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  • 201.
    Pop, Adrian Dan Iosif
    et al.
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Towards Run-time Debugging of Equation-based Object-oriented Languages2007In: SIMS 2007 / [ed] Peter Bunus, Dag Fritzson and Claus Führer, Linköping: Linköping University Electronic Press , 2007, p. 134-139Conference paper (Other academic)
    Abstract [en]

    The development of today-s complex products requires advanced integrated environments and modeling languages for modeling and simulation. Equation-based object-oriented declarative (EOO) languages are emerging as the key approach to physical system modeling and simulation. The increased ease of use, the high abstraction and the expressivity of EOO languages are very attractive properties. However, these attractive properties come with the drawback that programming and modeling errors are often hard to find. In this paper we propose an integrated framework for run-time debugging of equation-based modeling languages. The framework integrates classical debugging techniques with special techniques for debugging EOO languages and is based on graph visualization and interaction. The debugging framework targets the Modelica language.

  • 202.
    Pop, Adrian Dan Iosif
    et al.
    Linköping University, Department of Computer and Information Science.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science.
    Jagudin, Elmir
    Linköping University, Department of Computer and Information Science.
    Remar, Andreas
    Linköping University, Department of Computer and Information Science.
    Akhvlediani, David
    Linköping University, Department of Computer and Information Science.
    OpenModelica Development Environment with Eclipse Integration for Browsing, Modeling, and Debugging2006Conference paper (Refereed)
    Abstract [en]

    The OpenModelica (MDT) Eclipse Plugin integrates the OpenModelica compiler and debugger with the Eclipse Integrated Development Environment Framework.. MDT, together with the OpenModelica compiler and debugger, provides an environment for Modelica development projects. This includes browsing, code completion through menus or popups, automatic indentation even of syntactically incorrect models, and model debugging. Simulation and plotting is also possible from a special command window. To our knowledge, this is the first Eclipse plugin for an equationbased language.

  • 203.
    Pop, Adrian Dan Iosif
    et al.
    Linköping University, Department of Computer and Information Science.
    Johansson, Olof
    Linköping University, Department of Computer and Information Science.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science.
    An integrated framework for model-driven design and development using Modelica2004In: Proceedings of SIMS 2004 the 45th International Conference of Scandinavian Simulation Society / [ed] Brian Elmegaard, Jon Sporring, Kenny Erleben, Kim Sørensen, 2004, p. 405-412Conference paper (Refereed)
    Abstract [en]

    This paper presents recent work in the area of model-driven product development processes. The focus is on the integration of product design tools with modeling and simulation tools. The goal is to provide automatic generation of models from product specifications using a highly integrated set of tools. Also, we provide the designer with the possibility of selecting the best design choice, verified through (automatic) simulation of different implementation alternatives of the same product model. To have a flexible interaction among various tools of the framework an XML representation of the Modelica modeling language called ModelicaXML is used. For efficient search in a large base of simulation models the Modelica Database was designed.

  • 204.
    Pop, Adrian Dan Iosif
    et al.
    Linköping University, Department of Computer and Information Science.
    Savga, Ilie
    Linköping University, Department of Computer and Information Science.
    Assmann, Uwe
    Linköping University, Department of Computer and Information Science.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science.
    Composition of XML Dialects: A ModelicaXML Case Study2005In: Electronical Notes in Theoretical Computer Science, ISSN 1571-0661, E-ISSN 1571-0661, Vol. 114, no SPEC. ISS., p. 137-152Article in journal (Refereed)
    Abstract [en]

    This paper investigates how software composition and transformation can be applied to domain specific languages used today in modeling and simulation of physical systems. More specifically, we address the composition and transformation of the Modelica language. The composition targets the ModelicaXML dialect which is the XML representation of the Modelica language. By extending the COMPOST concrete composition layer with a component model for Modelica, we provide composition and transformation of Modelica. The design of our COMPOST extension is presented togheter with examples of composition programs for Modelica.

  • 205.
    Pop, Adrian Dan Iosif
    et al.
    Linköping University, Department of Computer and Information Science.
    Savga, Ilie
    Linköping University, Department of Computer and Information Science.
    Assmann, Uwe
    Linköping University, Department of Computer and Information Science.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science.
    Composition of XML dialects: A ModelicaXML case study2004Conference paper (Refereed)
  • 206.
    Pop, Adrian Dan Iosif
    et al.
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Stavåker, Kristian
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Exception Handling for Modelica2008In: Proceedings of the 6th International Modelica Conference, March 3rd-4th, 2008. University of Applied Sciences Bielefeld, Bielefeld, Germany / [ed] Bernhard Bachmann, Modelica Website: Modelica Association , 2008, p. 409-417Conference paper (Refereed)
    Abstract [en]

    Any mature modeling and simulation language should provide support for error recovery. Errors might always appear in the runtime of such languages and the developer should be able to specify alternatives when failures happen. In this paper we present the design and implementation of exception handling in Modelica. To our knowledge this is the first approach of integrating equation-based object-oriented languages (EOO) with exception handling.

  • 207.
    Pop, Adrian
    et al.
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Debuging Natural Semantics Specifications2005In: Proceedings of the sixth international symposium on Automated analysis-driven debugging. AADEBUG'05, New York, NY, USA: ACM , 2005, p. 77-82Conference paper (Refereed)
    Abstract [en]

    In this paper we present the design and usage of a debugging framework for the Relational Meta-Language (RML), which is a language for writing executable Natural Semantics specifications. The language is successfully used at our department for writing large specifications for a range of languages like Java, Modelica, Pascal, MiniML etc. The RML system previously had no debugging facilities, which made it hard for programmers to debug their specifications. With this work we address these issues by providing a debugging framework for debugging high level Natural Semantics specifications in RML.

