1. Sitael S.p.A., Via Gherardesca 5, Pisa 56121, Italy e-mail:
2. Department of Industrial and Civil Engineering, University of Pisa, Via Gerolamo Caruso 8, Pisa 56122, Italy e-mail:
3. GMYS-Space, Via di Broccoletto, Lucca 55100, Italy e-mail:
4. Sitael S.p.A., Via Gherardesca 5 Pisa 56121, Italy e-mail: