一个软件服务协同中的信任管理框架设计

Internet-based Web application systems are gradually built as software service coordination systems. In an open, dynamic and collaborative application environment, traditional methods assumed with closeness, centralization and independence are not able to cope with these security problems efficiently. Trust management is a new method for dealing with security issues of open, distributed network application system. However, the traditional policy-based trust management systems have some shortcomings, i.e. complex in policy making, unable to deal with negative se-curity credentials, etc. So, we design a trust management framework in combination with subjective trust model for software service coordination and security decision in Internet environment. This trust management framework has characteristics of operability, reasonability, and flexibility in policy setting.     

On environment-driven software model for Internetware

Internetware is envisioned as a general software paradigm for the application style of resources integration and sharing in the open, dynamic and uncertain platforms such as the Internet. Continuing the agent-based Internetware model presented in a previous paper, in this paper, after an analysis of the behavioral patterns and the technical challenges of environment-driven applications, a software-structuring model is proposed for environment-driven Internetware applications. A series of explorations on the enabling techniques for the model, especially the modeling, management and utilization of context information are presented. Several proto-typical systems have also been built to prove the concepts and evaluate the techniques. These research efforts make a further step toward the Internetware paradigm by providing an initial framework for the construction of context-aware and self-adaptive software application systems in the open network environment.     

Mobile agent-enabled framework for structuring and building distributed systems on the internet

Mobile agent has shown its promise as a powerful means to complement and enhance existing technology in various application areas. In particular, existing work has demonstrated that MA can simplify the development and improve the performance of certain classes of distributed applications, especially for those running on a wide-area, heterogeneous, and dynamic networking environment like the Internet. In our previous work, we extended the application of MA to the design of distributed control functions, which require the maintenance of logical relationship among and/or coordination of proc- essing entities in a distributed system. A novel framework is presented for structuring and building distributed systems, which use cooperating mobile agents as an aid to carry out coordination and cooperation tasks in distributed systems. The framework has been used for designing various distributed control functions such as load balancing and mutual ex- clusion in our previous work. In this paper, we use the framework to propose a novel ap- proach to detecting deadlocks in distributed system by using mobile agents, which dem- onstrates the advantage of being adaptive and flexible of mobile agents. We first describe the MAEDD (Mobile Agent Enabled Deadlock Detection) scheme, in which mobile agents are dispatched to collect and analyze deadlock information distributed across the network sites and, based on the analysis, to detect and resolve deadlocks. Then the design of an adaptive hybrid algorithm derived from the framework is presented. The algorithm can dynamically adapt itself to the changes in system state by using different deadlock detec- tion strategies. The performance of the proposed algorithm has been evaluated using simulations. The results show that the algorithm can outperform existing algorithms that use a fixed deadlock detection strategy.     

Towards evolvable Internet architecture-design constraints and models analysis

There is a general consensus about the success of Internet architecture in academia and industry. However, with the development of diversified application, the existing Internet architecture is facing more and more challenges in scalability, security, mobility and performance. A novel evolvable Internet architecture framework is proposed in this paper to meet the continuous changing application requirements. The basic idea of evolvability is relaxing the constraints that limit the development of the architecture while adhering to the core design principles of the Internet. Three important design constraints used to ensure the construction of the evolvable architecture, including the evolvability constraint, the economic adaptability constraint and the manageability constraint, are comprehensively described. We consider that the evolvable architecture can be developed from the network layer under these design constraints. What＇s more, we believe that the address system is the foundation of the Internet. Therefore, we propose a general address platform which provides a more open and efficient network environment for the research and development of the evolvable architecture.     

A Graphics System Distributed across a Local Area Network

Design of a general purpose graphics system in a computer network environment requiresthat the architectural design of the graphics system be suited to such an environment and theadvantages of the network environment be taken for distributed graphics processing and thesharing of resources. An architectural model is designed to meet these requirements. The modelis characterised by the distribution on the machines in the network of graphics facilitiesprovided by several graphics subsystems with various capabilities but compatible functionality,and the distributed processing of graphics across the network. This design structure has beenshown to be viable by using it as the basis for the implementation of the graphics system for theMU6G network at University of Manchester. The design methodology and the structure of thegraphics system are described in the paper.     

