Ortak Dersler Bölümü

Permanent URI for this communityhttps://hdl.handle.net/20.500.12416/1817

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21. yy becerilerinin kazandırılmasında yaratıcı yazmanın önemi.
(Pegem Akademi, 2018) Akkoyunlu, Buket; 8539
A New Estimation Technique for AR(1) Model with Long-Tailed Symmetric Innovations
(2017) Dener Akkaya, Ayşen; Türker Bayrak, Özlem; 56416
In recent years, it is seen in many time series applications that innovations are non-normal. In this situation, it is known that the least squares (LS) estimators are neither efficient nor robust and maximum likelihood (ML) estimators can only be obtained numerically which might be problematic. The estimation problem is considered newly through different distributions by the use of modified maximum likelihood (MML) estimation technique which assumes the shape parameter to be known. This becomes a drawback in machine data processing where the underlying distribution cannot be determined but assumed to be a member of a broad class of distributions. Therefore, in this study, the shape parameter is assumed to be unknown and the MML technique is combined with Huber’s estimation procedure to estimate the model parameters of autoregressive (AR) models of order 1, named as adaptive modified maximum likelihood (AMML) estimation. After the derivation of the AMML estimators, their efficiency and robustness properties are discussed through simulation study and compared with both MML and LS estimators. Besides, two test statistics for significance of the model are suggested. Both criterion and efficiency robustness properties of the test statistics are discussed, and comparisons with the corresponding MML and LS test statistics are given. Finally, the estimation procedure is generalized to AR(q) models.
A New Estimation Technique for AR(1) Model with Long-Tailed Symmetric Innovations
(Springer, 2018) Dener Akkaya, Ayşen; Türker Bayrak, Özlem; 56416
In recent years, it is seen in many time series applications that innovations are non-normal. In this situation, it is known that the least squares (LS) estimators are neither efficient nor robust and maximum likelihood (ML) estimators can only be obtained numerically which might be problematic. The estimation problem is considered newly through different distributions by the use of modified maximum likelihood (MML) estimation technique which assumes the shape parameter to be known. This becomes a drawback in machine data processing where the underlying distribution cannot be determined but assumed to be a member of a broad class of distributions. Therefore, in this study, the shape parameter is assumed to be unknown and the MML technique is combined with Huber’s estimation procedure to estimate the model parameters of autoregressive (AR) models of order 1, named as adaptive modified maximum likelihood (AMML) estimation. After the derivation of the AMML estimators, their efficiency and robustness properties are discussed through simulation study and compared with both MML and LS estimators. Besides, two test statistics for significance of the model are suggested. Both criterion and efficiency robustness properties of the test statistics are discussed, and comparisons with the corresponding MML and LS test statistics are given. Finally, the estimation procedure is generalized to AR(q) models.
A phenomenological study on ferroelastic KH3(SeO3)(2) and KD3(SeO3)(2)
(2021) Kiracı, Ali; 42475
The anomalous behavior of the Brillouin frequency shift omega of the soft acoustic mode for KH3(SeO3)(2) and KD3(SeO3)(2), and also the volume thermal expansion proportional to(V) and the specific heat C of KH3(SeO3)(2) have been analyzed for various temperature intervals close to the phase transition temperatures TC at around 211 K and 302 K, respectively. Our extracted values of the critical exponent from C and proportional to(V) of KH3(SeO3)(2) within the temperature intervals of vertical bar T -T-C vertical bar < 7 K are nearly zero, while the critical exponent extracted from the Brillouin frequency shift data of both KH3(SeO3)(2) and KD3(SeO3)(2) within the same temperature interval of vertical bar T -T-C vertical bar < 7 K decrease very rapidly toward to zero as the phase transition temperatures are approached. Our results indicate that the critical behavior of omega, proportional to(V) and C of both KH3(SeO3)(2) and KD3(SeO3)(2) can be described with the same critical exponent within the temperature interval of vertical bar T -T-C vertical bar < 2 K.
