Semidefinite programming based approaches to home-away assignment problems in sports scheduling

For a given schedule of a round-robin tournament and a matrix of distances between homes of teams, an optimal home-away assignment problem is to find a home-away assignment that minimizes the total traveling distance. We propose a technique to transform the problem to MIN RES CUT. We apply Goemans and Williamson’s 0.878-approximation algorithm for MAX RES CUT, which is based on a positive semidefinite programming relaxation, to the obtained MIN RES CUT instances. Computational experiments show that our approach quickly generates solutions of good approximation ratios.Access: via WW

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The Home-Away Assignment Problems and Break Minimization/Maximization Problems in Sports Scheduling

Suppose that we have a timetable of a round-robin tournament with a number of teams, and distances among their homes. The home-away assignment problem is to find a home-away assignment that minimizes the total traveling distance of the teams. This paper also deals with the break minimization (maximization) problem, which finds a home-away assignment that minimizes (maximizes) the number of breaks, i.e., the number of occurrences of consecutive matches held either both at away or both at home for a team. Part of this aim of this paper is to give a unified view to the three problems, the break minimization/maximization problems and the home-away assignment problem. We see that optimal solutions of the break minimization/maximization problems are obtained by solving the home-away assignment problem. For the home-away assignment problem, we propose a formulation as an integer program, and some rounding algorithms. We also provide a technique to transform the home-away assignment problem to MIN RES CUT and apply Goemans and Williamson\u27s algorithm for MAX RES CUT, which is based on a positive semidefinite programming relaxation, to the obtained MIN RES CUT instances. Computational experiments show that our approaches quickly generate solutions of good approximation rations

Heparin as Bridging Anticoagulant and Antiplatelet Therapy during the Perioperative Period

Anticoagulant and antiplatelet medications are commonly used for the treatment and prevention of cardiovascular diseases. We studied 84 patients who received heparin as a bridging anticoagulant and antiplatelet therapy during the perioperative period. Hospitalization was extended for adjusting anticoagulant and antiplatelet drugs and also bleeding complications in the perioperative period. There were 25 instances of bleeding complications (29.7%) in this study. These complications mainly occurred when anticoagulant and antiplatelet medications were restarted in the postoperative period. In transurethral surgery, patients taking warfarin and antiplatelet drugs (aspirin or ticlopidine) had a statistically significant increase in bleeding complications compared to patients taking warfarin alone. We compared 51 cases of transurethral resection of bladder tumor, transurethral resection of the prostate holium laser enucleation of the prostate, nephroureterectomy and percutaneous nephrolithotomy with heparinization were compared to 692 cases with no heparinization. The heparinization group had a statistically significant longer hospitalization period and an increase in bleeding complications. There was one instance of thromboembolism (1.2%) in our series. This involved stent thrombosis of a patient who had drug-eluting stent in the left anterior descending coronary artery. She died three days postoperatively. The number of patients taking anticoagulant and/or antiplatelet drugs is predicted to increase in the future due to aging of the population. Guidelines for the management of anticoagulant and antiplatelet therapy in the urological period are considered necessary

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博士（法学）thesi