Computing and Information Systems - Research Publications
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ItemUnveiling Hidden Unstructured Regions in Process Models(SPRINGER-VERLAG BERLIN, 2009-01-01)Process models define allowed process execution scenarios. The models are usually depicted as directed graphs, with gateway nodes regulating the control flow routing logic and with edges specifying the execution order constraints between tasks. While arbitrarily structured control flow patterns in process models complicate model analysis, they also permit creativity and full expressiveness when capturing non-trivial process scenarios. This paper gives a classification of arbitrarily structured process models based on the hierarchical process model decomposition technique. We identify a structural class of models consisting of block structured patterns which, when combined, define complex execution scenarios spanning across the individual patterns. We show that complex behavior can be localized by examining structural relations of loops in hidden unstructured regions of control flow. The correctness of the behavior of process models within these regions can be validated in linear time. These observations allow us to suggest techniques for transforming hidden unstructured regions into block-structured ones.
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ItemOn application of structural decomposition for process model abstraction(Springer Verlag, 2009-12-01)Real world business process models may consist of hundreds of elements and have sophisticated structure. Although there are tasks where such models are valuable and appreciated, in general complexity has a negative influence on model comprehension and analysis. Thus, means for managing the complexity of process models are needed. One approach is abstraction of business process models - creation of a process model which preserves the main features of the initial elaborate process model, but leaves out insignificant details. In this paper we study the structural aspects of process model abstraction and introduce an abstraction approach based on process structure trees (PST). The developed approach assures that the abstracted process model preserves the ordering constraints of the initial model. It surpasses pattern-based process model abstraction approaches, allowing to handle graph-structured process models of arbitrary structure. We also provide an evaluation of the proposed approach.
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ItemHypergraph-Based Modeling of Ad-Hoc Business Processes(SPRINGER-VERLAG BERLIN, 2009-01-01)Process models are usually depicted as directed graphs, with nodes representing activities and directed edges control flow. While structured processes with pre-defined control flow have been studied in detail, flexible processes including ad-hoc activities need further investigation. This paper presents flexible process graph, a novel approach to model processes in the context of dynamic environment and adaptive process participants’ behavior. The approach allows defining execution constraints, which are more restrictive than traditional ad-hoc processes and less restrictive than traditional control flow, thereby balancing structured control flow with unstructured ad-hoc activities. Flexible process graph focuses on what can be done to perform a process. Process participants’ routing decisions are based on the current process state. As a formal grounding, the approach uses hypergraphs, where each edge can associate any number of nodes. Hypergraphs are used to define execution semantics of processes formally. We provide a process scenario to motivate and illustrate the approach.
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ItemThe Triconnected Abstraction of Process Models(SPRINGER-VERLAG BERLIN, 2009-01-01)Companies use business process models to represent their working procedures in order to deploy services to markets, to analyze them, and to improve upon them. Competitive markets necessitate complex procedures, which lead to large process specifications with sophisticated structures. Real world process models can often incorporate hundreds of modeling constructs. While a large degree of detail complicates the comprehension of the processes, it is essential to many analysis tasks. This paper presents a technique to abstract, i.e., to simplify process models. Given a detailed model, we introduce abstraction rules which generalize process fragments in order to bring the model to a higher abstraction level. The approach is suited for the abstraction of large process specifications in order to aid model comprehension as well as decomposing problems of process model analysis. The work is based on process structure trees that have recently been introduced to the field of business process management.
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ItemAn argumentation-based interpreter for Golog programs( 2009)This paper presents an argumentation-based interpreter for Golog programs. Traditional Golog interpreters are not designed to find the most preferred executions of a program from the perspective of an agent. Existing techniques developed to discover these executions are limited in terms of how the preferences of an agent can be expressed, and the variety of preference types that can be used to guide search for a solution. The presented work combines the use of argumentation to compare executions relative to a set of general comparison principles, and the theory behind best first search to reduce the cost of the search process. To the best of our knowledge this is the first work to integrate argumentation and the interpretation of Golog programs, and to use argumentation as a tool for best first search.
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ItemA conceptual framework for assessing interaction quality in online discussion forums(ASCILITE, 2009-12-01)
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ItemVisualization of clusters in very large rectangular dissimilarity data(IEEE, 2009-06-05)
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ItemA Privacy Preserving E-Payment Scheme(SPRINGER-VERLAG BERLIN, 2009)
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ItemOpportunistic Sampling in Wireless Sensor Networks(ACM, 2009)In an active WSN where user queries are regularly processed, a significant proportion of nodes relay and overhear data generated by other nodes in the network. In this paper, we propose to exploit this mode of data communication towards a gradual buildup of global knowledge. We show that by harnessing the multihop and multipath communication advantages, only a few user queries in a WSN can lead to an accumulation of accurate global knowledge at node level. This global knowledge can greatly improve numerous WSN applications when used in data validation, event detection, and query optimization.
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ItemRoleVAT: Visual Assessment of Practical Need for Role Based Access Control(IEEE COMPUTER SOC, 2009)