352 research outputs found

    Telerobotic controller development

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    To meet NASA's space station's needs and growth, a modular and generic approach to robotic control which provides near-term implementation with low development cost and capability for growth into more autonomous systems was developed. The method uses a vision based robotic controller and compliant hand integrated with the Remote Manipulator System arm on the Orbiter. A description of the hardware and its system integration is presented

    Unified traction and battery charging systems for electric vehicles: a sustainability perspective

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    This paper presents an analysis of unified traction and battery charging systems for electric vehicles (EVs), both in terms of operation modes and in terms of implementation cost, when compared to dedicated solutions that perform the same operation modes. Regarding the connection of the EV battery charging system with the power grid, four operation modes are analyzed: (1) Grid–to–Vehicle (G2V); (2) Vehicle–to–Grid (V2G); (3) Vehicle–to–Home (V2H); and (4) Vehicle–for–Grid (V4G). With an EV unified system, each of these operation modes can be used in single–phase and three–phase power grids. Furthermore, a cost estimation is performed for an EV unified system and for dedicated systems that can perform the same functionalities, in order to prove the benefits of the EV unified approach. The cost estimation comprises two power levels, namely 6 kW, single–phase, related to domestic installations, and 50 kW, three–phase, related to industrial installations. The relevance of unified traction and battery charging systems for EVs is proven for single–phase and three–phase power grids.This work has been supported by FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2019. This work has been supported by the FCT Project DAIPESEV PTDC/EEI-EEE/30382/2017, and by the FCT Project new ERA4GRIDs PTDC/EEI-EEE/30283/2017

    Alterations in functional connectivity for language in prematurely born adolescents

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    Recent data suggest recovery of language systems but persistent structural abnormalities in the prematurely born. We tested the hypothesis that subjects who were born prematurely develop alternative networks for processing language. Subjects who were born prematurely (n = 22; 600–1250 g birth weight), without neonatal brain injury on neonatal cranial ultrasound, and 26 term control subjects were examined with a functional magnetic resonance imaging (fMRI) semantic association task, the Wechsler Intelligence Scale for Children-III (WISC-III) and the Clinical Evaluation of Language Fundamentals (CELF). In-magnet task accuracy and response times were calculated, and fMRI data were evaluated for the effect of group on blood oxygen level dependent (BOLD) activation, the correlation between task accuracy and activation and the functional connectivity between regions activating to task. Although there were differences in verbal IQ and CELF scores between the preterm (PT) and term control groups, there were no significant differences for either accuracy or response time for the in-magnet task. Both groups activated classic semantic processing areas including the left superior and middle temporal gyri and inferior frontal gyrus, and there was no significant difference in activation patterns between groups. Clear differences between the groups were observed in the correlation between task accuracy and activation to task at P < 0.01, corrected for multiple comparisons. Left inferior frontal gyrus correlated with accuracy only for term controls and left sensory motor areas correlated with accuracy only for PT subjects. Left middle temporal gyri correlated with task accuracy for both groups. Connectivity analyses at P < 0.001 revealed the importance of a circuit between left middle temporal gyri and inferior frontal gyrus for both groups. In addition, the PT subjects evidenced greater connectivity between traditional language areas and sensory motor areas but significantly fewer correlated areas within the frontal lobes when compared to term controls. We conclude that at 12 years of age, children born prematurely and children born at term had no difference in performance on a simple lexical semantic processing task and activated similar areas. Connectivity analyses, however, suggested that PT subjects rely upon different neural pathways for lexical semantic processing when compared to term controls. Plasticity in network connections may provide the substrate for improving language skills in the prematurely born

    Effect of SCBA Design and Firefighting Induced Fatigue on Balance, Gait and Safety of Movement

