Astrometric Solution of the Multiple System Xy Leo

An astrometric solution, together with time of minimum analysis, has been made for the multiple system XY Leonis (HIP 49136) to identify the properties of the remote companion to the eclipsing pair (AB). From this solution, we derive the inclination of the wide orbit (AB-cd) as 94.4^∘± 0.2^∘, angle of nodes as 247.3^∘± 0.2^∘, and the mass of the wide component (the dwarf binary cd) as 0.98 ± 0.2 M_⊙. This study confirms that the light travel time effect can explain the sinusoidal O−C variation of the eclipsing system.     

First Ground-Based Photometry and Light Curve Analysis of the Recently Discovered Contact Binary Hx Uma

Photoelectric UBV light curves of the recently discovered eclipsing binary HX UMa were obtained and studied to determine the preliminary physical parameters of the system for the first time. The observations were taken at the TüBİTAK¹ – Turkish National Observatory (TUG) on three nights in April 2003. A simultaneous analysis of the light and radial velocity curves yields a typical A-type contact binary with a high degree of overcontact. The influence of the close visual companion to the total light of the system was taken into account during the analysis. ¹TüBİTAK: The Scientific and Technical Research Council of Turkey.     

Image classification-based ground filtering of point clouds extracted from UAV-based aerial photos

With the advent of unmanned aerial vehicles (UAVs) for mapping applications, it is possible to generate 3D dense point clouds using stereo images. This technology, however, has some disadvantages when compared to Light Detection and Ranging (LiDAR) system. Unlike LiDAR, digital cameras mounted on UAVs are incapable of viewing beneath the canopy, which leads to sparse points on the bare earth surface. In such cases, it is more challenging to remove points belonging to above-ground objects using ground filtering algorithms generated especially for LiDAR data. To tackle this problem, a methodology employing supervised image classification for filtering 3D point clouds is proposed in this study. A classified image is overlapped with the point cloud to determine the ground points to be used for digital elevation model (DEM) generation. Quantitative evaluation results showed that filtering the point cloud with this methodology has a good potential for high-resolution DEM generation.     

Performance of Core Strangle Test (CST) on Porous Rocks

The Core Strangle Test (CST) has been proposed in 2009 by author as an index test permitting indirect estimation of the Uniaxial Compressive Strength. In this test, load is applied through a circle perpendicular to the core axis as a strangle. The mentioned advantage of the experiment is the possibility of testing quite short rock cores on which the UCS experiment cannot be performed. In the original paper published at 2009, the author performed several experiments on non-porous rocks on which the UCS has also been measured. The results showed a linear correlation between the UCS and the CST index permitting an indirect evaluation of the UCS by performing CST experiments. The current paper is quite similar to the original paper with the difference that the experiments are performed here on porous rocks of various porosity. CST and UCS of the rocks are shown to have both exponential correlations with the rock porosity. Once again a linear relation, quite close to the one in the original paper, is obtained for the UCS of the porous rocks as a function of the CST index. This study confirms that the CST experiment can also be used for porous rocks. Studying the feasibility of CST method on porous rocks seems to be a logical next step in the development of this experiment and the results clearly support it.     

The comparison of the performance of ELM,BRNN, and SVM methods for the prediction of compression index of clays

The compression index (Cc) is a necessary parameter for the settlement calculation of clays. However, determination of the compression index from oedometer tests takes a relatively long time and leads to a very demanding experimental working program in the laboratory. Therefore, geotechnical engineering literature involves many studies based on indirect methods such as multiple regression analysis (MLR) and soft computing methods to determine the compression index. This study is aimed to predict the compression index by using extreme learning machine (ELM), Bayesian regularization neural network (BRNN), and support vector machine (SVM) methods. The selected variables for each method are the natural water content (w_n), initial void ratio (e₀), liquid limit (LL), and plasticity index (PI) of clay samples. Many trials were carried out in order to get the best prediction performance with each model. The application results obtained from the models were also compared based on the correlation coefficient (R), coefficient of efficiency (E), and mean squared error (MSE). The results indicate that the BRNN method has better success on estimation of the compression index compared to the ELM and SVM methods.     

