Efficient flow control of jobs in assembly lines

This paper addresses the issues of efficient flow control techniques for jobs in assembly lines. We propose a queuing theoretic approach for efficient flow control of jobs. An assembly line performance measure (ALPM) is used as the measure of performance for each assembly line and is denned as the ratio of throughput to total average delay of an assembly line (AL). A performance product criterion (PPC) is used as the performance measure of a cluster of ALs. It is shown that the performance product criterion has a unique maximum in throughput space. Two algorithms are presented to find the maximum of the performance product criterion in two different cases of assembly line environment. In the first algorithm, we attempt to maximize the performance product criterion with respect to the throughputs of the assembly lines in the entire throughput space. The second algorithm maximizes the performance product criterion when the sum of the throughputs of the ALs is fixed. Numerical examples are given as illustrations of the algorithms.     

An investigation of output flow control,bottleneck flow control and dynamic flow control mechanisms in various simple lines scenarios

Flow control mechanisms have been a topic of academic research for several years. With the growth of business-wide information systems such as enterprise resource planning and supply chain, better planning, scheduling and control of the business transformation process is required in order to achieve increased throughput, reduced inventories, shorter lead times and reduced tardiness. This research compares two new approaches to flow control, output flow control and bottleneck flow control to a real-time flow control system, dynamic flow control. Both output and bottleneck flow control mechanisms are much simpler to implement and manage than dynamic flow control in that they do not require continual feedback and rescheduling. Line characteristics, such as location of breakdowns with respect to the bottleneck, the location of the bottleneck when breakdowns occur, and the impact of variability of processing times on the performance measures (output, WIP level, lateness, and number of tardy jobs) for these three flow control mechanisms are compared. Both output and bottleneck flow control mechanisms perform favourably (particularly bottleneck) under different scenarios and warrant further study across a wider range of scenarios (mixed models, job shops, etc.).     

Work-self balance: A longitudinal study on the effects of job demands and resources on personal functioning in Japanese working parents

Abstract

In work-family research the effects on the individual, or the “self”, in terms of personal interests independent of the work and family domains, have been largely neglected. This longitudinal study on 471 Japanese employees with young children investigated how job demands and job resources may have an impact on well-being by facilitating or hindering personal functioning. It was hypothesized that workload would have an unfavourable impact on work-to-self conflict, while supervisor support would have a favourable impact on work-to-self facilitation. In addition, we hypothesized that work–self conflict would diminish well-being (psychological distress and happiness), while work–self facilitation would enhance well-being over time. Structural equation modelling analyses using a full panel design showed that work overload was positively related to work–self conflict over time, whereas supervisor support was positively related to work–self facilitation. Furthermore, work–self conflict predicted psychological distress and happiness at T2, one year later, after controlling for T1 levels. These findings suggest that the demands and resources encountered at work can spill over to the home domain and have an impact on personal functioning and context-free well-being. Further research is needed to determine the importance of work-self constructs in relation to work-family constructs.     

The effects of fitness training on the physiological stress response

The favourable psychological and physiological profile found in fit sportsmen does not necessarily follow from their exercise behaviour. Alternatively it may depend on endowment and/or self-selection. In that case, participation in regular exercise may not always result in a reduction of susceptibility to stress. The present article reviews several well-controlled laboratory studies that have directly examined the effect of fitness training programmes on the physiological responses to a set of standardized stressors. It was generally expected that fitness training would enhance psychological stress resistance and thus mitigate the physiological response to stress. The results of most studies belie these expectations. Intensive training programmes of up to 8 months do not change stress reactivity, even if initially low fit and high stress-reactive subjects are used. The failure to find a training effect on the intensity of the stress reactions in laboratory studies does not rule out possible psychosocial effects of regular exercise on the frequency and duration of the stress reactions in real-life situations. Furthermore, although the dynamics of the physiological response to stress are not changed, there is a clear downward shift in the overall level of heart rate and blood pressure in stressful situations. Several possible mechanisms are suggested by which these training effects may help us to deal with work stress without suffering health problems.     

The effects of coauthorship on the quality of financial research papers

This paper analyzes whether formal collaboration in terms of coauthorship enhances paper quality in financial research. Analyzing all papers presented at DGF annual meetings in the period from 1996 to 2005, we report the following major findings: First, we find superior paper quality of coauthored papers compared to single-authored papers. This holds true for two quality proxies, publication probability and publication quality (as measured by the original and the updated Jourqual rating). Second, the capability of scholars, measured by a citation measure derived from citations in Google Scholar, shows to be an additional important factor for explaining paper quality. Third, the employed methodology of a paper (e.g., empirical analysis, theoretical analysis) does not systematically affect paper quality. However, it is important to differentiate between empirical and theoretical papers. Whereas coauthorship shows to be a quality enhancing factor for empirical papers, this does not hold true for theoretical papers. Fourth, the origin of data is a crucial determinant of the publication success for empirical papers. In particular, papers which exclusively analyze data from Germany are published in less reputable journals.     

