From vision to action: Experiments and models of steering control during driving.

Experienced drivers performed simple steering maneuvers in the absence of continuous visual input. Experiments conducted in a driving simulator assessed drivers' performance of lane corrections during brief visual occlusion and examined the visual cues that guide steering. The dependence of steering behavior on heading, speed, and lateral position at the start of the maneuver was measured. Drivers adjusted steering amplitude with heading and performed the maneuver more rapidly at higher speeds. These dependencies were unaffected by a 1.5-s visual occlusion at the start of the maneuver. Longer occlusions resulted in severe performance degradation. Two steering control models were developed to account for these findings. In the 1st, steering actions were coupled to perceptual variables such as lateral position and heading. In the 2nd, drivers pursued a virtual target in the scene. Both models yielded behavior that closely matches that of human drivers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Feedback factors in steering and tracking behavior.

Investigated the assumption that, in self-produced behavior, steering and target represent distinctive modes of reponse which are based, respectively, on perception and guidance of body movements in relation to the environment (steering) and on perception and guidance in relation to movement of environmental targets (stimulus tracking). These 2 modes of guided performance were compared using 7 Ss under controlled conditions in relation to the effects of feedback delay. Steering was degraded as much if not more than stimulus tracking by feedback delays between hand motion and the visual display involved in the different tasks. Steering performance, as in control of vehicles, thus may be affected seriously be feedback delays produced by powered steering and tracking devices and by inertia of action of a vehicle in relation to steering action at different speeds. Results theoretically clarify the feedback relations between self-produced and stimulus-response patterns of performance and learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The influence of advance information about target location and visual feedback on movement planning and execution.

This study was designed to determine if movement planning strategies incorporating the use of visual feedback during manual aiming are specific to individual movements. Advance information about target location and visual context was manipulated using precues. Participants exhibited a shorter reaction time and a longer movement time when they were certain of the target location and that vision would be available. The longer movement time was associated with greater time after peak velocity. Under conditions of uncertainty, participants prepared for the worst-case scenario. That is, they spent more time organizing their movements and produced trajectories that would be expected from greater open-loop control. Our results are consistent with hierarchical movement planning in which knowledge of the movement goal is an essential ingredient of visual feedback utilization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Control of a virtual vehicle influences postural activity and motion sickness.

Everyday experience suggests that drivers are less susceptible to motion sickness than passengers. In the context of inertial motion (i.e., physical displacement), this effect has been confirmed in laboratory research using whole body motion devices. We asked whether a similar effect would occur in the context of simulated vehicles in a visual virtual environment. We used a yoked control design in which one member of each pair of participants played a driving video game (i.e., drove a virtual automobile). A recording of that performance was viewed (in a separate session) by the other member of the pair. Thus, the two members of each pair were exposed to identical visual motion stimuli, but the risk of behavioral contagion was minimized. Participants who drove the virtual vehicle (drivers) were less likely to report motion sickness than participants who viewed game recordings (passengers). Data on head and torso movement revealed that drivers tended to move more than passengers, and that the movements of drivers were more predictable than the movements of passengers. Before the onset of subjective symptoms of motion sickness movement differed between participants who (later) reported motion sickness and those who did not, consistent with a prediction of the postural instability theory of motion sickness. The results confirm that control is an important factor in the etiology of motion sickness and extend this finding to the control of noninertial virtual vehicles. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Specificity of practice: Interaction between concurrent sensory information and terminal feedback.

In 2 experiments, the authors investigated a potential interaction involving the processing of concurrent feedback using design features from the specificity of practice literature and the processing of terminal feedback using a manipulation from the guidance hypothesis literature. In Experiment 1, participants produced (198 trials) flexion-extension movements to reproduce a specific pattern of displacement over time with or without vision of the limb position and with 100% or 33% knowledge of results (KR) frequency. The transfer test was performed without vision and KR. In Experiment 2, the authors assessed whether sensory information processing was modulated by the amount of practice. Participants performed 54 or 396 trials under a 100% or a 33% KR frequency with vision before being transferred to a no-vision condition without KR. Results of both experiments indicated that the Vision-33% condition suffered a larger detrimental effect of withdrawing visual information than the Vision-100% condition. Experiment 2 indicated that this detrimental effect increased with practice. These results indicated the reduction in terminal feedback prompted participants to more deeply process the concurrent visual information thus reinforcing their dependency on the visual information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Improving the effectiveness of computer-delivered personalized drinking feedback interventions for college students.

