We consider the problem of preemptive scheduling n jobs on two uniform parallel machines. All jobs have equal processing requirements. For each job we are given its due date. The objective is to find a schedule minimizing total tardiness ∑Ti. We suggest an O(nlogn) algorithm to solve this problem.

In this paper we consider problems of the following type: Let E = { e 1 , e 2 ,..., e n } be a finite set and $${\mathcal {F}}$$ be a family of subsets of E. For each element e i in E, c i is a given capacity and $${\mathcal {w}}$$ i is the cost of increasing capacity c i by one unit. It is...

In this paper we consider problems of the following type: Let E = { e <Subscript>1</Subscript>, e <Subscript>2</Subscript>,..., e <Subscript> n </Subscript> } be a finite set and <InlineEquation ID="IEq1"> <EquationSource Format="TEX">$${\mathcal {F}}$$</EquationSource> </InlineEquation> be a family of subsets of E. For each element e <Subscript> i </Subscript> in E, c <Subscript> i </Subscript> is a given capacity and <InlineEquation ID="IEq7"> <EquationSource Format="TEX">$${\mathcal {w}}$$</EquationSource> </InlineEquation> <Subscript> i </Subscript> is the cost of increasing capacity c <Subscript> i </Subscript> by one...</subscript></subscript></equationsource></inlineequation></subscript></subscript></equationsource></inlineequation></subscript></subscript></subscript>

An inverse optimization problem is defined as follows. Let S denote the set of feasible solutions of an optimization problem P, let c be a specified cost (capacity) vector, and x0 ∈ S. We want to perturb the cost (capacity) vector c to d so that x0 is an optimal solution of P with respect to...

We describe a new dual algorithm for the minimum cost flow problem. It can be regarded as a variation of the best known strongly polynomial minimum cost flow algorithm, due to Orlin. Indeed we obtain the same running time of O(m log m(m+n log n)), where n and m denote the number of vertices and...