Enabling the Collaborative Definition of DSMLs

International audienceSoftware development processes are collaborative in nature. Neglecting the key role of end-users leads to software that does not satisfy their needs. This collaboration becomes specially important when creating Domain-Specific Modeling Languages (DSMLs), which are (modeling) languages specifically designed to carry out the tasks of a particular domain. While end-users are actually the experts of the domain for which a DSML is developed, their participation in the DSML specification process is still rather limited nowadays. In this paper we propose a more community-aware language development process by enabling the active participation of all community members (both developers and end-users of the DSML) from the very beginning. Our proposal is based on a DSML itself, called Collaboro, which allows representing change proposals on the DSML design and discussing (and tracing back) possible solutions, comments and decisions arisen during the collaboration

Model Checking Probabilistic Real-Time Properties for Service-Oriented Systems with Service Level Agreements

The assurance of quality of service properties is an important aspect of service-oriented software engineering. Notations for so-called service level agreements (SLAs), such as the Web Service Level Agreement (WSLA) language, provide a formal syntax to specify such assurances in terms of (legally binding) contracts between a service provider and a customer. On the other hand, formal methods for verification of probabilistic real-time behavior have reached a level of expressiveness and efficiency which allows to apply them in real-world scenarios. In this paper, we suggest to employ the recently introduced model of Interval Probabilistic Timed Automata (IPTA) for formal verification of QoS properties of service-oriented systems. Specifically, we show that IPTA in contrast to Probabilistic Timed Automata (PTA) are able to capture the guarantees specified in SLAs directly. A particular challenge in the analysis of IPTA is the fact that their naive semantics usually yields an infinite set of states and infinitely-branching transitions. However, using symbolic representations, IPTA can be analyzed rather efficiently. We have developed the first implementation of an IPTA model checker by extending the PRISM tool and show that model checking IPTA is only slightly more expensive than model checking comparable PTA.Comment: In Proceedings INFINITY 2011, arXiv:1111.267

Requirements Engineering

Requirements Engineering (RE) aims to ensure that systems meet the needs of their stakeholders including users, sponsors, and customers. Often consid- ered as one of the earliest activities in software engineering, it has developed into a set of activities that touch almost every step of the software development process. In this chapter, we reflect on how the need for RE was first recognised and how its foundational concepts were developed. We present the seminal papers on four main activities of the RE process, namely (i) elicitation, (ii) modelling & analysis, (iii) as- surance, and (iv) management & evolution. We also discuss some current research challenges in the area, including security requirements engineering as well as RE for mobile and ubiquitous computing. Finally, we identify some open challenges and research gaps that require further exploration

On the behaviour of the (e, 3e) total cross section for helium at high and intermediate energies

Applying the animated beam method the total cross sections (TCS) for double ionization (DI) of helium by electrons are measured in the collision energy region from threshold to 3 keV. The TCS for the same process are calculated at intermediate and high incident energies in the first Born approximation (FBA). The radial and angular correlations between the bound electrons and repulsion between the ejected electrons are accounted. In order to go beyond the FBA the scattered electron is considered as a particle being in the Coulomb field of the nucleus, the charge of which is screened by the ejected electrons. On the basis of the obtained results some conclusions concerning the behaviour of the TCS in the intermediate and high-energy regions are drawn

Electron-impact dissociative ionization of the molecular ion HDO+: A global view

We present a combined experimental and theoretical study of the fragmentation of HDO2+ molecular ions produced by electron-impact ionization of HDO+ in the collision energy range 20–2500 eV. Experimental absolute partial inclusive cross sections for the production of OD+, OH+, and O+ are reported and compared successfully to theoretical predictions. Ab initio methods are used to calculate the electron-impact ionization cross sections of the cationic ground state and first excited state leading to the first seven dicationic states. Dissociation probabilities of each channel are obtained by performing classical molecular dynamics on fitted dicationic potential energy surfaces. The predictive character of the theoretical modeling allows us to estimate that the nonmeasured dissociation channel giving a neutral oxygen atom contributes to 30% of the total ionization cross section. The isotopic ratio OD+/OH+ educed from the experiment is (3.1 ± 0.2) on average, constant in the 30–2500 eV energy range. The calculated isotopic ratio is found to be strongly dependent on the vibrational excitation of the target. Good agreement with the experimental value is obtained for a vibrational excitation corresponding to a temperature of about 2500 K, which is compatible with typical characteristics of electron cyclotron resonance (ECR) ion sources