Texting and tapping : a dynamical approach to multitasking.

Jobs in various work fields (e.g., flying airplanes; Helmreich, 2000) require a high ability to successfully handle more than one task at a time, or to multitask. Researchers usually explain multitasking by having priorities in which individuals either attend to one task at a time, or one task receives more time processing than the other task. The current study approaches multitasking from a dynamical systems perspective. Fourteen general psychology students participated in the study by pressing a pedal attempting to maintain a steady beat and text messaging. Researchers recorded behavior over time (2 min. for each task and multitasking). The inputs to the data analysis were the X-Y coordinates of thumb movement (in pixels) over time and the recorded beat's deviation (in sec) from the metronome's beat over time. The patterns of behavior were recorded. Nonlinear analyses (Iterated Function Systems and a MANOVA on Hurst exponents for monofractality, and Wavelet Modulus Transform Maxima for multifractality) tested for fractal patterns which characterized both tasks in both conditions (single task or multitasking). Thumb movement's patterns during texting were not significantly different for single task and multitasking conditions, both displaying short-term correlations (brown noise). Patterns in tapping deviations were significantly different between the two conditions. Structure of deviations while only tapping was characterized by strong long-term correlations (pink noise); the structure while multitasking was also positively long-term correlated, but less strong. Results showed that texting and tapping behavior, as single tasks or during multitasking, are fractal