A phenomenological study on ferroelectric pyridinium tetrafluoroborate (C5NH6) BF4
(Elsevier, 2019) Kiracı, Ali; 42475
The temperature dependence of the specific heat C-V of (C5NH6)BF4 was analyzed according to a power law formula with a critical exponent alpha deduced from the compressible Ising model in the vicinity of the phase transition temperatures of T-C1 = 238 K and T-C2 = 204 K. The extracted values of the critical exponent alpha within the temperature intervals of vertical bar T - T-C1 vertical bar < 6 K and also T - T-C2 < 6 K were consistent with that predicted from the 3d-Ising model (alpha = 0.10) while obtained values of alpha within the temperature interval of T-C2 - T < 6 K were consistent with that predicted from 2-d potts model (alpha = 0.30). In addition, the thermodynamic quantities: the internal energy (U), the entropy (S) and the Helmholtz free energy (F) of this compound were calculated on the basis of the extracted values of the critical exponent a below and above the phase transition temperatures of T-C1 and T-C2.
A phenomenological study on ferroelectric β-glycine
(2021) Kiracı, A; 42475
The anomalous behavior of the specific heat for (Formula presented.) -glycine was analyzed in terms of the compressible Ising model approximately 5 K below and above the ferrelectric-paraelectric phase transition temperature of TC = 252 K. The obtained value of the critical exponent (Formula presented.) = 0.12 in the ferroelectric phase (T < TC) was consistent with that predicted from the 3-d Ising model ((Formula presented.) = 0.13), while the obtained value of (Formula presented.) = 0.32 in the paraelectric phase (T > TC) was consistent with that predicted from the 2-d potts model ((Formula presented.) = 0.30). Some thermodynamic quantities such as the internal energy, the entropy and the free energy of (Formula presented.) -glycine were then predicted in terms of these extracted values of the critical exponents close to the phase transition temperature of TC. Our calculated values of the thermodynamic quantities are in good agreement with the observed data.
A sign of the past: Aliye berger
(2015) Okur Tolun, Elif
Aliye Berger , who has a privileged place in The Turkish Painting Art , stayed away from the generation clash of her time and various groupings. She was an artist who had an aim to acquire a place in art community. Her privileged place in art , and her life without giving attention to social pressure has result as reflecting her own her life style to her works. She is one of the artists who acts as herself. Her artistic style is just like an action which has a fictional expression upon her own identity. Creation is not producing extraordinary things, creating shapes and strolling around the current time. Art has no gender, nationality and race. What is important is the necessity to do something real by feeling those deeply. People whom we can call genuine artists can easily assimilate polyphony in life and with some sensibility they can spend a whole life to reflect these with some bravery. Just as Aliye Berger, her art is also fed by her life. Her actions become a part of her life and create their own symbols. Thus, her works turn into their genuine feature. In this paper, it is aimed to understand the identity of Aliye Berger through her gravures. As a woman artist who has gone beyond her own age with an analysis through her art, it is aimed to investigate her artistic personality and extraordinary sensitivity. This study is neither a history of art nor a biography of literary agent; it is an approach with the artist’s eye Berger’s drawings. Trying to understand her through the fancy world she created, insight of beauty, a place of fiction, technical restructuring and critiques related to her art and the visual materials and by investigating her works we wanted to create a written portrait of Aliye Berger. Keywords: Aliye Berger, print making, identity, gravure, image.
A Study On How to Equip Students With Scientific Communication Skills
(Springer Verlag, 2018) Akkoyunlu, Buket; Akkoyunlu, Buket; 8539
The purpose of this study was to investigate the effects of scientific communication (SC) curriculum on blog writing skills of sixth-grade students, and opinions of the students and teachers about the curriculum. Through the curriculum, it was aimed to teach students the ability to access and evaluate information, organize information and share it by writing a blog. Students were given three different writing assignments and were asked to share them in their blogs. The first assignment was given for adapting to the writing process. The second and third assignments were assessed to determine the effect of SC curriculum on blog writing skills. At the end of the process, teachers and students were asked about their opinions on SC curriculum and blog writing. Study results revealed that SC curriculum had positive effects on research and writing skills development of the students, and showed that the curriculum was supportive in reaching the course-specific goals.
