A Study on the Combined Effect of Noise and Vibration on Operators’ Performance of a Readability Task in a Mobile Driving Environment

This paper presents a study in which the main objective was to investigate the combined effect of noise and vibration on the performance of a readability task in a mobile driving environment. Subjects performed a readability task on a laptop computer in a sitting posture with their backs supported with a backrest under varying levels of noise and vibration. The data in terms of the mean number of characters read per minute were collected and statistically analyzed. Results showed that the individual effect of noise, vibration, and the operators’ gender as well as the interaction between gender and noise, and gender and vibration were statistically significant. However, the combined effect of noise and vibration was not found to be statistically significant. Results also indicated that gender was statistically significant at all levels of noise as well as vibration, and noise and vibration were statistically significant at both levels of gender.     

The effect of age on cognitive performance under the impact of vibration in a driving environment.

The effect of organismic variable age on human cognitive performance was studied under the impact of vibration in different automobile driving environments, namely city streets, rural roads and highways. Reaction time was measured in milliseconds through a human response measurement system specifically designed for the purpose. Results of the study showed that age had a significant effect in city street and rural road conditions. It was also found that the level of equivalent acceleration of vibration and a difficulty index significantly affected cognitive performance in all driving conditions. The organismic variable age observed to have a significant effect on task performance implied that youngsters and older people are stressed differently in specific environments of driving so proper stress management strategies should be evolved for them in order to minimize the number of accidents.     

某铅锌矿爆破有害效应分析及安全评估

以某铅锌矿爆破施工为背景,在现场试验的基础上,对测得的振动速度进行回归分析,得到场地爆破振动衰减规律,并结合爆破主频率,确定了周围民房的容许振动速度为2cm/s。同时,对爆破冲击波和噪声进行研究,结果表明:爆破振动、冲击波和噪声均与爆心距、炸药量有关。当爆心距相同时,噪声对建筑物和人员的影响最大,空气冲击波次之,爆破振动较小。主要从控制最大段药量和爆源距安全原则考虑,提出了防爆破振动、噪声和冲击波及飞石的安全距离。另外,还提出了硐口悬挂3层麻袋、堵塞炮泥和控制起爆网络中段间微差等安全措施,并对有害效应进行评估,其结果对后续爆破设计和施工具有实用价值和指导意义。     

Effects of multitasking on operator performance using computational and auditory tasks

This study investigated the effects of multiple cognitive tasks on human performance. Twenty-four students at North Carolina A&;T State University participated in the study. The primary task was auditory signal change perception and the secondary task was a computational task. Results showed that participants' performance in a single task was statistically significantly different from their performance in combined tasks: (a) algebra problems (algebra problem primary and auditory perception secondary); (b) auditory perception tasks (auditory perception primary and algebra problems secondary); and (c) mean false-alarm score in auditory perception (auditory detection primary and algebra problems secondary). Using signal detection theory (SDT), participants' performance measured in terms of sensitivity was calculated as ?0.54 for combined tasks (algebra problems the primary task) and ?0.53 auditory perceptions the primary task. During auditory perception tasks alone, SDT was found to be 2.51. Performance was 83% in a single task compared to 17% when combined tasks.     

The comparative merits of expert observation,subjective and objective data in determining the effects of in-vehicle information systems on driving performance

In this paper we report the results of a field study conducted for the EU project HASTE, in which the effect of IVIS task difficulty on driving performance was assessed by three concurrent methods. These included objective vehicle-related measures, subjective ratings from drivers and expert observers’ evaluations. Results showed that all three techniques were sensitive to detecting the effect of IVIS task difficulty on driving performance. As well as demonstrating a promising technique for measuring the effect of varying levels of visual spatial IVIS task on driving performance, this study highlights the value of subjective ratings and observer evaluation in assessing the effect of IVIS on driving performance.     

The moderating role of task characteristics in determining responses to a stressful work simulation

Two experimental studies were conducted to examine whether the stress‐buffering effects of behavioral control on work task responses varied as a function of procedural information. Study 1 manipulated low and high levels of task demands, behavioral control, and procedural information for 128 introductory psychology students completing an in‐basket activity. ANOVA procedures revealed a significant three‐way interaction among these variables in the prediction of subjective task performance and task satisfaction. It was found that procedural information buffered the negative effects of task demands on ratings of performance and satisfaction only under conditions of low behavioral control. This pattern of results suggests that procedural information may have a compensatory effect when the work environment is characterized by a combination of high task demands and low behavioral control. Study 2 (N=256) utilized simple and complex versions of the in‐basket activity to examine the extent to which the interactive relationship among task demands, behavioral control, and procedural information varied as a function of task complexity. There was further support for the stress‐buffering role of procedural information on work task responses under conditions of low behavioral control. This effect was, however, only present when the in‐basket activity was characterized by high task complexity, suggesting that the interactive relationship among these variables may depend on the type of tasks performed at work. Copyright © 1999 John Wiley & Sons, Ltd.     

