Spatial interpolation using conditional generative adversarial neural networks

ABSTRACT

Spatial interpolation is a traditional geostatistical operation that aims at predicting the attribute values of unobserved locations given a sample of data defined on point supports. However, the continuity and heterogeneity underlying spatial data are too complex to be approximated by classic statistical models. Deep learning models, especially the idea of conditional generative adversarial networks (CGANs), provide us with a perspective for formalizing spatial interpolation as a conditional generative task. In this article, we design a novel deep learning architecture named conditional encoder-decoder generative adversarial neural networks (CEDGANs) for spatial interpolation, therein combining the encoder-decoder structure with adversarial learning to capture deep representations of sampled spatial data and their interactions with local structural patterns. A case study on elevations in China demonstrates the ability of our model to achieve outstanding interpolation results compared to benchmark methods. Further experiments uncover the learned spatial knowledge in the model’s hidden layers and test the potential to generalize our adversarial interpolation idea across domains. This work is an endeavor to investigate deep spatial knowledge using artificial intelligence. The proposed model can benefit practical scenarios and enlighten future research in various geographical applications related to spatial prediction.     

Mid- and far-infrared variability of PV Cep

We present the collection of all the mid- and far-IR observations (λ=3–170 μm) of the young eruptive variable PV Cep available so far in the literature. These data allow us to confirm that flux variability is a prominent feature at mid-IR wavelength (λ=3–25 μm). Color-magnitude plots clearly indicate that the observed variability is not extinction-driven, but mainly influenced by fluctuations of the mass accretion rate. We interpret such variability as due to a hot spot created onto the stellar surface by the column of accreting matter, which heats the inner parts of the disk and determines the observed increase of the near- mid-IR luminosity. A quantitative characterization is given for both the spot itself and the additional thermal component created by it. Far-IR data (λ=60–170 μm) are consistent with the presence of a temperature stratification in a massive and quite un-evolved circumstellar disk.     

全球深水-超深水油气勘探历程与发展趋势

全球深水-超深水油气勘探经历了深水探索发现（1959—1983年）、深水快速发展与超深水探索（1984—2009年）、深水-超深水稳定发展（2010年至今）3个阶段,形成了以墨西哥湾、巴西东部海域和西非海域为主的深水成熟勘探区,和以拉美东北部、东非、东地中海等为主的超深水新领域的勘探格局。2011年以来,全球深水-超深水勘探投入呈“两段式”特点,2011—2014年勘探投资和探井工作量投入呈现增长态势,处于历史高位;2014年国际油价下跌以来,勘探投入大幅缩减,投资项目多集中于拉丁美洲、北美洲和非洲重点领域。储量发现表现为“集中分布,多点突破”,东非、东地中海、黑海盆地天然气新领域和圭亚那海域石油新领域实现突破,发现时间集中于2011—2015年,水深集中在1500～2400 m超深水。深水-超深水领域油气资源潜力巨大,技术进步使得勘探竞争优势逐渐增强,在国际油价逐步回升的背景下,深水投资不断加大,未来深水成熟区继续挖潜,东非、东地中海、黑海、苏里南等深水-超深水新区不断实现突破,将继续引领全球深水-超深水油气勘探方向,推动深水-超深水油气勘探进入新的储量增长阶段。     

On the Relationship Between the Jets from X-Ray Binaries and Agn

The scale invariance model (Heinz, S. and Sunyaev, R.A.: 2003, MNRAS 343, L59) can be used to derive robust scaling relations between the radio luminosity from accreting black holes and the black hole mass and accretion rate. These relations agree well with the recently found “fundamental plane” of black hole activity (Merloni, A., Heinz, S. and Di Matteo, T.: 2003, MNRAS 345, 1057). This relation provides a new, powerful tool for the comparison of jets from black holes of different masses and accretion rates. The regression coefficients of this relation contain information about the nature of the X-ray emission mechanism driving the correlation. We argue that X-ray synchrotron emission from the base of the jets is unlikely to be the dominant contribution to the X-ray spectrum in most of the sources.     

Pair production in a strong time-depending magnetic field: The effect of a strong gravitational field

We present the calculation of the probability production of an electron–positron pair in the presence of a strong magnetic field with time-varying strength. The calculation takes into account the presence of a strong, constant and uniform gravitational field in the same direction of the magnetic field. The results show that the presence of the gravitational field in general enhances very much the production of pairs. In particular, high-energy pairs are more likely produced in the presence of the gravitational field than in Minkowski spacetime.     

Simple vs complex rating curves: accounting for measurement uncertainty,slope ratio and sample size

Multiple segmented rating curves have been proposed to better capture the variability of the physical and hydraulic characteristics of river–floodplain systems. We evaluate the accuracy of one- and two-segmented rating curves by exploiting a large and unique database of direct measurements of stage and discharge data in more than 200 Swedish catchments. Such a comparison is made by explicitly accounting for the potential impact of measurement uncertainty. This study shows that two-segmented rating curves did not fit the data significantly better, nor did they generate fewer errors than one-segmented rating curves. Two-segmented rating curves were found to be slightly beneficial for low flow when there were strong indications of segmentation, but predicted the rating relationship worse in cases of weak indication of segmentation. Other factors were found to have a larger impact on rating curve errors, such as the uncertainty of the discharge measurements and the type of regression method.     

Seismic physical modeling and quality factor

Accurate Q parameter is hard to be obtained, but there is great difference between Q measurements from different measurement methods in seismic physical modelling. The influence factors, stability and accuracy of different methods are analyzed through standard sample experiment and the seismic physical modelling. Based on this, we proposed an improved method for improving accuracy of pulse transmission method, in which the samples with similar acoustic properties to the test sample are selected as the reference samples. We assess the stability and accuracy of the pulse transmission, pulse transmission insertion, and reflection wave methods for obtaining the quality factor Q using standard and reference samples and seismic physical modeling. The results suggest that the Q-values obtained by the pulse transmission method are strongly affected by diffraction and the error is 50% or greater, whereas the relative error of the improved pulse transmission method is about 10%. By using a theoretical diffraction correction method and the improved measurement method, the differences among the Q-measuring methods can be limited to within 10%.     

Characteristics of Authigenic Pyrite and its Sulfur Isotopes Influenced by Methane Seep—Taking the Core A at Site 79 of the Middle Okinawa Trough as an Example

<正>Objective Authigenic pyrite often develops extensively in marine sediments,which is an important product of sulfate reduction in an anoxic environment.It has a specific appearance and complicated sulfur isotopic properties,and acts as important evidence of methane seep in marine sediments.Strong AOM(anaerobic oxidation of methane)     

A New Potential Caledonian–Indosinian Ore Concentration Area: Evidence from Diagenesis and Mineralization Ages of the Miao'ershan–Yuechengling Region

<正>Objective The Miao’ershan–Yuechengling composite granite,located in northern Guangxi at the western section of the Nanling Range,is a multi-period and multi-stage composite pluton with an exposed area of more than 3000km2(Fig.1).Paleozoic and Proterozoic strata are exposed around it,and magmatic activities mainly occurred during