ABSTRACT
Road collision types repeat themselves, especially in low- and middle-income countries (LMICs), where countermeasures are often improvised and implemented with little planning. At the Shahbag intersection in Dhaka, Bangladesh, speed bumps were quickly constructed at the exit of the intersection as an improvised road safety measure following the occurrence of a fatal collision, which eventually contributed to another collision between a truck and a car. The events influencing the improvisation decision, and that action's consequences, have been analysed using the Impromap methodology, a variation of the Accimap approach that focusses specifically on improvisation. The applicability of the Impromap as a systems-based approach to the road safety domain is assessed using the predictions described in Rasmussen's risk management framework, and corresponding countermeasures are proposed. The analysis shows that improvisation in the road safety domain is undesirable irrespective of the economic setting as it is likely to eventually contribute to secondary collisions.Practitioner summary: In this paper, the events influencing the improvisation decision following a road crash, and that action's consequences, have been analysed using the Impromap methodology. The applicability of Impromap as a systems-based approach in road safety domain is assessed using the Rasmussen's risk management framework-based predictions, and corresponding countermeasures are proposed.
Subject(s)
Accidents, Traffic , Motor Vehicles , Humans , Accidents, Traffic/prevention & control , Bangladesh , Risk Management , Systems Analysis , SafetyABSTRACT
We prepare mixtures of ultracold CaF molecules and Rb atoms in a magnetic trap and study their inelastic collisions. When the atoms are prepared in the spin-stretched state and the molecules in the spin-stretched component of the first rotationally excited state, they collide inelastically with a rate coefficient k_{2}=(6.6±1.5)×10^{-11} cm^{3}/s at temperatures near 100 µK. We attribute this to rotation-changing collisions. When the molecules are in the ground rotational state we see no inelastic loss and set an upper bound on the spin-relaxation rate coefficient of k_{2}<5.8×10^{-12} cm^{3}/s with 95% confidence. We compare these measurements to the results of a single-channel loss model based on quantum defect theory. The comparison suggests a short-range loss parameter close to unity for rotationally excited molecules, but below 0.04 for molecules in the rotational ground state.
ABSTRACT
Public aquariums and similar institutions often use video as a method to monitor the behavior, health, and status of aquatic organisms in their environments. These video footages take up a sizeable amount of space and require the use of autoencoders to reduce their file size for efficient storage. The autoencoder neural network is an emerging technique which uses the extracted latent space from an input source to reduce the image size for storage, and then reconstructs the source within an acceptable loss range for use. To meet an aquarium's practical needs, the autoencoder must have easily maintainable codes, low power consumption, be easily adoptable, and not require a substantial amount of memory use or processing power. Conventional configurations of autoencoders often provide results that perform beyond an aquarium's needs at the cost of being too complex for their architecture to handle, while few take low-contrast sources into consideration. Thus, in this instance, "keeping it simple" would be the ideal approach to the autoencoder's model design. This paper proposes a practical approach catered to an aquarium's specific needs through the configuration of autoencoder parameters. It first explores the differences between the two of the most widely applied autoencoder approaches, Multilayer Perceptron (MLP) and Convolution Neural Networks (CNN), to identify the most appropriate approach. The paper concludes that while both approaches (with proper configurations and image preprocessing) can reduce the dimensionality and reduce visual noise of the low-contrast images gathered from aquatic video footage, the CNN approach is more suitable for an aquarium's architecture. As an unexpected finding of the experiments conducted, the paper also discovered that by manipulating the formula for the MLP approach, the autoencoder could generate a denoised differential image that contains sharper and more desirable visual information to an aquarium's operation. Lastly, the paper has found that proper image preprocessing prior to the application of the autoencoder led to better model convergence and prediction results, as demonstrated both visually and numerically in the experiment. The paper concludes that by combining the denoising effect of MLP, CNN's ability to manage memory consumption, and proper image preprocessing, the specific practical needs of an aquarium can be adeptly fulfilled.
