In this research we tackle the scheduling problem in additive manufacturing for unrelated parallel machines. Both nesting and aspects are considered. Parts have several alternative build orientations. The goal is to minimize total tardiness of parts. We propose a mixed-integer linear programming model which considers subproblem as 2D bin-packing problem, well simplifies 1D problem. computationa...

The dynamic response of power grids to small disturbances influences their overall stability. This letter examines the effect network topology on linearized time-invariant dynamics electric systems. proposed framework utilizes H 2 -norm based sta...

Background: Urban air pollutants may affect respiratory mortality. This study was conducted to investigate this effect in Ahvaz, one of the most polluted cities in the world. Methods: The impact of 7 major air pollutants including O3, PM10, NO2, CO, and SO2 were evaluated on respiratory mortality in different gender and age groups using a quasi-Poisson, second degree polynomial constrained, di...

Scheduling in a permutation flowshop refers to processing of jobs set available machines the same order. Among several possible performance characteristics flowshop, makespan remains one highest preferred metrics by researchers past six decades. The constructive heuristic proposed Nawaz-Enscore-Ham (NEH) is best for minimization. essentially depends on initial ordering according particular prio...

Many inequalities for Mixed-Integer Linear Programs (MILPs) or pure Integer Linear Programs (ILPs) are derived from the Gomory corner relaxation, where all the nonbinding constraints at an optimal LP vertex are relaxed. Computational results show that the corner relaxation gives a good approximation of the integer hull for problems with general-integer variables, but the approximation is less s...

Total weighted tardiness is a measure of customer satisfaction. Minimizing it represents satisfying the general requirement of on-time delivery. In this research, we consider an ant colony optimization (ACO) algorithm to solve the problem of scheduling unrelated parallel machines to minimize total weighted tardiness. The problem is NP-hard in the strong sense. Computational results show that th...

Four heuristic algorithms are developed for solving the generalized version of tardiness flow shop problems. We consider the generalized tardiness flow shop model with minimization of the total tardiness as its performance measure. We modify the concept of cost over time (COVERT) for the generalized version of the flow shop tardiness model and employ this concept for developing four algorithms....

We consider a box model of the thermohaline circulation with mixed boundary conditions in which advective processes are incorporated via an explicit time delay mechanism. The pipes which connect the subtropical and subpolar boxes have a nite volume and do not interact with the atmosphere or with the rest of the ocean except for channeling uxes between the subtropical and subpolar regions. The c...