作物需水量是灌溉工程规划、设计和管理的重要基础数据,充分利用多源数据和先验知识,快速经济地获取精度较高的区域作物需水量对于区域水资源的优化配置具有重要意义。为精确预测作物需水量,该文以长系列实际监测和校核作物系数后计算...作物需水量是灌溉工程规划、设计和管理的重要基础数据,充分利用多源数据和先验知识,快速经济地获取精度较高的区域作物需水量对于区域水资源的优化配置具有重要意义。为精确预测作物需水量,该文以长系列实际监测和校核作物系数后计算得到的作物需水量为硬数据,利用硬数据确定获得最大熵的约束条件,根据软数据获取渠道的不同(部分年份缺失的站点数据、文献中获得的数据、利用灌溉试验数据库中的作物需水量资料,采用协同克立格方法获得的数据、考虑主要地形因子和主要气象要素的影响,采用主成分分析和地理加权回归(geographically weighted regression,GWR)方法获得作物需水量数据以及遥感数据),提出不同来源软数据的概率密度函数表达方法,采用贝叶斯最大熵(Bayesian maximum entropy,BME)方法对不同来源的作物需水量信息进行有机整合。结果表明:除硬数据+文献软数据外,其他数据整合呈现一致结果。华北地区冬小麦作物需水量在豫南地区较小,中部地区黄河北岸有连片的相对高值区,山东需水量相对较高,冀东北的乐亭、唐山附近有相对低值区。除硬数据+文献软数据比不整合的精度低9.41%外,其他软数据源均可不同程度地提高整合效果,硬数据+克立格软数据、硬数据+GWR软数据和硬数据+除文献数据外的其他软数据分别比不整合的精度提高85.33%、85.75%和91.69%。对考虑地形、气象等要素的多源数据进行整合可更好地反映冬小麦作物需水量空间分布的细节,显著提高估算精度,为稀疏监测站点地区水土资源的精准管理和优化配置提供数据支撑。展开更多
Bone marrow edema is a self-limiting, under-recognized condition. It mainly involves the lower limbs. It is characterized by pain and inability to bear weight. Diagnosis is most often based on imaging and by excluding...Bone marrow edema is a self-limiting, under-recognized condition. It mainly involves the lower limbs. It is characterized by pain and inability to bear weight. Diagnosis is most often based on imaging and by excluding other causes. Its exact pathogenesis is still debated and various theories are postulated. Treatment ranges from anti-inflammatories to restricted weight bearing. This overview has tried to revisit this rare and perhaps forgotten clinical-radiological condition.展开更多
Sea surface temperature （SST） is an important variable for understanding interactions between the ocean and the atmosphere. SST fusion is crucial for acquiring SST products of high spatial resolution and coverage. T...Sea surface temperature （SST） is an important variable for understanding interactions between the ocean and the atmosphere. SST fusion is crucial for acquiring SST products of high spatial resolution and coverage. This study introduces a Bayesian maximum entropy （BME） method for blending daily SSTs from multiple satellite sensors. A new spatiotemporal covariance model of an SST field is built to integrate not only single-day SSTs but also time-adjacent SSTs. In addition, AVHRR 30-year SST climatology data are introduced as soft data at the estimation points to improve the accuracy of blended results within the BME framework. The merged SSTs, with a spatial resolution of 4 km and a temporal resolution of 24 hours, are produced in the Western Pacific Ocean region to demonstrate and evaluate the proposed metho- dology. Comparisons with in situ drifting buoy observations show that the merged SSTs are accurate and the bias and root-mean-square errors for the comparison are 0.15℃ and 0.72℃, respectively.展开更多
Inferring the state of heart from the human body surface, electropotential distribution essentially belongs to a problem of 'inverse ECG'. However, the research of 'inverse ECG' is based on and related...Inferring the state of heart from the human body surface, electropotential distribution essentially belongs to a problem of 'inverse ECG'. However, the research of 'inverse ECG' is based on and related to the research of 'forward ECG'. This conclusion comes from the fact that in 'forward ECG' the relation between the biodectric process in the heart and the potential distribution on human body surface is definite and this relation surely can be used to verify the justification of different algorithms of 'inverse ECG'. With the development展开更多