Subject(s)
Neural Networks, Computer , HumansABSTRACT
This study takes a qualitative approach to exploring the experiences (and differences therein) of individuals using either their car, bicycle, or motorcycle to navigate a â¼10.5 km urban route in a provincial UK city, with the aim of contributing to our understanding of the needs and requirements of different road users. Forty-six individuals provided concurrent verbal reports, using the 'think aloud' method, whilst using their vehicle to navigate the test route, the transcripts of which were subjected to a theory-agnostic, inductive, thematic analysis. A number of group differences were observed, revealing (among other factors) the importance of road surface quality to cyclists, the focus on vigilant observation in motorcyclists, and the heightened emotionality experienced by both two-wheeled groups, particularly those on bicycles. This affective component has, as yet, been under-explored in the academic domain and under-utilised in road transport policy and strategy; this is discussed, with attention drawn to the cyclists' greater tendency to make negatively valenced value judgements. Results are also discussed in terms of the potential to improve road users' experiences, foster inter-group empathy and understanding, and encourage a shift in mobility towards more sustainable modes.
ABSTRACT
Road safety strategies adopted worldwide have made significant progress in reducing road trauma, but have stagnated more recently. The situation in low- and middle-income countries is even worse with no significant decrease in fatality rates. Safety researchers have argued that adopting sociotechnical systems approach is necessary to make significant advancements and improvements. The aim of this study was to develop a control structure model of the Bangladesh road safety system by identifying the actors and organisations involved across the system. Expert stakeholders were identified and interviewed, and relevant information was gathered in order to generate the Systems Theoretic Accident Model and Process control structure model. Throughout the analysis of this model, differences in the control and feedback mechanisms of the system were identified, and road safety intervention recommendations were made. Future research should also predict potential risks within the system and propose proactive and preventative countermeasures. Practitioner summary: In this article, a Systems Theoretic Accident Model and Process control structure model of the Bangladesh road safety system is developed, and the involved actors are identified. Based on interviews and workshops with expert stakeholders, differences in the controls and feedback mechanisms in the system were identified, and road safety intervention recommendations were made. Abbreviations: BUET: Bangladesh University of Engineering and Technology.
Subject(s)
Accidents, Traffic , Income , Accidents, Traffic/prevention & control , Humans , SafetyABSTRACT
Typical methods to holographically encode arbitrary wavefronts assume the hologram medium only applies either phase shifts or amplitude attenuation to the wavefront. In many cases, phase cannot be introduced to the wavefront without also affecting the amplitude. Here we show how to encode an arbitrary wavefront into an off-axis transmission hologram that returns the exact desired arbitrary wavefunction in a diffracted beam for phase-only, amplitude-only, or mixed phase and amplitude holograms with any periodic groove profile. We apply this to design thin holograms for electrons in a TEM, but our results are generally applicable to light and X-ray optics. We employ a phase reconstruction from a series of focal plane images to qualitatively show the accuracy of this method to impart the expected amplitude and phase to a specific diffraction order.
ABSTRACT
Seemingly erratic pedestrian crossing has become a major source of vehicle-pedestrian collisions on highways in Bangladesh, and across other low- and middle-income countries (LMICs). In this article, we approach the challenge from a sociotechnical systems perspective by using the Accimap method to analyse a pair of time-separated yet interconnected road traffic collisions. The first event involved a truck colliding with a road divider; in the second, fatal incident, a bus hit a university student. The traditional-style investigation conducted immediately after the collision apportioned blame to end users, that is, drivers and pedestrian; however, application of sociotechnical systems thinking revealed the contribution from lack of emergency response and enforcement among many other important factors. Results and recommendations are discussed in terms of reducing the chance and severity of such collisions across LMICs, and in terms of the need to look beyond the end-user, a focus that remains dominant in such settings. Practitioner summary: This paper applies sociotechnical systems thinking to pedestrian safety in Bangladesh by analysing two inter-connected road traffic collisions using a single Accimap. The findings emphasise the importance of implementing road safety interventions that target all system levels, and draw attention to the importance of post-collision response in low-income settings. Abbreviation: BUET: Bangladesh University of Engineering and Technology.
