寻找无效或低效生产层的方法

注水和产液量加大是导致特高含水期油气生产成本上升的主要要素，如何寻找无效或低效生产层、控制无效或低效注水及产液量已成为搞好综合调整、降低油气生产成本的关键问题。因此，从理论分析、实验数据及经验值等方面分析、探讨了以累积注水倍数、数值模拟计算、吸水剖面资料、油井找水资料、注水井分层压力降落速度、精细地质研究等为依据的6种寻找无效或低效生产层的方法，并将其应用于喇嘛甸油田。实践表明，以累积注水倍数为依据，同时结合测井、试井资料，能够比较准确地判断无效或低效生产层。     

媒体同步关系的描述

由于多媒体信息系统中，需要集成各种数据类型，而这些数据类型又有着密切的时间关系，所以对于多媒体来说，同步问题是很重要的，而同步的基础是为同步关系建立一个独立于实现环境的抽象的表示模型，本文着重讨论几种描述媒体同步关系的模型。     

A rule-based approach for robust clump splitting

This paper presents a robust rule-based approach for the splitting of binary clumps that are formed by objects of diverse shapes and sizes. First, the deepest boundary pixels, i.e., the concavity pixels in a clump, are detected using a fast and accurate scheme. Next, concavity-based rules are applied to generate the candidate split lines that join pairs of concavity pixels. A figure of merit is used to determine the best split line from the set of candidate lines. Experimental results show that the proposed approach is robust and accurate.     

汽轮机转子热应力在线计算灰色数学模型

热应力计算中边界条件、物性参数和初始条件等模型输入参数的灰色特性，使得以近似点值为输入得到的计算结果缺乏准确性依据和度量，该文提出的灰色数学模型，用区间数代替近似点值建立灰色数学模型，得出热应力在线计算值的灰色描述，可以更好地符合工程计算需要。文中针对模型应用的复杂程度，以汽轮机转子为对象，对单纯灰边界问题给出了简单的端点计算法及其依据；对复合灰边界灰物性问题建立了差分格式的数学模型，应用区间高斯迭代算法，结合模型结构特点推导了简易的基于内包含不等式的算法，并且给出两种算法的数值算例对比。     

Positive state‐bounding observer for positive interval continuous‐time systems with time delay

This paper is concerned with the problem of positive observer synthesis for positive systems with both interval parameter uncertainties and time delay. Conventional observers may no longer be applicable for such kind of systems due to the positivity constraint on the observers, and they only provide an estimate of the system state in an asymptotic way. A pair of positive observers with state‐bounding feature is proposed to estimate the state of positive systems at all times in this paper. A necessary and sufficient condition for the existence of desired observers is first established, and the observer matrices can be obtained easily through the solutions of a set of linear matrix inequalities (LMIs). Then, to reduce the error signal between the system state and its estimates, an iterative LMI algorithm is developed to compute the optimized state‐bounding observer matrices. Finally, a numerical example is presented to show the effectiveness and applicability of the theoretical results. Copyright © 2011 John Wiley & Sons, Ltd.     

Analysis of nonlinear electrical circuits using bernstein polynomials

In electrical circuit analysis, it is often necessary to find the set of all direct current (d.c.) operating points (either voltages or currents) of nonlinear circuits. In general, these nonlinear equations are often represented as polynomial systems. In this paper, we address the problem of finding the solutions of nonlinear electrical circuits, which are modeled as systems of n polynomial equations contained in an n-dimensional box. Branch and Bound algorithms based on interval methods can give guaranteed enclosures for the solution. However, because of repeated evaluations of the function values, these methods tend to become slower. Branch and Bound algorithm based on Bernstein coefficients can be used to solve the systems of polynomial equations. This avoids the repeated evaluation of function values, but maintains more or less the same number of iterations as that of interval branch and bound methods. We propose an algorithm for obtaining the solution of polynomial systems, which includes a pruning step using Bernstein Krawczyk operator and a Bernstein Coefficient Contraction algorithm to obtain Bernstein coefficients of the new domain. We solved three circuit analysis problems using our proposed algorithm. We compared the performance of our proposed algorithm with INTLAB based solver and found that our proposed algorithm is more efficient and fast.     

一种基于风险传播的信息系统风险评估方法

传统信息系统的风险评估方法未考虑节点的状态变化和风险的传播方向,且评估结果的准确性受专家主观性的影响,对此,提出了一种基于风险传播的信息系统风险评估方法.首先,确定节点的初始状态转移概率矩阵,并根据攻击属性对矩阵进行修正,得到节点状态转移概率;其次,基于系统风险传播网络拓扑图和节点属性值计算节点在各方向的传播概率;然后,利用三参数区间数方法获取节点威胁事件的量化值;最后,根据风险评估方法计算各节点的风险值.实验结果表明,基于风险传播方法的评估流程更客观、合理,可提高信息系统风险评估的整体性和准确性.     

虚拟企业伙伴选择中模糊因素的定量评估

针对虚拟企业伙伴选择时存在不一致区间判断的复杂评估问题,组建战略联盟决策群并确定着眼于候选伙伴实现机遇的互补竞争力评价指标体系,提出在层次分析法(AHP)框架下,运用有下限和上限的区间数表达候选伙伴之间不一致、不确定的比较比例,获得区间比较矩阵,引入模糊集的隶属度函数表示对选择方案的满意程度,构造模糊约束集合,利用线性规划方法求解具有最大满意程度的优先权矢量,计算出候选者的总体优先顺序.结果表明,该方法能够从可行域为空的不一致区间比较矩阵导出模糊优先权矢量.列举的虚拟企业伙伴选择实例验证了应用这个方法从模糊判断矩阵计算出确定的优先权重的有效性,这是其他方法难以做到的.     

基于任务拆分的继电保护云整定计算方法

大电网继电保护的整定计算涉及大量的故障运算与定值配合计算,当前的整定计算软件计算能力有限,难以满足一体化、智能化整定计算的需求,使用云计算成为新一代整定计算软件的重点研究方向。研究了一种基于计算任务拆分的继电保护云整定计算方法,将大规模整定计算任务拆分至最小颗粒,通过任务代理服务器合理分配计算任务、接收回执,调用云服务器计算池进行故障计算,并在辽宁电网省地一体化整定平台上进行了应用。实践结果表明,该方法不但能够保证整定计算结果的准确,而且可以显著提高整定计算的速度。