비만인의 발 도달 작업에 관한 인간공학 연구

학위논문(박사) -- 서울대학교대학원 : 공과대학 산업공학과, 2022. 8. 박우진.세계보건기구(World Health Organization)에 따르면, 비만이란 과도하게 신체에 지방이 축적된 물리적 상태로 정의된다. 비만을 정의하는 변수 중 널리 쓰이는 것으로 BMI(Body mass index)가 있으며, 체중을 키의 제곱으로 나눈 값으로 계산된다. BMI가 30 이상인 경우 비만으로 분류되고, 35 이상인 경우 고도비만으로 분류된다. 비만 인구는 매년 증가하는 추세로, WHO에 따르면 2016년 성인 중 19억명이 과체중(BMI 25 이상 30 이하)에 해당한다. 이 중 6억 5천만명이 비만으로 분류되어, 전체 성인 중 13%에 달한다. 2020년 기준 5세 이하의 아동 3900만명이 과체중이거나 비만인 것으로 추정되며, 3억 4천만명의 청소년 인구도 과체중이거나 비만으로 집계되고 있어 앞으로도 계속 비만인구는 증가할 것으로 예측되었다. 비만인구가 증가함에 따라 비만인 작업자의 비율도 꾸준히 증가하고 있으며, 결국 비만으로 발생하는 작업자의 능률 및 지각불편도에 대한 연구가 점점 더 필요한 실정이다. 많은 일상 생활과 작업활동에서 인간은 계속해서 육체적 과업 또는 자세를 유지하는 과업을 수행하고 있다. 따라서, 비만인들이 이런 육체적 과업을 수행할 때, 어떠한 양상을 보이는지에 대해 연구하는 것은 매우 중요하다고 할 수 있다. 기존 인간공학 연구에서 비만 관련 연구는 주로 자세 유지나 걷기 등과 같은 기초적인 것에 국한되어 있었다. 위에서 언급한 중요성에도 불구하고, 아직까지 일반적인 과업을 수행할 때, 비만이 신체적 능력 및 불편도에 어떠한 영향을 미치는지에 대한 연구는 미흡한 실정이다. 특히, 발 도달 작업 같은 기본적인 동작 같은 경우에도 비만의 영향을 알아본 연구는 전무하다. 따라서, 본 연구의 목적은 발 도달 작업에서 비만이 미치는 영향에 관해 파악하는 것이다. 이러한 연구 목적의 달성을 위해 크게 3가지 주요 연구가 수행되었다. 연구 1에서는 앉은 자세에서 발 도달 작업을 수행할 때 비만이 미치는 영향에 대해서 파악하였다. 비만인 그룹과 일반인 그룹을 모집하여 다양한 타겟의 위치 배치에 따른 발 도달 능력을 알아보았다. 실험 결과, 비만인 그룹과 일반인 그룹간 반응 시간, 이동 시간, 과업 수행 시간에 통계적으로 유의한 차이가 나타남을 확인할 수 있었다. 지각불편도는 비만인 그룹과 일반인 그룹간 유의한 차이가 나타나지 않았다. 연구 2에서는 연구 1의 확장으로 자세 요인을 추가적으로 넣어 실험을 수행하였다. 기존 연구 1의 데이터를 활용하여, 추가적인 비만인 모집을 수행한 후 데이터 수집을 진행하였다. 실험 분석 결과, 서 있는 자세에서도 앉은 자세와 마찬가지로 비만의 영향이 나타남을 확인할 수 있었다. 앉은 자세에서 먼 거리를 이동하는 발 도달 과업의 경우, 더 많은 이동 시간이 발생함을 알 수 있었다. 앉아 있는 자세에서 발 도달 과업을 수행할 때 지각불편도가 더 큰 값을 보임을 관측하였다. 연구 3에서는 연구1, 2의 결과 데이터를 통해 예측 발 도달 과업 범위를 제안하는 연구를 수행하였다. 기존 도달 범위 모델의 경우 대부분 손을 활용한 도달 범위를 제안하는 경우가 많았다. 일부 모델 생성 연구에서 최적 발 도달 범위를 제안하는 연구가 있었지만, 비만과 같은 인적 변수를 고려하지 않고 신체치수 등과 같은 변수만을 활용하였다. 본 연구의 데이터를 활용하여, 인적 요인에 따른 최적 발 도달 범위값을 제안하였다. 회귀분석을 통해 수행시간과 불편도에 대한 높은정확도의 예측추정식을 제안하였다. 앉은 자세일 때 수용될 수 있는 최대기준값이 더 작게 나타나는 것으로 보이며, 이를 고려한 발 도달 작업 가이드라인을 제시하였다. 본 연구의 결과를 통해 비만이 발 도달 과업에서 미치는 영향에 대한 이해를 향상시켰으며, 비만인 작업자들을 위해 최적의 발 도달 작업을 할 수 있는 작업장 설계에 도움이 되는 방법론을 제시하였다. 또한, 본 연구를 통해 기존 발 도달 작업 관련 인간공학 분야에 도움이 되는 지식을 제공할 수 있을 것으로 기대하고 있다. 비만이 발 도달 작업에 미치는 영향을 알 수 있게 되며, 발 도달 작업에서 발생하는 주관적 불편도에 대한 예측 모델을 생성할 때 비만요인과 작업자세를 적용할 수 있을 것으로 기대하고 있다. 또한 본 연구를 통해 실제 산업현장에서 비만인을 위한 작업 설계를 도와줄 수 있을 것이다. 추후 여성 작업자들의 발도달 작업 데이터를 수집하여 모든 작업자들에 대한 디지털 휴먼 모델링을 생성하는 것을 기대하고 있다. 비만인들의 부상 및 근골격계 질환 위험을 예방하여 경제적 이득을 가져올 수 있으며, 실제 비만인 작업자의 능률을 향상시켜 작업자의 사용자경험(UX) 개선에 도움이 될 것으로 기대하고 있다.Obesity is prevalent worldwide and the obese population continues to increase. Therefore, research is needed to find out the impacts of obesity in basic tasks, and, it could help with ergonomic design in the workplace. Existing ergonomic studies have examined the basic physical abilities of obese people, such as walking and balancing. Through an understanding of the physical capabilities of obese individuals, it is possible to design a workplace that is suitable for obese individuals. Foot reach work is a basic movement that occurs frequently in the workplace. In light of the results of ergonomic research related to obesity, it is possible that the foot reach task will exhibit a different result. Despite the importance mentioned above, understanding how obesity impacts physical performance and discomfort rating is still insufficient. Particularly, no studies have been found that have examined the effects of obesity on foot