  • 208.
    Pop, Adrian
    et al.
    Linköping University, Department of Computer and Information Science.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science.
    The Modelica Standard Library as an Ontology for Modeling and Simulation of Physical Systems2004Report (Other academic)
    Abstract [en]

    This paper presents the Modelica Standard Library, an ontology used in modeling and simulation of physical systems. The Modelica Standard Library is continuously developed in the Modelica community. We present parts of the Modelica Standard Library and show an example of its usage. Also, in this paper we focus on the comparison of Modelica, the language used to specify the Modelica Standard Library with other ontology languages developed in the Semantic Web community.

  • 209.
    Pop, Adrian
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Sjölund, Martin
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Asghar, Adeel
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Casella, Francesco
    Politecnico di Milano, Italy.
    Integrated Debugging of Modelica Models2014In: Modeling, Identification and Control, ISSN 1890-1328, Vol. 35, no 2, p. 93-107Article in journal (Refereed)
    Abstract [en]

    The high abstraction level of equation-based object-oriented (EOO) languages such as Modelica has the drawback that programming and modeling errors are often hard to find. In this paper we present integrated static and dynamic debugging methods for Modelica models and a debugger prototype that addresses several of those problems. The goal is an integrated debugging framework that combines classical debugging techniques with special techniques for equation-based languages partly based on graph visualization and interaction. To our knowledge, this is the first Modelica debugger that supports both equation-based transformational and algorithmic code debugging in an integrated fashion.

  • 210.
    Qin, Xiaolin
    et al.
    Linköping University, Department of Computer and Information Science. Linköping University, Faculty of Science & Engineering. Chinese Academic Science, Peoples R China.
    Tang, Juan
    Chinese Academic Science, Peoples R China.
    Feng, Yong
    Chinese Academic Science, Peoples R China.
    Bachmann, Bernhard
    Bielefeld University of Appl Science, Germany.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Efficient index reduction algorithm for large scale systems of differential algebraic equations2016In: Applied Mathematics and Computation, ISSN 0096-3003, E-ISSN 1873-5649, Vol. 277, p. 10-22Article in journal (Refereed)
    Abstract [en]

    In many mathematical models of physical phenomenons and engineering fields, such as electrical circuits or mechanical multibody systems, which generate the differential algebraic equations (DAEs) systems naturally. In general, the feature of DAEs is a sparse large scale system of fully nonlinear and high index. To make use of its sparsity, this paper provides a simple and efficient algorithm for index reduction of large scale DAEs system. We exploit the shortest augmenting path algorithm for finding maximum value transversal (MVT) as well as block triangular forms (BTFs). We also present the extended signature matrix method with the block fixed point iteration and its complexity results. Furthermore, a range of nontrivial problems are demonstrated by our algorithm. (C) 2015 Elsevier Inc. All rights reserved.

  • 211.
    Reed, Todd
    et al.
    University of California, USA.
    Reed, Nancy
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Model based heart sound analysisfor the detection of diagnostically relevant symptoms2000Conference paper (Refereed)
  • 212.
    Reed, TR
    et al.
    Department of Electrical Engineering, University of Hawaii, USA.
    Reed, Nancy
    Department of Electrical Engineering, University of Hawaii, USA.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science.
    Heart sound analysis for symptom detection and computer-aided diagnosis2004In: Simulation Modelling Practice and Theory, ISSN 1569-190X, Vol. 12, no 2, p. 129-146Article in journal (Refereed)
    Abstract [en]

    Heart auscultation (the interpretation by a physician of heart sounds) is a fundamental component of cardiac diagnosis. It is, however, a difficult skill to acquire. In this work, we develop a simple model for the production of heart sounds, and demonstrate its utility in identifying features useful in diagnosis. We then present a prototype system intended to aid in heart sound analysis. Based on a wavelet decomposition of the sounds and a neural network-based classifier, heart sounds are associated with likely underlying pathologies. Preliminary results promise a system that is both accurate and robust, while remaining simple enough to be implemented at low cost.

  • 213.
    Ringström, Johan
    et al.
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Fagerström, Johan
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    PREDULA - A Multi-Paradigm Parallel Programming and Debugging Environment, 1991Conference paper (Refereed)
    Abstract [en]

    This paper describes the design, implementation and experience of the PREDULA parallel programming language and debugging environment. The motivation is to integrate parallel programming primitives from different paradigms for the purpose of teaching and simulating real-time systems. Semaphores, monitors, communication channels, and restricted ADA rendezvous and processes are all available. Together they simplify teaching of parallel programming and give rise to synergy effects when combined. The system has been successfully used in parallel programming courses at Linköping University.PREDULA primarily inherit from PASCAL and ADA. It is compiled into the ANTS interpreted stack based language, supporting a large number of lightweight processes.

  • 214.
    Ringström, Johan
    et al.
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Pettersson, Mikael
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Generating an efficient compiler for a data parallel language from a denotational specification1994In: Compiler Construction / [ed] Peter A. Fritzson, Springer Berlin/Heidelberg, 1994, p. 248-262Conference paper (Refereed)
    Abstract [en]

    There are very few examples of the generation of efficient compilers from denotational specifications. Usually such compilers generate code which is orders of magnitude slower than from hand-written ones. However, as has been demonstrated by our DML (Denotational Meta Language) compiler generation system, through appropriate single-threading analysis it is possible to obtain code of comparable quality to hand-written compilers. Another problem with denotational specifications is, because of their denotational nature, the need to introduce complicated power domains to model non-determinism and parallelism. In this work we have used a more practical two-level approach: use denotational specifications to model the meaning of the source language in terms of an abstract machine of low-level operations, including data-parallel operations. Then use operational semantics for the specification of this abstract machine.

