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Saldamli, Levon
Publications (10 of 12) Show all publications
Fritzson, P., Pop, A. D., Lundvall, H., Aronsson, P., Nyström, K., Saldamli, L., . . . Sandholm, A. (2006). OpenModelica - A Free Open-Source Environment for System Modeling, Simulation, and Teaching. In: Proceedings of the2006 IEEE International Conference on Control Applications (CCA)2006 IEEE Conference on Computer-Aided Control Systems Design (CACSD)2006 IEEE International Symposium on Intelligent Control (ISIC): . Paper presented at IEEE International Conference on Control Applications, IEEE International Symposium on Computer-Aided, Control Systems Design, IEEE International Symposium on Intelligent Control, October 4-6, 2006, Munich, Germany (pp. 1588-1595). Munich, Germany: IEEE
Open this publication in new window or tab >>OpenModelica - A Free Open-Source Environment for System Modeling, Simulation, and Teaching
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2006 (English)In: Proceedings of the2006 IEEE International Conference on Control Applications (CCA)2006 IEEE Conference on Computer-Aided Control Systems Design (CACSD)2006 IEEE International Symposium on Intelligent Control (ISIC), Munich, Germany: IEEE , 2006, p. 1588-1595Conference paper, Published paper (Refereed)
Abstract [en]

Modelica is a modern, strongly typed, declarative, and object-oriented language for modeling and simulation of complex systems. This paper gives a quick overview of some aspects of the OpenModelica environment - an open-source environment for modeling, simulation, and development of Modelica applications. An introduction of the objectives of the environment is given, an overview of the architecture is outlined and a number of examples are illustrated.   

Place, publisher, year, edition, pages
Munich, Germany: IEEE, 2006
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-35788 (URN)10.1109/CACSD-CCA-ISIC.2006.4776878 (DOI)28586 (Local ID)0-7803-9797-5 (ISBN)0-7803-9797-5 (ISBN)28586 (Archive number)28586 (OAI)
Conference
IEEE International Conference on Control Applications, IEEE International Symposium on Computer-Aided, Control Systems Design, IEEE International Symposium on Intelligent Control, October 4-6, 2006, Munich, Germany
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2018-01-13
Saldamli, L. (2006). PDEModelica – A High-Level Language for Modeling with Partial Differential Equations. (Doctoral dissertation). : Institutionen för datavetenskap
Open this publication in new window or tab >>PDEModelica – A High-Level Language for Modeling with Partial Differential Equations
2006 (English)Doctoral thesis, monograph (Other academic)
Abstract [en]

This thesis describes work on a new high-level mathematical modeling language and framework called PDEModelica for modeling with partial differential equations. It is an extension to the current Modelica modeling language for object-oriented, equation-based modeling based on differential and algebraic equations. The language extensions and the framework presented in this thesis are consistent with the concepts of Modelica while adding support for partial differential equations and space-distributed variables called fields.

The specification of a partial differential equation problem consists of three parts: 1) the description of the definition domain, i.e., the geometric region where the equations are defined, 2) the initial and boundary conditions, and 3) the actual equations. The known and unknown distributed variables in the equation are represented by field variables in PDEModelica. Domains are defined by a geometric description of their boundaries. Equations may use the Modelica derivative operator extended with support for partial derivatives, or vector differential operators such as divergence and gradient, which can be defined for general curvilinear coordinates based on coordinate system definitions.

The PDEModelica system also allows the partial differential equation models to be defined using a coefficient-based approach, where PDE models from a library are instantiated with different parameter values. Such a library contains both continuous and discrete representations of the PDE model. The user can instantiate the continuous parts and define the parameters, and the discrete parts containing the equations are automatically instantiated and used to solve the PDE problem numerically.

Compared to most earlier work in the area of mathematical modeling languages supporting PDEs, this work provides a modern object-oriented

component-based approach to modeling with PDEs, including general support for hierarchical modeling, and for general, complex geometries. It is possible to separate the geometry definition from the model definition, which allows geometries to be defined separately, collected into libraries, and reused in new models. It is also possible to separate the analytical continuous model description from the chosen discretization and numerical solution methods. This allows the model description to be reused, independent of different numerical solution approaches.

The PDEModelica field concept allows general declaration of spatially distributed variables. Compared to most other approaches, the field concept described in this work affords a clearer abstraction and defines a new type of variable. Arrays of such field variables can be defined in the same way as arrays of regular, scalar variables. The PDEModelica language supports a clear, mathematical syntax that can be used both for equations referring to fields and explicit domain specifications, used for example to specify boundary conditions. Hierarchical modeling and decomposition is integrated with a general connection concept, which allows connections between ODE/DAE and PDE based models.

