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| 3. |
- Broman, David, 1977-, et al.
(författare)
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Determining Over- and Under-Constrained Systems of Equations using Structural Constraint Delta
- 2006
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Ingår i: Proceedings of the 5th International Conference on Generative Programming and Component Engineering. - New York, NY, USA : ACM. ; , s. 151-160
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Konferensbidrag (refereegranskat)abstract
- Computer aided modeling and simulation of complex physical systems, using components from multiple application domains, such as electrical, mechanical, and hydraulic, have in recent years witnessed a significant growth of interest. In the last decade, equation-based object-oriented (EOO) modeling languages, (e.g. Modelica, gPROMS, and VHDL-AMS) based on acausal modeling using Differential Algebraic Equations (DAEs), have appeared. With such languages, it is possible to model physical systems at a high level of abstraction by using reusable components.A model in an EOO language needs to have the same number of equations as unknowns. A previously unsolved problem concerning this property is the efficient detection of over- or under-constrained models in the case of separately compiled models.This paper describes a novel technique to determine over- and under-constrained systems of equations in models, based on a concept called structural constraint delta. In many cases it is also possible to locate the source of the constraint-problem. Our approach makes use of static type checking and consists of a type inference algorithm. We have implemented it for a subset of the Modelica language, and successfully validated it on several examples.
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| 4. |
- Broman, David, 1977-, et al.
(författare)
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Types in the Modelica Language
- 2006
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Ingår i: Proceedings of the Fifth International Modelica Conference. ; , s. 303-315
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Konferensbidrag (refereegranskat)abstract
- Modelica is an object-oriented language designed for modeling and simulation of complex physical systems. To enable the possibility for an engineer to discover errors in a model, languages and compilers are making use of the concept of types and type checking. This paper gives an overview of the concept of types in the context of the Modelica language. Furthermore, a new concrete syntax for describing Modelica types is given as a starting point to formalize types in Modelica. Finally, it is concluded that the current state of the Modelica language specification is too informal and should in the long term be augmented by a formal definition.
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| 5. |
- Bunus, Peter, et al.
(författare)
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Automated static analysis of equation-based components
- 2004
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Ingår i: Simulation (San Diego, Calif.). - : SAGE Publications. - 0037-5497 .- 1741-3133. ; 80:7-8, s. 321-345
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Tidskriftsartikel (refereegranskat)abstract
- Mathematical modeling and the simulation of complex physical systems are emerging as key technologies in engineering. The availability of static analyzers and automatic debuggers for detecting structural and numerical inconsistencies in the simulation models is crucial. To address this need, the authors propose a methodology for detecting and repairing overconstrained and underconstrained situations based on graph-theoretical approaches. Components and equations that cause the irregularities are automatically isolated, and meaningful error messages for the user are elaborated. The authors have implemented the AMOEBA (Automatic Modelica Equation-Based Analyzer) environment to support the development and specification of correct equation-based simulation models by applying graph-theoretical approaches and semiautomatic debugging techniques. The implementation architecture and preliminary experiments with a prototype debugger integrated in the symbolic and numeric engine, ModSimPack, of the Modelica language compiler are presented and discussed.
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| 7. |
- Chen, W., et al.
(författare)
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A generic FMU interface for modelica
- 2011
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Ingår i: Proceedings of the 4th International Workshop on Equation-Based Object-Oriented Modeling Languages and Tools, EOOLT 2011. ; , s. 19-24
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Konferensbidrag (refereegranskat)abstract
- This paper discusses technical issues and implementation of a generic interface to import a Functional Mock-up Unit (FMU) into Modelica simulators, specifically the Open- Modelica environment. Whereas other approaches for importing the FMUs rely on functionality specific to the simulator environment, this approach tries to provide a generic Modelica interface for embedding an FMU to be imported into a Modelica model. In this way any FMU conforming to the Functional Mock-up Interface (FMI) for Model Exchange v1.0 Specification for model exchange from MODELISAR can be imported into any Modelica simulator. When importing an FMU into a model, the resulting Modelica model can be used just like any pure Modelica models. Hence, a better reusability and interoperability for both sides, namely the external models provided via FMI and the Modelica environment, are achieved.
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| 8. |
- Edelfeldt, S., et al.
(författare)
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Evaluation and comparison of models and modelling tools simulating nitrogen processes in treatment wetlands
- 2008
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Ingår i: Simulation (San Diego, Calif.). - : Elsevier BV. - 1569-190X .- 1878-1462. ; 16:1, s. 26-49
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, two ecological models of nitrogen processes in treatment wetlands have been evaluated and compared. These models were implemented, simulated, and visualized using the Modelica modelling and simulation language [P. Fritzson, Principles of Object-Oriented Modelling and Simulation with Modelica 2.1 (Wiley-IEEE Press, USA, 2004).] and an associated tool. The differences and similarities between the MathModelica Model Editor and three other ecological modelling tools have also been evaluated. The results show that the models can well be modelled and simulated in the MathModelica Model Editor, and that nitrogen decrease in a constructed treatment wetland should be described and simulated using the Nitrification/Denitrification model as this model has the highest overall quality score and provides a more variable environment. © 2007 Elsevier B.V. All rights reserved.
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| 10. |
- Fritzson, Peter, et al.
(författare)
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Equation-based object-oriented languages and tools : Report on the 2nd workshop EOOLT at ECOOP 2008
- 2009. - 1
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Ingår i: Object-Oriented Technology. - Berlin, Heidelberg : Springer Berlin/Heidelberg. - 3642020461 - 9783642020469 - 9783642020476 ; , s. 18-29
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- EOOLT2008 was the second edition of the ECOOP-EOOLT workshop. The workshop is intended to bring researchers associated with different equation-based object-oriented (EOO) modeling languages and different application areas making use of such languages together. The aim of the workshop is to explore common grounds and derive software design principles that may make future EOO modeling languages more robust, more versatile, and more widely accepted among the various stakeholders. At EOOLT2008, researchers with diverse backgrounds and needs came together to present and discuss fourteen different concept papers grouped into the four topic areas of integrated system modeling approaches; modeling for multiple applications; modeling language design, and equation handling, diagnosis, and modeling.
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