Piyer Loti'nin İstanbul resimleri sergilendi

Taha Toros Arşivi, Dosya Adı: Pierre Lotiİstanbul Kalkınma Ajansı (TR10/14/YEN/0033) İstanbul Development Agency (TR10/14/YEN/0033

Photogrammetric deformation monitoring of the second Bosphorus Bridge in Istanbul

Improving the efficiency of bridge inspection and minimizing the impact of dynamic load on the long term deterioration of the bridge structure reduces maintenance and upkeep costs whilst also improving bridge longevity and safety. This paper presents the results of an on-going project whose ultimate goal is the real-time photogrammetric monitoring the structural deformations of the second Bosphorus Bridge of Istanbul.Publisher's Versio

Investigation of the effect of bending twisting coupling on the loads in wind turbines with superelement blade definition

Bending-twisting coupling in the composite blades is exploited for load alleviation in the whole turbine system. For the purpose of the study, inverse design of a reference blade is performed such that sectional beam properties of the 3D blade design approximately match the sectional beam properties of NREL's 5MW turbine blade. In order to appropriately account for the bending-twisting coupling effect, dynamic superelement of the blade is created and introduced into the multi-body dynamic model of the wind turbine system. Initially, a comparative study is conducted on the performance of wind turbines which have blades defined as superelements and geometrically nonlinear beams, and conclusions are inferred with regard to the appropriateness of the use of superelement blade definition in the transient analysis of the 5MW wind turbine system that is set up in the present study. Multi-body dynamic simulations of the wind turbine system are performed for the power production load case with the constant wind and the normal turbulence model as external wind loadings. For the internal loads, fatigue damage equivalent load is used as the metric to assess the effect of bending-twisting coupling on the load alleviation in the whole wind turbine system. Results show that in the overall, through the bending-twisting coupling induced with the use of off-axis plies in the main spar caps of the blade, damage equivalent loads associated with the critical load components can be reduced in the wind turbine system

Investigation of Preservice Science Teachers’ Comprehension of the Star, Sun, Comet and Constellation Concepts

The purpose of this study is to reveal preservice science teachers’ perceptions related to the sun, star, comet and constellation concepts. The research was carried out by 56 preservice science teachers (4 th grade) at Kastamonu University taking astronomy course in 2014-2015 academic year. For data collection open-ended questions that required defining, drawing and association of concepts was used. Data was collected in two stages before and after relevant concepts were taught. The collected data were analyzed using different rubrics. It is seen that preservice teachers’ insufficient knowledge, alternative ideas and figures away from scientific knowledge about star, sun, constellation and comet concepts that determined in pre-test showed a showed a decrease in post-test. Besides, even though there is an increase in star concept-sun, constellation and comet concept associations in post-test in comparison with pre-test, it is understood that some ideas of preservice teachers remained the same. In the light of the results, it is thought that learners are being inexperienced in astronomy, it is required to benefit from teaching materials such as three dimensional models, conceptual change texts, telescope, etc. in teaching basic astronomy concepts. Keywords: star, sun, comet, constellation, student comprehensio

The Effect of the Size of Traffic Analysis Zones on the Quality of Transport Demand Forecasts and Travel Assignments

In this work we have studied the selection criteria for traffic analysis zones and the effects of their size and number on the model’s forecasting capabilities. To do so we have focused on the corridor of İstanbul’s Kadıköy-Kartal Metro Line and evaluated the consistency of demand forecasts and travel assignments versus actual measurements under different sizes of the Traffic Analysis Zones (TAZ). Significant improvements in model accuracy were observed by decreasing the zone size. Specifically, studying the public transport network assignments for the metro line when increasing the number of traffic analysis zones from 540 to 1,788 the root mean square error (RMSE) of forecasted vs. actual station-based counts was reduced by 23%. Subsequently, the study used population density and employment density as independent variables for the determination of the optimal radius for the 1,788 zone area, and applied an exponential regression model. Appropriate model parameters were derived for the above case study. The regression model resulted in R2 values over 0.62

Total least squares registration of 3D surfaces

Co-registration of point clouds of partially scanned objects is the first step of the 3D modeling workflow. The aim of coregistration is to merge the overlapping point clouds by estimating the spatial transformation parameters. In computer vision and photogrammetry domain one of the most popular methods is the ICP (Iterative Closest Point) algorithm and its variants. There exist the 3D Least Squares (LS) matching methods as well (Gruen and Akca, 2005). The co-registration methods commonly use the least squares (LS) estimation method in which the unknown transformation parameters of the (floating) search surface is functionally related to the observation of the (fixed) template surface. Here, the stochastic properties of the search surfaces are usually omitted. This omission is expected to be minor and does not disturb the solution vector significantly. However, the a posteriori covariance matrix will be affected by the neglected uncertainty of the function values of the search surface. . This causes deterioration in the realistic precision estimates. In order to overcome this limitation, we propose a method where the stochastic properties of both the observations and the parameters are considered under an errors-in-variables (EIV) model. The experiments have been carried out using diverse laser scanning data sets and the results of EIV with the ICP and the conventional LS matching methods have been compared.Publisher's Versio