A Theoretical Investigation: Effect of Structural Modifications on Molecular, Electronic, and Optical Properties of Phosphonate Substituted BODIPY Dyes
(2021) Tasgin, Dilek Isik; Sirin, Pınar Seyitdanlioglu; 169107
Phosphonates are important organophosphorus compounds which exhibit versatile properties in organic chemistry, medicinal chemistry, materials and biological applications. Phosphonate groups have appeared in a very few examples of BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) compounds that are important florescent dyes in these areas. The deficiency in the area motivated us to investigate how the phosphonate substituent(s) affect the structural, electronic, and optical properties of meso, α, or α, α′-substituted BODIPYs using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) methods. We have identified the suitable method as HSEH1PBE functional in combination with the basis set 6-31+G** by comparing the theoretical results with the experimental studies. Structural, electronic and optical parameters of a series of designed phosphonate substituted 12 BODIPYs (1-4) have been investigated. The α, and α, α′-vinyl phosphonate substituted BODIPYs (3,4) compared to meso-substituted BODIPYs (1,2) have both lower HOMO/LUMO electronic energies [(−5.57)-(−6.19)/(−3.16)-(−3.91)] and lower electronic energy gaps (Egap) (2.11–2.42). Electrostatic potential analysis was performed for all BODIPYs to characterize their electron distribution and TD-DFT analysis was used for the absorption spectral analysis. The presented theoretical approach can be a practical guide for experimental studies for the design of new BODIPY compounds with desired properties.
Analysis and mathematical computation of some dynamic function for strontium stannate
(2021) Aşkun, Ali Rıza; 56475
The frequency and full width at half maximum (FWHM) data of the Ag Raman modes (95.4, 231.4 and 263.2 cm−1) in strontium stannate crystal have been analyzed using the Balkanski model and the fitting parameters were determined. Also, the isobaric Grüneisen parameter of Ag Raman modes studied here was computed below the room temperature. This computation was performed from the unit cell volume and the observed frequency data of this crystal. Finally, values of the activation energy were extracted close to the structural phase transition temperatures of 160 and 265 K using the observed FWHM data of strontium stannate.
Analysis and mathematical computation of some dynamic functions for the guanidine zinc sulfate
(2021) Aşkun, A.R.; Kiraci, A.; 56475
A power-law formula with a critical exponent (Formula presented.) was used to analyze the anomalous behavior of the specific heat for guanidine zinc sulfate (GZS) crystal close to the phase transition temperature of TC = 178.4 K. The obtained values of 0.13 and 0.14 for (Formula presented.) below (T < TC) and above (T > TC) the phase transition temperature, respectively, were almost the same value of 0.13 (1/8) that predicted from the 3-D Ising model. Also, the internal energy (Formula presented.) the entropy (Formula presented.) and the free energy (Formula presented.) of this crystal were calculated as a function of temperature close to the phase transition temperature of TC = 178.4 K.
Analysis of the specific heat and the free energy of [N(CH3)(4)](2)ZnBr4 close to the ferro-paraelastic phase transition
(2019) Kiracı, Ali; 42475
A power-law formula deduced from the Ising model was used to analyze the temperature dependence of the specific heat and the Gibbs free energy of [N(CH3)(4)](2)ZnBr4 compound in the vicinity of the phase transition temperature of T-C = 287.2 K. Obtained values of the critical exponents from the Gibbs free energy were consistent with that predicted from 2-d potts model ( = 0.3), while obtained values of from the specific heat in both ferroelastic and paraelastic phases were consistent with that predicted from the mean field theory ( = 0) in the vicinity of the phase transition temperature. This is an indication of that [N(CH3)(4)](2)ZnBr4 compound undergoes a second order type phase transition. Also, the enthalpy () and the entropy () of this crystal were calculated in terms of the extracted values of the critical exponent in both ferroelastic and paraelastic phases.