reach. Therefore, this study aims to investigate the impact of obesity on foot reach and develop a method to improve the performance of obese groups. To accomplish the objectives, three major studies were conducted. In the study 1, the impact of obesity was investigated in the foot target reach in a seated position. Task performance and discomfort rating data were analyzed. The differences between the participant groups (non-obese, obese) were compared statistically. It was found that the obese group had a statistical difference from the non-obese group in reaction time, movement time, and task completion time. In terms of discomfort rating, there was no significant difference between the obese and the non-obese group. In the study 2, the impact of obesity in standing posture was investigated as an expanding study of study 1. In the standing position, the movement time decreased, but the reaction time increased. There was no significant interaction effect between participant group and posture factors. Foot reach in a seated position was more uncomfortable. As a result of task performance time analysis, a significant interaction effect between posture and target distance was observed. In the study 3, a study was conducted to propose the prediction model. It describes the possible range of foot reach for workers using the existing prediction model. Task performance time data is used to present an area that optimizes the foot reach task of obese/non-obese workers. It was found that obese people have a smaller foot reach area. The above-mentioned findings investigate the impact of obesity on foot reach task and provide an understanding that helps design workplaces for obese people. Based on the findings from study 1, it was possible to understand how obesity affects foot reach in a seated position. The findings provided in the study 2 would be helpful to provide an understanding of the possible changes in performance in standing posture. The results of study 3 provide inspiration for workplace improvements for obese workers. For obese workers, it is possible to propose increasing the size of the target where the reduced foot reach performance is evident.Chapter 1 Introduction 1 1.1 Research Background 1 1.2 Research Objectives 3 1.3 Dissertation Outline 4 Chapter 2 Literature Review 7 2.1 Obesity Effects on Physical Function and Performance 7 2.2 Literature Review on Foot Target Reach Task 10 2.3 Literature Review on Reaction time 13 Chapter 3 Obesity Effects on Seated Foot Reaches 15 3.1 Introduction 15 3.2 Research Methods 17 3.3 Results 24 3.4 Discussions 29 Chapter 4 The effects of obesity and posture on foot reach tasks: task performance and perceived discomfort 37 4.1 Introduction 37 4.2 Research Methods 40 4.3 Results 45 4.4 Discussions 56 Chapter 5 Models for predicting standing and seated foot target reach movement times of obese and non-obese operators 66 5.1 Introduction 66 5.2 Research Methods 70 5.3 Results 74 5.4 Discussions 91 Chapter 6 Conclusion 95 6.1 Summary 95 6.2 Implications 97 6.3 Future Research Ideas 99 Bibliography 102 Appendix A. The ANOVA tables 123 A.1 The ANOVA results for reaction time 123 A.2 The ANOVA results for movement time 124 A.3 The ANOVA results for task performance time 125 A.4 The ANOVA results for discomfort rating 126 국문초록 130박

