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  • 1.
    Aronsson, Peter
    et al.
    MathCore Engineering AB, Linköping, Sweden.
    Broman, David
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Extendable Physical Unit Checking with Understandable Error Reporting2009In: Proceedings of the 7th International Modelica Conference, Como, Italy, 20-22 September 2009, Linköping University Electronic Press, Linköpings universitet , 2009, 890-897 p.Conference paper (Refereed)
    Abstract [en]

    Dimensional analysis and physical unit checking are important tools for helping users to detect and correct mistakes in dynamic mathematical models. To make tools useful in a broad range of domains, it is important to also support other units than the SI standard. For instance, such units are common in biochemical or financial modeling. Furthermore, if two or more units turn out be in conflict after checking, it is vital that the reported unit information is given in an understandable format for the user, e.g., “N.m” should preferably be shown instead of “m2.kg.s-2”, even if they represent the same unit. Presently, there is no standardized solution to handle these problems for Modelica models. The contribution presented in this paper is twofold. Firstly, we propose an extension to the Modelica language that makes it possible for a library designer to define both new base units and derived units within Modelica models and packets. Today this information is implicitly defined in the specification. Secondly, we describe and analyze a solution to the problem of presenting units to users in a more convenient way, based on an algorithm using Mixed Integer Programming (MIP). Both solutions are implemented, tested, and illustrated with several examples.

  • 2.
    Broman, David
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Flow Lambda Calculus for Declarative Physical Connection Semantics2007Report (Other academic)
    Abstract [en]

    One of the most fundamental language constructs of equation-based object-oriented languages is the possibility to state acausal connections, where both potential variables and flow variables exist. Several of the state-of-the art languages in this category are informally specified using natural language. This can make the languages hard to interpret, reason about, and disable the possibility to guarantee the absence of certain errors. In this work, we construct a formal operational small-step semantics based on the lambda-calculus. The calculus is then extended with more convenient modeling capabilities. Examples are given that demonstrate the expressiveness of the language, and some tests are made to verify the correctness of the semantics.

  • 3.
    Broman, David
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Growing an Equation-Based Object-Oriented Modeling Language2009In: MATHMOD, 2009, 2009, 1316-1324 p.Conference paper (Other academic)
    Abstract [en]

    Equation-based object-oriented (EOO) modeling languages are typically rather complex. Such languages can unfortunately not be designed correctly once and for all, not least because all requirements and use cases are not known initially, and may never be known completely. Hence, there is a need to plan for modeling languages to grow in a sound manner. This paper discusses and analyzes how EOO languages in general can be designed for growth, and in particular how this relates to the evolution of the Modelica language. Different ways of growth are categorized and various stakeholders’ perspectives are discussed regarding what is important when growing a language.

  • 4.
    Broman, David
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Meta-Languages and Semantics for Equation-Based Modeling and Simulation2010Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Performing computational experiments on mathematical models instead of building and testing physical prototypes can drastically reduce the develop cost for complex systems such as automobiles, aircraft, and powerplants. In the past three decades, a new category of equation-based modeling languages has appeared that is based on acausal and object-oriented modeling principles, enabling good reuse of models.  However, the modeling languages within this category have grown to be large and complex, where the specifications of the language's semantics are informally defined, typically described in natural languages. The lack of a formal semantics makes these languages hard to interpret unambiguously and to reason about. This thesis concerns the problem of designing the semantics of such equation-based modeling languages in a way that allows formal reasoning and increased correctness. The work is presented in two parts.

    In the first part we study the state-of-the-art modeling language Modelica.  We analyze the concepts of types in Modelica and conclude that there are two kinds of type concepts: class types and object types. Moreover, a concept called structural constraint delta is proposed, which is used for isolating the faults of an over- or under-determined model.

    In the second part, we introduce a new research language called the Modeling Kernel Language (MKL). By introducing the concept of higher-order acausal models (HOAMs), we show that it is possible to create expressive modeling libraries in a manner analogous to Modelica, but using a small and simple language concept. In contrast to the current state-of-the-art modeling languages, the semantics of how to use the models, including meta operations on models, are also specified in MKL libraries. This enables extensible formal executable specifications where important language features are expressed through libraries rather than by adding completely new language constructs. MKL is a statically typed language based on a typed lambda calculus. We define the core of the language formally using operational semantics and prove type safety.  An MKL interpreter is implemented and verified in comparison with a Modelica environment.