分布式协作模型及应用研究

With the development of the Web technology,the application environment has acquired many new characters such as dynamic, openness,distribution and information uncertainty.The processing mode of application systems is more complicated than ever.For example,it requires application systems to have more community processing ability,interactive ability,distributed processing ability and collaborative ability.Accordingly the research and development of the computer application system transited from client/server information processing system into distributed collaborative processing system based on Web.Especially in the environment where the information and resources are highly distributed,the accomplishment of complicated tasks is dependent more on the resources coordination,information sharing and coordinator collaboration.The collaboration is one aspect of the group behavior and its goal is to provide a optimal method to utilize the resource through the information interaction and to solve the task which couldn't be accomplished by each coordinator alone and get the more total benefits than the sum of each benefit.The collaboration problem is the important one for distributed tasks processing.This paper surveys,the research and application status of distributed collaborative models and several representative architectures of distributed collaborative processing are proposed.However,the existing problems and the future researching direction are presented.     

Framework and Algorithm for Grid QoS Infrastructure in Optical Burst Switching Networks with GMPLS Support

Recently, in order to satisfy the requirements of all kinds of high-performance computing and transmission applications, researchers begin to focus on grid technology and have made lots of research work. Among the corresponding aspects, a complete and feasible grid framework is rather pivotal to provide nontrivial QoS guarantee in this grid architecture, which should include Grid application layer, Grid middleware layer, and network layer, even the concrete resources. In this paper, a novel architecture for Grid QoS infrastructure is proposed based on other architectures suggested by Globus project, Global Grid forum and IETF. The architecture is complete and consists of three QoS layers from top to bottom including Grid application, middleware and network layer. In addition, the algorithm based on advance resource reservation is also provided and described in optical burst switching （OBS） networks with GMPLS（Generalized Multi-Protocol Label Switching） support. The algorithm with pruned topology and shared risk links group constraints is designed for supporting the realization of routing function in the architecture. Extensive simulations with dynamic traffic are made to prove the validity and properness.     

Consensus of high-order dynamic multi-agent systems with switching topology and time-varying delays

This paper studies the consensus problems for a group of agents with switching topology and time-varying communication delays, where the dynamics of agents is modeled as a high-order integrator. A linear distributed consensus protocol is proposed, which only depends on the agent’s own information and its neighbors’ partial information. By introducing a decomposition of the state vector and performing a state space transformation, the closed-loop dynamics of the multi-agent system is converted into two decoupled subsystems. Based on the decoupled subsystems, some sufficient conditions for the convergence to consensus are established, which provide the upper bounds on the admissible communication delays. Also, the explicit expression of the consensus state is derived. Moreover, the results on the consensus seeking of the group of high-order agents have been extended to a network of agents with dynamics modeled as a completely controllable linear time-invariant system. It is proved that the convergence to consensus of this network is equivalent to that of the group of high-order agents. Finally, some numerical examples are given to demonstrate the effectiveness of the main results.     

CORBA-Based Analysis of Multi Agent Behavior

An agent is a computer software that is capable of taking independent action on behalf of its user or owner. It is an entity with goals, actions and domain knowledge, situated in an environment. Multiagent systems comprises of multiple autonomous, interacting computer software, or agents. These systems can successfully emulate the entities active in a distributed environment. The analysis of multiagent behavior has been studied in this paper based on a specific board game problem similar to the famous problem of GO. In this paper a framework is developed to define the states of the multiagent entities and measure the convergence metrics for this problem. An analysis of the changes of states leading to the goal state is also made. We support our study of multiagent behavior by simulations based on a CORBA framework in order to substantiate our findings.     

