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Han N.-L.,Beijing Normal University | Han N.-L.,Center for Assessment and Development of Real Estate | Liu C.,Beijing Normal University | Zhuang L.,Beijing Normal University | Zhang W.,CAS Shenzhen Institutes of Advanced Technology
Jilin Daxue Xuebao (Diqiu Kexue Ban)/Journal of Jilin University (Earth Science Edition) | Year: 2012

It is important to remove cloud in the CCD images of satellite for enhancing and extracting remote sensing information, especially in low latitude areas. In order to remove thin cloud in the CBERS-02B CCD images, two different forms of wavelet transforms were used. Low-frequency coefficients that are decomposed by two wavelet transforms are processed by homomorphic filter separately for lowing its low-frequency information. Results is reconstructed with low-frequency coefficients and high-frequency coefficients which decomposed from Mallat and à trous wavelet transform. According to quantitative evaluation, à trous wavelet transform combining with homomorphic filter algorithm can produce good results in thin cloud removal with higher entropy and standard deviation. It also can retain a large amount of information and rich detail information. Source


Chong X.,Center for Assessment and Development of Real Estate | Li S.,National Bureau of Statistics Survey Office in Shenzhen
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015

This paper introduces a 3D city simulation system which is based on geographic information system (GIS), covering all commercial housings of the city. A regional- scale, GIS-based approach is used to capture, describe, and track the geographical attributes of each house in the city. A sorting algorithm of "Benchmark + Parity Rate"? is developed to cluster houses with similar spatial and construction attributes. This system is applicable for digital city modeling, city planning, housing evaluation, housing monitoring, and visualizing housing transaction. Finally, taking Jingtian area of Shenzhen as an example, the each unit of 35,997 houses in the area could be displayed, tagged, and easily tracked by the GIS-based city modeling and simulation system. The match market real conditions well and can be provided to house buyers as reference. © 2015 SPIE. Source


Yao L.,Harbin Institute of Technology | Yao L.,Center for Assessment and Development of Real Estate | Liu Q.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Liu G.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research
Communications in Computer and Information Science | Year: 2016

While remote sensing and geographic information systems have been used successfully to classify forest health using recent image, applying this process to older images is problematic because contemporaneous field data are not available to measure the accuracy of the classification of historical images. Data ranges of normalized difference water index(NDWI) were established for each Robinia Pseudoacacia health class using a contemporary image and field data by sequential cluster analysis. These ranges were used to separate Landsat Thematic Mapper (TM) images acquired from 1999 to 2007 into a series of health-class maps, By applying cross-tabulation procedures to pairs of classified images, we can see how the Robinia Pseudoacacia health class of each pixel in the images of the study area had changed over time. The resulting maps provide a look back at forest conditions of the past and can be used to identify areas of special interest. Further analysis carried out between environmental factors(soil salt, soil texture, soil type, DEM, groundwater depth and groundwater salinity)and the Robinia Pseudoacacia health led to identify the likely causes of these negative trends. © Springer-Verlag Berlin Heidelberg 2016. Source


Liu G.-N.,China Academy of Railway Sciences | Hu R.-H.,Center for Assessment and Development of Real Estate | Pan X.-H.,First Branch of Shenzhen Municipal Land | Liu Y.-C.,China Academy of Railway Sciences
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2013

The sheet pile wall with relieving platform is a new type of retaining structure. It is more convenient in construction and has lower cost and nicer shape than the pile-supported cantilever retaining wall and the pile-supported pre-stressed cable anchor retaining wall. Because of its particularity, complexity and existing variable factors, the mechanical behaviors of this structure is unclear. Therefore, based on the similarity theory, taking its general structure form as the prototype, through multiple sets of model tests with geometrical proportion of 7:1, the earth pressure distribution mode of the structure is studied. The test results show that: (1) the earth pressure is zero under the reliving platform; (2) it is recommended to use the m method to calculate the resistance in piles; and (3) the calculation mode should be the stress pattern and earth pressure of the overall structure. Source


Liu W.,Tsinghua University | Guo H.,Tsinghua University | Li H.,Hong Kong Polytechnic University | Li Y.,Center for Assessment and Development of Real Estate
International Journal of Advanced Robotic Systems | Year: 2014

More and more mega-complex bridge projects are being or will be built worldwide. At the same time, the design and construction of such projects involve more and more challenges, e.g., complex structural designs, complicated construction environments, etc. This research study aims to apply BIM (Building Information Modelling) to bridge projects to improve the efficiency and effectiveness of design and construction. Through the analysis of the characteristics of bridge projects and relevant, associated problems, a BIM-based solution to improving design and construction is developed, including conceptual design optimization, detailed design optimization, the optimization of construction sequences, construction scheduling, construction management, and construction process monitoring. Furthermore, a real-life bridge project is presented to demonstrate the feasibility and validity of the BIM-aided approach to design and construction. It is shown that BIM has the potential to improve the design and construction of bridge projects. It is expected that this research could contribute to the extensive application of BIM in mega-complex bridge projects to aid in design and construction in the future. © 2014 The Author(s). Source

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