Mussel aquaculture and large yellow croaker aquaculture areas and their environmental characteristics in Zhoushan were analyzed using satellite data and in-situ surveys.A new two-step remote sensing method was propose...Mussel aquaculture and large yellow croaker aquaculture areas and their environmental characteristics in Zhoushan were analyzed using satellite data and in-situ surveys.A new two-step remote sensing method was proposed and applied to determine the basic environmental characteristics of the best mussel and large yellow croaker aquaculture areas.This methodology includes the first step of extraction of the location distribution and the second step of the extraction of internal environmental factors.The fishery ranching index(FRI1,FRI2)was established to extract the mussel and the large yellow croaker aquaculture area in Zhoushan,using Gaofen-1(GF-1)and Gaofen-6(GF-6)satellite data with a special resolution of 2 m.In the second step,the environmental factors such as sea surface temperature(SST),chlorophyll a(Chl-a)concentration,current and tide,suspended sediment concentration(SSC)in mussel aquaculture area and large yellow croaker aquaculture area were extracted and analyzed in detail.The results show the following three points.(1)For the extraction of the mussel aquaculture area,FRI1 and FRI2 are complementary,and the combination of FRI1 and FRI2 is suitable to extract the mussel aquaculture area.As for the large yellow croaker aquaculture area extraction,FRI2 is suitable.(2)Mussel aquaculture and the large yellow croaker aquaculture area in Zhoushan are mainly located on the side near the islands that are away from the eastern open waters.The water environment factor template suitable for mussel and large yellow croaker aquaculture was determined.(3)This two-step remote sensing method can be used for the preliminary screening of potential site selection for the mussels and large yellow croaker aquaculture area in the future.the fishery ranching index(FRI1,FRI2)in this paper can be applied to extract the mussel and large yellow croaker aquaculture areas in coastal waters around the world.展开更多
Traditional Chinese villages,vital carriers of traditional culture,have faced significant alterations due to urbanization in recent years,urgently necessitating artificial intelligence data updates.This study integrat...Traditional Chinese villages,vital carriers of traditional culture,have faced significant alterations due to urbanization in recent years,urgently necessitating artificial intelligence data updates.This study integrates high spatial resolution remote sensing imagery with deep learning techniques,proposing a novel method for identifying rooftops of traditional Chinese village buildings using high-definition remote sensing images.Using 0.54 m spatial resolution imagery of traditional village areas as the data source,this method analyzes the geometric and spectral image characteristics of village building rooftops.It constructs a deep learning feature sample library tailored to the target types.Employing a semantically enhanced version of the improved Mask R-CNN(Mask Region-based Convolutional Neural Network)for building recognition,the study conducts experiments on localized imagery from different regions.The results demonstrated that the modified Mask R-CNN effectively identifies traditional village building rooftops,achieving an of 0.7520 and an of 0.7400.It improves the current problem of misidentification and missed detection caused by feature heterogeneity.This method offers a viable and effective approach for industrialized data monitoring of traditional villages,contributing to their sustainable development.展开更多