  • 5.
    Broman, David
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Safety, Security, and Semantic Aspects of Equation-Based Object-Oriented Languages and Environments2007Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    During the last two decades, the interest for computer aided modeling and simulation of complex physical systems has witnessed a significant growth. The recent possibility to create acausal models, using components from different domains (e.g., electrical, mechanical, and hydraulic) enables new opportunities. Modelica is one of the most prominent equation-based object-oriented (EOO) languages that support such capabilities, including the ability to simulate both continuous- and discrete-time models, as well as mixed hybrid models. However, there are still many remaining challenges when it comes to language safety and simulation security. The problem area concerns detecting modeling errors at an early stage, so that faults can be isolated and resolved. Furthermore, to give guarantees for the absence of faults in models, the need for precise language specifications is vital, both regarding type systems and dynamic semantics.

    This thesis includes five papers related to these topics. The first paper describes the informal concept of types in the Modelica language, and proposes a new concrete syntax for more precise type definitions. The second paper provides a new approach for detecting over- and under-constrained systems of equations in EOO languages, based on a concept called structural constraint delta. That approach makes use of type checking and a type inference algorithm. The third paper outlines a strategy for using abstract syntax as a middle-way between a formal and informal language specification. The fourth paper suggests and evaluates an approach for secure distributed co-simulation over wide area networks. The final paper outlines a new formal operational semantics for describing physical connections, which is based on the untyped lambda calculus. A kernel language is defined, in which real physical models are constructed and simulated.

    List of papers
    1. Types in the Modelica Language
    Open this publication in new window or tab >>Types in the Modelica Language
    2006 (English)Conference paper, Published paper (Other academic)
    Abstract [en]

     

    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 com-

    pilers 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 Model-

    ica 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 defin-

    ition.

     

    Keyword
    type system; types; Modelica; simulation; modeling; type safety
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-12698 (URN)
    Conference
    Proceedings of the Fifth International Modelica Conference, Vienna 2006
    Available from: 2007-11-16 Created: 2007-11-16 Last updated: 2014-10-08
    2. Determining Over- and Under-Constrained Systems of Equations using Structural Constraint Delta
    Open this publication in new window or tab >>Determining Over- and Under-Constrained Systems of Equations using Structural Constraint Delta
    2006 (English)Conference paper, Published paper (Other academic)
    Abstract [en]

    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.

    Keyword
    equation-based, modeling, object-oriented, over-constrained, separate compilation, type checking, under-constrained, simulation languages, algorithms
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-12699 (URN)10.1145/1173706.1173729 (DOI)
    Conference
    Proceedings of the 5th International Conference on Generative Programming and Component Engineering
    Available from: 2007-11-16 Created: 2007-11-16 Last updated: 2014-10-08
    3. Abstract Syntax Can Make the Definition of Modelica Less Abstract
    Open this publication in new window or tab >>Abstract Syntax Can Make the Definition of Modelica Less Abstract
    2007 (English)In: Proceedings of the 1st International Workshop on Equation-Based Object-Oriented Languages and Tools, Berlin, Germany, 2007, 111-126 p.Conference paper, Published paper (Refereed)
    Abstract [en]

    Modelica is an open standardized language used for modeling and simulation of complex physical systems. The language specification defines a formal concrete syntax, but the semantics is informally described using natural language. The latter makes the language hard to interpret, maintain and reason about, which affect both tool development and language evolution. Even if a completely formal semantics of the Modelica language can be seen as a natural goal, it is a well-known fact that defining understandable and concise formal semantics specifications for large and complex languages is a very hard problem. In this paper, we will discuss different aspects of formulating a Modelica specification; both in terms of what should be specified and how it can be done. Moreover, we will further argue that a “middle-way” strategy can make the specification both clearer and easier to reason about. A proposal is outlined, where the current informally specified semantics is complemented with several grammars, specifying intermediate representations of abstract syntax. We believe that this kind of evolutionary strategy is easier to gain acceptance for, and is more realistic in the short-term, than a revolutionary approach of using a fully formal semantics definition of the language.

