局域网服务优化和安全配置

局域网是信息化网络不可分割的重要组成部分,其后台服务优化和安全配置是发挥其功能作用的关键。本文注重从终端客户机上配合服务器着手,综合服务功能的启动选择和安全设置法、组策略法、端口关闭法四个方面详细论述局域网服务优化和安全配置。     

一个基于Web Service的数据交换系统的设计

针对基于Web Service的数据交换系统的具体设计,提出了其中的两个技术关键即"基于WSDL的数据交换标准的制定"以及"可视化界面定义的数据转化方式",探讨了其实现方法。     

Process-context aware matchmaking for web service composition

Web service composition can help software developer design more powerful and flexible applications according to requirements of enterprise. But during compositing, how to discover suitable web services is a critical problem in design and implementing application-oriented web service technologies. The traditional keyword-based matchmaking approach is difficult to help developer to find suitable service. Current researches find that to attaching semantics to each registered service can help improve the precision of matchmaking. The improvement can help developer find more suitable service for business process. This paper proposes a novel approach of semantics-based matchmaking, which is named process-context aware matchmaking. The process-context aware matchmaking discovers the suitable service during web service composite modeling. During matchmaking, the approach utilizes not only semantics of technical process but also that of business process of a registered service, thus further improving the precision of matchmaking. We integrate the process-context aware matchmaking with business-process-driven web service composition in an integrated development environment based on Eclipse. The performance evaluation shows that performance overhead of this novel approach is acceptable.     

Edge-limited scalable QoS flow set-up

Although the Differentiated Services architecture supports scalable packet forwarding based on aggregate flows, the detailed procedure of Quality of Service (QoS) flow set-up within this architecture has not been well established. In this paper we explore the possibility of a scalable QoS flow set-up using a sink-tree paradigm. The paradigm initially constructs a sink tree at each egress edge router using network topology and bandwidth information provided by a QoS extended version of Open Shortest Path First (OSPF), which is a widely used link-state routing protocol. Our sink-tree paradigm dynamically reallocates network bandwidths online according to traffic demands. As a consequence, our paradigm easily supports QoS routing, resource allocation, and admission control at ingress edge routers without consulting core routers in a way that the QoS flow set-up time and overhead are minimized. Simulation results are very encouraging in that the proposed methodology requires significantly less communication overhead in setting up QoS flows compared to the traditional per-flow signaling-based methodology while still maintaining high resource utilization.     

A QoS-driven approach for service-oriented device anycasting in ubiquitous environments

The vision of pervasive computing is to let users enjoy ICT-enabled services in an “any time, anywhere, on any device” manner. It aims to supply ubiquitous services through communications among a set of devices deployed in a ubiquitous environment. Due to the diverse QoS needs of different kinds of ubiquitous services and users, it is a critical challenge to select an optimal set of devices with the objective of achieving service-specific QoS goals like low packet loss, short packet delay, and high energy efficiency. In this paper, the problem is first formulated as the service-oriented device anycasting problem (SDAP) and then proved as an NP-complete problem. By adopting a tree-based service representation model, Basu et al. proposed the dynamic task-embedding anycasting (DTA) approach. This approach effectively solves the SDAP in a distributed way. However, the service quality is likely sacrificed because the tree scheme does not sufficiently describe a ubiquitous service. In this paper, we propose a novel approach called the service-oriented device anycasting (SDA) approach that adopts a graph-based service representation model called the service profile (SP). By introducing a layered structure into the SP, the SDA approach can reach a compromise between service quality and computational complexity. In addition, the QoS-driven utility function is proposed to quantify service quality by matching the capabilities of heterogeneous devices to various QoS needs. Finally, the simulation results show that the SDA approach outperforms the DTA approach by saving roughly 20% of device energy and prolonging the network lifetime. Packet loss and packet delay are also improved by roughly 25% and 8%, respectively. The advantage of the SDA approach is more obvious in environments with highly mobile devices and multiple users.     

Inchworm robot grippers for clothes manipulation

Manipulating deformable objects like clothes, plastic, and paper by a robot is very challenging. This paper focuses on clothes manipulation as an example. A tracing manipulation method is used here to find a corner of the clothes. In this paper, tracing refers to tracing the clothes’ edge, with the robot’s movement based on feedback from sensors. One difficulty during this edge tracing is to make the robot trace smoothly and speedily without dropping the clothes in the process. This is due to the fact that deformable objects are sensitive to contact forces. A solution to this problem is to design a special robot gripper that can trace the clothes without having to worry about the clothes slipping away. In this paper, the development of inchworm-type grippers is proposed. Two sets of grippers inside a robot hand will allow the robot to trace the clothes more freely because there will always be a gripper firmly holding the clothes at any time. A unique tracing method for towel spreading using the inchworm grippers is also discussed. Experimental results have demonstrated the effectiveness of both the proposed grippers and also the algorithm. This work was presented in part at the 12th International Symposium on Artificial Life and Robotics, Oita, Japan, January 25–27, 2007     

Trust force-based service selection in pervasive computing environments

Trust is an important aspect of decision making for pervasive applications and it is important to choose and use services efficiently in pervasive computing environments. Trust force is presented to specify trust relationships among interactive entities in a pervasive computing environment by using experience and knowledge in a social network and the coulomb＇s law in real word. Based on trust force, a Trust Management and Service Selection model are presented, named TMSS. TMSS was tested and the experimental results show that our method for selecting service is not only more efficient than traditional and heuristic methods, but also can identify good services from bad ones.     

A distributed PSO–SVM hybrid system with feature selection and parameter optimization

This study proposed a novel PSO–SVM model that hybridized the particle swarm optimization (PSO) and support vector machines (SVM) to improve the classification accuracy with a small and appropriate feature subset. This optimization mechanism combined the discrete PSO with the continuous-valued PSO to simultaneously optimize the input feature subset selection and the SVM kernel parameter setting. The hybrid PSO–SVM data mining system was implemented via a distributed architecture using the web service technology to reduce the computational time. In a heterogeneous computing environment, the PSO optimization was performed on the application server and the SVM model was trained on the client (agent) computer. The experimental results showed the proposed approach can correctly select the discriminating input features and also achieve high classification accuracy.     

Service Discovery and Negotiation With COWS

To provide formal foundations to current (web) services technologies, we put forward using COWS, a process calculus for specifying, combining and analysing services, as a uniform formalism for modelling all the relevant phases of the life cycle of service-oriented applications, such as publication, discovery, negotiation, deployment and execution. In this paper, we show that constraints and operations on them can be smoothly incorporated in COWS, and propose a disciplined way to model multisets of constraints and to manipulate them through appropriate interaction protocols. Therefore, we demonstrate that also QoS requirement specifications and SLA achievements, and the phases of dynamic service discovery and negotiation can be comfortably modelled in COWS. We illustrate our approach through a scenario for a service-based web hosting provider.     

Are our homes ready for services? A domotic infrastructure based on the Web service stack

The increase in computational power and the networking abilities of home appliances are revolutionizing the way we interact with our homes. This trend is growing stronger and opening a number of technological challenges. From the point of view of distributed systems, there is a need to design architectures for enhancing the comfort and safety of the home, which deals with issues of heterogeneity, scalability and openness. By considering the evolution of domotic research and projects, we advocate a role for Web services in the domestic network. We ground our claim by proposing a concrete architecture for a home in which the health of an elder is monitored. The architecture is implemented on a heterogeneous set of devices, which allows us to evaluate it and draw conclusions on the feasibility of using service-oriented approaches in ubiquitous computing.