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21.
《Ergonomics》2012,55(8):583-602
Previous research using punctuate reaction time and counting tasks has found that the startle eyeblink reflex is sensitive to attentional demands. The present experiment explored whether startle eyeblink is also modulated during a complex continuous task and is sensitive to different levels of mental workload. Participants (N = 14) performed a visual horizontal tracking task either alone (single-task condition) or in combination with a visual gauge monitoring task (multiple-task condition) for three minutes. On some task trials, the startle eyeblink reflex was elicited by a noise burst. Results showed that startle eyeblink was attenuated during both tasks and that the attenuation was greater during the multiple-task condition than during the single-task condition. Subjective ratings, endogenous eyeblink rate, heart period, and heart period variability provided convergent validity of the workload manipulations. The findings suggest that the startle eyeblink is sensitive to the workload demands associated with a continuous visual task. The application of startle eyeblink modulation as a workload metric and the possibility that it may be diagnostic of workload demands in different stimulus modalities is discussed. 相似文献
22.
《Ergonomics》2012,55(12):1339-1349
This study presents the biological responses to shiftwork in two groups of workers with different shiftwork rotas. Biological responses were studied by recording the heart rate and the changes in the circadian profile of salivary cortisol over 24?h (RIA assays). Various items were recorded through questionnaires aimed at determining self appreciation of sleep quantity, stress, health, satisfaction at work and in private lives. Thirty two male subjects aged from 23 to 56, working for the same company, having given their informed consent, took part in the study. The study was carried out under realistic conditions (at the work place) under the control of an occupational physician. Sixteen day-workers (8 am?–?6?pm) served as a reference group. Eight shiftworkers included in alternate schedules (morning M 4 am?–?12 am, evening E 12 am?–?8?pm, night N 8?pm?–?4 am) according to a system M, S, N 3/2, (3 work, 2 rest) and eight according to a system 7/5 (3M/2S/2N/5R, 2/3/2/5, 2/2/3/5) constituted the groups of shiftworkers respectively named 3/2 and 7/5. All subjects had comparable ages and BMIs. Shiftworkers expressed a higher stress level and frequency of health problems and a lower satisfaction at work than the control. Among the three groups, the 7/5 group had the best health and fitness score and was in need of less sleep. Heart rate was not affected by shift work. Conversely, consistent changes appeared in cortisol circadian profiles, the greatest changes appearing for the night shift and among the two groups of shiftworkers, more particularly for the 7/5 group. These changes correlated with self-perceived constraints of work and showed the difficulties of adaptation to shiftwork. 相似文献
23.
周燕 《自动化与仪器仪表》2012,(3):80-81
介绍了一种基于单片机的矿用隔爆电动阀门控制器的系统设计,描述了系统的工作原理及功能,给出了系统的结构、硬件组成和软件设计情况。 相似文献
24.
In order to simplify the structure of the cold end of the pulse tube refrigerator (PTR) and have a better utilization of the cold energy of the system, a single stage four-valve pulse tube refrigerator (FVPTR) with a ‘L’ type pulse tube structure and two orifice valves at the hot end of pulse tube has been constructed. Verification experiments show that a two-orifice valve structure gives different adjustments to the gas flow rate of the hot end of the pulse tube than that of the one-orifice valve structure, a lowest temperature of 72 K was obtained at a frequency of 2.5 Hz under a system average pressure of 1.6 MPa with 200 mesh bronze screens as regenerator material, 20 mesh copper screens as stuffing material of heat exchanger. Due to the difficulty in manufacturing the thin ‘L’ type pulse tube, the wall thickness of the pulse tube in the experiment is relatively bigger than that of the ordinary pulse tube, which resulted in relatively big system loss and affected the minimum temperature of the system to a certain degree. 相似文献
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26.
An Advanced Loose Parts Monitoring System (its acronym is ALPS) has been developed and installed on each unit of the Paks Nuclear Power Plant, Hungary. ALPS uses sophisticated methods to identify the events hidden in the quite extensive background noise of nuclear power plants. A classification algorithm based on an expert system, which is trained during the start-up period of each fuel cycle, helps to improve the false alarm rate. Thus the false alarm rate was reduced to a minimum, statistically below 1%. In practice, even the remaining “false alarms” were identified to be originating from other noise sources using ALPS. The main principles of ALPS are presented. It is demonstrated, that even weak signals, comparable with the resolution of the analog-digital board, i.e. comparable with detection noises, can be identified at high certainty. Other events like vibration of the shaft of motor operated isolating valves have been identified by ALPS. Furthermore, experiences gained during the installation period are also discussed. 相似文献
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28.
U. Rajendra AcharyaAuthor VitaeP. Subbanna BhatAuthor Vitae S.S. IyengarAuthor Vitae Ashok RaoAuthor VitaeSumeet DuaAuthor Vitae 《Pattern recognition》2003,36(1):61-68
The electrocardiogram is a representative signal containing information about the condition of the heart. The shape and size of the P-QRS-T wave, the time intervals between its various peaks, etc. may contain useful information about the nature of disease afflicting the heart. However, these subtle details cannot be directly monitored by the human observer. Besides, since bio-signals are highly subjective, the symptoms may appear at random in the time scale. Therefore, the signal parameters, extracted and analysed using computers, are highly useful in diagnostics. This paper deals with the classification of certain diseases using artificial neural network (ANN) and fuzzy equivalence relations. The heart rate variability is used as the base signal from which certain parameters are extracted and presented to the ANN for classification. The same data is also used for fuzzy equivalence classifier. The feedforward architecture ANN classifier is seen to be correct in about 85% of the test cases, and the fuzzy classifier yields correct classification in over 90% of the cases. 相似文献
29.
为了给医生利用医学图象进行诊断和分析心血管疾病提供一个有效的工具和途径,利用计算机视觉中的正则化方法,结合心脏和心血管动态特征的临床知识,对两种医学动态图象(超声心动图和心血管造影图)进行了定量的运动分析,并完成了一套应用软件.实验结果证明,该方法明显优于以往的图象分析方法。 相似文献
30.
张佩勤 《沈阳理工大学学报》1997,16(4):25-29
论述了自动化立体仓库的基本原理、传动设计、载货台液压系统、行驶机构与总体布局的设计.堆垛机的各种运动由计算机控制管理,位置检测与定位精度是由绝对式编码器以二进制代码形式向系统传送数据来实现. 相似文献