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Taskin Kavzoglu Hasan Tonbul Merve Yildiz Erdemir Ismail Colkesen 《Journal of the Indian Society of Remote Sensing》2018,46(8):1297-1306
Object-based image analysis (OBIA) has attained great importance for the delineation of landscape features, particularly with the accessibility to satellite images with high spatial resolution acquired by recent sensors. Statistical parametric classifiers have become ineffective mainly due to their assumption of normal distribution, vast increase in the dimensions of the data and availability of limited ground sample data. Despite pixel-based approaches, OBIA takes semantic information of extracted image objects into consideration, and thus provides more comprehensive image analysis. In this study, Indian Pines hyperspectral data set, which was recorded by the AVIRIS hyperspectral sensor, was used to analyse the effects of high dimensional data with limited ground reference data. To avoid the dimensionality curse, principal component analysis (PCA) and feature selection based on Jeffries–Matusita (JM) distance were utilized. First 19 principal components representing 98.5% of the image were selected using the PCA technique whilst 30 spectral bands of the image were determined using JM distance. Nearest neighbour (NN) and random forest (RF) classifiers were employed to test the performances of pixel- and object-based classification using conventional accuracy metrics. It was found that object-based approach outperformed the traditional pixel-based approach for all cases (up to 18% improvement). Also, the RF classifier produced significantly more accurate results (up to 10%) than the NN classifier. 相似文献
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In this study,accumulation and distribution of Pb,Cu,Zn,Co,Ni,Mn and Fe in water,bottom sediments and four plant species (Myriophyllum verticillatum,Hydrocharis morsus-ranae,Nymphaea alba and Typha latifolia) were investigated in (C)ernek Lake of Kizihrmak Delta.The Kizdirmak Delta is one of the largest natural wetlands of Turkey and it is protected by the Ramsar convention since 1993.Selected physico-chemical parameters such as pH,conductivity and dissolved oxygen and also trace metal concentrations were monitored in water.All the parameters obtained were found higher than that of the national standards for the protected lakes and reserves.The accumulated amounts of various trace metals in bottom sediments and wetland plants were found in the following order of Fe ＞ Mn ＞ Zn ＞ Ni ＞ Co ＞ Cu ＞ Pb and Fe ＞ Mn ＞ Zn ＞ Ni ＞ Co respectively.The historical trace metal intake of Myriophyllum verticillatum,Hydrocharis morsus-ranae,Typha latifolia and Nymphaea alba were obtained higher than that of the toxic metal levels and these plants may be accepted as accumulators for the detected trace metals and also bioindicators in the historically polluted natural areas. 相似文献
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The aftermath of 2011 Van earthquakes: evaluation of strong motion, geotechnical and structural issues 总被引：1，自引：1，他引：0
Beyza Taskin Atila Sezen Ulgen Mert Tugsal Ayfer Erken 《Bulletin of Earthquake Engineering》2013,11(1):285-312
October 23rd, 2011 M L 6.7 (M w 7.2 KOERI) Tabanli-Van Earthquake caused damage in a widespread area specifically in the settlement regions throughout the Lake Van. A number of 58 buildings totally collapsed during the shake with 52 of them however, reported to be in Ercis district. 17 days after this destructive event, another earthquake of M L 5.6 hit the region again on the 9th of November having the epicentral location at Edremit district. The second earthquake mostly affected the central region of Van province with a number of 25 totally collapsed buildings and furthermore it significantly increased the existing structural damages. Strong motion records from both earthquakes and their impacts on structures as well as geotechnical issues are studied in this paper. Extensive liquefaction triggered lateral spread, landslide and slope failure cases were observed mainly at non-residential areas. Soil amplification is evaluated to be one of the main reasons for the heavy damage occurred in Ercis. Furthermore, site investigations and damage assessment performed after each earthquake proved that the observed damages are strongly correlated with insufficient qualities of structural materials, inadequate detailing and poor workmanship. 相似文献
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Although the M
w
= 6.1 Kovancilar-Turkey earthquake of March 8, 2010 had a moderate intensity with a recorded PGA of 0.07g, it caused heavy damages in 2870 residential buildings having traditional or masonry structural systems and 42 human loss.
Damage has been reported to be particularly concentrated at Kovancilar and Palu counties of Elazig province. Five hours after
this earthquake, an aftershock of M
L
= 5.6 with a PGA of 0.08g struck the same region, developing the existing damages in the structures. In order to investigate this significant amount
of reported damages under the effect of such low ground shakings, our reconnaissance team arrived at the region and unexpectedly
came across a two-story RC building settled on a slope in Yukari Demirci village, which suffered moderate damage during the
shakes. The outline of this paper can be summarized as the presentation of the results of the investigations in the order
of describing the overall observed damages within the region; evaluation of the recorded motions; the details of the field-work
carried out for the two story RC building and the analytical estimation of the site-assessed damages by means of nonlinear
dynamic analysis. Employing the gathered data, the building is analytically modeled as plane frames and analyses are performed
under the effects of the processed earthquake records, which are applied to the structure one after another in the consistent
directions due to the building location. It is shown herein that the structural elements remain in the elastic range subjected
to the processed recorded motions; henceforth acceleration time histories are scaled step by step up to 0.40g and computations are repeated for each acceleration level. Comparison with the observed and the analytically obtained damages
confirmed that approximately 0.30g of peak ground acceleration should have to be exposed during the earthquakes. 相似文献
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Landslide susceptibility mapping using GIS-based multi-criteria decision analysis,support vector machines,and logistic regression 总被引：14，自引：3，他引：11
Identification of landslides and production of landslide susceptibility maps are crucial steps that can help planners, local administrations, and decision makers in disaster planning. Accuracy of the landslide susceptibility maps is important for reducing the losses of life and property. Models used for landslide susceptibility mapping require a combination of various factors describing features of the terrain and meteorological conditions. Many algorithms have been developed and applied in the literature to increase the accuracy of landslide susceptibility maps. In recent years, geographic information system-based multi-criteria decision analyses (MCDA) and support vector regression (SVR) have been successfully applied in the production of landslide susceptibility maps. In this study, the MCDA and SVR methods were employed to assess the shallow landslide susceptibility of Trabzon province (NE Turkey) using lithology, slope, land cover, aspect, topographic wetness index, drainage density, slope length, elevation, and distance to road as input data. Performances of the methods were compared with that of widely used logistic regression model using ROC and success rate curves. Results showed that the MCDA and SVR outperformed the conventional logistic regression method in the mapping of shallow landslides. Therefore, multi-criteria decision method and support vector regression were employed to determine potential landslide zones in the study area. 相似文献
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Saul J. Adelman † Hulya Caliskan Dursun Kocer ‡ Ipek H. Cay H. Gokmen Tektunali ‡ 《Monthly notices of the Royal Astronomical Society》2000,316(3):514-518
Elemental abundances of 28 And (A7 III) and 99 Her (F7 V), which have modest rotational velocities, are derived in a manner consistent with previous studies in this series of papers. The values for 28 And, a δ Scuti variable, show that it is slightly metal-poor, but not a classical Am star. 99 Her, which is somewhat more metal-poor, has a rather small microturbulence for its spectral type. 相似文献
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