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Three multimedia models used at hazardous and radioactive waste sites
Multimedia models are used commonly in the initial phases of the remediation process where technical interest is focused on determining the relative importance of various exposure pathways. This report provides an approach for evaluating and critically reviewing the capabilities of multimedia models. This study focused on three specific models MEPAS Version 3.0, MMSOILS Version 2.2, and PRESTO-EPA-CPG Version 2.0. These models evaluate the transport and fate of contaminants from source to receptor through more than a single pathway. The presence of radioactive and mixed wastes at a site poses special problems. Hence, in this report, restrictions associated with the selection and application of multimedia models for sites contaminated with radioactive and mixed wastes are highlighted. This report begins with a brief introduction to the concept of multimedia modeling, followed by an overview of the three models. The remaining chapters present more technical discussions of the issues associated with each compartment and their direct application to the specific models. In these analyses, the following components are discussed: source term; air transport; ground water transport; overland flow, runoff, and surface water transport; food chain modeling; exposure assessment; dosimetry/risk assessment; uncertainty; default parameters. The report concludes with a description of evolving updates to the model; these descriptions were provided by the model developers
On formalizing UML with high-level Petri nets
Abstract. Object-oriented methodologies are increasingly used in software development. Despite the proposal of several formally based models, current object-oriented practice is still dominated by informal methodologies, like Booch, OMT, and UML. Unfortunately, the lack of dynamic semantics of such methodologies limits the possibility of early analysis of specifications. This paper indicates the feasibility of ascribing formal semantics to UML by defining translation rules that automatically map UML specifications to high-level Petri nets. This paper illustrates the method through the hurried philosophers problem, that is first specified by using (a subset of) UML, and then mapped onto high-level Petri nets. The paper indicates how UML specifications can be verified by discussing properties of the hurried philosophers problem that can be verified on the derived highlevel Petri net.