objectives: this study was designed to assess the changes of the mandible of patients who underwent orthodontic treatment with or without extraction of four premolars. materials and methods: eighteen class i bimaxillary protrusion patients treated with extraction of four first premolars and retraction of anterior teeth and 18 class i non-extraction patients with a mean age of 16.38±0.4 years we...

This paper considers a multi-period, multi-product inventory-routing problem in a two-level supply chain consisting of a distributor and a set of customers. This problem is modeled with the aim of minimizing bi-objectives, namely the total system cost (including startup, distribution and maintenance costs) and risk-based transportation. Products are delivered to customers by some heterogeneous ...

[1] corresponding author e-mail: [email protected]   [1] corresponding author e-mail: [email protected]   lot-sizing problems (lsps) belong to the class of production planning problems in which the availability quantities of the production plan are always considered as a decision variable. this paper aims at developing a new mathematical model for the multi-level capacitated lsp w...

The redundancy allocation is one of the most important and useful problems in system optimization, especially in electrical and mechanical systems. The object of this problem is to maximize system reliability or availability within a minimum operation cost. Many works have been proposed in this area so far to draw the problem near to real-world situations. While in classic models the system com...

We study a new class of online learning problems where each of the online algorithm’s actions is assigned an adversarial value, and the loss of the algorithm at each step is a known and deterministic function of the values assigned to its recent actions. This class includes problems where the algorithm’s loss is the minimum over the recent adversarial values, the maximum over the recent values,...

Chvv atal (1980) describes a class of zero-one knapsack problems provably diicult for branch and bound and dynamic programming algorithms. Chung et al. (1988) identiies a class of integer knapsack problems hard for branch and bound algorithms. We show that for both classes of problems local search provides optimal solutions quickly.

  In this paper flexible job-shop scheduling problem (FJSP) is studied in the case of optimizing different contradictory objectives consisting of: (1) minimizing makespan, (2) minimizing total workload, and (3) minimizing workload of the most loaded machine. As the problem belongs to the class of NP-Hard problems, a new hybrid genetic algorithm is proposed to obtain a large set of Pareto-optima...