The exploration of building detection plays an important role in urban planning,smart city and military.Aiming at the problem of high overlapping ratio of detection frames for dense building detection in high resoluti...The exploration of building detection plays an important role in urban planning,smart city and military.Aiming at the problem of high overlapping ratio of detection frames for dense building detection in high resolution remote sensing images,we present an effective YOLOv3 framework,corner regression-based YOLOv3(Correg-YOLOv3),to localize dense building accurately.This improved YOLOv3 algorithm establishes a vertex regression mechanism and an additional loss item about building vertex offsets relative to the center point of bounding box.By extending output dimensions,the trained model is able to output the rectangular bounding boxes and the building vertices meanwhile.Finally,we evaluate the performance of the Correg-YOLOv3 on our self-produced data set and provide a comparative analysis qualitatively and quantitatively.The experimental results achieve high performance in precision(96.45%),recall rate(95.75%),F1 score(96.10%)and average precision(98.05%),which were 2.73%,5.4%,4.1%and 4.73%higher than that of YOLOv3.Therefore,our proposed algorithm effectively tackles the problem of dense building detection in high resolution images.展开更多
目的探讨高分辨率CT评估免疫治疗相关性肺炎患者诊疗效果及预后。方法2021年5月至2023年5月于肇庆市第一人民医院进行免疫治疗的恶性肿瘤患者1205例,其中32例治疗后并发免疫相关性肺炎,将所有患者的临床资料进行回顾性分析,对所有患者...目的探讨高分辨率CT评估免疫治疗相关性肺炎患者诊疗效果及预后。方法2021年5月至2023年5月于肇庆市第一人民医院进行免疫治疗的恶性肿瘤患者1205例,其中32例治疗后并发免疫相关性肺炎,将所有患者的临床资料进行回顾性分析,对所有患者进行高分辨率计算机断层扫描(CT),分析患者免疫检查点抑制剂治疗情况,免疫相关性肺炎患者临床症状及影像学表现,免疫相关性肺炎出现的时间、诊疗效果及预后。结果14例非小细胞肺癌患者及6例肺部低分化肉瘤样癌均采用纳武力尤单抗注射液静脉滴注治疗,用药剂量为3 mg/kg,治疗频次为每半个月1次;12例非小细胞肺癌患者采用信迪利单抗静脉滴注治疗,剂量为200 mg/次,频次为每21 d 1次。32例免疫相关性肺炎患者的临床分级情况为:2级3例,3级20例,4级9例。12例为对称分布,而20例为非对称分布。患者分型情况如下:20例为磨玻璃型,6例为实变型,6例为网格型。其中有23例伴有胸膜变厚,23例纵隔淋巴结受累,12例伴有支气管扩张,9例伴有小叶间隔变厚,9例伴有多发小叶中心结节,3例伴有胸腔积液。出现免疫相关性肺炎后,32例患者均停止PD-1抑制剂治疗,而应用糖皮质激素连续治疗1~6周,13例出院。结论采用高分辨率CT可以对免疫性肺炎进行诊断,并且有助于对患者进行准确分级、分型,对于已经明确诊断的免疫相关性肺炎患者,应立即停止PD-1抑制剂治疗,之后采用糖皮质激素对患者进行治疗,必要时还可联合抗生素治疗。展开更多
In a previous companion paper [1], the potential advantages of high resolution radar for improved target detection were introduced. In particular, the concept of shaping both the transmitted waveform and the receiving...In a previous companion paper [1], the potential advantages of high resolution radar for improved target detection were introduced. In particular, the concept of shaping both the transmitted waveform and the receiving processor in accordance to the expected target down-range profile was highlighted and performance predictions were provided. In this paper, we present and evaluate an adaptive scheme devised to on-line estimate the target profile, in order to overcome a limited a-priori knowledge. In addition, we introduce a more general model of target impulse response, based on a statistical description, and we discuss the corresponding processing scheme and detection performance.展开更多
This paper studies a detection method of targets of high resolution radar operating at the band of millimeter-wave(32-38GHz) under the background of the clutters, and proposes a new nonparametric detection method, whi...This paper studies a detection method of targets of high resolution radar operating at the band of millimeter-wave(32-38GHz) under the background of the clutters, and proposes a new nonparametric detection method, which not only does less computation, but also is able to detect multiple extended targets radially distributed along distance "corridor", based on the position (range) correlation information of one-dimensional range images(or called range profiles) of high resolution radar targets. The experimental results, on the real echo data of tank illuminated by the millimeter-wave stepped frequency high resolution radar, have certified that such a method presented in this paper is a very effective detection method for multiple extended targets.展开更多
Some studies about road vector map change detection were done in this paper. Firstly, on the basis of old road vector data, the original high resolution remote sensing image was cut into segments. Then, gray analysis ...Some studies about road vector map change detection were done in this paper. Firstly, on the basis of old road vector data, the original high resolution remote sensing image was cut into segments. Then, gray analysis and edge extraction of those segments were done so that changes of roads could be detected. Finally, according to the vector data and gray information of roads which were not changed, road templates were extracted and saved automatically. This method was performed on the World View high resolution image of certain parts in the country. The detection result shows that detection correctness is 79.56% and completeness can reach 97.72%. Moreover, the extracted road templates are essentials for the template matching method of road extraction.展开更多
