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281.
282.
讨论了国内基于人脸谱信息的信息安全技术研究总体现状 ,包括人脸谱信息的检测、定位、特征提取及主要识别方法和算法 ,并对各种方法的优点和问题进行了评述 ,最后对基于人脸谱信息的信息安全技术的应用前景进行了分析和预测。 相似文献
283.
Sigal Lahav Victoria Soroker Robert K. Vander Meer Abraham Hefetz 《Behavioral ecology and sociobiology》1998,43(3):203-212
This study compares two basic models for the origin and maintenance of colony gestalt odor in the polygynous ant species
Cataglyphis niger. In the first model, queens are centers of de novo biosynthesis and distribution of recognition odors (“queen-centered” model);
in the second, colony odors are primarily synthesized and distributed by workers (“worker-centered” model). We tested the
behavioral patterns that are predicted from each model, and verified by biochemical means the distributional directionality
of these signals. Encounters between nestmates originating from split colonies were as amicable as between nestmates from
non-split colonies; queenless ants were as aggressive as their queenright nestmates, and both were equally aggressed by alien
ants. These results indicate that queens have little impact on the recognition system of this species, and lend credence to
the worker-centered model. The queen-centered model predicts that unique queen substances should be produced in appreciable
quantities and that, in this respect, queens should be more metabolically active than workers. Analysis of the chemical composition
of postpharyngeal glands (PPGs) or cuticular extracts of queens and workers revealed high similarity. Quantitatively, queens
possessed significantly greater amounts of hydrocarbons in the PPG than workers, but the amount on the thoracic epicuticle
was the same. Queens, however, possess a lower hydrocarbon biosynthesis capability than workers. The biochemical evidence
thus refutes the queen-centered model and supports a worker-centered model. To elucidate the directionality of cue distribution,
we investigated exchange of hydrocarbons between the castes in dyadic or group encounters in which selective participants
were prelabeled. Queens tended to receive more and give less PPG content, whereas transfer to the epicuticle was low and similar
in all encounters, as predicted from the worker-centered hypothesis. In the group encounters, workers transferred, in most
cases, more hydrocarbons to the queen than to a worker. This slight preference for the queen is presumably amplified in a
whole colony and can explain their copious PPG content. We hypothesize that preferential transfer to the queen may reflect
selection to maintain her individual odor as close to the average colony odor as possible.
Received: 4 November 1997 / Accepted after revision: 5 February 1998 相似文献
284.
We provide evidence that male lizards can use chemosensory cues to identify individual females and probably therefore maintain
long-term associations with these females in the wild. In the laboratory, males preferentially followed the scent trail of
their vitellogenic female “partner” rather than that of another vitellogenic female. Our 5-year field study of the small viviparous
scincid lizard (Niveoscincus microlepidotus) in alpine Tasmania showed that sexually mature males and females commonly formed “pairs” for long periods (on average 29 days).
These pairs occurred primarily during the mating season, always involved one adult male and one adult female, and usually
involved vitellogenic rather than gravid females. Our laboratory experiments suggest that a significant factor in maintaining
those prolonged partnerships is male scent trailing of partners.
Received: 28 October 1997 / Accepted after revision: 28 May 1998 相似文献
285.
R. Shine 《Behavioral ecology and sociobiology》2005,57(6):591-598
Alternative sensory modalities (e.g. vision, chemoreception) differ in the spatial scale, permanence and reliability of cues they provide to mate-searching males. Males of terrestrial snake species use chemoreception to locate females over large distances, but phylogenetic shifts to aquatic life render such cues unavailable. Do male sea snakes use alternative modalities for identifying potential sexual partners and if so, are the novel systems as effective for mate-finding as the ancestral ones? Observations and experiments show that free-ranging male turtle-headed sea snakes (Emydocephalus annulatus) in shallow-water reef habitats in New Caledonia use visual cues (including size, movement and color pattern) to assess whether snake-shaped objects are potential sexual partners. Skin lipids (pheromones) are important only after the male comes into physical contact with the stimulus. Visual cues provide unreliable information about potential mates, and function over short distances only (generally, <1 m). In consequence, mate-searching male snakes frequently failed to find nearby females, rarely managed to maintain contact with females they did find, and wasted time and energy investigating inappropriate stimuli (e.g. fishes, sea cucumbers, divers). The loss of effective pheromonal mate-location systems means that mate recognition by aquatic snakes functions over smaller distances than in their terrestrial relatives. Phylogenetic transitions among habitat types thus may directly modify central features of the mating system. 相似文献
286.
