Virtual Organization Support within a Grid-Wide Operating System

Despite grids' popularity, virtual organizations (VOs) have yet to become a commodity technology in modern computing environments due to the complexity of managing them and difficulty of assuring user and VO isolation. Here, the authors describe the VO management approach taken by XtreemOS, a new grid operating system with native support for VOs that supports a wide range of computing resources, from clusters to mobiles. They also discuss the requirements for the VO model and management within XtreemOS and introduce an expandable VO model and a system architecture that supports it.     

A framework for virtual organization requirements

Virtual organizations (VOs) are formed by an alliance of organizations linked by a partnership for dealing with emerging challenges. Information and communication technologies play a fundamental role facilitating cooperation, communication and collaboration among the VO members. The formal identification and representation of Requirements Engineering (RE) for one organization have been researched to a large extent along with several elicitation techniques. However, these techniques are not adequate for covering the major challenges of RE for VO. We explore the work done in the management and RE fields to propose a model-based framework for eliciting VOs’ requirements. The goal is to analyze the VO from two points of view: border (intra-organizational, inter-organizational and extra-organizational) and abstract (intentional, organizational and operational). This article includes the framework validation with a case study and a transformation process to develop partial Business Process Diagram from the intentional models.     

面向方面的MDA开发方法

MDA中提出了两种重要的模型:平台无关模型和平台相关模型.PIM是反映系统功能性需求的业务模型,PSM是PIM针对实现技术的映射.对于系统的非功能性需求,如安全性、性能、内存管理和通信等,MDA中未提出明确的模型.借鉴面向方面的编程(AOP)的思想,提出了一种基于UML Profile的"方面"建模表示法,用于在MDA中对系统的非功能性需求建立方面模型(AOM),并在MDA方法中增加模型编织(Weaver)环节,得到功能更为强大的基于方面的MDA开发方法.     

SPL Conqueror: Toward optimization of non-functional properties in software product lines

A software product line (SPL) is a family of related programs of a domain. The programs of an SPL are distinguished in terms of features, which are end-user visible characteristics of programs. Based on a selection of features, stakeholders can derive tailor-made programs that satisfy functional requirements. Besides functional requirements, different application scenarios raise the need for optimizing non-functional properties of a variant. The diversity of application scenarios leads to heterogeneous optimization goals with respect to non-functional properties (e.g., performance vs. footprint vs. energy optimized variants). Hence, an SPL has to satisfy different and sometimes contradicting requirements regarding non-functional properties. Usually, the actually required non-functional properties are not known before product derivation and can vary for each application scenario and customer. Allowing stakeholders to derive optimized variants requires us to measure non-functional properties after the SPL is developed. Unfortunately, the high variability provided by SPLs complicates measurement and optimization of non-functional properties due to a large variant space. With SPL Conqueror, we provide a holistic approach to optimize non-functional properties in SPL engineering. We show how non-functional properties can be qualitatively specified and quantitatively measured in the context of SPLs. Furthermore, we discuss the variant-derivation process in SPL Conqueror that reduces the effort of computing an optimal variant. We demonstrate the applicability of our approach by means of nine case studies of a broad range of application domains (e.g., database management and operating systems). Moreover, we show that SPL Conqueror is implementation and language independent by using SPLs that are implemented with different mechanisms, such as conditional compilation and feature-oriented programming.     

Security architecture for virtual organizations of business web services

Virtual organizations (VO) temporarily aggregate resources of different domains to achieve a common goal. Web services are being positioned as the technological framework for achieving this aggregation in the context of cross-organizational business applications. Numerous architectures have been proposed for securing VOs, mostly for scientific research, such that they do not address all the requirements of business-oriented applications. This paper describes these additional requirements and proposes a novel architecture and approach to managing VO access control policies. Business users can focus on designing business processes, exposing web services and managing their VO partnerships, while the architecture supports and secures the web service interactions involved.     

Requirement-oriented risk management for incremental software development

In incremental software development (ISD) functionalities are delivered incrementally and requirements keep on evolving across iterations. The requirements evolution involves the addition of new dependencies and conflicts among functional and non-functional requirements along with changes in priorities and dependency weights. This, in turn, demands refactoring the order of development of system components to minimize the impact of these changes. Neglecting the non-functional constraints in the software development process exposes it to risks that may accumulate across several iterations. In this research work, we propose a risk management framework for ISD processes that provides an estimate of risk exposure for the project when functional features are frozen while ignoring the associations with non-functional requirements. Our framework proposes suitable risk reduction strategies that work in tandem with the risk assessment module. We also provide a tool interface for our risk management framework.

