ORGANIZATIONAL SEGMENTATION AND LABOR TRANSFER POLICIES IN LABOR AND MACHINE LIMITED PRODUCTION SYSTEMS

This paper describes a simulation study to examine the effects of different organizational structures on the performance of a dual-constraint job shop production system. A hypothetical shop in which machines and workers are constraining resources is the setting of the study. The shop consists of divisions comprised of work centers which contain machines to which workers are assigned. There are fewer workers than machines. Variations in organizational structure are achieved by segmenting a fixed number of work centers equally into varying numbers of divisions. Mean flow-time, flow-time variance, and worker transfers between divisions and work centers are used as performance measures. Changes in organizational segmentation are shown to affect the performance of the production system and the effects are dependent on the extent to which workers can be transferred between the divisions of the system.     

REPETITIVE LOTS: FLOW-TIME REDUCTIONS THROUGH SEQUENCING AND DYNAMIC BATCH SIZING

This paper presents a new integrative concept for job sequencing, dispatching, and lot sizing. The interrelation between these procedures and their impact on flow-time performance is examined in a capacitated production environment. Generally, lot-sizing decisions are made without regard to shop conditions and do not consider their impact on job sequencing procedures. The repetitive lots (RL) concept (developed and tested in this paper) attempts to integrate these decision processes. RL uses a number of features which have not been considered jointly in either the lot-sizing or job-dispatching/sequencing literature. These include operation batch sizes which vary by operation, transfer of work within the shop in quantities less than operation batch size, and the use of overlapped operations. A simulation model is used to analyze flow-time characteristics in a hypothetical production system. Traditional measures of flow-time performance are compared to a set of nontraditional measures which capture the interaction between lot sizing and the sequencing procedure used.     

Heterogeneous dispatching rules in job and flow shops

This paper reports the results of a study of the use of heterogeneous dispatching rules for the scheduling of work in a job shop. The methodology employed included discrete event simulation, using rule combinations determined by prior genetic algorithm searches and generalization using neural networks. Eight dispatching rules were considered, including first in first out (FIFO), earliest due date ( EDD), shortest processing time (SPT), slack/ number of operations (SLK), critical ratio (CR), modified due date (MDD), modified operation due date (MOD), and apparent tardiness cost (ATC). A three-machine job shop was studied, in which three work organizations were employed, pure flow (fixed sequence), pure job shop ( random sequence), and a hybrid shop where flow is random but with unequal probabilities. Three levels of machine loading were used and average tardiness was used as the performance measure. In most cases, modified due date and apparent tardiness cost were the best rules. The application of the best rules effected the results primarily when applied to bottleneck machines or the first machine in a pure flow shop. Nearly any other rule was acceptable on non-botdeneck machines except FIFO and CR, which consistently perform poorly. No major advantage of mixing rules was found.     

THE IMPACT OF SIMPLE PRIORITY RULE COMBINATIONS ON DELIVERY SPEED AND DELIVERY RELIABILITY IN A HYBRID SHOP

This study examines the effects of using different priority rules at different stages of a multistage, flow-dominant shop. A simulation model is constructed of a manufacturing system comprised of three stages: gateway, intcrmcdiatc, and finishing. As is typical of a flow-dominant shop, the overall flow of the simulated system (gateway to intermediate to finishing) is consistent with a flow shop, but processing in the intermediate stage involves multiple work centers and resembles a job shop. Shop performance is observed when four well-known priority heuristics are applied in different combinations in the gateway, intermediate, and finishing stages of the process. Multiple performance measures addressing the strategic objectives of delivery speed and delivery reliability are recorded under two different shop load conditions. Results show that the measures of both delivery speed and delivery reliability are affected by the priority rule combinations, and that a tradeoff exists between average performance and consistency of performance. Certain priority rule combinations affect performance in predictable ways, allowing the user to assess tradeoffs between delivery speed and delivery reliability.     

Lot Splitting in Unbalanced Production Systems*

This research investigates the impact of lot splitting in unbalanced production systems, under a variety of experimental conditions. Scheduling policies specifically designed for use in the presence of a long-term bottleneck, a condition frequently encountered in practice, are developed and tested. Results indicate that when steps are taken at nonbottleneck work centers to capitalize on capacity imbalances through increasing the number of setups and, hence, the variety of products produced, shop effectiveness is improved. The results also indicate that scheduling policies that tend to increase the size of the average process batch retard the overlapping of operations, which is critical to the success of the lot-splitting methodology in reducing flow time. Finally, it is shown that increasing capacity at nonbottleneck work centers along with implementation of effectiveness-oriented scheduling polices leads to improved shop performance.     

