Attention and complacency

The problem of complacency is analysed, and it is shown that previous research that claims to show its existence is defective, because the existence of complacency can not be proved unless optimal behaviour is specified as a benchmark. Using gedanken experiments, it is further shown that, in general, not even with optimal monitoring can all signals be detected. Complacency is concerned with attention (monitoring, sampling), not with detection, and there is little evidence for complacent behaviour. To claim that behaviour is complacent is to blame the operator for failure to detect signals. This is undesirable, since so-called complacent behaviour may rather be the fault of poor systems design.     

Automation-induced complacency for monitoring highly reliable systems: the role of task complexity,system experience,and operator trust

The increase in quantity and complexity of advanced automated systems has generated new concerns surrounding automation-induced complacency, or the difficulties operators have monitoring the status of automated systems. The present investigation consists of two studies that assessed the impact of system reliability, monitoring complexity, operator trust, and system experience on automation-induced complacency. In both studies, participants operated a manually controlled flight task while monitoring several simulated aircraft displays for failures. The ability of operators to detect a single automation failure over three experimental sessions was also assessed. Results indicated that realistic levels of system reliability severely impaired an operator's ability to monitor effectively. Further, as system experience increased, operator monitoring performance declined. The results also indicated that the complexity of the monitoring task heavily influenced operator monitoring, with poorer performance associated with more cognitively demanding tasks. Finally, results from both studies indicated that operator trust increased and monitoring performance decreased as a function of increasing system reliability. These results suggest that for highly reliable systems, increasing task complexity and extensive experience may severely impair an operator's ability to monitor for unanticipated system states.     

The 'ergonomics paradigm': Foundations,challenges and future directions

The challenges confronting the multi-disciplinary human factors and ergonomics profession are rapidly growing as the pace of technological change redefines the way in which people interact with each other at work and at play. Areas such as human-computer interaction, cognitive ergonomics and information technology management are booming. Calls for greater influence on designing for teams and other large groups of people, i.e. macroergonomics are growing rapidly. All the while, physical ergonomics (e.g. occupational biomechanics, manual materials handling) continues to be a strong focus in the US and around the world. To keep pace with these challenges, each human factors professional should understand the history of the field, remember the complexity of the 'user' and be able to see how their efforts unify and expand the ergonomics discipline. This paper reviews the development of the ergonomics paradigm, explores the challenges confronting the ergonomics discipline and presents ways in which those challenges may be addressed using methodologies familiar to human factors practitioners and researchers.     

Human work in call centres: A challenge for cognitive ergonomics

Many people are currently working in call centres and much more are expected to work in them in the near future. Call centres are, in a sense, 'modern factories' where services are delivered through information and communication technologies. The human activity within the dynamic and articulated reality of such work settings offers new challenges for cognitive ergonomics. Indeed, work in call centres has to be conceptualized in terms of distributed knowledge. This means that only part of the knowledge needed to carry out any transaction is (or rather has to be) in the mind of the operator; relevant knowledge may be distributed among colleagues in the organization, available and accessible cognitive artefacts in the work environment, and clients. This paper discusses the potential contribution that human factors and cognitive ergonomics can provide in tackling the new and old problems that emerge in organizations where knowledge is an asset.     

