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The purpose of this paper is to investigate the performance of unpaced reliable production lines that are unbalanced in terms of their mean operation times, coefficients of variation and buffer capacities.

Simulations were carried out for five‐ and eight‐station lines with various buffer capacities and degrees of means imbalance. Throughput, idle time and average buffer level performance indicators were generated and statistically analysed.

The results show that an inverted bowl allocation of mean service times, combined with a bowl configuration for coefficients of variation and a decreasing order of buffer sizes results in higher throughput and lower idle times than a balanced line counterpart. In addition, considerable reductions in average inventory levels were consistently obtained when utilizing a configuration of progressively faster stations, coupled with a bowl‐shaped pattern for coefficients of variation and an ascending buffer size order.

The results for these specific experiments imply that resources expended on trying to achieve a balanced line could be better used by seizing upon possible enhanced performance via controlled mean time, variability and buffer imbalance. Results are valid for only the line type and parameter values used (simulation results are specific and not general).

Guidelines are provided on design strategies for allocating labour and capital unevenly in unpaced lines for better performance in terms of increased throughput or lowered idle time or average buffer levels.

This paper might be viewed as one of the first simulation investigations into the performance of unpaced production lines with three sources of imbalance.

The purpose of this paper is to develop a computer simulation model to evaluate the bowl phenomenon and the allocation at the end of the line of stations with either greater mean operation times or higher variability of operation times.

The model was developed on the basis of a realistic case problem and applied to a six‐station assembly line. The evaluation criteria were the: minimization of the total elapsed time; maximization of the average percentage of working time; and minimization of the average time in the system.

The performance of an assembly line with independently normally distributed operation times could be improved by applying the bowl phenomenon. The allocation of large operation mean times to stations located near the end of the line did not produce improved results. Instead a more balanced allocation proved to be more significantly effective. On the other hand, the assignment of larger variability of operation times to the stations near the end of the line improved the performance of the assembly line.

The investigation contributed to the computer simulation approach to solving assembly line problems that dealt with the impact of normally distributed operation times on the bowl phenomenon and assembly lines with increasing mean operation times and higher variability of operation times at the end of the line of stations.

Consultant commissions in two envelope fee bidding are awarded on the basis of fee and quality (i.e. technical score). Consultants' fees and technical score are combined using a pre‐designated formulation and predetermined weightings to form a total score. Procurers seem to be having difficulties with existing formulations in controlling the extent to which two envelope fee competitions are dominated by fees. This is because, in most cases, fees vary more than technical scores and the predetermined weightings applied are not sufficient to correct the variability imbalance. The analysis in this paper shows that in fee dominant competitions lower fee‐lower technical scoring consultants are more likely to be successful in winning commissions. The analysis shows that this can be corrected by balancing fees and technical score. Although procurers are likely to pay higher fees when balancing fees and technical scores they normally benefit from getting higher technical scoring consultants.

As exposure to psychosocial hazard at work represents a substantial risk factor for employee health in many modern occupations, being able to accurately assess how employees cope with their working environment is crucial. The workplace is generally accepted as being a dynamic environment, therefore, consideration should be given to the interaction between employees and the acute environmental characteristics of their workplace. The purpose of this paper is to investigate the effects of both acute demand and chronic work-related psychosocial hazard upon employees through ambulatory assessment of heart rate variability and blood pressure.

A within-subjects repeated measures design was used to investigate the relationship between exposure to work-related psychosocial hazard and ambulatory heart rate variability and blood pressure in a cohort of higher education employees. Additionally the effect of acute variation in perceived work-related demand was investigated.

Two dimensions of the Management Standards were found to demonstrate an association with heart rate variability; more hazardous levels of “demand” and “relationships” were associated with decreased standard deviation of the normal-to-normal interval. Significant changes in blood pressure and indices of heart rate variability were observed with increased acute demand.

This is the first attempt to combine the Health and Safety Management Standards Indicator Tool with physiological assessment of employees. The results provide evidence of associations between scores on the indicator tool and ambulatory heart rate variability as well as demonstrating that variation in acute perceived work-related demand is associated with alterations to autonomic and cardiovascular function. This has implications not only for employee health and workplace design but also for future studies employing ambulatory physiological monitoring.

Early involvement of the construction team is increasingly utilized in demanding projects to incorporate versatile expertise in their planning. For public owners this is a challenge since they are obliged to use competitive, transparent team selection based on the ‘most economically advantageous’ criterion which ensures that both price and quality viewpoints are taken into account. In the case of early involvement, the price component naturally does not include the total price, but may consist only of the fee-percentages of competing service providers. This study examines such a selection situation in project alliancing in the European context and seeks to find a way to integrate the fee component in a multi-criteria selection system and determine reasonable fees for different levels of capabilities. The study builds on the performance difference between different capabilities, derived from a survey of practitioners, and determines an indifference curve arithmetically for the planning of a selection method. The influence of the owner‘s risk attitude and risk premiums are also considered exploratively based on the pricing methods of the theory of finance.

A comprehensive analysis of a flexible hybrid assembly system (FHAS) where automated devices and human operators interact is presented. A computer simulation programme and ANOVA were conducted to identify which factors significantly affect the measures of performance of the system. The results clearly indicated that certain factors have a more significant effect on the measures of performance than the others. A classification of the relative significance of input factors affecting such a system is made. In order to investigate the generality of the results, alternative station configurations and factor levels are examined. The outcome shows that the results are applicable to different configurations of FHAS.