Co-registration of 3d point clouds by using an errors-in-variables model

Co-registration of point clouds of partially scanned objects is the first step of the 3D modeling workflow. The aim of co-registration is to merge the overlapping point clouds by estimating the spatial transformation parameters. In the literature, one of the most popular methods is the ICP (Iterative Closest Point) algorithm and its variants. There exist the 3D least squares (LS) matching methods as well. In most of the co-registration methods, the stochastic properties of the search surfaces are usually omitted. This omission is expected to be minor and does not disturb the solution vector significantly. However, the a posteriori covariance matrix will be affected by the neglected uncertainty of the function values. This causes deterioration in the realistic precision estimates. In order to overcome this limitation, we propose a new method where the stochastic properties of both (template and search) surfaces are considered under an errors-in-variables (EIV) model. The experiments have been carried out using a close range laser scanning data set and the results of the conventional and EIV types of the ICP matching methods have been compared.Publisher's Versio

Mizahın “haha”sı ile öğrenmenin “aha”sı arasındaki derin ilişki: Bağlam temelli çizgi roman geliştirilmesi, öğretmen ve öğrenci görüşleri

The research aimed to determine the opinions of the students and the course teacher with regard to using the comic book prepared in accordance with a context-based scenario as teaching material for the science course. Phenomenology, one of the qualitative research approaches, was used for research purposes. A context-based comic book was used as course material for 12 hours in a class of 18 5th-grade students. Semi-structured interviews were conducted with seven students and a course teacher, following the implementation, using the interview forms developed within the scope of the current research. The data obtained from the interviews were analyzed by content analysis and classified under the themes of “Academic”, “Affective”, “Association with Daily Life” and “Comic Books and Humor”. Pursuant to the results of the research, students, and course teacher declared the comic book as effective course material on the grounds that it makes the subject matter entertaining and understandable, facilitates learning, provides an opportunity for a permanent learning experience, provides an opportunity for individual learning, increases class participation, and supports the learning processes of students with literacy and language problems. Based on the results obtained, it has been suggested to use context-based comics in different units and lessons.Araştırmada fen bilimleri dersine yönelik bağlam temelli bir senaryoya göre hazırlanan çizgi romanın öğretim sürecinde kullanılmasıyla ilgili olarak öğrencilerin ve ders öğretmeninin görüşlerinin belirlenmesi amaçlanmıştır. Çalışmada, nitel araştırma yaklaşımlarından olgubilim deseni kullanılmıştır. Araştırmada bağlam temelli hazırlanan çizgi roman, 5. sınıfta öğrenim gören 18 öğrencinin bulunduğu sınıfta ders materyali olarak 12 ders saati kullanılmıştır. Uygulama sonrasında yedi öğrenci ve uygulama öğretmeni ile mevcut araştırma kapsamında geliştirilen görüşme formları aracılığıyla yarı yapılandırılmış görüşmeler gerçekleştirilmiştir. Görüşmelerden elde edilen veriler içerik analizi ile çözümlenerek “Akademik”, “Duyuşsal”, “Günlük Yaşamla İlişkilendirme” ve “Çizgi Roman ve Mizah” temalarında sınıflandırılmıştır. Araştırma sonucunda öğrencilerin ve uygulama öğretmenin çizgi romanın ele alınan konuyu eğlenceli ve anlaşılır kılması, öğrenmeleri kolaylaştırması, kalıcı öğrenmelere fırsat tanıması, bireysel öğrenmelere olanak sunması, derse katılımı artırması, okuma yazma ve dil bilme konusunda problemleri olan öğrencilerin öğrenmelerini desteklemesi gibi durumlardan dolayı etkili bir öğretim materyali olduğu yönünde görüş bildirmişlerdir. Elde edilen sonuçlardan hareketle bağlam temelli olarak tasarlanan çizgi romanın öğrencilerin öğrenmelerini desteklemesinden dolayı öğretim materyali olarak farklı ünite ve derslerde yaygınlaştırılması tavsiye edilmiştir

Dynamic threshold-based algorithms for communication networks

Ankara : The Department of Electrical and Electronics Engineering and the Institute of Engineering and Sciences of Bilkent University, 2009.Thesis (Master's) -- Bilkent University, 2009.Includes bibliographical references leaves 68-72.A need to use dynamic thresholds arises in various communication networking scenarios under varying traffic conditions. In this thesis, we propose novel dynamic threshold-based algorithms for two different networking problems, namely the problem of burst assembly in Optical Burst Switching (OBS) networks and of bandwidth reservation in connection-oriented networks. Regarding the first problem, we present dynamic threshold-based burst assembly algorithms that attempt to minimize the average burst assembly delay due to burstification process while taking the burst rate constraints into consideration. Using synthetic and real traffic traces, we show that the proposed algorithms perform significantly better than the conventional timer-based schemes. In the second problem, we propose a model-free adaptive hysteresis algorithm for dynamic bandwidth reservation in a connection-oriented network subject to update frequency constraints. The simulation results in various traffic scenarios show that the proposed technique considerably outperforms the existing schemes without requiring any prior traffic information.Toksöz, Mehmet AltanM.S