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Assessing dyslexia with machine learning: a pilot study utilizing Google ML Kit
(IEEE, 2023-12-19) Eroğlu, Günet; Harb, Mhd Raja Abou
In this study, we explore the application of Google ML Kit, a machine learning development kit, for dyslexia detection in the Turkish language. We collected face-tracking data from two groups: 49 dyslexic children and 22 typically developing children. Using Google ML Kit and other machine learning algorithms based on eye-tracking data, we compared their performance in dyslexia detection. Our findings reveal that Google ML Kit achieved the highest accuracy among the tested methods. This study underscores the potential of machine learning-based dyslexia detection and its practicality in academic and clinical settings.
Optimum torque distribution during regenerative braking in a fully electrical vehicle via dynamic programming
(IEEE, 2023-10-28) Ergün, Ömer; Çaycı, N. Okan; Dinçmen, Erkin; İstif, İlyas
In electric vehicles, it is important to maximize their regenerative braking performances for obtaining longer driving distances. In this study, for an electric vehicle having motors on the front and rear axles, an optimum torque distribution algorithm based on dynamic programming method is proposed for maximizing the regenerative braking energy. Electric motor limits, efficiency maps, battery model and braking force constraints given in the European regulations are considered in the proposed algorithm. The dynamic programming algorithm code and simulation studies for different braking scenarios are carried out via MATLAB. Simulation studies show that via the proposed torque distribution algorithm, significant improvements in the regenerated braking energy are obtained with respect to the fixed-rate torque distribution algorithm.
Investigation of residual stresses induced by milling of compacted graphite iron by x-ray diffraction technique
(Springer, 2024-04) Kara, Mehmet Emre; Kuzu, Ali Taner; Bakkal, Mustafa
This study investigates the relationship between residual stresses, cutting parameters, and machining performance in the milling process of compacted graphite iron (CGI). X-ray diffraction (XRD) analysis is employed to measure residual stresses on the cast and milled surfaces, while cutting force modeling is utilized to calculate the tangential force, power, and active work. The results demonstrate that tensile residual stresses are predominant on the milled surfaces, attributed to the both mechanical and thermal loads generated during milling. By analyzing various cutting conditions, it is observed that lower feeds contribute to reduced plastic deformation, resulting in lower residual stress levels. Additionally, higher cutting speeds lead to higher temperatures, but due to the shorter machining time, heat accumulation is limited, resulting in higher residual stresses, especially at low feeds. At high feeds, residual stresses decreased as the cutting speed increased. The interplay between cutting parameters and residual stresses highlights the need for optimizing cutting conditions to enhance fatigue strength in CGI components. These findings provide valuable insights for process optimization and quality control in the milling of CGI materials.
Neural network steering control algorithm for autonomous ground vehicles having signal time delay
(SAGE Publications Ltd, 2024-03) Dinçmen, Erkin
An adaptive neural network–based steering control algorithm is proposed for yaw rate tracking of autonomous ground vehicles with in-vehicle signal time delay. The control system consists of two neural networks: the observer neural network and the controller neural network. The observer neural network adapts itself to the system dynamics during the training phase. Once trained, the observer neural network cooperates with the controller neural network, which constantly adapts itself during the control task. In this way, an adaptive and intelligent control structure is proposed. Through simulation studies, it has been shown that while a proportional-integral-derivative type steering controller fails to perform its control task in case of steering signal delay, the proposed control algorithm manages to adapt itself according to the control problem and achieves reference yaw rate tracking. The robustness of the control algorithm according to the signal delay magnitude has been demonstrated by simulation studies. A rigorous Lyapunov stability analysis of the control algorithm is also presented.
Tribo-corrosion behavior of electroplating, nitrocarburizing, and QPQ processes on barrel finishing
(Walter de Gruyter GmbH, 2023-11-27) Yücel, Aysu Hande; Yılmaz, Alpay; Bakkal, Mustafa; Kuzu, Ali Taner
In this study, the effects of nitrocarburizing, QPQ, and Cr coating on the surface properties of 32CrMoV12-10 gun barrels are discussed. Hardness measurements, pin-on-disc tests, and anodic polarization tests were performed to examine the hardness values, wear resistance, friction coefficient, and corrosion resistance. The hardness of the specimen treated with QPQ was found to be the highest. Comparing the hardness profiles, it was observed that the casing depth of the nitrocarburized sample was shallower than that of the QPQ-treated sample. The pin-on-disc test revealed that the nitrocarburized sample exhibited a high coefficient of friction, while the Cr-coated sample showed the lowest coefficient of friction. Analyzing the Tafel polarization curve, it was determined that the nitrocarburized and QPQ-treated specimens demonstrated similar levels of corrosion resistance. However, it can be noted that the QPQ-treated specimen had a slightly lower corrosion rate.
