The single machine sequencing problem is considered in which there are precedence constraints on the jobs. The objective is to minimize the sum of weighted completion times. A lower bound is obtained by successively performing a Lagrangean relaxation of appropriate constraints. Each Lagrange...

We consider the node clustering problem that arises in designing a survivable two-level telecommunication network. The problem simultaneously determines an optimal partitioning of the whole network into clusters (local networks) and hub locations in each cluster. Intercluster traffic...

Cadaveric liver transplantation is the only viable therapy for end-stage liver disease patients without a living donor. However, this type of transplantation is hindered in the United States by donor scarcity and rapid viability decay. Given these difficulties, the current U.S. liver allocation...

Redistricting, the redrawing of congressional district boundaries within the states, may occur every 10 years on the basis of the population census. Many redistricting plans are designed with partisan politics in mind, resulting in disputes and forcing judges to intervene. We address this...

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...