The Kuiyang-ST2000 deep-towed high-resolution multichannel seismic system was designed by the First Institute of Oceanography,Ministry of Natural Resources(FIO,MNR).The system is mainly composed of a plasma spark sour...The Kuiyang-ST2000 deep-towed high-resolution multichannel seismic system was designed by the First Institute of Oceanography,Ministry of Natural Resources(FIO,MNR).The system is mainly composed of a plasma spark source(source level:216 dB,main frequency:750 Hz,frequency bandwidth:150-1200 Hz)and a towed hydrophone streamer with 48 channels.Because the source and the towed hydrophone streamer are constantly moving according to the towing configuration,the accurate positioning of the towing hydrophone array and the moveout correction of deep-towed multichannel seismic data processing before imaging are challenging.Initially,according to the characteristics of the system and the towing streamer shape in deep water,travel-time positioning method was used to construct the hydrophone streamer shape,and the results were corrected by using the polynomial curve fitting method.Then,a new data-processing workflow for Kuiyang-ST2000 system data was introduced,mainly including float datum setting,residual static correction,phase-based moveout correction,which allows the imaging algorithms of conventional marine seismic data processing to extend to deep-towed seismic data.We successfully applied the Kuiyang-ST2000 system and methodology of data processing to a gas hydrate survey of the Qiongdongnan and Shenhu areas in the South China Sea,and the results show that the profile has very high vertical and lateral resolutions(0.5 m and 8 m,respectively),which can provide full and accurate details of gas hydrate-related and geohazard sedimentary and structural features in the South China Sea.展开更多
Traditional visual interpretation is often inefficient due to its excessively workload professional knowledge and strong subjectivity.Therefore,building an automatic interpretation model on high spatial resolution rem...Traditional visual interpretation is often inefficient due to its excessively workload professional knowledge and strong subjectivity.Therefore,building an automatic interpretation model on high spatial resolution remote sensing images is the key to the quick and efficient interpretation of earthquake-triggered landslides.Aiming at addressing this problem,a landslide interpretation model of high-resolution images based on bag of visual word(BoVW)feature was proposed.The high-resolution images were pre-processed,and then BoVW feature and support vector machine(SVM)was adopted to establish an automatic landslide interpretation model.This model was further compared with the currently widely used Histogram of Oriented Gradient(HoG)feature extraction model.In order to test the effectiveness of the method,typical landslide images were selected to construct a landslide sample library,which was subsequently utilized as the foundation for conducting an experimental study.The results show that the accuracy of landslide extraction using this method reaches as high as 89%,indicating that the method can be used for the automatic interpretation of landslides in disaster-prone areas,and has high practical value for regional disaster prevention and damage reduction.展开更多
In order to achieve refined precipitation grid data with high accuracy and high spatial resolution,hourly precipitation grid dataset with 1 km spatial resolution in Anhui Province from May to September (in the rainy s...In order to achieve refined precipitation grid data with high accuracy and high spatial resolution,hourly precipitation grid dataset with 1 km spatial resolution in Anhui Province from May to September (in the rainy season) in 2016 and from August 2017 to July 2018 was established based on thin plate smoothing spline (TPS),which meets the needs of climate change research and meteorological disaster risk assessment.The interpolation errors were