The Effect of Protective Gloves on Manual Dexterity in the Cold Environments

This article presents a study on the effect of different protective gloves (which are commercially available and commonly used in the cold) on manual dexterity in cold environments. The experiments compared statistically four different types of gloves and two different types of gloving (outer or double) at +19 °C and -10 °C. Performance was determined both objectively and subjectively using two manual dexterity tasks: bolt-nut and pick-up tasks. The response measured was the time of performing each task. Statistical analysis showed that all independent factors such as glove type, participant, object size, and temperature had significant effects on the hand cooling reaction. A significant difference in the performance between the gloves was found in the bolt-nut task. It was also found that outer-inner combination gloving may be an approach to use for precision tasks.     

Ergonomic assessment of selected workstations on a merchant ship

This study describes some key ergonomic factors within the engine room, navigation bridge and other locations of a merchant ship. Ergonomic assessments were carried out on a crew of a merchant ship. The study examines the importance of factors such as noise, vibration, heat radiation (in machinery areas), psychological stress and ergonomics of the physical arrangement of the navigation bridge. It also addresses the effect of working in confined areas for a long duration and the need to process large amounts of data, decision-making and the influence of specific operating conditions in different areas of a ship. This study includes analysis of workstations, working methods and the burden of environmental factors as well as a discussion of specific marine environmental conditions such as confined working and leisure spaces, long-term family and sociocultural separation, frequent changes in climate and time zones, and temporary physical overload and long-term psychological burdens.     

过滤材料声学性能的实验研究*

为探讨纤维过滤材料的吸声效果,扩展吸声材料的选择范围,并为噪声粉尘一体化控制提供指导,通过实验分析不同等级一般通风用纤维层滤料的过滤性能和吸声性能,研究叠加方式及空腔设置等对滤料吸声性能的影响。研究结果表明:一定条件下,滤料的过滤效率越高吸声性能越好;单层滤料吸声效果较差,通过多层叠加,可显著提升吸声效果,达到吸声材料水平;不同等级滤料组合叠加,按过滤效率降序排列整体吸声性能更好。滤料作为吸声材料应用时,在其后侧设置空腔可明显增强吸声效果;兼顾过滤和降噪时,考虑粗效对中效滤料的保护作用,可在粗效加中效滤料后再附加粗效滤料,达到在不显著增加阻力的同时改善吸声性能的目标。     

大跨度公路隧道洞口段爆破对高边坡安全影响研究

为研究大断面公路隧道洞口段爆破开挖对边坡稳定性的影响，以某公路隧道洞口段工程为研究背景，基于Abaqus有限元软件，建立隧道—边坡三维数值计算模型，研究隧道洞口段爆破开挖对两侧高边坡安全性的影响，并分析砂浆锚杆对边坡的加固效果。结果表明:隧道洞口段爆破开挖施工时边坡坡脚处围岩振速最大，爆破对边坡水平振速影响较竖向振速及轴向振速更为显著，爆破时应控制坡脚及坡肩的水平振速；边坡坡面最大振速出现在洞口边坡坡面与仰坡坡面交线位置，边坡坡面与仰坡坡面交线上顶点为坡肩振速最危险的特征点，下端点为坡面振速最危险的特征点；增加锚杆长度对边坡水平位移的控制效果较竖向位移更为显著，锚杆长度宜取14 m。研究结果可为类似工程提供理论借鉴。     

Investigation of crashes at pedestrian hybrid beacons: Results of a large-scale study in Arizona

