How well do truck drivers sleep in cabin sleeper berths?

The aim of this study was to evaluate the sleep obtained by livestock transport truck drivers while resting in truck sleeper berths during long-haul commercial operations. Operations were carried out in the very remote regions of Australia. The sample comprised of 32 drivers who wore wrist activity monitors and reported bed-times for a two-week period. Drivers had a mean (±standard deviation) age of 35.41 (± 9.78) years and had worked as truck drivers for 13.83 (± 9.11) years. On average, they obtained 6.07 (± 1.18) hours of sleep/24-h period. The majority of sleep occurred at night, but drivers occasionally supplemented their main sleep with a daytime nap. Consistent with operational demands, drivers were most likely to sleep in cabin sleeper berths (n = 394, 77%). Only a small proportion of sleeps were sampled at home (n = 63, 12%) or at truck depots (n = 56, 11%). Mixed-model ANOVA revealed that while earlier bed-times at home yielded more sleep, there were only marginal differences in sleep quality across location. No intrinsic safety concerns associated with the use of sleeper berths were identified across consecutive days of long-haul transport operations.     

Pilot mental workload: how well do pilots really perform?

The purpose of this study was to investigate the effects of increasing mental demands on various aspects of aircrew performance. In particular, the robustness of the prioritization and allocation hierarchy of aviate-navigate-communicate was examined, a hierarchy commonly used within the aviation industry. A total of 42 trainee pilots were divided into three workload groups (low, medium, high) to complete a desktop, computer-based exercise that simulated combinations of generic flight deck activities: flight control manipulation, rule-based actions and higher level cognitive processing, in addition to Air Traffic Control instructions that varied in length from one chunk of auditory information to seven chunks. It was found that as mental workload and auditory input increased, participants experienced considerable difficulty in carrying out the primary manipulation task. A similar decline in prioritization was also observed. Moreover, when pilots were under a high mental workload their ability to comprehend more than two chunks of auditory data deteriorated rapidly.     

Pilot mental workload: how well do pilots really perform?

The purpose of this study was to investigate the effects of increasing mental demands on various aspects of aircrew performance. In particular, the robustness of the prioritization and allocation hierarchy of aviate–navigate–communicate was examined, a hierarchy commonly used within the aviation industry. A total of 42 trainee pilots were divided into three workload groups (low, medium, high) to complete a desktop, computer-based exercise that simulated combinations of generic flight deck activities: flight control manipulation, rule-based actions and higher level cognitive processing, in addition to Air Traffic Control instructions that varied in length from one chunk of auditory information to seven chunks. It was found that as mental workload and auditory input increased, participants experienced considerable difficulty in carrying out the primary manipulation task. A similar decline in prioritization was also observed. Moreover, when pilots were under a high mental workload their ability to comprehend more than two chunks of auditory data deteriorated rapidly.     

How well do shopbots represent online markets? A study of shopbots’ vendor coverage strategy

Consumers often use shopbots to search for information when making purchase decisions in Internet markets. Although they have varying sensitivity to shopbot bias, consumers generally prefer accurate market representation. However, in choosing the accuracy of market representation, shopbots must balance the desires of consumers with the costs of providing their services and with the desires of the vendors, who are often the largest source of their revenue. In this paper, we study how accurately shopbots represent a market and analyze the strategies shopbots adopt to achieve market representativeness. We theoretically identify two important drivers in shopbot vendor coverage strategy – how many vendors it covers (shopbot size) and which vendors it covers (shopbot affiliation) – and analytically show how the drivers affect shopbot market representativeness. We report the results of a large-scale study in which we collected 2.2 million vendor price listings from eight shopbots and develop metrics for measuring shopbot size, shopbot affiliation, and shopbot market representativeness. We found that (1) shopbots do not represent markets equally well; (2) size drives a shopbot's market representativeness positively whereas affiliation drives a shopbot's market representativeness negatively; (3) shopbots follow differnet vendor representative strategies to pursue market representativeness.     

How do usability professionals construe usability?

Usability professionals have attained a specialist role in systems-development projects. This study analyses usability professionals’ operational understanding of usability by eliciting the constructs they employ in their thinking about system use. We approach usability broadly and without a priori distinguishing it from user experience. On the basis of repertory-grid interviews with 24 Chinese, Danish, and Indian usability professionals we find that they make use of more utilitarian than experiential, i.e. user-experience related, constructs. This indicates that goal-related performance is central to their thinking about usability, whereas they have less elaborate sets of experiential constructs. The usability professionals mostly construe usability at an individual level, rather than at organizational and environmental levels. The few exceptions include effectiveness constructs, which are evenly spread across all three levels, and relational constructs, which are phrased in terms of social context. Considerations about users’ cognitive activities appear more central to the usability professionals than conventional human-factors knowledge about users’ sensorial abilities. The usability professionals’ constructs, particularly their experiential constructs, go considerably beyond ISO 9241 usability, indicating a discrepancy between this definition of usability and the thinking of the professionals concerned with delivering usability. Finally, usability is construed rather similarly across the three nationalities of usability professionals.     

