In today’s competitive market place, companies seek an efficient structure of supply chain so as to provide customers with highest value and achieve competitive advantage. This requires a broader perspective than just the borders of an individual company during a supply chain. This paper investigates an aggregate production planning problem integrated with distribution issues in a supply chain ...

In this paper, we consider the M/G/k queueing system with setup times. This particular queueing model is common in manufacturing systems, where idle machines are turned off to save on operating costs, as well as in server farms, where idle servers are turned off to conserve power. While recent literature has analyzed the M/M/k system with exponential setup times, no closedform solutions were ob...

In this paper we consider the problem of scheduling jobs on parallel machines with setup times. The setup has to be performed by a single server. The objective is to minimize the schedule length (makespan) as well as the forced idle time. The makespan problem is known to be NP -hard even for the case of two identical parallel machines. This paper presents a pseudopolynomial algorithm for the ca...

BACKGROUND Question design can influence the validity and reliability of physical activity (PA) self-report instruments. This study assesses the effect of temporal domain ("days" walked versus "times" walked) on survey questions about walking behavior. METHODS A 2005 California Health Interview Survey (CHIS) subsample (n = 6332) reported the number of days or times they walked for leisure or ...

Setup operations are significant in some production environments. It is mandatory that their production plans consider some features, as setup state conservation across periods through setup carryover and crossover. The modelling of setup crossover allows more flexible decisions and is essential for problems with long setup times. This paper proposes two models for the capacitated lot-sizing pr...

The present paper, titled “optimizing the time of preparation, taking into account the timing of   repair and maintenance using non-linear modeling”, has been implemented with the aim of designing and presenting a mathematical model to get the best sequence of operations leading to minimum the total time of production. The main research question is related to the reduction of time and productio...

This paper addresses an unrelated multi-machine scheduling problem with sequence-dependent setup time, release date and processing set restriction to minimize the sum of weighted earliness/tardiness penalties and the sum of completion times, which is known to be NP-hard. A Mixed Integer Programming (MIP) model is proposed to formulate the considered multi-criteria problem. Also, to solve the mo...

Different manufacturing enterprises use regularly scheduling algorithms in order to help meeting demands over time and reducing operational costs. Nowadays, for a better useofresources and manufacturingin accordance withcustomer needs and given the level ofcompetitionbetweencompanies, employing asuitablescheduling programhasa double importance. Conventional productionmethods are constantly subs...

This paper addresses the two-machine flowshop scheduling problemwith separate setup times to minimize makespan or total completion time (TCT). Setup times are relaxed to be random variables rather than deterministic as commonly used in the OR literature. Moreover, distribution-free setup times are used where only the lower and upper bounds are given. Global and local dominance relations are dev...