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211.
This study aims to examine pedestrians' crossing decision, body parts' movement and full body movement, just before and during road crossing in a simulated setup. To accomplish this, a novel experimental setup for analyzing pedestrians’ crossing behavior and motion was developed where the simulated display was synchronized with a 3D motion capturing system. Twenty participants, divided into control and an experimental time pressure group, observed sixteen short (less than 30 s) and long road (70 s or more) crossing scenarios with varying crossing opportunities. Based on the crossing opportunities they were asked to cross a 3.6 m wide one-lane one way urban road. It was found that the crossing initiation process consists of four incremental movements of body parts: the head and the shoulder first; the hip, wrist and elbow second; the knee as a separate joint, and finally the ankle. Results showed that pedestrians’ decision to cross and body parts movement are influenced by time pressure and wait time for a safe crossing opportunity. Specifically, pedestrians prepare their body parts earlier, initiate their crossing earlier, and adjust their speed to compensate for the risk taken in less safe or non-safe crossing opportunities. Within the control group, women tended to be more risk avoiding than men, however those differences disappeared in the time pressure group. Most importantly, the findings provide initial evidence that this novel simulation configuration can be used to gain precise knowledge of pedestrians’ decision-making and movement processes. 相似文献
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Motor vehicle collisions are the leading cause of death in people ages 5–34 in the US, and secondary task engagement, such as talking on a cell phone, is a leading contributor to motor vehicle collisions. The negative effects of secondary task engagement on driving performance has become a prominent recent topic of study given the increasing amount of time drivers engage in distracted driving. However, few studies have examined the effects of secondary task engagement while driving on health related outcomes such as cardiovascular reactivity. Cardiovascular reactivity, as measured by heart rate and blood pressure, has been used in previous studies as a means of measuring effort in task engagement as well as a means to predict cardiovascular disease and stroke. This study investigates the effect of secondary task (talking on a cell phone, texting, and driving with no task) while driving in a simulator on cardiovascular reactivity. Using difference scores between baseline (a period of inactivity) and stimulus (driving with no task and driving with secondary tasks), a repeated measures analysis of variance using a mixed model approach was used to determine the effect of secondary task on cardiovascular reactivity. Findings indicated that talking on a cell phone while driving significantly increased cardiovascular reactivity via heart rate and blood pressure compared to driving with no task. Texting while driving did not differ significantly from driving with no task. This study demonstrates the need for more research on the long term effects of secondary tasks while driving on cardiovascular reactivity and for assessing the risks associated with secondary task use while driving on developing cardiovascular disease or stroke. 相似文献
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On rough terrain, excessive wheel slippage is easily generated by changes of surface conditions such as soil types and geometries. It induces considerable loss of wheel traction and battery energy. To prevent this, wheeled robots should consistently recognize the current situation generated between wheel and surface. And also wheeled robots are required to optimally control wheel motion in limited wheel traction and battery capacity. Therefore, this paper proposes a novel wheel control algorithm based on slip optimization of traction and energy, which is adaptive to change of surface condition. Proposed wheel control algorithm is called Traction-Energy Balancing Adaptive Control (TEB) in this paper and TEB assigns optimized rotation speed to each wheel by observing wheel slip ratio which is a key parameter of TEB. As functions of TEB, TEB is largely divided into three main parts; (1) slip optimizer (2) slip controller (3) SC-compensator. In the slip optimizer, two optimal slip models were derived as a function of slip ratios regarding maximum traction and tractive efficiency using experimental data about wheel-terrain interaction in three types of soil (grass, gravel and sand). And the optimal slip models were employed in order to determine a desired slip value of wheel with observation of a change in actual robot velocity as control input in the slip controller. For optimal slip control, the proposed slip controller is based on conventional PID controller with compensating disturbance in the controller (SC-compensator) which occurs by change of surface shapes. In the SC-compensator, radial function networks (RBFN) was applied in the slip controller and RBFN was of help to readjust previously set PID gains depending on occurred slip error. Finally, TEB was experimentally verified by controlling a real robot having four wheels on various terrain types. 相似文献
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Background and objectives: Developmental theorists posit that temperament contributes to preadolescent’s stress response styles. Findings from empirical studies, however, have yielded mixed results, thus indicating a need to consider moderators of this relation. Utilizing an analytic framework guided by resiliency theory [Zimmerman, M. A. (2013). Resiliency theory: A strengths-based approach to research and practice for adolescent health. Health Education &; Behavior, 40, 381–383], this study examined achievement goal orientation as a moderator of the relation between temperament and stress response styles.Methods: 96 preadolescent–parent dyads (Mage?=?10.30 years, range?=?9–12 years) participated in the study. Preadolescents reported on their achievement goal orientation, coping and involuntary stress responses (ISRs) styles and a parent reported on children’s temperament.Results: Multiple regressions revealed that effortful control positively predicted preadolescent’s predominant use of engagement coping and negatively predicted predominance of ISRs, but only for children with a predominant mastery goal orientation. For preadolescents with a predominant performance goal orientation, effortful control negatively predicted the predominant use of engagement coping and positively predicted predominance of ISRs. Negative affectivity and its interaction with goal orientation did not predict coping or ISR styles.Conclusions: Findings suggest that a predominant mastery goal orientation may function as a promotive factor by enhancing the contribution of effortful control to engagement coping styles and buffering against unmanaged reactivity. 相似文献
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This study identified the level of trunk control of healthy term infants aged from six to nine months. This cross-sectional study included fifty-five infants aged from six to nine months. The levels of trunk control was investigated by using the Segmental Assessment Trunk Control (SATCo). The infants remained seated on a wooden bench and a neutral pelvic position was maintained. The SATCo score was considered as dependent variable. The results showed that infants aged six and seven months presented levels of trunk control in the thoracic region while infants aged from eight to nine months presented full trunk control. These results demonstrate that younger infants present less levels of trunk control while older infants present full trunk control, confirming that trunk control development takes place in a segmental way and in a cephalocaudal direction. These results also might be used as a reference to distinguish infants that show a delay in trunk control from those who have suitable motor development and, thus intervene at an early stage to minimize later delays in these infantś global motor development. 相似文献
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Calming an aggressor through spontaneous post‐conflict triadic contacts: Appeasement in Macaca tonkeana 下载免费PDF全文