基于粗糙集的焦炉加热工序控制规则提取

应用粗糙集(RS)理论对焦炉直行温度的控制规则进行了提取。首先收集人工成功控制直行温度的原始样本,添加可控与不可控参数,得到初始决策表;指出模糊控制方法因输入参数过少,从而会导致不确定性决策;然后利用RS理论对初始决策表进行约简,发现了关键影响因素及潜在规律,最终得到两组仅含有三个参数,简洁、一致、完备的控制规则,并经实际运行检验了规则的适用性。     

一种基于点集拓扑分形变幻的云计算登录认证方法

考虑到云服务登录安全性及便捷性的需求,针对单点登录认证模式,提出云计算的统一登录认证方法,并采用点集拓扑分形变幻方法生成随机密钥,提高登录认证的安全等级。首先对云计算登录认证系统结构进行分析,然后以网络公共数据库中的指纹图像为例,进行分形变幻环运算,生成伪随机序列,再将这些序列加密并通过UDP发送给服务器端进行认证,最后进行实例仿真。     

一种能量高效的无线传感器网络拓扑控制算法

通过对现有拓扑控制算法的研究,针对无线传感器网络中节点能耗分布不均匀的问题,提出了一种能量高效的拓扑控制算法(EETCA)。该算法以均衡全局能耗为目标,综合考虑了节点的剩余能量、簇的规模、数据最优传输跳数等因素,避免了部分节点能量消耗过快,从而有效地均衡网络负载。仿真结果表明:EETCA在能耗均衡方面均优于原来的算法,延长了无线传感器网络的生命周期。     

四相永磁容错电机短路故障容错策略

四相永磁容错电机采用被容错齿隔开的集中式绕组结构,本质上具有一定的容错能力和故障出现后连续运行的能力.针对H桥和星形这两种驱动拓扑结构,在发生单相绕组出线端部短路时,以容错控制后的转矩满足正常需求为目标,分别采用直接转矩补偿方法和旋转磁动势不变方法进行容错控制;对两种容错控制策略进行了推导和对比分析,并对相关结果进行了磁-路联合仿真计算,验证了理论分析的正确性.     

Allowable delay bound for consensus of linear multi-agent systems with communication delay

This paper studies the consensus of a group of linear dynamic agents with a uniform communication delay and focuses on searching an allowable delay bound. As long as the delay is less than this bound, there exist linear feedback consensus protocols driving the multi-agent system to achieve consensus. Both fixed and switching topology cases are investigated. In both cases, the consensus problem is converted to the robust stability problem of corresponding uncertain state-delayed systems. By using Lyapunov–Krasovskii functional analysis, consensus conditions which contain the feedback gain conditions and delay conditions are proposed for systems over fixed and switching topologies, respectively. Furthermore, allowable delay bounds are obtained for both systems by solving the optimal robust stabilisation problems. Numerical examples are given to illustrate the results.     

A trustworthy QoS-based collaborative filtering approach for web service discovery

Many network services which process a large quantity of data and knowledge are available in the distributed network environment, and provide applications to users based on Service-Oriented Architecture (SOA) and Web services technology. Therefore, a useful web service discovery approach for data and knowledge discovery process in the complex network environment is a very significant issue. Using the traditional keyword-based search method, users find it difficult to choose the best web services from those with similar functionalities. In addition, in an untrustworthy real world environment, the QoS-based service discovery approach cannot verify the correctness of the web services’ Quality of Service (QoS) values, since such values guaranteed by a service provider are different from the real ones. This work proposes a trustworthy two-phase web service discovery mechanism based on QoS and collaborative filtering, which discovers and recommends the needed web services effectively for users in the distributed environment, and also solves the problem of services with incorrect QoS information. In the experiment, the theoretical analysis and simulation experiment results show that the proposed method can accurately recommend the needed services to users, and improve the recommendation quality.     

Tool path generation framework for accurate manufacture of complex 3D sheet metal parts using single point incremental forming

The prototyping of complex sheet metal parts using single point incremental forming (SPIF) requires the generation of optimal tool paths and/or tool path sequences that ensure that the formed part is within geometric design specifications. The presence of a multitude of features on complex parts leads to multiple inaccuracy inducing phenomena occurring simultaneously due to interactions between the features. This paper proposes a network analysis methodology using topological conceptual graphs to capture the effects of different phenomena on the final accuracy of a sheet metal part manufactured by SPIF. Using this framework optimized tool paths can be generated that compensate for the inaccuracy inducing behavior. Tool path generation algorithms to create partial tool paths that account for the accuracy of specific features in the part based on the proposed framework are also presented. Finally, the creation of integrated tool paths maintaining complementarity between tool paths and desired continuity behavior using non-uniform cubic B-splines is illustrated. A number of case studies demonstrating the applicability of the integrated framework are discussed, where the maximum deviations in the part are significantly reduced and the average absolute deviations for the complete part are brought down to less than 0.5 mm.     

基于概率主题模型的物联网服务发现

针对物联网中服务数量的大规模性、服务描述的异构性以及设备服务的资源高度受限性和移动性等特点,提出了一种基于概率主题模型的物联网服务发现方法.该方法的主要特点是：1） 利用英文Wikipedia 构建高质量的主题模型,并对类似短文本的服务文本描述进行语义扩充,使主题模型能够更有效地估计服务文本描述的隐含主题;2） 提出利用非参数主题模型学习服务文本的隐含主题,降低模型训练时间;3） 利用服务隐含主题对服务进行自动分类和文本相似度计算,快速减少服务匹配数量,加速服务文本相似度计算;4） 提出能够同时支持WSDL-based 和RESTful 两种物联网服务的signature 匹配算法.实验结果表明：与现有的物联网服务发现方法相比,该方法的准确率（precision）和归一化折损累积增益（NDCG）都有较大幅度的提高.     

基于自然语言处理的算法知识名称发现

网络中的很多程序资源在知识概念上有内在的联系,却没有超链接将它们连接在一起。将网络程序资源中的算法知识名称获取出来,组织成一个算法知识专家库文件,用于识别程序设计资源所含的知识点,即可将程序设计资源按知识点相互联系。为了自动获取程序资源中的算法知识名称,提出一种基于自然语言处理的算法知识名称发现方法。通过发现含有算法知识名称语句的字符串模式,从程序资源中提取可能含算法知识名称的字符串,从中找出最有可能出现在算法知识名称中的分词,并根据这些分词获取算法知识名称。实验结果表明,与原有人工整理出的算法知识名称集合相比,该方法新增了11.2%的算法知识点和13.6%的算法知识名称。