Analysis of the specific heat and the free energy of [N(CH3)(4)](2)ZnBr4 close to the ferro-paraelastic phase transition
(Taylor&Francis LTD, 2019) Kiracı, Ali; 42475
A power-law formula deduced from the Ising model was used to analyze the temperature dependence of the specific heat and the Gibbs free energy of [N(CH3)(4)](2)ZnBr4 compound in the vicinity of the phase transition temperature of T-C = 287.2 K. Obtained values of the critical exponents from the Gibbs free energy were consistent with that predicted from 2-d potts model ( = 0.3), while obtained values of from the specific heat in both ferroelastic and paraelastic phases were consistent with that predicted from the mean field theory ( = 0) in the vicinity of the phase transition temperature. This is an indication of that [N(CH3)(4)](2)ZnBr4 compound undergoes a second order type phase transition. Also, the enthalpy () and the entropy () of this crystal were calculated in terms of the extracted values of the critical exponent in both ferroelastic and paraelastic phases.
Bilim Haritalama Yöntemi ve Eğitim Teknolojisi Alanında Yürütülen Eğilim Araştırmalarına Katkıları
(Pegem, 2019) Akkoyunlu, Buket; Yılmaz Soylu, Meryem; Deryakulu, Deniz; Akkoyunlu, Buket; 8539
Bilimsel iletişim becerilerini değerlendirmeye yönelik bir rubrik geliştirme çalışması
(2018) Akkoyunlu, Buket; Akkoyunlu, Buket; 8539
Bilişötesi Düşünme
(2020) Akkoyunlu, Buket; Akkoyunlu, Buket; 8539
İnsanların günlük yaşamlarında bellek kullanımı, bilimsel düşünme, sosyal etkileşim gibi süreçlerin temelinde bireyin kendi ve diğerlerinin düşüncelerinin farkında olmayı gerektiren bilişötesi süreçler yer almaktadır. Bu bölüm; bilişötesi düşünme süreçlerinin gelişimi, farklı yaklaşımlar ve kuramlar açısından bilişötesinin tanımları ve boyutlarının açıklanması ile başlamaktadır. Alanyazında yapılan birçok araştırma bilişötesi bilgi ile bilişötesi becerinin harmanlanarak kullanıldığı ortamların başarılı öğrenme çıktılarını öngördüğünü göstermektedir. Bu doğrultuda bu bölümün ilerleyen kısımlarında bilişötesinin öğrenme süreçleri ile ilişkisi ele alınmaktadır. Bilişötesinin öğrenenlere kazandırılmasına rehberlik eden ilkeler ve bu ilkeler ile bilişötesinin doğası çerçevesinde teknolojinin bilişötesi öğretiminde oynayacağı rol de bu bölüm çerçevesinde tartışılmaktadır.
Calculation of the infrared frequencies as a function oftemperature using the volume data in the ferroelectric phase ofnano2
(Taylor&Francis INC, 2014) Kiracı, Ali; Kiracı, Ali; 42475
We calculate the temperature dependence of the infrared frequencies of the TO and LO modes with the symmetries of A(1), B-1 and B-2 mainly in the ferroelectric phase of NaNO2. This calculation is carried out using the volume dependence of the infrared frequencies through the mode Gruneisen parameter in this crystal. The volume dependences of the infrared frequencies are fitted to the observed frequencies by using constant mode Gruneisen parameter in the ferroelectric phase of NaNO2. Our results show that this method of calculating the infrared frequencies describes the observed behaviour of NaNO2 adequately.
