A branch and bound and simulated annealing approach for job shop scheduling

This paper presents two approaches to the solution of the job shop scheduling problem, namely the branch and bound, and simulated annealing approach. The objective is to schedule the jobs on the machines so that the total completion time is minimized. In the branch and bound approach, the job shop scheduling problem is represented by a disjunctive graph, then the optimal schedule is obtained using the branch and bound algorithm while simulated annealing is a local search based algorithm which will slightly perturb the initial feasible solution to decrease the makespan

Survival and disinfection of SARS-Cov-2 in environment and contaminated surface

The detection of SARS-Cov-2 in the sewage and water resources has increased the awareness among the people about the possibility survival of SARS-Cov-2 in the environment and the potential to transmit into the human through food chain or water resources. Moreover, the surface contaminated by the virus need to be disinfected frequently by using an effective disinfectant, the current chapter discussed the efficiency of the most traditional treatment process of the sewage and wastewater, and their role in the elimination of the virus as well as the sterility assurance level concept. Moreover, the chemical disinfectant used currently and their temporary efficiency has been reviewed

Xerox Cuts Costs Without Layoffs Through Union-Management Collaboration

The case study that follows deals with Xerox Corporation, a multinational equipment manufacturing company that decided to work with its union to find ways to use employees\u27 skills and new technologies in addressing economic problems in its manufacturing division. The specific labor-management cooperation project described here began after the Xerox Corporation decided that to produce some of its products competitively, it would need to save over 53 million in production costs. At first, the only solution the company saw was closing down one department, laying off ISO employees, and subcontracting the manufacturing of component parts. But this did not happen. Instead, the company and union agreed to try the unorthodox route of collaboration to solve economic and production problems—without any layoffs. This collaborative effort came despite a companywide downsizing policy that resulted in extensive layoffs throughout Xerox

Dynamic algorithms for order acceptance and capacity planning within a multi-project environment.

Algorithms; Algorithm; Order; Order acceptance; Capacity planning; Planning; multi-project; International; Scheduling; Theory; Applications;

A hybrid shifting bottleneck-tabu search heuristic for the job shop total weighted tardiness problem

In this paper, we study the job shop scheduling problem with the objective of minimizing the total weighted tardiness. We propose a hybrid shifting bottleneck - tabu search (SB-TS) algorithm by replacing the reoptimization step in the shifting bottleneck (SB) algorithm by a tabu search (TS). In terms of the shifting bottleneck heuristic, the proposed tabu search optimizes the total weighted tardiness for partial schedules in which some machines are currently assumed to have infinite capacity. In the context of tabu search, the shifting bottleneck heuristic features a long-term memory which helps to diversify the local search. We exploit this synergy to develop a state-of-the-art algorithm for the job shop total weighted tardiness problem (JS-TWT). The computational effectiveness of the algorithm is demonstrated on standard benchmark instances from the literature