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    Here we presented a report for the Fire Service documenting an examination of the effect of SCBA and firefighting induced fatigue on firefighters’ gait, balance, and safety of movement. More detailed, peer-reviewed scientific reports can be found in academic literature and are available at the Illinois Fire Service Institute. Fireground operations are inherently dangerous, with overexertion/ strain and slips, trips, and falls being the two leading causes of injury. 26.5% of fireground injuries are a result of overexertion or strain, conditions which may be accelerated by the fact that firefighting activities can induce near maximal heart rates and elevated core temperatures. The high levels of effort and exertion needed to complete such activities may be made worse by the firefighter’s turnout gear and self-contained breathing apparatus (SCBA). Anecdotal evidence suggests a trend in the Fire Service toward extended duration SCBA (greater than 30-min), which may further increase the physical demand on the firefighter. Further, nearly 23% of fireground injuries are the result of a slip, trip, and/or fall. These injuries often occur while or following firefighting activities, and may often be a result of the fatigue those activities have induced in the firefighter. Extended duration SCBA are typically heavier and may reduce the time before the firefighter becomes fatigued. Thirty firefighters were recruited to take part in repeated-measures study to examine the effects of SCBAs and duration of work cycle have on physiological strain, balance, gait, and safety of movement. Firefighters completed seven different conditions with various SCBA (30, 45, and 60-minute standard cylindrical SCBA and a low-profile 45-min prototype) and durations of simulated firefighting (one or two bouts) in a heated environmental chamber (117°F (47°C)). Four activities were performed (stair climb, hose advance, secondary search, and overhaul) on two-minute work-rest cycles. Subjects also completed an obstacle course designed to test their gait and functional balance prior to, and immediately after the simulated firefighting activities. Following firefighting activity firefighters had elevated heart rates and core temperatures. The firefighters also generally performed worse in the obstacle course. The size of the SCBA had a minimal impact on the firefighters, though it did decrease the performance on a Functional Balance Test. The low-profile prototype SCBA impacted the firefighters in a similar manner as the traditional cylindrical SCBA, though firefighters generally took longer to pass through a 16-inch on-center stud space. When firefighters completed multiple bouts of simulated firefighting activity heart rates and core temperatures were elevated relative to a single bout while the number of repetitions performed during each activity decreased. Performance during the obstacle course was also more negatively impacted following a second bout of activity than after a single bout.U.S. Department of Homeland Security through the Assistance to Firefighters Grant Program (Research and Development grant: EMW-2010-FP-01606)Ope

    Neural correlates of enhanced visual short-term memory for angry faces: An fMRI study

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    Copyright: © 2008 Jackson et al.Background: Fluid and effective social communication requires that both face identity and emotional expression information are encoded and maintained in visual short-term memory (VSTM) to enable a coherent, ongoing picture of the world and its players. This appears to be of particular evolutionary importance when confronted with potentially threatening displays of emotion - previous research has shown better VSTM for angry versus happy or neutral face identities.Methodology/Principal Findings: Using functional magnetic resonance imaging, here we investigated the neural correlates of this angry face benefit in VSTM. Participants were shown between one and four to-be-remembered angry, happy, or neutral faces, and after a short retention delay they stated whether a single probe face had been present or not in the previous display. All faces in any one display expressed the same emotion, and the task required memory for face identity. We find enhanced VSTM for angry face identities and describe the right hemisphere brain network underpinning this effect, which involves the globus pallidus, superior temporal sulcus, and frontal lobe. Increased activity in the globus pallidus was significantly correlated with the angry benefit in VSTM. Areas modulated by emotion were distinct from those modulated by memory load.Conclusions/Significance: Our results provide evidence for a key role of the basal ganglia as an interface between emotion and cognition, supported by a frontal, temporal, and occipital network.The authors were supported by a Wellcome Trust grant (grant number 077185/Z/05/Z) and by BBSRC (UK) grant BBS/B/16178

    Thermal response to firefighting activities in residential structure fires: impact of job assignment and suppression tactic

