基于卷积神经网络与条件随机场方法提取乡镇非正规固体废弃物     

刘懿兰  黄晓霞  李红旮  柳泽  陈崇  王新歌 《地球信息科学学报》2019,21(2):259-268

随着村镇经济建设发展,生活垃圾和工业固体废弃物造成的污染问题日益突出,已经成为制约新农村建设发展和生态文明建设的关键问题,而目前针对乡镇非正规固体废弃物的调查与统计主要依赖全国各乡镇相关部门逐级调查上报,工作量较大。本文基于高分辨率遥感影像,将深度学习模型和条件随机场模型相结合引入到乡镇固体废弃物的提取研究中,探索一种基于深度卷积神经网络的乡镇固体废弃物提取模型。由于固体废弃物在影像上表现为面积小,分布破碎等特点,为了提高工作效率,将模型特分为识别和提取2个部分：① 通过全连接卷积网络（CNN）对固体废弃物进行快速识别判断,筛选感兴趣区域影像块;② 在传统的全卷积神经网络(FCN)的基础上加入条件随机场模型(CRF)提取固体废弃物边界,提高整体分割精度。根据安徽、山西等地区相关部门上报固体废弃物堆放点以及住房与城乡建设部城乡规划管理中心进行野外检查的结果,实验最终识别精度达到86.87%以上;形状提取精度为89.84%,Kappa系数为0.7851,识别与提取精度均优于传统分类方法。同时,该方法已经逐步应用于住房和城乡建设部有关成都、兰州、河北等部分乡镇非正规固体废弃物的核查工作,取得了较为满意的结果。  相似文献   

River centerline extraction using the multiple direction integration algorithm for mixed and pure water pixels     

Quanwen Li  Xiaoxia Zhao  Yuming Wu 《地理信息系统科学与遥感》2019,56(2):256-281

The river centerline is a basic hydrological characteristic. Most prior studies have used remote sensing data to extract the river centerline from the open water region in a pure water pixel region. Extracting this type of river is relatively easy. However, extracting the centerline of a micro-river, which is mainly composed of mixed water pixels, is challenging. This paper presents a novel method, called the Multiple Direction Integration Algorithm (MDIA), to extract the river centerline using an image-enhancing method combined with river morphology. MDIA can be applied to regions mainly composed of pure water pixels, as well as to regions consisting of mixed water pixels in the index image. The method first calculates the normalized difference vegetation index (NDVI) and enhances the river linear structure using a Hessian matrix. Second, a small window is constructed as a circular structural element. In the window region, the local threshold is automatically obtained using water-oriented clustering segmentation and prior river knowledge to judge the pixel type. After completing the river centerline extraction in the current window, the next detecting window is generated to continue judgment. The structural element automatically executes river centerline judgment until the entire river centerline is extracted. The Landsat 8 images of six regions with different geomorphologies were chosen to analyze the method’s performance. The test sites include high mountain region, low mountain region, plains region with farmland and a residential region. The experimental results show that the optimal threshold of the processing results ranged from 0.2 to 0.3. In this range, the user’s accuracy is 0.813 to 0.997, and the producer’s accuracy is 0.981 to 1. The MDIA effectively and correctly extracts the river network in mixed-pixel regions. The presented method provides an effective algorithm for river centerline extraction that can be used to expand and update river datasets and provide reliable river centerline data for relevant hydrology studies.  相似文献   

耐压柱壳参数化设计与灵敏度分析     

刘峰  王贺  苗怡然  屠超华  赵彦凯 《海洋技术学报》2019,38(1)

