Electronic Communications of the EASST (European Association of Software Science and Technology)
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The Web Service Challenge - A review on Semantic Web Service Composition
Get PDFEvery year, contesters submit contributions to the Web Service Challenge (WSC) in order to determine which service composition system is the most efficient one. In this challenge, semantic composition tasks must be solved and the results delivered by the composers are checked for correctness. The time needed for the composition process is another important competition criterion.
After we had participated with great success in the 2006 and 2007 WSC, we were asked to manage the Web Service Challenge 2008. In this paper, we present the challenge task, the challenge rules, the document format used, and the results of this competition. We provide a summary over the past challenges and give first previews on the future developments planned for the Web Service Challenges to come
Towards a metric for Open Source Software Quality
Get PDFSoftware quality is more than just conformance to a set of requirements and represents many attributes related to each other that make up a piece of software. An important part of this measure depends on the underlying processes and methodologies used in the engineering of software. We present an early exposition towards a quality model for open source software (OSS). We describe some basic notions of quality for OSS and present a basic model, where quality notions consist of various factors that influence such quality. The purpose of this effort is ultimately to develop a quantitative metric for software quality
Analysis of Inconsistent Routing Components in Reactive Routing Protocols
Get PDFIn reactive routing protocols, additional routing information is often collected
to reduce the response time and the overhead of the future routing demands.
However, these protocols do not have any mechanism to refresh this routing information
and soon it become obsolete. Therefore, routing components based on this
prior-to-demand collected information are not consistent with the reactive nature
of the protocol. In this work, we have identified such inconsistent components in
AODV routing protocol and have analyzed their effect. Our simulation based analysis
has revealed that the presence and use of stale routing information degrades the
protocol performance. However, if the dependency of protocol operations on this
obsolete information is reduced, the protocol performs better in terms of overhead
and packet delivery ratio
Model-based Simulation of VoIP Network Reconfigurations using Graph Transformation Systems
Get PDFWe address the modelling and validation of P2P networks with
special attention for problems related to VoIP services, focusing particularly
on Skype. We use generalised stochastic graph transformation systems
and associated stochastic simulation techniques based on generalised semi-
Markov processes
Concurrent Design of Embedded Control Software
Get PDFEmbedded software design for mechatronic systems is becoming an increasingly time-consuming and error-prone task. In order to cope with the heterogeneity and complexity, a systematic model-driven design approach is needed, where several parts of the system can be designed concurrently. There is however a trade-off between concurrency efficiency and integration efficiency. In this paper, we present a case study on the development of the embedded control software for
a real-world mechatronic system in order to evaluate how we can integrate concurrent and largely independent designed embedded system software parts in an efficient way. The case study was executed using our embedded control system design
methodology which employs a concurrent systematic model-based design approach that ensures a concurrent design process, while it still allows a fast integration phase by using automatic code synthesis. The result was a predictable concurrently designed embedded software realization with a short integration time
Towards Logical Clocks in P2P-based MMVEs
Get PDFA crucial requirement for peer-to-peer-based Massively Multiuser Virtual
Environments (P2P-based MMVEs) is the accurate and reliable synchronization of
actions among the users (processes). To do so, clock synchronization protocols
can be used. In this paper we first analyze the usage of standard vector clocks for
this purpose and show their deficits (e.g. growing large). Then we present a novel
variation of vector clocks – pruned vector clocks – which overcome the deficits of
standard vector clocks and are therefore suited for their usage in MMVEs. The basic
idea of pruned vector clocks is to prune all entries in a vector clock, which are not
relevant at some point in time. We show, that with this approach vector clocks will
stay constant in size and still provide the necessarily synchronization among the
processes
Refactoring of Model Transformations
Get PDFModel-to-model transformations between visual languages are often defined by typed, attributed graph transformation systems. Here, the source and target languages of the model transformation are given by type graphs (or meta models),
and the relation between source and target model elements is captured by graph transformation rules. On the other hand, refactoring is a technique to improve the structure of a model in order to make it easier to comprehend, more maintainable
and amenable to change. Refactoring can be defined by graph transformation rules, too. In the context of model transformation, problems arise when models of the source language of a model transformation become subject to refactoring. It may well be the case that after the refactoring, the model transformation rules are no longer applicable because the refactoring induced structural changes in the models. In this paper, we consider a graph-transformation-based evolution of model transformations
which adapts the model transformation rules to the refactored models.
In the main result, we show that under suitable assumptions, the evolution leads to an adapted model transformation which is compatible with refactoring of the source and target models. In a small case study, we apply our techniques to a well-known
model transformation from statecharts to Petri nets
Open Source Certification and Educational Process
Get PDFThis paper discusses possibilities to benefit software engineering and computer sciences educational process from involving students in open source software certification activities. On the other hand the open source certification community can take advantages of this involvement if it cooperates with educational one. The situation is considered in the context of Russian higher institutes of education but the conclusions can be applicable to other institutes as well