Well-being and organizational performance: An organizational-level test of the happy-productive worker hypothesis

Abstract

It is often assumed that happy workers are also productive workers. Although this reasoning has frequently been supported at the individual level, it is still unclear what these findings imply for organizational performance. Controlling for relevant work characteristics, this study presents a large-scale organizational-level test of the happy-productive worker hypothesis, assuming that high individual well-being leads to high individual-level performance, which should translate into high organizational performance (such as high efficiency and productivity). Job-specific employee well-being was measured as job satisfaction and emotional exhaustion. Using data from 66 Dutch home care organizations, the relationships among aggregated levels of demands, control, support, emotional exhaustion and satisfaction on the one hand, and organizational performance on the other, were examined using regression analysis. The hypotheses were partly confirmed, especially high aggregated levels of emotional exhaustion were related to low organizational performance. Although these findings support the reasoning that happy organizations are indeed productive organizations, more theorizing and more longitudinal research on the associations between individual-level well-being and organizational performance is imperative to improve understanding of these relationships. The findings underline the importance of improving worker well-being: this is not only important for individual workers, but may also have positive consequences for organizations and their clients.     

An Evaluation of Flexible Workday Policies in Job Shops*

Job shops have long faced pressures for improvement in a challenging and volatile environment. Today's trends of global competition and shortening of product life cycles suggest that both the challenges and the intensity of market volatility will only increase. Consequently, the study of tactics for maximizing the flexibility and responsiveness of a job shop is important. Indeed, there is a significant body of literature that has produced guidelines on when and how to deploy tactics such as alternate routings for jobs and transfers of cross‐trained workers between machines. In this paper we consider a different tactic by adjusting the length of workdays. Hours in excess of a 40‐hour week are exchanged for compensatory time off at time and a half, and the total amount of accrued compensatory time is limited to no more than 160 hours in accordance with pending legislation. We propose several simple flexible workday policies that are based on an input/output control approach and investigate their performance in a simulated job shop. We find significant gains in performance over a fixed schedule of eight hours per day. Our results also provide insights into the selection of policy parameters.     

Applications and Implementation: AN EXPERIMENTAL COMPARISON OF CELLULAR (GROUP TECHNOLOGY) LAYOUT WITH PROCESS LAYOUT

This study compares different strategies for arranging machines in a facility. Computer simulation of two different machine shops was used to compare process layout (the arrangement of groups of machines where the machines within a group are interchangeable) to cellular layout designed using group technology concepts (the use of manufacturing cells where each cell contains different types of machines dedicated to the production of similar parts). Four layout strategies, including process layout, cellular layout, and two hybrid layouts, were compared in two machine-shop models. The shops that used cellular layouts had shorter setup times, lower machine utilization, and shorter distances traveled, on average. The shops with process layout, however, had better performance on queue-related statistics such as work-in-process inventory level and average flow time. This suggests that a well-organized traditional job shop may be able to achieve overall performance that at least is comparable to that of the same shop using cellular (group technology) layout.     

Shop Floor Control When Tacit Worker Knowledge is Important

We investigate a shop where the workers and supervisors have tacit knowledge of how to operate efficiently and where efficiency is important to providing capacity to meet demand. This tacit knowledge includes setup dependencies between products as well as which worker or machine is best suited for a particular product. We discuss a real‐world shop where this is the case. Management expects workers and supervisors to use their knowledge to schedule efficiently by monitoring their performance based on standards. The question that we explore is how management should control for due date performance in light of the discretion given to the workers and supervisors to sequence jobs on the basis of efficiency. We explore management control of due date performance through the use of order review and release (ORR) and management expediting. We find that although ORR is quite effective at reducing work‐in‐process (WIP) inventories, it may foster very late deliveries in a shop such as this. In fact, under such conditions, deftly executed expediting with no ORR at all can be far more effective at supporting all deliveries. Even improving ORR into a hybrid by actively updating path efficiencies (observed from supervisor/worker scheduling) did not support a change to this conclusion. Conversely, when conditions are created where tacit knowledge plays a reduced role or utilization is decreased, ORR delivers in a timely manner. The interaction between utilization, WIP levels, and worker knowledge all help dictate the appropriate control methodology.     