Biomechanical and Psychophysical Evaluation of Operating Loads in Vehicular Driving

The present paper proposes an evaluation method of operation loads in vehicular driving, such as the joint-load, the seat pressure, and the perceiving force, based on biomechanical and psychophysical evidences to assist the human-centered design of driving interfaces. The prototype simulator is developed by means of a big experimental data of human motor properties and force-perception properties related with driving operations. The usefulness of the proposed methodology is then demonstrated through a set of simulation experiments in the case of the curve traveling situation.2013 IEEE International Conference on Systems, Man, and Cybernetics, SMC 2013; Manchester; United Kingdom; 13 October 2013 through 16 October 201

Ergonomics in machine design : a case-study of the self-propelled combine harvester

7. 1. INTRODUCTIONMechanization not only changes the character and structure of labour in agriculture and industry, but also influences the nature of the work load. Instead of delivering energy, the main issue now is the perception and processing of information, as well as controlling and regulating the work being done by machines. More and more the accent is shifting to tasks which appeal to the capacity of man to process information.Supplying the requirements for increased capacity is possible by increasing the ground speed and/or the working width, which, however, involves higher information speed, more actions for operation per time unit and a higher operator's work load. Human beings should not adapt themselves to the machine and - as a consequence of too high a load - will hazard occupational diseases and reduced performance.By means of principles, parameters, procedures and criteria from various disciplines - anthropometry, perception, selection and action - ergonomics can contribute to an optimum man - task system with a high capacity and a favourable operator's load.This study deals with the ergonomic system-analysis of the operation of a self- propelled combine harvester. The operator of this machine regulates the movement - direction and speed -, the mowing and threshing, the separation of kernel and straw, as well as the delivery of the product. Based upon the information obtained from crop, terrain, plot and machine the operator has to decide on such an adjustment of the machine, which results in a process with a high capacity and a high quality of work.7.2. ANTHROPOMETRYThe characteristics of the human body determine the location and displacement of the operating controls, as well as the forces to be exerted, the nature and frequency of movements. Based upon the relevant measurements and motions of the human body, the anthropometric data are given for designing an optimum work- space lay-out of a combine harvester.1. Lay-out studiesTo determine the location and displacement of the controls, as well as the forces to be exerted, and the location of the foot-board and cutterbar, special measuring equipment and methods have been developed.The work-space lay-out - specific for each machine - appeared to differ considerably. It is recommendable, that frequently used controls are located close to each other and within the normal area.The forces needed for steering are very low, because of the application of power steering. The forces needed for operating the clutch and the brake-Pedal are too high for the older machines; for the newer combines they meet the requirements.2. FrequencyThe frequency with which different operations and movements have to be carried out, determines mainly the operator's work load. The data, collected in measuring the operation frequency, indicate the priority in the lay-out of controls.The studies show, that the header height, reel position and ground speed control are most important. The location and displacement of these controls deserve priority in the design of the work-space lay-out.The movements of the steering wheel only have a correcting character.3. M.T.M.-analysisBased upon the results of the lay-out studies and the frequency-analysis, the operating element time has been calculated by means of M.T.M.; these timevalues can be used to obtain reliable data of the ergonomic quality of the lay-out of a certain work-space.The study shows, that there are great differences between the various machines; a small modification in the work-space lay-out leads to a favourable change in the operating element time. A development in the direction of fingertip control - i.e. header height, reel position and ground speed control grouped together - is desirable.7.3. PERCEPTIONThe perception of information, that a worker receives from work-space and environment, takes place via the senses, which are sensitive to specific impulses. The reaction to the information depends upon the sense organ that is stimulated, the strength of the stimulus and the place where the stimulus arrives.1. SightThe perception of visual information depends upon the object, the environment and the distance between the eye and the object.For combining it is necessary to obtain information from the feed table auger just in front of the conveyor chain and of the separation from the previously cut swath. On the machines examined the visual angle, as well as the horizontal distance between the eye and the cutterbar, are favourable in the horizontal plane. In the vertical plane the view angle is extremely