Bildiri Koleksiyonu | Makine Mühendisliği Bölümü

Bu koleksiyon için kalıcı URI

https://hdl.handle.net/11729/5107

Listeleniyor 1 - 20 / 57

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.
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, Cemal 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.
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.
DAG odak düzlemi araçları - hedefler ve seçenekler
(Türk Astronomi Derneği, 2020-12-11) Yerli, Sinan Kaan; Yeşilyaprak, Cahit; Keskin, Onur; Güver, Tolga
DAG projesi çerçevesinde, teleskobun da tanımlanması ve optiğinin belirlenmesinden sonra Türk Astronomisinin gereksinim ve gelecek hedefleri de gözetilerek proje ekibi DAG teleskobunun iki Nasmyth odağına yerleştirilecek olası tayfölçer ve görüntüleme araçları için öngörülerde bulunmuş ve yeni bir proje teklifi vermiştir. Bu bildiride bu süreç tanıtılıp sunulan yeni proje tanıtılacaktır.
Adaptive optics for DAG telescope
(Türk Astronomi Derneği, 2020-12-11) Keskin, Onur; Jolissaint, Laurent
What we propose for DAG is therefore a natural guide star GLAO system, that can be turned into a highly efficient AO system. Thus the working principle and expected performance analysis will be shown. In this manner most DAG users will be able to make some use of the DAG AO. Later, it will be possible to upgrade the system by changing th algorithm and adding 1 or 2 additional DM, and even laser guide stars.
The effects of atmospheric turbulence on astrophysical observations
(Türk Astronomi Derneği, 2020-12-11) Keskin, Onur
Atmospheric turbulence is caused by random variations in temperature and pressure that spatially and temporally alter the air’s index of refraction. As electro-magnetic radiation from distant astronomical objects propagates through the atmosphere, the waves of light are distorted by these fluctuations in the refractive index and the information stored in the wavefront is corrupted. For astronomers, this loss of information manifests as degradation in the angular resolution that can be achieved with a ground-based telescope.
OPAM tarafından üretilen derotator sistemi ve TROIA (Turkish Adaptive Optics System for Infrared Astronomy) adaptif optik sistemi
(Türk Astronomi Derneği, 2020-12-11) Keskin, Onur
DAG teleskopu için FMV Işık Üniversitesi Optomekatronik Uygulama ve Araştırma Merkezi’nde (OPAM) son tasarımı başarıyla bitirilerek, üretim aşamasına geçilen derotator ve adaptif optik (TROIA) sistemleri tanıtılacaktır.
İstabul Üniversitesi gözlemevi odak düzlemi aygıtı test ve karakterizasyon laboratuvarı
(Türk Astronomi Derneği, 2020-12-11) Aliş, Sinan; Güver, Tolga; Erol, Ayşe; Ege, Ergün; Kay, Burak; Yelkenci, Korhan; Yeşilyaprak, Cahit; Keskin, Onur; Yerli, Sinan Kaan; Sercan, Fahreettin; Fişek, Süleyman
Doğu Anadolu Gözlemevi Odak Düzlemi Aygıtları ve Adaptif Optik Sistemi başlıklı, 2016K121370 numaralı T.C. Kalkınma Bakanlığı projesi ve İstanbul Üniversitesi Rektörlüğü desteğinde yürüyen çalışmalar kapsamında İstanbul Üniversitesi Astronomi ve Uzay Bilimleri Bölümü’nde teleskop odak düzlemi aygıtı test ve karakterizasyon laboratuvarı kurulum çalışmaları başlatılmıştır. Başta DAG Teleskobu olmak üzere ülkemizdeki tüm gözlemevlerine hizmet verebilecek şekilde tasarlanan laboratuvar, CCD kamera, filtre ve odak düzlemi aygıtları için bir test masasına sahip olacaktır. Bu sunumda, laboratuvarın kurulumu ve alımlarında gelinen son noktanın yanı sıra, İstanbul Üniversitesi Fizik Bölümü Nano-Optoelektronik Araştırma Laboratuvarları ile birlikte yapılması planlanan çalışmalar sunulacaktır.
Optical design of the adaptive optics system for DAG, the new 4 m Turkish telescope
(SPIE, 2020) Bouxin, Audrey; Jolissaint, Laurent; Keskin, Onur; Yeşilyaprak, Cahit; Spanò, Paolo
We present the design of the Adaptive Optics System for the new Turkish 4-m telescope (DAG). The AO will use a pyramid WFS, with a double prism and a no noise EM-CCD camera to allow for oversampling of the pupil images and a relaxation of the prism manufacturing tolerances. In order to use the high modal resolution of the P-WFS allowed by the adjustment of the modulation angle, we implement a high order deformable mirror with 468 actuators, which will permit to use the system in extreme AO correction mode. The P-WFS optical design has been largely inspired by NFIRAOS truth WFS. The number of optical surfaces has been reduced to the bare minimum. An atmospheric dispersion compensator is introduced around the tip-tilt modulation mirror. In this proceeding, we present the detail of the optical design steps for all the components of the system.
TROIA adaptive optics system for DAG Telescope
(SPIE, 2020-12-13) Keskin, Onur; Jolissaint, Laurent; Bouxin, Audrey; Yeşilyaprak, Cahit
This paper presents the specifications of TROIA-TuRkish adaptive Optics system for Infrared Astronomy system, the science rationale for these specifications, and description of the site technical and environmental conditions to be taken into account in the adaptive optics (AO) system design for the Eastern Anatolia Observatory-DAG telescope. With it's 468 actuators, EMCCD camera, and the pyramid wavefront sensor configuration; TROIA is able to adapt the degree of correction to a given guide star (GS) brightness during observations. The high actuator density of TROIA AO system will allow DAG to perform astronomical observations at ExAO performances.

Güncel Gönderiler