The OpenModelica integrated environment for modeling, simulation, and model-based development

OpenModelica is a unique large-scale integrated open-source Modelica- and FMI-based modeling, simulation, optimization, model-based analysis and development environment. Moreover, the OpenModelica environment provides a number of facilities such as debugging; optimization; visualization and 3D animation; web-based model editing and simulation; scripting from Modelica, Python, Julia, and Matlab; efficient simulation and co-simulation of FMI-based models; compilation for embedded systems; Modelica- UML integration; requirement verification; and generation of parallel code for multi-core architectures. The environment is based on the equation-based object-oriented Modelica language and currently uses the MetaModelica extended version of Modelica for its model compiler implementation. This overview paper gives an up-to-date description of the capabilities of the system, short overviews of used open source symbolic and numeric algorithms with pointers to published literature, tool integration aspects, some lessons learned, and the main vision behind its development.Fil: Fritzson, Peter. Linköping University; SueciaFil: Pop, Adrian. Linköping University; SueciaFil: Abdelhak, Karim. Fachhochschule Bielefeld; AlemaniaFil: Asghar, Adeel. Linköping University; SueciaFil: Bachmann, Bernhard. Fachhochschule Bielefeld; AlemaniaFil: Braun, Willi. Fachhochschule Bielefeld; AlemaniaFil: Bouskela, Daniel. Electricité de France; FranciaFil: Braun, Robert. Linköping University; SueciaFil: Buffoni, Lena. Linköping University; SueciaFil: Casella, Francesco. Politecnico di Milano; ItaliaFil: Castro, Rodrigo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Investigación en Ciencias de la Computación. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Investigación en Ciencias de la Computación; ArgentinaFil: Franke, Rüdiger. Abb Group; AlemaniaFil: Fritzson, Dag. Linköping University; SueciaFil: Gebremedhin, Mahder. Linköping University; SueciaFil: Heuermann, Andreas. Linköping University; SueciaFil: Lie, Bernt. University of South-Eastern Norway; NoruegaFil: Mengist, Alachew. Linköping University; SueciaFil: Mikelsons, Lars. Linköping University; SueciaFil: Moudgalya, Kannan. Indian Institute Of Technology Bombay; IndiaFil: Ochel, Lennart. Linköping University; SueciaFil: Palanisamy, Arunkumar. Linköping University; SueciaFil: Ruge, Vitalij. Fachhochschule Bielefeld; AlemaniaFil: Schamai, Wladimir. Danfoss Power Solutions GmbH & Co; AlemaniaFil: Sjolund, Martin. Linköping University; SueciaFil: Thiele, Bernhard. Linköping University; SueciaFil: Tinnerholm, John. Linköping University; SueciaFil: Ostlund, Per. Linköping University; Sueci

Vorschlag für neue objektorientierte gleichungsbasierte Modellbibliotheken für thermodynamische Systeme

This thesis proposes two new model libraries for fluid properties and for components that can be used for the simulation of thermodynamic systems such as refrigeration, air-conditioning, and heat-pump systems. The new fluid property library is written in C/C++ and can be interfaced from various software tools and programming languages. The new component model library is written in the object-oriented equation-based modeling language Modelica. Furthermore, tools for the automated generation of class diagrams and the visualization of the solution process as well as the numerical results in relevant diagrams are presented. Both new libraries are based on a thorough object-oriented analysis. A set of general design rules for the development of object-oriented component model libraries is formulated to ensure that the resulting library can be used by the entire spectrum of possible users from experienced developers to design engineers. The new object-based fluid property library is based on a generalized approach to include external fluid property computation codes in Modelica. It is simple to extend to additional external fluid property computation codes. It allows for a numerically efficient handling of fluid properties in Modelica and in a number of software tools. The new model library for components and systems was developed based on the newly introduced design rules. It features a structure that is simple to understand and flexible to allow for extensions. All balance equations are formulated in an easy and comprehensible way in base components. The new component model library contains models with different levels of detail to allow for a problem-dependent model selection. Two applications are presented to demonstrate the capabilities of the two new libraries and to demonstrate their extendibility and multidisciplinarity.Diese Arbeit beschreibt zwei neue Modellbibliotheken mit Stoffdaten- und Komponentenmodellen zur Simulation thermodynamischer Systeme wie zum Beispiel Kälteanlagen, Klimaanlagen und Wärmepumpen. Die neue Stoffdatenbibliothek ist basierend auf C/C++ entwickelt worden und verfügt über Schnittstellen für unterschiedliche Anwendungsprogramme und Programmiersprachen. Die neue Komponentenbibliothek ist in der objektorientierten gleichungsbasierten Modellierungssprache Modelica geschrieben. Es werden außerdem Werkzeuge vorgestellt, die die automatische Generierung von Klassenstrukturdiagrammen und die Visualisierung des Lösungsprozesses sowie der numerischen Ergebnisse in thermodynamischen Diagrammen ermöglichen. Beide neuen Bibliotheken basieren auf einer gründlichen objektorientierten Analyse. Es werden des Weiteren allgemeingültige Richtlinien für die Erstellung von objektorientierten Modellbibliotheken entwickelt, die sicherstellen, dass die entwickelte Bibliothek das gesamte Spektrum möglicher Benutzer vom Code-Entwickler bis hin zum Anwender unterstützt. Die neue objektbasierte Stoffdatenbibliothek basiert auf einem generalisierten Ansatz zur Einbindung externer Stoffdatenbibliotheken in Modelica. Der beschriebene Ansatz lässt sich einfach auf weitere externe Bibliotheken zur Stoffdatenberechnung erweitern. Er erlaubt die numerisch effektive Behandlung der eingebundenen Bibliotheken in Modelica sowie in Anwendungsprogrammen. Die neue Modellbibliothek für Komponenten und Systeme verfügt über eine Struktur, die einfach verständlich und flexibel erweiterbar ist. Alle Erhaltungsgleichungen sind in einfach verständlicher Form in Basiskomponenten formuliert. Die neue Komponentenmodellbibliothek enthält Modelle unterschiedlicher Modellierungstiefe, um eine problemabhängige Auswahl von Modellen zu erlauben. Zwei Anwendungen für die beiden neuen Modellbibliotheken werden präsentiert, um die Erweiterbarkeit und die Multidisziplinarität der neuen Bibliotheken zu demonstrieren