How do open source communities blog?

We report on an exploratory study, which aims at understanding how software communities use blogs compared to conventional development infrastructures. We analyzed the behavior of 1,100 bloggers in four large open source communities, distinguishing between committing bloggers and other community members. We observed that these communities intensively use blogs with one new entry every 8 h. A blog entry includes 14 times more words than a commit message. When analyzing the content of the blogs, we found that committers and others bloggers write about similar topics. Most popular topics in committers’ blogs represent high-level concepts such as features and domain concepts, while source code related topics are discussed in 15% of their posts. Other community members frequently write about community events and conferences as well as configuration and deployment topics. We found that the blogging peak period is usually after the software is released. Moreover, committers are more likely to blog after corrective engineering than after forward engineering and re-engineering activities. Our findings call for a hypothesis-driven research to (a) further understand the role of social media in dissolving the collaboration boundaries between developers and other stakeholders and (b) integrate social media into development processes and tools.     

How do we evaluate artificial immune systems?

The field of Artificial Immune Systems (AIS) concerns the study and development of computationally interesting abstractions of the immune system. This survey tracks the development of AIS since its inception, and then attempts to make an assessment of its usefulness, defined in terms of 'distinctiveness' and 'effectiveness.' In this paper, the standard types of AIS are examined--Negative Selection, Clonal Selection and Immune Networks--as well as a new breed of AIS, based on the immunological 'danger theory.' The paper concludes that all types of AIS largely satisfy the criteria outlined for being useful, but only two types of AIS satisfy both criteria with any certainty.     

How do interactive tabletop systems influence collaboration?

This paper examines some aspects of the usefulness of interactive tabletop systems, if and how these impact collaboration. We chose creative problem solving such as brainstorming as an application framework to test several collaborative media: the use of pen-and-paper tools, the “around-the-table” form factor, the digital tabletop interface, the attractiveness of interaction styles. Eighty subjects in total (20 groups of four members) participated in the experiments. The evaluation criteria were task performance, collaboration patterns (especially equity of contributions), and users’ subjective experience. The “around-the-table” form factor, which is hypothesized to promote social comparison, increased performance and improved collaboration through an increase of equity. Moreover, the attractiveness of the tabletop device improved subjective experience and increased motivation to engage in the task. However, designing attractiveness seems a highly challenging issue, since overly attractive interfaces may distract users from the task.     

Can pilots time-share better than non-pilots?

Time-sharing performance of a group of pilots was compared with that of a group of college students. In a secondary task paradigm, both groups were required to perform five dual tasks with various degrees of structural similarity. A higher degree of task interference was observed for the structurally more similar task pairs. The data were consistent with the results from previous research and support the concept of multiple resources. Although the pilots appeared to be more efficient in one of the dual task conditions, evidence for a general difference in time-sharing ability between the students and the pilots was not compelling. It was concluded that the degree to which time-sharing performance is structure dependent is not easily alterable by training. The results suggested that laboratory findings on the structural determinants of time-sharing efficiency are generalisable to operational environments.     

How do Attitudes Toward Globalization Influence Human Functioning?

ABSTRACT

This study shows the results of the research into the relationships between attitudes toward globalization (accepting, critical, fearful) and psychological factors: identity styles, attitudes toward the Internet, and the quality of friendship. The survey conducted among Polish adolescents and young adults revealed that attitudes toward globalization had a stronger influence on psychological functioning for young adults than for adolescents. The results may help to understand social acceptance factors or disapproval of technological and globalizational changes.     

How and why do student teachers use ICT?

This paper examines how and why student teachers made use of information and communication technology (ICT) during a 1‐year initial teacher education programme from 2008 to 2009. This is a mixed methods study involving a survey (N = 340) of the entire cohort and a series of semi‐structured interviews with a sample of student teachers within the cohort (N = 21). The study explored several themes, including the nature of student teachers' use of ICT; variation in the use of ICT; support for, and constraints on, using ICT; attitudes to ICT and to teaching and learning more generally. It was found that nearly all teachers were receptive to using ICT – more so than their in‐service counterparts – and made frequent use of it during their placement (internship) experience. The Interactive Whiteboard (IWB) was central to nearly all student teachers' use of ICT, in good part, because it was already used by their mentors and was widely accessible. Student teachers' use of ICT was categorized in three levels. Routine users focused mostly on the use of the IWB for whole class teaching; extended users gave greater opportunities for pupils to use ICT for themselves; innovative student teachers used ICT in a greater range of contexts and made more effort to overcome barriers such as access. ICT use was seen as emerging from a mix of factors: chiefly student teachers' access to ICT; their feeling of ‘self‐efficacy’ when using ICT; and their belief that ICT had a positive impact on learning – in particular, the impact on pupils' behavioural and affective engagement. Factors which influenced ICT use included mentoring, training and support. Limitations on student teachers' use of ICT are explored and it is suggested that new teachers need to be supported in developing a more discerning use as they begin their teaching careers.     