Software Operational Profile Based Test Case Allocation Using Fuzzy Logic

Software operational profile (SOP) is used in software reliability prediction,software quality assessment,performance analysis of software,test case allocation,determination of"when to stop testing,"etc.Due to the limited data resources and large efforts required to collect and convert the gathered data into point estimates,reluctance is observed by the software professionals to develop the SOP.A framework is proposed to develop SOP using fuzzy logic,which requires usage data in the form of linguistics.The resulting profile is named fuzzy software operational profile (FSOP).Based on this work,this paper proposes a generalized approach for the allocation of test cases,in which occurrence probability of operations obtained from FSOP are combined with the criticality of the operations using fuzzy inference system (FIS).Traditional methods for the allocation of test cases do not consider the application in which software operates.This is intuitively incorrect.To solve this problem,allocation of test cases with respect to software application using the FIS model is also proposed in this paper.     

Middleware infrastructure for parallel and distributed programming models in heterogeneous systems

We introduce a middleware infrastructure that provides software services for developing and deploying high-performance parallel programming models and distributed applications on clusters and networked heterogeneous systems. This middleware infrastructure utilizes distributed agents residing on the participating machines and communicating with one another to perform the required functions. An intensive study of the parallel programming models in Java has helped identify the common requirements for a runtime support environment, which we used to define the middleware functionality. A Java-based prototype, based on this architecture, has been developed along with a Java object-passing interface (JOPI) class library. Since this system is written completely in Java, it is portable and allows executing programs in parallel across multiple heterogeneous platforms. With the middleware infrastructure, users need not deal with the mechanisms of deploying and loading user classes on the heterogeneous system. Moreover, details of scheduling, controlling, monitoring, and executing user jobs are hidden, while the management of system resources is made transparent to the user. Such uniform services are essential for facilitating the development and deployment of scalable high-performance Java applications on clusters and heterogeneous systems. An initial deployment of a parallel Java programming model over a heterogeneous, distributed system shows good performance results. In addition, a framework for the agents' startup mechanism and organization is introduced to provide scalable deployment and communication among the agents.     

基于Nginx-F5的双架构应用并行及流量切换方案

随着业务量和功能需求的不断增长, 各大业务系统的应用正逐步实现Spring Boot架构到Spring Cloud微服务架构的升级. 由于版本的变更度较大, 需要经过充分的内部测试与对外联调才能正式上线. 在现有联调环境存在DMZ域机器资源有限, 以及尽量减少公网暴露面等要求下, 文章提出了基于Nginx-F5的双架构应用并行及流量切换方案, 使测试系统同时具备Boot和Cloud两种架构应用的对外联调测试功能. 该方案将外部商户的请求按照商户编码、业务类型或省代码等属性标识及一定的百分比进行拆分并转发至微服务应用系统, 使微服务版本的应用获得充分的调测, 为需要进行大版本并行测试的系统扩展和建设提供参考.     

基于CAFISE Framework的高适应性面向服务软件开发

在企业及电子政务应用中,由资源分布异构及需求动态变化而产生的问题越来越严重,如何让应用快速适应这些变化一直是人们关注的一个研究难题.首先给出了一个面向服务的支持业务端编程的适应性软件结构框架CAFISE(convergent approach for information system evolution)Framework,然后给出了基于该框架的面向服务的适应性软件开发方法.CAFISE Framework对异构资源的服务化、业务化及开放动态的面向服务软件体系结构提供了较好的支持.基于该结构框架的开发方法,从对影响软件的环境要素分析入手,通过质量属性驱动的体系结构分析,重点针对应用要适应的变化进行结构设计,最终通过以体系结构为基础的业务端编程,实现面向服务应用的即时开发与演化.在实际项目中的使用及实验证明:用该框架和方法开发的面向服务应用,能够较好地适应异构资源的动态变化及用户业务变更,能以较低的代价实现企业及电子政务面向服务应用的持续演化.     

ImAge: an extensible agent-based architecture for image retrieval

We present an open and extensible architecture, ImAge, for content-based image retrieval in a distributed environment. The architecture proposes the use of system components with standard public interfaces for implementing retrieval functionality. The standardization of the components and their encapsulation in autonomous software agents result in functional stratification and easy extensibility. Collaboration of the independent retrieval resources in ImAge results in enhanced system capability. Reuse of existing retrieval resources is achieved by encapsulating them in agents with standard interfaces. The addition of independent agents with domain knowledege adds the capability of processing conceptual queries, while reusing the existing system components for feature-based retrieval. A communication protocol allows the declaration of the capabilities of the system components and negotiations for optimal resource selection for solving a retrieval problem. The use of mobile agents alleviates network bottlenecks. This paper describes a prototype implementation that validates the architecture.     

