Search results for "scheduling"
showing 10 items of 275 documents
Improving Of The Productivity And The Quality Of A Manufacturing Robotized Cell For Mig/Mag Welding
2007
During the last years, globalization and the necessity to reduce production costs have pushed industry to employ more and more manufacturing robotized cells. This trend has been assimilated by arc welding too. The use of robotic systems allows to increase the performance of productive systems by means of reduction in lead-time, reproducibility of processes and increase in quality. However, process automation needs pre-scheduling of manufacturing cell movements and also a setup of different welding parameters, such as power provided by the welding generator, arc length and robot speed, all of which allows to get a joint without defects. An online scheduling of robotic systems brings certainl…
Working hours and sleep duration in midlife as determinants of health-related quality of life among older businessmen
2017
Background long working hours and short sleep duration are associated with a range of adverse health consequences. However, the combined effect of these two exposures on health-related quality of life (HRQoL) has not been investigated. Methods we studied white men born between 1919 and 1934 in the Helsinki Businessmen Study (HBS, initial n = 3,490). Data on clinical variables, self-rated health (SRH), working hours and sleep duration in 1974, and RAND-36 (SF-36) HRQoL survey in the year 2000 were available for 1,527 men. Follow-up time was 26 years. By combining working hours and sleep duration, four categories were formed: (i) normal work (≤50 hours/week) and normal sleep (>47 hours/week);…
Validity and reliability of Resource Utilization Groups (RUG-III) in Finnish long-term care facilities
1999
Resource Utilization Groups, Version III (RUG-III) is a case-mix system developed in the USA for classification of long-term care residents. This paper examines the validity and reliability of an adapted 22-group version of RUG-III (RUG-III/22) for use in long-term care facilities in Finland. Finnish cost weights for RUG-III/22 groups are calculated and different methods for their computation are evaluated. The study sample (1,964 residents) was collected in 1995 - 96 from ten long-term care facilities in Finland. RUG-III/22 alone explained 38.2% of the variance of total patient-specific (nursing + auxiliary staff) per diem cost. Resource use within RUG groups was relatively homogeneous. O…
Consolidation of working hours and work-life balance in anaesthesiologists - A cross-sectional national survey.
2018
Currently, healthcare management fosters a maximization of performance despite a relative shortage of specialists. We evaluated anaesthesiologists' workload, physical health, emotional well-being, job satisfaction and working conditions under increased pressure from consolidated working hours. A nationwide cross-sectional survey was performed in Austrian anaesthesiologists (overall response rate 41.0%). Three hundred and ninety four anaesthesiologists (280 specialists, 114 anaesthesiology trainees) participated. Anaesthesiologists reported frequently working under time pressure (95%CI: 65.6-74.6), at high working speed (95%CI: 57.6-67.1), with delayed or cancelled breaks (95%CI: 54.5-64.1),…
Tabu search for a multi-objective routing problem
2006
Multi-objective optimization problems deal with the presence of different conflicting objectives. Given that it is not possible to obtain a single solution by optimizing all the objectives simultaneously, a common way to face these problems is to obtain a set of efficient solutions called the non-dominated frontier. In this paper, we address the problem of routing school buses with two objectives: minimize the number of buses, and minimize the longest time a student would have to stay in the bus. The trade-off in this problem is between service level, which is represented by the maximum route length, and operational cost, which is represented by the number of buses in the solution. We prese…
Scatter tabu search for multiobjective clustering problems
2011
We propose a hybrid heuristic procedure based on scatter search and tabu search for the problem of clustering objects to optimize multiple criteria. Our goal is to search for good approximations of the efficient frontier for this class of problems and provide a means for improving decision making in multiple application areas. Our procedure can be viewed as an extension of SSPMO (a scatter search application to nonlinear multiobjective optimization) to which we add new elements and strategies specially suited for combinatorial optimization problems. Clustering problems have been the subject of numerous studies; however, most of the work has focused on single-objective problems. Clustering u…
Constructing Good Solutions for the Spanish School Timetabling Problem
1996
In the school timetabling problem a set of lessons (combinations of classes, teachers, subjects and rooms) has to be scheduled within the school week. Considering classes, teachers and rooms as resources for the lessons, the problem may be viewed as the scheduling of a project subject to resource constraints. We have developed an algorithm with three phases. In Phase I an initial solution is built by using the scheme of parallel heuristic algorithm with priority rules, but imbedding at each period the construction of a maximum cardinality independent set on a resource graph. In Phase II a tabu search procedure starts from the solution of Phase I and obtains a feasible solution to the proble…
Tabu search algorithms for an industrial multi-product and multi-objective assembly line balancing problem, with reduction of the task dispersion
2002
This paper presents a real-world industrial application of the multi-product and multi-objective assembly line balancing problem, for a company involved in the production of four models of a white goods product. The problem solved is a GALBP-2, with 10 workstations and multiple objectives (to maximize the production rate in order to deal with an increase of the demand forecasted, to reach an equal cycle time of all the models and an equal workload of the different workstations, and finally, to minimize the dispersion of worker tasks on each one of the different models-the common tasks of the different models at the same workstation). The paper presents an integrated approach based on four h…
Heuristic solutions to the problem of routing school buses with multiple objectives
2002
In this paper we address the problem of routing school buses in a rural area. We approach this problem with a node routing model with multiple objectives that arise from conflicting viewpoints. From the point of view of cost, it is desirable to minimise the number of buses used to transport students from their homes to school and back. From the point of view of service, it is desirable to minimise the time that a given student spends en route. The current literature deals primarily with single-objective problems and the models with multiple objectives typically employ a weighted function to combine the objectives into a single one. We develop a solution procedure that considers each objecti…
Labour Scheduling at an Airport Refuelling Installation
1999
We have developed an automatic assignment procedure for labour scheduling at a continously operating airport refuelling installation. Different types of workers are subject to different conditions on the shifts they can do (morning, evening or night), shift lengths, days-off, holidays, terms of contract and working hours. The scheduling process is carried out on a weekly basis, but there are mid-term and long-term conditions and objectives which link each week with the preceding and following weeks. Our package uses firstly a tabu search algorithm to find the best schemes of shifts/days-off to be used to cover the requirements. Secondly, an assignment problem is solved to match the schemes …