unfavourable; besides, the distance between the eye and the cutterbar is too long, which is caused by the large vertical distance.Improvement of the visibility is possible by reduction of the view angle and the vertical distance. The operator's platform must be brought closer to the field. An eccentric location of the operator's platform offers favourable possibilities, since the platform can be located next to the conveyor chain.2. HearingHearing ensures mutual communication between man, machine and environment. Depending on frequency, sound pressure level and duration of the exposure, sound has an annoying or a damaging effect.By the functioning of the engine and other parts of the machine, in particular: the threshing mechanism, the operators of combines are submitted to sound. Measured at the operator's ear, the sound pressure levels of the machines examined are too high, whilst the presence of a cabin does not lead to an important decline of the sound pressure level. Moreover, the ground speed during combining does not affect the sound pressure level.The most common method of solving the sound problem is the enclosure of the source to reduce the sound pressure level to bearable levels.3. Scent and tasteFrom an ergonomic point of view scent and taste are less important, because only a small number of actions appeals specifically to these senses. Attention must be paid to the dust in the air around an operator of a combine.The dust concentration in the air around operators of the machines examined is too high; with respect to the duration of the harvesting period the possibility of developing silicosis must be considered to be low. On a machine without cabin the dust concentration is considerably higher than on a machine with cabin; during harvesting barley less dust is circulating around the operator than during harvesting wheat.Protection of the operator of a combine against dust is possible by ventilation (blowing away or sucking off the particles) and personal protective equipment. The ideal concept is the enclosure of the operator in a cabin with a small overpressure, so that particles cannot penetrate into the work-space.4. FeelingBy uneveness of terrain and road surface, the profile of the tyres and the functioning of the engine and other parts of the machine, the operators of machinery are submitted to mechanical vibrations, which adversely affect their health and performance. The effect and impact of vibrations varies with the frequency, as the human body is most sensitive to mechanical vibrations within the frequency range from 2 Hz to 6 Hz. It is necessary, that the curve K = 4 of the VD1- Recommendation is not exceeded in designing the work-space of farm machinery.The intensity of mechanical vibrations on combine harvesters is low, whilst the movements in the vertical direction are more numerous than in the other directions. Combining at different ground speeds appears to affect hardly the intensity; with greater working width the intensity is slightly smaller. When driving on the road with increasing ground speeds there appears an increasing intensity, which is lower than during combining. The spectral distribution indicates the existence of specific frequency ranges, which are explicable from the machine.At present, the most obvious way to reduce ride vibration is to fit a correctly designed suspension seat. The benefit of a good suspension seat is limited by the increasing movements between the operator and the controls; to eliminate this the vibrations of the whole vehicle or the whole of the operator's work-space should be reduced. A suspended enclosed cabin - in which controls, seat and operator move simultaneously - is an approach, which combines the need for improving ride with greater protection from sound and dust.Since machines, performing functions of perception, do not exist or are very rare, the designer of a man-task system must take into account the attainments of the investigations regarding perception. For the combine this means primarily an adequate presentation of the relevant information; by improving the visibility of the cutterbar (reduction of the view angle and the vertical distance) this can be realized. Besides, the redundant and non-relevant information - sound, dust and mechanical vibrations - has to be eliminated; the suspended cabin - in which the controls, the seat and the operator move simultaneously - is an approach, which combines the need for improving ride with greater protection from sound and dust.7.4. SELECTIONThe transport of data from the stimulated sense organs ('input') to the effectors ('output') is not simply and solely transport. The data are processed, from the various possibilities the right answer is chosen ('choice') and transformed into action.1. TheoryIn task performance the number of directed switches from input to output determines information processing and mental load, because all signals make use of 'a single channel decision mechanism' with a limited capacity. Generally, a value of two to three bits per second is assumed to be the limit for adequate information processing.For the assessment of mental load a well-functioning parameter is not yet available; most can be expected of the method with dual tasks and the heart rate.2. Indoor experimentsFor studying a man-task system under controlled conditions and to obtain information regarding the ergonomic qualities of the work-space lay-out of a certain