Auflistung P088 - NODe 2006 - GSEM 2006 nach Erscheinungsdatum
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- KonferenzbeitragThe role of reflective middleware in supporting flexible security policies(NODe 2006 – GSEM 2006, 2006) Xu, Na; Blair, Gordon S.; Myrvang, Per Harald; Stabell-Kulø, Tage; Grace, PaulNext generation middleware must support applications in the face of increasing diversity in interaction paradigms, end system types and network styles. Therefore, to secure applications, security policies must be configured and indeed reconfigured at runtime. In this paper, we propose an approach combining the openness of reflective middleware with the flexibility of programmable security to meet such demands. In particular, we build a security architecture based on the Gridkit reflective middleware platform and the Obol security protocol programming language. The paper then describes a case study that uses flexible policies in order to secure remote procedure calls and secure group communication. We also present the benefits of this approach in terms of flexibility, ease of use and extensibility.
- KonferenzbeitragModelling and solving QoS composition problem using DisCSP(NODe 2006 – GSEM 2006, 2006) Nguyen, Xuan Thang; Kowalczyk, Ryszard; Phan, Khoi AnhWeb services have emerged as a popular technology for integrating distributed applications. A Web service composition is a description of how different Web services can interoperate in order to perform more complex tasks. QoS for composite Web services has attracted interests from both research and industrial communities. In this paper, we propose an agent-based solution for the QoS composition problem using Distributed Constraint Satisfaction Problem (DisCSP) techniques. We show that by using the composition structures, local constraints can be constructed and used with DisCSP. We also present an enhancement of the Asynchronous Aggregate Search (AAS) algorithm to solve the problem and discuss our initial experiment in building a multi-agent system to prove the feasibility of our approach.
- KonferenzbeitragGSEE: A grid-enabled value-added service platform in NGN(NODe 2006 – GSEM 2006, 2006) Li, Li; Yang, FangchunGSEE - a grid-enabled value-added service platform in Next Generation Network (NGN) - is proposed to solve the performance problem with traditional service platform of NGN. The value-added services hosted by GSEE are wrapped into grid services. GSEE and other nodes with spare processing capability are organized into virtual organization (VO). A task scheduling algorithm is proposed to overcome the performance bottleneck problem when system gets overload by leveraging existing resources in the same VO. GSEE is modeled by Stochastic Petri Net (SPN) in this paper. And simulation experiment is done based on this model, with the help of SPNP (stochastic Petri net package) to test the performance of GSEE. The simulation result verifies GSEE can really improve system performance.
- KonferenzbeitragStatic architecture evaluation of open source reuse candidates(NODe 2006 – GSEM 2006, 2006) Knodel, Jens; Muthig, Dirk; Naab, MatthiasOpen source software systems provide a variety of field-tested components offering software development organizations the potential to reuse and adapt such components for their own purposes. The main challenge before achieving the reuse benefits is to acquire a thorough understanding of open source software systems (i.e., the reuse candidates) in order to reason about alternative solutions, to learn about the points where to adapt the system and eventually to decide whether or not to invest into reuse. Manually analyzing even small systems is a time-consuming, complex and costly task. In this paper we present a case study where we analyzed the Apache Tomcat web server supported by a software architecture visualization and evaluation tool and demonstrate how the tool facilitated our comprehension tasks to learn about the architectural means and concepts.
- KonferenzbeitragA reusable architecture with product line technique applied to context sensitive service(NODe 2006 – GSEM 2006, 2006) Lee, Seojeong; Hwang, S. W.; Kim, G. H.; Ryu, G. S.; Choi, MisookIn ubiquitous environments, the content adaptable services can be dynamically provided to adapt the frequent changes of contexts. These services have common things that the kinds of context factors are limited to ubiquitous environment, though the contexts are flexible. To reuse service architecture can be reasonable for effective adaptable service. In this paper, we propose a reusable architecture with product line techniques for content adaptable applications in ubiquitous environment. It can describe reusable points for service and optimization policies. Description of reusable points is to define variation points and their variants and to find out the dependencies between them. Optimization policies are to build the variant selection strategies. These can accomplish to define the decision model based on content adaptable service, and to help the reuse more effective.