    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:liu:diva-12700 (URN)978-91-7519-822-4 (ISBN)
    Conference
    1st International Workshop on Equation-Based Object-Oriented Languages and Tools
    Available from: 2007-11-16 Created: 2007-11-16 Last updated: 2018-01-13
    4. Secure Distributed Co-Simulation over Wide Area Networks
    Open this publication in new window or tab >>Secure Distributed Co-Simulation over Wide Area Networks
    Show others...
    2007 (English)Conference paper, Published paper (Other academic)
    Abstract [en]

    Modeling and simulation often require different tools for specialized purposes, which increase the motivation to use co-simulation. Since physical models often are describing enterprises¿ primary know-how, there is a need for a sound approach to securely perform modeling and simulation. This paper discusses different possibilities from a security perspective, with focus on secure distributed co-simulation over wide area networks (WANs), using transmission line modeling (TLM). An approach is outlined and performance is evaluated both in a simulated WAN environment, and for a real encrypted co-simulation between Sweden and Australia. It is concluded that several parameters affect the total simulation time, where especially the network delay (latency) has a significant impact.

    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:liu:diva-12701 (URN)
    Conference
    Proceedings of the 48th Conference on Simulation and Modelling (SIMS'07), Gothenburg, Sweden
    Available from: 2007-11-16 Created: 2007-11-16 Last updated: 2018-01-13
    5. Flow Lambda Calculus for Declarative Physical Connection Semantics
    Open this publication in new window or tab >>Flow Lambda Calculus for Declarative Physical Connection Semantics
    2007 (English)Report (Other academic)
    Abstract [en]

    One of the most fundamental language constructs of equation-based object-oriented languages is the possibility to state acausal connections, where both potential variables and flow variables exist. Several of the state-of-the art languages in this category are informally specified using natural language. This can make the languages hard to interpret, reason about, and disable the possibility to guarantee the absence of certain errors. In this work, we construct a formal operational small-step semantics based on the lambda-calculus. The calculus is then extended with more convenient modeling capabilities. Examples are given that demonstrate the expressiveness of the language, and some tests are made to verify the correctness of the semantics.

    Place, publisher, year, edition, pages
    Linköping: Linköping University Electronic Press, 2007. 18 p.
    Series
    Technical reports in Computer and Information Science, ISSN 1654-7233 ; 1
    Keyword
    Flow connection, Flow Lambda Calculus, Operational Semantics
    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:liu:diva-12702 (URN)
    Available from: 2007-11-16 Created: 2007-11-16 Last updated: 2018-01-13Bibliographically approved
  • 6.
    Broman, David
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Should Software Engineering Projects be the Backbone or the Tail of Computing Curricula?2010In: Software Engineering Education and Training (CSEE&T), 2010, IEEE , 2010, 153-156 p.Conference paper (Refereed)
    Abstract [en]

    Most computer science (CS) and software engineering (SE) curricula include some form of SE project with the aim of lowering the gap between CS and SE education and real-world demands in industry. In this paper we briefly discuss and explain our findings of software engineering projects taught at LiU in Sweden. These courses use what we call the ¿tail¿ approach, where student projects are performed at the end of a degree program. We then argue that there are several problems with this approach and sketch an idea where SE projects are an integrated part of a curriculum. Furthermore, pros and cons of this idea, which we call the SE project ¿backbone¿ approach, are discussed and analyzed.

  • 7.
    Broman, David
    et al.
    Linköping University, Department of Computer and Information Science.
    Aronsson, Peter
    MathCore Engineering.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science.
    Design Considerations for Dimensional Inference and Unit Consistency Checking in Modelica2008Conference paper (Refereed)
    Abstract [en]

    The Modelica language supports syntax for declaring physical units of variables, but it does not yet exist any defined semantics for how dimensional and unit consistency checking should be carried out. In this paper we explore different approaches and new constructs for improved dimensional inference and unit consistency checking in Modelica; both from an end-user, library, and tool perspective. A proposal for how dimensional inference and unit checking can be carried out is outlined and a prototype implementation is developed and verified using several examples from the Modelica standard library.