Introduction: The pedestrian hybrid beacon (PHB) is a traffic control device used at pedestrian crossings. A recent Arizona Department of Transportation research effort investigated changes in crashes for different severity levels and crash types (e.g., rear-end crashes) due to the PHB presence, as well as for crashes involving pedestrians and bicycles. Method: Two types of methodologies were used to evaluate the safety of PHBs: (a) an Empirical Bayes (EB) before-after study, and (b) a long-term cross-sectional observational study. For the EB before-after evaluation, the research team considered three reference groups: unsignalized intersections, signalized intersections, and both unsignalized and signalized intersections combined. Results: For the signalized and combined unsignalized and signalized intersection groups, all crash types considered showed statistically significant reductions in crashes (e.g., total crashes, fatal and injury crashes, rear-end crashes, fatal and injury rear-end crashes, angle crashes, fatal and injury angle crashes, pedestrian-related crashes, and fatal and injury pedestrian-related crashes). A cross-sectional study was conducted with a larger number of PHBs (186) to identify relationships between roadway characteristics and crashes at PHBs, especially with respect to the distance to an adjacent traffic control signal. The distance to an adjacent traffic signal was found to be significant only at the α = 0.1 level, and only for rear-end and fatal and injury rear-end crashes. Conclusions: This analysis represents the largest known study to date on the safety impacts of PHBs, along with a focus on how crossing and geometric characteristics affect crash patterns. The study showed the safety benefits of PHBs for both pedestrians and vehicles. Practical Applications: The findings from this study clearly support the installation of PHBs at midblock or intersection crossings, as well as at crossings on higher-speed roads.     

兰州市道路交通噪声污染与人体健康的分析

随着环保事业的发展,人们已认识到环境系统的健康与人体的健康状况有着密切的关系。笔者采用流行病学研究方法和SPSS 11.0forWindows的统计软件,对居住在交通干线两旁的居民,按照不同个体特征和不同居住环境所受交通噪声影响的程度进行了对比分析,其结果表明,中年人比老年人和青年人受噪声影响明显;不同性别受噪声影响程度没有明显差异;各功能区特征不同,混合区受噪声影响最严重;在道路交通噪声较高的区域,该地区居民的受影响程度也相对较高。最后,提出了在新城建设和旧城改造过程之中考虑城市道路规划设计,居民自身也应加强个人防护的防治对策     

Optimization of the levels of grip force,stroke rotation,frequency and grip span for a torqueing task

This study was to investigate the effects of grip force, frequency, stroke rotation and grip-span on discomfort and obtain best posture for hand tool users. Fifteen male participants volunteered in this study. Participants performed combined gripping with torqueing exertions for 5 min for two levels of frequency (10 and 20 exertions/min) at two levels of grip force (50 and 70 N), two levels of stroke rotation (30^○ and 60^○) and three levels of grip-span (4.7, 6 and 7.3 cm). Therefore, a 2×2×2×3 full factorial design was used. The analysis of variance (ANOVA) showed that frequency, stroke rotation and grip-span were significant on discomfort score. Minimum discomfort and comfortable posture was found to be 90 N grip force with 10 exertions/min for 60° stroke rotation at 6-cm grip-span. The grip force, frequency and stroke rotation were found significant on EMG activity of forearm muscles using multivariate analysis of variance (MANOVA). The extensor muscles were found more activated than flexor muscles during the given task.     

Investigating data entry task performance on a laptop under the impact of vibration: the effect of color.

The last 20 years have seen a tremendous growth in mobile computing and wireless communications and services. An experimental study was conducted to explore the effect of text/background color on a laptop computing system along with variable environmental vibration on operators' data entry task performance in moving automobiles. The operators' performance was measured in terms of the number of characters entered per minute without spaces (NCEPMWS) on a laptop computing system. The subjects were divided into 3 categories, namely, Novices, Intermediates and Experts. Findings suggest a re-evaluation of existing laptop designs taking ergonomics into consideration. It appears that proper selection of text/background color on the laptop coupled with controlled vehicular speed could result in a better quality of interaction between human and laptops and it could also resolve the problem of poor data entry task performance.     

城市轨道交通站台噪声测量研究

为研究城市轨道交通高架和地下站台噪声的规律和特点,选取某条线路中的3个高架站台以及3条线路中的7个地下站台进行实地测量,并对测量结果进行分析。研究结果表明:地下站台LAeq值都低于标准限值80 dB(A);站台的中心测点列车进站LAeq值和列车出站LAeq值都非常接近,使用T检验结果得出各站台中心测点列车进站LAeq值和列车出站LAeq值不存在显著差异（P>0.05）;站台测量时要考虑大客流带来的喧闹声;站台最大噪声值是列车出站时,位于站台列车车头停止位置。     

The role of situational factors in disciplinary judgements

This study examined the effects of four situational factors on the severity of punishment chosen by a manager following a rule infraction. Two attributes of the offender, gender and performance history, and two outcomes of the infraction, physical damage and personal injury, were combined within a scenario evaluated by 421 graduate business students in a 2 × 2 × 2 × 2 ANOVA design. Results indicated strong main effects for performance history, physical damage, and personal injury but not for gender. Further analyses indicated that the gender composition of the superior/offender dyad did not have a significant effect on the severity of discipline, although some variation occurred across dyads. These results imply that superiors are likely to base disciplinary judgements on situational factors, and that situational factors affect superiors' decisions in a simple, linear fashion.     

