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Towards an aspect weaving BPEL engine
This position paper proposes the use of dynamic aspects and
the visitor design pattern to obtain a highly configurable and
extensible BPEL engine. Using these two techniques, the
core of this infrastructural software can be customised to
meet new requirements and add features such as debugging,
execution monitoring, or changing to another Web Service
selection policy. Additionally, it can easily be extended to
cope with customer-specific BPEL extensions. We propose
the use of dynamic aspects not only on the engine itself
but also on the workflow in order to tackle the problems of
Web Service hot deployment and hot fixes to long running
processes. In this way, composing aWeb Service "on-the-fly"
means weaving its choreography interface into the workflow
A trustworthy mobile agent infrastructure for network management
Despite several advantages inherent in mobile-agent-based approaches to network management as compared to traditional SNMP-based approaches, industry is reluctant to adopt the mobile agent paradigm as a replacement for the existing manager-agent model; the management community requires an evolutionary, rather than a revolutionary, use of mobile agents. Furthermore, security for distributed management is a major concern; agent-based management systems inherit the security risks of mobile agents. We have developed a Java-based mobile agent infrastructure for network management that enables the safe integration of mobile agents with the SNMP protocol. The security of the system has been evaluated under agent to agent-platform and agent to agent attacks and has proved trustworthy in the performance of network management tasks
A Mobile Computing Architecture for Numerical Simulation
The domain of numerical simulation is a place where the parallelization of
numerical code is common. The definition of a numerical context means the
configuration of resources such as memory, processor load and communication
graph, with an evolving feature: the resources availability. A feature is often
missing: the adaptability. It is not predictable and the adaptable aspect is
essential. Without calling into question these implementations of these codes,
we create an adaptive use of these implementations. Because the execution has
to be driven by the availability of main resources, the components of a numeric
computation have to react when their context changes. This paper offers a new
architecture, a mobile computing architecture, based on mobile agents and
JavaSpace. At the end of this paper, we apply our architecture to several case
studies and obtain our first results
Efficient Dynamic Access Analysis Using JavaScript Proxies
JSConTest introduced the notions of effect monitoring and dynamic effect
inference for JavaScript. It enables the description of effects with path
specifications resembling regular expressions. It is implemented by an offline
source code transformation.
To overcome the limitations of the JSConTest implementation, we redesigned
and reimplemented effect monitoring by taking advantange of JavaScript proxies.
Our new design avoids all drawbacks of the prior implementation. It guarantees
full interposition; it is not restricted to a subset of JavaScript; it is
self-maintaining; and its scalability to large programs is significantly better
than with JSConTest.
The improved scalability has two sources. First, the reimplementation is
significantly faster than the original, transformation-based implementation.
Second, the reimplementation relies on the fly-weight pattern and on trace
reduction to conserve memory. Only the combination of these techniques enables
monitoring and inference for large programs.Comment: Technical Repor
Two ways to Grid: the contribution of Open Grid Services Architecture (OGSA) mechanisms to service-centric and resource-centric lifecycles
Service Oriented Architectures (SOAs) support service lifecycle tasks, including Development, Deployment, Discovery and Use. We observe that there are two disparate ways to use Grid SOAs such as the Open Grid Services Architecture (OGSA) as exemplified in the Globus Toolkit (GT3/4). One is a traditional enterprise SOA use where end-user services are developed, deployed and resourced behind firewalls, for use by external consumers: a service-centric (or âfirst-orderâ) approach. The other supports end-user development, deployment, and resourcing of applications across organizations via the use of execution and resource management services: A Resource-centric (or âsecond-orderâ) approach. We analyze and compare the two approaches using a combination of empirical experiments and an architectural evaluation methodology (scenario, mechanism, and quality attributes) to reveal common and distinct strengths and weaknesses. The impact of potential improvements (which are likely to be manifested by GT4) is estimated, and opportunities for alternative architectures and technologies explored. We conclude by investigating if the two approaches can be converged or combined, and if they are compatible on shared resources
Implementing a distributed mobile calculus using the IMC framework
In the last decade, many calculi for modelling distributed mobile code have been proposed. To assess their merits and encourage use, implementations of the calculi have often been proposed. These implementations usually consist of a limited part dealing with mechanisms that are specific of the proposed calculus and of a significantly larger part handling recurrent mechanisms that are common to many calculi. Nevertheless, also the "classic" parts are often re-implemented from scratch. In this paper we show how to implement a well established representative of the family of mobile calculi, the distributed [pi]-calculus, by using a Java middleware (called IMC - Implementing Mobile Calculi) where recurrent mechanisms of distributed and mobile systems are already implemented. By means of the case study, we illustrate a methodology to accelerate the development of prototype implementations while concentrating only on the features that are specific of the calculus under consideration and relying on the common framework for all the recurrent mechanisms like network connections, code mobility, name handling, etc
Analysis of current middleware used in peer-to-peer and grid implementations for enhancement by catallactic mechanisms
This deliverable describes the work done in task 3.1, Middleware analysis: Analysis of current middleware used in peer-to-peer and grid implementations for enhancement by catallactic mechanisms from work package 3, Middleware Implementation. The document is divided in four parts: The introduction with application scenarios and middleware requirements, Catnets middleware architecture, evaluation of existing middleware toolkits, and conclusions. -- Die Arbeit definiert Anforderungen an Grid und Peer-to-Peer Middleware Architekturen und analysiert diese auf ihre Eignung fĂŒr die prototypische Umsetzung der Katallaxie. Eine Middleware-Architektur fĂŒr die Umsetzung der Katallaxie in Application Layer Netzwerken wird vorgestellt.Grid Computing
Concepts and their Use for Modelling Objects and References in Programming Languages
In the paper a new programming construct, called concept, is introduced.
Concept is pair of two classes: a reference class and an object class.
Instances of the reference classes are passed-by-value and are intended to
represent objects. Instances of the object class are passed-by-reference. An
approach to programming where concepts are used instead of classes is called
concept-oriented programming (CoP). In CoP objects are represented and accessed
indirectly by means of references. The structure of concepts describes a
hierarchical space with a virtual address system. The paper describes this new
approach to programming including such mechanisms as reference resolution,
complex references, method interception, dual methods, life-cycle management
inheritance and polymorphism.Comment: 43 pages. Related papers: http://conceptoriented.com
JooFlux: Hijacking Java 7 InvokeDynamic To Support Live Code Modifications
Changing functional and non-functional software implementation at runtime is
useful and even sometimes critical both in development and production
environments. JooFlux is a JVM agent that allows both the dynamic replacement
of method implementations and the application of aspect advices. It works by
doing bytecode transformation to take advantage of the new invokedynamic
instruction added in Java SE 7 to help implementing dynamic languages for the
JVM. JooFlux can be managed using a JMX agent so as to operate dynamic
modifications at runtime, without resorting to a dedicated domain-specific
language. We compared JooFlux with existing AOP platforms and dynamic
languages. Results demonstrate that JooFlux performances are close to the Java
ones --- with most of the time a marginal overhead, and sometimes a gain ---
where AOP platforms and dynamic languages present significant overheads. This
paves the way for interesting future evolutions and applications of JooFlux
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