  • 8.
    Broman, David
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology. University of Calif Berkeley, CA 94720 USA .
    Derler, Patricia
    University of Calif Berkeley, CA 94720 USA .
    Eidson, John C
    University of Calif Berkeley, CA 94720 USA .
    Temporal Issues in Cyber-Physical Systems2013In: JOURNAL OF THE INDIAN INSTITUTE OF SCIENCE, ISSN 0970-4140, Vol. 93, no 3, 389-402 p.Article, review/survey (Refereed)
    Abstract [en]

    This paper reviews the use of time, clocks, and clock synchronization protocols in cyber-physical systems (CPS). Recent advances in the area of timing suggest avenues of research and potential new application areas. We discuss how introducing timestamps and clocks can help overcome issues such as latency, jitter, and determining correct execution order. Furthermore, we show how system complexity can be reduced and distribution as well as parallelism can be done deterministically. We also point to recent work in raising time to first class citizen status in modeling and implementation. In particular, we describe design and execution environments of CPS and specialized hardware such as predictable timing architectures where time plays a key role.

  • 9.
    Broman, David
    et al.
    Linköping University, Department of Computer and Information Science.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science.
    Abstract Syntax Can Make the Definition of Modelica Less Abstract2007In: Proceedings of the 1st International Workshop on Equation-Based Object-Oriented Languages and Tools, Berlin, Germany, 2007, 111-126 p.Conference paper (Refereed)
    Abstract [en]

    Modelica is an open standardized language used for modeling and simulation of complex physical systems. The language specification defines a formal concrete syntax, but the semantics is informally described using natural language. The latter makes the language hard to interpret, maintain and reason about, which affect both tool development and language evolution. Even if a completely formal semantics of the Modelica language can be seen as a natural goal, it is a well-known fact that defining understandable and concise formal semantics specifications for large and complex languages is a very hard problem. In this paper, we will discuss different aspects of formulating a Modelica specification; both in terms of what should be specified and how it can be done. Moreover, we will further argue that a “middle-way” strategy can make the specification both clearer and easier to reason about. A proposal is outlined, where the current informally specified semantics is complemented with several grammars, specifying intermediate representations of abstract syntax. We believe that this kind of evolutionary strategy is easier to gain acceptance for, and is more realistic in the short-term, than a revolutionary approach of using a fully formal semantics definition of the language.

  • 10.
    Broman, David
    et al.
    Linköping University, Department of Computer and Information Science.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science.
    Higher-Order Acausal Models2008In: EOOLT 2008 / [ed] Peter Fritzson, François Cellier, David Broman, Linköping University Electronic Press , 2008, 59-69 p.Conference paper (Other academic)
    Abstract [en]

    Current equation-based object-oriented (EOO) languages typically contain a number of fairly complex language constructs for enabling reuse of models. However, support for model transformation is still often limited to scripting solutions provided by tool implementations. In this paper we investigate the possibility of combining the well known concept of higher-order functions, used in standard functional programming languages, with acausal models. This concept, called Higher-Order Acausal Models (HOAMs), simplifies the creation of reusable model libraries and model transformations within the modeling language itself. These transformations include general model composition and recursion operations and do not require data representation/reification of models as in metaprogramming/metamodeling. Examples within the electrical and mechanical domain are given using a small research language. However, the language concept is not limited to a particular language, and could in the future be incorporated into existing commercially available EOO-languages.

  • 11.
    Broman, David
    et al.
    Linköping University, Department of Computer and Information Science.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science.
    High-Order Acausal Models2009In: Simulation news europe, ISSN 0929-2268, Vol. 19, no 1Article in journal (Refereed)
  • 12.
    Broman, David
    et al.
    Linköping University, Department of Computer and Information Science.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science.
    Ideas for Security Assurance in Security Critical Software using Modelica2005Conference paper (Refereed)
    Abstract [en]

    Due to the increasing number of vulnerabilities in software systems and customers- need to trust the producers- development process, third party security evaluations, such as Common Criteria (CC), are today commonly used to provide assurance of security critical software. Modelica is a modern, strongly typed, declarative, and object-oriented language for modeling and simulation of complex systems. In this paper we sketch two ideas for improving security assurance, by expanding the scope of Modelica into also becoming a declarative modeling language for other application areas than simulation.

