Yuri N. Sotskov

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One of the largest environmental polluters in Chapaevsk (Samara Region, Russia) is the Middle Volga chemical plant. From 1967 to 1987, it produced hexachlorocyclohexane (lindane) and its derivatives. Currently, it produces crop protection chemicals (liquid chlorine acids, methyl chloroform, vinyl chloride, and some other chemicals). Dioxins were detected in(More)
This paper deals with the problem of scheduling n jobs on m machines in order to minimize the maximum completion time or mean flow time of jobs. We extend the results obtained in Sotskov (1989, 1990, 1991) on the complexity of shop-scheduling problems with n = 3. The main result of this paper is an NP-hardness proof for scheduling 3 jobs on 3 machines,(More)
This paper surveys the recent results in stability analysis for discrete optimization problems, such as a traveling salesman problem, an assignment problem, a shortest path problem, a Steiner problem, a scheduling problem and so on. The terms “stability”, “sensitivity” or “postoptimal analysis” are generally used for the phase of an algorithm at which a(More)
We consider an uncertain single-machine scheduling problem, in which the processing time of a job can take any real value on a given closed interval. The criterion is to minimize the total weighted flow time of the n jobs, where there is a weight associated with a job. We calculate a number of minimal dominant sets of the job permutations (a minimal(More)
We consider a single-machine scheduling problem with each job having an uncertain processing time which can take any real value within each corresponding closed interval before completing the job. The scheduling objective is to minimize the total weighted flow time of all n jobs, where there is a weight associated with each job. We establish the necessary(More)
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(More)
The two-machine permutation flowshop scheduling problem to minimize makespan or total completion time criterion is addressed where setup times are considered to be separate from processing times. Setup times are relaxed to be random variables as opposed to the common assumption in the literature that setup times are exactly known (deterministic) in advance.(More)
The shop-scheduling problem with two jobs andm machines is considered under the condition that the machine order is fixed in advance for the first job and nonfixed for the second job. The problems of makespan and mean flow time minimization are proved to be NP-hard if operation preemption is forbidden. In the case of preemption allowance for any given(More)