The effects of self-efficacy on computer usage

This paper examines the effect of self-efficacy, belief in one's capabilities of using a computer in the accomplishment of specific tasks, on computer usage. It introduces an extended technology acceptance model (TAM) that explicitly incorporates self-efficacy and its determinants (experience and organizational support) as factors affecting computer anxiety, perceived ease of use, perceived usefulness and the use of computer technology. A survey of 450 microcomputer users in Finland found strong support for the conceptual model. In accordance with TAM, perceived usefulness had a strong direct effect on usage, while perceived ease of use had indirect effect on usage through perceived usefulness. Self-efficacy had both direct and indirect effects on usage, demonstrating its importance in the decision to use computer technology. It also had a strong direct effect on perceived ease of use, but only an indirect effect on perceived usefulness through perceived ease of use. Computer experience was found to have a strong positive direct effect on self-efficacy, perceived ease of use, perceived usefulness and usage. Organizational support and computer anxiety had only indirect effects on usage, mainly through perceived usefulness. Implications of these findings are discussed for researchers and practitioners.     

The effects of regulatory tools on organizational populations

One of the main activities of regulation is the control of market development by influencing the number of firms in an industry, their entry into an industry, and their exit from an industry. Population ecology is used as a framework for explaining both the direct and indirect effects of regulatory activity on entry, exit, and market structure. This framework is then used to derive specific propositions about regulatory effects on entry, exit, and market structure in the health maintenance organization industry.     

The effects of seasonal demand on depot location

Many of the cost functions associated with depot location algorithms assume an overall demand for a fixed period, usually one year. This paper describes an investigation into the effect of high seasonality within such demand figures on the optimal location of storage facilities. The preliminary results indicate that a more flexible approach for certain products could be worthwhile.     

The effects of leadership style on stress outcomes

The present study manipulated transformational and transactional leadership styles to examine their influence on individuals' performance on a stressful task, and on perceived social support, self-efficacy beliefs, emotions, and stressor appraisals. In addition, this study examined whether these variables mediated the relationship between leadership style and performance. Two hundred fourteen participants viewed video instructions for a stressful task presented by an actor depicting one of three leadership styles (transformational, transactional-contingent reward, and transactional-management by exception). Participants' psychological, emotional, and motivational responses to the videos were assessed prior to their engagement with the task. The transformational leadership condition was associated with enhanced task performance, higher social support perceptions, greater efficacy beliefs, lower negative affect, and lower threat appraisals compared to the transactional conditions. Causal modeling revealed that leadership style had a direct, rather than indirect, effect on task performance. The present research extends leadership research by providing an experimental evaluation of the costs/benefits of transformational and transactional leadership under stressful task conditions. Some of the results parallel those from correlational field studies, thus corroborating transformational leadership theory while other results diverge from theory, but present opportunities for future research.     

The effects of state-dependent human behavior on the design of a serial line

Most research on line design assumes that human operators perform independently from the status of the line. Recent empirical evidence is contradictory. Humans are likely to change their working speed if they might otherwise cause idle time (Schultz et al., Manage Sci 44(12):1595–1607, 1998). This peculiarity of worker behavior is observed in a variety of settings but little is still known about optimal line design that accounts for this more realistic modeling of worker behavior. Therefore, we analyze work allocation in a serial line with limited buffer capacity and adaptive human behavior. An extensive simulation study reveals that optimal work allocation in state-dependent models is different from classical state-independent models. A bowl-shaped work allocation might be suboptimal and design guidelines are more complicated. Depending on the extent of human reactions, a bowl-shaped, balanced, or reversed-bowl work allocation can be preferable.     

信息技术投资对零售市场均衡的影响分析

从一个基本模型出发,考察了没有IT投资的零售市场定价、市场份额和利润.然后考察有IT投资的零售市场,考虑搜索成本变化时的定价、市场份额和利润.最后,考察不同进货成本的零售商IT投资的条件及其市场均衡.     

投资者彩票偏好对股票价格行为的影响研究

首次使用百度搜索指数来度量我国股市投资者的彩票偏好程度,并从市场整体层面研究了投资者彩票偏好对股市收益及其波动的影响.分析了和彩票销售数据的相关性,结果表明彩票偏好指数是有效的.随后使用巨潮系列规模指数进行实证研究后发现:投资者彩票偏好会显著降低滞后1期的股市收益率,这种影响在中、小盘股票中体现得尤为明显;对波动率的影响方面,彩票偏好会显著降低小盘股的当期波动率,并且这种影响主要是通过移动端体现出来的,表明不同端口投资者的彩票偏好对股票价格行为的影响存在异质性.使用上证A股系列指数进行的稳健性检验发现实证结果是基本一致的.     

