Data envelopment analysis classification machine

This paper establishes the equivalent relationship between the data classification machine and the data envelopment analysis (DEA) model, and thus build up a DEA based classification machine. A data is characterized by a set of values. Without loss of the generality, it is assumed that the data with a set of smaller values is preferred. The classification is to label if a particular data belongs to a specified group according to a set of predetermined characteristic or attribute values. We treat such a data as a decision making unit (DMU) with these given attribute values as input and an artificial output of identical value 1. Then classifying a data is equivalent to testing if the DMU is in the production possibility set, called acceptance domain, constructed by a sample training data set. The proposed DEA classification machine consists of an acceptance domain and a classification function. The acceptance domain is given by an explicit system of linear inequalities. This makes the classification process computationally convenient. We then discuss the preference cone restricted classification process. The method can be applied to classifying large amount of data. Furthermore, the research finds that DEA classification machines based on different DEA models have the same format. Input-oriented and output-oriented DEA classification machines have similar properties. The method developed has great potential in practice with its computational efficiency.     

Bounded Model Checking Using Satisfiability Solving

The phrase model checking refers to algorithms for exploring the state space of a transition system to determine if it obeys a specification of its intended behavior. These algorithms can perform exhaustive verification in a highly automatic manner, and, thus, have attracted much interest in industry. Model checking programs are now being commercially marketed. However, model checking has been held back by the state explosion problem, which is the problem that the number of states in a system grows exponentially in the number of system components. Much research has been devoted to ameliorating this problem.In this tutorial, we first give a brief overview of the history of model checking to date, and then focus on recent techniques that combine model checking with satisfiability solving. These techniques, known as bounded model checking, do a very fast exploration of the state space, and for some types of problems seem to offer large performance improvements over previous approaches. We review experiments with bounded model checking on both public domain and industrial designs, and propose a methodology for applying the technique in industry for invariance checking. We then summarize the pros and cons of this new technology and discuss future research efforts to extend its capabilities.     

液化器异形偏心锥有限元应力分析

以客户提供的液化器设计结构草案和设计载荷为基础进行分析,对液化器下部带夹套的异形偏心锥体结构进行强度核算.首先利用三维建模软件SOLIDWORK建立实体模型,然后将模型导入有限元分析计算软件ANSYS中定义单元、划分网格和施加载荷,再进行有限元内压静载荷分析和外压屈曲稳定性分析,最后依据国家标准JB4732-1995(2005确认)中的相关评定规则对分析结果进行评定.对结构草案中弯曲应力超过标准要求的不连续结构区域进行结构改造,降低弯曲应力,使液化器下部锥体的最终设计方案能够满足国家标准的要求和客户的要求.     

一类奇异分数阶微分方程正解的存在性

研究了一类奇异非线性分数阶微分方程的边值问题.首先给出了该问题的格林函数和其所满足的一些性质,然后利用Krasuoselskii锥上的不动点定理和Leray-Schauder选择定理,建立了该方程至少存在1个正解的充分性条件.     

太阳系行星公转轨道的锥面支架设计研究

依据太阳系行星公转轨道参数将平面曲线扩充成空间曲面,建立异面椭圆变换关系和椭圆锥面方程,分析锥面截线的展开特征,给出锥截面构件的平面加工方法和同顶共焦锥面支架的合成方法。     

渤海底水油田泡沫控水锥技术研究与应用

底水锥进是目前渤海底水油田开发所面临的严峻问题。针对本问题,通过泡沫扫描方法,多孔介质内阻力因子测试、封堵能力评价、提高采收率评价等手段对泡沫生成、稳定性、封堵效果、抗油性等进行了研究。结果表明,泡沫有较好的控水效果,并且确定施工起泡剂质量分数为0．5％,气液体积比为2∶1。该技术在渤海Q HD32-6油田进行了成功应用,实现了良好的控制水锥效果,表明该技术具有良好的应用前景。     

圆锥截线的一致性分析

运用投影柱面对圆锥截线进行分类剖析,解决了圆锥截线及其正投影曲线的系统性和统一性问题。     

探测器倾斜的锥束FDK修正重建算法

在锥束工业CT系统中,通常要求射线源焦点、物体旋转中心、平板探测器中心三点在一条直线上,与平板探测器垂直。由于机械的定位误差,探测器定位后会出现一定角度的倾斜现象,如果直接利用平板探测器倾斜后采集的投影数据进行重建,重建结果将会出现偏离,产生伪影。针对该问题,利用系统标定的方法测得探测器倾斜角度,利用机械校正对其进行粗调,利用提出的基于探测器倾斜的FDK修正算法进行微调,经过两次校正可以有效抑制由于平板探测器倾斜造成的伪影,通过实验验证了该方法的可行性。     

时延丢包网络控制系统的分析与控制

针对网络控制系统中同时存在时延和丢包问题,基于零阶保持器的工作机制,将同时受时延和丢包影响的网络控制系统建模为输入带有时延的控制系统,根据李雅普诺夫稳定性理论和时滞系统理论得出控制系统的时滞相关稳定性条件,进一步基于锥补线性化的方法给出控制器的设计方法,有效解决了网络控制系统中同时存在时延和丢包的控制问题。仿真算例表明所提方法的有效性。     

似椭圆法留设保护煤柱及精度分析

针对目前传统留设保护煤柱的方法存在的问题进行了分析,基于保护地面一点的原理,得出了保护地面一点的公式,进而提出了似椭圆法留设保护煤柱的原理,给出了留设保护煤柱的方法与步骤.实例分析表明,与传统垂直断面法相比,似椭圆法留设保护煤柱可以大大解放“三下”呆滞煤量.依据保护煤柱围护带留设的目的,通过对似椭圆法留设保护煤柱的精度进行分析,确定了似椭圆法留设保护煤柱围护带的宽度,并对其围护带宽度的合理性与适用性进行了探讨.