    This paper reports experience from building a prototype compiler for a small Algol-like parallel language using a version of the DML system called DML-P, which has been extended to support data-parallel operations. The final code contains calls to a portable data-parallel vector code library (VCODE CVL). The speed of generated compilers are within a factor of three from handwritten ones. Extensive benchmarks of a DML-P generated compiler are presented.

  • 215.
    Ritzau, Tobias
    et al.
    Linköping University, Department of Computer and Information Science.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science.
    Decreasing Memory Overhead in Embedded Systems2002Conference paper (Refereed)
  • 216.
    Ritzau, Tobias
    et al.
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Decreasing memory overhead in hard real-time garbage collection2002In: Embedded Software: Second International Conference, EMSOFT 2002 Grenoble, France, October 7–9, 2002 Proceedings / [ed] Alberto Sangiovanni-Vincentelli and Joseph Sifakis, Springer Berlin/Heidelberg, 2002, Vol. 2491, p. 213-226Chapter in book (Refereed)
    Abstract [en]

    Automatic memory management techniques eliminate many programming errors that are both hard to find and to correct. However, these techniques are not yet used in embedded systems with hard real-time applications. The reason is that current methods for automatic memory management have a number of drawbacks: The two major ones are: (1) not being able to always guarantee short real-time deadlines and (2) using large amounts of extra memory. Memory is usually a scarce resource in embedded applications. In this paper we present a new technique, Real-Time Reference Counting (RTRC) that overcomes the current problems and makes automatic memory management attractive also for hard real-time applications. The main contribution of RTRC is that often all memory can be used to store live objects. This should be compared to a memory overhead of about 500% for garbage collectors based on copying techniques and about 50% for garbage collectors based on mark-and-sweep techniques.

  • 217.
    Ritzau, Tobias
    et al.
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Decreasing Memory Overhead in Hard Real-Time Garbage Collection2002In: Embedded Software / [ed] Sangiovanni-Vincentelli, Alberto, Sifakis, Joseph, Springer Berlin/Heidelberg, 2002, p. 213-226Conference paper (Refereed)
    Abstract [en]

    Automatic memory management techniques eliminate many programming errors that are both hard to find and to correct. However, these techniques are not yet used in embedded systems with hard realtime applications. The reason is that current methods for automatic memory management have a number of drawbacks. The two major ones are: (1) not being able to always guarantee short real-time deadlines and (2) using large amounts of extra memory. Memory is usually a scarce resource in embedded applications. In this paper we present a new technique, Real-Time Reference Counting (RTRC) that overcomes the current problems and makes automatic memory management attractive also for hard real-time applications. The main contribution of RTRC is that often all memory can be used to store live objects. This should be compared to a memory overhead of about 500% for garbage collectors based on copying techniques and about 50% for garbage collectors based on mark-and-sweep techniques.

  • 218.
    Rogovchenko, Olena
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Expressing Requirements in Modelica2014Conference paper (Refereed)
    Abstract [en]

    As cyber-physical systems grow increasingly complex, the need for methodologies and tool support for an automated requirement verification process becomes evident. Expressing requirements in a computable form becomes a crucial step in defining such a process. The equation based declarative nature of the Modelica language makes it an ideal candidate for modeling a large subset of system requirements. Moreover, modeling both the requirements and the system itself in the same language presents numerous advantages. However, a certain semantic gap subsists between the notions used in requirement modeling and the concepts of cyber-physical modeling that Modelica relies on. To bridge this gap, in this paper, we illustrate through the use of dedicated types, pseudo function calls and function block libraries, how the Modelica language can be tailored to fit the needs of requirement modeling engineers.

  • 219.
    Rogovchenko, Olena
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Tundis, Andrea
    University of Calabria, Italy .
    Zoheb Hossain, Muhammed
    Scania AB, Södertälje, Sweden.
    Nyberg, Mattias
    Scania AB, Södertälje, Sweden.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    An integrated toolchain for model based functional safety analysis2014In: Journal of Computational Science, ISSN 1877-7503, E-ISSN 1877-7511, Vol. 5, no 3, p. 408-414Article in journal (Refereed)
    Abstract [en]

    The significant increase in the complexity and autonomy of the hardware systems renders the verification of the functional safety of each individual component as well as of the entire system a complex task and underlines the need for integrated, model based tools that would assist this process. In this paper the authors present such a tool, coupled with an approach to functional safety analysis, based on the integration of functional tests into the model itself. The analysis of the resulting model is done through a stochastic Bayesian model. This approach strives to both bypass the necessity for costly hardware testing and integrate the functional safety analysis into an intuitive component development process.

  • 220.
    Saldamli, Levon
    et al.
    Linköping University, Department of Computer and Information Science.
    Bachmann, L
    Wiesmann, B
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science.
    A Framework for Describing and Solving PDE Models in Modelica2005Conference paper (Other academic)
  • 221.
    Saldamli, Levon
    et al.
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    A Modelica-Based Language for Object-Oriented Modeling with Partial Differential Equations2001Conference paper (Refereed)
  • 222.
    Saldamli, Levon
    et al.
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Domains and Partial Differential Equations in Modelica2001Conference paper (Refereed)
    Abstract [en]

    Modelica — is an equation-based object-oriented modeling language that supports models containing ordinary differential equations and differential and algebraic equations. In this article, we make an object-oriented design for extending Modelica with partial differential equations (PDEs) in order to describe and solve initial and boundary-value problems. We present constructs for geometric description of domains and domain boundaries using parametric expressions, and a hierarchical specification of PDEs and boundary conditions using inheritance, with a general PDE as a base model and more specific, application oriented sub-models. Using instances of PDE models, boundary conditions and domains we specify a complete PDE problem. Two environments used for prototype implementations are also described.