machine, a simulator is built.The studies led to the following conclusions:a. In simulating the operation of a combine harvester the performance and the load depend upon the experimental distraction and the anthropometric qualities of the work-space lay-out. The steering accuracy detiorates and the load increases as a function of the number of signals per minute in the secondary task. There is a significant difference between the machines, which increases as the experimental distraction increases.b. By executing an identical series of information a learning curve appears; the performance increases and the load decreases as a function of the number of cycles. The appearance of the learning curve is disturbed by different series of information in an experiment. There is a significant difference between the machines.In simulating the operation of a combine harvester, the performance and the load depend upon the experimental distraction (the number of signals per minute in the secondary task and the series of information in an experiment) and the anthropometric qualities of the work-space lay-out of the machine. The results of the indoor experiments confirm the statements - endorsed completely by the results of the M.T.M.-analysis -, that subjects are more quickly familiar with one machine than with another, which causes a more efficient performance.The conclusion can be made, that the performance and the load are primarily determined by the work-space lay-out.7.5. ACTIONThe choice of the decision mechanism is transported to the effectors and transformed into voluntary muscle movements, which are necessary for the output or performance of a man - task system.1. TheoryThe muscle movements demand energy and this leads to the physical load of man, whose working capacity is limited. Besides, the mechanical effect of human labour is very slight. An energy consumption of 20 kJ (= 4,8 kcal) per minute, including a basal metabolic rate of about 4,2 kJ (= 1 kcal) per minute, has been accepted as the maximum consistent level, that an adult man should be expected to expend.For the assessment of physical load well-functioning parameters are available. In all kinds of tasks, even over a long period of time, the heart rate can be faultlessly registered.2. Field experimentsFor collecting data about the character and extent of loading components during combining, as well as the influence they have on the output of the system, field experiments have been carried out.The studies led to the following conclusions:a. During the operation of a combine harvester the performance and the load depend upon the machine - in particular: the operator's platform-, the stubble height, the ground speed, the working width and the crop. There is a significant difference between the operator's platforms, which increases as the ground speed increases. The interaction between ground speed and working width, representing capacity, is significant; realizing a certain level of capacity, it is preferable to work at a low ground speed combined with a greater working width.b. Using an automatic header height control system the operation frequency and the load decrease. The advantage of an automatic system becomes greater when working at higher ground speeds.The results of the field experiments endorse completely the results of the anthropometric studies and the indoor experiments. There are differences between the machines; at an increasing information speed - indoor: increasing experimental distraction; field: increasing ground speed - the differences between the machines become greater.The conclusion can be repeated, that the performance and the load are primarily determined by the work-space lay-out.7.6. DISCUSSIONHuman beings should not adapt themselves to the machine and - as a consequence of too high a load - will hazard occupational diseases and reduced performance. By means of principles, parameters, procedures and criteria from various disciplines - Anthropometry (Chapter 2), Perception (Chapter 3), Selection (Chapter 4) and Action (Chapter 5) - the ergonomic factors, influencing the output or performance in operating a self-propelled combine harvester, have been studied by means of lay-out studies, indoor and field experiments. Based upon the results of these studies the conclusion can be made, that the performance and the load in a man-task system are primarily determined by the workspace lay-out. Recommendations for the ideal concept of the operator's platform of the self-propelled combine harvester are given (Chapter 6).Supplying the requirements for an increase of capacity it is necessary, that the designer of a self-propelled combine harvester pays attention to an adequate processing of the increasing information speed. This is possible by using machines with an optimum work-space lay-out and eliminating of redundant and non-relevant information. Moreover, the introduction of automation, in which many processes - combine: moving, mowing, threshing, cleaning and maintenance - are executed and corrected without human interference, offers favourable advantages.In the near future the 'supervisor of harvesting' has to settle - based upon the conditions of crop, terrain and climate - the norm and the tolerance of the whole process. Next to it, the supervisor has to control - sitting at home, in front of a correctly designed console - the processes and, if necessary, has to re-adjust by means of remote-control

