A reliable chronology is essentially critical for correlating loess records with other paleoenvironmental time series, as well as for continuing improvements in the reconstruction of paleoenvironment and paleoclimate ...A reliable chronology is essentially critical for correlating loess records with other paleoenvironmental time series, as well as for continuing improvements in the reconstruction of paleoenvironment and paleoclimate changes. It is exactly that the scarcity of chronologies across the Sea of Azov has limited the interpretation of climatic and environmental information in the East European Plain. In view of this, this paper conducted an exploratory study to investigate whether the optically stimulated luminescence(OSL) dating of medium-grained quartz could be used to obtain a set of chronologies and the age models could be used to establish an independent time scale since the Late Pleistocene for the Sea of Azov loess. The results showed that an internally consistent set of optical ages for the Azov loess deposited up to ~76 ka. In addition, the ages developed based on magnetic susceptibility and grain size ages models showed good comparability with independent OSL ages at an acceptable range, suggesting that it might be practicable to establish an independent time scale using age models at the Sea of Azov loess, at least for the uppermost part of the Chumbur-Kosa section. Comparison with the ages based on two age models,the grain size ages using fine-grain fractions may provide a more reliable chronological sequence at the Azov loess since the Late Pleistocene. With the help of absolute ages and climate proxies(magnetic susceptibility and grain size), paleoclimatic change in the Sea of Azov have been traced for the Late Pleistocene.展开更多
Foreground detection is a fundamental step in visual surveillance.However,accurate foreground detection is still a challenging task especially in dynamic backgrounds.In this paper,we present a nonparametric approach t...Foreground detection is a fundamental step in visual surveillance.However,accurate foreground detection is still a challenging task especially in dynamic backgrounds.In this paper,we present a nonparametric approach to foreground detection in dynamic backgrounds.It uses a history of recently pixel values to estimate background model.Besides,the adaptive threshold and spatial coherence are introduced to enhance robustness against false detections.Experimental results indicate that our approach achieves better performance in dynamic backgrounds compared with several approaches.展开更多
In the process of accurate interpretation of multi-wave seismic data,we wanted to solve the problem of multi-wave information recognition.Based on techniques of elastic wave forwarding,targeting the geological model o...In the process of accurate interpretation of multi-wave seismic data,we wanted to solve the problem of multi-wave information recognition.Based on techniques of elastic wave forwarding,targeting the geological model of a reservoir of an oil field exploration area,we used a high-order staggered-grid difference technology to simulate many shots of seismic records of nonzero offset shots,implemented multi-wave seismic data processing to acquire the CMP of P waves and converted waves,NMO traces of CCP pre stacks,including AVA information and superposition profiles.Based on the AVA calculation of the model,the layer parameters of the model and the forwarding wave field relations of the P-S wave,we also compared and studied the correspondence between P waves and converted waves.The results of our analysis show that the results from simulation and from the AVO analysis are consistent.Significant wave field differences between P waves and converted waves in the same reservoir were found,which are helpful in recognizing and interpreting the multi-wave information in this area.We made use of the multi-wave data to provide the important guidelines for reservoir prediction.展开更多
In order to explore the mineral resources buried in sea mud,it is necessary to use seabed resistivity measuring equipment,which works closer to the sediments than ordinary ship-based geophysical measuring equipment. B...In order to explore the mineral resources buried in sea mud,it is necessary to use seabed resistivity measuring equipment,which works closer to the sediments than ordinary ship-based geophysical measuring equipment. Because of the harsh environment of seafloor,high pressure and highly conductive seawater,marine magnetotelluric method developed slowly. The sea floor environment is similar to the environment of logging, According to the design of dual lateral logging equipment,a new equipment for seafloor electrical resistivity measurement is designed. Four 3D FEM models that contain resistivity abnormal targets are built to test the ability of this equipment to locate different shape of shallow buried resistivity abnormal targets in sea mud. The authors propose the method to correct the response curve while the bottom surface of this equipment is suspended or not parallel to the seafloor. The resistivity of targets can be calculated accurately.展开更多
