排序方式： 共有17条查询结果，搜索用时 15 毫秒
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Xianghai Wang Jingzhe Tao Yutong Shen Mingshuang Qin Chuanming Song 《Journal of the Indian Society of Remote Sensing》2018,46(4):667-673
To reduce the possibility of poor efficiency and weak anti-error capability while encoding and transmitting hyperspectral images, we present a distributed source coding scheme for hyperspectral images based on three-dimensional (3D) set partitioning in hierarchical trees (SPIHT). First, the 3D wavelet transform is performed on the hyperspectral image. Thereafter, the low frequency section is regarded as the Key frame and the high frequency section as the Wyner–Ziv frame to enable independent SPIHT coding through different transmission channels. The Wyner–Ziv encoder uses Turbo channel coding to create high frequency information that reflects the details of the image with better anti-error capacity, while the low frequency information shows the main energy of the image. In this study, we used SPIHT coding to acquire a bit stream with quality scalability. Results show that the proposed scheme is more efficient during coding, while at the same time providing improved anti-error capability and quality scalability of the bit stream. 相似文献
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Identification of sedimentary facies with well logs: an indirect approach with multinomial logistic regression and artificial neural network 总被引：1，自引：0，他引：1
Jinliang Zhang Shasha Liu Jingzhe Li Longlong Liu Huimin Liu Zhongqiang Sun 《Arabian Journal of Geosciences》2017,10(11):247
Taking K-successions of the H-Zone of the Pearl River Mouth Basin as a testing example, we used two kinds of approaches to implement the microfacies identification. One is a direct identification, the other is an indirect approach in which we conducted the lithofacies classification first and then identified the microfacies based on previously estimated lithofacies. Both approaches were trained and checked by interpretations of experienced geologists from real subsurface core data. Multinomial logistic regression (MLR) and artificial neural network (ANN) were used in these two approaches as classification algorithms. Cross-validations were implemented. The source data set was randomly divided into training subset and testing subset. Four models, namely, MLR_direct, ANN_direct, MLR_indirect, and ANN_indirect, were trained with the training subset. The result of the testing set shows that the direct approaches (MLR_direct and ANN_direct) perform relatively poor with a total accuracy around 75%. While the indirect approaches (MLR_indirect and ANN_indirect) perform much better with a total accuracy of around 89 and 82%, respectively. This indirect method is simple and reproducible, and it could lead to a robust way of analyzing sedimentary microfacies of horizontal wells with little core data or even are almost never cored while core data are available for nearby vertical wells. 相似文献
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X-CT扫描成像技术在特低渗透储层微观孔隙结构及渗流机理研究中的应用--以西峰油田庄19井区长82储层为例 总被引：28，自引：1，他引：27
鄂尔多斯盆地上三叠统延长组河流-湖泊三角洲相砂岩储层物性受沉积--埋藏--成岩等因素控制.特低渗透储层具有其独特的微观孔隙结构和渗流机理.应用X-CT扫描成像实验技术进行砂岩岩心微观孔隙结构水驱油驱替实验,通过CT扫描切片图像观察分析了注入水微观驱替渗流机理及不同注入压力下的水驱油效率变化分布规律(实验岩心的水驱油效率最高为62%,最低为42%,平均为51. 6%),定量评价了储层微观孔隙结构特征.实验表明低孔、低渗和储层微观双重孔隙结构是造成注入水启动压力、水驱油效率差异大的根本原因;而较强的微观孔隙结构非均质性,是造成注入水波及效率不高、水驱油效率较低的主要原因. 相似文献
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Haibo Ge Bofeng Li Song Jia Liangwei Nie Tianhao Wu Zhe Yang Jingzhe Shang Yanning Zheng Maorong Ge 《地球空间信息科学学报》2022,(1):1-13