  • 223.
    Saldamli, Levon
    et al.
    Linköping University, Department of Computer and Information Science.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science.
    Extending Modelica for Partial Differential Equations2002Conference paper (Refereed)
  • 224.
    Saldamli, Levon
    et al.
    Linköping University, Department of Computer and Information Science.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science.
    Field Type and Field Constructor in Modelica2004Conference paper (Other academic)
  • 225.
    Samlaus, Roland
    et al.
    Fraunhofer Institute Wind Energy and Energy Syst Technology, Germany.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Semantic validation of physical models using role models2015In: Simulation (San Diego, Calif.), ISSN 0037-5497, E-ISSN 1741-3133, Vol. 91, no 4, p. 383-399Article in journal (Refereed)
    Abstract [en]

    The complexity of models for the simulation of physical systems is steadily increasing. This makes the effective validation of models for different design aspects crucial. One of the many important aspects is the structural correctness and the behavior due to design parameters which are of particular concern for the modeling of wind turbines. This article presents a design and implementation of a role-based validation framework. The framework allows for the creation of validation rules for different design aspects. This is done by role models that are used to define restrictions for an aspect by roles and rules. Multiple role models can be combined to cover all design features during model development. Restrictions on how models can interact with each other can be defined, which broadens language-specific restriction capabilities. The resulting rules can then be tested on arbitrary models based on the Eclipse Modeling Framework, for which mapping between elements of the role model and elements of the validated modeling language must be provided. In the domain of wind turbines, this approach is evaluated by application to two kinds of modeling languages (Modelica and UML2). Role models and rules have shown to be easily described with the frameworks role model language and role model definitions are successfully re-used by the definition of mappings for both kinds of modeling languages.

  • 226.
    Sandholm, Anders
    et al.
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology. University of Kalmar, Sweden.
    Bunus, Peter
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    A Numeric Library for Use in Modelica Simulations with Lapack, SuperLU, Interpolation, and MatrixIO2006Conference paper (Refereed)
    Abstract [en]

    This paper introduces a numerical Modelica library that provides access to some of the most well-known powerful libraries for numerical methods. Our approach has been to develop wrappers that allow Modelica users easy access as functions both from textual and graphical Modelica environments . This library also includes additional external functions withcorresponding Modelica wrappers to interpolate data and to read/write matrix data from/to files.

  • 227.
    Sandholm, Anders
    et al.
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology. Health Institute, Kalmar, Sweden .
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Arora, Varun
    Stanford University, USA.
    Delp, Scott
    Stanford University, USA.
    Petersson, Göran
    Health Institute, Kalmar, Sweden .
    Rose, Jessica
    Stanford University, USA.
    The Gait E-Book - Development of Effective Participatory Learning using Simulation and Active Electronic Books2007In: 11th Mediterranean Conference on Medical and Biomedical Engineering and Computing 2007, Springer Berlin/Heidelberg, 2007, p. 685-688Conference paper (Refereed)
    Abstract [en]

    In this paper we outline an interactive electronic book that teaches high school students about human locomotion. Today the most common teaching methods are lectures or reading a static textbook where the student’s participation is passive and they do not engage in the learning process. When learning about human gait, students not only learn anatomy and kinesiology but also have the opportunity to grasp theoretical subjects such as mathematics, physics, biomechanics as well as concepts of modeling and simulation to carry out experiments. In this paper we outline an interactive electronic book where the student becomes engaged in the learning processes, they can add/remove text, images, video, create models and perform simulation in one environment. The Gait E-book combines the theoretical lecture with the interactive learning process of modeling and simulation. Two different simulation platforms will be supported in the E-book, OpenModelica and OpenSim. Modelica is a powerful modern equation based simulation language where students can focus on learning mathematical and physical behavior.

  • 228.
    Sandholm, Anders
    et al.
    Linköping University, Department of Computer and Information Science.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science.
    Nilsson, Gunilla
    Petersson, Göran
    Towards a Flexible General Training Simulator Platform Based on Modelica2006Conference paper (Refereed)
  • 229.
    Schamai, Wladimir
    et al.
    Airbus Group Innovations, Germany.
    Buffoni, Lena
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Albarello, Nicolas
    Airbus Group Innovations, France.
    Fontes De Miranda, Pablo
    Airbus Group Innovations, France.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    An Aeronautic Case Study for Requirement Formalization and Automated Model Composition in Modelica2015In: Proceedings of the 11th International Modelica Conference, Versailles, France, September 21-23, 2015 / [ed] Peter Fritzson, Hilding Elmqvist, Linköping: Linköping University Electronic Press, 2015, p. 911-920, article id 99Conference paper (Refereed)
    Abstract [en]

    Building complex systems from models that have been developed separately without modifying existing code is a challenging task faced on a regular basis in multiple contexts including design verification. To address this issue an approach has been developed for automating dynamic system model composition by defining the minimum set of information that is necessary to the composition process. In this paper a design and implementation of this approach for standard Modelica is presented in the context of an application case study – the verification of a new design for spoiler activation against requirements.