Computer algebra techniques in object-oriented mathematical modelling.

This thesis proposes a rigorous object-oriented methodology, supported by computer algebra software, to generate and relate features in a mathematical model. Evidence shows that there is little heuristic or theoretical research into this problem from any of the three principal modelling methodologies: 'case study’, ‘scenario’ and ‘generic’. This thesis comprises two other major strands: applications of computer algebra software and the efficacy of symbolic computation in teaching and learning. Developing the principal algorithms in computer algebra has sometimes been done at the expense of ease of use. Developers have also not concentrated on integrating an algebra engine into other software. A thorough review of quantitative studies in teaching and learning mathematics highlights a serious difficulty in measuring the effect of using computer algebra. This arises because of the disparate nature of learning with and without a computer. This research tackles relationship formulation by casting the problem domain into object-oriented terms and building an appropriate class hierarchy. This capitalises on the fact that specific problems are instances of generic problems involving prototype physical objects. The computer algebra facilitates calculus operations and algebraic manipulation. In conjunction, I develop an object-oriented design methodology applicable to small-scale mathematical modelling. An object model modifies the generic modelling cycle. This allows relationships between features in the mathematical model to be generated automatically. The software is validated by quantifying the benefits of using the object-oriented techniques, and the results are statistically significant. The principal problem domain considered is Newtonian particle mechanics. Although the Newtonian axioms form a firm basis for a mathematical description of interactions between physical objects, applying them within a particular modelling context can cause problems. The goal is to produce an equation of motion. Applications to other contexts are also demonstrated. This research is significant because it formalises feature and equation-generation in a novel way. A new modelling methodology ensures that this crucial stage in the modelling cycle is given priority and automated

Foundations of Multi-Paradigm Modelling for Cyber-Physical Systems

This open access book coherently gathers well-founded information on the fundamentals of and formalisms for modelling cyber-physical systems (CPS). Highlighting the cross-disciplinary nature of CPS modelling, it also serves as a bridge for anyone entering CPS from related areas of computer science or engineering. Truly complex, engineered systems—known as cyber-physical systems—that integrate physical, software, and network aspects are now on the rise. However, there is no unifying theory nor systematic design methods, techniques or tools for these systems. Individual (mechanical, electrical, network or software) engineering disciplines only offer partial solutions. A technique known as Multi-Paradigm Modelling has recently emerged suggesting to model every part and aspect of a system explicitly, at the most appropriate level(s) of abstraction, using the most appropriate modelling formalism(s), and then weaving the results together to form a representation of the system. If properly applied, it enables, among other global aspects, performance analysis, exhaustive simulation, and verification. This book is the first systematic attempt to bring together these formalisms for anyone starting in the field of CPS who seeks solid modelling foundations and a comprehensive introduction to the distinct existing techniques that are multi-paradigmatic. Though chiefly intended for master and post-graduate level students in computer science and engineering, it can also be used as a reference text for practitioners

