1. Statistics and Operations Research Department, Tel Aviv University, Tel Aviv, Israel.
2. Department of Mathematics and Computer Science, The Open University of Israel, Raanana, Israel. Current address: Department of Computer Science, University of Haifa, Haifa, Israel.
3. Department of Mathematics and Computer Science, The Open University of Israel, Raanana, Israel. Current address: Department of Computer Science and Automation, Indian Institute of Science, Bengaluru, India.