Sweeping Points

Given a set of points in the plane, and a sweep-line as a tool, what is best way to move the points to a target point using a sequence of sweeps? In a sweep, the sweep-line is placed at a start position somewhere in the plane, then moved orthogonally and continuously to another parallel end position, and then lifted from the plane. The cost of a sequence of sweeps is the total length of the sweeps. Another parameter of interest is the number of sweeps. Four variants are discussed, depending on whether the target is a hole or a pile, and whether the target is specified or freely selected by the algorithm. Here we present a ratio 4/π≈1.27 approximation algorithm in the length measure, which performs at most four sweeps. We also prove that, for the two constrained variants, there are sets of n points for which any sequence of minimum cost requires 3n/2?O(1) sweeps.     

医院超声图象管理系统的设计与实现

介绍了医院超声图象管理系统的功能和特点,并阐述了其关键技术。     

一种简化的人体步行神经网络模型

本文针对复杂的人体步行的神经 -肌肉 -骨胳系统模型 ,分析了步行中的主要关系 ,对神经网络模型作了较大的简化和修改 ,提出了一个简单的神经网络模型 .该模型在步行状态、神经耦合、感觉信号反馈等方面都作了简化 .计算机仿真表明 ,该模型能产生稳定的步行运动     

上海地铁列车控制总线系统的研究

对上海市地铁列车中的三种不同车型的微机控制系统的总线进行分析与研究,并针对近年总线通信中出现的问题,提出改进方法。     

用于高速列车移动网络的资源分配实时算法

误码率高、频繁中断的高速列车移动场景宜采用多宿主容迟网络。但其资源分配计算复杂,实时性较差。基于效用差分法设计初始化过程资源分配算法,以保证过程中每一步的效用单调不减,算法时间复杂度降至O(n)。     

A method for observing the three-dimensional morphologies of inclusions in steel

A method for observing the three-dimensional morphologies of inclusions by deeply eroding a steel sample with a kind of organic solution composed of bromine water,acetone,and HC1 (volume ratio,45∶45∶10...     

Robust partial pole assignment problem for high order control systems

In this paper, we consider the partial pole assignment problem (PPAP) for high order control systems. It is shown that solving the PPAP is essentially solving a pole assignment for a linear system of a much lower order, and the robust PPAP is then concerning the robust pole assignment problem for this linear system. Based on this theory, a rather simple algorithm for solving the robust PPAP is proposed, and numerical examples show that this algorithm does lead to comparable results with earlier algorithms, but at much lower computational cost.     

Performance of Sewage Sludge Treatment and Electricity Generation by Different Configuration Microbial Fuel Cells

This paper compared the degradation efficiency of sludge organic matters and electric-production by two typical microbial fuel cells——dual-chamber microbial fuel cell(DMFC)and single chamber air cathode microbial fuel cell(SAMFC),and the variations of sludge protein,polysaccharide and ammonia nitrogen within the systems were also investigated.The results showed that the concentration of sludge soluble chemical oxygen demand,protein and carbohydrate of DMFC are higher than these of SAMFC during the systems operation,while DMFC can achieve a better ammonia nitrogen removal than SAMFC.Under the same operation condition,the stable voltage output of DMFC and SAMFC is 0.61 V and 0.37 V;the maximum power density of DMFC and SAMFC is 2.79 W/m3and 1.25 W/m3;TCOD removal efficiency of DMFC and SAMFC is 34.14%and 28.63%for 12 d,respectively.Meanwhile,DMFC has a higher coulomb efficiency than SAMFC,but both are less than5%.The results showed that DMFC present a better performance on sludge degradation and electric-production.     

The oxidation state of sulfur detected in Na2O-CaO-SiO2 float glass by X-ray absorption near edge structure spectra

The oxidation state of sulfur is detected in Na2O-CaO-SiO2 float glass by synchrotron radiation X-ray absorption near edge structure (XANES) spectra at the sulfur K edge. The measured spectra show the only presence of S6+ in the Na2O-CaO-SiO2 float glass and the oxidation state of sulfur do not change with the increase of glass depth. It is also found that, after the melt has gone through the molten tin bath, the S6+ is the dominant species, but S2- is also present on both surfaces. It is not certain whether cation bonds to S2- or not, because there are many cations dissolved in the melted tin which makes the spectrum complicated.     

VAc／MMA半连续乳液共聚合的研究：Ⅰ种子乳液共聚合

以过硫酸铵为引发剂，十二烷基硫酸钠为乳化剂，于７０℃下进行了ＶＡｃ＝ＭＭＡ种子乳液共聚合。试验考察了组分和操作条件对体系稳定性，聚合速度及组成分布等的影响，同时，从理论上给出了加料速率与体系稳定性因子间的关系。