then analyzed.The grid precipitation product obtained based on thin plate smoothing spline,CLDAS-FAST and CLDAS-FRT were evaluated.The results show that the interpolated values of hourly precipitation by thin plate smoothing spline are close to the observed values in the rainy season of 2016.The errors are generally below 0.9 mm/h.However,the errors of precipitation in the mountainous areas of eastern Huaibei and western Anhui are above 1.2 mm/h.On monthly scale,the errors in June and July are the largest,and the proportion of absolute values of the errors ≥2 mm/h is up to 2.0% in June and 2.2% in July.The errors in September are the smallest,and the proportion of absolute values of the errors ≥2 mm/h is only 0.6%.The root mean square (RMSE) is only 0.37 mm/h,and the correlation coefficient (COR) is 0.93.The interpolation accuracy of CLDAS-FRT is the highest,with the smallest RMSE (0.65 mm/h) and mean error ( ME =0.01 mm/h),and the largest COR (0.81).The accuracy of the precipitation product obtained by thin plate smoothing spline interpolation is close to that of CLDAS-FAST.Its RMSE is up to 0.80 mm/h,and its ME is only -0.01 mm/h.Its COR is 0.73,but its bias (BIAS) is up to 1.06 mm/h.展开更多
目的对比常规薄层图像和高分辨率联合最大密度投影(high resolution combined with maximum intensity projection,HR-MIP)重建图像在检出肺内结节方面的差异,评价HR-MIP对肺内结节的检出效能。方法随机选取天津医科大学朱宪彝纪念医院2...目的对比常规薄层图像和高分辨率联合最大密度投影(high resolution combined with maximum intensity projection,HR-MIP)重建图像在检出肺内结节方面的差异,评价HR-MIP对肺内结节的检出效能。方法随机选取天津医科大学朱宪彝纪念医院2021年12月至2022年6月期间行胸部CT检查的患者共90例,其中男性52例,女性38例,年龄18~82(43±12.5)岁。分别利用2 mm层厚的常规薄层图像和HR-MIP(厚度4 mm)重建图像观察肺内结节的情况,根据结节大小分为<5 mm和≥5 mm两组。两位诊断医师分别对两组图像进行阅片并记录结节的数量、大小及性质(实性、部分实性、磨玻璃),同时记录阅读每例患者阅片时所耗费的时间。比较常规薄层图像和HR-MIP在结节检出率及耗费时间方面的差异。采用配对t检验、χ^(2)检验进行统计学分析。结果90例患者共有结节313个,<5 mm 255个、≥5 mm 58个,其中常规薄层图像和HR-MIP分别检出结节的总数为253个(80.1%)、285个(91.0%),HR-MIP检出率高于常规薄层图像,差异有统计学意义(χ^(2)=13.523,P<0.001);其中常规薄层图像和HR-MIP检出<5 mm及≥5 mm结节的数量分别为(208比235)和(45比50),<5 mm组差异有统计学意义(χ^(2)=12.517,P<0.001),≥5 mm组差异无统计学意义(χ^(2)=1.408,P=0.237)。结节性质方面:实性、部分实性及磨玻璃密度结节分别有261、22、30个;常规薄层图像和HR-MIP检出实性、部分实性和磨玻璃密度结节分别为(210比245)、(15比17)和(28比23),其中两种方法实性结节检出率差异有统计学意义(χ^(2)=34.812,P<0.001),部分实性和磨玻璃密度结节检出率差异均无统计学意义(χ^(2)=0.631,P=0.407;χ^(2)=1.231,P=0.224)。常规薄层图像耗时为(215.3±23.8)s,HR-MIP耗时为(133.2±19.1)s,差异有统计学意义(t=18.013,P<0.001)。结论利用HR-MIP重建后阅片能够提高肺内实性小结节的检出率并且可以缩短阅片时间、提高诊断效率,但是对于部分实性及磨玻璃密度小结节仍需仔细观察。展开更多
Projections of future precipitation change over China are studied based on the output of a global AGCM, ECHAM5, with a high resolution of T319 (equivalent to 40 km). Evaluation of the model’s performance in simulatin...Projections of future precipitation change over China are studied based on the output of a global AGCM, ECHAM5, with a high resolution of T319 (equivalent to 40 km). Evaluation of the model’s performance in simulating present-day precipitation shows encouraging results. The spatial distributions of both mean and extreme precipitation, especially the locations of main precipitation centers, are reproduced reasonably. The simulated annual cycle of precipitation is close to the observed. The performance of the model over eastern China is generally better than that over western China. A weakness of the model is the overestimation of precipitation over northern and western China. Analyses on the potential change in precipitation projected under the A1B scenario show that both annual mean precipitation intensity and extreme precipitation would increase significantly over southeastern China. The percentage increase in extreme precipitation is larger than that of mean precipitation. Meanwhile, decreases in mean and extreme precipitation are evident over the southern Tibetan Plateau. For precipitation days, extreme precipitation days are projected to increase over all of China. Both consecutive dry days over northern China and consecutive wet days over southern China would decrease.展开更多
基金The National Key Research and Development Program of China under contract Nos 2023YFD2401900 and 2020YFD09008004the National Natural Science Foundation of China Key International(Regional)Cooperative Research Project under contract No.42020104009the Basic Public Welfare Research Program of Zhejiang Province under contract No.LGF21D010004.
