We consider a general class of multiprocessor shop scheduling problems, preemptive or nonpreemptive, with precedence constraints between operations, with job or operation release dates, and with a class of objective functions including weighted sums of job, operations and stage completion times. We present a general approximation method combining a linear programming relaxation in the operation...

An interesting research area is to solve scheduling problems using network flow models and algorithms. Most of the existing papers in this research area deal with scheduling problems with parallel machines (identical and / or uniform machines). This paper considers the specialized case and develops network flow models and algorithms to solve open shop and flow and job shop problems.

3GPP work on the Evolution of the 3G Mobile System started with the RAN Evolution Work Shop, 2 3 November 2004 in Toronto, Canada. The Work Shop was open to all interested organizations, members and non members of 3GPP. Operators, manufacturers and research institutes presented more than 40 contributions with views and proposals on the evolution of the Universal Terrestrial Radio Access Network...

In this research, Lagrangian relaxation algorithms are proposed for Hybrid Flow-Shop (HFS) scheduling problems. Conventional HFS consists of a series of production stages, each of which has several identical parallel machines and no buffer spaces are considered. Jobs are processed through all stages in the same direction. In the previous researches, they are assumed that the capacity of buffer ...

We present a comprehensive complexity analysis of classical shop scheduling problems subject to various combinations of constraints imposed on the processing times of operations, the maximum number of operations per job, the upper bound on schedule length, and the problem type (taking values “open shop”, “job shop”, “mixed shop”). It is shown that in the infinite class of such problems there ex...

Preemptive open shop scheduling can be viewed as an edge coloring problem in a bipartite multigraph. In some applications, restrictions of colors (in particular preassignments) are made for some edges. We give characterizations of graphs where some special preassignments can be embedded in a minimum coloring (number of colors = maximum degree). The case of restricted colorings of trees is shown...

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...

Ideal schedules minimize both maximum completion time and total completion time of jobs. This paper presents polynomial-time algorithms finding ideal nonpreemptive and preemptive two-machine schedules of jobs with arbitrary release dates and precedence constraints and unit-execution-time operations on identical parallel machines, in a flow shop and an open shop. Heretofore, the complexity statu...

Open Shop is a classical scheduling problem: given a set J of jobs and a setM of machines, find a minimum-makespan schedule to process each job Ji ∈ J on each machine Mq ∈ M for a given amount piq of time such that each machine processes only one job at a time and each job is processed by only one machine at a time. In Routing Open Shop, the jobs are located in the vertices of an edge-weighted ...