Software Science (SwS) Research Publications

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Marija Bjekovic. ArchiMetal case study. Technical report: ICIS-R12004, May, Radboud University Nijmegen, 2012, Technical Note.

Enterprise architecture (EA) is defined as a coherent whole of principles, methods, and models that are used in design and realisation of an enterpriseā??s organisational structure, business processes, information systems, and infrastructure. This study illustrates the usefulness of EA instruments, in particular ArchiMate 1.0 modelling language, for the analysis and transformation of a fictitious company from metallurgic industry named ArchiMetal.

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Martijn Hendriks, and F.W. Vaandrager. Reconstructing Critical Paths from Execution Traces. Technical report: ICIS-R12007, December, Radboud University Nijmegen, 2012.

We consider the problem of constructing critical paths from incomplete information. In general, a directed acyclic graph of tasks with their execution times (i.e., a task graph) is necessary to extract critical paths. We assume, however, that only the set of tasks, and their start and end times are known, e.g., an execution trace in the form of a Gantt chart. This information can be extracted from real machines or from the output of analysis tools, whereas extraction of the exact task graph often is problematic due to imperative modeling formalisms and complicated platform semantics (resource allocation, varying execution speeds). We show that, based on start and end times only, an over-approximation of the critical paths of an unknown task graph can be extracted nevertheless. Furthermore, this approach is generalized to deal with ``noisy`` execution traces of real machines in which control overhead is present. Finally, we discuss various methods to deal with false positives, and apply our approach to a complex industrial case study.

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David N. Jansen, Flemming Nielson, and Lijun Zhang. Belief bisimulation for hidden Markov models: logical characterisation and decision algorithm. Technical report: ICIS-R12002, February, Radboud University Nijmegen, 2012.

This paper establishes connections between logical equivalences and bisimulation relations for hidden Markov models (HMM). Both standard and belief state bisimulations are considered. We also present decision algorithms for the bisimilarities. For standard bisimilarity, an extension of the usual partition refinement algorithm is enough. Belief bisimilarity, being a relation on the continuous space of belief states, cannot be described directly. Instead, we show how to generate a linear equation system in time cubic in the number of states.

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S. Michels, M. Velikova, A.J. Hommersom, and P.J.F. Lucas. A Probabilistic Logic-based Model for Fusing Attribute Information of Objects Under Surveillance. Technical report: ICIS-R12006, December, Radboud University Nijmegen, 2012.

The goal of surveillance is to detect or predict certain events, like accidents or illegal activities, by continuously monitoring the position and behaviour of objects of interest. The monitoring requires the collection of information from various and heterogeneous sources. The sheer amount of information leads to information overload of human operators. Additionally, for humans it is very hard to reason about uncertain information in a consistent, unbiased way. We developed a framework to fuse information about intrinsic properties and intentions of objects under surveillance to support human surveillance operators. The framework is based on a probabilistic logic. We show how our approach can be applied to build a model for maritime surveillance by adding domain specific knowledge to the general framework and experimentally show that our model can correct for errors in information transmitted by simulated vessels by fusing this information with information from other sources. To our knowledge this is one of the very few real-world applications of probabilistic logics in a real-world setting.

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