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Öğe A ROBUST APPROACH FOR DETERMINING ROTATIONAL LANDSLIDE AREA FROM TWO EPOCHS OF LIDAR DATA(STEF92 TECHNOLOGY LTD, 2016) Celik, Cahit TagiLight Detection and Ranging (LiDAR) System has been a powerful tool to acquire three dimensional positions and intensity of a returned signal from a reflecting object. With accurate positioning data, determining and monitoring deformations including dynamics and kinematics of the Earth crust can be possible. One of the deformations is a landslide. Detecting and monitoring of them are important in understanding the behavior of the Earth crust and preventing a possible hazard that may occur. Landslide detection is, therefore, one of the areas where studies being carried out. In this paper, a robust approach for detecting rotational type landslides by using two epochs of LiDAR data was proposed; one before and one after landslide occurred. The proposed method was based on outlier detection using whiskers plot of height differences obtained for an area profiled along the maximum slope direction. The gridded area was then handled in profile fashion imposing particular conditions that meet the properties of a rotational landslide. To test the proposed approach, two epochs of LiDAR data used first epoch of which is a real LiDAR data and second epoch of which is a simulated data to ensure the data contained one or more landslides. The preliminary results presented showed that the proposed approach was capable of detecting rotational type of landslides. This study may be important for those studying landslides in more detail.Öğe Accuracy investigation of height obtained from Classical and Network RTK with ANOVA test(ELSEVIER SCI LTD, 2016) Gumus, Kutalmis; Selbesoglu, Mahmut Oguz; Celik, Cahit TagiTo assess the accuracy of vertical components obtained by Classical RTK and Network Real Time Kinematic positioning with different correction methods with setting of different number of epoch, height differences obtained from precise geometric leveling was used as reference height differences along with those obtained from static GPS only solutions, and combined solutions of GPS and GLONASS on different GNSS days. One-way variance analysis (ANOVA) were applied to the height differences to test them whether they are significantly different or not. The significant differences, if any, were further tested by using Post Hoc test to reveal the effects of the method used, the epoch number, or the measuring time, which is responsible for the significant differences. The results from ANOVA showed that the number of epoch had not much effect on the vertical components but on the correction methods. MAC method presented the most deviated results compared to the other methods with different GNSS days' solutions. In general, VRS method was found to be the most consistent method among others used. This study is important in both; an accuracy assessment with respect to the most precise method in heights (i. e., precise geometric leveling) was carried. The techniques (ANOVA and Post Hock Test) used in the accuracy assessment. (C) 2016 Elsevier Ltd. All rights reserved.Öğe ANALYTICAL NOISE CONTOUR CONSTRUCTION USING INVERSE SQUARE LAW OF SOUND PROPAGATION(GH ASACHI TECHNICAL UNIV IASI, 2008) Celik, Cahit Tagi; Guremen, LaleOne of the most important environmental problems is traffic noise in urban areas. In order to assess and monitor its influence on environmental quality, road traffic noise measurements are necessary. In generation of noise contour map, two main problems are encountered: noise measurements, which take considerable amount of time, and the method for rigorous production of noise contour map. An extrapolation technique was developed to construct noise contours using actual sound level measurements and GPS coordinates in connection with GIS. This technique was applied to the road traffic noise level measurements performed at 61 stations on the main roads and roundabouts of Nigde city of Turkey in 5.5 km(2) area having approximately 100,000 inhabitants. Production of reliable noise contour map of Nigde was presented by using developed extrapolation technique, which utilize inverse square law of sound propagation.Öğe FINDING AN APPROPRIATE METHOD FOR SMALL-SCALE SURVEYING APPLICATION AMONG REAL TIME SATELLITE-BASED METHODS IN TURKEY(UNIV OSIJEK, TECH FAC, 2013) Gumus, Kutalmis; Celik, Cahit Tagi; Koc, IbrahimIn this paper, for small-scale surveying applications, investigation of appropriate methods among classical RTK, net-RTK which provides Virtual Reference Station (VRS), and Fl chen-Korrektur Parameter (FKP) corrections were performed. A test network consisting of 56 stations has been established in Istanbul. Measurements were carried out using the above methods. Five separate tests were applied on the coordinates obtained by the methods. The results showed that the methods from the most accurate to the least accurate one were classical RTK, Net-RTK-VRS and Net-RTK-FKP. In general, horizontal components were found to be two times better than vertical components ranging from 1 mm to approximately 5 cm.Öğe INVESTIGATION OF ACCURATE METHOD IN 3-D POSITION USING CORS-NET IN ISTANBUL(UNIV FEDERAL PARANA, CENTRO POLITECNICO, 2012) Gumus, Kutalmis; Celik, Cahit Tagi; Erkaya, HalilIn this study, for Istanbul, there are two Cors Networks (Cors-TR, Iski Cors) providing Virtual Reference Station (VRS), and Flachen Korrektur Parameter (FKP), corrections to rover receiver for determining 3-D positions in real time by Global Positioning System (GPS). To determine which method (or technique) provides accurate method for position fixing, a test network consisting of 49 stations was set up in Yildiz Technical University Davudpasa Campus. The coordinates of the stations in the test network were determined by conventional geodetic, classical RTK, VRS and FKP methods serviced by both Cors-TR and Iski Cors. The results were compared to the coordinates by the conventional method by using total station. The results showed a complex structure as the accuracy differs from one component to another such as in horizontal coordinates, Y components by CorsTR_VRS and Cors_TR_FKP showed 'best' results while the same technique provided X components consistent accuracy with the Y component but less accurate than by real time kinematic (RTK). In vertical components, of all the techniques used for the h components, CorsTR_VRS showed 'best' accuracy with three outliers.