文摘作物需水量是灌溉工程规划、设计和管理的重要基础数据,充分利用多源数据和先验知识,快速经济地获取精度较高的区域作物需水量对于区域水资源的优化配置具有重要意义。为精确预测作物需水量,该文以长系列实际监测和校核作物系数后计算得到的作物需水量为硬数据,利用硬数据确定获得最大熵的约束条件,根据软数据获取渠道的不同(部分年份缺失的站点数据、文献中获得的数据、利用灌溉试验数据库中的作物需水量资料,采用协同克立格方法获得的数据、考虑主要地形因子和主要气象要素的影响,采用主成分分析和地理加权回归(geographically weighted regression,GWR)方法获得作物需水量数据以及遥感数据),提出不同来源软数据的概率密度函数表达方法,采用贝叶斯最大熵(Bayesian maximum entropy,BME)方法对不同来源的作物需水量信息进行有机整合。结果表明:除硬数据+文献软数据外,其他数据整合呈现一致结果。华北地区冬小麦作物需水量在豫南地区较小,中部地区黄河北岸有连片的相对高值区,山东需水量相对较高,冀东北的乐亭、唐山附近有相对低值区。除硬数据+文献软数据比不整合的精度低9.41%外,其他软数据源均可不同程度地提高整合效果,硬数据+克立格软数据、硬数据+GWR软数据和硬数据+除文献数据外的其他软数据分别比不整合的精度提高85.33%、85.75%和91.69%。对考虑地形、气象等要素的多源数据进行整合可更好地反映冬小麦作物需水量空间分布的细节,显著提高估算精度,为稀疏监测站点地区水土资源的精准管理和优化配置提供数据支撑。
文摘Bone marrow edema is a self-limiting, under-recognized condition. It mainly involves the lower limbs. It is characterized by pain and inability to bear weight. Diagnosis is most often based on imaging and by excluding other causes. Its exact pathogenesis is still debated and various theories are postulated. Treatment ranges from anti-inflammatories to restricted weight bearing. This overview has tried to revisit this rare and perhaps forgotten clinical-radiological condition.
基金This study was supported by the National Natural Science Foundation of China （Grant Nos. 41201350 and 41371355）. We sincerely thank the University of North Carolina Bayesian Maximum Entropy （UNC-BME） laboratory at the UNC at Chapel Hill for supplying the BME codes.
文摘Sea surface temperature （SST） is an important variable for understanding interactions between the ocean and the atmosphere. SST fusion is crucial for acquiring SST products of high spatial resolution and coverage. This study introduces a Bayesian maximum entropy （BME） method for blending daily SSTs from multiple satellite sensors. A new spatiotemporal covariance model of an SST field is built to integrate not only single-day SSTs but also time-adjacent SSTs. In addition, AVHRR 30-year SST climatology data are introduced as soft data at the estimation points to improve the accuracy of blended results within the BME framework. The merged SSTs, with a spatial resolution of 4 km and a temporal resolution of 24 hours, are produced in the Western Pacific Ocean region to demonstrate and evaluate the proposed metho- dology. Comparisons with in situ drifting buoy observations show that the merged SSTs are accurate and the bias and root-mean-square errors for the comparison are 0.15℃ and 0.72℃, respectively.
基金Project supported by the National Natural Science Foundation of China
文摘Inferring the state of heart from the human body surface, electropotential distribution essentially belongs to a problem of 'inverse ECG'. However, the research of 'inverse ECG' is based on and related to the research of 'forward ECG'. This conclusion comes from the fact that in 'forward ECG' the relation between the biodectric process in the heart and the potential distribution on human body surface is definite and this relation surely can be used to verify the justification of different algorithms of 'inverse ECG'. With the development