With the completion of Chinese BeiDou Navigation Satellite System (BDS), the world has begun to enjoy the Positioning, Navigation, and Timing (PNT) services of ... 相似文献
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Zhang Jinliang Zhang Penghui Xie Jun Dong Zirui Zhang Ming Ding Fang Yuan Yong Li Jingzhe 《地球科学进展》2013,28(9):957-967
Along with the widely used experimental testing technology within 40 years,a number of significant knowledge and results have been achieved in diagenesis of clastic reservoirs an important branch of sedimentology and basin research,which has promoted the exploration and development of hydrocarbon bearing basins. This article encompasses the knowledge system to start an overview of the concept and research history of diagenesis, and to collate some representative classification viewpoints of clastic diagenetic stage. Several advances in recent theoretical and applied aspects of diagenesis, which have enriched the systems and technology series, have been introduced and summarized, including: ① improvement of alkaline diagenesis theory; ② increasingly widespread application in numerical simulation of clastic diagenesis; ③ rapid development of diagenesis within the framework of sequence stratigraphy or depositional facies; ④ preliminary investigation of structural diagenesis; ⑤ in-depth quantitative evaluation of diagenetic facies. Additionally, the research trends of the discipline system of diagenesis should be closely combined and discussed with diagenesis of tight sandstone reservoirs, diagenesis and its temporal properties of hierarchical systems, quantitative research of diagenesis, and integration of diagenesis and other fields. Frontier research and development directions have been prospected in order to bring forward further development of diagenesis, which is benefit for the forecasting and evaluation of the spatial and temporal distribution of hydrocarbon bearing clastic reservoirs. 相似文献
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在全球生态系统之中,湿地发挥着重要作用。湿地易于退化,在干旱地区湿地干缩则表现得更为显著,而湿地作为干旱地区水资源的重要载体,其生态功能不可替代。干旱区湿地对于气候因素的波动以及人为因素的响应更为敏感,湿地所在区域的环境变化可以通过湿地的流转、消亡、干缩、发育等进行深刻反映。因此,开展干旱区湿地研究对区域的水资源合理配置、湿地景观格局变过程及其驱动机制具有重大科学意义。论文抓住湿地扩缩与继发的环境效应的这一核心问题,以国家重要湿地——艾比湖湿地国家级自然保护区为研究靶区,收集了近30年来春、夏、秋3个季节的遥感数据,以随机森林RF为主要分类器,对湿地的空间结构变化、转移特征、时空关联模式、景观格局、空间连通性等进行分析,同时在分析这些主要气象水文要素的多尺度变化的基础上,探索湿地变化对气候变化的响应机制。 相似文献
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风的污染指数及其频率——城市总体规划中的一个气候学问题 总被引：5，自引：0，他引：5
长期来在城市总体规划中,总是按照“盛行风原则”把工业区布置在城市的下风侧,但却并不一定能达到预期的效果.本文阐明了“盛行风原则”的缺点,并自气候学的角度出发,综合考虑影响城市大气污染的各重要气象因素,提出了利用多年常规气象观测记录,计算风的污染指数和不同风向的污染指数频率的公式.按污染指数频率即可确定吹哪一个方向的风时可能出现大气污染的机率最大,从而可以按这一风向把工业区布置在城市的下风侧. 相似文献
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北京城市气温与下垫面结构关系的时相变化 总被引：23，自引：1，他引：23
城市气温与城市下垫面结构的关系,是城市气候研究的关键性课题之一.本文利用1982年在北京市区30个观测点上所测得的春、夏、秋、冬四季昼夜八个时相的气温记录和1983年5月航测的北京市区下垫面资料,用多元回归和逐步回归的方法,对北京城市气温与下垫面结构的关系作了分析.分析结果表明:城市气温和城市下垫面结构中绿地、建筑物、水域三要素的相关程度,随着季节和昼夜的变化而变化.绿地的降温作用以夏季白天为最明显,建筑群的增温作用以冬季夜间为最明显.因为所有测点周围 500m范围内都没有面积较大的水体,各时相气温与水域的相关程度都很小,这清楚地说明:城市内的小面积水体对其周围的气温并没有明显的调剂作用. 相似文献
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徐家堡子地区以黑云英云闪长质片麻岩（２．４７Ｇａ）为围岩的上壳岩（＞２．９８Ｇａ）包体中,发育几条近东西走向的韧性变形变质带（２．７Ｇａ）。研究表明,该韧性变形变质带在平面和剖面上均呈舒缓波状,发育糜棱叶理、矿物线理和Ｓ－Ｃ组构。带内的糜棱片麻岩矿物成分复杂且多世代矿物共存。变形前以石榴石、黑云母、斜长石和石英矿物组合为代表,形成温度为５００～５２０℃,压力为０．４ＧＰａ;韧性变形同期以夕线石、石榴石、石墨、黑云母、斜长石和石英矿物组合为代表,形成温度为６３０～７００℃,压力０．５８～０．７２ＧＰａ;变形期后以十字石、石榴石、斜长石和石英矿物组合为代表,形成温度为５８６℃。形成了一条顺时针演化的ｐＴｔ轨迹。这种复杂的糜棱片麻岩是多期变形变质作用叠加的结果。 相似文献