The implementation of a Modelica library needed for PDEModelica and a prototype implementation of field variables are also described in the thesis. The PDEModelica library contains internal and external solver implementations, and uses external software for mesh generation, requisite for numerical solution of the PDEs. Finally, some examples modeled with PDEModelica and solved using these implementations are presented.

Place, publisher, year, edition, pages
Institutionen för datavetenskap, 2006. p. 163
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1016
Series
Keywords
mathematical modeling, PDEModelica, Modelica, object-oriented modeling, equation-based modeling, declarative modeling, high-level modeling languages, mathematical modeling languages
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-7281 (URN)91-85523-84-4 (ISBN)
Public defence
2006-05-15, Alan Turing, Hus E, Campus Valla, Linköpings universitet, Linköping, 13:15 (English)
Opponent
Supervisors
Available from: 2006-09-06 Created: 2006-09-06 Last updated: 2018-01-13
Saldamli, L., Bachmann, L., Wiesmann, B. & Fritzson, P. (2005). A Framework for Describing and Solving PDE Models in Modelica. In: : . Paper presented at Modelica2005, the 4th International Modelica Conference,2005.
Open this publication in new window or tab >>A Framework for Describing and Solving PDE Models in Modelica
2005 (English)Conference paper, Published paper (Other academic)
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-23101 (URN)2498 (Local ID)2498 (Archive number)2498 (OAI)
Conference
Modelica2005, the 4th International Modelica Conference,2005
Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2018-01-13
Fritzson, P., Aronsson, P., Lundvall, H., Nyström, K., Pop, A., Saldamli, L. & Broman, D. (2005). The OpenModelica Modeling, Simulation, and Development Environment. In: : . Paper presented at 46th Conference on Simulation and Modelling of the Scandinavian Simulation Society (SIMS2005), Trondheim, Norway, October 13-14, 2005.
Open this publication in new window or tab >>The OpenModelica Modeling, Simulation, and Development Environment
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2005 (English)Conference paper, Published paper (Refereed)
Abstract [en]

Modelica is a modern, strongly typed, declarative, and object-oriented language for modeling and simulation of complex systems. This paper gives a quick overview of some aspects of the OpenModelica environment – an open-source environment for modeling, simulation, and development of Modelica applications. An introduction of the objectives of the environment is given, an overview of the architecture is outlined and a number of examples are illustrated.

National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-110211 (URN)
Conference
46th Conference on Simulation and Modelling of the Scandinavian Simulation Society (SIMS2005), Trondheim, Norway, October 13-14, 2005
Available from: 2014-09-04 Created: 2014-09-04 Last updated: 2014-10-20Bibliographically approved
Saldamli, L. & Fritzson, P. (2004). Field Type and Field Constructor in Modelica. In: : . Paper presented at SIMS 2004, the 45th Conference on Simulation and Modellin,2004.
Open this publication in new window or tab >>Field Type and Field Constructor in Modelica
2004 (English)Conference paper, Published paper (Other academic)
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-23099 (URN)2496 (Local ID)2496 (Archive number)2496 (OAI)
Conference
SIMS 2004, the 45th Conference on Simulation and Modellin,2004
Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2018-01-13
Aronsson, P., Fritzson, P., Saldamli, L., Bunus, P. & Nyström, K. (2003). Meta Programming and Function Overloading in OpenModelica. In: : . Paper presented at Proceedings of the 3rd International Modelica Conference (November 3-4, Linköping, Sweden).
Open this publication in new window or tab >>Meta Programming and Function Overloading in OpenModelica
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2003 (English)Conference paper, Published paper (Refereed)
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-62115 (URN)
Conference
Proceedings of the 3rd International Modelica Conference (November 3-4, Linköping, Sweden)
Available from: 2010-11-19 Created: 2010-11-19 Last updated: 2018-01-12
Saldamli, L. & Fritzson, P. (2002). Extending Modelica for Partial Differential Equations. In: : . Paper presented at Proceedings of the 2nd International Modelica Conference. Oberpfaffenhofen, Germany: Modelica Assocation
Open this publication in new window or tab >>Extending Modelica for Partial Differential Equations
2002 (English)Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Oberpfaffenhofen, Germany: Modelica Assocation, 2002
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-62126 (URN)
Conference
Proceedings of the 2nd International Modelica Conference
Note

