A natural language processing and geospatial clustering framework for harvesting local place names from geotagged housing advertisements     

Yingjie Hu  Huina Mao  Grant McKenzie 《International journal of geographical information science》2019,33(4):714-738

Local place names are frequently used by residents living in a geographic region. Such place names may not be recorded in existing gazetteers, due to their vernacular nature, relative insignificance to a gazetteer covering a large area (e.g. the entire world), recent establishment (e.g. the name of a newly-opened shopping center) or other reasons. While not always recorded, local place names play important roles in many applications, from supporting public participation in urban planning to locating victims in disaster response. In this paper, we propose a computational framework for harvesting local place names from geotagged housing advertisements. We make use of those advertisements posted on local-oriented websites, such as Craigslist, where local place names are often mentioned. The proposed framework consists of two stages: natural language processing (NLP) and geospatial clustering. The NLP stage examines the textual content of housing advertisements and extracts place name candidates. The geospatial stage focuses on the coordinates associated with the extracted place name candidates and performs multiscale geospatial clustering to filter out the non-place names. We evaluate our framework by comparing its performance with those of six baselines. We also compare our result with four existing gazetteers to demonstrate the not-yet-recorded local place names discovered by our framework.  相似文献   

Polar shapelets     

Richard Massey  Alexandre Refregier 《Monthly notices of the Royal Astronomical Society》2005,363(1):197-210

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基于中间件的遥感影像数据共享技术研究     

王连备 《测绘工程》2009,18(5):51-54

针对遥感影像共享服务的应用需求,提出基于中间件技术的影像数据共享方法;设计基于中间件技术的影像数据服务模式。通过实验实现支持多用户并发访问的服务原型,验证基于中间件技术的影像数据服务方法的可行性并给出进一步研究的方向。  相似文献   

Wavelet Analysis of Space Solar Telescope Images   总被引：1，自引：0，他引：1  

Xi-An Zhu  Sheng-Zhen Jin  Jing-Yu Wang  Shu-Nian NingNational Astronomical Observatories  Chinese Academy of Science  Beijing  Department of Mechanical  Electric Engineering  China College of Mining  Technology  Beijing 《中国天文和天体物理学报》2003,3(6):587-596

The scientific satellite SST (Space Solar Telescope) is an important research project strongly supported by the Chinese Academy of Sciences. Every day, SST acquires 50 GB of data (after processing) but only 10GB can be transmitted to the ground because of limited time of satellite passage and limited channel volume. Therefore, the data must be compressed before transmission. Wavelets analysis is a new technique developed over the last 10 years, with great potential of application. We start with a brief introduction to the essential principles of wavelet analysis, and then describe the main idea of embedded zerotree wavelet coding, used for compressing the SST images. The results show that this coding is adequate for the job.  相似文献   

厚片CCD的数据转换及初步分析     

吴光节 《天文研究与技术》1992,(3)

云台厚片CCD光谱系统自建立以来,基本上还只是一个封闭的系统:储存在5吋软盘中的数据只能在该系统的计算机中读出和简单处理,但该系统的计算机硬件和软件均不能满足现代光谱处理的要求。本文在将厚片CCD光谱资料转换到VAX计算机的基础上,对资料转换及其必要性以及该光谱系统的硬、软件配置进行了初步的分析与讨论。  相似文献   

Shapelets – I. A method for image analysis     

Alexandre Refregier 《Monthly notices of the Royal Astronomical Society》2003,338(1):35-47

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Shapelets – II. A method for weak lensing measurements     

Alexandre Refregier  David Bacon 《Monthly notices of the Royal Astronomical Society》2003,338(1):48-56

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Real-time difference imaging analysis of MOA Galactic bulge observations during 2000     

I.A. Bond  F. Abe  R.J. Dodd  J.B. Hearnshaw  M. Honda  J. Jugaku  P.M. Kilmartin  A. Marles  K. Masuda  Y. Matsubara  Y. Muraki  T. Nakamura  G. Nankivell  S. Noda  C. Noguchi  K. Ohnishi  N.J. Rattenbury  M. Reid  To. Saito  H. Sato  M. Sekiguchi  J. Skuljan  D.J. Sullivan  T. Sumi  M. Takeuti  Y. Watase  S. Wilkinson  R. Yamada  T. Yanagisawa  P.C.M. Yock 《Monthly notices of the Royal Astronomical Society》2001,327(3):868-880

We describe observations carried out by the MOA group of the Galactic bulge during 2000 that were designed to detect efficiently gravitational microlensing of faint stars in which the magnification is high and/or of short duration. These events are particularly useful for studies of extrasolar planets and faint stars. Approximately 17 deg² were monitored at a sampling rate of up to six times per night. The images were analysed in real time using a difference imaging technique. 20 microlensing candidates were detected, of which eight were alerted to the microlensing community whilst in progress. Approximately half of the candidates had high magnifications (≳10), at least one had very high magnification (≳50), and one exhibited a clear parallax effect. The details of these events are reported here, together with details of the on-line difference imaging technique. Some nova-like events were also observed and these are described, together with one asteroid.  相似文献   

抗差估计的初值选择     

王振杰  欧吉坤  曲国庆 《大地测量与地球动力学》2001,21(3):32-35

对L1 范估计的平差值和LS估计的平差值作为抗差估计的初值进行了比较 ,指出在 ρ函数是严凸函数时 ,二者无明显的区别。因为LS估计简单且易于计算 ,因此建议用LS估计的平差值作为抗差估计的初值。  相似文献   

Particle-mesh simulations of the Lyα forest     

Avery Meiksin  Martin White 《Monthly notices of the Royal Astronomical Society》2001,324(1):141-148

We have analysed short-exposure high-resolution images obtained on the William Herschel Telescope (WHT), Big Telescope Azimuthal (BTA) and CanadaFranceHawaii Telescope (CFHT) in order to investigate mechanical vibrations that are capable of reducing the high angular resolution allowed by speckle-interferometric methods. After filtering the photon noise we have computed power spectra of the image centres of gravity. In these spectra we have found vibration features that differ from one telescope to another and that vary in particular with the zenith angle. In the case of the WHT we discuss these results in terms of possible causes and in terms of degradation of the transfer function. We present some means to improve the data.  相似文献