文摘Mussel aquaculture and large yellow croaker aquaculture areas and their environmental characteristics in Zhoushan were analyzed using satellite data and in-situ surveys.A new two-step remote sensing method was proposed and applied to determine the basic environmental characteristics of the best mussel and large yellow croaker aquaculture areas.This methodology includes the first step of extraction of the location distribution and the second step of the extraction of internal environmental factors.The fishery ranching index(FRI1,FRI2)was established to extract the mussel and the large yellow croaker aquaculture area in Zhoushan,using Gaofen-1(GF-1)and Gaofen-6(GF-6)satellite data with a special resolution of 2 m.In the second step,the environmental factors such as sea surface temperature(SST),chlorophyll a(Chl-a)concentration,current and tide,suspended sediment concentration(SSC)in mussel aquaculture area and large yellow croaker aquaculture area were extracted and analyzed in detail.The results show the following three points.(1)For the extraction of the mussel aquaculture area,FRI1 and FRI2 are complementary,and the combination of FRI1 and FRI2 is suitable to extract the mussel aquaculture area.As for the large yellow croaker aquaculture area extraction,FRI2 is suitable.(2)Mussel aquaculture and the large yellow croaker aquaculture area in Zhoushan are mainly located on the side near the islands that are away from the eastern open waters.The water environment factor template suitable for mussel and large yellow croaker aquaculture was determined.(3)This two-step remote sensing method can be used for the preliminary screening of potential site selection for the mussels and large yellow croaker aquaculture area in the future.the fishery ranching index(FRI1,FRI2)in this paper can be applied to extract the mussel and large yellow croaker aquaculture areas in coastal waters around the world.
文摘Traditional Chinese villages,vital carriers of traditional culture,have faced significant alterations due to urbanization in recent years,urgently necessitating artificial intelligence data updates.This study integrates high spatial resolution remote sensing imagery with deep learning techniques,proposing a novel method for identifying rooftops of traditional Chinese village buildings using high-definition remote sensing images.Using 0.54 m spatial resolution imagery of traditional village areas as the data source,this method analyzes the geometric and spectral image characteristics of village building rooftops.It constructs a deep learning feature sample library tailored to the target types.Employing a semantically enhanced version of the improved Mask R-CNN(Mask Region-based Convolutional Neural Network)for building recognition,the study conducts experiments on localized imagery from different regions.The results demonstrated that the modified Mask R-CNN effectively identifies traditional village building rooftops,achieving an of 0.7520 and an of 0.7400.It improves the current problem of misidentification and missed detection caused by feature heterogeneity.This method offers a viable and effective approach for industrialized data monitoring of traditional villages,contributing to their sustainable development.
基金National Natural Science Foundation of China(No.41871305)National Key Research and Development Program of China(No.2017YFC0602204)+2 种基金Fundamental Research Funds for the Central Universities,China University of Geosciences(Wuhan)(No.CUGQY1945)Open Fund of Key Laboratory of Geological Survey and Evaluation of Ministry of Education and the Fundamental Research Funds for the Central Universities(No.GLAB2019ZR02)Open Fund of Laboratory of Urban Land Resources Monitoring and Simulation,Ministry of Natural Resources,China(No.KF-2020-05-068)。
文摘The exploration of building detection plays an important role in urban planning,smart city and military.Aiming at the problem of high overlapping ratio of detection frames for dense building detection in high resolution remote sensing images,we present an effective YOLOv3 framework,corner regression-based YOLOv3(Correg-YOLOv3),to localize dense building accurately.This improved YOLOv3 algorithm establishes a vertex regression mechanism and an additional loss item about building vertex offsets relative to the center point of bounding box.By extending output dimensions,the trained model is able to output the rectangular bounding boxes and the building vertices meanwhile.Finally,we evaluate the performance of the Correg-YOLOv3 on our self-produced data set and provide a comparative analysis qualitatively and quantitatively.The experimental results achieve high performance in precision(96.45%),recall rate(95.75%),F1 score(96.10%)and average precision(98.05%),which were 2.73%,5.4%,4.1%and 4.73%higher than that of YOLOv3.Therefore,our proposed algorithm effectively tackles the problem of dense building detection in high resolution images.