为提高耐压柱壳设计效率,设计了耐压柱壳参数化分析流程。研究了有限元分析所涉及的材料属性、载荷施加、边界条件设置等内容,确定了采用弧长法分析耐压柱壳稳定性。利用Python语言对于ABAQUS软件进行了二次开发,利用Isight软件实现了ABAQUS的集成,实现了耐压柱壳有限元分析模型的网格自动划分、自动分析计算等。选择样本点进行参数化分析,利用响应面模型对于样本点进行了拟合,得到了具有较高拟合精度、满足工程需要的近似模型,进行了设计变量的灵敏度分析。研究结果表明:参数化分析流程可实现耐压柱壳的自动分析、近似模型及灵敏度分析,可降低耐压柱壳分析难度,均可提高耐压柱壳设计效率。  相似文献   

An enhanced underwater camera apparatus for seabed observation of megabenthic epifauna in the northern Yellow Sea     

Yu  Nan  Sun  Song  Wang  Shiwei  Liu  Qun  Zhang  Guangtao  Zhang  Fang  Sun  Xiaoxia 《中国海洋湖沼学报》2020,38(6):1799-1810

Journal of Oceanology and Limnology - Seabed photographing has been applied with various underwater camera apparatuses (UCAs) for observations of megabenthic epifauna, which reveals more details...  相似文献   

对PCM编码式GPS站点布设模式的评价和改进     

邹镇宇  江在森  崔月菊  刘月  刘晓霞 《大地测量与地球动力学》2020,40(4):376-380

本文主要对PCM编码式的布设模式进行分析和改进,介绍PCM编码式和闭锁深度倍数式2种站点布设模式,然后在最小有效距离（MED）为6.31倍断层闭锁深度的情况下,通过精度评价方法对比2种布设模式的结果,发现二者相差不大。进一步研究MED的合理选择,结果表明,MED取20倍的闭锁深度比6.31倍的闭锁深度更为合理。在MED为20倍的情况下对比研究PCM编码式和常规闭锁深度倍数式布设模式的优劣,结果表明,PCM编码式的布设模式优于常规模式。将PCM编码式的布设模式应用于川滇地区的巧家-东川剖面进行检验,发现PCM编码式的结果优于目前站点分布得到的结果,说明合理的站点布设可得到精度更优的结果。本文研究对于断层形变监测中精确获取形变参数具有重要意义。  相似文献   

Characteristics and Origins of Suspended Pyrite in the Mixing Zone of the Yangtze Estuary     

Pang  Yue  Fan  Dejiang  Sun  Xiaoxia  Sun  Xueshi  Liu  Ming  Yang  Zuosheng 《中国海洋大学学报(英文版)》2020,19(4):801-810

For a long time, most studies about pyrite have focused on sediments while only a few have focused on pyrite in water. In this study, a method that combines the scanning electron microscopy(SEM) and the energy dispersive X-ray spectrometry(EDS) was used to compare pyrite particles suspended in water to those in associated bottom sediments, both obtained from the mixing zone of the Yangtze Estuary. It was found that the pyrite particles in the two media have similar morphologies and size distributions. The particle morphology mainly includes two types, single crystal and aggregate, and the particle size mainly ranges from 0.5 to 2 μm. The pyrite particles in water exhibit an increase in relative content towards the sea, and their transport and deposit processes are mainly affected by hydrodynamic conditions. It is concluded that the pyrite particles in the suspended matter mainly derived from the resuspension of sediments, which are products of the early diagenesis. Precursor minerals may appear during the formation of pyrite, but are generally restricted by the diagenetic environment and local microenvironment.  相似文献   