Subject(s)
Accidents, Traffic/prevention & control , Automobile Driving , Emergency Medical Dispatch , Law Enforcement , Pedestrians , Safety , Bangladesh , Humans , Poverty , Risk FactorsABSTRACT
As genomic sequencing expands, so does our knowledge of the link between genetic variation and disease. Deeper catalogs of variant frequencies improve identification of benign variants, while sequencing affected individuals reveals disease-associated variation. Accumulation of human genetic data thus makes reanalysis a means to maximize the benefits of clinical sequencing. We implemented pipelines to systematically reassess sequencing data from 494 individuals with developmental disability. Reanalysis yielded pathogenic or likely pathogenic (P/LP) variants that were not initially reported in 23 individuals, 6 described here, comprising a 16% increase in P/LP yield. We also downgraded 3 LP and 6 variants of uncertain significance (VUS) due to updated population frequency data. The likelihood of identifying a new P/LP variant increased over time, as ~22% of individuals who did not receive a P/LP variant at their original analysis subsequently did after 3 years. We show here that reanalysis and data sharing increase the diagnostic yield and accuracy of clinical sequencing.
Subject(s)
Developmental Disabilities/diagnosis , Developmental Disabilities/genetics , Genetic Variation , Genomics , Intellectual Disability/diagnosis , Intellectual Disability/genetics , Alleles , DNA Copy Number Variations , Gene Frequency , Genetic Testing , Genomics/methods , Genotype , Humans , Polymorphism, Single Nucleotide , Exome Sequencing , Whole Genome SequencingABSTRACT
Many interesting but practically intractable problems can be reduced to that of finding the ground state of a system of interacting spins; however, finding such a ground state remains computationally difficult. It is believed that the ground state of some naturally occurring spin systems can be effectively attained through a process called quantum annealing. If it could be harnessed, quantum annealing might improve on known methods for solving certain types of problem. However, physical investigation of quantum annealing has been largely confined to microscopic spins in condensed-matter systems. Here we use quantum annealing to find the ground state of an artificial Ising spin system comprising an array of eight superconducting flux quantum bits with programmable spin-spin couplings. We observe a clear signature of quantum annealing, distinguishable from classical thermal annealing through the temperature dependence of the time at which the system dynamics freezes. Our implementation can be configured in situ to realize a wide variety of different spin networks, each of which can be monitored as it moves towards a low-energy configuration. This programmable artificial spin network bridges the gap between the theoretical study of ideal isolated spin networks and the experimental investigation of bulk magnetic samples. Moreover, with an increased number of spins, such a system may provide a practical physical means to implement a quantum algorithm, possibly allowing more-effective approaches to solving certain classes of hard combinatorial optimization problems.
ABSTRACT
An online survey of 321 respondents revealed that the majority of people are aware of eco-driving and have a positive attitude towards it. Although the types of eco-driving tips offered by respondents, and their potential effect on fuel consumption, were in line with those found in the popular and academic literature, knowledge of specific fuel saving behaviours was generally low. Relationships were found between environmental attitudes and knowledge of, and propensity to perform eco-driving behaviours; however, these relationships were weak, indicating that neither pro-environmental attitudes nor knowledge of eco-driving behaviours is strongly indicative of actual eco-driving performance. Males were found to be more knowledgeable of the means for driving in a fuel-efficient manner than females; however, no effect was found for either age or level of general education. Results are discussed in terms of the challenges and opportunities for encouraging eco-driving, and the necessity for both governmental and industry involvement. Practitioner Summary: To successfully encourage the uptake of eco-driving (e.g. through policy, training and feedback) it is first necessary to understand how the general public perceives it, and what they already know of it. This survey study addresses this by looking at relationships between environmental attitudes and knowledge, and specific eco-driving measures.
