REORDER-POINT MODELS WITH DISCRETE PROBABILITY DISTRIBUTIONS

This paper is concerned with the determination of reorder points and safety-stock levels for situations where both the demand and lead-time distributions are discrete and independent. Formulas are developed for computing exact probabilities for the lead-time demand distribution on the basis of empirical distributions. Practitioners can use the model to obtain exact probabilities for situations where the computational burden is justified, while academicians can use the model to evaluate heuristic approaches to the reorder-point problem.     

Automatically Detected Nonverbal Behavior Predicts Creativity in Collaborating Dyads

In the current study we administered a creative task in which two people collaboratively generated novel strategies to conserve resources. During this task, the nonverbal behavior of 104 participants in 52 pairs was tracked and recorded using the Kinect computer vision algorithm. We created a measure of synchrony by correlating movements between the two dyad members, and showed that synchrony occurred—that is, correlations decreased when we increased delay between the recorded movements of pair members. We also demonstrated a link between nonverbal synchrony and creativity, as operationalized by the number of new, valid ideas produced. Linear correlations demonstrated a significant relationship between synchrony and creativity. Finally, models using synchrony scores as input predicted whether dyads were high or low in creativity with a success rate as high as 86.7 % in the more exclusive subsets. We discuss implications for methodological approaches to measuring nonverbal behavior and synchrony, and suggest practical applications which can leverage the current findings.     

Prevention of osteoporosis: one step forward, two steps back

For many years, hormone replacement therapy (HRT) was the mainstay for osteoporosis prevention in postmenopausal women until a large randomized clinical trial raised serious safety concerns. This resulted in a big drop in HRT use and its demotion by regulatory authorities to second-line treatment. Many clinicians now feel that HRT is not safe to use, and recommend various alternatives for the treatment of osteoporosis. But how effective are these alternative therapies, are they any safer than HRT, and how do their costs compare? This review questions the validity of the safety concerns about HRT, and highlights the safety concerns about alternative therapies. It concludes that HRT is as safe as the other treatment options, and its efficacy and low cost demand that it be restored as a first-line treatment for the prevention of postmenopausal osteoporosis. Other therapies are available for use in osteoporosis, and the bisphosphonates are particularly effective for the treatment of the established disease. However, they must be used selectively and with caution, and are best restricted to those patients who are elderly or have severe disease. New treatments are emerging, but again caution must be taken until any long-term adverse effects have been identified.     

The relationship of self-reported sex-role characteristics and attitudes toward homosexuality

The present study investigated the relationship between self-reported sex-role characteristics and attitudes toward homosexuality using the Bem Sex Role Inventory, the Personal Attributes Questionnaire and the Attitudes toward Homosexuality Scale. Relationships occur for both males and females who are exhibiting greater amounts of cross-sex traits. Females with more instrumental characteristics were more accepting while males with more expressive characteristics were more rejecting. These findings are discussed in relation to those of Weinberger and Millham (1979) who also investigated this relationship, as well as to research investigating the relationship between attitudes toward homosexuality and attitudes toward sex roles and feminism.     

Transforming Retirement: New Definitions of Life After Work

This quantitative research study uses survey data of women born between 1946 and 1951 in Australia. It follows earlier work that identified the importance of transitions from work for women of the baby boomer generation. We provide important insights into the lives of women who have partially or fully retired and the changing nature of women's work and retirement. For many women, retirement is characterized by newfound freedoms, opportunities, career change, and evolving identities, yet others view retirement as a continuation of previous occupational and gendered roles and commitments. This study has important implications for retirement policies for women.     

The effects of managerial decision making behaviour and order book size on workload control system implementation in Make-To-Order companies

Insufficient attention has been paid to behavioural influences on the implementation of the ‘Workload Control’ (WLC) concept – a Production Planning and Control (PPC) approach for small and medium sized Make-To-Order companies – and there is an implicit assumption that managers are rationalistic in their decision-making. This paper analyses the effects of both managerial decision-making behaviour and the size of a company’s order book, affecting the number of decisions that have to be made, on two case study implementations of a WLC system. The Recognition-Primed Decision (RPD) model from the Naturalistic Decision-Making literature is used to unpack the first case where implementation failed. This highlighted a misalignment between how the company’s owner-manager initially made operational decisions and how a rationalistic WLC system functions. But the company is studied over six years, allowing us to show how the owner-manager was forced to transition from the RPD model to a more rationalistic approach to PPC as the size of the order book increased. A second case study is then briefly presented in which WLC system implementation was successful; the RPD model was not strongly evident and the size of the order book was greater to begin with. The paper helps to understand the decision-making behaviour of managers in small companies and how it may conflict or be misaligned with the rationalistic assumptions underpinning the WLC concept. This provides a possible explanation for why few successful implementations of the concept have been presented in literature.     

