1,078 research outputs found

    Studying the effects of in-vehicle information systems on driver visual behaviour – implications for design

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    In-vehicle information systems (IVIS) are a common feature in modern vehicles. The interaction of drivers with IVIS when driving must be considered to minimise distraction whilst maintaining the benefits provided. This research investigates the glance behaviours of drivers, assessed from video data, when using two functions – a personal navigation device (study 1) and a green driving advisory device (study 2). The main focus was to establish the number of glances of 2 seconds or more to the IVIS and relate this to driver safety (as stipulated in new guidelines for use of IVIS proposed by NHTSA). In study 1, the percentage of eyes- off-road time for drivers was much greater in the experimental (with device) condition compared to the baseline condition (14.3% compared to 6.7%) but, whilst glances to the personal navigation device accounted for the majority of the increase, there were very few which exceeded 2 seconds. Drivers in study 2 spent on average 4.3% of their time looking at the system, at an average of 0.43 seconds per glance; no glances exceeded 2 seconds. The research showed that ordinary use of IVIS (excluding manual interaction) does not lead to driver visual distraction and therefore the impact on safety is minimal. The results of the study have important design implications for future in-vehicle information systems

    Autonomous vehicle validation - are we just guessing or can we predict the future?

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    At present there exists no standardised, systematic or structured methodology for the validation of autonomous pod vehicles. The lack of process is compounded by minimal real-world collision or near miss data covering this vehicle type. This gap in knowledge may present a significant obstacle in autonomous pod vehicle development and consumer uptake from two sides; firstly, the scarcity of data for road safety practitioners to develop into appropriate test scenarios and secondly the lack of perceived transparency by the OEMs could form the perception that there is negligible vehicle development and manufacturer accountability, resulting in lack of trust from the end users. To counter this knowledge gap this paper aims to provide more information on initial steps into the definition of a systematic reference dataset which reflects both autonomous pod use and the capabilities of the vehicles to be tested. Due to the lack of real world data in the short term, it will be necessary to develop vehicle validation scenarios for autonomous pods based entirely on non-autonomous collisions of comparable vehicle types. Although there are currently no specific well-tested frameworks to follow, the approach discussed applies proven methodological principals from the field of general product design which assumes that if the design envelope is set correctly then any product that meets this, no matter how outlandish, will be valid

    The Relation of Adolescent Substance Use to Young Adult Autonomy, Positive Activity Involvement, and Perceived Competence

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    The current paper uses data from a longitudinal study of a high-risk sample to test the relation between adolescent alcohol and drug use and later young adult autonomy, positive activity involvement, and perceived competence. Participants (children of alcoholics and demographically matched controls) were assessed in three annual interviews in adolescence (mean age: 12.7 years at Time 1) and then again 5–7 years later, in young adulthood (median age: 20 years). Path analyses and latent growth curve models tested the effects of adolescent substance use on both selfreported and collateral-reported outcomes, controlling for correlated risk factors (parental alcoholism, adolescent psychopathology, and parental support), preexisting levels of the outcome, and concurrent young adult substance use. Results showed that adolescent drug use had a significant, unique negative effect on later autonomy and perceived competence. Alcohol use effects were more complex. Adolescent heavy drinking was associated with less positive adult outcomes, but more so in collateral reports than in self-reported outcomes. Moreover, young adult heavy drinking was either uncorrelated with or positively correlated with higher levels of perceived competence, suggesting different developmental significance of alcohol use in adolescence than in young adulthood

    A Preliminary Formation Flying Orbit Dynamics Analysis for Leonardo-BRDF

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    Leonardo-BRDF is a new NASA mission concept proposed to allow the investigation of radiative transfer and its effect on the Earth's climate and atmospheric phenomenon. Enabled by the recent developments in small-satellite and formation flying technology, the mission is envisioned to be composed of an array of spacecraft in carefully designed orbits. The different perspectives provided by a distributed array of spacecraft offer a unique advantage to study the Earth's albedo. This paper presents the flight dynamics analysis performed in the context of the Leonardo-BRDF science requirements. First, the albedo integral is investigated and the effect of viewing geometry on science return is studied. The method used in this paper, based on Gauss quadrature, provides the optimal formation geometry to ensure that the value of the integral is accurately approximated. An orbit design approach is presented to achieve specific relative orbit geometries while simultaneously satisfying orbit dynamics constraints to reduce formation-keeping fuel expenditure. The relative geometry afforded by the design is discussed in terms of mission requirements. An optimal Lambert initialization scheme is presented with the required DeltaV to distribute all spacecraft from a common parking orbit into their appropriate orbits in the formation. Finally, formation-keeping strategies are developed and the associated DeltaV's are calculated to maintain the formation in the presence of perturbations