There are controversies on ground motion attenuation relations at the epicentral distance of about 100km. Some models predict that the seismic energy remains almost constant or becomes even stronger with increasing di...There are controversies on ground motion attenuation relations at the epicentral distance of about 100km. Some models predict that the seismic energy remains almost constant or becomes even stronger with increasing distance at this distance, while other models hold that it decreases with increased distance. The divergence lies mainly in whether SmS is stronger than direct S and surface waves at this distance. With the MsS. 9 earthquake sequence in the Yingjiang region of Yunnan Province as an example, we demonstrate that SmS is always 2 - 5 times stronger than direct S waves around the epicentral distance of 100km （which is the post-critical distance for S in this region）. Study of synthetic seismograms suggest that crustal structure has an important effect on the amplitude of post-critical SmS, with simple crust producing strong SmS. This preliminary study confirms that in China, SmS also plays an important role on ground motion at distances around 100km, which demands more studies of post-critical SmS.展开更多
When recording a hologram,we should control the exposure amount which is in nonlinear area of the characteristic curve of complex amplitude transmittance t-exposure H,the hologram can diffract some higher-order diffra...When recording a hologram,we should control the exposure amount which is in nonlinear area of the characteristic curve of complex amplitude transmittance t-exposure H,the hologram can diffract some higher-order diffracted photograph.The amount of diffracted order has something to do with the recording angle betweenobject beam and reference beam,is concerned with the ship of transmission curve.Theintensity distribution of the higher-order diffracted beam is modulated by the change of phase difference.If the phase difference increased a time,the number of diffracted fringes also increased a time,it is similar to a fringe multipler,that it is obvious to increase the precision of interferometry.Nonlinear recording of double exposure method is discussed,and the formula of intensity distribution of second order diffracted photography,and experimental results are given.展开更多
We start with a description of the statistical inferential framework and the duality between observed data and the true state of nature that underlies it. We demonstrate here that the usual testing of dueling hypothes...We start with a description of the statistical inferential framework and the duality between observed data and the true state of nature that underlies it. We demonstrate here that the usual testing of dueling hypotheses and the acceptance of one and the rejection of the other is a framework which can often be faulty when such inferences are applied to individual subjects. This follows from noting that the statistical inferential framework is predominantly based on conclusions drawn for aggregates and noting that what is true in the aggregate frequently does not hold for individuals, an ecological fallacy. Such a fallacy is usually seen as problematic when each data record represents aggregate statistics for counties or districts and not data for individuals. Here we demonstrate strong ecological fallacies even when using subject data. Inverted simulations, of trials rightly sized to detect meaningful differences, yielding a statistically significant p-value of 0.000001 （1 in a million） and associated with clinically meaningful differences between a hypothetical new therapy and a standard therapy, had a proportion of instances of subjects with standard therapy effect better than new therapy effects close to 30%. A ―winner take all‖ choice between two hypotheses may not be supported by statistically significant differences based on stochastic data. We also argue the incorrectness across many individuals of other summaries such as correlations, density estimates, standard deviations and predictions based on machine learning models. Despite artifacts we support the use of prospective clinical trials and careful unbiased model building as necessary first steps. In health care, high touch personalized care based on patient level data will remain relevant even as we adopt more high tech data-intensive personalized therapeutic strategies based on aggregates.展开更多
A modified Gauss-Markov model with weighted constraints was constructed by combining satellite altimeter and tide gauge records. Vertical motion rates of nine tide gauge stations around the Bohal Sea and Yellow Sea ar...A modified Gauss-Markov model with weighted constraints was constructed by combining satellite altimeter and tide gauge records. Vertical motion rates of nine tide gauge stations around the Bohal Sea and Yellow Sea are estimated. This is the first time systematic estimates have been derived in this region. Downward trends were seen at the six tide gauge stations located at Tanggu, Longkou, Laohutan, Bayuquan, Xiaochangshan, and Yantai; with vertical motion rates of-1.82±0.50, -1.65±0.46, -0.88±0.42, -0.58±0.62, -0.13±0.43, and -0.01±0.43 mm/yr, respectively. Upward trends were seen at the three tide gauge stations located at Qinhuangdao, Huludao and Chengshantou; with vertical motion rates of 1.12±0.46, 0.55±0.49 and 0.26±0.44 mm/yr, respectively. There was significant subsidence in Tanggu and Longkou, and a rising trend in Qinhuangdao. According to our results, the rate of sea level rise calculated from these tide gauge records can be improved using a more accurate measurement of the land elevation accounting for lifting or subsidence. The model derived can be used to estimate vertical motions of tide gauge stations, and can be widely applied to revise the benchmark levels of tide gauges.展开更多
