We propose a parallel algorithm for computing exact solutions to the problem of minimizing the number of multileaf collimator apertures needed in step-and-shoot intensity modulated radiotherapy. These problems are very challenging particularly as the problem size increases. Here, we investigate...

The task allocation problem (TAP) is one where a number of tasks or modules need to be assigned to a set of processors or machines at minimum overall cost. The overall cost includes the communication cost between tasks that are assigned to different processors and other costs such as the...

In this paper, we introduce five classes of new valid cutting planes for the precedence-constrained (PC) and/or time-window-constrained (TW) Asymmetric Travelling Salesman Problems (ATSPs) and directed Vehicle Routing Problems (VRPs). We show that all five classes of new inequalities are...

In this paper, we introduce five classes of new valid cutting planes for the precedence-constrained (PC) and/or time-window-constrained (TW) Asymmetric Travelling Salesman Problems (ATSPs) and directed Vehicle Routing Problems (VRPs). We show that all five classes of new inequalities are...

This paper develops a decision framework for environmental philanthropy in search of achieving sustainability on a crowded planet. Many of the world's most pressing global challenges are environmental in nature (or have stark environmental implications) and require long-term efforts. Asking what...

This paper analyzes how to create leverage in philanthropy. A strategic approach to designing programs or selecting grantees is often a necessary condition for leverage, identifying the intervention that creates the greatest positive impact at a given level of social investment. How can one...