     

Cross‐domain authorization for federated virtual organizations using the myVocs collaboration environment

This paper describes our experiences building and working with the reference implementation of myVocs (my Virtual Organization Collaboration System). myVocs provides a flexible environment for exploring new approaches to security, application development, and access control built from Internet services without a central identity repository. The myVocs framework enables virtual organization (VO) self‐management across unrelated security domains for multiple, unrelated VOs. By leveraging the emerging distributed identity management infrastructure. myVocs provides an accessible, secure collaborative environment using standards for federated identity management and open‐source software developed through the National Science Foundation Middleware Initiative. The Shibboleth software, an early implementation of the Organization for the Advancement of Structured Information Standards Security Assertion Markup Language standard for browser single sign‐on, provides the middleware needed to assert identity and attributes across domains so that access control decisions can be determined at each resource based on local policy. The eduPerson object class for lightweight directory access protocol (LDAP) provides standardized naming, format, and semantics for a global identifier. We have found that a Shibboleth deployment supporting VOs requires the addition of a new VO service component allowing VOs to manage their own membership and control access to their distributed resources. The myVocs system can be integrated with Grid authentication and authorization using GridShib. Copyright © 2008 John Wiley & Sons, Ltd.     

Functionality Aware Dynamic Composition of Web Services

The composition of the web service is a common technique to attain the best results of complex web tasks. The selection of appropriate web services, linking those services in the action flow and attaining the actual functionality of the task are the important factors to be considered. Even though different frameworks and methods have been proposed to dynamically compose web services, each method has its advantage and disadvantage over the other. Most of the methods give much importance to the Quality of Service (QoS) but fail to achieve the actual functionality after composition. This paper proposes a functionality-oriented composition technique for composing web services. Moreover, this method helps reach the extreme functionality of each web service in the composition towards customer satisfaction. Apart from considering the overall QoS of every single service, the non-functional parameters associated with these services are also considered for achieving the expected functionality. Each of these non-functional parameters has a vital role in the functional performance of the web service. The web services that satisfy the non-functional requirements are chosen to form the composition to attain the best performance. The list of services in the proposed composition method is different from the conventional one, which is composed based on the overall QoS. The non-functional parametric values, the QoS of each web service and the overall QoS after composition are evaluated for the proposed method and experimentally analyzed to prove their advantage over the others.     

A polymorphic service management scheme based on virtual object for ubiquitous computing environment

For the ubiquitous computing environment, an important assumption is that all the components in any specific environment are connected with each other. With this assumption, we introduce an effective scheme to provide a personalized service based on Virtual Personal World (VPW). Virtual Personal World (VPW) which is a model focused on service continuity with specially designed components. Previous ubiquitous frameworks have been concerned with the location where a user is provided any specific service. However those questions above are not the most important problems anymore in VPW. It concentrates on the point whether the services are successive or not, wherever a user goes to any place. Services are not regarded as a sum of functions which is embedded on any objects in any certain place. We conceptually define a resource management scheme based on a unified form of the object which participates in service provision, so called virtual object (VO). Thus the service can be described as the sum of functions of VOs. With our resource management scheme, users can utilize their required object as VO wherever it is located. And also, for better utilization of VPW service, we introduce a novel form of profiles and service provision scheme based on the polymorphism. Our simulation result shows that the Ratio of VPW pure service time is 0.15 % higher than conventional location based service. And also the possibility that users can meet adequate service he wants raised 29 % in our proposed VPW environment.     

Trust establishment in the formation of Virtual Organizations

Virtual Organizations (VOs) represent a new collaboration paradigm in which the participating entities pool resources, services, and information to achieve a common goal. VOs represent an interesting approach for companies to achieve new and profitable business opportunities by being able to dynamically partner with others. Thus, choosing the appropriate VO partners is a crucial aspect. Ensuring trustworthiness of the members is also fundamental for making the best decisions. In this paper, we show how trust negotiation represents an effective means to select the best possible members during different stages in the VO lifecycle. We base our discussion on concrete application scenarios and illustrate the tools created by us that integrate trust negotiation with a VO Management toolkit.     

System security requirements: A framework for early identification,specification and measurement of related software requirements

One of the responsibilities of developers is the early definition of non-functional requirements (NFR) at the system level and their related allocation as functional user requirements (FUR) at the software level. To identify some of the widely consensual security elements that could be used in a standards-based security framework, the security-related terminology and views from three sets of international standards (ECSS, IEEE and ISO) are analyzed and integrated. Next, the set of concepts adopted by ISO 19761 for describing software functionality at a lower level are introduced, thereby ensuring that the proposed framework is designed for measurement purposes as well. For the capture of security concepts, the proposed framework is designed using soft-goal interdependency graphs (SIG) and three main system NFR-security types: system availability, confidentiality and integrity. This standards-based system security framework at the function and service level can support software developers to derive such requirements in the early stages of the development process. Finally, an ATM example for the measurement of system security NFR allocated as software FUR within a service-oriented architecture (SOA) is presented.     

Object-oriented DBMS requirements

The requirements on an object-oriented DBMS for management of information in a large, complex enterprise are presented. These requirements aid in the achievement of an environment characterized by data sharing, open architectures, application and data portability, and assurance of data integrity. They were defined from the point of view of a user of the DBMS; therefore they describe the expected functionality of the DBMS and do not specify the method of implementation to achieve this functionality. They encompass requirements on the data model, query and data manipulation languages, the system architecure, interfaces to the system, change management, and transaction management.     

