OBJECTIVES To describe the prevalence of musculoskeletal problems in the Canadian working population and to determine cross sectional associations between such problems and work factors, particularly job strain and physical demand variables. METHODS The Canadian 1994 national population health survey (NPHS) sampled 4230 working men and 4043 working women (ages 18-64) who answered an abbreviat...

BACKGROUND This paper is embedded in a randomised controlled trial (Alcohol and Employment) that investigated whether welfare-to-work schemes combined with alcohol treatment were more effective than welfare-to-work schemes alone for helping unemployed welfare recipients with alcohol problems get back to employment and reduce their alcohol problems. The implementation of Alcohol and Employment t...

Recent research has shown the existence of a “phase transition” for many combinatorial problems. In this paper we investigate the existence of a phase transition in the job shop scheduling problem. We apply standard estimates for the constrainedness of constraint satisfaction problems to job shop problems and describe empirical results identifying a phase transition at a constrainedness level o...

This paper describes a new approach for solving disjunctive temporal problems such as the open shop and job shop scheduling domains. Much previous research in systematic search approaches for these problems has focused on developing problem specific constraint propagators and ordering heuristics. Indeed, the common belief is that many of these problems are too difficult to solve without such do...

In this paper, we consider the scheduling problems with exponential learning effect. By the exponential learning effect, we mean that the processing time of a job is defined by an exponent function of the sum of the normal processing times of the already processed jobs. We consider the following objective functions: the makespan, the total completion time, the sum of the quadratic job completio...

BACKGROUND The workplace environment has a great influence on employees' health. Job dissatisfaction has been widely recognised as a workplace stressor that can influence employees' psychological and physical health statuses. However, job satisfaction is a multi-dimensional concept, and it is necessary to investigate its different facets and their unique consequences. Therefore, the aim of this...

Recent research highlights the importance of both job resources and personal resources in the job demands-resources model. However, the results of previous studies on how these resources are related to each other and how they operate in relation to the health-impairment process of the job demands-resources model are ambiguous. Thus, the authors tested an alternative model, considering job and p...

health and wellbeing has always been an important concept of relevance for concerned health specialists and workers. the present study envisages to look at the nature of occupational stressors and mental health problems in a group of hospital employees at the zahedan university of medical sciences. the study was carried out on 130 employees chosen from various hospitals in zahedan. results reve...

In this paper, scheduling problems in Flexible Manufacturing Cells (FMC) are studied. The scheduling objective is to minimize the makespan. We used a genetic algorithm (GA) for solving the optimization scheduling problem. We have developed one FMC with industrial characteristics with the objective of studying scheduling problems in these types of manufacturing systems (single machine scheduling...

We consider several combinatorial optimization problems which combine the classic shop scheduling problems, namely open shop scheduling or job shop scheduling, and the shortest path problem. The objective of the obtained problem is to select a subset of jobs that forms a feasible solution of the shortest path problem, and to execute the selected jobs on the open (or job) shop machines to minimi...