Multidisciplinary perspective on accident investigation

The increasing complexity of many computer-controlled application processes is placing increasing demands on the investigation of adverse events. At the same time, there is a growing realisation that accident investigators must consider a wider range of contributory and contextual factors that help to shape human behaviour in the causes of safety-related incidents. A range of techniques have been developed to address these issues. For example (as we show in this paper), task modelling techniques have been extended from human computer interaction and systems design to analyse the causes and consequences of operator ‘error’. Similarly, barrier analysis has been widely used to identify the way in which defences either protected or failed to protect a target system from potential hazards. Many barriers fail from common causes, including misconceptions that can be traced back to early stages in the development of a safety-critical system. For instance, unwarranted assumptions can be made about the impact of training on operator behaviour in emergency situations. Similarly, barrier analysis can also be used before a system has been designed to inform the system model and make it more tolerant to errors by incorporating human and technical barriers into the design. Task models often uncover deep-rooted problems, for instance, in workload allocation across many different aspects of an interactive control system. It can be difficult to use barrier and task analysis to trace these common causes that lie behind the failure of many different defences. In order to deal with this complex combination of contributory factors and systems, we promote the use of abstraction (via models) as a way of representing these components and their interrelations whether it is design, construction or investigation. We use, to formally model an abstraction of the system. Additionally, the system model (described using a dialect of high-level Petri-nets) allows to reason about the system and to check conformance with the other models (task model, safety case and barriers). This paper, therefore, shows how an analysis of safety case arguments can be used to support the application of barrier, task, error and system analysis during the investigation of a command and control failure. The intention, in this paper, is to show that if an accident involved the failure of multiple barriers, it is also possible to trace the common causes of those failures back to the assumptions and arguments that are embodied within a safety case. Many countries require that safety cases demonstrate a system is ‘acceptably safe’ before they grant regulatory approval. These documents and the associated analytical techniques, therefore, provide a rich source of information about why command and control failures occurred. We demonstrate our approach on a fatal mining accident case study.     

Phase properties of operator valued measures in phase space

Abstract

The Wigner phase operator (WPO) is identified as an operator valued measure (OVM) and its eigenstates are obtained. An operator satisfying the canonical commutation relation with the Wigner phase operator is also constructed and this establishes a Wigner distribution based operator formalism for the Wigner phase distribution. It is then argued that the WPO cannot represent a projective measurement of the phase; but is in fact to be interpreted as an operator valued measure for the phase. The non-positivity of the latter can be overcome by defining a positive operator valued measure (POVM) via a proper filter function, based on the view that phase measurements are coarse-grained in phase space, leading to the well known Q-distribution. The identification of the Q phase operator as a POVM is in good agreement with the earlier observation regarding the relation between operational phase measurement schemes and the Q-distribution. The Q phase POVM can be dilated in the sense of Gelfand–Naimark, to an operational setting of interference at a beam-splitter with another coherent state – this results in a von Neumann projector with well-defined phase in the expanded Hilbert space of the two modes.     

How does a collision warning system shape driver's brake response time? The influence of expectancy and automation complacency on real-life emergency braking

Brake Reaction Time (BRT) is an important parameter for road safety. Previous research has shown that drivers' expectations can impact RT when facing hazardous situations, but driving with advanced driver assistance systems, can change the way BRT are considered. The interaction with a collision warning system can help faster more efficient responses, but at the same time can require a monitoring task and evaluation process that may lead to automation complacency. The aims of the present study are to test in a real-life setting whether automation compliancy can be generated by a collision warning system and what component of expectancy can impact the different tasks involved in an assisted BRT process. More specifically four component of expectancy were investigated: presence/absence of anticipatory information, previous direct experience, reliability of the device, and predictability of the hazard determined by repeated use of the warning system. Results supply indication on perception time and mental elaboration of the collision warning system alerts. In particular reliable warning quickened the decision making process, misleading warnings generated automation complacency slowing visual search for hazard detection, lack of directed experienced slowed the overall response while unexpected failure of the device lead to inattentional blindness and potential pseudo-accidents with surprise obstacle intrusion.     

A population based estimation of the driver protection provided by passenger cars: France 1996–2005

The technology used in cars to protect occupants is constantly developing. Demonstrating the beneficial effects in the field is complex as the most recent vehicles are generally used by drivers who differ from other drivers and who drive in different traffic conditions. This paper presents an overall estimation of the consequences of changes in the secondary safety of cars, taking account of most of these factors.The data come from information collected about injury road traffic crashes by the police in France between 1996 and 2005. The risk of the driver being killed has been evaluated for the 144,034 drivers involved in two-car crashes and for the 63,621 drivers involved in single-car crashes.The study shows that when a recent car is in collision with an older car the driver of the former is better protected than the driver of the latter. These improvements in secondary safety are not observed in the case of single-car crashes, very probably because of higher impact speeds. Our findings also confirm the need for protection systems to be better adapted to the specific characteristics of users and for an improvement in the crash compatibility of vehicles, in particular to overcome the consequences of differences between the masses of vehicles.     

