1. Komatsu Ltd., 2-3-6, Akasaka, Minato-ku, Tokyo 107-8414, Japan
2. Department of Physics, Umeå University, SE-901 87 Umeå, Sweden
3. Department of Mathematics and Computer Science, Karlstad University, SE-651 88 Karlstad, Sweden
4. Department of Computing Science, Umeå University, SE-901 87 Umeå, Sweden
5. Algoryx Simulation AB, Kuratorvägen 2B, SE-907 36 Umeå, Sweden