Minimizing makespan for hybrid flowshops with batch, discrete processing machines and arbitrary job sizes

This research aims at a study of the hybrid flow shop problem which has parallel batch-processing machines in one stage and discrete-processing machines in other stages to process jobs of arbitrary sizes. The objective is to minimize the makespan for a set of jobs. The problem is denoted as: FF: batch1,sj:Cmax. The problem is formulated as a mixed-integer linear program. The commercial solver, AMPL/CPLEX, is used to solve problem instances to their optimality. Experimental results show that AMPL/CPLEX requires considerable time to find the optimal solution for even a small size problem, i.e., a 6-job instance requires 2 hours in average. A bottleneck-first-decomposition heuristic (BFD) is proposed in this study to overcome the computational (time) problem encountered while using the commercial solver. The proposed BFD heuristic is inspired by the shifting bottleneck heuristic. It decomposes the entire problem into three sub-problems, and schedules the sub-problems one by one. The proposed BFD heuristic consists of four major steps: formulating sub-problems, prioritizing sub-problems, solving sub-problems and re-scheduling. For solving the sub-problems, two heuristic algorithms are proposed; one for scheduling a hybrid flow shop with discrete processing machines, and the other for scheduling parallel batching machines (single stage). Both consider job arrival and delivery times. An experiment design is conducted to evaluate the effectiveness of the proposed BFD, which is further evaluated against a set of common heuristics including a randomized greedy heuristic and five dispatching rules. The results show that the proposed BFD heuristic outperforms all these algorithms. To evaluate the quality of the heuristic solution, a procedure is developed to calculate a lower bound of makespan for the problem under study. The lower bound obtained is tighter than other bounds developed for related problems in literature. A meta-search approach based on the Genetic Algorithm concept is developed to evaluate the significance of further improving the solution obtained from the proposed BFD heuristic. The experiment indicates that it reduces the makespan by 1.93 % in average within a negligible time when problem size is less than 50 jobs.

Dynamic job quoting system for printed circuit board fabrication

This research deals with the development of a dynamic job quotation system for printed circuit board (PCB) fabrication, which can estimate the price and completion time of a job based on customer preference and current capacity of the shop floor. The primary purpose of building a dynamic quotation system is to maximize the company's profit by quoting optimum lead-time and competitive price for the day-to-day orders received from different customers and original equipment manufacturers. The system was developed using MS-Access relational database. Evaluating the output of the system it was observed that the dynamic system provided more reliable estimation of the lead-time needed for fabricating new jobs. The overall price quoted by the system was competitive with higher profit margin when compared to traditional static systems. This system would therefore provide a vital link between the job quoting and scheduling system of the firm enabling better utilization of the available resources.

Employability and job status as moderators of the effects of job insecurity on work outcomes

Despite greater use of temporary employment contracts, little is known about how employees react to job length uncertainty. Individual careers within the safety of one or two primary organisations are no longer the norm. This study investigates the effects of job insecurity and employment status (temporary/permanent) on work outcomes. Three hundred and ninety-one employees (122 temporary and 269 permanent) in low to medium level non-academic positions from two Australian universities completed a survey. The results show that a belief that comparable employment is easily available did not alleviate the negative effects of job insecurity. Work attitudes for temporaries and permanents though were differentially influenced by employee perceptions of their own employability.

Full-time is a given here : part-time versus full-time job quality

This study explores full-time workers' understanding of and assumptions about part-time work against six job quality components identified in recent literature. Forty interviews were conducted with employees in a public sector agency in Australia, a study context where part-time work is ostensibly 'good quality' and is typically long term, voluntary, involving secure contracts (i.e. permanent rather than casual) and having predictable hours distributed evenly over the week and year. Despite strong collective bargaining arrangements as well as substantial legal and industrial obligations, the findings revealed some serious concerns for part-time job quality. These concerns included reduced responsibilities and lesser access to high status roles and projects, a lack of access to promotion opportunities, increased work intensity and poor workplace support. The highly gendered, part-time labour market also means that it is women who disproportionately experience this disadvantage. To foster equity, greater attention needs to focus on monitoring and enhancing job quality, regardless of hours worked.

'Getting a job' : Aborignal Women's issues and experiences in the health sector

Indigenous participation in employment has long been seen as an indicator of Indigenous economic participation in Australia. Researchers have linked participation in employment to improved health outcomes, increased education levels and greater self-esteem. There has been a dramatic increase in the number of Indigenous workforce policies and employment strategies as employers and industries attempt to employ more Aboriginal and Torres Strait Islander people. Coupled with this has been a push to employ more Indigenous people in specific sectors to address the multiple layers of disadvantage experienced by Indigenous people, for example, the health sector. This paper draws on interview discussions with Aboriginal women in Rockhampton, Central Queensland, along with findings from the research of others to offer a greater understanding of the mixed benefits of increased Indigenous employment. What is demonstrated is that the nature of Indigenous employment is complex and not as simple as ‘just getting a job’.

Curvilinear relationships between the job demands-resources (JD-R) model, and work engagement : a police service case study

The current study aims to investigate the non-linear relationship between the JD-R model and work engagement. Previous research has identified linear relationships between these constructs; however there are strong theoretical arguments for testing curvilinear relationships (e.g., Warr, 1987). Data were collected via a self-report online survey from officers of one Australian police service (N = 2,626). Results demonstrated a curvilinear relationship between job demands and job resources and engagement. Gender (as a control variable) was also found to be a significant predictor of work engagement. The results indicated that male police officers experienced significantly higher job demands and colleague support than female officers. However, female police officers reported significantly higher levels of work engagement than male officers. This study emphasises the need to test curvilinear relationships, as well as simple linear associations, when measuring psychological health.

Does occupational stress really matter? A study of psychological climate and stress on job satisfaction in Thailand

This study explored the prediction of psychological climate and stresses on job satisfaction in non U.S. setting. A total of 450 surveys were sent to 11 organisations in Thailand and employees were asked to fill out the survey. The first hypothesis that positive psychological climate dimensions predicted lower level of stresses among Thai employees was partially accepted. Further regression analysis tested second hypothesis that positive psychological climate dimensions and low level of stresses predict job satisfaction among Thai employees. Contrary to expectation, only stress variables predicted job satisfaction. Thai culture influence was discussed.