How well does test case prioritization integrate with statistical fault localization?

ContextEffective test case prioritization shortens the time to detect failures, and yet the use of fewer test cases may compromise the effectiveness of subsequent fault localization.ObjectiveThe paper aims at finding whether several previously identified effectiveness factors of test case prioritization techniques, namely strategy, coverage granularity, and time cost, have observable consequences on the effectiveness of statistical fault localization techniques.MethodThis paper uses a controlled experiment to examine these factors. The experiment includes 16 test case prioritization techniques and four statistical fault localization techniques using the Siemens suite of programs as well as grep, gzip, sed, and flex as subjects. The experiment studies the effects of the percentage of code examined to locate faults from these benchmark subjects after a given number of failures have been observed.ResultsWe find that if testers have a budgetary concern on the number of test cases for regression testing, the use of test case prioritization can save up to 40% of test case executions for commit builds without significantly affecting the effectiveness of fault localization. A statistical fault localization technique using a smaller fraction of a prioritized test suite is found to compromise its effectiveness seriously. Despite the presence of some variations, the inclusion of more failed test cases will generally improve the fault localization effectiveness during the integration process. Interestingly, during the variation periods, adding more failed test cases actually deteriorates the fault localization effectiveness. In terms of strategies, Random is found to be the most effective, followed by the ART and Additional strategies, while the Total strategy is the least effective. We do not observe sufficient empirical evidence to conclude that using different coverage granularity levels have different overall effects.ConclusionThe paper empirically identifies that strategy and time–cost of test case prioritization techniques are key factors affecting the effectiveness of statistical fault localization, while coverage granularity is not a significant factor. It also identifies a mid-range deterioration in fault localization effectiveness when adding more test cases to facilitate debugging.     

How do we fit underground coal mining work boots?

Abstract

Acceptable footwear fit, particularly width, is subjective and vaguely quantified. Proper shoe fit is important because it affects both comfort and the potential to prevent injury. Although mismatches between the feet of underground coal miners and their internal boot dimensions are known, no research has been undertaken to determine the impact of these mismatches on worker perceptions of fit, comfort and pain. This study aimed to quantitatively assess mining work boot fit relative to underground coal miners’ subjectively rated work boot fit and comfort, reported foot problems, lower limb pain and lower back pain in order to develop evidence-based work boot fit recommendations. Traditional footwear fitting methods based predominantly on foot length are insufficient for underground coal mining-specific footwear. Instead, fit at the heel, instep and forefoot must be considered when fitting underground coal mining work boots, in conjunction with the traditional length measurement.Practitioner summary: Underground coal miners report their work boots fit but are uncomfortable. This study assessed actual fit relative to perceived fit, comfort, foot problems, lower limb pain and lower back pain of 197 miners. Fit at the heel, instep and forefoot must be considered when fitting mining work boots.     

How do interruptions affect user contributions on social commerce?

Social commerce is an extension of e‐commerce, in which social media is leveraged to promote user contributions. Our study asks how interruptions in relation to interface design influence two types of user contributions: creating shared content and appreciating others' content. We use two interface designs, pagination and infinite scrolling, to manipulate the extent of interruptions to social commerce users. On the basis of the capacity theory of attention, we develop five hypotheses. We empirically test our model using a lab experiment and a field study to show that interruptions reduce users' content appreciation but increase their content creation and that user characteristics moderate these effects. The theoretical and practical contributions of our study are discussed.     

How do designers represent to themselves the users' needs?

This paper reports on an ergonomic study carried out during the design of a cutting machine-tool for the composite material in carbody parts casting. During this design process, the users’ needs were inferred by the designers on the basis of their own mental representations of the use of the new device. These representations of the users’ needs, correct or false, play a decisive role in the choice of a solution. The aim of the study is to identify their particularity. Analyzing the design meetings, we have highlighted that users are considered either as subsystems or basic design principles or elements of an imagined scenario. We have shown that these representations are linked to the types of meetings held during the design process. Accordingly, a diversification of the types of meetings should be promoted by the project leader, so that designers extend their points of view of the operators.     

How do employees prioritise when they schedule their own shifts?

