We consider the problem of scheduling a set of n jobs on m identical parallel machines so as to minimize the weighted sum of job completion times. This problem is NP-hard in the strong sense. The best approximation result known so far was a 1/2(1 + √2)-approximation algorithm that has been...

One of the most popular lottery games worldwide is the so-called “lotto k/N”. It considers N numbers 1,2,…,N from which k are drawn randomly, without replacement. A player selects k or more numbers and the first prize is shared amongst those players whose selected numbers match all of the...

A production system which consists of a number of parallel assembly lines is considered. On each line a certain product is manufactured observing a common cycle time. By arranging the lines in a favourable manner, it is possible to increase efficiency of the production system by combining...

Assembly line balancing problems (ALBP) arise whenever an assembly line is con- figured, redesigned or adjusted. An ALBP consists of distributing the total workload for manu- facturing any unit of the products to be assembled among the work stations along the line sub- ject to a strict or...