Does the concept of safety culture help or hinder systems thinking in safety?

The concept of safety culture has become established in safety management applications in all major safety-critical domains. The idea that safety culture somehow represents a “systemic view” on safety is seldom explicitly spoken out, but nevertheless seem to linger behind many safety culture discourses. However, in this paper we argue that the “new” contribution to safety management from safety culture never really became integrated with classical engineering principles and concepts. This integration would have been necessary for the development of a more genuine systems-oriented view on safety; e.g. a conception of safety in which human, technological, organisational and cultural factors are understood as mutually interacting elements. Without of this integration, researchers and the users of the various tools and methods associated with safety culture have sometimes fostered a belief that “safety culture” in fact represents such a systemic view about safety. This belief is, however, not backed up by theoretical or empirical evidence. It is true that safety culture, at least in some sense, represents a holistic term—a totality of factors that include human, organisational and technological aspects. However, the departure for such safety culture models is still human and organisational factors rather than technology (or safety) itself. The aim of this paper is to critically review the various uses of the concept of safety culture as representing a systemic view on safety. The article will take a look at the concepts of culture and safety culture based on previous studies, and outlines in more detail the theoretical challenges in safety culture as a systems concept. The paper also presents recommendations on how to make safety culture more systemic.     

Augmenting defense-in-depth with the concepts of observability and diagnosability from Control Theory and Discrete Event Systems

Defense-in-depth is a fundamental principle/strategy for achieving system safety. First conceptualized within the nuclear industry, defense-in-depth is the basis for risk-informed decisions by the U.S. Nuclear Regulatory Commission, and is recognized under various names in other industries (e.g., layers of protection in the Chemical industry). Accidents typically result from the absence or breach of defenses or violation of safety constraints. Defense-in-depth is realized by a diversity of safety barriers and a network of redundancies. However, this same redundancy and the intrinsic nature of defense-in-depth - the multiple lines of defense or “protective layers” along a potential accident sequence - may enhance mechanisms concealing the occurrence of incidents, or that the system has transitioned to a hazardous state (accident pathogens) and that an accident is closer to being released. Consequently, the ability to safely operate the system may be hampered and the efficiency of defense-in-depth may be degraded or worse may backfire. Several accidents reports identified hidden failures or degraded observability of accidents pathogens as major contributing factors.In this work, we begin to address this potential theoretical deficiency in defense-in-depth by bringing concepts from Control Theory and Discrete Event Systems to bear on issues of system safety and accident prevention. We introduce the concepts of controllability, observability, and diagnosability, and frame the current understanding of system safety as a “control problem” handled by defense-in-depth and safety barriers (or safety constraints). Observability and diagnosability are information-theoretic concepts, and they provide important complements to the energy model of accident causation from which the defense-in-depth principle derives. We formulate a new safety-diagnosability principle for supporting accident prevention, and propose that defense-in-depth be augmented with this principle, without which defense-in-depth can degenerate into a defense-blind safety strategy. Finally, we provide a detailed discussion and illustrative modeling of the sequence of events that lead to the BP Texas City Refinery accident in 2005 and emphasize how a safety-diagnosable architecture of the refinery could have supported the prevention of this accident or mitigated its consequences. We hope the theoretical concepts here introduced and the safety-diagnosability principle become useful additions to the intellectual toolkit of risk analysts and safety professionals and stimulate further interaction/collaboration between the control and safety communities.     

Individual latent error detection: is there a time and a place for the recall of past errors?

A task carried out in error creates a latent condition that can result in a future undesirable outcome if the error is not detected later. The paper presents a study of the relatively under-researched phenomenon of post-task latent error detection. Focusing on UK naval aircraft maintenance, it was hypothesised that time, location and systems cues influence individual latent error detection amongst naval air engineers who experience the phenomenon. The systems view of human error is combined with a multi-process approach to post-task latent error research, for which findings suggest that distributed cognition across the entire socio-technical system may be influential in post-task latent error detection. Directions for future research will be of benefit to those interested in furthering safety resilience using a systems approach to minimise the consequences arising from latent error.