Temporal monitoring of water level changes in Seyfe Lake using remote sensing

The Earth's water resources are endangered by inconsiderate use, pollution and lack of conservation measures. Temporal monitoring is necessary for the conservation and usage planning of water resources and to make informed decisions. Seyfe Lake and its environs in Turkey is one of the most important water basins in the world, because it is a node on bird migration paths between Europe, Asia and Africa. For this reason, the International Council of Bird Preservation (ICBP) has registered 27 of the bird species living at Seyfe Lake on the conservation list. In this work, the temporal changes in the water surface area of Seyfe Lake and its environs, which are important for ecological, historical and tourism reasons, are investigated. The change of water surface in the lake is examined over a 26 year period using satellite images taken between 1975 and 2001. Landsat images from years 1975, 1987 and 2001 are used. The change is tracked from the images using an unsupervised classification method. A decrease of slightly more than 33% was observed in the water surface area this 26 year period. The temporal change indicated by the images was compared with the related meteorological data between 1975 and 2001. Over this time period, climate conditions (rainfall, temperature and evaporation) in the study area have been changed by approximately 21%. These changes could have affected the Lake surface area, but so also could external human interference around the Lake. Copyright © 2008 John Wiley & Sons, Ltd.     

Generation of Bianchi Type V Universes Filled with A Perfect Fluid

Assuming a perfect fluid distribution of matter Bianchi type Vspace-time is considered and using a new generation techniqueit is shown that the field equations are solvable for anyarbitrary cosmic scale function. Solutions for particularforms of cosmic scale functions are obtained, and thegeometrical and physical properties of these solutions discussed.     

A small-scale landslide susceptibility assessment for the territory of Western Carpathians

This study presented herein compares the bivariate and multivariate landslide susceptibility mapping methods and presents the landslide susceptibility map of the territory of Western Carpathians in small scale. This study also describes pioneer work for the territory of Western Carpathians, overreaching state borders, using verified sophisticated statistical methods. In the susceptibility mapping, digital elevation model was first constructed using a GIS software, and parameter maps affecting the slope stability such as geology, seismicity, precipitation, topographical elevation, slope angle, slope aspect and land cover were considered. In the last stage of the analyses, landslide susceptibility maps were produced using bivariate and multivariate analyses, and they were then compared by means of their validations. The validation of the bivariate analysis data was performed using the results of bivariate analysis for landslide areas of Slovakia containing five classes of susceptibility in scale 1:500,000. The validation area is the area of Western Carpathians within Slovakia. Eighty-two per cent of area does not differ in more than one class. The validation of the multivariate analysis data was performed using the results from the Kysuce region in the northern part of Slovakia in scale 1:10,000. The raster calculator was used to express the difference between each pair of pixels within these two layers. Seventy-seven per cent of the pixels do not differ in more than 25 %, 94 % of the pixels do not differ in more than 50 %. The maximal possible difference is 100 % (one pixel with value 0 and other with value 1, or vice versa). Receiver operating characteristic analysis was also performed, the area under curve value for bivariate model was calculated to be 0.735, while it was 0.823 for multivariate. The results of the validation can be considered as satisfactory.     

Monitoring of soil erosion in Cappadocia region (Selime-Aksaray-Turkey)

A fairy chimney is a conical rock formation, typically found in the Cappadocia region of Turkey. The geology of areas where fairy chimneys exist typically comprise a thick layer of tuff, covered by a thin layer of basalt or other volcanic rocks that are more resistant to erosion than the underlying tuff. Fairy chimneys are formed where a small cap or boulder of the original basalt remains, protecting a cone of tuff beneath it from erosion. Eventually, the tuff will be undercut to the extent that the cap falls off, and the remaining cone is then quickly eroded. In this study, the formation of fairy chimneys in the Cappadocia region was examined by investigating the surface soil erosion. A study area was selected and then scanned at five different times by a geodetic robotic total station at 40 cm horizontal and vertical intervals. The volumes of the study area were calculated from the same height and erosion was calculated from the volume differences indicated by the data. The relationship between erosion and meteorological data was analyzed, and showed that erosion had increased due to climatic conditions, particularly from the effect of rainfall.