapes. The DP shapes are then classified into different geometric features using a rule-based approach. A verified feasibility study of the developed method is also presented.     

对古塔变形趋势的若干思考

通过建立数学模型来分析古塔的总体变形状况,就是为了科学地对古塔变形趋势有所预测,能有效地采取措施对古塔进行维护。文章采用均值法确定古塔各层中心位置;通过大量的分析假设,运用MATLAB软件结合曲线拟合的最小二乘法,对所测数据进行多项式拟合,列出各层中心点所在曲线的参数方程,求得曲线的曲率和挠率,分析古塔的弯曲、扭曲情况;根据离散的数据图形,比较直观地预测它的变形趋势,有的放矢地采取维护方法。     

Curvature detail representation of triangular surfaces

INTRODUCTION With the favorites of finer and vivid 3D models in visual reality, games and entertainment community, researchers among academic institutions and indus- trial organizations construct detail-rich models by 3D scanning tools and geometry modelling. These mod- els usually contain millions of triangles and occupy hundreds and thousands of MB memories which give great difficulties for editing or operating onto them. A good representation of details makes these operations much eas…     

民族儿童文学在发挥优势中前行

民族儿童文学创作2008年中总体上并无大的变化,但新的优势明显,主要表现为：1．深入到民族文化发展的新层面,使题材优势发挥到极致,使儿童文学民族性得到更充分呈现;2．民族作家的创作视野愈加广阔,从新的时代高度来关注城里的民族儿童;3．表现手段有突破性进展,更加注重和顺应了儿童的心理特征;4．亲情主题上更多地显示出对民族传统美德的承扬、对民族纯朴家风的颂扬;5．及时关注社会问题。     

Relative Heights of Males and Females in Children's Drawings Taille Relative des Silhouettes Masculines et Fe´minines dans les Dessins d'Enfants Alturas Relativas de las Figuras Masculina y Femenina en los Dibujos de los Niños

Two studies are reported concerning the height of male and female figures in children's drawings. In Study 1, 5 and 7 year olds were asked to draw a man and a lady or a boy and a girl. Adult figures were drawn taller than child figures. For boys, the mean heights of their male and female figures were approximately the same but girls drew their females taller than their male figures. The reason for this was that more girls than boys used different structures (incorporating a skirt or trousers into the drawing) to differentiate their figures; this use of different structures results in a taller drawing of a skirted figure. This finding was replicated in Study 2 in which 7-year-olds were asked to draw a lady in a skirt and another in pyjamas: the skirted figure was taller when it had a different structure from the figure in pyjamas, whereas the mean heights of both figures were approximately the same height when the same structure had been used. Deux travaux de recherche ont étudié la taille des silhouettes masculines et féminines dans les dessins d'enfants. Dans l'étude 1, des enfants de 5 et 7 ans ont dû dessiner un homme et une femme ou un garçon et une fille. Les silhouettes adultes ont été dessinées plus grandes que les silhouettes d'enfants. Les garçons ont dessiné des silhouettes d'hommes et de femmes à peu près de la même taille en moyenne, mais les filles ont dessiné leurs femmes plus grandes que leurs hommes. La raison en est que plus de filles que de garçons utilisaient des structures différentes (en incorporant une jupe ou un pantalon dans le dessin) pour différencier leurs silhouettes; cette utilisation de structures différentes résulte en un dessin plus haut de la silhouette en jupe. Ces résultats se retrouvent dans l'étude 2, où des enfants de 7 ans ont dû dessiner une dame en jupe et une autre en pyjama: la silhouette en jupe était plus haute quand elle avait une structure différente de celle en pyjama, tandis que la hauteur moyenne des deux silhouettes était à peu près la même quand la même structure était utilisée. Se informa de dos estudios relacionados con la altura de las figuras masculina y femenina en los dibujos de los niños. En el Estudio 1, se pidió a niños de 5 y 7 años que dibujan un hombre y una mujer, o un chico y una chica. Las figuras adultas fueron dibujadas con una altura mayor que las figuras de niños. Para los niños, las alturas medias de sus figuras masculinas y femeninas fueron aproximadamente las mismas, pero las niñas dibujaron sus figuras femeninas más altas que las masculinas. La razón para esto fue que más niñas que niños usaron estructuras diferentes (incorporando una falda o pantalones en el dibujo) para diferenciar sus figuras. El uso de estas estructuras diferentes resulta en un dibujo más alto de una figura con falda. Este hallazgo se reprodujo en el Estudio 2, en el que se pidió a niños de 7 años que dibujaran una señora con una falda y otra con un pijama: la figura con falda fue más alta cuando tuvo una estructura diferente a la de la figura con pijama, mientras que las alturas medias de ambas figuras fueron aproximadamente la misma altura cuando la hizo uso de la misma estructura.     

叙述视角与文学翻译——《远大前程》及其中译本个案研究

在文学翻译中,叙述视角承载着作品匠心独运的艺术与修辞魅力。译者在文学翻译中由于忽视叙述视角特点而引起"假象等值"问题,从而形成了译文与原作在艺术效果上的鸿沟。所以,在翻译之前,译者有必要对原作的话语层特色进行深入的分析,进入叙述者的视角之中,体味语言形式与作品主题意义的关系,再现原作的美学价值。     

Surface reconstruction by offset surface filtering

The problem of computing a piecewise linear approximation to a surface from its sample has been a focus of research in geometry modeling and graphics due to its widespread applications in computer aided design. In this paper, we give a new algorithm, to be called offset surface filtering (OSF) algorithm, which computes a piecewise-linear approximation of a smooth surface from a finite set of cloud points. The algorithm has two main stages. First, the surface normal on every point is estimated by the least squares best fitting plane method. Second, we construct a restricted Delaunay triangulation, which is a tubular neighborhood of the surface defined by two offset surfaces. The algorithm is simple and robust. We describe an implementation of it and show example outputs.     

