Scopus
Permanent URI for this collectionhttps://acikarsiv.thk.edu.tr/handle/123456789/2550
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Publication New aspects of time fractional optimal control problems within operators with nonsingular kernel(American Institute of Mathematical Sciences (AIMS), 2020) Tuğba Akman Yıldız; Amin Jajarmi; Burak Yıldız; Dumitru BaleanuPublication Lee-Wald charge and asymptotic behaviors of the Weyl-invariant topologically massive gravity(IOP Publishing, 2020-10-14) Suat Dengiz; Ercan Kilicarslan; M Reza SetareAbstract We apply the Lee–Wald covariant phase space method to the Weyl-invariant topologically massive gravity and compute the corresponding on-shell conserved charges. By using appropriate decay conditions for the existing propagating modes in the near-horizon of a stationary black hole, we obtain the charges generating the asymptotic symmetries. We show that the charges are integrable and the (modified) algebras among the asymptotic generators are closed for the certain choice of central extensions.Publication A Sturm-Liouville approach for continuous and discrete Mittag-Leffler kernel fractional operators(American Institute of Mathematical Sciences (AIMS), 2021) Raziye Mert; Thabet Abdeljawad; Allan PetersonPublication THEORETICAL INVESTIGATION OF ROCKET ENGINES FOR OXYGEN AND ETHANE LIQUID BIPROPELLANT(Pushpa Publishing House, 2021-11-10) Nevsan SengilPublication Assessment of vaccination and underreporting on COVID-19 infections in Turkey based on effective reproduction number(World Scientific Pub Co Pte Ltd, 2024-01-12) Tuğba Akman; Emek Köse; Necibe TuncerIn this paper, we introduce a SEIR-type COVID-19 model where the infected class is further divided into subclasses with individuals in intensive care (ICUs) and ventilation units. The model is calibrated with the symptomatic COVID-19 cases, deaths, and the number of patients in ICUs and ventilation units as reported by Republic of Turkey, Ministry of Health for the period 11 March 2020 through 30 May 2020 when the nationwide lockdown is in order. COVID-19 interventions in Turkey are incorporated into the model to detect the future trend of the outbreak accurately. We tested the effect of underreporting and we found that the peaks of the disease differ significantly depending on the rate of underreporting, however, the timing of the peaks remains constant. The lockdown is lifted on 1 June, and the model is modified to include a time-dependent transmission rate which is linked to the effective reproduction number [Formula: see text] through basic reproduction number [Formula: see text]. The modified model captures the changing dynamics and peaks of the outbreak successfully. With the onset of vaccination on 13 January 2021, we augment the model with the vaccination class to investigate the impact of vaccination rate and efficacy. We observe that vaccination rate is a more critical parameter than the vaccine efficacy to eliminate the disease successfully.Publication On Kähler structures of Taub-Nut and kerr spaces(World Scientific Pub Co Pte Ltd, 2022-10-07) Özgür Kelekçi̇; Kelekçi, ÖzgürIn this paper, we study the Kählerian nature of Taub-NUT and Kerr spaces which are gravitational instanton and black hole solutions in general relativity. We show that Euclidean Taub-NUT metric is hyper-Kähler with respect to the usual almost complex structures by employing an alternative explicit coframe, and Euclidean Kerr metric is globally conformally Kähler. We also show that conformally scaled Euclidean Kerr space admits a Kähler structure by applying a conformal scaling factor stemming from the Lee-form of the original metric or alternatively a factor coming from self-dual part of the Weyl tensor [Formula: see text].Publication Classification of Killing magnetic curves in ℍ3(World Scientific Pub Co Pte Ltd, 2023-08-29) Özgür Kelekçi; Furkan Semih Dündar; Gülhan Ayar; Kelekçi, ÖzgürIn this paper, we study classification of magnetic curves corresponding to Killing vector fields of [Formula: see text]. First, we solve the geodesic equation analytically. Then we calculate the trajectories generated by all the six Killing vector fields, which are considered as magnetic field vectors, by using perturbation method up to first-order with respect to the strength of the magnetic field. We present a comparison of our solution with the numerical solution for one case. We also prove that 3-dimensional [Formula: see text]-Kenmotsu manifolds cannot have any magnetic vector field in the direction of their Reeb vector fields.Publication Evaluation of energy storage alternatives for hybrid energy systems using a hesitant fuzzy approach(American Institute of Mathematical Sciences (AIMS), 2024) Ahmet Aktas; Mehmet KabakPublication Problem space search metaheuristics with fix and optimize approach for the integrated fleet sizing and replenishment planning problem(American Institute of Mathematical Sciences (AIMS), 2024) Duygu Aghazadeh; Kadir Ertogral; Aghazadeh, Duygu