We investigated how employees prioritised when they scheduled their own shifts and whether priorities depended on age, gender, educational level, cohabitation and health status. We used cross-sectional questionnaire data from the follow-up survey of an intervention study investigating the effect of self-scheduling (n = 317). Intervention group participants were asked about their priorities when scheduling their own shifts succeeded by 17 items covering family/private life, economy, job content, health and sleep. At least half of the participants reported that they were giving high priority to their family life, having consecutive time off, leisure-time activities, rest between shifts, sleep, regularity of their everyday life, health and that the work schedule balanced. Thus, employees consider both their own and the workplace's needs when they have the opportunity to schedule their own shifts. Age, gender, cohabitation and health status were all significantly associated with at least one of these priorities.

Practitioner Summary: Intervention studies report limited health effects of self-scheduling. Therefore, we investigated to what extent employees prioritise their health and recuperation when scheduling their own shifts. We found that employees not only consider both their health and family but also the workplace's needs when they schedule their own shifts.     

How do colors influence the haptic perception of textured surfaces?

Multimodality is considered a promising approach for universal access, and haptic interaction has the potential to constitute an added dimension to multimodal interfaces. This paper describes the influence of colors on the haptic perception of textured surfaces, based on 8 experiments. Our results show that (1) colors do have an influence on haptic perception, but they do not make the perception error rate higher than when no color is used; (2) up to 6 different types of colors can be used in haptic interfaces without worsening the haptic perception; (3) yellow has an error rate that is statistically significantly lower than that of 3 other color conditions, and can be used without worsening the haptic perception; (4) our finding of two special orders for haptic perception demonstrates that human haptic perception is very sensitive to continuously increasing or decreasing changes of roughness, but has difficulty discerning randomly changed roughness.     

Fighter pilots’ heart rate,heart rate variation and performance during instrument approaches

Fighter pilots’ heart rate (HR), heart rate variation (HRV) and performance during instrument approaches were examined. The subjects were required to fly instrument approaches in a high-fidelity simulator under various levels of task demand. The task demand was manipulated by increasing the load on the subjects by reducing the range at which they commenced the approach. HR and the time domain components of HRV were used as measures of pilot mental workload (PMWL). The findings of this study indicate that HR and HRV are sensitive to varying task demands. HR and HRV were able to distinguish the level of PMWL after which the subjects were no longer able to cope with the increasing task demands and their instrument landing system performance fell to a sub-standard level. The major finding was the HR/HRV’s ability to differentiate the sub-standard performance approaches from the high-performance approaches.

Practitioner Summary:

This paper examined if HR and HRV were sensitive to varying task demands in a fighter aviation environment and if these measures were related to variations in pilot’s performance.     

How do architecture patterns and tactics interact? A model and annotation

Software architecture designers inevitably work with both architecture patterns and tactics. Architecture patterns describe the high-level structure and behavior of software systems as the solution to multiple system requirements, whereas tactics are design decisions that improve individual quality attribute concerns. Tactics that are implemented in existing architectures can have significant impact on the architecture patterns in the system. Similarly, tactics that are selected during initial architecture design significantly impact the architecture of the system to be designed: which patterns to use, and how they must be changed to accommodate the tactics. However, little is understood about how patterns and tactics interact. In this paper, we develop a model for the interaction of patterns and tactics that enables software architects to annotate architecture diagrams with information about the tactics used and their impact on the overall structure. This model is based on our in-depth analysis of the types of interactions involved, and we show several examples of how the model can be used to annotate different kinds of architecture diagrams. We illustrate the model and annotation by showing examples taken from real systems, and describe how the annotation was used in architecture reviews. Tactics and patterns are known architectural concepts; this work provides more specific and in-depth understanding of how they interact. Its other key contribution is that it explores the larger problem of understanding the relation between strategic decisions and how they need to be tailored in light of more tactical decisions.     

How do Simple Rules `Fit to Reality' in a Complex World?

The theory of fast and frugal heuristics, developed in a new book called Simple Heuristics that make Us Smart (Gigerenzer, Todd, and the ABC Research Group, in press), includes two requirements for rational decision making. One is that decision rules are bounded in their rationality –- that rules are frugal in what they take into account, and therefore fast in their operation. The second is that the rules are ecologically adapted to the environment, which means that they `fit to reality.' The main purpose of this article is to apply these ideas to learning rules–-methods for constructing, selecting, or evaluating competing hypotheses in science, and to the methodology of machine learning, of which connectionist learning is a special case. The bad news is that ecological validity is particularly difficult to implement and difficult to understand. The good news is that it builds an important bridge from normative psychology and machine learning to recent work in the philosophy of science, which considers predictive accuracy to be a primary goal of science.