The development of a hybrid cutting model for workpiece temperature distribution via advection heat partition approach
(Springer Science and Business Media Deutschland GmbH, 2023-04-15) Kara, Mehmet Emre; Kuzu, Ali Taner; Bakkal, Mustafa
This paper presents a novel hybrid cutting model for the prediction of workpiece temperature distribution during the dry milling process of compacted graphite iron (CGI). The hybrid model consists of an analytical force model based on a mechanistic approach and finite element analysis (FEA) based on the thermal model. The heat generated during the milling process transferred to the workpiece is computed via the advection heat partition model. The workpiece temperature distribution obtained through the heat loads, using as boundary conditions in the FEA, was calculated by means of cutting forces. The developed force and thermal models have been experimentally validated, and good agreement between the measured and calculated results has been observed. The energy and active work calculations show that by doubling the feed during CGI milling, an energy saving of about 10% is achieved despite almost doubling the cutting forces.
Development of acoustic and thermal insulation materials from pantyhose waste
(Trans Tech Publications Ltd, 2023-03-31) Küçükali Öztürk, Merve; Sezgin, Hande; Yalçın Enis, İpek; Dolu, Cem
Population growth, urbanization, industrialization, developing technology, increasing welfare level and changing consumption habits cause solid wastes to increase day by day. There are also sub-waste groups that have not yet been fully recognized among the solid waste groups in which textile wastes have a large share. One of them is pantyhose, which has been indispensable for modern life since the day it was presented to the consumer. These socks, which are made of polyamide and elastane fibers that are easily punctured, run and become unusable when worn once or several times, are generally thrown away after use. These pantyhose wastes, which are not biodegradable due to their raw materials, also pose an environmental risk. Within the scope of the study, thermal and sound insulation properties of carded and needle-punched pantyhose wastes are investigated. The results show that the thermal and acoustic properties of the developed material are at a sufficient level, and it has ensured that polyamide wastes, which have superior properties among thermoplastic polymers and have high economic value, are brought back into the economy.
A source seeking algorithm with application to a quadcopter model
(Nova Science Publishers, 2019-01-01) Dinçmen, Erkin
A novel extremum seeking (ES) algorithm is developed and its performance is tested on a quadcopter type unmanned aerial vehicle (UAV) model. The motivation of the paper is to develop an ES algorithm that results no oscillations in the system behaviour during the search process. Via the proposed algorithm, the quadcopter searches autonomously a signal source/target without knowing its location a priory. The controller does not use any position or GPS measurements. The presented control algorithm is composed of two phases: In the first phase, the search algorithm determines required translational acceleration values of the UAV. In the second phase, a PID-type controller is utilized to control roll and pitch angles of the UAV to maintain computed acceleration values via the search algorithm. Performance of the controller is evaluated via simulation studies.
Eastern Anatolia Observatory (DAG): recent development in 2019
(Universidad Nacional Autonoma de Mexico, 2019-10-04) Yeşilyaprak, Cahit; Keskin, Onur
Eastern Anatolia Observatory (DAG) will be the Turkey’s largest (4m) and first infrared observatory is located in Erzurum city at the East part of Turkey with an altitude of 3170 m. We present the recent development of DAG until the end of September in 2019.
Wind disturbance cancellation for smaller alt-azimuth telescopes
(Universidad Nacional Autonoma de Mexico, 2019-10) Ünal, Ali Cem; Kararsız, Gökhan; Yılmaz, Cem Tuğrul; Keskin, Onur; Yeşilyaprak, Cahit
This study focuses on eliminating unknown amplitude wind disturbance for 2-DOF alt-azimuth configuration small telescopes. An adaptive controller is designed to overcome wind disturbance as a set and forget system. The mathematical model is derived based on 2-DOF alt-azimuth configuration. The wind disturbance is modeled as a sum of sinusoidal with unknown amplitude, frequency and phase by using Wind-Gust model. The controller aims to cancel the effect of the disturbance on the altitude and azimuth angles of the telescope while positioning or staying static on a dedicated configuration. The asymptotic stability is proven with the Lyapunov approach. The numerical study is illustrated to success of the proposed controller.
