An Efficient Output-Size Sensitive Parallel Algorithm for Hidden-Surface Removal for Terrains

We describe an efficient parallel algorithm for hidden-surface removal for terrain maps. The algorithm runs in O(log ⁴ n) steps on the CREW PRAM model with a work bound of O((n+k) \polylog ( n)) where n and k are the input and output sizes, respectively. In order to achieve the work bound we use a number of techniques, among which our use of persistent data structures is somewhat novel in the context of parallel algorithms. Received July 29, 1998; revised October 5, 1999.     

Elimination of Boolean variables for probabilistic coherence

 In this paper we deal with the computational complexity problem of checking the coherence of a partial probability assessment (called CPA). The CPA problem, like its analogous PSAT, is NP-complete so we look for an heuristic procedure to make tractable reasonable instances of the problem. Starting from the characteristic feature of de Finetti's approach (i.e. the explicit distinction between the probabilistic assessment and the logical relations among the sentences) we introduce several rules for a sequential “elimination” of Boolean variables from the domain of the assessment. The procedure resembles the well-known Davis-Putnam rules for the satisfiability, however we have, as a drawback, the introduction of constraints (among real variables) whose satisfiability must be checked. In simple examples we test the efficiency of the procedure respect to the “traditional” approach of solving a linear system with a huge coefficient matrix built from the atoms generated by the domain of the assessment.     

Whatever happened to neurosis? An overview.

Discusses the decision to eliminate the term "neurosis" from the DSM-III. The history of the term is traced; weaknesses of DSM-II pertaining to neurosis are presented; theoretical and political processes in the deletion procedure are described; and an overview is given of the current resolution as presented in DSM-III. Instead of neurosis, "neurotic disorder" and "neurotic process" were distinguished to reduce potential theoretical bias. The process may or may not be seen by the clinician as causal in the disorder, but those of all theoretical persuasions should be able to agree on what the disorder is. (13 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

淮南煤矿采煤沉陷区蓄洪除涝初探

目前我国对于煤矿采煤沉陷区的治理途径仅限于土地的复垦、深挖浅垫、开发湿地等手段,而利用沉陷区做蓄水区,发挥其蓄洪除涝作用的研究案例目前国内比较少见。本文针对淮南矿区的3个主要沉陷区进行了初步分析,摸清了沉陷区的动态变化规律,并预测出未来这些沉陷区的可蓄容积能够极大地缓解当地乃至淮河流域洪涝灾害的压力,同时可以充分利用雨洪资源提高供水保证率,对该地区的防洪除涝及水资源配置具有重大意义。     

Elimination of the computational broadcast in systolic arrays: an application to the qr decomposition algorithm

Two types of broadcast in algorithms are determined: (1) a data broadcast, where one data value is used for more than one computation and (2) a computational broadcast where one variable is computed in more then one computation. Both types of broadcast are preferred to be eliminated when a processor array implementation is desired by using VLSI technology.

When the algorithm computes only one variable value for each index vector then the computational broadcast can be eliminated in a straight forward manner by introducing counter values resulting in a single assignment code. However in cases when the algorithm computes two or more variable values that are specified by a different computational broadcast, has not been considered. As far as is known it has been solved by deriving localized algorithms in single assignment code heuristically.

In this paper we define this problem in terms of a system of affine recurrence equations and analyze the data dependencies introduced. Then we show a synthesis procedure that eliminates the computational broadcast and a few examples of implementation are shown. The QR decomposition algorithm is also presented in a localized single assignment code by using the proposed method and several different parallel implementations are discussed.     

并行化水体表面动态多分辨率物理仿真模型

大面积水体仿真中的细节捕捉较为困难,且渲染效率容易受限。为此,提出一种基于图形处理单元(GPU)的水体表面动态多分辨率物理仿真模型。采用细节层次渐进网格划分方法对水体表面进行建模,利用统一计算构架和GPU技术加速纳维-斯托克斯方程的求解。实验结果表明,随着初始网格分辨率的提高,该模型的加速比逐渐加大,在分辨率达到1 024×1 024的情况下,能保证30帧左右的渲染 效率。     

基于混合高斯模型与码本算法的前景目标检测

提出一种基于混合高斯模型(GMM)与码本算法的前景目标检测方法。利用GMM进行背景图像建模并初步提取前景对象,对背景图像进行码本学习,将码本建模得到的前景对象与GMM得到的前景对象相融合,根据前后2次帧间差分得到前景对象的比例关系,自适应地更新高斯参数和扩展码字,得到前景对象目标。实验结果表明,该方法实时性好,可消除视频序列中的阴影和鬼影,提取完整的前景对象。     

聚合物/无机纳米复合材料热点述评

介绍了纳米技术的发展概况，评述了这一领域的研究现状和发展趋势，并以纳米粘土复合材料为重点综述了聚合物/无机纳米复合材料的力学性能，以及阻隔、杀菌除臭、消烟阻燃等功能。     

大型空分设备气体放空的噪声控制与治理

文章简介了空分设备气体放空时产生的噪声对周围环境的污染和伤害,并对放空气体噪声的控制与治理进行了分析对比;提出大型空分设备,特别是内压缩流程的空分设备,大流量低、中、高压气体放空,应采用消声塔集中排放,有效控制和治理气体放空噪声。     

数字拍摄中噪波的产生与消除

数字拍摄中所产生的噪波会影响质量。本文讨论了数字拍摄中噪波产生的原因，并针对性地提出了如何消除或减弱噪波的方法。