文摘目的探讨高分辨率CT评估免疫治疗相关性肺炎患者诊疗效果及预后。方法2021年5月至2023年5月于肇庆市第一人民医院进行免疫治疗的恶性肿瘤患者1205例,其中32例治疗后并发免疫相关性肺炎,将所有患者的临床资料进行回顾性分析,对所有患者进行高分辨率计算机断层扫描(CT),分析患者免疫检查点抑制剂治疗情况,免疫相关性肺炎患者临床症状及影像学表现,免疫相关性肺炎出现的时间、诊疗效果及预后。结果14例非小细胞肺癌患者及6例肺部低分化肉瘤样癌均采用纳武力尤单抗注射液静脉滴注治疗,用药剂量为3 mg/kg,治疗频次为每半个月1次;12例非小细胞肺癌患者采用信迪利单抗静脉滴注治疗,剂量为200 mg/次,频次为每21 d 1次。32例免疫相关性肺炎患者的临床分级情况为:2级3例,3级20例,4级9例。12例为对称分布,而20例为非对称分布。患者分型情况如下:20例为磨玻璃型,6例为实变型,6例为网格型。其中有23例伴有胸膜变厚,23例纵隔淋巴结受累,12例伴有支气管扩张,9例伴有小叶间隔变厚,9例伴有多发小叶中心结节,3例伴有胸腔积液。出现免疫相关性肺炎后,32例患者均停止PD-1抑制剂治疗,而应用糖皮质激素连续治疗1~6周,13例出院。结论采用高分辨率CT可以对免疫性肺炎进行诊断,并且有助于对患者进行准确分级、分型,对于已经明确诊断的免疫相关性肺炎患者,应立即停止PD-1抑制剂治疗,之后采用糖皮质激素对患者进行治疗,必要时还可联合抗生素治疗。
文摘In a previous companion paper [1], the potential advantages of high resolution radar for improved target detection were introduced. In particular, the concept of shaping both the transmitted waveform and the receiving processor in accordance to the expected target down-range profile was highlighted and performance predictions were provided. In this paper, we present and evaluate an adaptive scheme devised to on-line estimate the target profile, in order to overcome a limited a-priori knowledge. In addition, we introduce a more general model of target impulse response, based on a statistical description, and we discuss the corresponding processing scheme and detection performance.
文摘This paper studies a detection method of targets of high resolution radar operating at the band of millimeter-wave(32-38GHz) under the background of the clutters, and proposes a new nonparametric detection method, which not only does less computation, but also is able to detect multiple extended targets radially distributed along distance "corridor", based on the position (range) correlation information of one-dimensional range images(or called range profiles) of high resolution radar targets. The experimental results, on the real echo data of tank illuminated by the millimeter-wave stepped frequency high resolution radar, have certified that such a method presented in this paper is a very effective detection method for multiple extended targets.
文摘Some studies about road vector map change detection were done in this paper. Firstly, on the basis of old road vector data, the original high resolution remote sensing image was cut into segments. Then, gray analysis and edge extraction of those segments were done so that changes of roads could be detected. Finally, according to the vector data and gray information of roads which were not changed, road templates were extracted and saved automatically. This method was performed on the World View high resolution image of certain parts in the country. The detection result shows that detection correctness is 79.56% and completeness can reach 97.72%. Moreover, the extracted road templates are essentials for the template matching method of road extraction.