The effects of sensory deprivation on sensory, perceptual, motor, cognitive, and physiological functions

Sensory deprivation effects on human sensory, perceptual, and physiological mechanism

Understanding Skill in EVA Mass Handling

This report describes the theoretical and operational foundations for our analysis of skill in extravehicular mass handling. A review of our research on postural control, human-environment interactions, and exploratory behavior in skill acquisition is used to motivate our analysis. This scientific material is presented within the context of operationally valid issues concerning extravehicular mass handling. We describe the development of meaningful empirical measures that are relevant to a special class of nested control systems: manual interactions between an individual and the substantial environment. These measures are incorporated into a unique empirical protocol implemented on NASA's principal mass handling simulator, the precision air-bearing floor, in order to evaluate skill in extravehicular mass handling. We discuss the components of such skill with reference to the relationship between postural configuration and controllability of an orbital replacement unit, the relationship between orbital replacement unit control and postural stability, the relationship between antecedent and consequent movements of an orbital replacement unit, and the relationship between antecedent and consequent postural movements. Finally, we describe our expectations regarding the operational relevance of the empirical results as it pertains to extravehicular activity tools, training, monitoring, and planning

Pattern of muscle contraction in car pedal control

Driver’s discomfort has gained a lot of attention, especially among interested parties. There are many interacting factors involving both the driver and the interior components of the car that contribute to discomfort while driving. In this study, an investigation was carried out on the contraction of the lower leg muscle among drivers when operating the accelerator pedal. The main objective of this study was to determine the pattern of muscle contraction when operating the accelerator pedal with regard to three different actions; pressing, half-pressing and releasing. Eleven participants were involved in this investigation into the muscle pattern, whereby surface electromyography (SEMG) was used to measure the activity of the lower leg muscle, known as the tibialis anterior (TA). The data collection procedure on the selected muscle was in accordance with the SEMG recommendations for the Non-Invasive Assessment of Muscles. Based on the results, the TA depicted that the highest muscle contraction occurred during the releasing action. In addition, there were significant differences between each action in the T-test analysis with p < 0.05. It can be concluded that the TA muscle works differently based on the car pedal actions

Understanding the Automotive Pedal Usage and Foot Movement Characteristics of Older Drivers

The purpose of this study was to understand the pedal usage characteristics of older drivers in various driving tasks using an instrumented vehicle. This study stemmed from the prevalence of the pedal application errors (PAEs) and the older drivers’overrepresentation in crashes caused by PAEs. With the population increasing and becoming older, it is estimated that in 2020 there will be 40 million drivers over the age of 65 in the United States. Compared with their younger counterparts, older drivers are facing declining cognitive and physical abilities, such as impaired vision, slower reaction time and diminishing range of limb motion. Because these abilities are closely associated both with the driving task and the ability to recover from a crash, older drivers are overrepresented in vehicle crash involvement rate, and they are especially vulnerable to injuries caused by the crashes. Pedal misapplication crash is a type of crash preceded by a driver mistakenly pressing the accelerator pedal. Recently, the National Highway Traffic Safety Administration issued a report on PAE. The report reveals that older drivers are overrepresented in pedal misapplication crashes and that several driving tasks are overrepresented, such as emergency stopping, parking lot maneuvers and reaching out of the vehicle to interact with a curb-side device such as a card reader, mailbox, or ATM. Existing research has investigated the PAEs from different perspectives, but questions remain as to why older drivers are more likely to commit PAEs in these driving tasks. The current study investigated the pedal usage characteristics of 26 older drivers in driving tasks, such as startle-braking, forward parking and reaching out from the vehicle, which are scenarios associated with higher risk of PAEs. Ten stopping tasks were also investigated as baseline tasks. The study was conducted on-road using an instrumented vehicle. The data collected by the instrumented vehicle included pedal travel (potentiometer), force applied on the pedals (Tekscan sensor), and video recordings of each driver’s upper body and his or her foot movement. The study findings include the following: a) There are significantly positive correlations between a driver’s stature and the percent of foot pivoting, as well as between the shoe length and the percent of foot pivoting, which means the taller the driver or the longer the driver’s shoe, the more likely the driver will use foot pivoting instead of foot lifting in the baseline stopping tasks; b) In the startle-braking task, the driver is more likely to use foot lifting than that in the baseline tasks; c) The foot movement strategy is not found to affect lateral foot placement in either the baseline stopping tasks or the startle-braking task; d) When reaching out of the driver’s window to swipe a card at a card reader, the lateral foot placement on the brake pedal will bias rightward, compared with the lateral foot placement prior to reaching out; e) Approaching a gated access or parking in a dark, relatively confined parking space does not significantly slow down a driver’ foot transfer from the accelerator pedal to the brake pedal; f) Stature of a driver does not significantly affect the time required to successfully complete a card-swiping task. A driver’s pedal operation characteristics are associated with many factors, among which four factors are identified to be relevant to the driver’s pedal operation: stature, shoe length, startle stimuli and reaching out of the driver’s window. To identify the direct causes of PAEs, future research should investigate the pedal operation characteristics in a more controlled environment. For example, an eye-tracking device can be used to study the relationship between gaze direction and foot movement. Other driving scenarios, such as reversing, should be studied as well. In addition, a study with a larger sample size and novice drivers is necessary to validate the findings of the current study and to understand the PAEs among the population with little driving experience. The current study has both clinical and engineering implications. For occupational therapists and driving rehabilitation specialists, factors such as stature, leg length, footwear, vehicle type and pedal configuration may provide information about driver’s foot behaviors. For example, drivers with flat-soled shoes may tend to use foot lifting and drivers with wedged shoes may tend to use foot pivoting. Drivers with very wide shoes may get the shoe caught under the brake pedal when pivoting from the accelerator pedal to the brake pedal. Drivers with short leg length may be able to use foot pivoting when driving a sports vehicle, but they would have to use foot lifting when driving a large truck. Drivers tend to use foot lifting when the pedals are higher above from the vehicle floor and drivers tend to use foot pivoting when the pedals are lower above the vehicle floor. An in-clinic test of a driver’s lower extremity functions prior to on-road assessment helps to select the appropriate test vehicles. For example, it is recommended that shorter drivers with weaker lower extremity functions use vehicles of which the pedals are lower above the vehicle floor. To reduce the chance of a driver’s foot slipping off the brake pedal, engineers should consider redesigning the pedal pad to increase the friction coefficient of shoe-pedal contact. For example, using tread width of 2mm produces higher friction values. In addition, Automatic Vehicle Identification can be implemented so that the drivers do not have to reach out of the window to swipe card and to enter a gated access. Other driver assistance systems such as Autonomous Emergency Braking and Automated Parking System can either mitigate the damage or eliminate the chance of a human error