Oberpfaffenhofen, Germany, March 18-19, 2002

Available from: 2010-11-19 Created: 2010-11-19 Last updated: 2014-10-08
Aronsson, P., Fritzson, P., Saldamli, L. & Bunus, P. (2002). Incremental declaration handling in Open Source Modelica. In: : . Paper presented at Scandinavian Simulation Conference (SIMS), September 2002, Oulu, Finland..
Open this publication in new window or tab >>Incremental declaration handling in Open Source Modelica
2002 (English)Conference paper, Published paper (Refereed)
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-62133 (URN)
Conference
Scandinavian Simulation Conference (SIMS), September 2002, Oulu, Finland.
Available from: 2010-11-19 Created: 2010-11-19 Last updated: 2014-10-08
Saldamli, L. (2002). PDEModelica - Towards a High-Level Language for Modeling with Partial Differential Equations. (Licentiate dissertation). : Institutionen för datavetenskap
Open this publication in new window or tab >>PDEModelica - Towards a High-Level Language for Modeling with Partial Differential Equations
2002 (English)Licentiate thesis, monograph (Other academic)
Abstract [en]

This thesis describes initial language extensions to the Modelica language to define a more general language called PDEModelica, with built-in support for modeling with partial differential equations (PDEs). Modelica® is a standardized modeling language for objectoriented, equation-based modeling. It also supports component-based modeling where existing components with modified parameters can be combined into new models. The aim of the language presented in this thesis is to maintain the advantages of Modelica and also add partial differential equation support.

Partial differential equations can be defined using a coefficient-based approach, where a predefined PDE is modified by changing its coefficient values. Language operators to directly express PDEs in the language are also discussed. Furthermore, domain geometry description is handled and language extensions to describe geometries are presented. Boundary conditions, required for a complete PDE problem definition, are also handled.

A prototype implementation is described as well. The prototype includes a translator written in the relational meta-language, RML, and interfaces to external software such as mesh generators and PDE solvers, which are needed to solve PDE problems. Finally, a few examples modeled with PDEModelica and solved using the prototype are presented.

Place, publisher, year, edition, pages
Institutionen för datavetenskap, 2002. p. 92
Series
Linköping Studies in Science and Technology. Thesis, ISSN 0280-7971 ; 990
Keywords
Object oriented programming, mathematics models, partial differential equations (PDEs), relational meta-language (RML)
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-5732 (URN)91-7373-560-4 (ISBN)
Presentation
2002-12-18, 00:00 (English)
Note
Report code: LiU-Tek-Lic-2002:63.Available from: 2003-04-15 Created: 2003-04-15 Last updated: 2018-01-13
Fritzson, P., Aronsson, P., Bunus, P., Engelson, V., Saldamli, L., Johansson, H. & Karström, A. (2002). The Open Source Modelica Project. In: Martin Otter (Ed.), Proceedings from The 2nd International Modelica Conference was held March 18-19, 2002, Oberpfaffenhofen, Germany: . Paper presented at The 2nd International Modelica Conference was held March 18-19, 2002, Oberpfaffenhofen, Germany. (pp. 297-306). Modelica Association
Open this publication in new window or tab >>The Open Source Modelica Project
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2002 (English)In: Proceedings from The 2nd International Modelica Conference was held March 18-19, 2002, Oberpfaffenhofen, Germany / [ed] Martin Otter, Modelica Association , 2002, p. 297-306Conference paper, Published paper (Refereed)
Abstract [en]

The open source software movement has received enormous attention in recent years. It is often characterized as a fundamentally new way to develop software. This paper describes an effort to develop an open source Modelica environment  to  a  large  extent based on a formal specification of Modelica, coordinated by PELAB, Department of Computer and Information Science, Linköping University, Sweden. The current version of the system provides an efficient interactive computational environment for most of the expression, algorithm, and function parts of the Modelica language as well as an almost complete static semantics for Modelica 2.0.

The longer-term goal is to provide reasonable simulation execution support, at least for less complex models, also for the equation part of Modelica which is the real essence of the language. People are invited to contribute to this open source project, e.g. to provide implementations of numerical algorithms as Modelica functions, add-on tools to the environment, or contributions to compiler itself. The source code of the tool components of the open source Modelica environment is available under the Gnu Public License, GPL. The library components are available under the same conditions as the standard Modelica library. The system currently runs under Microsoft Windows, Linux, and Sun Sparc Solaris. A benchmark example of running a simplex algorithm shows that the performance of the current system is close to the performance of handwritten C code for the same algorithm.

Place, publisher, year, edition, pages
Modelica Association, 2002
Keywords
Modelica, Open Source
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-62119 (URN)
Conference
The 2nd International Modelica Conference was held March 18-19, 2002, Oberpfaffenhofen, Germany.
Available from: 2010-11-19 Created: 2010-11-19 Last updated: 2018-01-12Bibliographically approved
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