Öğe Performance of ANN in determination of unstable points in leveling networks(ACADEMIC JOURNALS, 2010) Celik, Cahit TagiDeformation analysis is important for a man-made structure or a natural phenomenon like crustal movement, vertical land movements, subsidence determination, etc. Deformation analysis generally depends upon determination of stable and unstable points relative to a reference network assumed to be located outside the movement area. However, a reference network itself needs to be assured free from movements. This can be achieved conventionally by using a single point movement test. The accuracy of the results depends on the method used. This study recommends a new method of detecting stable and unstable points in a reference network designed for vertical movements. The method is based on an artificial neural network (ANN) which also enables one to measure the validity of performance of conventional method aiming at the determination of unstable points in a reference network. The presented results showed that the ANN is capable of determining unstable and stable points in a one-dimensional surveying network.Öğe PERFORMANCE OF ARTIFICIAL NEURAL NETWORKS ON KRIGING METHOD IN MODELING LOCAL GEOID(UNIV FEDERAL PARANA, CENTRO POLITECNICO, 2013) Akcin, Hakan; Celik, Cahit TagiTransformation of ellipsoidal heights determined by satellite techniques into local leveling heights requires geoid heights at points of interest. However, the geoid heights at each point are not available. In order to determine them, the local geoid in the transformation area must be modeled or computed by an appropriate method, one way of doing it, is to use control points both of whose ellipsoidal and local leveling heights are available. In this study, performance of geoid by ANN compared to Kriging method in modeling local geoid was presented. Moreover, the transformation ability of the methods was investigated through a geodetic test network in Bursa Metropolitan Area of Turkey. The results suggest that the model by ANN exhibit better results than the one by Kriging Method.Öğe PERFORMANCE OF FUZZY LOGIC IN DETERMINATION OF UNSTABLE POINTS IN LEVELING NETWORKS.(INT SCIENTIFIC CONFERENCE SGEM, 2010) Celik, Cahit TagiA man-made structure or natural phenomena like crustal movement, vertical land movements, subsidence determination, etc. is subject to deformations due to forces on them. Deformations of a structure require rigorous analysis to reflect significant movements. In general, deformation analysis relies on the reference network that is set outside the deforming area so that a comparison could be possible. However, a geodetic reference network is itself subject to movement. Therefore, the stability of the reference network needs to be conformed by some suitable methods. There exist a number of methods for performing the determination of stable and unstable points in the reference network. In this study, based on the fuzzy logic algorithm, a new method of detecting stable and unstable points in a reference network designed for detection of vertical movements is recommended. To test the proposed method a simulation was carried out and the results were presented.Öğe SEGMENTATION BY FOURIER TRANSFORMATION FOR LANDSLIDE DETECTION FROM LIDAR DATA(STEF92 TECHNOLOGY LTD, 2013) Celik, Cahit Tagi; Grejner-Brzezinska, Dorota; Toth, CharlesDetermination of deformations is important to understanding the characteristics of the body or mass under investigation, including deformations of natural structures, such as crustal movements, landslides, as well as man-made objects, such as dams, large bridges, viaducts, buildings, etc. Determination of landslides can be performed by different techniques including Light Detection And Ranging (LiDAR). LiDAR is a relatively new technique for determination of landslides and, consequently, a number of issues related to that problem remain unsolved or is partially solved. One of them is the segmentation problem. This paper aims at proposing a segmentation solution for landslide determination from two sets of LiDAR data for the same area, acquired at different times. In this process, Fourier Transformation is used to determine the maximum changes in the surfaces. The data used in this work include one set of real LiDAR measurements for the first (reference) epoch, and simulated data for the second epoch, where landslide effects are superimposed in a small range within the area covered by the data from the reference epoch. The results are presented and it is shown that the technique can be efficiently used in the segmentation stage.Öğe Segmentation by fourier transformation for landslide detection from lidar data(International Multidisciplinary Scientific Geoconference, 2013) Celik, Cahit Tagi; Grejner-Brzezinska, Dorota; Toth, CharlesDetermination of deformations is important to understanding the characteristics of the body or mass under investigation, including deformations of natural structures, such as crustal movements, landslides, as well as man-made objects, such as dams, large bridges, viaducts, buildings, etc. Determination of landslides can be performed by different techniques including Light Detection And Ranging (LiDAR). LiDAR is a relatively new technique for determination of landslides and, consequently, a number of issues related to that problem remain unsolved or is partially solved. One of them is the segmentation problem. This paper aims at proposing a segmentation solution for landslide determination from two sets of LiDAR data for the same area, acquired at different times. In this process, Fourier Transformation is used to determine the maximum changes in the surfaces. The data used in this work include one set of real LiDAR measurements for the first (reference) epoch, and simulated data for the second epoch, where landslide effects are superimposed in a small range within the area covered by the data from the reference epoch. The results are presented and it is shown that the technique can be efficiently used in the segmentation stage. © SGEM2013 All Rights Reserved by the International Multidisciplinary Scientific GeoConference SGEM.