  • 230.
    Schamai, Wladimir
    et al.
    Airbus Group Innovations, Hamburg, Germany.
    Buffoni, Lena
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    An Approach to Automated Model Composition Illustrated in the Context of Design Verification2014In: Modeling, Identification and Control, ISSN 1890-1328, Vol. 35, no 2, p. 79-91Article in journal (Refereed)
    Abstract [en]

    Building complex systems form models that were developed separately without modifying existing code is a challenging task faced on a regular basis in multiple contexts, for instance, in design verification. To address this issue, this paper presents a new approach for automating the dynamic system model composition. The presented approach aims to maximise information reuse, by defining the minimum set of information that is necessary to the composition process, to maximise decoupling by removing the need for explicit interfaces and to present a methodology with a modular and structured approach to composition. Moreover the presented approach is illustrated in the context of system design verification against requirements using a Modelica environment, and an approach for expressing the information necessary for automating the composition is formalized.

  • 231.
    Schamai, Wladimir
    et al.
    EADS Innovation Works, Hamburg, Germany.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Paredis, Chris J J
    Georgia Institute of Technology, Atlanta, GA, USA .
    Translation of UML state machines to Modelica: Handling semantic issues2013In: Simulation (San Diego, Calif.), ISSN 0037-5497, E-ISSN 1741-3133, Vol. 89, no 4, p. 498-512Article in journal (Refereed)
    Abstract [en]

    ModelicaML is a UML profile that enables modeling and simulation of systems and their dynamic behavior. ModelicaML combines the power of the OMG UML standardized graphical notation for systems and software modeling, and the simulation power of Modelica. This addresses the increasing need for precise and integrated modeling of products containing both software and hardware. This article discusses the usage of executable UML state machines for system modeling, i.e. usage of the same formalism for describing the state-based dynamic behavior of physical system components and software. Moreover, it points out that the usage of Modelica as an action language enables an integrated simulation of continuous-time and reactive/event-based system dynamics. The main purpose of this article is however to highlight issues that are identified regarding the UML specification which are experienced with typical executable implementations of UML state machines. The issues identified are resolved and rationales for the taken design decisions are provided.

  • 232.
    Schamai, Wladimir
    et al.
    EADS Innovation Works, Hamburg, Germany.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Paredis, Chris
    Georgia Institute of Technology, Atlanta, USA.
    Pop, Adrian
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Towards Unified Systems Modeling and Simulation with ModelicaML: Modeling of Executable Behavior Using Graphical Notations2009In: Proceedings of the 7th International Modelica Conference, Como, Italy, 20-22 September 2009, Linköping, Sweden: Linköping University Electronic Press, 2009, p. 612-621Conference paper (Refereed)
    Abstract [en]

    This paper is a further step towards application of the Model-Based Systems Engineering (MBSE) paradigm, using standardized, graphical, and executable system modeling languages. It presents further development of Modelica graphical Modeling Language (ModelicaML), a UML Profile for Modelica, which enables an integrated modeling and simulation of system requirements and design (for systems including both hardware and software). This approach combines the power of the OMG UML/SysML standardized graphical notation for system and software modeling, and the modeling and simulation power of Modelica. It facilitates the creation of executable system-specification and analysis models that can simulate time-discrete (or eventbased) and time-continuous system behavior.

  • 233.
    Schamai, Wladimir
    et al.
    EADS Innovation Works, Germany.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Paredis, Christian J.J
    Georgia Institute of Technology, Atlanta, USA.
    Helle, Philipp
    EADS Innovation Works, Germany.
    ModelicaML Value Bindings for Automated Model Composition2012Conference paper (Refereed)
    Abstract [en]

    Virtual Verification of Designs against Requirements (vVDR) is a method for model-based system design verification. This paper discusses enhancements to the vVDR method and its implementation in ModelicaML to further improve the support of system verification activities by automation. In the vVDR method there are different kinds of models that are created independently. However, they will become dependent and need to be related to each other in some concrete verification context. The aim is to reduce modeling errors and modeling efforts by automatically composing verification models from their constituting sub-models based on data dependencies that are defined using so-called mediators, which allow the expression of data dependencies between models without affecting, i.e. changing, the models themselves.

  • 234.
    Schamai, Wladimir
    et al.
    EADS Innovation Works, Germany.
    Helle, Philipp
    EADS Innovation Works, UK.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Virtual Verification of System Designs against System Requirements2010In: Models in Software Engineering, Springer Berlin/Heidelberg, 2010, p. 75-89Conference paper (Refereed)
    Abstract [en]

    System development and integration with a sufficient maturity at entry into service is a competitive challenge in the aerospace sector. With the ever-increasing complexity of products, this can only be achieved using efficient model-based techniques for system design as well as for system testing. However, natural language requirements engineering is an established technique that cannot be completely replaced for a number of reasons. This is a fact that has to be considered by any new approach. Building on the general idea of model-based systems engineering, we aim at building an integrated virtual verification environment for modeling systems, requirements, and test cases, so that system designs can be simulated and verified against the requirements in the early stages of system development. This paper provides a description of the virtual verification of system designs against system requirements methodology and exemplifies its application in a ModelicaML modeling environment.

  • 235.
    Schamai, Wladimir
    et al.
    Airbus.
    Pohlmann, U.
    Department of Computer Science, University of Paderborn, Germany.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science.
    Paredis, C.J.J.
    Georgia Institute of Technology, Atlanta, United States.
    Helle, P.
    EADS Innovation Works, Germany.
    Strobel, C.
    EADS Innovation Works, Germany.
    Execution of UML state machines using modelica2010In: Proceedings of the 3rd International Workshop on Equation-Based Object-Oriented Modeling Languages and Tools, EOOLT 2010 - In Conjunction with MODELS 2010, Linköping University Electronic Press , 2010, p. 1-10Conference paper (Refereed)
    Abstract [en]

    ModelicaML is a UML profile for the creation of executable models. ModelicaML supports the Model-Based Systems Engineering (MBSE) paradigm and combines the power of the OMG UML standardized graphical notation for systems and software modeling, and the simulation power of Modelica. This addresses the increasing need for precise integrated modeling of products containing both software and hardware. This paper focuses on the implementation of executable UML state machines in ModelicaML and demonstrates that using Modelica as an action language enables the integrated modeling and simulation of continuous-time and reactive or event-based system dynamics. More specifically, this paper highlights issues that are identified in the UML specification and that are experienced with typical executable implementations of UML state machines. The issues identified are resolved and rationales for design decisions taken are discussed.