Subject(s)
Automobile Driving/psychology , Conservation of Energy Resources , Health Knowledge, Attitudes, Practice , Adolescent , Adult , Aged , Female , Fossil Fuels , Humans , Male , Middle Aged , Surveys and Questionnaires , Young AdultABSTRACT
This paper provides a decision ladder analysis of eco-driving, and a discussion of the resultant models in terms of the skills, rules and knowledge taxonomy of human behaviour and how this can inform the design of an in-vehicle, eco-driving support system. In order to understand the types of behaviours that characterise fuel-efficient driving, a review was conducted of the academic literature and of more publicly available resources, such as governmental, car manufacturers' and specific eco-driving organisations' websites. The review identified four largely distinct driving activities that play a central role in the use of fuel in the private road vehicle. A focus group involving four researchers in the transport ergonomics field, followed by a series of five interviews with eco-driving experts, served to validate, supplement and further specify the models. Practitioner Summary: This paper presents a decision ladder analysis of eco-driving. A four-member focus group and five interviews with eco-driving experts were conducted; the resultant models are discussed in terms of supporting fuel-efficient driving behaviours in the novice eco-driver through their potential to inform the design of an in-vehicle eco-driving support system.
Subject(s)
Automobile Driving , Decision Support Techniques , Vehicle Emissions/prevention & control , Adult , Aged , Ergonomics , Focus Groups , Humans , Male , Middle Aged , Models, TheoreticalABSTRACT
Environmental concerns show that transport is responsible for almost a quarter of all greenhouse gas emissions, and it is also the fastest growing sector. Modal shift towards public transport could help slow down, or even reverse, this trend. There appear to be a number of constraints that are preventing this from happening. This paper explores the constraints to modal shift to rail transport from the perspective of cognitive work analysis, specifically the abstraction hierarchy, the contextual activity template and social organisational and cooperation analyses. Whilst these analyses may not present any new barriers, they do show how the constraints are interlinked in an explicit manner. These interrelations are important for two reasons. First, in consideration of constraint removal, one must anticipate the likely effects on the remainder of the system. Second, by linking functions and situations, new concepts of travel may be identified and explored. PRACTITIONER SUMMARY: The purpose of this study was to use a semi-structured approach to identifying constraints to modal shift from a variety of perspectives. It is argued that cognitive work analysis offers a new way of thinking about the modal shift problem and helps to generate new insights into potential solutions.
Subject(s)
Automobiles , Choice Behavior , Railroads , Safety , Air Pollution/prevention & control , Automobiles/economics , Humans , Models, Theoretical , Perception , Railroads/economics , Time FactorsABSTRACT
Greater uptake of active transport has been argued as necessary for the transport system to achieve relevant sustainability and public health goals; however, the research tools used to investigate behaviour when using these modes are far less well-developed than those used to investigate driving behaviour. This study takes two self-report behavioural measures, the Walking Behaviour Questionnaire (WBQ) and the Cycling Behaviour Questionnaire (WBQ), and pilots them in the UK. Exploratory and confirmatory factor analyses with data from 428 respondents revealed factor structures different to those described in the limited number of previous studies that used the CBQ and WBQ. Across both questionnaires, scales measuring intentional behaviour differed from original descriptions to a greater extent than did the scale concerning unintentional attention or memory errors. In addition to a validation exercise, this research explored the relationships between variables, finding a correlation between the reported performance of unintentional errors when walking and cycling. Looking in more detail at cycling behaviours, we found that those who rated themselves as more proficient cyclists also reported performing fewer unintentional cycling errors. Results also showed self-reported helmet use to bear little to no relationship with other self-reported cycling behaviours or self-rated cycling proficiency. Finally, using structural equation modelling, we demonstrated that responses to the CBQ add very little (over and above age, gender, and exposure to the road environment) to the explanation of self-reported past collision involvement. In total, only 7% of the variation in past collision involvement was explained by the included variables. We urge caution when using self-report behavioural measures that have not been validated in the context of intended use, and the importance of using such measures in combination with other approaches rather than in isolation when trying to develop an understanding of overall system performance.
