电子式车速里程表

详细介绍霍尔速度传感器,里程计数脉冲的产生,步进电机的驱动和ＢＬ２１１５集成电路在电子式车速里程表中的应用。     

高功率因数斩波式串级调速系统的研究

为了克服传统串级调速系统功率因数低的缺点 ,提出了一种新型斩波式串级调速方案。该方案中的逆变电压与逆变电流的夹角可以在 15 0°与 180°之间变动 ,有效地提高了串级调速系统的功率因数     

过程企业供应链管理监控系统的研究

结合过程企业的特点 ,采用先进的网络技术和软件开发技术 ,开展了供应链管理监控系统研究 ,提出了适合过程企业的供应链监控系统结构框架 ,并在企业供应链系统网络环境下进行了开发应用研究。     

发动机进口流场温度畸变测试技术研究

进口流场的温度畸变对军用飞机发动机稳定性具有比压力畸变更大的影响。文本采用研制的ＤＡＰ－ＩＤ３型高型高速大容量数据采集及实时存储处理系统,对温度畸变试验及温度畸变模拟装置调试、评价中的一些测量技术问题进行了研究,在现场获得成功的试验结果。并对影响精度的一些因素进行了分析,提出了一些有益建议。     

供应链管理系统中应用安全框架的设计与实现

该论文分析了供应链管理系统的结构和用户特征,提出了对此系统应用安全框架要求:管理的方便性、数据的机密性和数据的完整性。然后从类关系图的角度总体设计了此应用框架,在传统RBAC模型中角色的基础上增加关联角色的概念,使得RBAC模型更加灵活,另外还进行角色的可扩展性设计和数据的保密设计,并实现了系统的功能。最后通过集团公司的试用结果来证实了设计的可行性。     

多模型分层切换车速控制

针对汽车纵向动力学建模存在较大不确定性的问题,设计了一种多模型分层切换车速控制系统。在不同汽车参数和工况下,辨识得到节气门开度到车速的传递函数,并建立不确定模型集合对其进行描述基础上,应用鲁棒控制理论对监督器和鲁棒控制器集合进行设计,实现了多模型分层切换车速控制。实验结果表明,与自适应控制器相比,设计的控制器对参数变化具有更快的调节能力,实现了更加快速准确的控制。     

A dynamic bibliometric model for identifying online communities

Predictive modelling of online dynamic user-interaction recordings and community identification from such data becomes more and more important with the widespread use of online communication technologies. Despite of the time-dependent nature of the problem, existing approaches of community identification are based on static or fully observed network connections. Here we present a new, dynamic generative model for the inference of communities from a sequence of temporal events produced through online computer- mediated interactions. The distinctive feature of our approach is that it tries to model the process in a more realistic manner, including an account for possible random temporal delays between the intended connections. The inference of these delays from the data then forms an integral part of our state-clustering methodology, so that the most likely communities are found on the basis of the likely intended connections rather than just the observed ones. We derive a maximum likelihood estimation algorithm for the identification of our model, which turns out to be computationally efficient for the analysis of historical data and it scales linearly with the number of non-zero observed (L + 1)-grams, where L is the Markov memory length. In addition, we also derive an incremental version of the algorithm, which could be used for real-time analysis. Results obtained on both synthetic and real-world data sets demonstrate the approach is flexible and able to reveal novel and insightful structural aspects of online interactions. In particular, the analysis of a full day worth synchronous Internet relay chat participation sequence, reveals the formation of an extremely clear community structure.     

Clustered Chain Path Index for XML Document: Efficiently Processing Branch Queries

Branch query processing is a core operation of XML query processing. In recent years, a number of stack based twig join algorithms have been proposed to process twig queries based on tag stream index. However, in tag stream index, each element is labeled separately without considering the similarity among elements. Besides, algorithms based on tag stream index perform inefficiently on large document. This paper proposes a novel index, named Clustered Chain Path Index, based on a novel labeling scheme. This index provides efficient support for processing branch queries. It also has the same cardinality as 1-index against tree structured XML document. Based on CCPI, efficient algorithms, KMP-Match-Path and Related-Path-Segment-Join, are proposed to process queries efficiently. Analysis and experimental results show that proposed query processing algorithms based on CCPI outperform other algorithms and have good scalability. This paper is partially supported by Natural Science Foundation of Heilongjiang Province, Grant No. zjg03-05 and National Natural Science Foundation of China, Grant No. 60473075 and Key Program of the National Natural Science Foundation of China, Grant No. 60533110.     

Relative importance,specific investment and ownership in interorganizational systems

Implementation and maintenance of interorganizational systems (IOS) require investments by all the participating firms. Compared with intraorganizational systems, however, there are additional uncertainties and risks. This is because the benefits of IOS investment depend not only on a firm’s own decisions, but also on those of its business partners. Without appropriate levels of investment by all the firms participating in an IOS, they cannot reap the full benefits. Drawing upon the literature in institutional economics, we examine IOS ownership as a means to induce value-maximizing noncontractible investments. We model the impact of two factors derived from the theory of incomplete contracts and transaction cost economics: relative importance of investments and specificity of investments. We apply the model to a vendor-managed inventory system (VMI) in a supply chain setting. We show that when the specificity of investments is high, this is a more critical determinant of optimal ownership structure than the relative importance of investments. As technologies used in IOS become increasingly redeployable and reusable, and less specific, the relative importance of investments becomes a dominant factor. We also show that the bargaining mechanism—or the agreed upon approach to splitting the incremental payoffs—that is used affects the relationship between these factors in determining the optimal ownership structure of an IOS.

Mutual authentication protocols for RFID systems

With the availability of low-cost radio frequency identification (RFID) tags, security becomes an increasing concern.However, such tags do not permit complex eryptographic functions due to their computational, communications, and storage limitations.In this paper, we investigate the security issues and requirements of RFID systems, and propose ultra-light weight and light weight protocols for low-cost RFID tags. The proposed protocols has been applied to a supply chain management system.