Håkan Lundvall

OpenModelica - A free open-source environment for system modeling, simulation, and teaching

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.

Automatic parallelization of simulation code for equation-based models with software pipelining and measurements on three platforms

In this work we report results from a new integrated method of automatically generating parallel code from Modelica models by combining parallelization at two levels of abstraction. Performing inline expansion of a Runge-Kutta solver combined with fine-grained automatic parallelization of the right-hand side of the resulting equation system opens up new possibilities for generating high performance code, which is becoming increasingly relevant when multi-core computers are becoming commonplace. An implementation, in the form of a backend module for the OpenModelica compiler, has been developed and used for measurements on two architectures: Intel Xeon and SGI Altix 3700 Bx2. This paper also contains some very recent results of a prototype implementation of this parallelization approach on the Cell BE processor architecture.

Automatic parallelization of object oriented models executed with inline solvers

In this work we report preliminary results of automatically generating parallel code from equation-based models together at two levels: Performing inline expansion of a Runge-Kutta solver combined with fine-grained automatic parallelization of the resulting RHS opens up new possibilities for generating high performance code, which is becoming increasingly relevant when multicore computers are becoming common-place. We have introduced a new way of scheduling the task graph generated from the simulation problem which utilizes knowledge about locality of the simulation problem.

Vision system for monitoring the production of corrugated cardboard

In this paper a vision system for the control quality in a factory of corrugated cardboard is described. The problem under study is the automatic detection and monitoring of the sheets of cardboard constituting a unit of sale. A precise measurement of the number of sheets is a difficult task, since, during the process, some sheets must be discarded, because of their inferior quality, or because they have been damaged during the transport. Usually, the number of the sheets is estimated from the ratio between the weight of the unit and the nominal weight of a single sheet. Since the weight of a sheet is uncertain, an estimation based on the weight ratio is poor and its reliability is very low. A different solution is proposed in this paper: it estimates the number of the sheets via a suitable vision system. It offers a very high precision (the middle error is smaller of 2%) and it has the advantages to avoid invasive interactions with the process of production and to be a low cost solution.