118 research outputs found
Dynamic programming algorithms and Lagrangian lower bounds for a discrete lot streaming problem in a two-machine flow shop
Get PDFIn this paper, we propose exact and heuristic solution approaches based on dynamic programming for an open lot streaming problem. We also present the first application of Lagrangian relaxation to compute strong lower bounds to such a problem. The application concerns the minimization of the total flow time for the discrete version of a single-job lot streaming problem from the literature in a two-machine flow shop with attached setup times. Computational results on benchmark instances illustrate the effectiveness of the proposed approaches and give evidence of the strength of the Lagrangian relaxation lower bounds
An iterated dynasearch algorithm for the single-machine total weighted tardiness scheduling problem
No full textThis paper introduces a new neighborhood search technique, called dynasearch, that uses dynamic programming to search an exponential size neighborhood in polynomial time. While traditional local search algorithms make a single move at each iteration, dynasearch allows a series of moves to be performed. The aim is for the lookahead capabilities of dynasearch to prevent the search from being attracted to poor local optima. We evaluate dynasearch by applying it to the problem of scheduling jobs on a single machine to minimize the total weighted tardiness of the jobs. Dynasearch is more effective than traditional first-improve or best-improve descent in our computational tests. Furthermore, this superiority is much greater for starting solutions close to previous local minima. Computational results also show that an iterated dynasearch algorithm in which descents are performed a few random moves away from previous local minima is superior to other known local search procedures for the total weighted tardiness scheduling problem
Leading Damen Workboats Toward an Optimal Sourcing Strategy to Maximize the Cost Efficiency of Purchasing
No full textThe effect of policy on the incorporation of sustainability in cleaning tenders of the RIS
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