Calculation of the raman frequency, damping constant (Linewidth) and the relaxation time near the tetragonal-cubic transition in PbTiO3
(Elsevier GMBH, 2017) Kiracı, Ali; Yuetseven, Hamit; 42475
Frequencies, damping constants and the relaxation times of some Raman modes including the two soft modes are calculated as a function of pressure near the tetragonal-cubic transition in PbTiO3. Calculation of the Raman frequencies is performed using the observed volume data from the literature by means of the mode Gruneisen parameter at various pressures. Pressure dependence of the damping constant and the relaxation time is predicted using the pseudospin-phonon coupled model and the energy fluctuation model by considering that the Raman frequency can be taken as the order parameter (spontaneous polarization) for the tetragonal-cubic transition in PbTiO3. Expressions from both models for the damping constants are fitted to the observed Raman linewidths of the two soft modes and for the other Raman modes the damping constant and the relaxation time are predicted close to the transition. We find that damping constants diverge and the inverse relaxation time decreases for the soft modes with increasing pressure near the critical pressure (P-c similar to 11 GPa). The other Raman modes exhibit unusual critical behavior. Our results indicate that the observed behavior of the Raman frequencies can be predicted from the volume data through the mode Gruneisen parameter for the tetragonal-cubic transition in PbTiO3. The damping constant and the relaxation time for the Raman modes can also be predicted adequately using the pseudospin-phonon coupled model and the energy fluctuation model to explain the mechanism of the phase transition between the tetragonal and cubic phases in PbTiO3
Calculation of the raman frequency, damping constant (Linewidth) and the relaxation time near the tetragonal-cubic transition in PbTiO3
(Elsevier GMBH, 2017) Kiracı, Ali; Yurtseven, H.; 42475
Frequencies, damping constants and the relaxation times of some Raman modes including the two soft modes are calculated as a function of pressure near the tetragonal-cubic transition in PbTiO3. Calculation of the Raman frequencies is performed using the observed volume data from the literature by means of the mode Gruneisen parameter at various pressures. Pressure dependence of the damping constant and the relaxation time is predicted using the pseudospin-phonon coupled model and the energy fluctuation model by considering that the Raman frequency can be taken as the order parameter (spontaneous polarization) for the tetragonal-cubic transition in PbTiO3. Expressions from both models for the damping constants are fitted to the observed Raman linewidths of the two soft modes and for the other Raman modes the damping constant and the relaxation time are predicted close to the transition. We find that damping constants diverge and the inverse relaxation time decreases for the soft modes with increasing pressure near the critical pressure (P-c similar to 11 GPa). The other Raman modes exhibit unusual critical behavior. Our results indicate that the observed behavior of the Raman frequencies can be predicted from the volume data through the mode Gruneisen parameter for the tetragonal-cubic transition in PbTiO3. The damping constant and the relaxation time for the Raman modes can also be predicted adequately using the pseudospin-phonon coupled model and the energy fluctuation model to explain the mechanism of the phase transition between the tetragonal and cubic phases in PbTiO3
Characterization of linear and nonlinear optical properties of NaBi(WO4)2 crystal by spectroscopic ellipsometry
(2024) Güler, İpek; Güler, İpek; Gasanly, N. M.; 101531
NaBi(WO4)2 compound has been a material of considerable attention in optoelectronic applications. The present research, in which we examined the linear and nonlinear optical properties of NaBi(WO4)2 crystal using the spectroscopic ellipsometry method, elucidates the optical behavior of the crystal in detail. Our work provides a sensitive approach to determine the spectral characteristic of the crystal. The spectral dependence of various optical parameters such as refractive index, extinction coefficient, dielectric function and absorption coefficient was reported in the range of 1.2-5.0 eV. Optical values such as bandgap energy, critical point energy, single oscillator parameters were obtained as a result of the analyses. In addition to linear optical properties, we also investigated the nonlinear optical behavior of NaBi(WO4)2 and shed new light on the potential applications of the crystal. Absorbance and photoluminescence spectra of the crystal were also reported to characterize optical, electronic and emission behavior of the compound. Our findings may form the basis for a number of technological applications such as optoelectronic devices, frequency conversion, and optical sensors. This research contributes to a better understanding of the optical properties of NaBi(WO4)2 crystal, highlighting the material's role in future optical and electronic technologies.

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