This study evaluated methods of enhancing college students' retention of information provided to them in a computer-delivered personalized drinking feedback intervention and whether enhanced retention reduced alcohol consumption during the two-week period following the intervention. Participants were 98 college students who reported at least one heavy drinking episode in the past two weeks. After participating in an online, personalized drinking feedback intervention, students were randomly assigned to one of three experimental conditions: 1) typical, in which they were simply sent home, 2) reading, in which they were asked to spend the next 20 minutes re-reading the feedback, and 3) recall, in which they were asked to spend the next 20 minutes writing down as much of the information from the feedback as they could remember. Two weeks following the intervention, participants completed a recall test and provided information on their alcohol use during the previous two weeks. Results indicated that participants in the reading and recall conditions retained more of the feedback information than did participants in the typical condition. In addition, participants in the reading and recall conditions reported reduced alcohol consumption in the two-week period following the intervention, compared to those in the typical condition. Information retention partially mediated the effects of the reading and recall conditions on drinking outcomes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Role of Visual and Nonvisual Information in the Control of Locomotion.

During locomotion, retinal flow, gaze angle, and vestibular information can contribute to one's perception of self-motion. Their respective roles were investigated during active steering: Retinal flow and gaze angle were biased by altering the visual information during computer-simulated locomotion, and vestibular information was controlled through use of a motorized chair that rotated the participant around his or her vertical axis. Chair rotation was made appropriate for the steering response of the participant or made inappropriate by rotating a proportion of the veridical amount. Large steering errors resulted from selective manipulation of retinal flow and gaze angle, and the pattern of errors provided strong evidence for an additive model of combination. Vestibular information had little or no effect on steering performance, suggesting that vestibular signals are not integrated with visual information for the control of steering at these speeds. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Delayed feedback in steering during learning and transfer of learning.

Compares accuracy in steering behavior as a characteristic mode of dynamic self-generation of stimuli by movement, with stimulus tracking in which response guidance is determined primarily by movements of environmental stimuli. Breath-generated variations in a visual target were used to measure steering of 24 female undergraduates. The hypotheses were that learning in tracking the respiration-generated targets would proceed more rapidly than that of tracking an environmental stimulus and that transfer of performance with the self-generated targets also would be superior. Results based on exact calibration of the equality of error control of the 2 modes of tracking confirm these assumptions. It was also found that steering and stimulus tracking were differentially affected in the learning and transfer trial series by manual-visual feedback delays between 0-1.5 sec. Results are explained theoretically by the assumption that steering reactions involved built-in stereotypical spatial and temporal coordinations between eye, hand, and body movements which were not present in the stimulus tracking. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Gaucher disease: four families with previously undescribed mutations

A large-scale sequencing project requires a tool to control the quality of the input data because a sizable number of trace data may be of low quality. If these data are allowed to enter the sequence assembly pipeline, harm will be done. Hence, it is important to detect such data as soon as possible. MTT (Move-Track-Trim) is a software package analyzing the quality of the lanes. It subjects each lane to a series of tests, and if a lane does not pass all tests, it is flagged as a "bad" lane. The use has a chance to examine both the "good" and the "bad" lanes and reclassify a "bad" lane as "good," or vice versa. Alternatively, the user may decide to retrack the gel or get rid of some lanes altogether. As a by-product of the analysis, MTT performs other useful functions. It trims the lanes and compresses the lane files and moves them to the directories where assembly is carried out. It also generates some useful statistics describing the quality of the gel.     

Active gaze, visual look-ahead, and locomotor control.

