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81.
Although sensory and emotional evaluation of food products mostly occurs in a controlled laboratory environment, it is often criticized as it may not reflect a realistic situation for consumers. Moreover, products are mainly blind evaluated by participants, whereas external factors such as brand are often considered as key drivers of food choice. This study aims to examine the role of research setting (central location test versus home-use test) and brand information on the overall acceptance, and sensory and emotional profiling of 5 strawberry-flavored yogurts. Thereby, private label and premium brands are compared under 3 conditions: blind, expected, and informed (brand information). A total of 99 adult subjects participated in 3 sessions over 3 consecutive weeks. Results showed that overall liking for 2 yogurt samples was higher in the laboratory environment under the informed evaluation condition, whereas no effect of research setting was found under the blind and expected conditions. Although emotional profiles of the products differed depending on the research setting, this was less the case for the sensory profiles. Furthermore, brand information clearly affected the sensory perception of certain attributes but had less influence on overall liking and emotional profiling. These results indicate that both scientists and food companies should consider the effect of the chosen methodology on ecological validity when conducting sensory research with consumers because the laboratory context could lead to a more positive evaluation compared with a home-use test.  相似文献   
82.
《Ergonomics》2012,55(10):1419-1438
Abstract

This paper presents two experiments in which steering a lane-change manoeuvre is analysed as a precognitive control task. The suggestion that the dependence on instantaneous visual feedback is low during such a task was tested by analysing steering performance under conditions both with and without visual occlusion. Steering force served as the main independent variable in experiment I, which was performed in a fixed-base driving simulator. A 1 s visual occlusion period during the initial steering-wheel movement to the left was given every other manoeuvre. The results indicate that steering force reduces steering-wheel amplitude variability, this effect also being reflected in the maximum heading angle variability.

Steering-wheel angle amplitude was the main independent variable in experiment II, which was carried out in the instrumented car. In this experiment the duration of the occlusion period was 3 s, i.e. covering the complete pull-out phase of the manoeuvre. The results show that variability in steering-wheel movement amplitude increases about linearly with the amplitude: standard deviations are about 9% of the amplitude. For both experiments I and II the results correspond quite well with those of an earlier reproduction experiment. Regarding the withdrawal of visual feedback it appears that occlusion affects the mutual tuning of steering amplitude and timing, rather than affecting these quantities separately. The vehicle-motion effects resulting from occlusion are relatively small and it can be concluded therefore that a temporary withdrawal of visual feedback has no dramatic effects in the pre-programmed task considered here.  相似文献   
83.
The chest response of the human body has been studied for several load conditions, but is not well known in the case of steering wheel rim-to-chest impact in heavy goods vehicle frontal collisions. The aim of this study was to determine the response of the human chest in a set of simulated steering wheel impacts. PMHS tests were carried out and analysed. The steering wheel load pattern was represented by a rigid pendulum with a straight bar-shaped front. A crash test dummy chest calibration pendulum was utilised for comparison. In this study, a set of rigid bar impacts were directed at various heights of the chest, spanning approximately 120 mm around the fourth intercostal space. The impact energy was set below a level estimated to cause rib fracture. The analysed results consist of responses, evaluated with respect to differences in the impacting shape and impact heights on compression and viscous criteria chest injury responses. The results showed that the bar impacts consistently produced lesser scaled chest compressions than the hub; the Middle bar responses were around 90% of the hub responses. A superior bar impact provided lesser chest compression; the average response was 86% of the Middle bar response. For inferior bar impacts, the chest compression response was 116% of the chest compression in the middle. The damping properties of the chest caused the compression to decrease in the high speed bar impacts to 88% of that in low speed impacts. From the analysis it could be concluded that the bar impact shape provides lower chest criteria responses compared to the hub. Further, the bar responses are dependent on the impact location of the chest. Inertial and viscous effects of the upper body affect the responses. The results can be used to assess the responses of human substitutes such as anthropomorphic test devices and finite element human body models, which will benefit the development process of heavy goods vehicle safety systems.  相似文献   
84.
