The method uses an intermediate model that acts as bridge between Pacritinib the annotated UML models and the analysis-oriented models. In particular, discrete time Markov process models can be derived for the computation of the service reliability.Finally, the work [28] proposes a model-to-model transformation technique to support the availability evaluation of railway control systems. The availability model is a repairable fault tree that is automatically generated from the UML models (use case, component, and state machine diagrams), properly annotated with MARTE and DAM extensions.8. Conclusion A standard specification framework is yet needed for dependability assessment of UML-based specifications. DAM is a step toward this goal, as it is a comprehensive approach attempting to unify a great number of efforts carried out by the researchers in the last decade.

Software quality includes a number of very different NFPs (e.g., security, performance, and dependability), which are often in conflict with each other [29]. In this context, the MARTE-DAM profile is a promising common framework for the specification of different NFPs in UML-based design. We envisage that a future research goal is to devise model transformation techniques that support a comprehensive analysis in presence of conflicting NFPs (e.g., performability, vulnerability, and survivability issues), in order to provide trade-off solutions to the software engineer. Acknowledgments This paper has been partially supported by Fundaci��n Arag��n I+D, by Spanish Projects TIN2011-24932 and DPI2010-20413 and by a Discovery grant from the Natural Sciences and Engineering Research Council of Canada (NSERC).

AppendixA. MARTE and DAM Profiles A.1. MARTE The ��UML Profile for Modeling and Analysis of Real-Time and Embedded systems�� [12] is an OMG standard profile that extends UML in a lightweight fashion (i.e. via the standard UML extension mechanism including stereotypes, tagged values, and constraints) and enables the specification of both quantitative and qualitative nonfunctional properties (NFP) in the form of annotations attached to UML model elements.The Value Specification Language (VSL), which is a part of MARTE, provides the ability to express NFP types (defined in the so called MARTE library), values of NFP types, as well as variables, constants, and expressions.

All of these are used by the modeler to assign values to tags, according to the VSL syntax (the annotations in Figure 2 show several examples). Tags of NFP types are characterized by several qualifiers: source defines the origin of the specification (such as required, assumed, predicted, and measured); statQ defines the type of a statistical measure (such as a maximum, Cilengitide minimum, or mean); unit indicates the measurement unit for a given NFP.