The authors examined observers steering through a series of obstacles to determine the role of active gaze in shaping locomotor trajectories. Participants sat on a bicycle trainer integrated with a large field-of-view simulator and steered through a series of slalom gates. Steering behavior was determined by examining the passing distance through gates and the smoothness of trajectory. Gaze monitoring revealed which slalom targets were fixated and for how long. Participants tended to track the most immediate gate until it was about 1.5 s away, at which point gaze switched to the next slalom gate. To probe this gaze pattern, the authors then introduced a number of experimental conditions that placed spatial or temporal constraints on where participants could look and when. These manipulations resulted in systematic steering errors when observers were forced to use unnatural looking patterns, but errors were reduced when peripheral monitoring of obstacles was allowed. A steering model based on active gaze sampling is proposed, informed by the experimental conditions and consistent with observations in free-gaze experiments and with recommendations from real-world high-speed steering. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of feedback delay on eye-hand synchronism in steering behavior.

Used real-time computer methods of controlling feedback factors in eye tracking to compare accuracy in tracking environmentally-generated and hand-generated visual targets in steering behavior of 5 undergraduates. Feedback delays of .1 and .2 sec. between hand and target movement produced a time lag of eye motion with respect to the hand-produced target action. Results confirm the assumption that steering and stimulus tracking represent different modes of response and are subject to different conditions of delay and displacement of action feedback of body movements. The main effect of feedback delays on eye tracking in steering was to restrict the normal capability of the eye to predict the course of self-generated stimulus movements by reducing the interval of time between hand action and eye response beyond the magnitude of the actual delay interval. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Controlling steering and judging heading: Retinal flow, visual direction, and extraretinal information.

The contribution of retinal flow (RF), extraretinal (ER), and egocentric visual direction (VD) information in locomotor control was explored. First, the recovery of heading from RF was examined when ER information was manipulated; results confirmed that ER signals affect heading judgments. Then the task was translated to steering curved paths, and the availability and veracity of VD were manipulated with either degraded or systematically biased RE. Large steering errors resulted from selective manipulation of RF and VD, providing strong evidence for the combination of RF, ER, and VD. The relative weighting applied to RF and VD was estimated. A point-attractor model is proposed that combines redundant sources of information for robust locomotor control with flexible trajectory planning through active gaze. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A randomized clinical trial of a brief, mailed intervention for symptoms of depression.

This research evaluated the efficacy of a brief, mailed personalized feedback intervention designed to alleviate depressed mood and antecedents (ineffective coping and hopelessness). College students (N = 177) were randomly assigned to intervention or control group following a baseline assessment. A week after completing the baseline assessment, participants in the intervention condition were mailed feedback and information detailing their mood, coping strategies, as well as suggestions for enhancing mood. Results indicated that feedback was effective in reducing depressive symptoms, hopelessness, and among men, increasing willingness to use coping strategies at the 1-month follow-up. Hopelessness mediated reductions in depressive symptoms. Results support the use of personalized feedback as a low-cost, initial intervention for college students suffering from symptoms of depression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Role of Feedback Information for Calibration and Attunement in Perceiving Length by Dynamic Touch.

Two processes have been hypothesized to underlie improvement in perception: attunement and calibration. These processes were examined in a dynamic touch paradigm in which participants were asked to report the lengths of unseen, wielded rods differing in length, diameter, and material. Two experiments addressed whether feedback informs about the need for reattunement and recalibration. Feedback indicating actual length induced both recalibration and reattunement. Recalibration did not occur when feedback indicated only whether 2 rods were of the same length or of different lengths. Such feedback, however, did induce reattunement. These results suggest that attunement and calibration are dissociable processes and that feedback informs which is needed. The observed change in variable use has implications also for research on what mechanical variables underlie length perception by dynamic touch. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of aging on planning and implementing arm movements.

In Exps 1 and 2, aiming movements were performed with and without visual feedback in young and elderly adults. The initial (acceleration and deceleration phases) and secondary movement components were analyzed. Although deceleration phase accuracy decreased without visual feedback in both age groups, accuracy diminished as movement amplitude increased only in the elderly. This suggested that the elderly were more dependent on visual feedback to modify motor programs for longer duration movements. Velocity also increased less with increasing amplitude and target size in the elderly, which was related to impaired preprogramming (acceleration phase) and implementation (deceleration phase) of higher forces. This conclusion was confirmed directly in Exp 2 because only the deceleration phase was affected by the removal of a visual feedback of arm position when availability of visual information could not be predicted before movement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Analyzing Performance of ETC Plazas Using New Computer Software