TROIA Adaptive optics system for DAG telescope; assembly and laboratory performance prior to on-sky assessment
(SPIE, 2022-08-29) Keskin, Onur; Jolissaint, Laurent; Bouxin, Audrey; Yeşilyaprak, Cahit
In this article, we describe the current status of the development of TROIA* a pyramid wavefront sensor based adaptive optics system designed for DAG, a new 4 m telescope located in Eastern Anatolia, Turkey. The wavefront uses a no-noise electron-multiplied CCD camera, and the deformable mirror has a large actuators density, allowing coronagraphic science in one hand, but also system optimization for low light level or bad seeing conditions thanks to the versatility of the P-WFS. We describe the optical design, the mounting and alignment procedure and our loop control concept. Closed loop results are described, showing that while there are still many issues to fix before the sky version, the system behaves as expected.
Jet motorlarinda uygulanan efüzyon film soğutma akış karakteristiklerinin PIV yöntemiyle incelenmesi
(Sürdürülebilir Havacılık Araştırma Derneği, 2018-12-01) Yalçın, Sinan Eren; Yakın, Evren Yılmaz; Kuşhan, Melih Cemal; Karakoç, Tahir Hikmet
Efüzyon soğutma tekniği, modern yanma odalarında kullanılan en gelişmiş soğutma teknolojisidir. Bu çalışmada 1/9 ölçekte boyutlandırılmış bir yanma odası cidarında, efüzyon film soğutmanın ana akım üzerine etkileri Parçacık Görüntülemeli Hız Ölçümü (PIV) yöntemi kullanılarak deneysel olarak incelenmiştir. Bu amaçla bu çalışmada, ana akım Reynols (Re) sayısı 15000 değerine sabitlenmiş, 2.25 mm delik çaplı efüzyon plakası için, delik açıları 30° ve 45° değişiyor iken, efüzyon plakasından 7 farklı üfleme debisi için testler gerçekleştirilmiş ve soğutma filmi oluşumu incelenmiştir. PIV deneylerinden elde edilen veriler incelenerek, çapraz akışta jet karışımlarında meydana gelen akış haritası çıkarılmıştır ve film oluşma karakteristiği belirlenmiştir. Akış haritası sonuçlarına göre, soğutucu deliklerden düşük debili üflemelerde jetler ana akıma yenik düşmekte, tam tersine yüksek debilerde jetler ana akımla eş baskın özellikte olduğu için, film oluşumu gözlemlenmiştir. Ayrıca soğutma deliklerinin açılarının artışının film oluşumuna olumsuz etkisi gösterilmiştir.
Design of the near infrared camera DIRAC for East Anatolia Observatory
(SPIE, 2022) Zhelem, Ross; Content, Robert; Churilov, Vladimir; Kripak, Yevgen; Waller, Lew; Case, Scott; Mali, Slavko; Muller, Rolf; Gonzalez, Mario; Adams, Dave; Binos, Nick; Chin, Timothy; Farrell, Tony; Klauser, Urs; Kondrat, Yuriy; Kunwar, Nirmala; Lawrence, Jon; Lorente, Nuria; Luo, Summer; McDonald, Erica; McGregor, Helen; Nichani, Vijay; Pai, Naveen; Vuong, Minh; Zahoor, Jahanzeb; Zheng, Jessica; Norris, Barnaby; Bryant, Julia; Vaccarella, Annino; Herrald, Nick; Gilbert, James; Yeşilyaprak, Cahit; Güçsav, Bülent; Coker, Deniz; Keskin, Onur; Jolissaint, Laurent
The 4m DAG telescope is under construction at East Anatolia Observatory in Turkey. DIRAC, the " DAG InfraRed Adaptive optics Camera", is one of the facility instruments. This paper describes the design of the camera to meet the performance specifications. Adaptive and auxiliary optics relay the telescope F/14 input 1:1 into DIRAC. The camera has an all refractive design for the wavelength range 0.9 - 2.4 micron. Lenses reimage the telescope focal plane 33 x 33 as (9 x 9 mm) on a 1k x 1k focal plane array. With magnification of 2x, the plate scale on the detector is 33 mas/pixel. There are 4 standard filters (Y, J, H, K) and 4 narrowband continuum filters. A 12 position filter wheel allows installation of 2 extra customer filters for specific needs; the filter wheel also deploys a pupil viewer lens. Optical tolerancing is carried out to deliver the required image quality at polychromatic Strehl ratio of 90% with focus compensator. This reveals some challenges in the precision assembly of optics for cryogenic environments. We require cells capable of maintaining precision alignment and keeping lenses stress free. The goal is achieved by a combination of flexures with special bonding epoxy matching closely the CTE of the lens cells and crystalline materials. The camera design is very compact with object to image distance <220 mm and lens diameters <25 mm. A standalone cryostat is LN2 cooled for vibration free operation with the bench mounted adaptive optics module (TROIA) and coronagraph (PLACID) at the Nasmyth focus of the DAG telescope.
