Just-in-time scheduling with controllable processing times on parallel machines

We study scheduling problems with controllable processing times on parallel machines. Our objectives are to maximize the weighted number of jobs that are completed exactly at their due date and to minimize the total resource allocation cost. We consider four different models for treating the two criteria. We prove that three of these problems are NP\mathcal{NP} -hard even on a single machine, but somewhat surprisingly, the problem of maximizing an integrated objective function can be solved in polynomial time even for the general case of a fixed number of unrelated parallel machines. For the three NP\mathcal{NP} -hard versions of the problem, with a fixed number of machines and a discrete resource type, we provide a pseudo-polynomial time optimization algorithm, which is converted to a fully polynomial time approximation scheme.     

The stressor–strain relationship in diary studies: A meta-analysis of the within and between levels

Daily diary studies use the same set of measures repeatedly for several days. Within the work stress domain, these studies are able to isolate the effects of daily exposure to stressors within people from the general level of stressors between people. This meta-analysis investigated both content-related and methodological aspects of workplace stressor–strain relationships in diary studies. Results from 55 unique samples (a combined sample size of 5409) indicated that the magnitude of the stressor–strain relationship was stronger at the between-person level than the within-person level. Further, when the stressor was measured prior to the strain (within the same day), the relationship was somewhat stronger than when stressor and strain were measured concurrently. This suggests that stressor–strain effects might take some time to fully manifest. Differences were also detected among types of strains: affective strains had stronger relationship with stressors than behavioural strains. There were also differences in the stressor–strain relationship depending on both the type of strain and the timing of their respective measurement (concurrent versus predictive), suggesting that certain strain responses require more time to manifest. Overall, this meta-analysis elucidates important considerations in the design and interpretation of diary studies on occupational stress.     

Illegitimate tasks are not created equal: Examining the effects of attributions on unreasonable and unnecessary tasks

ABSTRACT

Illegitimate tasks are tasks that violate norms for what the employee should do as part of the job, and have been found to harm employees’ well-being. The current research uses a mixed methods design to examine the role of attributions on the two types of illegitimate tasks: unreasonable and unnecessary tasks. A sample of 432 engineers described a specific illegitimate task that was assigned to them, the attributions they made and their response. They also completed a quantitative questionnaire. Results from both the qualitative (event level) and quantitative (person level) portions of our study portray differences in the attributions made to unreasonable and unnecessary tasks, as well as differential negative effects on employees’ emotions. In addition, hostile attribution bias was found to moderate the relationship between illegitimate tasks and negative emotions, particularly for unreasonable tasks. This supports the theoretical basis for illegitimate tasks because unreasonable tasks pose a potentially greater risk to the employee’s self-worth than unnecessary tasks that are more often assigned at random.     

Child involvement in treatment planning and assessment in Israel

What can facilitate at‐risk children's involvement in treatment planning and assessment? We examine this question by investigating the perceptions, attitudes, and characteristics of Israeli social workers. We examine whether their seniority, views on the importance of children's participation, and their attitudes toward parents are related to their report of at‐risk children's involvement in treatment planning and placement decisions. At‐risk children's involvement includes preparing them to appear before the committees that handle placement decisions for youth and the social workers' willingness to consider children's opinions. Eighty coordinators of these committees in social services departments in Israel participated. Our findings indicate that, based on the coordinators' answers, at‐risk children are more likely to be involved in treatment planning and assessment committees when the child protection officers prepare parents prior to participating in the committee meetings, and when the coordinators assigned the case are more senior. The influence of children's opinions on the decisions of the committees was predicted by the weight their parents' opinions carried and whether their parents received any relevant materials prior to the committee meetings. Our findings highlight the importance of involving parents in treatment planning and assessment committees' decision making.     