  • 236.
    Shahmehri, Nahid
    et al.
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Algorithmic debugging for imperative languages with side-effects1990In: Compiler Compilers / [ed] Dieter Hammer, Springer Berlin/Heidelberg, 1990, p. 226-227Conference paper (Refereed)
    Abstract [en]

    Algorithmic debugging is a technique for semi-automatic localization of program errors. So far, this technique has been limited to programs without side-effects, and has only been applied to Prolog programs. In this paper, we generalize the algorithmic debugging method to programs written in imperative languages, e.g. Pascal, which may contain side-effects.

  • 237.
    Shahmehri, Nahid
    et al.
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Kamkar, Mariam
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Semi-automatic bug localization in software maintenance1990In: Software Maintenance, 1990, IEEE , 1990, p. 30-36Conference paper (Refereed)
    Abstract [en]

     An algorithmic program debugger for imperative languages is presented, with Pascal as an example case. This debugger extends the power of existing debuggers by providing an interactive debugging facility where errors can be localized semiautomatically. The debugger is activated on demand when the user discovers a symptom of an error as the result of some computation. This symptom presumably denotes a difference between the intended program behavior and the actual behavior. The proposed approach consists of three phases: program transformation, tracing, and debugging. The first phase transforms the source program into an internal representation which is appropriate, according to the Shapiro model, for algorithmic debugging. This phase produces an intermediate program which is free from side effects and loops. The program tracing phase generates trace information which builds an execution tree for the erroneous program. The debugging phase performs bug localization through a number of user interactions. This phase consists of pure algorithmic program debugging and program slicing

  • 238.
    Shahmehri, Nahid
    et al.
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Kamkar, Mariam
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Usability criteria for automated debugging systems1995In: Journal of Systems and Software, ISSN 0164-1212, E-ISSN 1873-1228, Vol. 31, no 1, p. 55-70Article in journal (Refereed)
    Abstract [en]

    Much of the current discussion around automated debugging systems is centered around various technical issues. In contrast, this paper focuses on user oriented usability criteria for automated debugging systems, and reviews several systems according to these criteria. We introduce four usability criteria: generality, cognitive plausibility, degree of automation and appreciation of the user's expertise. A debugging system which is general is able to understand a program without restrictive assumptions about the class of algorithms, the implementation, etc. A cognitively plausible debugging system supports debugging according to the user's mental model, e.g. by supporting several levels of abstraction and directions of bug localization. A high degree of automation means that fewer interactions with the user are required to find a bug. A debugging system that appreciates the user's expertise is suitable for both expert and novice programmers, and has the ability to take advantage of the additional knowledge of an expert programmer to speed up and improve the debugging process. Existing automated debugging systems fulfill these user-oriented requirements to a varying degree. However, many improvements are still needed to make automated debugging systems attractive to a broad range of users.

  • 239.
    Shahmehri, Nahid
    et al.
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Kamkar, Mariam
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Usability criteria for automated debugging systems1993In: Automated and Algorithmic Debugging / [ed] Peter A. Fritzson, Springer Berlin/Heidelberg, 1993, p. 16-39Conference paper (Refereed)
    Abstract [en]

    Much of the current discussion around automated debugging systems is centered around various technical issues. In contrast, this paper focuses on user oriented usability criteria for automated debugging systems, and reviews several systems according to these criteria. We introduce four usability criteria: generality, cognitive plausibility, degree of automation and appreciation of the user's expertise. A debugging system which is general is able to understand a program without restrictive assumptions about the class of algorithms, the implementation, etc. A cognitively plausible debugging system supports debugging according to the user's mental model, e.g. by supporting several levels of abstraction and directions of bug localization. A high degree of automation means that fewer interactions with the user are required to find a bug. A debugging system that appreciates the user's expertise is suitable for both expert and novice programmers, and has the ability to take advantage of the additional knowledge of an expert programmer to speed up and improve the debugging process. Existing automated debugging systems fulfill these user-oriented requirements to a varying degree. However, many improvements are still needed to make automated debugging systems attractive to a broad range of users.

  • 240.
    Sheshadri, Krishnamurthy
    et al.
    Connexios Life Sciences, Bangalore, India.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    A general symbolic PDE solver generator: Beyond explicit schemes2003In: Scientific Programming, ISSN 1058-9244, E-ISSN 1875-919X, Vol. 11, no 3, p. 225-235Article in journal (Refereed)
    Abstract [en]

    This paper presents an extension of our Mathematica- and MathCode-based symbolic-numeric framework for solving a variety of partial differential equation (PDE) problems. The main features of our earlier work, which implemented explicit finite-difference schemes, include the ability to handle (1) arbitrary number of dependent variables, (2) arbitrary dimensionality, and (3) arbitrary geometry, as well as (4) developing finite-difference schemes to any desired order of approximation. In the present paper, extensions of this framework to implicit schemes and the method of lines are discussed. While C++ code is generated, using the MathCode system for the implicit method, Modelica code is generated for the method of lines. The latter provides a preliminary PDE support for the Modelica language. Examples illustrating the various aspects of the solver generator are presented.