Eastern Anatolia Observatory (DAG): the status in 2022, towards the first light
(SPIE, 2022) Yeşilyaprak, Cahit; Keskin, Onur; Jolissaint, Laurent
East Anatolian Observatory's DAG telescope, with its 4m diameter primary mirror and VIS/IR observation capability, Eastern Anatolian Observatory's 4m diameter class DAG telescope, with VIS/IR observation capability, will be located on the Konakll-Karaya summit at an altitude of 3170 m, near the city of Erzurum, Turkey. DAG contains both active optics (aO) and adaptive optics (AO) systems. With the enclosure assembly nearly done, and the dummy mirror integration including the M1 cell integration performed at the end of 2021; DAG telescope's AIV is planned to take place by the end of May/2022 and the Provisional Acceptance by November/2022. DAG is equipped with an in-flange derotator-KORAY (K-mirror Optical RelAY) that will direct the light to the seeing limited Nasmyth platform containing TROIA (TuRkish adaptive Optics system for Infrared Astronomy). The scientific instruments that DAG will receive in 2022, are but not limited to, a stellar coronagraph and a 30"NIR diffraction limited camera. In his paper, a global status update and expected optical performance characteristics will be presented.
DAG 4m telescope: optics completion, on-site integration and test
(SPIE, 2022) Pirnay, Olivier; Albart, Pierre; Bastin, Christian; De Ville, Jonathan; Gabriel, Eric; Leseur, Thibault; Lousberg, Grégory P.; Méant, Laurence; Orban, Sabrina; Tortolani, Jean-Marc; Amalfi, Manfredi; Marchiori, Gianpietro; Rampini, Francesco; Busatta, Andrea; Yeşilyaprak, Cahit; Keskin, Onur
AMOS with EIE as main subcontractor has recently completed the erection of the 4 m telescope located at the Turkish Eastern Anatolia Observatory (DAG) set up by the Ataturk University Astrophysics Research and Application Centre (ATASAM) of Erzurum. The telescope design is based on a Ritchey-Chrétien configuration with two folded Nasmyth focal planes and a focal length of 56m. The optical train is composed of three mirrors: the primary mirror (M1) with an optical aperture of 4m, a convex secondary mirror (M2), and a large flat folding mirror (M3). Diffraction-limited performances in optical and near infrared spectral bands will be achieved thanks to the combination of active and adaptive optics systems. The active optics system is controlling the shape of the primary mirror by means of 66 axial force actuators and position actively the secondary and tertiary mirrors by means of hexapods. The adaptive optics system will be implemented at one of the two Nasmyth ports. As main contractor, AMOS is in charge of the overall project management, the system engineering, the optical design and the active optics development. As main sub-contractor and partner of AMOS, EIE is in charge of the development of the mount. Following the factory acceptance in Europe, the telescope was dismounted and delivered in early 2021. The activities onsite were carried out according to the assembly, integration and verification plan (AIV plan). In the meantime, the fabrication of the 4 m primary mirror was completed, and the full set of mirrors was forwarded on-site before the end of the year 2021. In this paper is presented a brief description of the design and performances of the telescope followed by the project progress status at the time the optics are being integrated in the telescope for the first time. This includes the review of the mirrors as-built quality and the excepted performances of the telescope mount after alignment and tuning. The path forward final acceptance is explained with the presentation of the optical alignment method and the test carried-out on-sky.