Intervention Research as Management Research in Practice: Learning from a Case in the Fashion Design Industry

Research in the field of management and organizational sciences has yielded a deeper understanding of many emerging business issues. However, the relevance of the contributions has been increasingly criticized, in both the academic and public spheres. We propose the intervention research approach – originally developed by the research group at Ecole des Mines de Paris – as a design science approach able to address both the relevance gap issue and the growing complexity of management practice. It is argued that increasing our understanding of management requires research that is more insightful, influential and immediately applicable. This in turn requires closer collaboration between management and researchers during the inquiry process, which is not always easy to achieve. An illustrative case study of an intervention research project focusing on creativity, conducted in Italy in collaboration with a fashion company, demonstrates how intervention research can be rigorous and relevant to practitioners, and how it can advance theoretical knowledge in management science.     

Organizational constraints: a meta-analysis of a major stressor

The stressor organizational constraints, reflecting aspects of the work environment that inhibit or interfere with an individual's performance of job tasks, is prevalent in the workplace. This meta-analysis summarizes findings concerning the relationships of organizational constraints with other variables. Using five search methods, we located 84 research reports that provided data from 119 independent samples that contained 33,998 employed individuals. Fitting a stressor–strain framework, constraints had significant relationships with behavioural (counterproductive work behaviour), physical (somatic symptoms), and psychological (e.g. emotions and job dissatisfaction) strains and with well-being variables. Relationships were also found with all other work environment variables, and most personal characteristics (demographics and personality) except for gender. Moreover, a series of regression and relative weights analyses based on meta-analytic correlations showed that constraints had a unique contribution to strain beyond other stressors. The current meta-analysis shows that many commonly studied variables are related to organizational constraints, and it should more often be the centre of empirical research and theoretical development.     

Evaluating SafeCare® in Israel: Benefits for the families

SafeCare® is a home‐based intervention programme targeting parents of children up to 5 years old and is designed to reduce and even prevent child abuse and neglect. Here, we present an evaluation of a pilot trial of SafeCare® in Israel, examining family's outcomes. We examined parents' behavioural changes resulting from the three main modules of SafeCare®: the Health, Safety, and Parent‐Child/Infant Interaction. We also studied the unplanned effects of SafeCare® by examining maternal depressive symptoms. Participants were 46 mothers with children identified as being at risk of neglect by the local Department of Social Services who completed the programme. The mothers filled out questionnaires at the beginning and at the end of their participation. After completing the programme, mothers' self‐reports showed changes in how they would treat a sick child, an increase in feelings of competency, and a decline in symptoms of depression. We thus conclude that SafeCare® helped the participating mothers, enhancing their feelings of competency and changing several of their behaviours.     

A bicriteria approach to scheduling a single machine with job rejection and positional penalties

Single machine scheduling problems have been extensively studied in the literature under the assumption that all jobs have to be processed. However, in many practical cases, one may wish to reject the processing of some jobs in the shop, which results in a rejection cost. A solution for a scheduling problem with rejection is given by partitioning the jobs into a set of accepted and a set of rejected jobs, and by scheduling the set of accepted jobs among the machines. The quality of a solution is measured by two criteria: a scheduling criterion, F1, which is dependent on the completion times of the accepted jobs, and the total rejection cost, F2. Problems of scheduling with rejection have been previously studied, but usually within a narrow framework—focusing on one scheduling criterion at a time. This paper provides a robust unified bicriteria analysis of a large set of single machine problems sharing a common property, namely, all problems can be represented by or reduced to a scheduling problem with a scheduling criterion which includes positional penalties. Among these problems are the minimization of the makespan, the sum of completion times, the sum and variation of completion times, and the total earliness plus tardiness costs where the due dates are assignable. Four different problem variations for dealing with the two criteria are studied. The variation of minimizing F1+F2 is shown to be solvable in polynomial time, while all other three variations are shown to be $\mathcal{NP}$ -hard. For those hard problems we provide a pseudo polynomial time algorithm. An FPTAS for obtaining an approximate efficient schedule is provided as well. In addition, we present some interesting special cases which are solvable in polynomial time.