Combination of sources of evidence with different discounting factors based on a new dissimilarity measure

The sources of evidence may have different reliability and importance in real applications for decision making. The estimation of the discounting (weighting) factors when the prior knowledge is unknown have been regularly studied until recently. In the past, the determination of the weighting factors focused only on reliability discounting rule and it was mainly dependent on the dissimilarity measure between basic belief assignments (bba's) represented by an evidential distance. Nevertheless, it is very difficult to characterize efficiently the dissimilarity only through an evidential distance. Thus, both a distance and a conflict coefficient based on probabilistic transformations BetP are proposed to characterize the dissimilarity. The distance represents the difference between bba's, whereas the conflict coefficient reveals the divergence degree of the hypotheses that two belief functions strongly support. These two aspects of dissimilarity are complementary in a certain sense, and their fusion is used as the dissimilarity measure. Then, a new estimation method of weighting factors is presented by using the proposed dissimilarity measure. In the evaluation of weight of a source, both its dissimilarity with other sources and their weighting factors are considered. The weighting factors can be applied in the both importance and reliability discounting rules, but the selection of the adapted discounting rule should depend on the actual application. Simple numerical examples are given to illustrate the interest of the proposed approach.     

QoS enhancements for global replication management in peer to peer networks

Replica Management is a key issue to reduce the bandwidth consumption, to improve data availability and to maintain data consistency in large distributed systems. Global Replica Management (GRM) means to maintain the data consistency across the entire network. It is preferable particularly for multi-group distributed systems. On the other hand, GRM is not favorable for many applications because a very large number of message passes is needed for replica management processes. In this paper, in order to reduce the number of message passes needed to achieve the efficient GRM strategy, an interconnection structure called the Distributed Spanning Tree (DST) has been employed. The application of DST converts the peer network into logical layered structures and thereby provides a hierarchical mechanism for replication management. It is proved that this hierarchical approach improves the data availability and consistency across the entire network. In addition to these, it is also proved that the proposed approach reduces the data latency and the required number of message passes for any specific application in the network.     

基于不完全信息动态博弈的入侵检测模型

基于风险决策的思想提出了一种全新的入侵检测模型，在不完全信息动态博弈分析的基础上研究入侵检测和入侵响应．把信息安全员与可疑用户节点作为非合作博弈的对立方，从博弈局中人的相互依赖的行动选择角度建立动态响应的博弈模型．通过引入DST方法用于模型中不确定性推理．实现了动态的行为空间与类型空间的概率映射问题．     

电子压力计保护装置的研制和试验

高温高压井的射孔-测试联作中,易损坏昂贵的井下电子压力计。针对井下实际情况,研制了一种新的井下电子压力计的保护装置,其具有良好减震性能,并能降低射孔瞬间突然增压对压力计探头的冲击作用。该装置经过现场试验,效果良好。     

电动汽车动力电池测试系统的变流及控制

动力电池的动态性能直接影响电动汽车的起动、加速、续航、快速充电等指标。分析动力电池的测试要求和方法,选择结合实际路况的变功率测试,使用动态应力测试DST(dynamic stress test)标准功率曲线作参考曲线。模拟工况下电池测试设备要求,选用交错并联双向DC/DC变换器为拓扑结构,详尽阐述了变换器的工作原理,给出了参数设计和控制方法。采用TMS320F28335为控制核心,搭建了硬件实验平台进行测试。实验结果表明,所采用的控制方法能实现交错并联双向DC/DC变换器的快速响应,实现能量的双向流动,满足电动汽车动力电池测试的应用要求。     

Stimgun外套式复合射孔器在塔里木QL-×井的应用

Stimgun是一种外套式复合射孔器,2004年10月首次在中国陆上油田塔里木QL-×井实现了复合射孔与测试联作.施工前,通过计算机分别计算出施工设计所需的射孔枪弹数据、压裂药量、裂缝长度等参数.介绍了QL-×井实施Stimgun工艺技术的作业管柱设计、施工方法及施工效果.该工艺技术可有效地控制裂缝高度,达到消除地层污染而又不出水的效果,对污染严重的地层和低渗透率地层具有较好的改造作用,增产效果明显.     

解决冲突证据的两级组合方法

针对DS理论(DST)中Dempster组合规则在处理高冲突证据时的不足,提出一种解决冲突证据的两级组合方法。该方法将高冲突和低冲突区别对待,在第一级组合中采用基于DSm理论(DSmT)的PCR6规则,化解可能的高冲突证据;在第二级组合中采用Dempster规则,保证良好的收敛速度和计算性能,从而合理、有效地处理各种程度的冲突证据。通过算例分析验证了该方法的有效性。     

塔河油田深井裸眼中途测试技术

中途测试是快速发现油气层的重要手段,塔河奥陶系缝洞型碳酸盐岩油藏是以裸眼完井为主要完井方式,经过多年的探索、实践,塔河油田在测试方式、测试管串、测试压差、测试制度、人工助排、试井解释等方面形成了一套适合塔河奥陶系油藏长裸眼、深井、高温特点的中途测试方法。文章对这套技术作了简要介绍。     

MFE测试工艺在浅层井的应用

通过解决P-T封隔器的坐封负荷、MFE测试器的延时、开关井时“自由点”的控制等问 题,克服了MFE测试器在浅层井测试中存在的局限性,并经实测应用成功,为浅层测试积累了丰 富的经验。     

DST测试在勘探阶段油气藏早期评价中的作用

油气藏早期评价工作在勘探中是十分重要的。综合利用一口井的地层测试和试井解释成果,可以获得多项油气层参数和油气藏边界、含油面积、地质储量及驱动类型等油气藏参数,从而全面评价油气藏,结合动态资料,对油气层目前压力、油气藏产能及动态进行预测,提高勘探资料的利用率。本文结合渤海的9口井实例,进行了探讨。