排序方式: 共有6条查询结果,搜索用时 15 毫秒
1
1.
William A. Watkins Mary Ann Daher Joseph E. George David Rodriguez 《Deep Sea Research Part I: Oceanographic Research Papers》2004,51(12):1889-1901
A unique whale call with 50–52 Hz emphasis from a single source has been tracked over 12 years in the central and eastern North Pacific. These calls, referred to as 52-Hz calls, were monitored and analyzed from acoustic data recorded by hydrophones of the US Navy Sound Surveillance System (SOSUS) and other arrays. The calls were noticed first in 1989, and have been detected and tracked since 1992. No other calls with similar characteristics have been identified in the acoustic data from any hydrophone system in the North Pacific basin. Only one series of these 52-Hz calls has been recorded at a time, with no call overlap, suggesting that a single whale produced the calls. The calls were recorded from August to February with most in December and January. The species producing these calls is unknown. The tracks of the 52-Hz whale were different each year, and varied in length from 708 to 11,062 km with travel speeds ranging from 0.7 to 3.8 km/h. Tracks included (A) meandering over short ranges, (B) predominantly west-to-east movement, and (C) mostly north-to-south travel. These tracks consistently appeared to be unrelated to the presence or movement of other whale species (blue, fin and humpback) monitored year-round with the same hydrophones. 相似文献
2.
近年来,我国多数地震动物观察站(SAOS)监测虎皮鹦鹉(BG=budegerigar)的叫声频度与地震的关系,并取得了一些观测结果。但是,所用的声记录仪未能考虑BG叫声的声学特性,而不能分辨BG不同的叫声和进一步提取震兆性叫声模式(EPCP),并易受到环境噪声的干扰而产生误计数。 据此,分析了BG不同声行为叫声的声学特性。BG叫声大致上可分为单次叫声(SC)、变音调叫声(VTC)、单音节和多音节抗议叫声(MoSPC和MuSPC)。由此,进一步研制了它们的模式识别系统。该系统是以单片机为核心的微处理机,对BG叫声进行预处理、编码、分析、显示和打印输出。 观察结果表明,在高声场旅游飞机噪声(TAN)干扰下,该系统的BG叫声识别率(CRR)为66.7%,而对TAN没有误计数。在含10次不同声强的TAN干扰(432秒)的30分钟内,该系统记录了588次叫声(SC、VTC、MoSPC和SPC分别为377、22、20和169次),仅丢失65次叫声,其CRR平均为90%。但是,SAOS目前使用的声记录仪,这10次TAN干扰所产生的误计数可能约为BGU叫声的2.6—13倍。 由此可见,这种模式识别系统不仅可满足于BG不同叫声的识别,且具有良好的抗噪声功能。这就使之可为地震前BG声行为观测提供更有用的信息。不仅可给出BG叫声频度的昼夜节律变化与地震的关系,并可为揭示BG的EPCP提供一定的依据。 相似文献
3.
Ko Ko Lwin Komei Sugiura Koji Zettsu 《International journal of geographical information science》2016,30(8):1579-1593
We can collect, store, and analyze a huge amount of information about human mobility and social interaction activities due to the emergence of information and communication technologies and location-enabled mobile devices under cyber physical system frameworks. The high spatial resolution of population data on a multi-temporal scale is required by transport planners, human geographers, social scientists, and emergency management teams. In this study, we build a space-time multiple regression model to estimate grid-based (500 m × 500 m) spatial resolution at multi-temporal scale (30-min intervals) population data based on the space-time relationship among geospatially enabled person trip (PT) survey data and incorporate both mobile call (MC) and geotagged Twitter (GT) data. Since using geospatially enabled PT survey data as dependent variables enables us to acquire actual population amounts, which strongly depend on MCs and social interaction activities. Although many grids have a strong correlation between PT and MC/GT, some show fewer correlation results, especially where the grids have factories, schools, and workshops in which fewer MCs are found but a large population is presented. Although GT data are sparser than MCs, people from amusement and tourist areas can be detected by GT data. The space-time multiple regression model can also estimate the different amounts of populations based on human travel behavior that changes over space and time. According to accuracy assessments, the night-time estimated results, especially between 00:00 and 06:30, strongly correlate with national census data except in places where the grids have railway and subway stations. 相似文献
4.
对汶川8级地震后群众咨询信息的分析及探讨 总被引:3,自引:0,他引:3
“5.12”四川汶川8.0级地震发生后,很多人打电话咨询有关情况,对5月12日至6月12日电话中的咨询信息进行了分析.就群众关心的地震问题、解答的效果以及暴露出的工作问题进行总结与分析,并提出一些建议。 相似文献
5.
6.
1