一种基于分层的网格资源发现模型

资源发现的质量与网格系统中资源的组织方式和查询消息的路由方式是密不可分的。随着P2P网络的兴起,许多新的概念和研究方向为网格相关研究提供了思路。该文引入了虚拟组织的相关概念,在此基础上将网格资源进行分层管理,提出了分层C&;G体系构架。针对资源查询的处理,给出了3个相关算法：IE算法,ID算法和IR算法。通过实验与传统算法进行了对比,结果表明其性能有了一定的提高。     

Toward automated feature model configuration with optimizing non-functional requirements

ContextA software product line is a family of software systems that share some common features but also have significant variabilities. A feature model is a variability modeling artifact, which represents differences among software products with respect to the variability relationships among their features. Having a feature model along with a reference model developed in the domain engineering lifecycle, a concrete product of the family is derived by binding the variation points in the feature model (called configuration process) and by instantiating the reference model.ObjectiveIn this work we address the feature model configuration problem and propose a framework to automatically select suitable features that satisfy both the functional and non-functional preferences and constraints of stakeholders. Additionally, interdependencies between various non-functional properties are taken into account in the framework.MethodThe proposed framework combines Analytical Hierarchy Process (AHP) and Fuzzy Cognitive Maps (FCM) to compute the non-functional properties weights based on stakeholders’ preferences and interdependencies between non-functional properties. Afterwards, Hierarchical Task Network (HTN) planning is applied to find the optimal feature model configuration.ResultOur approach improves state-of-art of feature model configuration by considering positive or negative impacts of the features on non-functional properties, the stakeholders’ preferences, and non-functional interdependencies. The approach presented in this paper extends earlier work presented in [1] from several distinct perspectives including mechanisms handling interdependencies between non-functional properties, proposing a novel tooling architecture, and offering visualization and interaction techniques for representing functional and non-functional aspects of feature models.Conclusionour experiments show the scalability of our configuration approach when considering both functional and non-functional requirements of stakeholders.     

一种鲁棒的视频分割算法

无论是在图象识别，还是在基于MPEG－4的图象压缩编码等应用领域，视频对象分割取是其中一个很重要的技术环节，为了在静止背景的情况下，能很好地解决多目标分割的问题，同时能进行单目标的分割，提出了一种鲁棒性较好的视频分割算法，该算法通过对图象序列中每连续3 帧图象进行对称差分，首先检测出目标的运动范围，然后通过对差分结构进行聚类分析来确定该帧图象中视频对象的个数，接着再利用在二值差分图象上收缩的活动轮廓，把视频对象的轮廓精确地包围起来，即得到该帧分割结果；最后利用光流法来对视频对象进行投注跟踪，修正，另外还利用多个图象序列对该方法进行了试验，实验结果表明，在静止背景下，该算法无论是对运动的单目标，还是对运动的多目标，均能较好地从静止背景中分离出来，即能得到理想的分割结果，故具有一定的鲁棒性和实用性。     

一种用于模块间解耦的对象访问模式

为了有效解决模块之间因共享数据而产生的交互耦合，提出了一种新的设计模式——注册仓模式。该模式封装了共享数据，避免了数据在各个使用者之间传递，分离了数据的提供者和使用者，实现了模块间一种简化的数据访问协议，降低了模块间的耦合度。理论和实践证明注册仓模式能良好地适用基于组件或模块的软件体系架构下面向对象的程序设计。     

中文非功能需求描述的识别与分类方法研究

非功能需求描述系统质量相关的属性,是软件设计决策的重要依据和评估标准.与功能需求的描述相比,非功能需求描述通常比较分散,且往往是隐含的.当采集到的需求原始描述内容较多时,逐一进行人工判别和整理需要耗费大量的时间和精力.针对中文自然语言描述的需求文本,提出了自动化的非功能需求识别和分类方法.其中,识别过程旨在从文本中提取出可能包含非功能需求的语句,尽可能地缩小人工检查的范围.分类过程则进一步将包含非功能需求的语句划分到性能、可靠性、可用性、安全性、可维护性这五大类非功能需求类型之中.分类训练和实验测试基于课题组工作项目整理的实验数据集进行,最终,基于一个工业界的实际应用案例数据,验证了方法的有效性.     

Knowledge based formation of re-configurable assembly cells

When developing assembly cells with highly complex modular structures, designers need to translate user requirements into a set of design rules and potential cell configurations. The success in matching user requirements to potential products is dependent on how well the functional and non-functional customer requirements can be understood and translated into cell features (design rules, processes and module types). This paper reports on a knowledge based methodology for forming customisable re-configurable assembly cells. The approach is based on matching user requirements to existing supplier knowledge in terms of design rules and principles, modules offered by different vendors, new emerging technologies and existing own and competitors’ products. The decision making includes requirements analysis, generating assembly processing alternatives and evaluating and selecting assembly modules and cells. The proposed approach aims to assist decision making in assembly system design by enabling users and suppliers to jointly participate in an interactive and iterative process of forming re-configurable assembly cells.