The moderating effects of value similarity and company philosophy on the climate-commitment relationship

The present study examines the moderating effects of two components of culture (value similarity and company philosophy) on the relationship between organizational climate and commitment. Moderator regression analyses reveal that value similarity has a direct effect on levels of commitment but does not moderate the climate-commitment relationship. In contrast, company philosophy is found to affect commitment directly but also to moderate the relationship between the reward and consideration dimensions of climate and organizational commitment. The results provide support for a culture-based explanation of commitment and offer some insights into the linkage between climate and organizational culture.     

The importance of self-efficacy in the moderating effects of social support on stressor-strain relationships

Occupational stress research offers inconsistent findings on the moderating effects of social support on the stressor-strain relationship. This study contributes to the research literature by examining how social support's moderating effect is dependent on one's self-efficacy. Ninety-six US military police soldiers completed two surveys 3 months apart. The results showed that three out of four regression equations had significant three-way interactions. Organizational constraints×supervisor support×self-efficacy had statistically significant interactions in the prediction of job satisfaction and psychological well-being. Organizational constraints×co-worker support×self-efficacy had a significant interaction in the predicted of psychological well-being. These interactions explained between 5% and 10% of the variance in the dependent variables. Social support buffered the stressor-strain relationship when self-efficacy was high and reverse buffered the relationship when self-efficacy was low. These results indicate that interventions aimed at reducing strains by increasing social support should consider an individual's self-efficacy. Future research should consider incorporating content of communication to determine if high and low self-efficacy individuals receive or react differently to different types of communication content.     

The effects of leadership change on team escalation of commitment

Although teams benefit from developing plans and processes that boost efficiency and reduce uncertainty, they may become too attached to these plans and escalate commitment when an alternative response is needed. Drawing on theories of team leadership, team processes and escalation of commitment, we propose that a change in leadership can help the team reduce commitment to outdated plans and avoid further escalation over time. Across two studies, we tested and found support for our hypotheses and provide evidence that leadership change can break the cycle of escalation by enhancing leader-driven team reflection and refocusing the team on error correction instead of additional investment. We discuss how the results of these studies extend existing theory and add to our understanding of the important role leaders play in enhancing team adaptation and preventing team escalation.     

Conjoint effects of interacting strategy-making processes and lines of defense practices in strategic Risk Management: An empirical study

The ability to contain adverse effects of major risks under turbulent conditions and exploit the opportunities they present are fundamental concerns in strategic management and various institutions promote enterprise risk management (ERM) to deal with these challenges. Yet, our knowledge about how ERM affects performance and interacts with corporate strategy-making processes is limited. The ERM frameworks impose first and second lines of defense practices to integrate business operations and corporate risk oversight. Emergent strategies generate responsive initiatives and strategic planning coordinates updated actions. Hence, this study analyzes the conjoint effects of these ERM practices and strategy-making processes based on a large corporate sample and finds that ERM practices depend on strategy-making to attain effective risk outcomes. The application of ERM frameworks can, therefore, not be assessed in isolation, but must consider corporate strategy-making. This has implications for the way we conduct research on strategic risk management, how executives approach risk oversight and policy-makers impose formal risk governance requirements.     

不公正评价对在线交易的影响和作用机理研究

现有理论认为,不公正评价的存在会降低卖家的合作动机和市场效率.本文用实验法对比研究了三个不同的在线交易市场,即无评价市场,公正评价市场和不公正评价市场.实验发现,不公正评价对买家和卖家的整体行为以及在线交易市场的影响并不显著,基于评价的信誉机制仍然是有效的.研究发现,不公正评价会引发买家的“自校正”行为和“个人经验倚重”行为,从而减弱了它对买家的干扰;同时,不公正评价会对卖家产生“诱导”和“督促”双重作用,它们的效果相反,导致不公正评价对卖家的影响亦十分有限.     

The economic effects of large industrial undertakings on rual economies

This paper uses an adaptation of the input-output method to test the impact of large-scale industrial undertakings on comparatively small and sparsely-populated areas. It explains how, firstly, a model was built based upon a specimen rural area and including a series of vectors which allow local demand to change as incomes change. The model was then generalized so that data could be inserted to simulate any similar area. The paper then explains the results obtained from inserting a large-scale industrial activity into the model.     

The hypothesized effects of ability in the turnover process

Findings from studies that have investigated the relationship between task-relevant ability and turnover have been inconsistent. A process model is presented that suggests that ability may be related to turnover through the individual's perception of both the ease and desirability of movement. The potential effect of ability on the turnover process and its practical and theoretical implications are discussed.