  • 13.
    Broman, David
    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.
    Type Safety of Equation-Based Object-Oriented Modeling Languages2006Conference paper (Refereed)
  • 14.
    Broman, David
    et al.
    Linköping University, Department of Computer and Information Science.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science.
    Type Safety of Equation-Based Object-Oriented Modeling Languages2006Other (Other (popular science, discussion, etc.))
  • 15.
    Broman, David
    et al.
    Linköping University, Department of Computer and Information Science.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science.
    Furic, Sébastien
    Imagine, France.
    Types in the Modelica Language2006Conference paper (Other academic)
    Abstract [en]

     

    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 com-

    pilers 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 Model-

    ica 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 defin-

    ition.

     

  • 16.
    Broman, David
    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, Software and Systems. Linköping University, The Institute of Technology.
    Hedin, Görel
    Lund University, Sweden.
    Åkesson, Johan
    Lund University, Sweden.
    A comparison of two metacompilation approaches to implementing a complex domain-specific language2012In: Proceedings of the 27th Annual ACM Symposium on Applied Computing, Association for Computing Machinery (ACM), 2012, 1919-1921 p.Conference paper (Refereed)
    Abstract [en]

    Operational semantics and attribute grammars are examples of formalisms that can be used for generating compilers. We are interested in finding similarities and differences in how these approaches are applied to complex languages, and for generating compilers of such maturity that they have users in industry.

    As a specific case, we present a comparative analysis of two compilers for Modelica, a language for physical modeling, and which contains numerous compilation challenges. The two compilers are OpenModelica, which is based on big-step operational semantics, and JModelica.org, which is based on reference attribute grammars.

  • 17.
    Broman, David
    et al.
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory.
    Nilsson, Henrik
    University of Nottingham.
    Node-Based Connection Semanticsfor Equation-Based Object-Oriented Modeling Languages2012In: Proceedings of Fourteenth International Symposium on Practical Aspects of Declarative Languages (PADL 2012), 2012, 258-272 p.Conference paper (Refereed)
  • 18.
    Broman, David
    et al.
    Linköping University, Department of Computer and Information Science.
    Nyström, Kaj
    Linköping University, Department of Computer and Information Science.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science.
    Determining Over- and Under-Constrained Systems of Equations using Structural Constraint Delta2006Conference paper (Other academic)
    Abstract [en]

    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.

  • 19.
    Broman, David
    et al.
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Sandahl, Kristian
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    How can we make software engineering text books well-founded, up-to-date, and accessible to students?2011In: Software Engineering Education and Training (CSEE&T), 2011, IEEE , 2011, 386-390 p.Conference paper (Refereed)
    Abstract [en]

    When teaching software engineering courses it is highly important to have good text books that are well-founded, up-to-date, and easily accessible to students. However, currently available text books on the market are either very broad or highly specialized, making it hard to select appropriate books for specific software engineering courses. Moreover, due to the rapidly changing subject of software engineering, books tend to become obsolete, which make students hesitate to buy books even if they are part of the listed course literature. In this paper, we briefly explain and discuss an approach of using a web-based system for creating collaborative and peer-reviewed text books that can be customized individually for specific courses. We describe and discuss the proposed system from a use case perspective.