  • 241.
    Sheshadri, Krishnamurthy
    et al.
    Connexios Life Sciences, Bangalore, India.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    A General Symbolic PDE-Solver Generator: Explicit Schemes2003In: Scientific Programming, ISSN 1058-9244, E-ISSN 1875-919X, Vol. 11, no 1, p. 39-55Article in journal (Refereed)
    Abstract [en]

    A symbolic solver generator to deal with a system of partial differential equations (PDEs) in functions of an arbitrary number of variables is presented; it can also handle arbitrary domains (geometries) of the independent variables. Given a system of PDEs, the solver generates a set of explicit finite-difference methods to any specified order, and a Fourier stability criterion for each method. For a method that is stable, an iteration function is generated symbolically using the PDE and its initial and boundary conditions. This iteration function is dynamically generated for every PDE problem, and its evaluation provides a solution to the PDE problem. A C++/Fortran 90 code for the iteration function is generated using the MathCode system, which results in a performance gain of the order of a thousand over Mathematica, the language that has been used to code the solver generator. Examples of stability criteria are presented that agree with known criteria; examples that demonstrate the generality of the solver and the speed enhancement of the generated C++ and Fortran 90 codes are also presented.

  • 242.
    Sheshadri, Krishnamurthy
    et al.
    Connexios Life Sciences, Bangalore, India.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    MathPDE: A Package to Solve PDEs by Finite Differences2011In: The Mathematica journal, ISSN 1047-5974, E-ISSN 1097-1610, Vol. 13Article in journal (Refereed)
    Abstract [en]

    A package for solving time-dependent partial differential equations (PDEs), MathPDE, is presented. It implements finite-difference methods. After making a sequence of symbolic transformations on the PDE and its initial and boundary conditions, MathPDE automatically generates a problem-specific set of Mathematica functions to solve the numerical problem, which is essentially a system of algebraic equations. MathPDE then internally calls MathCode, a Mathematica-to-C++ code generator, to generate a C++ program for solving the algebraic problem, and compiles it into an executable that can be run via MathLink. When the algebraic system is nonlinear, the Newton-Raphson method is used and SuperLU, a library for sparse systems, is used for matrix operations. This article discusses the wide range of PDEs that can be handled by MathPDE, the accuracy of the finite-difference schemes used, and importantly, the ability to handle both regular and irregular spatial domains. Since a standalone C++ program is generated to compute the numerical solution, the package offers portability.

  • 243.
    Shitahun, Alachew
    et al.
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Ruge, Vitalij
    University of Applied Sciences, Bielefeld, Germany.
    Gebremedhin, Mahder
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Bachmann, Bernhard
    University of Applied Sciences, Bielefeld, Germany.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Andersson, Joel
    Diehl, Moritz
    Engineering Center (OPTEC), Leuven, Belgium.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Model-Based Dynamic Optimization with OpenModelica and CasADi2013In: IFAC-AAC 2013, 2013, p. 446-451Conference paper (Refereed)
    Abstract [en]

    This paper demonstrates model-based dynamic optimization through the coupling of two open source tools: OpenModelica, which is a Modelica-based modeling and simulation platform, and CasADi, a framework for numerical optimization. The coupling uses a standardized XML format for exchange of differential-algebraic equations (DAE) models. OpenModelica supports export of models written in Modelica and the optimization language extension using this XML format, while CasADi supports import of models represented in this format. This allows users to define optimal control problems (OCP) using Modelica and optimization language specification, and solve the underlying model formulation using a range of optimization methods, including direct collocation and direct multiple shooting. The proposed solution has been tested on several industrially relevant optimal control problems, including a diesel-electric power train.

  • 244.
    Siemers, Alexander
    et al.
    Linköping University, Department of Computer and Information Science.
    Fritzson, Dag
    Linköping University, Department of Computer and Information Science.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science.
    Meta-Modeling for Multi-Physics Co-Simulations applied for OpenModelica2006Conference paper (Refereed)
  • 245.
    Siemers, Alexander
    et al.
    Linköping University, Department of Computer and Information Science.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science.
    Fritzson, Dag
    Linköping University, Department of Computer and Information Science.
    Encapsulation in Object-Oriented Modelling for Mechanical Systems Simulation: Comparison of Modelica and BEAST2009In: Proceedings of MATHMOD 2009 / [ed] I. Troch and F. Breitenecker, 2009Conference paper (Refereed)
    Abstract [en]

    In systems engineering and object-oriented design, encapsulation is a key concept to handle complexity. Interfaces are defined for the external interaction of a component, whereas internal details are hidden. Complex systems such as cars or airplanes consist of many components, which, in turn, consist of many components – hierarchically, through many levels. Therefore composition is built into modelling languages such as Modelica. External interfaces must be defined for external interaction, whereas internal components cannot be accessed if they are not available through these interfaces.

    However, in 3D mechanical systems modelling and design, it is natural to be able to connect components whose surfaces are externally available. For example, the motor belonging to a car can be externally accessible in the 3D view, even though it can be regarded as an internal component of the car.

    In this paper we compare two modelling approaches, one is Modelica used for systems engineering as well as modelling of multi-body systems and the other one is BEAST which is a specialised multi-body systems tool with good support for contact modelling. The current Modelica approach requires strict interfaces with encapsulation of internal components, whereas BEAST allows connections to internal components which are visible in a 3D view, which is often natural from the 3D mechanical systems point of view. For 3D mechanical systems, Modelica might be too strict, whereas BEAST might be too forgiving. Two different solutions are presented and discussed (in the form of possible Modelica extensions) to combine the advantages of both approaches.