Efficient driver drowsiness detection at moderate levels of drowsiness   总被引:1,自引:0,他引:1  
Previous research on driver drowsiness detection has focused primarily on lane deviation metrics and high levels of fatigue. The present research sought to develop a method for detecting driver drowsiness at more moderate levels of fatigue, well before accident risk is imminent. Eighty-seven different driver drowsiness detection metrics proposed in the literature were evaluated in two simulated shift work studies with high-fidelity simulator driving in a controlled laboratory environment. Twenty-nine participants were subjected to a night shift condition, which resulted in moderate levels of fatigue; 12 participants were in a day shift condition, which served as control. Ten simulated work days in the study design each included four 30-min driving sessions, during which participants drove a standardized scenario of rural highways. Ten straight and uneventful road segments in each driving session were designated to extract the 87 different driving metrics being evaluated. The dimensionality of the overall data set across all participants, all driving sessions and all road segments was reduced with principal component analysis, which revealed that there were two dominant dimensions: measures of steering wheel variability and measures of lateral lane position variability. The latter correlated most with an independent measure of fatigue, namely performance on a psychomotor vigilance test administered prior to each drive. We replicated our findings across eight curved road segments used for validation in each driving session. Furthermore, we showed that lateral lane position variability could be derived from measured changes in steering wheel angle through a transfer function, reflecting how steering wheel movements change vehicle heading in accordance with the forces acting on the vehicle and the road. This is important given that traditional video-based lane tracking technology is prone to data loss when lane markers are missing, when weather conditions are bad, or in darkness. Our research findings indicated that steering wheel variability provides a basis for developing a cost-effective and easy-to-install alternative technology for in-vehicle driver drowsiness detection at moderate levels of fatigue.  相似文献   
85.
The field of scientific workflow management systems has grown significantly as applications start using them successfully. In 2007, several active researchers in scientific workflow developments presented the challenges for the state of the art in workflow technologies at that time. Many issues have been addressed, but one of them named ‘dynamic workflows and user steering’ remains with many open problems despite the contributions presented in the recent years. This article surveys the early and current efforts in this topic and proposes a taxonomy to identify the main concepts related to addressing issues in dynamic steering of high performance computing (HPC) in scientific workflows. The main concepts are related to putting the human-in-the-loop of the workflow lifecycle, involving user support in real-time monitoring, notification, analysis and interference by adapting the workflow execution at runtime.  相似文献   
86.
采用非线性回归方程计算方法,结合实际生产的齿轮钢淬透性数据对数学模型进行修正。在此基础上,开发了齿轮钢淬透性的计算预报平台,实现根据成分和预设的晶粒度级别预报任意端淬距离的淬透性值。模型预测精度高于传统的多元线性回归方法。  相似文献   
87.
以CB/A14型内啮合齿轮泵为研究对象,详细讨论了该齿轮泵的齿轮结构特点,主要包括齿轮材质选择、结构确定和齿轮参数的选择。最后还介绍了CB/A14的流量脉动与密封情况。理论研究和实际应用表明,该泵承载能力大、效率高、工作噪声低,具有很好的发展前景。  相似文献   
88.
Governing project portfolios engages different actors in organizations including portfolio managers, portfolio officers, top managers, and others who may team up as portfolio steering committees. While portfolio steering committees play a regular role in project portfolio governance, their role is still unclear. Through an in-depth multiple case study in three Danish companies, the roles of portfolio steering committees were explored. The results showed that portfolio committees may play three distinct roles in portfolio governance: a) communication and consolidation role, b) negotiation role, and c) decision making role. The results challenged the notion that portfolio committee meetings are the place and time to make collective decisions on the portfolio, rather, portfolio steering committees might unintentionally become or intentionally be used for other purposes than decision making. The empirical evidence of the study proposes that these three roles might be related to two governance design factors: frequency and duration of committee meetings.  相似文献   
89.
As the thickness of crystalline silicon solar cells decreases, light loss cannot be avoided due to the absorption limit in long wavelength light. Internal rear side reflection can be enhanced by polishing the rear surface. The rear polishing processes are performed before the texturing and before and after doping the emitter layer to optimize the solar cell fabrication process sequences. All cells made by rear surface polishing showed improved light trapping in long wavelength region (900-1100 nm) compared to that in the conventional cells. However, silicon solar cells fabricated by rear polishing before and after doping have similar (35.5 mA/cm2) or lower (35.26 mA/cm2) short circuit current density compared to the cells produced by the conventional process (35.59 mA/cm2) due to pore damage to the anti-reflection layer and the surface of the emitter layer during rear polishing. This surface damage was effectively prevented adapting the rear surface polishing before the front surface texturing, which led to increasing the current density from 35.59 to 36.29 mA/cm2.  相似文献   
90.
对A380铝合金齿轮室失效件开裂部位显微组织、化学成分等进行分析,发现在产品两侧悬置区开裂部位存在缩松、缩孔、气孔、夹渣等铸造缺陷;利用有限元数值模拟软件分析产品在恶劣工况下的应力分布情况,显示在两侧悬置区应力集中,受力较大。认为铸造缺陷和应力集中的综合影响,是导致产品开裂失效的原因。通过改进浇注排气溢流系统、调整压铸工艺参数、优化产品结构设计等手段,产品开裂比例大幅度下降。  相似文献   
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