1979～2020年北极和青藏高原臭氧低值区的动力输送特征比较     

王启璐  徐雯雯  涂静怡  于淑洋  饶建  郭栋 《大气科学》2023,(3):866-880

基于ERA5月平均再分析资料,利用Lorenz环流分解方法从定常和瞬变以及基流和涡旋的角度对比了北极与青藏高原臭氧低值区的动力输送特征。结果表明：动力总输送在两地上平流层作用最强,均使其臭氧浓度降低,且定常输送均强于瞬变输送,纬向与经向输送的作用均大致相反。然而,动力输送在北极地区的作用强度远大于青藏高原地区。北极地区纬向输送使得平流层中上层臭氧浓度降低,平流层下层臭氧浓度升高,经向输送的作用与之相反且强度明显偏弱,二者均主要作用于上平流层。青藏高原地区纬向和经向输送除在上平流层均使得臭氧浓度降低外,二者作用大致相反且强度相当,输送大值区在垂直方向上存在双中心结构,分别位于上平流层与上对流层—下平流层（Upper Troposphere–Lower Stratosphere,简称UTLS）区。两地区纬向和经向输送的差异均主要由定常涡旋输送所造成。青藏高原地区定常与瞬变输送的强度差异没有北极地区大。此外,两地定常和瞬变输送中涡旋对臭氧纬向平均的输送均起到主要作用,体现出涡旋输送在两地臭氧浓度变化的动力输送过程中发挥着至关重要的作用。  相似文献   

地质环境信息系统上线安全检测工作实践     

殷铭  武建飞  屠陈子煜  杨宏斌  周萌  韩明伟 《国土资源信息化》2017,(2)

本文针对地质环境领域业务系统的特点,提出了一种信息系统上线安全检测的方法,深入探讨了上线安全检测实践中的基本流程、测评方法与测评成果,为提升地质环境信息系统安全运行和服务能力提供了技术支撑.  相似文献   

Solar Wind and Chromospheric Network     

Marsch  E.  Tu  C.-Y. 《Solar physics》1997,176(1):87-106

A physical model of the transition region, including upflow of the plasma in magnetic field funnels that are open to the overlying corona, is presented. A numerical study of the effects of Alfvén waves on the heating and acceleration of the nascent solar wind originating in the chromospheric network is carried out within the framework of a two-fluid model for the plasma. It is shown that waves with reasonable amplitudes can, through their pressure gradient together with the thermal pressure gradient, cause a substantial initial acceleration of the wind (on scales of a few Mm) to locally supersonic flows in the rapidly expanding magnetic field trunks of the transition region network. The concurrent proton heating is due to the energy supplied by cyclotron damping of the high-frequency Alfvén waves, which are assumed to be created through small-scale magnetic activity. The wave energy flux of the model is given as a condition at the upper chromosphere boundary, located above the thin layer where the first ionization of hydrogen takes place.Among the new numerical results are the following: Alfvén waves with an assumed f ^-1 power spectrum in the frequency range from 1 to ⁴ Hz, and with an integrated mean amplitude ranging between 25 and 75 km s⁴, can produce very fast acceleration and also heating through wave dissipation. This can heat the lower corona to a temperature of 5× 10⁵ K at a height of h=12,000 km, starting from 5× 10⁴ K at h=3000 km. The resulting thermal and wave pressure gradients can accelerate the wind to speeds of up to 150 km s^-1 at h=12,000 km, starting from 20 km s^-1 at h=3000 km in a rapidly diverging flux tube. Thus the nascent solar wind becomes supersonic at heights well below the classical Parker-Type sonic point. This is a consequence of the fact that any large wave-energy flux, if it is to be conducted through the expanding funnel to the corona, implies the building-up of an associated wave-pressure gradient. Because of the diverging field geometry, this might lead to a strong initial acceleration of the flow. There is a multiplicity of solutions, depending mainly on the coronal pressure. Here we discuss two new (as compared with a static transition region model) possibilities, namely that either the flow remains supersonic or slows down abruptly by shock formation, which then yields substantial coronal heating up to the canonical 10⁶ K for the proton temperature.  相似文献   

峨眉山之雨量     

涂长望  许鉴明 《气象学报》1936,12(10):560-573

地理位置欲充分了解峨眉多雨之原因必先明瞭其地理位置。峨眉位北纬二十九度二十八分,东经一○三度四十一分,居四川西南部,去省会成都一五0公里.其山自东高起拔海三0七0公尺,山巅高出峨眉县城二公里,在岷江流域  相似文献