Ergonomics of intelligent vehicle braking systems

The present thesis examines the quantitative characteristics of driver braking and pedal operation and discusses the implications for the design of braking support systems for vehicles. After the current status of the relevant research is presented through a literature review, three different methods are employed to examine driver braking microscopically, supplemented by a fourth method challenging the potential to apply the results in an adaptive brake assist system. First, thirty drivers drove an instrumented vehicle for a day each. Pedal inputs were constantly monitored through force, position sensors and a video camera. Results suggested a range of normal braking inputs in terms of brake-pedal force, initial brake-pedal displacement and throttle-release (throttle-off) rate. The inter-personal and intra-personal variability on the main variables was also prominent. [Continues.

Prevalence of haptic feedback in robot-mediated surgery : a systematic review of literature

© 2017 Springer-Verlag. This is a post-peer-review, pre-copyedit version of an article published in Journal of Robotic Surgery. The final authenticated version is available online at: https://doi.org/10.1007/s11701-017-0763-4With the successful uptake and inclusion of robotic systems in minimally invasive surgery and with the increasing application of robotic surgery (RS) in numerous surgical specialities worldwide, there is now a need to develop and enhance the technology further. One such improvement is the implementation and amalgamation of haptic feedback technology into RS which will permit the operating surgeon on the console to receive haptic information on the type of tissue being operated on. The main advantage of using this is to allow the operating surgeon to feel and control the amount of force applied to different tissues during surgery thus minimising the risk of tissue damage due to both the direct and indirect effects of excessive tissue force or tension being applied during RS. We performed a two-rater systematic review to identify the latest developments and potential avenues of improving technology in the application and implementation of haptic feedback technology to the operating surgeon on the console during RS. This review provides a summary of technological enhancements in RS, considering different stages of work, from proof of concept to cadaver tissue testing, surgery in animals, and finally real implementation in surgical practice. We identify that at the time of this review, while there is a unanimous agreement regarding need for haptic and tactile feedback, there are no solutions or products available that address this need. There is a scope and need for new developments in haptic augmentation for robot-mediated surgery with the aim of improving patient care and robotic surgical technology further.Peer reviewe