Subject(s)
Accidents, Traffic , Bicycling , Humans , Surveys and Questionnaires , United Kingdom , WalkingABSTRACT
Research into road safety has evolved from individual level component analysis to a much broader, systemic approach that acknowledges the fusion of 'socio' and 'technical' system elements. Over the past four decades, Professor Neville Stanton has contributed to over 179 journal articles, book chapters and conference papers in the field of road safety. The journey from 'thinking humans' to 'systems thinking' is demonstrated in this paper through the novel application of the Risk Management Framework (RMF) to the categorisation of research activities. A systematic review of Neville's contributions to the field of road safety demonstrates that over the years, his research activities have evolved from investigating single technological or human performance aspects in isolation (e.g., in-vehicle information design and workload) through to the holistic analysis of much broader systems (e.g., investigating road safety as a whole). Importantly, this evolution goes hand in hand with a change in the focus and emphasis of recommendations for improvements to safety. Going forward, Neville has helped pave the way for fundamental changes and improvements to be made to road safety systems around the world.
Subject(s)
Accidents, Traffic , Information Systems , Accidents, Traffic/prevention & control , Humans , SafetyABSTRACT
Recently, ergonomics and safety researchers have turned their attention towards applying combinations of sociotechnical methods rather than using single methods in isolation. In the current research, a mixed-method approach combining two systems-based methods, Accimaps and the Systems Theoretic Accident Model and Process - Causal Analysis using Systems Theory (STAMP-CAST), and one cognitive approach, the Perceptual Cycle Model (PCM), were employed in analysing a rail-level crossing incident in Bangladesh. Each method was applied individually to investigate the collision, and interventions were proposed corresponding to incident events at different risk management framework levels. The three methods provided different perspectives of the whole picture, together identifying an array of contributory factors. The complementary nature of these methods aided in proposing a comprehensive set of safety recommendations, thereby demonstrating the benefit of a mixed-method approach for collision investigation in low-income settings.
Subject(s)
Systems Analysis , Systems Theory , Accidents , Causality , Ergonomics , HumansABSTRACT
Road safety has become a worldwide public health concern. Although many factors contribute to collisions, pedestrian behaviors can strongly influence road safety outcomes. This paper presents results of a survey investigating the effects of age, gender, attitudes towards road safety, fatalistic beliefs and risk perceptions on self-reported pedestrian behaviors in a Chinese example. The study was carried out on 543 participants (229 men and 314 women) from 20 provinces across China. Pedestrian behaviors were assessed by four factors: errors, violations, aggressions, and lapses. Younger people reported performing riskier pedestrian behaviors compared to older people. Gender was not an influential factor. Of the factors explored, attitudes towards road safety explained the most amount of variance in self-reported behaviors. Significant additional variance in risky pedestrian behaviors was explained by the addition of fatalistic beliefs. The differences among the effects, and the implications for road safety intervention design, are discussed. In particular, traffic managers can provide road safety education and related training activities to influence pedestrian behaviors positively.