    Walmart Impact on the Finance and Insurance Industry

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    Purpose This paper investigates the effect of Walmart presence on professional service firms within the finance and insurance sector. This paper also discusses the finance and insurance industry’s place within the Walmart ripple effect—changed retail sector leads to changed professional support services resulting in altered levels of social capital within the community. Design/Methodology The study uses county-level data from the state of Nebraska to examine the relationship between cumulative Walmart exposure and the number of firms, number of employees, and payroll levels within the finance and insurance (F&I) sector. These same variables are also investigated within two specific F&I industries—insurance and banking. Findings The study documents a negative association between cumulative Walmart presence and the number of employees in the finance and insurance industry and a positive relationship between Walmart exposure and F&I payroll levels. The insurance industry results are consistent with the F&I sector result relating to payroll, but show a significant positive relationship between cumulative Walmart exposure and number of insurance agencies. Empirical results from the commercial banking industry are consistent with both the F&I sector and insurance industries with a positive relationship between Walmart presence over time and payroll levels. Originality/value This study contributes to the Walmart effect literature by considering the impact of Walmart presence beyond the retail sector. The paper investigates the effect of Walmart on the finance and insurance profession, a sector that 1) competes directly with Walmart Supercenters for money services, 2) provides support services for retail businesses impacted by Walmart services, and 3) potentially suffers from centralized benefits provided to employees by Walmart headquarters rather than local insurers. The paper concludes that the mixed impact on professional firms results in social capital that could be both strengthened and challenged by Walmart presence

    Data Exploration, Quality Control and Testing in Single-Cell qPCR-Based Gene Expression Experiments

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    Cell populations are never truly homogeneous; individual cells exist in biochemical states that define functional differences between them. New technology based on microfluidic arrays combined with multiplexed quantitative polymerase chain reactions (qPCR) now enables high-throughput single-cell gene expression measurement, allowing assessment of cellular heterogeneity. However very little analytic tools have been developed specifically for the statistical and analytical challenges of single-cell qPCR data. We present a statistical framework for the exploration, quality control, and analysis of single-cell gene expression data from microfluidic arrays. We assess accuracy and within-sample heterogeneity of single-cell expression and develop quality control criteria to filter unreliable cell measurements. We propose a statistical model accounting for the fact that genes at the single-cell level can be on (and for which a continuous expression measure is recorded) or dichotomously off (and the recorded expression is zero). Based on this model, we derive a combined likelihood-ratio test for differential expression that incorporates both the discrete and continuous components. Using an experiment that examines treatment-specific changes in expression, we show that this combined test is more powerful than either the continuous or dichotomous component in isolation, or a t-test on the zero-inflated data. While developed for measurements from a specific platform (Fluidigm), these tools are generalizable to other multi-parametric measures over large numbers of events.Comment: 9 pages, 5 figure

    Designing an online dissertation research community of practice

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    This design case describes phase one (pilot phase) of an intervention strategy aimed to support students in a limited–residency doctoral program. Specifically, this case documents the process and decisions that were made along the way to design an online research community of practice (CoP) for students who have completed coursework and are working on their dissertations in the field of instructional design and technology. The case includes the designers’ guiding framework, a detailed description of the case including the site, participant and platform selection, and the preliminary state of the design. To date, a design team is in place, a guiding framework for the design of the CoP is established, a needs analysis has been conducted, the participants have been identified, the CoP strategy has been defined, the site has launched, and students are just now beginning to become a part of this online community. It will take time to cultivate the community and determine whether the design is effective in achieving the community’s goals. Data collection and documentation of design decisions continue as the design and development of the online CoP emerges

    A Grounded Theory of Connectivity and Persistence in a Limited Residency Doctoral Program

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    Limited-residency and online doctoral programs have an attrition rate significantly higher than traditional programs. This grounded-theory study focused on issues pertaining to communication between students, their peers and faculty and how interpersonal communication may affect persistence. Data were collected from 17 students actively working on their dissertation in a limited-residency educational technology program. The resultant theory indicated that students felt communication between themselves and peers is possible but not common. Students also indicated that dissertation supervisors are readily accessible but longer than expected response times may contribute to a lack of student success. The results suggest the development and effective use of an online community of practice will support the communication needs of students and faculty
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