某大型机加车间数控机床减噪工程测试与分析研究

为研究大型机加车间噪声减噪工程现状效果和特点,选取某大型机加车间数控机床为研究对象,对其进行减噪工程治理,现场实测了治理前和治理后的噪声数据,并对噪声测量结果进行分析。研究结果表明:数控机床操作人员8 h连续等效A声级从治理前的89.2 dB(A),降到治理后的74.3 dB(A),降低了16.7%.;数控机床操作岗位位置测点,在加工1个机件的测量时间段里,噪声值从治理前的85.9 dB(A),降到治理后的55.1 dB(A),降低了33.85%;对机加车间现场布置了67个测点,在加工1个机件的测量时间段里进行测量,得到该车间噪声治理前和治理后噪声分布图;对数控机床减噪工程治理前和治理后的频谱进行了分析,得出治理前和治理后各自的最大声级所在频段不随距离的改变而改变,高频减噪效果显著。     

Comparison of Canadian firefighters and healthy controls based on submaximal fitness testing and strength considering age and gender

Introduction. Few studies have addressed whether firefighters are fitter than the general population and possess sufficient levels of aerobic capacity and muscle strength to perform on-duty tasks in a safe and efficient manner, considering age and gender. We aimed to evaluate the fitness levels of Hamilton firefighters, and to determine the effects of age and gender. Methods. In total, 89 participants were recruited. The modified Canadian aerobic fitness test was used to determine participants’ estimated maximal oxygen consumption (V_O2max) levels. For upper and lower body strength levels, a calibrated J-Tech hand-held dynamometer and a National Institute for Occupational Safety and Health (NIOSH) lifting device was used respectively. Results. Firefighters’ mean (SD) V_O2max level was 40.30?±?6.25?ml·kg^?1·min^?1. Age proved to have a statistically significant impact on V_O2max (p?<?0.001). Gender displayed statistically significant effects on strength levels. Firefighters’ age was the only statistically significant independent variable, and accounted for 61.00% of the variance in firefighters’ aerobic capacity levels. Conclusions. Firefighters possessed somewhat similar aerobic capacities but much higher levels of body strength when compared with the general population. With age, firefighters’ aerobic capacities decreased; however, their upper and lower body strength levels remained the same.     

Influence of task demands on occupational stress: Gender differences

IntroductionOccupational stress is a common phenomenon in our society, and generates problems for both workers' health and the functioning of organizations. Over past decades numerous studies have examined occupational stress from the perspective of gender, offering somewhat contradictory results. Some of them found no differences and others indicated that either men or women suffer from greater amounts of occupational stress.MethodThe purpose of this study was to analyze gender differences in stress in situations that involve certain occupational demands. The data used were taken from a random sample population of 11,054 (5,917 men and 5,137 women) from the VI National Survey on Working Conditions (NSWC) which was conducted in Spain in 2007. To carry out this study, a probabilistic model was constructed using Bayesian networks, with the following variables related to task demands: working with tight deadlines, quick work, intellectually demanding work, complicated tasks, repetitive tasks, excessive work, and work demanding high attention levels.ResultsThe results of this study reveal that: the indicators studied significantly increased stress levels; women initially had higher stress levels than men; and when exposed to determined task demands, stress differences between genders tended to increase.Impact on IndustryCompanies need to consider the gender of their workers when assigning tasks in high demand/stress jobs.     

Flicker Test as a Load Measurement During the Combined Effect of Heat and Noise

This study was a joint physiological and psychological experiment undertaken to determine changes in physiological and psychological human functions under the combined influence of heat, noise, and physical activity. Seven experimental situations were simulated in a climatic chamber with different configurations of three independent variables: heat (40 °C), noise (98 dB), and physical effort (30% of maximum volume of oxygen uptake—V0₂ max). Five psychological variables (critical flicker fusion—CFF, hand tremor, reaction time, subjective climate evaluation, and subjective evaluation of the given condition load) and two physiological variables (heart rate and rectal temperature) were monitored. Results indicate that CFF changed (increased) significantly when more than one experimental variable was applied. These changes coincided with significant changes in both subjective climate evaluation and subjective evaluation of a given condition load. There were no significant changes in psychomotor functions (hand tremor and reaction time). None of the observed physiological parameters were above the critical value. The results suggest that CFF can be treated as a psychophysical load indicator.