Subject(s)
Pedestrians , Accidents, Traffic , Aged , Aged, 80 and over , Attitude , China , Female , Humans , Male , Perception , Safety , WalkingABSTRACT
In Bangladesh, pedestrians remain the most neglected road user group in terms of research and safety measures, even though they are involved in nearly 50% of all fatal collisions. In the Dhaka metropolitan area, this statistic rises to around 65%. To reduce the recurrence of such collisions, it is necessary to understand the underlying thought processes of pedestrians, and how pedestrians interact with different road users, particularly when crossing the road. This study contributes to knowledge through the analysis of verbal data from 46 pedestrians, framed in terms of the Perceptual Cycle Model, where cognitive processes are described in terms of three categories: schema (mental templates), action (doing things), and world (environmental information). Concurrent verbal reports were provided by participants while they negotiated a busy area of mixed traffic in the centre of Dhaka city. The analysis revealed some of the factors that affected decision-making (for road crossing behaviour) at the different road sections. Many external factors (e.g., street sellers, rubbish blocking the path, lack of shade and poor pavement condition) prevented the pavement from being used and contributed to riskier road crossing behaviour. Some safety implications and related recommendations are presented.
ABSTRACT
This paper reports on an exploratory investigation of the influence of five different fatalistic belief constructs (divine control, luck, helplessness, internality, and general fatalism) on three classes of self-reported pedestrian behaviours (memory and attention errors, rule violations, and aggressive behaviours) and on respondents' general attitudes to road safety, and how relationships between constructs differ across countries. A survey of over 3400 respondents across Bangladesh, China, Kenya, Thailand, the UK, and Vietnam revealed a similar pattern for most of the relationships assessed, in most countries; those who reported higher fatalistic beliefs or more external attributions of causality also reported performing riskier pedestrian behaviours and holding more dangerous attitudes to road safety. The strengths of relationships between constructs did, however, differ by country, behaviour type, and aspect of fatalism. One particularly notable country difference was that in Bangladesh and, to a lesser extent, in Kenya, a stronger belief in divine influence over one's life was associated with safer attitudes and behaviours, whereas where significant relationships existed in the other countries the opposite was true. In some cases, the effect of fatalistic beliefs on self-reported behaviours was mediated through attitudes, in other cases the effect was direct. Results are discussed in terms of the need to consider the effect of locus of control and attributions of causality on attitudes and behaviours, and the need to understand the differences between countries therein.
Subject(s)
Attitude , Pedestrians/psychology , Spirituality , Accidents, Traffic/mortality , Adolescent , Adult , Cross-Cultural Comparison , Female , Humans , Male , Middle Aged , Pedestrians/statistics & numerical data , Risk-Taking , Surveys and Questionnaires , Young AdultABSTRACT
Images of the (001) planes of muscovite were observed by electron microscopy after embedment of clay-size flakes in epoxy resin and sectioning by ultramicrotome. Dislocation or growth planes were indicated. Incomplete exchange of potassium for barium produced zones with 20-angstrom periodicity, suggesting regular interstratification.
ABSTRACT
Some species of reptiles regularly ingest soil in the wild. Therefore, we evaluated the importance of soil ingestion as a route for the uptake of contaminants in lizards. We used sand as a substitute for soil during the present study. Different groups of leopard geckos (Eublepharis macularius) were provided with a control and five sodium selenite-spiked sand mixtures during a 28-d study. Twenty lizards were assigned to a control group and to each of five selenium-spiked sand mixtures that consisted of nominal selenium (Se) concentrations of 0.05, 0.46, 4.57, 11.41, and 22.83 mg Se/kg dry sand. Leopard geckos readily ingested the Se-spiked sand. We observed concentration-related effects in several endpoints. Overall growth in body mass was the most sensitive endpoint and was significantly (p < 0.05) lower in lizards that ingested the 4.57, 11.41, and 22.83 mg Se/kg sand mixtures compared to controls. Growth in snout-vent length, mean daily food ingestion, and food conversion efficiency were less sensitive and were significantly (p < 0.05) lower in lizards that ingested the 11.41 and 22.83 mg Se/kg sand mixtures compared to controls. Although our results are based on nominal amounts of Se ingested, leopard geckos appear to be as sensitive to sodium selenite as birds and mammals. The present study suggests that ingestion of soil could be an important potential route for the uptake of soil contaminants in some reptiles and should be evaluated in ecotoxicological studies and risk analyses of reptiles.