In this paper, we propose a means to enhance an architecture description language with a description of component behavior. A notation used for this purpose should be able to express the "interplay" ...on the component's interfaces and reflect step-by-step refinement of the component's specification during its design. In addition, the notation should be easy to comprehend and allow for formal reasoning about the correctness of the specification refinement and also about the correctness of an implementation in terms of whether it adheres to the specification. Targeting all these requirements together, the paper proposes employing behavior protocols which are based on a notation similar to regular expressions. As proof of the concept, the behavior protocols are used in the SOFA architecture description language at three levels: interface, frame, and architecture. Key achievements of this paper include the definitions of bounded component behavior and protocol conformance relation. Using these concepts, the designer can verify the adherence of a component's implementation to its specification at runtime, while the correctness of refining the specification can be verified at design time.
Reuse is one of the key benefits of components. It inherently means that the functionality of a component may be employed only partially. This triggers the issue whether all of the component's ...interfaces have to be really bound to the other components in its current environment (missing binding problem). Assuming each of the components is equipped by its behavior protocol (F. Plasil et al., 2002), we show that missing bindings can be statically identified via verification tools, in particular by employing the concept of bad activity error introduced in (J. Adamek et al., 2004).
The advantage of textual use-cases is that they can be easily understood by stakeholders and domain experts. However, since use-cases typically rely on a natural language, they cannot be directly ...subject to a formal verification. In this paper, we present the FOAM method which features simple user-definable annotations, inserted into a use-case to make its semantics more suitable for verification. Subsequently a model-checking tool verifies temporal invariants associated with the annotations. This way, FOAM allows for harnessing the benefits of model-checking while still keeping the use-cases understandable for non-experts.
Charged particles and photons have been measured in central Pb + Pb collisions at 158 A GeV in a common (eta-phi)-phase space region in the WA98 experiment at the CERN SPS. The measured distributions ...have been analyzed to quantify the frequency with which phase space regions of varying sizes have either small or large neutral pion fraction. The measured results are compared with VENUS model simulated events and with mixed events. Events with both large and small charged-neutral fluctuations are observed to occur more frequently than expected statistically, as deduced from mixed events, or as predicted by model simulations, with the difference becoming more prominent with decreasing size of the A Delta eta-Delta phi region. (C) 2011 Elsevier B.V. All rights reserved.
Measurements of direct photon production in p + Pb and p + C collisions at root(NN)-N-s = 17.4 GeV are presented. Upper limits on the direct photon yield as a function of p(T) are derived and ...compared to the results for Pb + Pb collisions at root(NN)-N-s = 17.3 GeV. The production of the eta meson, which is an important input to the direct photon signal extraction, has been determined in the eta -> 2 gamma channel for p + C collisions at root(NN)-N-s = 17.4 GeV. (c) 2012 Elsevier B.V. All rights reserved.
Measurements of direct photon production in p+Pb and p+C collisions at sNN=17.4 GeV are presented. Upper limits on the direct photon yield as a function of pT are derived and compared to the results ...for Pb+Pb collisions at sNN=17.3 GeV. The production of the η meson, which is an important input to the direct photon signal extraction, has been determined in the η→2γ channel for p+C collisions at sNN=17.4 GeV.
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