基金auspices of the National Natural Science Foundation of China (Grant No. 41271024)the International Cooperation and Exchange Project (Grant No. 41411130204)the Fundamental Research Funds for the Central Universities (Grant No. lzujbky-2016-270)
文摘A reliable chronology is essentially critical for correlating loess records with other paleoenvironmental time series, as well as for continuing improvements in the reconstruction of paleoenvironment and paleoclimate changes. It is exactly that the scarcity of chronologies across the Sea of Azov has limited the interpretation of climatic and environmental information in the East European Plain. In view of this, this paper conducted an exploratory study to investigate whether the optically stimulated luminescence(OSL) dating of medium-grained quartz could be used to obtain a set of chronologies and the age models could be used to establish an independent time scale since the Late Pleistocene for the Sea of Azov loess. The results showed that an internally consistent set of optical ages for the Azov loess deposited up to ~76 ka. In addition, the ages developed based on magnetic susceptibility and grain size ages models showed good comparability with independent OSL ages at an acceptable range, suggesting that it might be practicable to establish an independent time scale using age models at the Sea of Azov loess, at least for the uppermost part of the Chumbur-Kosa section. Comparison with the ages based on two age models,the grain size ages using fine-grain fractions may provide a more reliable chronological sequence at the Azov loess since the Late Pleistocene. With the help of absolute ages and climate proxies(magnetic susceptibility and grain size), paleoclimatic change in the Sea of Azov have been traced for the Late Pleistocene.
基金supported by Fund of National Science & Technology monumental projects under Grants No.61105015,NO.61401239,NO.2012-364-641-209
文摘Foreground detection is a fundamental step in visual surveillance.However,accurate foreground detection is still a challenging task especially in dynamic backgrounds.In this paper,we present a nonparametric approach to foreground detection in dynamic backgrounds.It uses a history of recently pixel values to estimate background model.Besides,the adaptive threshold and spatial coherence are introduced to enhance robustness against false detections.Experimental results indicate that our approach achieves better performance in dynamic backgrounds compared with several approaches.
基金the Doctor Research Fund for Universities of China (No.20070616004)the National High Technology Research and Development Program of China (No.2007AA060505)
文摘In the process of accurate interpretation of multi-wave seismic data,we wanted to solve the problem of multi-wave information recognition.Based on techniques of elastic wave forwarding,targeting the geological model of a reservoir of an oil field exploration area,we used a high-order staggered-grid difference technology to simulate many shots of seismic records of nonzero offset shots,implemented multi-wave seismic data processing to acquire the CMP of P waves and converted waves,NMO traces of CCP pre stacks,including AVA information and superposition profiles.Based on the AVA calculation of the model,the layer parameters of the model and the forwarding wave field relations of the P-S wave,we also compared and studied the correspondence between P waves and converted waves.The results of our analysis show that the results from simulation and from the AVO analysis are consistent.Significant wave field differences between P waves and converted waves in the same reservoir were found,which are helpful in recognizing and interpreting the multi-wave information in this area.We made use of the multi-wave data to provide the important guidelines for reservoir prediction.
文摘In order to explore the mineral resources buried in sea mud,it is necessary to use seabed resistivity measuring equipment,which works closer to the sediments than ordinary ship-based geophysical measuring equipment. Because of the harsh environment of seafloor,high pressure and highly conductive seawater,marine magnetotelluric method developed slowly. The sea floor environment is similar to the environment of logging, According to the design of dual lateral logging equipment,a new equipment for seafloor electrical resistivity measurement is designed. Four 3D FEM models that contain resistivity abnormal targets are built to test the ability of this equipment to locate different shape of shallow buried resistivity abnormal targets in sea mud. The authors propose the method to correct the response curve while the bottom surface of this equipment is suspended or not parallel to the seafloor. The resistivity of targets can be calculated accurately.