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    Firefighters’ thermal burden is generally attributed to high heat loads from the fire and metabolic heat generation, which may vary between job assignments and suppression tactic employed. Utilising a full-sized residential structure, firefighters were deployed in six job assignments utilising two attack tactics (1. Water applied from the interior, or 2. Exterior water application before transitioning to the interior). Environmental temperatures decreased after water application, but more rapidly with transitional attack. Local ambient temperatures for inside operation firefighters were higher than other positions (average ~10–30 °C). Rapid elevations in skin temperature were found for all job assignments other than outside command. Neck skin temperatures for inside attack firefighters were ~0.5 °C lower when the transitional tactic was employed. Significantly higher core temperatures were measured for the outside ventilation and overhaul positions than the inside positions (~0.6–0.9 °C). Firefighters working at all fireground positions must be monitored and relieved based on intensity and duration. Practitioner Summary: Testing was done to characterise the thermal burden experienced by firefighters in different job assignments who responded to controlled residential fires (with typical furnishings) using two tactics. Ambient, skin and core temperatures varied based on job assignment and tactic employed, with rapid elevations in core temperature in many roles.This work was supported by the Department of Homeland Security Fire Prevention and Safety Grant [#EMW-2013-FP-00766].Ope

    Integrated system for traction and battery charging of electric vehicles with universal interface to the power grid

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    This paper proposes an integrated system for traction and battery charging of electric vehicles (EVs) with universal interface to the power grid. In the proposed system, the power electronics converters comprising the traction drive system are also used for the battery charging system, reducing the required hardware, meaning the integrated characteristic of the system. Besides, this interface is universal, since it can be performed with the three main types of power grids, namely: (1) Single-phase AC power grids; (2) Three-phase AC power grids; (3) DC power grids. In these three types of interfaces with the power grid, as well as in the traction drive operation mode, bidirectional operation is possible, framing the integration of this system into an EV in the context of smart grids. Moreover, the proposed system endows an EV with an on-board fast battery charger, whose operation allows either fast or slow battery charging. The main contributes of the proposed system are detailed in the paper, and simulation results are presented in order to attain the feasibility of the proposed system.This work has been supported by COMPETE: POCI-01-0145-FEDER-007043 and FCT -Fundacao para a Ciencia e Tecnologia within the Project Scope: UID/CEC/00319/2013. This work has been supported by FCT within the Project Scope DAIPESEV - Development of Advanced Integrated Power Electronic Systems for Electric Vehicles: PTDC/EEI-EEE/30382/2017. Mr. Tiago Sousa is supported by the doctoral scholarship SFRH/BD/134353/2017 granted by the Portuguese FCT agency. This work is part of the FCT project 0302836 NORTE-01-0145-FEDER-030283

    Sport fans' roles in value co-creation

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    Research question The sports industry has witnessed sustained growth. The cultural, symbolic and stakeholder-embedded nature of sport provides a dynamic setting for developing service research. In this context, an evolution in the logic of value creation can be observed; fans are no longer passive receivers of value but, instead, can be active value co-creators. The sport fan exhibits distinctive characteristics and an ability and willingness to integrate resources and co-produce value propositions, which necessitates an understanding of fan value co-creation. We answer one key research question: what is the role of fans in value co-creation in sports? We do so by conceptually exploring the processes through which sport fans co-create and provide value propositions. Research methods We use case exemplars to provide a base for the theoretical consideration of the role of sport fans in value co-creation. We verify and consolidate the service-dominant logic (SDL) in the sport context. However, due to the high level of abstraction of the SDL as a general theory, we utilize consumer culture theory (CCT) as a middle range theory (MRT) to bridge the gap between contextual descriptions of the role of fans and the SDL. Results and findings Fans evaluate, redefine and reposition value propositions in different sport settings. The three roles of assimilators, adaptors and authenticators in value co-creation are identified through five case exemplars. We extend the theoretical understanding of the processes through which sport fans co-create value. Implications Knowledge of the distinctive characteristics of sport fans and their roles in value co-creation will assist managers in developing effective marketing propositions. Our theoretical contribution will generate new lines of research in the field
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