  • 20.
    Broman, David
    et al.
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Sandahl, Kristian
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Abu Baker, Mohamed
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    The Company Approach to Software Engineering Project Courses2012In: IEEE Transactions on Education, ISSN 0018-9359, E-ISSN 1557-9638, Vol. 55, no 4, 445-452 p.Article in journal (Refereed)
    Abstract [en]

    Teaching larger software engineering project courses at the end of a computing curriculum is a way for students to learn some aspects of real-world jobs in industry. Such courses, often referred to as capstone courses, are effective for learning how to apply the skills they have acquired in, for example, design, test, and configuration management. However, these courses are typically performed in small teams, giving only a limited realistic perspective of problems faced when working in real companies. This paper describes an alternative approach to classic capstone projects, with the aim of being more realistic from an organizational, process, and communication perspective. This methodology, called the company approach, is described by intended learning outcomes, teaching/learning activities, and assessment tasks. The approach is implemented and evaluated in a larger Masters student course.

  • 21.
    Cellier, François
    et al.
    ETH Zürich.
    Broman, DavidLinköping University, Department of Computer and Information Science.Fritzson, PeterLinköping University, Department of Computer and Information Science.Lee, EdwardUniversity of California, Berkeley.
    Proceedings of the 4th International Workshop on Equation-Based Object-Oriented Modeling Languages and Tools2011Conference proceedings (editor) (Other academic)
  • 22.
    Fritzson, Peter
    et al.
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Aronsson, Peter
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Lundvall, Håkan
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Nyström, Kaj
    Linköping University, Department of Computer and Information Science.
    Pop, Adrian
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Saldamli, Levon
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Broman, David
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    The OpenModelica Modeling, Simulation, and Development Environment2005Conference 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.

  • 23.
    Fritzson, Peter
    et al.
    Linköping University, Department of Computer and Information Science.
    Broman, David
    Linköping University, Department of Computer and Information Science.
    Cellier, Francois
    Nytsch Geusen, Christoph
    Book Chapter: Workshop Reader of the Workshop EOOLT'2007 at ECOOP'2007, Object Oriented Technology2008In: Object-Oriented Technology. ECOOP 2007 Workshop Reader., Springer Verlag , 2008, 27-39 p.Chapter in book (Other academic)
  • 24.
    Fritzson, Peter
    et al.
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Broman, David
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Cellier, François
    ETH Zurich, Switzerland.
    Equation-based object-oriented languages and tools: Report on the 2nd workshop EOOLT at ECOOP 20082009In: Object-Oriented Technology. ECOOP 2008 Workshop Reader: ECOOP 2008 Workshops Paphos, Cyprus, July 7-11, 2008 Final Reports / [ed] Patrick Eugster, Springer Berlin/Heidelberg, 2009, 1, Vol. 5475 LNCS, 18-29 p.Chapter in book (Other academic)
    Abstract [en]

    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.

  • 25.
    Fritzson, Peter
    et al.
    Linköping University, Department of Computer and Information Science.
    Cellier, FrançoisETH Zürich.Broman, DavidLinköping University, Department of Computer and Information Science.
    Proceedings of the 2nd International Workshop on Equation-Based Object-Oriented Languages and Tools2008Conference proceedings (editor) (Other academic)
  • 26.
    Fritzson, Peter
    et al.
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Lee, Edward
    University of California, Berkeley, USA.
    Cellier, Francois
    ETH Zurich, Switzerland.
    Broman, David
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Equation-Based Object-Oriented Modeling Languages and Tools: Report on the Workshop EOOLT 2010 at MODELS 2010 Oslo, Norway, October 3, 20102011In: MODELS 2010 Workshops, Springer Berlin/Heidelberg, 2011, , 5 p.140-144 p.Chapter in book (Other academic)
    Abstract [en]

    EOOLT 2010 was the third edition of the EOOLT workshop series. The workshop is intended to bring together researchers and practitioners fromdifferent equation-based object-oriented (EOO) modeling language communities. This year’s workshop also expands the scope to include the whole design space of languages for cyber-physical systems, where physical dynamics are mixed with networks and software. The workshop gathered 31 participants to present and discuss thirteen different papers grouped into the four areas of real-time oriented modeling languages and tools, modeling language design, simulation and model compilation, and modeling and simulation tools.

