我国水库洪水资源化研究进展

作为洪水资源化的重要非工程性措施,水库洪水资源化能充分利用水库调节作用以实现洪水的灾害属性转变为资源属性。本文在提出水库实现洪水资源化的必备条件的基础上,对目前国内具有代表性的水库洪水资源化方法进行了对比性归纳总结。最后提出了我国水库洪水资源化理论研究和实践应用中存在的问题,为今后研究提供了参考。     

基于二维云模型的数据库安全等级评估研究

针对信息安全等级保护测评中数据库安全等级判定存在模糊性和不完整性,提出了关于二维云模型的数据库安全等级评估方法。通过对数据库和数据自身的测评结果等级进行划分,构造数据库安全等级评估规则;通过云发生器依据每条规则的两组数字特征构建二维云模型的数据库安全等级评估云图,再根据评估云图投影出等级评估的投影面,实现数据库安全等级评估的定量划分。通过实例验证,上述方法简单有效可行,具有一定的应用价值。     

Economic design of time-between-events control chart system

This article presents the economic design of the control chart system consisting of several individual control charts based on time-between-events (TBE) data for monitoring multistage manufacturing processes. The design algorithm considers all the TBE charts within a system in an integrative and optimal manner. Numerical studies show that the proposed design algorithm improves the performance characteristics (in terms of profit) considerably. The proposed control chart system is easy to understand and operate, and thus the floor operators can utilize and understand it as easily as for the traditional system.     

A methodology for joint optimization for maintenance planning, process quality and production scheduling

Performance of a manufacturing system depends significantly on the shop floor performance. Traditionally, shop floor operational policies concerning maintenance scheduling, quality control and production scheduling have been considered and optimized independently. However, these three aspects of operations planning do have an interaction effect on each other and hence need to be considered jointly for improving the system performance. In this paper, a model is developed for joint optimization of these three aspects in a manufacturing system. First, a model has been developed for integrating maintenance scheduling and process quality control policy decisions. It provided an optimal preventive maintenance interval and control chart parameters that minimize expected cost per unit time. Subsequently, the optimal preventive maintenance interval is integrated with the production schedule in order to determine the optimal batch sequence that will minimize penalty-cost incurred due to schedule delay. An example is presented to illustrate the proposed model. It also compares the system performance employing the proposed integrated approach with that obtained by considering maintenance, quality and production scheduling independently. Substantial economic benefits are seen in the joint optimization.     

Mixture control chart patterns recognition using independent component analysis and support vector machine

Effective recognition of control chart patterns (CCPs) is an important issue since abnormal patterns exhibited in control charts can be associated with certain assignable causes which affect the process. Most of the existing studies assume that the observed process data which needs to be recognized are basic types of abnormal CCPs. However, in practical situations, the observed process data could be mixture patterns, which consist of two basic CCPs combined together. In this study, a hybrid scheme using independent component analysis (ICA) and support vector machine (SVM) is proposed for CCPs recognition. The proposed hybrid ICA-SVM scheme initially applies an ICA to the mixture patterns in order to generate independent components (ICs). The hidden basic patterns of the mixture patterns can be discovered in these ICs. The ICs can then serve as the input variables of the SVM for building a CCP recognition model. Experimental results revealed that the proposed scheme is able to effectively recognize mixture control chart patterns and outperform the single SVM models, which did not use an ICA as a preprocessor.     

基于多智能体的备件需求仿真模型?

分析m维修策略在k/N冗余系统的使用特点,提出基于多智能体的备件需求量仿真模型。将工作部件和备件分别用2种Agent表示,即部件(SRU)Agent和备件(SparePart)Agent,并构建各自的状态机模型。采用事件驱动方式控制各个Agent的状态变化,从而间接控制系统的行为。通过算例验证了该方法的适用性。     

一种高速缓存方案的实现方法

基于Altera公司的EP2SGX90FF1508C3N和NEC公司的UPD44165364AF5,提出了一种高速缓存方案。本设计采用可编程逻辑器件,灵活性高,可靠性强,可以根据用户的需要进行方便的扩展和升级。深入研究了QDRII SRAM的工作原理和时序原理,提出了比较可靠的读写状态机实现方案。硬件设计经过实际测试,达到了预期的指标,实现了43.2Gb/s的数据吞吐速率,并且成功用于某产品中。     

On the World Wide Web

ABSTRACT

An analysis of Web citations was performed to examine three aspects of scholarly and research communication: use of authoritative information, use of correct citation style, and availability of the cited sources for the purpose of verification. Results of the study indicate that a database or a repository of Web citations needs to be established.     

改进的组合赋权雷达图在电网电能质量综合评估中的应用

针对传统雷达图的不足,提出一种改进的组合赋权雷达图,并用于电网电能质量综合评估.运用概率与数理统计的分析方法对主、客观赋权方法得到的指标权值分别处理,基于组合权值与原主、客观权值之间的偏差总和最小的优化思想,得到雷达图中各项指标的组合权值.根据组合权值对各指标对应的扇形区域排序并分配扇区大小,用扇形区域的对角线作为指标轴绘制雷达图.评估过程既突出各评估指标的不同重要性,又反映了指标之间的相互作用.通过算例和实际应用验证了组合赋权雷达图评估方法的合理性和在电能质量综合评估中的有效性.     

统计过程控制方法在费托合成中试运转中的应用

统计过程控制是一种采用统计技术对过程数据进行分析和控制的方法,为了提高费托合成过程关键技术指标的稳定性和过程能力,将这一方法应用到了该过程当中。以产油量100 t/a规模的费托合成中试过程为应用场景,对已经完成的试验过程参数进行控制图分析,发现并消除过程中引起参数异常波动的特殊原因。过程参数达到统计受控状态后,过程的关键技术指标稳定性和过程能力都会提高,消除异常波动后的试验结果也更加准确可信。同时,分析获得的过程参数统计受控范围也可以作为相同条件后续试验过程的参数控制限。该方法的应用对于费托中试过程异常波动的发现、消除和过程稳定性、能力的提高具有一定的指导作用。