A comparative analysis of due date based job sequencing rules in a flow shop with multiple processors

The literature on job scheduling recognizes the importance of due date performance criteria such as mean tardiness and maximum tardiness. A number of studies test a large number of sequencing rules for these criteria in job shop and flow shop settings. The object of this present research is to examine the performance of some well-known priority rules in a flow shop with multiple processors. This study investigates the performance of ten priority rules in terms of mean and maximum tardiness. It examines the effects of problem characteristics, such as number of jobs, number of machines stages and number of parallel processors at each stage, and the performance of priority rules using regression analysis. The findings of the study suggest that the primary determinants of tardiness-based criteria are problem characteristics. In addition, both the regression analysis and the analysis of variance provide strong evidence of the strategy-effect. Finally, a detailed performance review of examined priority rules for various problem characteristics is presented.     

Remote control: measuring performance for value creation and governance of globally distributed knowledge work

This article examines the governance of globally distributed knowledge work. To measure performance in knowledge work, it is important to focus on what the knowledge workers do and hence view knowledge as something one does, namely the practices, instead of something one has. By following the practices of knowledge work, it was possible to evaluate the effect of measures related to organizational processes, and identify what was not well covered by the measurement tool. Strategic and long term needs such as learning and employee competence are better managed through projects. This article shows how work performance in international organizations needs two different measures: one tool for measuring short-term value creation linked to the organizational processes; and, one tool for measuring long-term value creation linked to the practices of service work made in projects. Global governance of distributed employees is therefore successfully managed through key performance measures and through understanding projects through their multiple contributions, at both an individual and an organizational level. Global long term governance needs are strategic for the entire firm. The paper rests on an in-depth empirical case study of an international professional service firm.     

Optimal and Heuristic Models for Lot Splitting in a Flow Shop

This paper investigates optimal lot-splitting policies in a multiprocess flow shop environment with the objective of minimizing either mean flow time or makespan. Using a quadratic programming approach to the mean flow time problem, we determine the optimal way of splitting a job into smaller sublots under various setup times to run time ratios, number of machines in the flow shop, and number of allowed sublots. Our results come from a deterministic flow shop environment, but also provide insights into the repetitive lots scheme using equal lot splits for job shop scheduling in a stochastic environment. We indicate those conditions in which managers should implement the repetitive lots scheme and where other lot-splitting schemes should work better.     

How Does Performance Management Affect Workers? Beyond Human Resource Management and Its Critique

While performance management (PM) is pervasive across contemporary workplaces, extant research into how performance management affects workers is often indirect or scattered across disciplinary silos. This paper reviews and synthesizes this research, identifies key gaps and explores ‘recognition theory’ as a nascent framework that can further develop this important body of knowledge. The paper develops in three main stages. The first stage reviews ‘mainstream’ human resource management (HRM) research. While this research analyses workers’ reactions to performance management in some depth, its focus on serving organizational goals marginalizes extra‐organizational impacts. The second stage reviews more critical HRM research, which interprets performance management as a disciplinary, coercive or inequitable management device. While this literature adds an important focus on organizational power, there is scope to analyse further how PM affects workers’ well‐being. To develop this strand of PM research, the third stage turns to the emerging field of recognition theory independently developed by Axel Honneth and Christophe Dejours. The authors focus especially on recognition theory's exploration of how (in)adequate acknowledgement of workers’ contributions can significantly affect their well‐being at the level of self‐conception. Although recognition theory is inherently critical, the paper argues that it can advance both mainstream and critical performance management research, and also inform broader inquiry into recognition and identity at work.     

Multi-objective permutation flow shop scheduling problem: Literature review,classification and current trends

The flow shop scheduling problem is finding a sequence given n jobs with same order at m machines according to certain performance measure(s). The job can be processed on at most one machine; meanwhile one machine can process at most one job. The most common objective for this problem is makespan. However, many real-world scheduling problems are multi-objective by nature. Over the years there have been several approaches used to deal with the multi-objective flow shop scheduling problems (MOFSP). Hence, in this study, we provide a brief literature review of the contributions to MOFSP and identify areas of opportunity for future research.     