  • 246.
    Sjölund, Martin
    et al.
    Linköping University, Department of Computer and Information Science.
    Braun, Robert
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science.
    Krus, Petter
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems.
    Towards Efficient Distributed Simulation in Modelica using Transmission Line Modeling2010In: 3rd International Workshop on Equation-Based Object-Oriented Modeling Languages and Tools, 2010Conference paper (Refereed)
    Abstract [en]

    The current development towards multiple processor cores in personal computers is making distribution and parallelization of simulation software increasingly important. The possible speedups from parallelism are however often limited with the current centralized solver algorithms, which are commonly used in today’s simulation environments. An alternative method investigated in this work utilizes distributed solver algorithms using the transmission line modeling (TLM) method. Creation of models using TLM elements to separate model components makes them very suitable for computation in parallel because larger models can be partitioned into smaller independent submodels. The computation time can also be decreased by using small numerical solver step sizes only on those few submodels that need this for numerical stability. This is especially relevant for large and demanding models. In this paper we present work in how to combine TLM and solver inlining techniques in the Modelica equation-based language, giving the potential for efficient distributed simulation of model components over several processors.

  • 247.
    Sjölund, Martin
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Casella, Francesco
    Politecnico di Milano, Italy.
    Dan Iosif Pop, Adrian
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Asghar, Adeel
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Braun, Willi
    FH Bielefeld, University of Applied Sciences, Germany.
    Ochel, Lennart
    FH Bielefeld, University of Applied Sciences, Germany.
    Bachmann, Bernhard
    FH Bielefeld, University of Applied Sciences, Germany.
    Integrated Debugging of Equation-Based Models2014In: Proceedings of the 10th International Modelica Conference / [ed] Hubertus Tummescheit and Karl-Erik Årzén, Linköping University Electronic Press, 2014, p. 195-204Conference paper (Refereed)
    Abstract [en]

    The high abstraction level of equation-based object-oriented languages (EOO) such as Modelica has the drawback that programming and modeling errors are often hard to find. In this paper we present the first integrated debugger for equation-based languages like Modelica; which can combine static and dynamic methods for run-time debugging of equation-based Modelica models during simulations. This builds on and extends previous results from a transformational static equation debugger and a dynamic debugger for the algorithmic subset of Modelica.

  • 248.
    Sjölund, Martin
    et al.
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    An OpenModelica Java External Function Interface Supporting MetaProgramming2009In: Proceedings of the 7th International Modelica Conference; Como; Italy; 20-22 September 2009 / [ed] Francesco Casella, Linköping: Linköping University Electronic Press, 2009, p. 184-192Conference paper (Refereed)
    Abstract [en]

    A complete Java interface to OpenModelica has been created; supporting both standard Modelica and the metamodeling extensions in MetaModelica. It is bidirectional; and capable of passing both standard Modelica data types; as well as abstract syntax trees and list structures to and from Java and process them in either Java or the OpenModelica Compiler. It currently uses the existing CORBA interface as well as JNI for standard Modelica. It is also capable of automatically generating the Java classes corresponding to MetaModelica code. This interface opens up increased possibilities for tool integration between OpenModelica and Java-based tools; since for example models or model fragments can be extracted from OpenModelica; processed in a Java tool; and put back into the main model representation in OpenModelica.

  • 249.
    Sjölund, Martin
    et al.
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Debugging symbolic transformations in equation systems2011In: Proceedings of the 4th International Workshop on Equation-Based Object-Oriented Modeling Languages and Tools, EOOLT 2011, Linköping University Electronic Press , 2011, p. 67-74Conference paper (Refereed)
    Abstract [en]

    How do you debug application models in an equation-based object-oriented (EOO) programming language? Compilers for these tools tend to optimize the model so heavily that it is hard to tell the origin of an equation during runtime. This work proposes and implements a prototype of a method that is efficient, yet manages to keep track of all the transformations/operations that the compiler performs on the model. The method also considers the ability to collapse certain operations so that they appear to the user as a single expandable operation. Using such a method enables makers of compilers for EOO programming languages to create debugging tools that contain sufficiently detailed information while still being appealing to the user as they minimize duplicate information.

  • 250.
    Sjölund, Martin
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Pop, Adrian
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Bootstrapping a Compiler for an Equation-Based Object-Oriented Language2014In: Modeling, Identification and Control, ISSN 0332-7353, E-ISSN 1890-1328, Vol. 35, no 1, p. 1-19Article in journal (Refereed)
    Abstract [en]

    What does it mean to bootstrap a compiler, and why do it? This paper reports on the first bootstrapping of a full-scale EOO (Equation-based Object-Oriented) modeling language such as Modelica. Bootstrapping means that the compiler of a language can compile itself. However, the usual application area for the Modelica is modeling and simulation of complex physical systems. Fortunately it turns out that with some minor extensions, the Modelica language is well suited for the modeling of language semantics. We use the name MetaModelica for this slightly extended Modelica. This is a prerequisite for bootstrapping which requires that the language can be used to model and/or implement itself. The OpenModelica Compiler (OMC) has been written in this MetaModelica language. It originally supported only the standard Modelica language but has been gradually extended to also cover the MetaModelica language extensions. After substantial work, OMC is able to quickly compile itself and produces an executable with good performance. The benefits include a more extensible and maintainable compiler by introducing improved language constructs and a more powerful runtime that makes it easy to add functionality such as parser generators, debuggers, and profiling tools. Future work includes extracting and restructuring parts of OMC, making the compiler smaller and more modular and extensible. This will also make it easier to interface with OMC, making it possible to create more powerful and user-friendly OpenModelica-based tools. The compiler and its bootstrapping is a major effort -- it is currently about 330 000 lines of code, and the MetaModelica extensions are used routinely by approximately ten developers on a daily basis. 

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