preemptively scheduling a set of independent jobs with release time on one processor is a historical problem. in this paper, the same problem has been considered in which objective is to minimize the mean flow time. to prepare a perfect branch-and-bound, some optimality conditions have been represented and they have been compared with the optimality conditions which have been proposed before. o...

Combining linear programming approach with the Plotkin-Johnson argument for constant weight codes, we derive upper bounds on the size of codes of length n and minimum distance d = (n j)=2, 0 < j < n 1=3 . For j = o(n 1=3 ) these bounds practically coincide (are slightly better) with the Tietav ainen bound. For xed j and j proportional to n 1=3 , j < n 1=3 (2=9) lnn, it improves on the earlier...

We currently know the following four bounds on rate as a function of relative distance, three of them upper bounds (which tell us what rate-distance combinations are impossible), and one lower bound (which tells us what rate-distance combinations we can achieve). In the following, R is the rate and δ the relative distance of a code. For example, a (n, k, d) code has R = k/n and δ = d/n. Hq(x) i...

we consider the queueing maximal covering location-allocation problem (qm-clap) with an m/m/1 queueing system. we propose a new solution procedure based on decomposition of the problem into smaller sub-problems. we solve the resulting sub-problems both with a branch and bound algorithm and with the meta-heuristic grasp. we also solve the entire model with grasp. computational results for these ...

In this article I present a novel approach to integrated ground and air public transport journey planning, operating at continent scale. Flexible date search, prerequisite for long distance trips given their typical low and irregular service frequencies, is core functionality. The algorithm, best described as timed branch-and-bound (BBtime), is especially suited for irregular and poorly structu...

A spherical τ -design on S is a finite set such that, for all polynomials f of degree at most τ , the average of f over the set is equal to the average of f over the sphere S. In this paper we obtain some necessary conditions for the existence of designs of odd strengths and cardinalities. This gives nonexistence results in many cases. Asymptotically, we derive a bound which is better than the ...

In this paper, the problem of two-machine flow shop scheduling to minimize total energy costs under time-of-use tariffs is investigated. As the objective function of this study is not a regular measure, allowing intentional idle-time can be advantageous. So this study considers two approaches, one for non-delay version of the problem and the other one for a situation when inserting intentional ...

This paper summarizes work on a General Branch and Bound formulation which includes previous formulations as special cases and provides a unified approach to understanding most heuristic search procedures developed in A.I. for Pattern Analysis University of Maryland, College Park, MD 20742