采用物联网技术,设计一种由主控机PC、无线射频模块和读卡器模块等部分组成的起重机作业管理系统,实现人机互认及作业记录管理。详细介绍了系统硬件结构设计原理及实现方法,给出了作业管理系统软件设计。实际调试表明:该系统能够实现对作业人员身份的识别和起重机作业记录管理等功能,且具有数据传输有效距离远、移动性强、安装简单和扩展性好等特点。 相似文献
287.
矿柱是地下矿山支撑顶板围岩、维持采场稳定的关键结构要素。为迅速准确地判别矿柱稳定性,选取矿柱宽度、矿柱高度、矿柱宽高比、矿岩单轴抗压强度和矿柱承受载荷作为影响指标,利用高斯过程机器学习算法建立矿柱状态与其主要影响因素之间的非线性映射关系,进而提出一种基于高斯过程二元分类(GPC)的矿柱状态识别模型。结合工程实例,以40组样本数据进行训练,以10组样本数据对该模型进行检验,并与ANN和SVM进行对比。结果表明,矿柱状态识别的高斯过程模型是科学可行的,该模型具有参数自适应化获取、分类精度高、计算复杂度低等优点,还可对矿柱状态判别结果的不确定性或可信度进行定量化评价。 相似文献
288.
Experimental study on leak detection and location for gas pipeline based on acoustic method 总被引:5,自引:0,他引:5
Lingya MengLi Yuxing Wang WuchangFu Juntao 《Journal of Loss Prevention in the Process Industries》2012,25(1):90-102
The leak of gas pipelines can be detected and located by the acoustic method. The technologies of recognizing and extracting wave characteristics are summarized in details in this paper, which is to distinguish leaking and disturbing signals from time and frequency domain. A high-pressure and long distance leak test loop is designed and established by similarity analysis with field transmission pipelines. The acoustic signals collected by sensors are de-noised by wavelet transform to eliminate the background noises, and time-frequency analysis is used to analyze the characteristics of frequency domain. The conclusion can be drawn that most acoustic signals are concentrated on the ranges of 0-100 Hz. The acoustic signal recognition and extraction methods are verified and compared with others and it proves that the disturbing signals can be efficiently removed by the analysis of time and frequency domain, while the new characteristics of the accumulative value difference, mean value difference and peak value difference of signals in adjacent intervals can detect the leak effectively and decrease the false alarm rate significantly. The formula for leak location is modified with consideration of the influences of temperature and pressure. The positioning accuracy can be significantly improved with relative error between 0.01% and 1.37%. 相似文献
289.
基于面部特征识别的管制员疲劳监测方法研究 总被引:4,自引:0,他引:4
为进一步控制疲劳诱发的空管人为差错,提出一套基于面部特征识别的空中交通管制员疲劳实时监测方法。应用眼动仪和视频记录系统开展36 h睡眠剥夺试验,确定PERCLOS值、平均闭眼时长、哈欠频率3个疲劳判定指标的判定阈值,并给出综合疲劳程度的融合算法。应用机器视觉的理论和方法,开发功能完整的管制员疲劳状态实时监测告警原型系统。结果表明,通过对面部特征的识别和状态融合能够实现对管制员疲劳状态的实时监测。建议在此基础上进一步开发可实用的疲劳监测系统。 相似文献
290.
武玉梁 《中国安全生产科学技术》2012,(Z1):5-8
本文在分析国内煤矿井口安全监控系统的技术现状和矿井安全生产需求的基础上,结合四川中小煤矿企业的井口安全管理需要,提出了一种集人员考勤和危险源管理功能于一体的矿井出入口检控系统的设计方案。系统将活体指纹识别、视频技术与井口检控有机结合起来,实现出入井人员活体指纹考勤功能、对井下各地点安全隐患排查数据录入、分类整理、督促整改、隐患预警、查询、隐患打印、隐患复查等隐患治理控制功能,从根本上解决小煤矿管理不到位、技术人员缺乏、工作效率低等问题。加强了矿井安全管理力度,为安全隐患排查治理工作的规范、科学、高效提供了强有力保障。 相似文献