  • 27.
    Fritzson, Peter
    et al.
    Linköping University, Department of Computer and Information Science.
    Lee, EdwardUniversity of California, Berkeley.Cellier, FrançoisETH Zürich.Broman, DavidLinköping University, Department of Computer and Information Science.
    Proceedings of the 3rd International Workshop on Equation-Based Object-Oriented Modeling Languages and Tools2010Conference proceedings (editor) (Other academic)
  • 28.
    Fritzson, Peter
    et al.
    Linköping University, Department of Computer and Information Science.
    Pop, Adrian
    Linköping University, Department of Computer and Information Science.
    Broman, David
    Linköping University, Department of Computer and Information Science.
    Aronsson, Peter
    Linköping University, Department of Computer and Information Science.
    Formal Semantics Based Translator Generation and Tool Development in Practice2009In: Proceedings of  20th Australian Software Engineering Conference (ASWEC 2009), Gold Coast, Queensland, Australia, April 14 – 17, 2009, IEEE Computer Society , 2009, 256-266 p.Conference paper (Refereed)
    Abstract [en]

    In this paper we report on a long-term research effort to develop and use efficient language implementation generators in practice. The generator is applied to a number of different languages, some of which are used for projects in industry. The used formal specification style is operational semantics, primarily in the form called natural semantics, represented and supported by a meta-language and tool called the relational meta language (RML), which can generate efficient implementations in C, on par with hand-implemented code. Generating implementations from formal specifications are assumed to give advantages such as: high level descriptions, higher degree of correctness, and consistency between specification and implementation. To what extent can this be realized in practice? Does it scale to large language implementations? To answer some of these questions we have developed specifications of a range of languages: imperative, functional, object-oriented (Java), and equation-based (Modelica). The size of specifications range from half a page to large specifications of 60 000 lines. It turns out to be possible to generate efficient compilers, also for large languages. However, the performance of the generator tool and the user support of the development environment become increasingly important for large specifications. To satisfy such user needs the speed of the generator was increased a factor of ten to reduce turn-around time, and an Eclipse plug-in including a debugger were developed. For very large specifications, the structuring and modularity of the specification itself also become essential for performance and maintainability.

  • 29.
    Fritzson, Peter
    et al.
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Pop, Adrian Dan Iosif
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Lundvall, Håkan
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Aronsson, Peter
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Nyström, Kaj
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Saldamli, Levon
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Broman, David
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Sandholm, Anders
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    OpenModelica - A Free Open-Source Environment for System Modeling, Simulation, and Teaching2006In: 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, 1588-1595 p.Conference 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.   

  • 30.
    Isaac, Liu
    et al.
    University of California, Berkeley, USA.
    Reineke, Jan
    Saarland University, Saarbrücken, Germany.
    Broman, David
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Zimmer, Michael
    University of California, Berkeley, USA.
    Lee, Edward
    University of California, Berkeley, USA.
    A PRET microarchitecture implementation with repeatable timing and competitive performance2012In: Computer Design (ICCD), 2012, IEEE , 2012, 87-93 p.Conference paper (Refereed)
    Abstract [en]

    We contend that repeatability of execution times is crucial to the validity of testing of real-time systems. However, computer architecture designs fail to deliver repeatable timing, a consequence of aggressive techniques that improve average-case performance. This paper introduces the Precision-Timed ARM (PTARM), a precision-timed (PRET) microarchitecture implementation that exhibits repeatable execution times without sacrificing performance. The PTARM employs a repeatable thread-interleaved pipeline with an exposed memory hierarchy, including a repeatable DRAM controller. Our benchmarks show an improved throughput compared to a single-threaded in-order five-stage pipeline, given sufficient parallelism in the software.

  • 31.
    Jonsson, Leif
    et al.
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Broman, David
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Sandahl, Kristian
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Eldh, Sigrid
    Karlstads Universitet, Sweden.
    Towards Automated Anomaly Report Assignment in Large Complex Systems using Stacked Generalization2012In: Software Testing, Verification and Validation (ICST), 2012, IEEE , 2012, 437-446 p.Conference paper (Refereed)
    Abstract [en]