Simple subcontracting rules for make-to-order shops with limited subcontractor capacity: an assessment by simulation

Companies that produce a high variety of customised products often suffer from large fluctuations in demand. Subcontracting can be an important means of overcoming resulting capacity shortages during high demand periods. A set of effective subcontracting rules, for determining which jobs to subcontract and which to produce internally, has recently been presented in the literature for this type of company. But evaluations of these rules have assumed subcontractor capacity is infinite. This study examines the impact of limited subcontractor capacity on the performance of the three best-performing subcontracting rules for make-to-order companies using a simulation model of an assembly job shop. Limiting subcontractor capacity inhibits the ability of a subcontracting rule to protect the internal shop from surges in demand, which negatively affects performance. However, significant performance differences between the rules evaluated are maintained, which underlines the importance of choosing the right subcontracting rule. Further analysis reveals that a limit on the work that can be subcontracted leads to less work being subcontracted more often, which requires adequate response by management. Meanwhile, the assumption of infinite capacity results in sporadically subcontracting a large amount of work. The results have important implications for future research and practice.     

Turnaround: from breakdown to breakthrough with Open Space Technology

This interpretive case study sought to fully understand and describe the turnaround experience from an organizational breakdown to breakthrough with the use of Open Space Technology. The turnaround occurred in a Roman Catholic parish. Participant interviews were used to collect the data. These qualitative portrayals provided insights and implications around the effectiveness and impact of Open Space. Four important themes emerged: the experience of breakdown, the deep longing for a breakthrough, the transformation of crisis into a turnaround and the effectiveness of Open Space Technology. This case study provides perspectives on how to effect transformation for an organization in crisis with the least effort and maximum impact within a short time span. It contains insights and implications for leaders and consultants to do the same.     

Workload Control and Order Release: A Lean Solution for Make‐to‐Order Companies

Protecting throughput from variance is the key to achieving lean. Workload control (WLC) accomplishes this in complex make‐to‐order job shops by controlling lead times, capacity, and work‐in‐process (WIP). However, the concept has been dismissed by many authors who believe its order release mechanism reduces the effectiveness of shop floor dispatching and increases work center idleness, thereby also increasing job tardiness results. We show that these problems have been overcome. A WLC order release method known as “LUMS OR” (Lancaster University Management School order release) combines continuous with periodic release, allowing the release of work to be triggered between periodic releases if a work center is starving. This paper refines the method based on the literature (creating “LUMS COR” [Lancaster University Management School corrected order release]) before comparing its performance against the best‐performing purely periodic and continuous release rules across a range of flow directions, from the pure job shop to the general flow shop. Results demonstrate that LUMS COR and the continuous WLC release methods consistently outperform purely periodic release and Constant WIP. LUMS COR is considered the best solution in practice due to its excellent performance and ease of implementation. Findings have significant implications for research and practice: throughput times and job tardiness results can be improved simultaneously and order release and dispatching rules can complement each other. Thus, WLC represents an effective means of implementing lean principles in a make‐to‐order context.     

Change in Covert Social Movement Networks: The ‘Inner Circle’ of the Provisional Irish Republican Army

In this paper, we contribute to both the growing body of literature on social movement networks and the growing body of literature on change in networks by exploring patterns and mechanisms of change within the network of the ‘inner circle’ of the Provisional Irish Republican Army. Specifically, we focus upon the period between 1969 (when it formed) and 1988 (the last point for which we have been able to gather good data). Our primary aims are substantive. We want to know how this network changed over time. In addition, however, our analysis identifies changes which other analysts might look for in their networks and offers methodological suggestions for those who, like us, find that their networks do not meet the assumptions of mainstream approaches to modelling network dynamics. There is a further dimension to the paper, however. We are studying a covert social movement network. This is a special type of movement network whose organisation and dynamics are predicted to vary from other movement networks. Some have suggested that they are inclined to be relatively static because the need for trust within them is so great and the risk to whatever they hold secret so considerable when new ties are formed that their members tend only to recruit within the pool of their pre-existing ties and actively seek to minimise recruitment and the formation of new ties. One of the aims of our paper was to determine whether and to what extent this is so.