DAG-TGI: türbülans jeneratörü kalibrasyonu
(Türk Astronomi Derneği, 2020-12-11) Tezcan, Cihan Tuğrul; Akbulak, Ümit Bora; Güvenir, Furkan; Aydemir, Ömer Faruk; Keskin, Onur; Yeşilyaprak, Cahit
DAG (Doğu Anadolu Gözlemevi) 4-metre birincil ayna ile aktif (aO) ve adaptif (AO) optik sistemlerine sahiptir. DAG’ın odak düzlemi aletlerinin geliştirilmesi ve kurulması için, türbülans şartlarını canlandırabilen bir türbülans jeneratörü geliştirilmiştir. Bu çalışmada jeneratör kalibrasyonu ve karakterizasyonu sağlanmıştır. Türbülans jeneratörü temel olarak soğuk hava ile kontrol edilebilen sıcak havanın gene kontrol edilebilen rüzgar şartlarında karıştırılarak türbülans oluşturmasıdır. Bu çalışma ileride DAG’ın adaptif optik sisteminin simülastonu olacaktır.
Observing with DAG: performance metrics of imaging and spectroscopy
(Türk Astronomi Derneği, 2020-12-11) Jolissaint, Laurent; Zago, Lorenzo; Keskin, Onur
DAG telescope will be designed as a telescope with adaptive optics and seeing limited modes of observation. Its primary mirror will be a thin meniscus, controlled in shape by an active optics system. This implies specific requirements for the mirrors manufacturing errors tolerancing, studied and defined in this document.
DAG-SLODAR (SLOpe Detection And Ranging) Teleskobu
(Türk Astronomi Derneği, 2020-12-11) Şatır, Onur; Yeşilyaprak, Cahit; Keskin, Onur
Atmosferin astronomik gözlemlere olan olumsuz etkilerini alt etmek üzere geliştirilmiş ve DAG teleskobunda da kullanılacak olan Adaptif Optik (AO) sistemleri, türbülansın ayrıntılı bir şekilde karakterize edilmesine ihtiyaç duyar. SLODAR, atmosferik optik türbülansın dikey profilini, iki yakın yıldızın Shack-Hartmann dalgacephesi algılayıcısı (SH-WFC) ile yapılan dalgacephesi eğimi ölçümlerinin çapraz korelasyonundan elde eden bir yöntemdir. SLODAR sistemi, küçük çaplı (?50cm) bir teleskobun odak düzlemine yerleştirilen, iki SH-WFC barındıran SLODAR aygıtından oluşur. Paranal, La Palma, Mauna Kea ve SAAO gözlemevlerinde kurulan SLODAR teleskopları "yer katmanı (ground layer)" olarak adlandırılan ve yerleşkenin üzerindeki ilk kilometre içindeki türbülansı ölçmek amacıyla kullanılmışlardır. Bu sunumda DAG yerleşkesinde kurulmakta olan SLODAR sisteminden bahsedilecektir.
The DAG project and its management
(Türk Astronomi Derneği, 2020-12-11) Zago, Lorenzo; Keskin, Onur
The DAG Project and managerial issues related to call for tenders, determination of technical specifications both for the telescope, the dome and the observatory building will be presented.
DAG türbülans jeneratörü
(Türk Astronomi Derneği, 2020-12-11) Özbaldan, Emrah Emin; Kılıçerkan Başlar, Gamze; Başlar, İsmail; Keskin, Onur; Yeşilyaprak, Cahit
Doğu Anadolu Gözlemevi (DAG) projesi kapsamında; teleskop için gereken ve zorunlu olan Adaptif Optik (AO) sisteminin kontrol sistemlerinin geliştirilmesi, performansı ve ön testlerinin gerçekleştirileceği, atmosferik olarak yapay koşulların oluşturulup deneneceği, gerekli olan Optik Test Laboratuvarı oluşturulmasının ilk ve temel adımı, DAG Türbülans Jeneratörü ile sağlanacaktır. Optik laboratuvar için olmazsa olmaz olan ekipman tarafımızca üretilecektir. Proje kapsamında tarafımızca üretilecek bu jeneratörün temel malzemeleri noktasal kaynaklı lazer, CCD kamera, optik komponentler ve bazı elektronik kartlardır. Bu laboratuvar ve kurulacak sistem sayesinde; öncelikle DAG projesi kapsamındaki AO sisteminin ilk testlerinin yapılması planlanmaktadır.

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