    Maintenance costs can be substantial for organizations with very large and complex software systems. This paper describes research for reducing anomaly report turnaround time which, if successful, would contribute to reducing maintenance costs and at the same time maintaining a good customer perception. Specifically, we are addressing the problem of the manual, laborious, and inaccurate process of assigning anomaly reports to the correct design teams. In large organizations with complex systems this is particularly problematic because the receiver of the anomaly report from customer may not have detailed knowledge of the whole system. As a consequence, anomaly reports may be wrongly routed around in the organization causing delays and unnecessary work. We have developed and validated machine learning approach, based on stacked generalization, to automatically route anomaly reports to the correct design teams in the organization. A research prototype has been implemented and evaluated on roughly one year of real anomaly reports on a large and complex system at Ericsson AB. The prediction accuracy of the automation is approaching that of humans, indicating that the anomaly report handling time could be significantly reduced by using our approach.

  • 32. Norling, Kristoffer
    et al.
    Broman, David
    Linköping University, Department of Computer and Information Science.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science.
    Siemers, Alexander
    Linköping University, Department of Computer and Information Science.
    Fritzson, Dag
    Linköping University, Department of Computer and Information Science.
    Secure Distributed Co-Simulation over Wide Area Networks2007Conference paper (Other academic)
    Abstract [en]

    Modeling and simulation often require different tools for specialized purposes, which increase the motivation to use co-simulation. Since physical models often are describing enterprises¿ primary know-how, there is a need for a sound approach to securely perform modeling and simulation. This paper discusses different possibilities from a security perspective, with focus on secure distributed co-simulation over wide area networks (WANs), using transmission line modeling (TLM). An approach is outlined and performance is evaluated both in a simulated WAN environment, and for a real encrypted co-simulation between Sweden and Australia. It is concluded that several parameters affect the total simulation time, where especially the network delay (latency) has a significant impact.

  • 33.
    Vasilevskaya, Maria
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Broman, David
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Sandahl, Kristian
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    An Assessment Model for Large Project Courses2014In: Proceedings of the 45th ACM Technical Symposium on Computer Science Education (SIGCSE), Association for Computing Machinery (ACM), 2014Conference paper (Refereed)
    Abstract [en]

    Larger project courses, such as capstone projects, are essential in a modern computing curriculum. Assessing such projects is, how- ever, extremely challenging. There are various aspects and trade-offs of assessments that can affect the quality of a project course. Individual assessments can give fair grading of individuals, but may loose focus of the project as a group activity. Extensive teacher involvement is necessary for objective assessment, but may affect the way students are working. Continuous feedback to students can enhance learning, but may be hard to combine with fair assessment. Most previous work is focusing on some specific assessment aspect, whereas we in this paper present an assessment model that consists of a collection of assessment activities, each covering different aspects. We have applied, developed, and improved these activities during a six-year period and evaluated their usefulness by performing a questionnaire-based survey.

  • 34.
    Vasilevskaya, Maria
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Broman, David
    KTH Royal Institute of Technology, Stockholm, Sweden; University of California, Berkeley, USA.
    Sandahl, Kristian
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Assessing Large Project Courses: Model, Activities, and Lessons Learned2015In: ACM Transactions on Computing Education, ISSN 1946-6226, E-ISSN 1946-6226, Vol. 15, no 4, 20:1-20:30 p.Article in journal (Refereed)
    Abstract [en]

    In a modern computing curriculum, large project courses are essential to give students hands-on experience of working in a realistic software engineering project. Assessing such projects is, however, extremely challenging. There are various aspects and tradeoffs of assessments that can affect the course quality. Individual assessments can give fair grading of individuals, but may loose focus of the project as a group activity. Extensive teacher involvement is necessary for objective assessment, but may affect the way students are working. Continuous feedback to students can enhance learning, but may be hard to combine with fair assessment. Most previous work is focusing on some specific assessment aspect, whereas we in this paper present an assessment model that consists of a collection of assessment activities, each covering different aspects. We have applied, developed, and improved these activities during a seven-year period. To evaluate the usefulness of the model, we perform questionnaire-based surveys over a two-years period. Furthermore, we design and execute an experiment that studies to what extent students can perform fair peer assessment and to what degree the assessments of students and teachers agree. We analyze the results, discuss findings, and summarize lessons learned.

1 - 34 of 34
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