- KonferenzbeitragGDT: A toolkit for grid service development(NODe 2006 – GSEM 2006, 2006) Friese, Thomas; Smith, Matthew; Freisleben, BerndThe inherent complexity of Grid application development is an obstacle to the widespread adoption of service oriented Grid technology. In this paper, a software development environment for service oriented Grid applications integrated into the Eclipse platform is presented. Its design is based on model-driven software development principles, allowing domain experts to rapidly develop Grid applications by hiding the complexities of Grid middleware. The functionality of the three main components supporting service creation, process creation and interactive debugging are presented, and implementation issues is discussed.
- KonferenzbeitragPatterns for re-usable aspects in object teams(NODe 2006 – GSEM 2006, 2006) Sokenou, Dehla; Mehner, Katharina; Herrmann, Stephan; Sudhof, HenryAspect-oriented software development still lacks practical evidence. While aspects are claimed to be useful in adapting existing applications there is also first evidence that they might themselves be re-usable. We present results from two case studies with the aspect-oriented programming language ObjectTeams/Java that investigate the re-usability of aspects in developing a security framework. During the development of the framework we have identified patterns for re-usable aspects that increase the flexibility when applying a framework to a given application.
- KonferenzbeitragAvoiding infinite recursion with stratified aspects(NODe 2006 – GSEM 2006, 2006) Bodden, Eric; Forster, Florian; Steimann, FriedrichInfinite recursion is a known problem of aspect-oriented programming with AspectJ: if no special precautions are taken, aspects advising aspects can easily and unintentionally advise themselves. We present a compiler for an extension of the AspectJ programming language that avoids self reference by associating aspects with levels, and by automatically restricting the scope of pointcuts used by an aspect to join points of lower levels. We report on a case study using our language extension, and provide numbers of the changes necessary for migrating existing applications to it. Our results suggest that we can make programming with AspectJ simpler and safer, without restricting its expressive power unduly.
- KonferenzbeitragExplicit high-level rules for the customization of web services management(NODe 2006 – GSEM 2006, 2006) Cibrán, María Agustina; D'Hondt, MajaCurrent Web Services integration approaches fail at supporting a highly flexible service selection and management. To overcome these problems, the Web Services Management Layer was proposed in previous work. However, this layer presents some limitations due to the implicit representation of service criteria that guide its customization. In this paper we propose externalizing these criteria as highlevel business rules. Moreover, the specification of new unanticipated business rules is also supported. We do this by employing a high-level business rule language proposed in previous work. We show how this rule language can be used to customize the WSML, enhancing flexibility. The originality of our approach is the application of a general-purpose business rule language to the domain of Web Services management.
- KonferenzbeitragPath expression pointcuts: Abstracting over non-local object relationships in aspect-oriented languages(NODe 2006 – GSEM 2006, 2006) Al-Mansari, Mohammed; Hanenberg, StefanIn aspect-oriented programming, aspects require access to join point information for selecting join points within pointcuts as well as for specifying aspect-specific behavior at such join points within advice. Unfortunately, aspectoriented systems typically provide only local information about join points, i.e. information that is directly accessible from the execution context at the corresponding join points like the target object within a method call. However, there are many situations where the needed information is not directly available and relies on object information that is non-local concerning the execution context at the corresponding join points. As a consequence, developers are forced to specify a number of work-arounds – pointcuts and advice that neither reflect on the conceptual join point selection nor purely on the conceptual aspect behavior. In this paper, we show recurring situations in which "local" join point information is not sufficient for specifying aspects. We propose so called "path expression pointcuts" that permit to abstract over (non-local) object-relationships within pointcuts – and show that this overcomes the problem.