This paper investigates the sensitivity of the peak hour plaza delay to market penetration of the electronic toll collection (ETC) system using the toll plaza simulation model developed by the Transportation Systems Institute at the University of Central Florida. This microscopic and stochastic computer software was applied to the busiest toll plaza in Orlando, Florida. The findings indicate that, for all plaza configurations simulated with the manual lanes operating over capacity, if only as little as 10% of the manual users switch to ETC lanes, then the total plaza delay (vehicle-hours) is cut in half, the average queuing delay per vehicle is reduced by more than 90 s, and the peak hour plaza throughput (vph) is increased by more than 20%. When the manual lanes operate under capacity, the increase in ETC usage has no impact on plaza delay or throughput. This study demonstrated that ETC vehicles' accessibility to the dedicated ETC lane(s) from the approach lanes could have a major impact on deciding the location of the dedicated ETC lane(s) within the toll plaza.     

Trajectories in operating a handheld tool.

The authors studied the trajectories of the hand and of the tip of a handheld sliding first-order lever in aiming movements. With this kind of tool, straight trajectories of the hand are generally associated with curved trajectories of the tip of the lever and vice versa. Trajectories of the tip of the lever exhibited smaller deviations from straight paths than did trajectories of the hand, even though the cursor, which displayed the position of the tip of the lever on a computer monitor, was invisible during movement execution. These observations suggest that movement of the effective part of the tool is the primary kinematic variable in motor planning and control, even in the absence of continuous visual feedback. The presence of continuous visual feedback did not change the basic pattern of results, except that the remaining deviations from straight paths of the tip of the lever became smaller. These deviations most likely result from an inertial anisotropy of the tool, and they are reduced by visually based online corrections. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of the Müller-Lyer illusion on the planning and control of manual aiming movements.

Two experiments used Müller-Lyer stimuli to test the predictions of the planning-control model (S. Glover, 2002) for aiming movements. In Experiment 1, participants aimed to stimuli that either remained the same or changed upon movement initiation. Experiment 2 was identical except that the duration of visual feedback for online control was manipulated. The authors found that the figures visible during movement planning and online control had additive effects on endpoint bias, even when participants had ample time to use visual feedback to modify their movements (Experiment 2). These findings are problematic not only for the planning-control model but also for A. D. Milner and M. A. Goodale's (1995) two visual system explanation of illusory bias. Although our results are consistent with the idea that a single representation is used for perception, movement planning, and online control (e.g., V. H. Franz, 2001), other work from our laboratory and elsewhere suggests that the manner in which space is coded depends on constraints associated with the specific task, such as the visual cues available to the performer. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

渣包车液压转向系统故障分析及排除

主要阐述了K350SH60型基律纳卡车也就是渣包车的基本构造,液压转向系统的工作原理、介绍了液压转向系统的故障现象、以及转向系统常见故障现象的原因分析与诊断方法。并对液压转向系统的主转向回路、事故转向回路、拖车转向回路、分别进行阐述。针对液压转向系统工作油路进行分析,对故障实例进行排除的一些措施。     

Feedback analysis of learning and performance in steering and tracking behavior.

Tested the assumption that steering and tracking behavior are interrelated in terms of the extent of self-produced stimulation involved in the 2 tasks. Steering was defined as involving maximal, and stimulus tracking as involving minimal levels of movement-regulated sensory information. 3 tasks steering, as governed by breath-produced target movement, stimulus tracking, and a hand-yoked target control task were compared under conditions in which the difficulty of the steering and stimulus tracking tasks were exactly equated. Results show that steering performance was more accurate and learned more rapidly than stimulus tracking. Oscillograph records of all aspects of performance indicate that the 2 tasks differed psychophysiologically in terms of how the self-timed respiratory activities and the external manual-visual responses were continuously and dynamically interrelated to control visual input. Results suggest that the modes and conditions of feedback control of dynamic sensory input not only determine accuracy of performance and rate of learning, but also define how internally-timed organic functions are integrated to determine learning in motor skills and other activities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)