Yang Fangchun

A Policy-Driven Distributed Framework for Monitoring Quality of Web Services

Quality of Service (QoS) characterizes the non-functional aspects of Web service, which is the key factor for satisfying service users and has to be carefully considered in service oriented architecture. There has been a lot of works on QoS description and service selection by QoS information. However, two issues have not been substantially explored in QoS management-how to collect QoS information from running services, and how to dynamically adapt service provisioning with run-time QoS information. Moreover, current monitoring approaches are focused on monitoring the service interaction in a single domain, while cross-domain monitoring has not been studied yet. In this paper, we present a policy-driven monitoring framework for collecting QoS information and adapting service provisioning for cross-domain service interaction. The monitor is built on our distributed QoS registry-Q-Peer. The monitor is user-centric, metric-oriented, feedback-enabled and loosely-coupled with service providers. Services are observed by capturing interaction messages, so the monitoring approach has no impact to service providers. The framework supports dynamic configuration of monitoring metrics for both single service and cross-domain composite service. It can be used as a reliable third-party QoS monitor for Web services.

Uncertain QoS-Aware Skyline Service Selection Based on Cloud Model

Because traditional QoS-aware Web service selection approach cannot ensure the reliability and the real-time of service selection,this paper proposes an uncertain QoS-aware Skyline service selection approach based on cloud model.The approach first uses cloud model to compute the uncertainty of QoS and then adopts Skyline computing to extract Skyline services from Web services to prune redundant services.Finally,mixed integer programming is employed to perform service selection from Skyline services.The study evaluates the approach experimentally using both real and synthetically generated datasets.The experimental results show that the proposed approach can accomplish service selection for users reliably and quickly.

Research on PSO based multiple UAVs real-time task assignment

Unmanned aerial vehicles (UAVs) have the capability of executing various missions. However, the capability of single UAV is limited. It may require multiple UAVs to form coalition and prosecute tasks cooperatively. So, multiple UAVs task assignment faces the problems of: (a) satisfy the heterogeneous resource requirement and (b) satisfy the task prosecution for real-time requirement. In this paper, a PSO based algorithm DCAA is proposed for UAVs task assignment. UAVs search for targets and try to form coalition when they find targets. Once formed, the coalition members will adjust their paths to prosecute the target simultaneously to induce maximum damage. The simulation results show that using the proposed algorithm, UAVs can complete mission in short time. And the mission completion percentage keeps at a high level. The proposed algorithm is suitable for real-time application.

A study on call model of soft-switch

The soft-switch is an important entity in NGN. How to flexibly provide abundant applications and adapt new protocols presents an essential problem. This paper proposes a new enhanced multiparty call model for soft-switch. Firstly, the reasons why IN call model or H.323 call model are not suitable for soft-switch are analyzed. Secondly, a soft-switch call model is addressed. Finally, a simple multiparty service is illustrated using this call model.

Fuzzy evaluation of SLA-oriented QoSM (the quality of service management) in NGN

The quality of service management-QoSM is a new conception from NGN service layer. To evaluate QoSM efficiently, it is necessary and elementary to define an evaluation metrics and find an evaluation method. First, the evaluation metrics for QoSM based on SLA service management contents is proposed. Then a fuzzy evaluating method to evaluate QoSM based on SLA-oriented service management metrics is designed. At last, an example of evaluating is described to illuminate that the fuzzy evaluating method for the QoSM of NGN is useful and correct.

Analysis on SIP mobility of double user agent servers

As a convergence of telecom network and Internet, next generation network encounters the mobility support as well. This paper concentrates on exploring the SIP protocol, especially the SIP mobility support issue, on the basis of which and in accordance with the specific characteristics of telecom operations, a framework of double user agent servers is presented hoping to improve the mobility support of SIP.

Research on the interworking between CORBA and intelligent network

To reduce costs and time for developing new services, the use of distributed object-oriented technology such as CORBA is recommended. This article discusses the introduction of CORBA technology into the intelligent network. A pragmatic approach to the design of the IN/CORBA gateway is outlined in order to facilitate the smooth interworking between the IN and CORBA domain. The performance test data of such an IN/CORBA gateway are given finally.

A study on IN call model for the support of multimedia services in IP network

With the fast development of IP telephony, there is a need to quickly provide more powerful and competitive multimedia services in the IP network. A natural choice is to integrate the intelligent network and IP network and exploit the mature capabilities of service creation and service deployment of the intelligent network in the IP network. This paper addresses a new call model between the intelligent network and the IP network for supporting the advanced multimedia service in the IP network using H.323. Firstly, the reason why the existing IN basic call state model is not suitable to model H.323 signaling are analyzed, then an enhanced call model based layered structure in order to fully exploit the advantages introduced by H.323 is proposed. Finally, we present an approach of the IP-SSP architecture based on the proposed model to fulfill the integration between the IN and IP.

An intelligent network architecture based on active network technology

The emerging technology of active networks is one for future directions of communication networks, where users can inject their programs into the network infrastructure. The increasing number of supplementary services, the development of new types of services and several years of usage show some drawbacks of intelligent networks (IN). This paper looks at the impact of active network technology on the traditional IN. We present a novel IN architecture enhanced by active network technology, which can not only overcome some drawbacks of traditional IN, but can also keep existing resources. We also describe a way of supporting intelligent services based on active packets (capsules), which results in better performance and fault tolerance compared to traditional IN service implementations.

Research on Packet Tagging Using the Attributes of Data Stream

For the important role of packets in the network management and security applications, many researches have been applied to network packet. How to record and store the packets in an efficient structure is a problem in this field. This paper focuses on the study of network packet tagging technique. Based on existing research, this paper presents a tagging method using the attributes of data stream. This method takes data stream as a unit to record the data of raw packets and make a data structure for packets storage. Through experiment, it’s showing that this method makes effective management and clear description for the packets, supports network applications basing on network packets. This method has low storage cost, efficient query process and is highly scalable over existing methods.