基于光纤光栅传感的智能内窥镜形状感知系统

Thisdissertationaimsatprovidingsteadysensingfor theshapedetectionofcolonoscopes.Theresearch especiallydealswiththekeytechniquesoffiberbragg grating(FBG)largecurvaturesensorandsensornet,integratesthetechniquesofmechatronicsandcomput ergraphics,anddevelopsrealtimeFBGshapesensing systemandincrementalshapesensingsystemfor colonoscopies.Aftertheanalysisofstate of the artforthedevelop mentoftheendoscopeandthedifficultiesofcolonos copy,theactualitiesofbothendoscopicshapesensing systemsandofFBGstru…     

论王蒙意识流小说的艺术真实性

王蒙的意识流小说是生活的产物，本从艺术真实性这个角度对其艺术价值进行了探讨，力图从一个新的角度重新审视王蒙的意识流小说。     

论《寂静的房子》的内聚焦叙事

《寂静的房子》出版于1983年,是奥尔罕.帕慕克的第二部小说作品。小说创作在传统的内聚焦叙事上有所创新。既采用了多个角色均以第一人称视角切入叙事盲点,突破叙事限知的方式,又运用多种技术手法点明频繁变换的第一人称所指,引领读者阅读,显得颇为＂超现代化＂。是作家创作由现实主义向现代主义转换的一部重要阶段性作品。     

实现大学生思想政治教育的五大转变

新的形势要求大学生思想政治教育树立新的观念。从理论和实践相结合的角度看,大学生思想政治教育有五个转变:在价值取向上,从狭隘视野到重新审视大学生思想政治教育的转变;在工作重点上,从重视理论建树到面向大学生生活实际的转变;在目的上,从"知之"到大学生"笃行"的转变;在体制和机制上,从简单工作到建立健全互动开放工作系统的转变;在成效上,从短期效应到注重实效性和可持续性的转变。在这个过程中,要加强理论的探讨和工作推进的互动作用。     

论邓小平辩证唯物主义的历史观

邓小平理论中蕴含着丰富的辩证唯物主义的历史观的内容。科学的历史观成为邓小平制定党的路线、方针、政策的重要依据，成为他显示高超的领导才华的基础。本文探讨了邓小平历史观的主要特点，包括邓小平高度重视历史经验的理性认识及其实践因素；邓小平坚持实事求是的精神，以唯物主义和辩证的观点，客观、公正、全面地分析历史上的重大事件及重要人物；邓小平从社会的基本矛盾运动、历史发展的实践活动两个方面，着重又从生产力发展角度来研究发展历史、开辟未来问题，使马克思的研究历史的方法更加具体化、民族化；以及邓小平对创造性发展历史的理论创见和实际贡献。邓小平的这些有关历史的真知灼见，不但启发我们如何正确认识历史、指导我们创造性地发展历史，而且也是对各种形形色色的唯心主义、形而上学的历史观的有力否定。     

文化诗学批判与批评生长

用现实、批判的眼光来看待文化诗学和整个批评环境，可以初步理清它在方法论意义、传播、预设方面的迷误，发现当前批评及文化诗学的异化、浅生状态、异质资源与创作隔膜等诸种弊端，最终形成文化诗学与批评生长的互动关系。     

用旋转法解平面几何题

讲述了用运动、动态的观点来解初中平面几何题，它可以将一个图形沿着某一点旋转一个角度以后，使较复杂的问题简单化，体现了一种几何变换的数学思想，从而达到简捷明快的解题目的。     

数字图像修复关键技术的研究与实现

图像修复尤其是数字图像修复是近几年的研究热点,其目的在于通过填补一些裂缝来使画面恢复原貌,图像修复现已成为计算机图形学和计算机视觉中的一个研究热点,在文物保护、影视特技制作、虚拟现实、多余物体剔除等方面有着重要的应用价值。下文从不同的图像修复方法入手详细研究经典图像修复算法的优缺点,并提出改进措施。     

Work or Play in the Kindergarten?

All over the world there is searching discussion about how much structure is appropriate for children between the ages of 3 and 6. Many teachers still turn to the books of Susan Isaacs (1930, 1933) which give an exciting vision of how children's minds grow during play. Isaacs also describes the role of the nurturing adult who explores the world with children but never dominates or imposes her own view. Several decades later came the work of Marianne Parry (1975) whose contribution includes the distinction between two levels of play; ‘that which educates’, and ‘that which fills time’.     

国内纳丁·戈迪默研究述评与展望

20世纪80年代以来,我国的纳丁.戈迪默研究取得了一定进展,但在研究数量与质量、批评内容与视角、研究的本土意识和独创精神等方面还存在许多问题。研究戈迪默对于辨证地看待全球化和本土化,使中国更好地参与世界性话语并破除"文化霸权"具有重要意义。