Relevance to human factors/ergonomics theoryThe nature and extent of post-task latent error detection is explored using a systems approach, for which distributed cognition across the entire socio-technical system appears influential. The aim of current research is to develop interventions to further mitigate for latent errors and thus advance the systems application of ergonomics theory.     

Analysis of fault tolerance and reliability in distributed real-time system architectures

Safety critical real-time systems are becoming ubiquitous in many areas of our everyday life. Failures of such systems potentially have catastrophic consequences on different scales, in the worst case even the loss of human life. Therefore, safety critical systems have to meet maximum fault tolerance and reliability requirements. As the design of such systems is far from being trivial, this article focuses on concepts to specifically support the early architectural design. In detail, a simulation based approach for the analysis of fault tolerance and reliability in distributed real-time system architectures is presented. With this approach, safety related features can be evaluated in the early development stages and thus prevent costly redesigns in later ones.     

Towards a transactional ergonomics for driver stress and fatigue

This article reviews a transactional model of driver stress and fatigue, and its ergonomic application to designing vehicle systems for 'stress-tolerance'. Disturbances of subjective state are controlled by cognitive stress processes of appraisal and coping. Both personality factors and situational stressors may elicit maladaptive patterns of cognition that generate subjective stress symptoms, elicit potentially dangerous coping strategies, and interfere with information-processing and attention to the task at hand. Studies using a driving simulator have explored the behavioural consequences of several qualitatively different forms of 'stress', that can be loosely labelled as anxiety, anger and fatigue. Implications of the model for design are reviewed, focusing on road engineering, in-car systems, and automation of vehicle functions. A transactional analysis focuses on evaluation of the cognitions produced by vehicle systems, problems of distraction and overload, and maintaining active task involvement. The article concludes with guidelines for design to minimize safety problems associated with stress and fatigue.     

Employee engagement,boredom and frontline construction workers feeling safe in their workplace

Systems thinking is a philosophy currently prevalent within construction safety literature that is applied to understand and improve safety in sociotechnical systems. Among systems, the site-project organizational system is of particular interest to this paper. Using focus group and survey feedback research to learn about how safety incidents effect levels of construction workers engagement this paper reveals how a safety incident provides an opportunity to create a potential quality (productivity) upgrade within an organization. The research approach involved a qualitative study involving 27 frontline supervisors and a follow-up survey completed by 207 frontline workers in the Australian Asphalt and Pavement Industry. The focus group interviews supported the articulation of the concepts of tacit safety, explicit safety, situational awareness, foresight ability, practical intelligence and crew synergy. Our findings indicate that having regular shift changes and other job site workers being fatigued are influential on perceptions of tacit safety. An individual's foresight ability was found to be the most potent predictor of worker perceptions of work engagement. The paper explains that relatively small improvements in worker perceptions of safety can bring about significant improvements in employee engagement and productivity.     

An overview of LULU operators and discrete pulse transform for image analysis

Abstract

This paper presents an overview of LULU operators and discrete pulse transform (DPT). Data extraction from signals and images is a popular area of research. Different methods are being used for data extraction such as different types of linear and nonlinear operators. LULU operator is one of the most important rank selector nonlinear filters used for data analysis which is widely being used for signal analysis, especially in impulse noise filtering. It is computationally more efficient and the behaviour of the operator is simple to describe. Based on the composition of different orders of LULU operators, DPT on multi-resolution is defined, which describes the sequences into pulses with different magnitudes. DPT allows a multi-resolution measure of roughness of images and sequences. It is a powerful technique for image analysis and can also be used for the estimation of standard deviation of a random distribution.     