Work–family conflict and crossover in volunteer emergency service workers

Abstract

A growing literature indicates that organizational and work demands place pressure on the partners and families of volunteer workers as it does on paid workers. This study evaluated a conceptual model integrating work–family conflict and stress crossover theoretical frameworks, to investigate the mechanisms by which emergency service volunteer work, specifically, predicts outcomes for the partners of volunteers. Matched data from 102 couples in which one partner was an Australian emergency services volunteer – firefighter, ambulance officer or emergency rescue volunteer – were analysed using structural equation modelling analyses. Findings suggested that one mechanism by which inter-role conflict related to partner adjustment was through elevated withdrawn marital behaviour and decreased intimacy reported by the couple, which indirectly affected partners’ distress. This finding regarding withdrawn behaviour appears to be novel and may also be applicable to paid workers. Alternative mechanisms involving role overload and angry marital behaviour were not supported. These findings extend limited research which has adapted organizational theory to understand processes affecting volunteer workers, and advance conceptual accounts of the mechanisms through which the partners and families of workers are impacted by inter-role conflict.     

Dynamic scheduling of manufacturing job shops using extreme value theory

Most job shop scheduling approaches reported in the literature assume that the scheduling problem is static (i.e. job arrivals and the breakdowns of machines are neglected) and in addition, these scheduling approaches may not address multiple criteria scheduling or accommodate alternate resources to process a job operation. In this paper, a scheduling method based on extreme value theory (SEVAT) is developed and addresses all the shortcomings mentioned above. The SEVAT approach creates a statistical profile of schedules through random sampling, and predicts the quality or 'potential' of a feasible schedule. A dynamic scheduling problem was designed to reflect a real job shop scheduling environment closely. Two performance measures, viz. mean job tardiness and mean job cost, were used to demonstrate multiple criteria scheduling. Three factors were identified, and varied between two levels each, thereby spanning a varied job shop environment. The results of this extensive simulation study show that the SEVAT scheduling approach produces a better performance compared to several common dispatching rules.     

An asymptotically optimal algorithm for large-scale mixed job shop scheduling to minimize the makespan

This paper considers the large-scale mixed job shop scheduling problem with general number of jobs on each route. The problem includes ordinary machines, batch machines (with bounded or unbounded capacity), parallel machines, and machines with breakdowns. The objective is to find a schedule to minimize the makespan. For the problem, we define a virtual problem and a corresponding virtual schedule, based on which our algorithm TVSA is proposed. The performance analysis of the algorithm shows the gap between the obtained solution and the optimal solution is O(1), which indicates the algorithm is asymptotically optimal.     

Alternative uses of temporary work and new forms of work organisation

The purpose of this study is to investigate the relationship between the use of temporary workers and the adoption of new forms of work organisation (NFWO) in production. This study aims to understand to what extent these two forms of human resources flexibility are synergic or mutually exclusive. In order to answer this main goal, we discuss different levels of temporary workers adoption in relation to different levels of use of NFWO, the level of integration of temporary workers within the overall production organisation and the joint and synergistic use of NFWO and temporary work. Evidence drawn from seven case studies in manufacturing plants in northern Italy is provided. Results highlight that, according to the characteristics of the production process, temporary workers and NFWO are not mutually exclusive, that temporary workers can be integrated with other workers in the shop floor, and that NFWO can also be adopted for temporary workers. In addition, NFWO has been proven to be a key enabler to integrate temporary workers within the organisation, thus showing an important synergistic effect between the two human resource flexibility practices.     

Flow shop scheduling by transportation model

This paper describes the classical problem of scheduling n jobs on m machines in a flow shop. A schedule evaluation algorithm is presented, which for job-pairs, generates a schedule evaluation matrix. The matrix is the input data to a transportation problem, the solution of which gives near-optimal jobsequence and makespan. The performance of the algorithm is discussed.     

The Job Demands-Resources Model in emergency service volunteers: Examining the mediating roles of exhaustion,work engagement and organizational connectedness

Using a sample of 887 volunteer emergency service workers in South Australia, we conducted a study based on the JD-R framework to examine the roles of three mediators in the relationship between job characteristics and volunteer well-being. These were (i) exhaustion as a mediator in the relationships between job demands and both poor mental health and turnover intentions; and (ii) work engagement and organizational connectedness as mediators in the relationships of job resources (training and organizational support) with happiness and turnover intentions. Organizational connectedness, a relatively new construct, is a positive state of well-being that involves an emotional connection with other workers, with service recipients and with aspects of the task and the organization's values. Results indicated that all three mediators were important in explaining volunteer well-being. Specifically, job demands were positively related to exhaustion, which, in turn, was linked to ill-health and turnover intentions. Job resources were positively related to work engagement and organizational connectedness, which were, in turn, negatively related to turnover intentions. However, while organizational connectedness mediated the relationship between job resources and happiness, this was not the case for work engagement. The roles of these variables in future research in paid and voluntary work are discussed.