A dynamic integration algorithm to model surfaces from multiple range views

This paper presents a dynamic integration algorithm to triangulate a surface from multiple range views. This integration technique is based on the reparameterization of the canonic subsets of the Venn diagram of the set of range views. We compute a model based onN views from a model based onN–1 views by processing only the surface segments visible in theN ^th view. An experimental result shows that the proposed integration algorithm can process complex multipart objects containing holes.     

Incremental maintenance of aggregate and outerjoin expressions

Views stored in a data warehouse need to be kept current. As recomputing the views is very expensive, incremental maintenance algorithms are required. Over recent years, several incremental maintenance algorithms have been proposed. None of the proposed algorithms handle the general case of relational expressions involving aggregate and outerjoin operators efficiently.     

Do the Kallikaks look "menacing" or "retarded?"

To extend R. E. Fancher's (see record 1987-31600-001) review of claims that photographs of the Kallikak family in H. H. Goddard's (1912) study had been retouched to make them look more menacing and retarded, 29 Ss (aged 18–69 yrs) were surveyed for their impressions of the photographs. Overall, Ss were strongly inclined to view the photographed individuals as "kind" and "very bright." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

More on Goddard and the Kallikak family photographs.

Discusses retouching of the Kallikak family photographs in H. H. Goddard's (1912) study of mental retardation and heredity, with reference to analyses by R. E. Fancher (see record 1987-31600-001) and S. J. Gould (1981), and concurs with Fancher that the retouching was probably not done for deceitful purposes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Incremental join view maintenance on distributed log-structured storage

Modern database systems desperate for the ability to support highly scalable transactions and efficient queries simultaneously for real-time applications. One solution is to utilize query optimization techniques on the on-line transaction processing (OLTP) systems. The materialized view is considered as a panacea to decrease query latency. However, it also involves the significant cost of maintenance which trades away transaction performance. In this paper, we examine the design space and conclude several design features for the implementation of a view on a distributed log-structured merge-tree (LSMtree), which is a well-known structure for improving data write performance. As a result, we develop two incremental view maintenance (IVM) approaches on LSM-tree. One avoids join computation in view maintenance transactions. Another with two optimizations is proposed to decouple the view maintenance with the transaction process. Under the asynchronous update, we also provide consistency queries for views. Experiments on TPC-H benchmark show our methods achieve better performance than straightforward methods on different workloads.     

张謇职业教育环境观之比较

在兴办实业教育的过程中,张謇投资基础设施,建设实习实训环境;融合中西文化,塑造学习文化环境;规划城市建设,改善校园外部环境.与杜威、黄炎培相比,张謇的职业教育环境观与他们的观点存在着相似之处,但作为实践者和拓荒者,张謇从朴素的救国救民思想出发,率先进行了实业教育的物质环境、文化环境和外部环境的建设,反映了他对环境在人才培养中作用的重视,也体现了他环境育人的价值追求.     

一种虚拟环境下的Rootkit检测与处理技术

rootkit对系统的危害十分严重,其极强的隐蔽性为检测带来了很大的困难。当前对rootkit的检测方法中存在一些不足,并且缺少对检测到rootkit后的定位与处理。针对现有检测方法中的不足,提出了一种虚拟环境下基于虚拟机监控器(Virtual Machine Monitor,VMM)的rootkit检测与处理技术,并在Xen上实现了原型系统rDetector。使用以安全链表为基础的多视图同步谎言检测机制检测rootkit的隐藏性,以内核敏感信息完整性检查检测rootkit对系统的攻击,并利用VMM提供了对rootkit的定位与处理。实验表明,rDetecor对rootkit的检测效果良好,能够迅速准确的检测出rootkit对系统的攻击,并能有效地对rootkit进行处理,对系统造成的性能损失在可接受的范围内。     

Independence of Containing Patterns Property and Its Application in Tree Pattern Query Rewriting Using Views

We show that several classes of tree patterns observe the independence of containing patterns property, that is, if a pattern is contained in the union of several patterns, then it is contained in one of them. We apply this property to two related problems on tree pattern rewriting using views. First, given view V and query Q, is it possible for Q to have an equivalent rewriting using V which is the union of two or more tree patterns, but not an equivalent rewriting which is a single pattern? This problem is of both theoretical and practical importance because, if the answer is no, then, to find an equivalent rewriting of a tree pattern using a view, we should use more efficient methods, such as the polynomial time algorithm of Xu and Özsoyoglu (2005), rather than try to find the union of all contained rewritings (which takes exponential time in the worst case) and test its equivalence to Q. Second, given a set S of views, we want to know under what conditions a subset S′ of S is redundant in the sense that for any query Q, the contained rewritings of Q using the views in S′ are contained in those using the views in S???S′. Solving this problem can help us to, for example, choose the minimum number of views to be cached, or better design the virtual schema in a mediated data integration system, or avoid repeated calculation in query optimization. For the first problem, we identify several classes of tree patterns for which the equivalent rewriting can be expressed as a single tree pattern. For the second problem, we present necessary and sufficient conditions for S′ to be redundant with respect to some classes of tree patterns. For both problems we consider extension to cases where there are rewritings using the intersection of multiple views and/or where a schema graph is present.     

由正交图像造型三维个性化虚拟人体模型

基于正、侧、背面4幅正交人体图像,变形模板人体模型后得到带服饰纹理的个性化虚拟人．以截面环为基本几何元素,给出了模板人体模型的生成和变形方法,建立了截面环和三维人体骨架之间的内在关联;自动提取图像上的人体特征点,生成二维图像上的人体骨架;由三维人体骨架和二维图像上人体骨架之间的对应关系,建立截面环和人体图像之间的对应关系;从人体图像上获取截面环的形状参数,通过参数化变形截面环得到个性化的虚拟人体模型．与已有方法相比,该方法建立在基于特征的参数化框架之上,变形更容易控制,消除了三维模型和二维图像之间对应的不确定性,避免了人体变形中的自交现象,效率高、真实感效果较好．