招贴设计中的简约主义风格

目的探究招贴设计中的简约主义风格。方法以简约主义风格为起点,概括简约主义风格融入招贴设计的重要意义,在此基础上分文字、构图、色彩、图形4个方面对招贴设计中的简约主义风格进行论述,配合具体实例总结方式方法。结论在招贴设计中融入简洁主义风格既能够满足大众的精神需求,又能够提升招贴作品的宣传效果,是未来招贴设计的主要发展趋势。     

Chemical Enhancers for the Absorption of Substances Through the Skin: Laurocapram and Its Derivatives

ABSTRACT

Absorption enhancers are substances used for temporarily increasing a membrane's permeability (e.g., the skin and mucosa), either by interacting with its components (lipids or proteins) or by increasing the membrane/vehicle partition coefficient. This article presents the results of biophysical and permeability studies performed with Laurocapram and its analogues. As shown, Laurocapram and its analogues present different enhancing efficacies, for most of both hydrophilic and lipophilic substances. The enhancing effect of Laurocapram (Azone®) is attributed to different mechanisms, such as insertion of its dodecyl group into the intercellular lipidic bilayer, increase of the motion of the alkylic chains of lipids, and fluidization of the hydrophobic regions of the lamellate structure. Toxicological studies reveal a low toxicity for Laurocapram, and for some derivatives, a relationship exists between toxicity and the number of carbons in the alkylic chain. Very important, when applied to human skin, Laurocapram shows a minimal absorption, being quickly eliminated from circulation. However, although Laurocapram and its derivatives have been shown to provide enhancement, they have not been widely accepted because of their suspected pharmacological activity or questions about their safety.     

Representing context, cognition, and crew performance in a shutdown risk assessment

This paper presents a potentially practical treatment of dynamic operator-system interactions. The approach employs a dynamic event tree framework to explicitly address plant dynamics, system indications, crew-plant interactions, time available, crew cognition, errors of commission (mistakes), and multiple planning and diagnosis possibilities. The approach is applied in an analysis of a hypothesize medium break loss of coolant accident for a test reactor that occurs during plant shutdown. This transient was selected on the basis of: a significant cognitive component being present, high consequences being associated with operator actions, and the importance of event timing to scenario progression. The results presented show how quantitative risk predictions are affected by the treatment of dynamics, and demonstrate how non-proceduralized recovery actions and a number of performance shaping factors (e.g., crew experience, stress, and confidence) can be explicitly treated. Insights and lessons learned regarding the performance of a dynamic assessment are also presented.     

Automated Torque Sensing Equipment for Cosmetics and Pharmaceuticals

Abstract

The limited accuracy of existing closure torque testers and the subjectivity of the measurements imparted by human operators has led to the development of an automated closure testing machine, the Auto-Torque.

As packaging requirements become more stringent in order to provide Improved consumer safety and product integrity, improved quality control techniques become necessary. Torque testing of closures has relied for years on a manually operated spring scale with a claimed accuracy of plus or minus four percent (4%) full scale. The closure testing process becomes more inaccurate when you add to this error the inconsistencies due to reading errors, data entry/analysis errors, and operator technique (1). Automation of the closure torque testing process narrows the range of errors down to those of the machine itself which are easily quantified by a calibration procedure.

Currently available spring scale closure testers have no provision for measuring downward force needed to engage child-resistant (CR) closures, requiring the user to develop their own apparatus (2). Currently, the Auto-Torque is being used for university research and by major pharmaceutical companies in both the package development and quality assurance test area to support the productivity of multiple lines.

This paper describes the Auto-Torque's ability to provide the quality assurance needed In the closure torque testing process. Technical problems encountered and their solutions are viewed from a general systems automation perspective.     

Management Issues in Engineer Supply

ABSTRACT

This article presents the authors' research on quantifying trends in the future supply of professional engineers in Australia. Predictions are made concerning the effects of demographic change in the Australian population and within the Australian professional engineering work force. Similar trends are identified in other countries, which lead to further predictions of future drastic reductions in immigration of engineers to Australia. The overall conclusion is a rapidly developing scarcity of professional engineers in Australia and a very significant reduction in the growth rate of the professional engineering labor force. Similar trends are indicated in other countries including the United States. Some remedial human resource management strategies for Australia are identified.