一个科学计算领域的面向对象并行应用框架

本文讨论了一个面向对象的分布式并行应用开发环境ＰＯＯＭＡ。     

Neural network‐based multi‐agent approach for scheduling in distributed systems

A distributed system consists of a collection of autonomous heterogeneous resources that provide resource sharing and a common platform for running parallel compute‐intensive applications. The different application characteristics combined with the heterogeneity and performance variations of the distributed system make it difficult to find the optimal set of needed resources. When deployed, user applications are usually handled by application domain experts or system administrators who depending on the infrastructure provide a scheduling strategy for selecting the best candidate resource over a set of available resources. However, the provided strategy is usually generic, aimed at handling a wide array of applications and does not take into consideration specific application resource requirements. As such, an intelligent method for selecting the best resources based on expert knowledge is needed. In this paper, we propose a neural network‐based multi‐agent resource selection technique capable of mimicking the services of an expert user. In addition, to cope with the geographical distribution of the underlying system, we employ a multi‐agent coordination mechanism. The proposed neural network‐based scheduling framework combined with the multi‐agent intelligence is a unique approach to efficiently deal with the resource selection problem. Results run on a simulated environment show the efficiency of our proposed method. Several scheduling simulations were conducted to compare the performance of some conventional resource selection methods against the proposed agent‐based neural network technique. The results obtained indicate that the agent‐based approach outperformed the classical algorithms by reducing the amount of time required to search for suitable resources irrespective of the resource size. Copyright © 2016 John Wiley & Sons, Ltd.     

基于TCP/IP的分布式监控系统的研究与开发

根据对企业控制网络与数据网络一体化技术的研究,文章提出了一种全TCP/IP协议的分布式监控系统结构框架,利用有关的硬件与软件技术,进行了设计与开发实现,并对分布式监控系统的核心通讯模块中多通讯线程的管理与调度进行了探讨与实现。该方案解决了传统系统结构下的许多问题,从而在企业分布式虚拟环境中,对各种资源能更实时、准确、可靠地访问及有效地管理,具备了更好的性能。     

A survey of distributed optimization

In distributed optimization of multi-agent systems, agents cooperate to minimize a global function which is a sum of local objective functions. Motivated by applications including power systems, sensor networks, smart buildings, and smart manufacturing, various distributed optimization algorithms have been developed. In these algorithms, each agent performs local computation based on its own information and information received from its neighboring agents through the underlying communication network, so that the optimization problem can be solved in a distributed manner. This survey paper aims to offer a detailed overview of existing distributed optimization algorithms and their applications in power systems. More specifically, we first review discrete-time and continuous-time distributed optimization algorithms for undirected graphs. We then discuss how to extend these algorithms in various directions to handle more realistic scenarios. Finally, we focus on the application of distributed optimization in the optimal coordination of distributed energy resources.     

High-level abstractions for message-passing parallel programming

Large-scale scientific and engineering computation problems are usually complex and consequently the development of parallel programs for solving these problems is a difficult task. In this paper, we describe the graph-oriented programming (GOP) model and environment for building and evaluating parallel applications. The GOP model provides higher level abstractions for message-passing parallel programming and the software environment offers tools which can ease programmers for parallelizing, writing, and deploying scientific and engineering computing applications. We discuss the motivations and various issues in developing the model and the software environment, present the design of the system architecture and the components, and describe the evaluation of the environment implemented on top of MPI with a sample parallel scientific application program. With the support of the high-level abstractions provided by the proposed GOP environment, programming of parallel applications on various parallel architectures can be greatly simplified.     

一种分布式协同开发环境的分布并行开发技术

随着网络技术和软件规模的发展,软件分布式开发的需求越来越迫切。SDCEE是一个软件分布式协同开发环境,它使用户可通过浏览器参与项目全过程的开发。本文论述了该系统的体系结构和分布并行开发模型。