基金Supported by the National Key R&D Program of China(No.2016YFC0303900)the Laoshan Laboratory(Nos.MGQNLM-KF201807,LSKJ202203604)the National Natural Science Foundation of China(No.42106072)。
文摘The Kuiyang-ST2000 deep-towed high-resolution multichannel seismic system was designed by the First Institute of Oceanography,Ministry of Natural Resources(FIO,MNR).The system is mainly composed of a plasma spark source(source level:216 dB,main frequency:750 Hz,frequency bandwidth:150-1200 Hz)and a towed hydrophone streamer with 48 channels.Because the source and the towed hydrophone streamer are constantly moving according to the towing configuration,the accurate positioning of the towing hydrophone array and the moveout correction of deep-towed multichannel seismic data processing before imaging are challenging.Initially,according to the characteristics of the system and the towing streamer shape in deep water,travel-time positioning method was used to construct the hydrophone streamer shape,and the results were corrected by using the polynomial curve fitting method.Then,a new data-processing workflow for Kuiyang-ST2000 system data was introduced,mainly including float datum setting,residual static correction,phase-based moveout correction,which allows the imaging algorithms of conventional marine seismic data processing to extend to deep-towed seismic data.We successfully applied the Kuiyang-ST2000 system and methodology of data processing to a gas hydrate survey of the Qiongdongnan and Shenhu areas in the South China Sea,and the results show that the profile has very high vertical and lateral resolutions(0.5 m and 8 m,respectively),which can provide full and accurate details of gas hydrate-related and geohazard sedimentary and structural features in the South China Sea.
基金the National Key R&D Program of China(2019YFC1510700)the Sichuan Science and Technology Program(2022YFS0539)the Geomatics Technology and Application Key Laboratory of Qinghai Province,China(QHDX-2018-07).
文摘Traditional visual interpretation is often inefficient due to its excessively workload professional knowledge and strong subjectivity.Therefore,building an automatic interpretation model on high spatial resolution remote sensing images is the key to the quick and efficient interpretation of earthquake-triggered landslides.Aiming at addressing this problem,a landslide interpretation model of high-resolution images based on bag of visual word(BoVW)feature was proposed.The high-resolution images were pre-processed,and then BoVW feature and support vector machine(SVM)was adopted to establish an automatic landslide interpretation model.This model was further compared with the currently widely used Histogram of Oriented Gradient(HoG)feature extraction model.In order to test the effectiveness of the method,typical landslide images were selected to construct a landslide sample library,which was subsequently utilized as the foundation for conducting an experimental study.The results show that the accuracy of landslide extraction using this method reaches as high as 89%,indicating that the method can be used for the automatic interpretation of landslides in disaster-prone areas,and has high practical value for regional disaster prevention and damage reduction.
基金Supported by New Technology Integration Project of Anhui Meteorological Bureau(AHXJ201704)Project for Masters and Doctors of Anhui Meteorological Bureau(RC201701)
文摘In order to achieve refined precipitation grid data with high accuracy and high spatial resolution,hourly precipitation grid dataset with 1 km spatial resolution in Anhui Province from May to September (in the rainy season) in 2016 and from August 2017 to July 2018 was established based on thin plate smoothing spline (TPS),which meets the needs of climate change research and meteorological disaster risk assessment.The interpolation errors were then analyzed.The grid precipitation product obtained based on thin plate smoothing spline,CLDAS-FAST and CLDAS-FRT were evaluated.The results show that the interpolated values of hourly precipitation by thin plate smoothing spline are close to the observed values in the rainy season of 2016.The errors are generally below 0.9 mm/h.However,the errors of precipitation in the mountainous areas of eastern Huaibei and western Anhui are above 1.2 mm/h.On monthly scale,the errors in June and July are the largest,and the proportion of absolute values of the errors ≥2 mm/h is up to 2.0% in June and 2.2% in July.The errors in September are the smallest,and the proportion of absolute values of the errors ≥2 mm/h is only 0.6%.The root mean square (RMSE) is only 0.37 mm/h,and the correlation coefficient (COR) is 0.93.The interpolation accuracy of CLDAS-FRT is the highest,with the smallest RMSE (0.65 mm/h) and mean error ( ME =0.01 mm/h),and the largest COR (0.81).The accuracy of the precipitation product obtained by thin plate smoothing spline interpolation is close to that of CLDAS-FAST.Its RMSE is up to 0.80 mm/h,and its ME is only -0.01 mm/h.Its COR is 0.73,but its bias (BIAS) is up to 1.06 mm/h.