基金sponsored by the Basic Scientific Research Specific Program (02092410),Institute of Earthquake Science,China Earthquake Administration
文摘There are controversies on ground motion attenuation relations at the epicentral distance of about 100km. Some models predict that the seismic energy remains almost constant or becomes even stronger with increasing distance at this distance, while other models hold that it decreases with increased distance. The divergence lies mainly in whether SmS is stronger than direct S and surface waves at this distance. With the MsS. 9 earthquake sequence in the Yingjiang region of Yunnan Province as an example, we demonstrate that SmS is always 2 - 5 times stronger than direct S waves around the epicentral distance of 100km （which is the post-critical distance for S in this region）. Study of synthetic seismograms suggest that crustal structure has an important effect on the amplitude of post-critical SmS, with simple crust producing strong SmS. This preliminary study confirms that in China, SmS also plays an important role on ground motion at distances around 100km, which demands more studies of post-critical SmS.
文摘When recording a hologram,we should control the exposure amount which is in nonlinear area of the characteristic curve of complex amplitude transmittance t-exposure H,the hologram can diffract some higher-order diffracted photograph.The amount of diffracted order has something to do with the recording angle betweenobject beam and reference beam,is concerned with the ship of transmission curve.Theintensity distribution of the higher-order diffracted beam is modulated by the change of phase difference.If the phase difference increased a time,the number of diffracted fringes also increased a time,it is similar to a fringe multipler,that it is obvious to increase the precision of interferometry.Nonlinear recording of double exposure method is discussed,and the formula of intensity distribution of second order diffracted photography,and experimental results are given.
文摘We start with a description of the statistical inferential framework and the duality between observed data and the true state of nature that underlies it. We demonstrate here that the usual testing of dueling hypotheses and the acceptance of one and the rejection of the other is a framework which can often be faulty when such inferences are applied to individual subjects. This follows from noting that the statistical inferential framework is predominantly based on conclusions drawn for aggregates and noting that what is true in the aggregate frequently does not hold for individuals, an ecological fallacy. Such a fallacy is usually seen as problematic when each data record represents aggregate statistics for counties or districts and not data for individuals. Here we demonstrate strong ecological fallacies even when using subject data. Inverted simulations, of trials rightly sized to detect meaningful differences, yielding a statistically significant p-value of 0.000001 （1 in a million） and associated with clinically meaningful differences between a hypothetical new therapy and a standard therapy, had a proportion of instances of subjects with standard therapy effect better than new therapy effects close to 30%. A ―winner take all‖ choice between two hypotheses may not be supported by statistically significant differences based on stochastic data. We also argue the incorrectness across many individuals of other summaries such as correlations, density estimates, standard deviations and predictions based on machine learning models. Despite artifacts we support the use of prospective clinical trials and careful unbiased model building as necessary first steps. In health care, high touch personalized care based on patient level data will remain relevant even as we adopt more high tech data-intensive personalized therapeutic strategies based on aggregates.
基金supported by the National Natural Science Foundation of China(Grant Nos.4140603241206021&41376014)+4 种基金the National Basic Research Program of China(Grant No.2012CB955601)the National Key Technology R&D Program of China(Grant No.2014BAB12B02)the Key Technology R&D Program of Tianjin(Grant No.14ZCZDSF00012)the Open Fund of the State Key Laboratory of Satellite Ocean Environment Dynamics at the Second Institute of OceanographySOA(Grant No.SOED1305)
文摘A modified Gauss-Markov model with weighted constraints was constructed by combining satellite altimeter and tide gauge records. Vertical motion rates of nine tide gauge stations around the Bohal Sea and Yellow Sea are estimated. This is the first time systematic estimates have been derived in this region. Downward trends were seen at the six tide gauge stations located at Tanggu, Longkou, Laohutan, Bayuquan, Xiaochangshan, and Yantai; with vertical motion rates of-1.82±0.50, -1.65±0.46, -0.88±0.42, -0.58±0.62, -0.13±0.43, and -0.01±0.43 mm/yr, respectively. Upward trends were seen at the three tide gauge stations located at Qinhuangdao, Huludao and Chengshantou; with vertical motion rates of 1.12±0.46, 0.55±0.49 and 0.26±0.44 mm/yr, respectively. There was significant subsidence in Tanggu and Longkou, and a rising trend in Qinhuangdao. According to our results, the rate of sea level rise calculated from these tide gauge records can be improved using a more accurate measurement of the land elevation accounting for lifting or subsidence. The model derived can be used to estimate vertical motions of tide gauge stations, and can be widely applied to revise the benchmark levels of tide gauges.