Modelação de sistemas hidráulicos para simulação com hardware-in-the-loop

Doutoramento em Engenharia MecânicaUm ambiente simulado é a via mais rápida, e de menores custos, para avaliar o desempenho de diferentes estratégias para controlo de sistemas hidráulicos. Neste campo emerge uma nova técnica, denominada simulação com hardware-in-the-loop (HILS), para teste de controladores reais em ambientes virtuais simulados em tempo real. A presente dissertação propõe uma metodologia para a organização de bibliotecas de modelos, um conjunto de modelos híbridos semi-empíricos para componentes de sistemas hidráulicos e uma plataforma para a realização de experiências de simulação com hardware-in-the-loop. A metodologia proposta baseia-se na associação de uma nova linguagem de modelação orientada por objectos, chamada Modelica, para a descrição da estrutura dos modelos, com o formalismo gráfico dos Statecharts para a descrição do seu comportamento híbrido. Tendo em vista a concretização da metodologia, foi desenvolvida uma biblioteca de modelos para a implementação do formalismo dos Statecharts em Modelica. Entre os modelos para componentes hidráulicos propostos está um conjunto de modelos semi-empíricos para a modelação de válvulas proporcionais de elevado desempenho. Os modelos desenvolvidos usam dados do fabricante ou dados experimentais para ajuste dos parâmetros, de forma a reproduzir as características estáticas (ganho de pressão, caudal de fugas e ganho de caudal) e dinâmicas (resposta em frequência) da válvula. Foi construída uma plataforma para teste do desempenho dos modelos híbridos desenvolvidos em simulações com hardware-in-the-loop. A plataforma é composta por um manipulador com actuação hidráulica equipado com um conjunto de transdutores, por hardware de tempo real e por um conjunto de ferramentas de software para aquisição de dados e controlo. De um conjunto de experiências HILS, realizadas com diferentes núcleos de tempo real, foram obtidos resultados muito promissores para os modelos semi-empíricos propostos.A simulated environment is the less expensive and fastest way of evaluating the relative merits of different control schemes for a given hydraulic system. A new technique, called hardware-in-the-loop simulation (HILS), is emerging to test hardware controllers in virtual environments simulated in real time. This thesis proposes a methodology to organize model libraries, a set of semiempirical hybrid models for hydraulic components and a platform for hardwarein- the-loop simulation experiments. The methodology holds in the association of a new object oriented modelling language, called Modelica, to describe model structure, with the Statecharts graphical formalism to describe its hybrid behaviour. In order to implement the proposed methodology, a new Statecharts library in Modelica was developed. Among the proposed hydraulic component models there is a set of new semiempirical models for high performance proportional valves. The developed models use either data sheet or experimental values to fit the model parameters in order to reproduce both static (pressure gain, leakage flow rate and flow gain) and dynamic (frequency response) valve characteristics. An experimental platform was setup to test the developed hybrid models performance in hardware-in-the-loop simulation experiments. The platform is composed by a hydraulic actuated manipulator with a set of sensors, by real time hardware and by a package of software tools for data acquisition and control. Very satisfactory results, from a set of HILS experiments performed in different real time kernels were obtained for the semi-empirical models proposed

ObjectMath – An Object-Oriented Language and Environment for Symbolic and Numerical Processing in Scientific Computing

ObjectMath is a language for scientific computing that integrates object-oriented constructs with features for symbolic and numerical computation. Using ObjectMath, complex mathematical models may be implemented in a natural way. The ObjectMath programming environment provides tools for generating efficient numerical code from such models. Symbolic computation is used to rewrite and simplify equations before code is generated. One novelty of the ObjectMath approach is that it provides a comman language and an integrated environment for this kind of mixed symbolic/numerical computation. The motivation for this work is the current low-level state of the art in programming for scientific computing. Much numerical software is still being developed the traditional way in Fortran. This is especially true in application areas such as machine elements analysis, where complex nonlinear problems are the norm. We believe that tools like ObjectMath can increase productivity and quality, thus enabling users to solve problems that are too complex to handle with traditional tools

Database Web Programming

This book is the result of teaching the laboratory component of an introductory course in Database Systems in the Department of Computer Science & Software Engineering, Concordia University, Montreal.. The intent of this part of the course was to have the students create a practical web-based application wherein the database forms the dynamic component of a real life application using a web browser as the user interface. It was decided to use all open source software, namely, Apache web server, PHP, JavaScript and HTML, and also the open source database which started as MySQL and has since migrated to MariaDB. The examples given in this book have been run successfully both using MySQL on a Windows platform and MariaDB on a Linux platform without any changes. However, the code may need to be updated as the underlying software systems evolve with time, as functions are deprecated and replaced by others. Hence the user is responsible for making any required changes to any code given in this book. The readers are also warned of the changing privacy and data usage policy of most web sites. They should be aware that most web sites collect and mine user’s data for private profit. The authors wish to acknowledge the contribution of many students in the introductory database course over the years whose needs and the involvement of one of the authors in the early days of the web prompted the start of this project in the late part of the 20th century. This was the era of the dot com bubble. The corporations that survived this bubble have grown, thanks to data and its mining, to become the most powerful monopolies in the history of mankind. It is hoped that the open source community will replace these with locally controlled alternatives