文摘目的对比常规薄层图像和高分辨率联合最大密度投影(high resolution combined with maximum intensity projection,HR-MIP)重建图像在检出肺内结节方面的差异,评价HR-MIP对肺内结节的检出效能。方法随机选取天津医科大学朱宪彝纪念医院2021年12月至2022年6月期间行胸部CT检查的患者共90例,其中男性52例,女性38例,年龄18~82(43±12.5)岁。分别利用2 mm层厚的常规薄层图像和HR-MIP(厚度4 mm)重建图像观察肺内结节的情况,根据结节大小分为<5 mm和≥5 mm两组。两位诊断医师分别对两组图像进行阅片并记录结节的数量、大小及性质(实性、部分实性、磨玻璃),同时记录阅读每例患者阅片时所耗费的时间。比较常规薄层图像和HR-MIP在结节检出率及耗费时间方面的差异。采用配对t检验、χ^(2)检验进行统计学分析。结果90例患者共有结节313个,<5 mm 255个、≥5 mm 58个,其中常规薄层图像和HR-MIP分别检出结节的总数为253个(80.1%)、285个(91.0%),HR-MIP检出率高于常规薄层图像,差异有统计学意义(χ^(2)=13.523,P<0.001);其中常规薄层图像和HR-MIP检出<5 mm及≥5 mm结节的数量分别为(208比235)和(45比50),<5 mm组差异有统计学意义(χ^(2)=12.517,P<0.001),≥5 mm组差异无统计学意义(χ^(2)=1.408,P=0.237)。结节性质方面:实性、部分实性及磨玻璃密度结节分别有261、22、30个;常规薄层图像和HR-MIP检出实性、部分实性和磨玻璃密度结节分别为(210比245)、(15比17)和(28比23),其中两种方法实性结节检出率差异有统计学意义(χ^(2)=34.812,P<0.001),部分实性和磨玻璃密度结节检出率差异均无统计学意义(χ^(2)=0.631,P=0.407;χ^(2)=1.231,P=0.224)。常规薄层图像耗时为(215.3±23.8)s,HR-MIP耗时为(133.2±19.1)s,差异有统计学意义(t=18.013,P<0.001)。结论利用HR-MIP重建后阅片能够提高肺内实性小结节的检出率并且可以缩短阅片时间、提高诊断效率,但是对于部分实性及磨玻璃密度小结节仍需仔细观察。
基金supported by the National Key Technologies R&D Program(Grant No. 2007BAC29B03)China-UK-Swiss Adaptingto Climate Change in China Project (ACCC)-Climate Sciencethe National Natural Science Foundation of China (Grant No. 40890054)
文摘Projections of future precipitation change over China are studied based on the output of a global AGCM, ECHAM5, with a high resolution of T319 (equivalent to 40 km). Evaluation of the model’s performance in simulating present-day precipitation shows encouraging results. The spatial distributions of both mean and extreme precipitation, especially the locations of main precipitation centers, are reproduced reasonably. The simulated annual cycle of precipitation is close to the observed. The performance of the model over eastern China is generally better than that over western China. A weakness of the model is the overestimation of precipitation over northern and western China. Analyses on the potential change in precipitation projected under the A1B scenario show that both annual mean precipitation intensity and extreme precipitation would increase significantly over southeastern China. The percentage increase in extreme precipitation is larger than that of mean precipitation. Meanwhile, decreases in mean and extreme precipitation are evident over the southern Tibetan Plateau. For precipitation days, extreme precipitation days are projected to increase over all of China. Both consecutive dry days over northern China and consecutive wet days over southern China would decrease.
