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201.
针对基于深度学习的分类模型在训练样本较少时所遭受的潜在过拟合问题,提出一种具备过拟合抑制的生成式对抗网络分类算法,并应用于高光谱图像分类.该算法在每次迭代时,首先,依据训练样本的标签信息使判别器网络拟合训练样本的数据分布;然后对训练样本的高维特征进行均值最小化,该过程会重新更新判别器网络参数,减小参数的值和方差,以抑制... 相似文献
202.
NOBIAS PA1螯合树脂富集——ICP-MS定量测定近海水体中的稀土元素 总被引:1,自引:0,他引:1
稀土元素是海洋中一类极为重要的地球化学过程的示踪剂,但因其浓度多在pmol/kg数量级,分析测试一直是难点,为了使稀土元素在海洋研究中得到更广泛的应用,必须对海洋中低浓度的稀土元素进行准确测量。本研究建立了NOBIAS PA1螯合树脂富集—ICP-MS法,可以对近海的小体积水样中的稀土元素进行高准确度、高精密度分析。研究表明,调节样品溶液pH为4.59~4.69、清洗溶液为6 mL 0.05 mol/L NH_4AC、洗脱溶液为2 mL 1 mol/L HNO_3时,实验测试条件为最优。本方法对稀土元素的回收率在94%~106%,检出限范围为0.001~0.424 pmol/kg,分析精密度优于5%(n=5)。本研究所建立的方法,可用于河水、海水与河口盐度梯度区稀土元素的分析。 相似文献
203.
RD Hodgkiss A Grant JHR McClelland R Quatre B Rademakers C Sanchez 《African Journal of Marine Science》2017,39(2):225-232
This study produced the first data on population parameters for sicklefin lemon shark Negaprion acutidens at the granitic Seychelles Islands, adding to a limited catalogue of species information. Juveniles at a site in the Curieuse Marine National Park were tagged over two periods, in 2014–2015 and 2015–2016, with measurements of length (precaudal, fork and total) and weight, sex, and state of the umbilical opening recorded. Recapture data were used to calculate growth rates and population size. Mean annual growth rate was 5.40 cm y–1. A mean size at birth of 62.5 cm TL is in line with previous assessments of the species. Population-size estimates were similar for the two sampling periods (comprising 311 and 255 individuals) and higher than anticipated. Movements to outside the lagoon were recorded for early ages, and this, combined with weight loss and a reduction in condition factor as displayed in several individuals, suggests that the study area alone could not support the large number of sharks pupped yearly. 相似文献
204.
公共自行车系统是待开发的交通自愿碳减排项目。本文采用CCER方法学中的“快速公交项目”,计算北京市2012年公共自行车系统自愿碳减排量,并估算收益。结果显示:北京市2012年公共自行车自愿碳减排量为43.95 t CO2,出售可获得1538元的收益。同时估算得到北京市2015年公共自行车碳减排量为6874.5 t CO2,出售可获得约24万的收益。因此,北京等交通需求膨胀的特大型城市,随着公共自行车系统的持续壮大发展,公共自行车运营企业的经济效益有望通过碳交易实现较大提升空间。 相似文献
205.
A notable swarm occurred in Rushan, Shandong Peninsula and its activities continue since Oct. 2013 till now. Up to Sept. 30, 2014, more than 7 000 events have been recorded, in which locatable shocks exceed 2000, and 18 events with ML≥3.0. The swarm is rarely seen in East China for its extraordinary duration time and surprising high frequency of aftershocks. 18 temporary seismometers have been deployed around the swarm since May 6, 2014, and composed a seismic array for monitoring the swarm activities. Based on data from permanent networks and temporary array, we relocated the earthquake sequence by using hypoDD method. It has been shown that, there is obvious difference between permanent network results and temporary array results. The permanent network of Shandong has a relative large coverage gap(more than 200°)for this swarm. Its location results therefore should not be reliable. There are maybe other errors in the permanent network result due to some problems in the raw data, such as too few stations for most locatable events(3 stations), and relative lower proportion of located events in final result(74.3%, while 95.1% in temporary array result). It can be found by comparing location results from permanent network and temporary array that, using temporary array's data can improve the location accuracy significantly. The results of temporary array are: aftershocks distribution of Rushan swarm is in NWW direction, the dip-direction of fitted fault plane is SW, and the strike and dip angle agree with focal mechanism of the mainshock. Focal depths of aftershocks are at 4.5~8km; the swarm is restricted in a small area about 3km×3km×1km, and has some characteristics such as clustering, staged activities, and etc; the aftershock activities are in accord with crack growth behavior pattern, hence we deduced that there may be fluid intrusion in source area. Finally, we discussed the seismogenic structures and active mechanisms of this swarm combined with relative geologic knowledge. We draw some conclusions as follows: 1)Rushan swarm probably occurred at the boundary of rock bodies of Duogu Mountain and Haiyangsuo super-unit; 2)The seismogenic structure is a blind fault, which should be a part of adjacent Heishankuang-Jilincun Fault, or might be a new fault at rock body boundaries; 3)Rushan swarm might be an evidence for the existence of the disputed Shidao Fault. 相似文献
206.
207.
利用精确定位余震资料确定2014年云南鲁甸6.5级地震的断层面参数 总被引:1,自引:0,他引:1
运用双差定位法对2014年云南鲁甸6.5级地震序列余震进行重新定位,得到565次小震的精确定位结果.根据小震丛集性原则,求解发震断层参数的数学模型,运用模拟退火全局搜索和高斯牛顿局部搜索相结合的方法对地震发震断层面参数进行反演,得到鲁甸6.5级地震断层面的走向、倾角分别为160.8°和89.1°,并对其构造环境进行了分析. 相似文献
208.
209.
GPS基线快速计算与跟踪方法探讨 总被引:1,自引:0,他引:1
为减少中国地壳运动观测网络提供的GPS最终解的滞后时间,及时跟踪地壳形变的动态,利用提取的GPS长期运动背景外推GPS每日最终解;同时以松弛解H文件中的协方差矩阵为约束条件,对松弛解H文件中的坐标进行7参数转换,得到ITRF2000框架下的GPS当日坐标;用外推的GPS当日解、GPS最终解和H文件分别计算基线长,并对结果进行比较,然后,为了从大量的基线中找出变化幅度较大的基线,利用经验正交函数分析(EOF)方法对活动地块内基线的空间特征进行分析,实现对GPS基线的动态跟踪与监视。 相似文献
210.
A baseline might be used as a point of reference to monitor change from some specific data without concern for whether the
baseline determination is natural or has been changed by human activity. We selected 326 sediment samples from Dexing area,
South China, and analyzed for 17 chemical elements. The geochemical baseline was predicted with the method of the normalization
procedure combined with the relative cumulative frequency curve. The results indicate Al was the best reference element for
the normalization procedure among four potential reference elements (Al, Fe, Ti, and Mn). The baseline value range obtained
from the normalization procedure method included both the regional geochemical background of the sediment and the median value
of the measured contents. The median value of baselines obtained from relative cumulative frequency method was lower than
that obtained from normalization procedure method. In contrast to the geochemical patterns of heavy metals in 1987, the spatial
distribution of anomalies sprawled in 2004 in study area, especially for Cu, Pb, Zn, Cd, As, Fe, and Cr. 相似文献