Evaluation of a parallel branch-and-bound algorithm on a class ofmultiprocessors

We propose and evaluate a parallel “decomposite best-first” search branch-and-bound algorithm (dbs) for MIN-based multiprocessor systems. We start with a new probabilistic model to estimate the number of evaluated nodes for a serial best-first search branch-and-bound algorithm. This analysis is used in predicting the parallel algorithm speed-up. The proposed algorithm initially decomposes a problem into N subproblems, where N is the number of processors available in a multiprocessor. Afterwards, each processor executes the serial best-first search to find a local feasible solution. Local solutions are broadcasted through the network to compute the final solution. A conflict-free mapping scheme, known as the step-by-step spread, is used for subproblem distribution on the MIN. A speedup expression for the parallel algorithm is then derived using the serial best-first search node evaluation model. Our analysis considers both computation and communication overheads for providing realistic speed-up. Communication modeling is also extended for the parallel global best-first search technique. All the analytical results are validated via simulation. For large systems, when communication overhead is taken into consideration, it is observed that the parallel decomposite best-first search algorithm provides better speed-up compared to other reported schemes     

以网格曲线为连续条件的光滑曲面

本文提出一种以网格边界曲线定义曲面的方法。曲面的计算式唯一地由网格的四条边界线的参数而定，各网格间连接的光滑度完全由网格间的边界线的光滑度来决定。当网格间的边界线具有Ｃ~１连续以上的光滑度时，网络曲面间将自动保证是Ｃ~１连续的，否则将是Ｃ~０连续。利用这个方法，可以方便地从线框模型（ｗｉｒｅ－ｆｒａｍｅｍｏｄｅｌ）建立面模型（ｓｕｒｆａｃｅｍｏｄｅｌ）。     

实体造型中的几何约束

实体造型是一个基于约束的过程，完成从功能约束到几何约束、再到代数约束的转化而得到实体模型。本文讨论了几何约束的层次性及其表示，并且对几何约束同设计意图的关系进行了研究，提出了基于ＣＳＧ／ＧＣＧ／Ｂ－ｒｅｐ的模型表示。     

一种自动布线方法：多级线探索法

本文介绍了一种在微机上实现的印制板自动布线方法──多级线探索法及其编程方法。这种方法是基于完备布线算法的概念，通过分析李氏算法和传统线探索法的不足之处而得到的。虽然它也是一种线探索法，但有较传统线探索法更强的探索能力，不需要结合李氏算法而能单独完成布线任务，是一种较理想的算法，通过实验获得了较为满意的效果。     

强度反射型光纤温度传感器

本文提出并研究了一种新型的强度反射型光纤温度传感器.根据定容气体温度与压力的线性关系,通过简单的测温元调制光纤中的反射光强,从而得知待测温度.这种传感器结构紧凑,造价低廉.在30~50℃范围内,灵敏度可以达到30mV/℃以上.     

Fuzzy controller design by using neural network techniques

This paper investigates the relationship between the piecewise linear fuzzy controller (PLFC), in which the membership functions for fuzzy variables and the associated inference rules are all in piecewise linear forms, and a Gaussian potential function network based controller (GPFNC), in which the network output is a weighted summation of hidden responses from a series of Gaussian potential function units (GPFU's). Systematic procedures are proposed for transformation from a PLFC to its GPFNC counterpart, and vice versa. Based on these transformation principles, a series of systematic and feasible steps is presented for the design of an optimized PLFC (PLFC*) by using neural network techniques. In the design procedures, the simplified PLFC is used as the initial controller structure, then a GPFNC, which gives the approximate control response to the initially given PLFC, is found for further optimization. A neutralization process is used to demonstrate the feasibility and the potential applicability of these intelligent controllers on the regulation of highly nonlinear chemical processes     

无机高分子絮凝剂聚硫酸铁合成条件的研究

实验研究了以工业硫酸亚铁及废硫酸为原料,分别采用NaClo_3、KClO_3、H_2O_2及(o_2+NaNO_2)为氧化剂成聚硫酸铁的条件。在以(O_2+NaNO_2)为氧化剂的合成过程中,发现添加微量助催化剂(型号为HG-1、HG-2和HG-3),对提高合成速度及反应过程的稳定性具有重大作用。     

A hyperplastic anterior choroidal artery with double persistent anastomotic channels

We describe a case of a hyperplastic anterior choroidal artery (AChA) with double persistent anastomotic channels. This hyperplastic AChA, which was detected at vertebral angiography, is different from previously reported cases, because it has an unusual, secondary anastomotic channel.     

在经典极限下量子斯特林制冷机的优化

经济利润率是评价一个实际热力装置的主要指标之一。将有限时间热力学，非平衡量子统计理论和yong经济学相结合，导出了量子斯特林制冷机的最大利润率以及对应的性能界限，其结果与实际斯特林制冷机的优化设计和模型评估提供了一个最佳的预选方案。     

压差式漏率测试仪的实验研究

将薄膜电容真空计的测量室接于被测密闭容器，静态真空室接于一个比较容器，即组成一台压差式漏率测试仪。首先使两容器压力平衡，真空计读数为零。当被测容器存在漏孔时，真空计薄膜两侧形成压差，真空计指示读数，继而计算出该容器的漏率。应用商品真空计在抽真空测试时，检测的最小可测漏率达10－4～10-5Pa·L／s；而在充压测试时，因受气体温度变化的影响，灵敏度会降低几个量级。该仪器有可能具备寻找漏孔位置和确定漏孔漏率的功能。