The purpose of this paper was to investigate the physiological cost of concrete construction activities.

Five concrete construction workers were recruited. The workers’ three-week heart rate (HR) data were collected in summer and autumn. In this paper, several HR indexes were used to investigate the physiological cost of work in concrete construction trades, including average working HR, relative HR and ratio of working HR to resting HR.

This paper measures how absolute and relative HRs vary throughout a workday and how working HR compares to resting HR for individual workers.

Field observations are usually extremely difficult as researchers need to overcome a number of barriers, including employers’ resistance to perceived additional liabilities, employees’ fear that their level of activity will be reported to managers and many other practical and technical difficulties. As these challenges increase exponentially with the number of employers, subjects and sites, this study was limited to a small number of subjects all working for the same employer on the same jobsite. Still, challenges are often unpredictable and lessons learned from this study are expected to guide both our and other researchers’ continuation of this work.

The time effect on the physiological cost of work has not been considered in previous studies. Thus, this study is noteworthy owing to the depth of the data collected rather than the breadth of the data.

This paper briefly reviews the assembly line balancing techniques developed over the last 30 years. It attempts to establish the direction of research, to identify unexplored areas with potential for study and recommends future courses of action.

As drones are rapidly transforming tasks such as mapping and surveying, safety inspection and progress monitoring, human operators continue to play a critical role in ensuring safe drone missions in compliance with safety regulations and standard operating procedures. Research shows that operator's stress and fatigue are leading causes of drone accidents. Building upon the authors’ past work, this study presents a systematic approach to predicting impending drone accidents using data that capture the drone operator's physiological state preceding the accident.

The authors collect physiological data from 25 participants in real-world and virtual reality flight experiments to design a feedforward neural network (FNN) with back propagation. Four time series signals, namely electrodermal activity (EDA), skin temperature (ST), electrocardiogram (ECG) and heart rate (HR), are selected, filtered for noise and used to extract 92 time- and frequency-domain features. The FNN is trained with data from a window of length t = 3…8 s to predict accidents in the next p = 3…8 s.

Analysis of model performance in all 36 combinations of analysis window (t) and prediction horizon (p) combinations reveals that the FNN trained with 8 s of physiological signal (i.e. t = 8) to predict drone accidents in the next 6 s (i.e. p = 6) achieved the highest F1-score of 0.81 and AP of 0.71 after feature selection and data balancing.

The safety and integrity of collaborative human–machine systems (e.g. remotely operated drones) rely on not only the attributes of the human operator or the machinery but also how one perceives the other and adopts to the evolving nature of the operational environment. This study is a first systematic attempt at objective prediction of potential drone accident events from operator's physiological data in (near-) real time. Findings will lay the foundation for creating automated intervention systems for drone operations, ultimately leading to safer jobsites.

Modern life is characterized by its hectic life-style, which invariably leads to high levels of stress having negative consequences for the mind-body. Thus, people are seeking for natural ways to achieve a sense of equilibrium and peace. Neuroscience has identified beneficial findings from contemplative practices like meditation, prayers and fasting. Within the Islamic framework, these practices were found to be beneficial for both the body and the mind. However, comparatively little research has been carried out on Islamic contemplative practices. Thus, there is a dire need to carry out further research, where the focus needs to be more on the inward aspects of Islam especially the contemplative practices.

The study took an integrated approach, whereby, objective experimental data from various sources were combined with the religious narratives from the Qur’an and the Hadiths or the practice of the Prophet in Islam. This was augmented by the subjective experiences of the participants of the study and all of these woven to present a case for Islamic contemplative practices.

Worship, be it Yogic, Buddhist and Islamic, seems to have positive mental and physical benefits for individuals. Much has been documented within the field of Yoga and Buddhist practices, and it is only recently that Islamic practices are beginning to be studied and are yielding similar results. It has been found that Islamic ritual prayers, fasting and meditation (dhikr) have an impact on the well-being of the worshipper. The communities of practice commonly known as “tariqas” and other religio-spiritual orders can serve as a vehicle to further these practices. This opens the door for more extensive research in this direction.

This study clearly indicates that Islamic practices have positive benefits; however, the number of studies are limited. Moreover, there are a whole system of practices as the contemplative tree in this paper points out, which needs more robust as well as longitudinal studies to outline more conclusive evidence to this effect.

Muslims have been looking at other traditions like Yoga and Buddhist meditation to find ways of improving their physical and mental health. This meta-study indicates that Islamic contemplative practices have positive benefits, and thus, there are a variety of practices like ritual prayers, fasting and meditation, which is found to demonstrate positive health benefits. Thus, it has direct practical reasons to pursue these practices and derive the innate benefits from them.

The data from the various neuroscience studies have demonstrated the neurological and physiological impact on individuals directly relating to worship. However, the studies on the Islamic ritual prayer (salat) cited in this study points out to its social implications, where congregational prayers was found to be more beneficial than the individual prayers. Thus, this indicates the social implications that collective worship can have. Further research is needed in terms of understanding the social impact on the various collective contemplative practices.

The originality of this literature review and analysis is bringing together the various strands of neuroscience and health data to demonstrate the positive impact of worship emanating from others faiths, while building a case for Islamic contemplative practices. This is further augmented by its integrated approach of weaving hard and soft data and synthesizing it to present health benefits of worship.