Ortak Dersler Bölümü

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Citation - WoS: 2
Citation - Scopus: 3
Analysis of the Integrated Intensity of the Central Peaks Calculated as a Function of Temperature in the Ferroelectric Phase of Lithium Tantalate
(Vinca inst Nuclear Sci, 2018) Yurtseven, Hamit; Kiraci, Ali; 42475; 09.01. Ortak Dersler Bölümü; 09. Rektörlük; 01. Çankaya Üniversitesi
The integrated intensity of the central peak is calculated as a function of temperature in the ferroelectric phase (T < T-C) of nearly stoichiometric LiTaO3. This calculation is performed using the temperature dependence of the order parameter obtained from the mean field theory at temperatures lower than the transition temperature T-C (T-C = 963 K) of this crystal. The calculated values of the order parameter (squared) are fitted to the integrated intensity of the central peaks as observed from the Raman and Brillouin scattering experiments as reported in the literature in the ferroelectric phase of nearly stoichiometric LiTaO3. Our results are in good agreement with the observed behavior of LiTaO3 crystal. Because of the applications of LiTaO3 in several academic disciplines including the material science and thermal science, it is beneficial to investigate dynamic properties of this crystal such as the damping constant, inverse relaxation time and the activation energy as also we studied here.
Citation - WoS: 8
Citation - Scopus: 8
Analysis of the Specific Heat and the Free Energy of [N(ch3)4]2znbr4 Close To the Ferro-Paraelastic Phase Transition
(Taylor & Francis Ltd, 2019) Kiraci, A.; 42475; 09.01. Ortak Dersler Bölümü; 09. Rektörlük; 01. Çankaya Üniversitesi
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.
Citation - WoS: 21
Citation - Scopus: 25
Classification Models Based on Tanaka's Fuzzy Linear Regression Approach: the Case of Customer Satisfaction Modeling
(Ios Press, 2010) Sekkeli, Gizem; Koksal, Gulser; Batman, Inci; Bayrak, Ozlem Turker; 56416; 09.01. Ortak Dersler Bölümü; 09. Rektörlük; 01. Çankaya Üniversitesi
Fuzzy linear regression (FLR) approaches are widely used for modeling relations between variables that involve human judgments, qualitative and imprecise data. Tanaka's FLR analysis is the first one developed and widely used for this purpose. However, this method is not appropriate for classification problems, because it can only handle continuous type dependent variables rather than categorical. In this study, we propose three alternative approaches for building classification models, for a customer satisfaction survey data, based on Tanaka's FLR approach. In these models, we aim to reflect both random and fuzzy types of uncertainties in the data in different ways, and compare their performances using several classification performance measures. Thus, this study contributes to the field of fuzzy classification by developing Tanaka based classification models.
Citation - WoS: 4
Citation - Scopus: 8
Creating Infographics Based on the Bridge21 Model for Team-Based and Technology-Mediated Learning
(informing Science inst, 2019) Sullivan, Kevin; Akkoyunlu, Buket; Nuhoglu-Kibar, Pinar; 8539; 09.01. Ortak Dersler Bölümü; 09. Rektörlük; 01. Çankaya Üniversitesi
Aim/Purpose The main aim of this study was modeling a collaborative process for knowledge visualization, via the creation of infographics. Background As an effective method for visualizing complex information, creating infographics requires learners to generate and cultivate a deep knowledge of content and enables them to concisely visualize and share this knowledge. This study investigates creating infographics as a knowledge visualization process for collaborative learning situations by integrating the infographic design model into the team-based and technology-mediated Bridge21 learning model. Methodology This study was carried out using an educational design perspective by conducting three main cycles comprised of three micro cycles: analysis and exploration; design and construction; evaluation and reflection. The process and the scaffolding were developed and enhanced from cycle to cycle based on both qualitative and quantitative methods by using the infographic design rubric and researcher observations acquired during implementation. Respectively, twenty-three, twenty-four, and twenty-four secondary school students participated in the infographic creation process cycles. Contribution This research proposes an extensive step-by-step process model for creating infographics as a method of visualization for learning. It is particularly relevant for working with complex information, in that it enables collaborative knowledge construction and sharing of condensed knowledge. Findings Creating infographics can be an effective method for collaborative learning situations by enabling knowledge construction, visualization and sharing. The Bridge21 activity model constituted the spine of the infographic creation process. The content generation, draft generation, and visual and digital design generation components of the infographic design model matched with the investigate, plan and create phases of the Bridge21 activity model respectively. Improvements on infographic design results from cycle to cycle suggest that the revisions on the process model succeeded in their aims. The rise in each category was found to be significant, but the advance in visual design generation was particularly large. Recommendations for Practitioners The effectiveness of the creation process and the quality of the results can be boosted by using relevant activities based on learner prior knowledge and skills. While infographic creation can lead to a focus on visual elements, the importance of wording must be emphasized. Being a multidimensional process, groups need guidance to ensure effective collaboration. Recommendation for Researchers The proposed collaborative infographic creation process could be structured and evaluated for online learning environments, which will improve interaction and achievement by enhancing collaborative knowledge creation. Impact on Society In order to be knowledge constructors, innovative designers, creative communicators and global collaborators, learners need to be surrounded by adequate learning environments. The infographic creation process offers them a multidimensional learning situation. They must understand the problem, find an effective way to collect information, investigate their data, develop creative and innovative perspectives for visual design and be comfortable for using digital creation tools. Future Research The infographic creation process could be investigated in terms of required learner prior knowledge and skills, and could be enhanced by developing pre-practices and scaffolding.
Citation - WoS: 5
Citation - Scopus: 5
Determination of Trapping Parameters of Tl2in2s3se Layered Single Crystal by Thermoluminescence
(Wiley-v C H verlag Gmbh, 2018) Gasanly, Nizami; Guler, Ipek; 101531; 01. Çankaya Üniversitesi; 09. Rektörlük; 09.01. Ortak Dersler Bölümü
Thermoluminescence (TL) measurements are performed to evaluate the trap states in Tl2In2S3Se layered single crystals. TL experiments are conducted with varying temperature from 10 to 300 K and warming rates from 0.2 to 1.0 K s(-1). From the analysis of both initial rise and curve fitting methods, the activation energy of the traps is obtained as 23 meV. The Chen's method is also used to find activation energy. By means of this technique, the activation energy of the TL glow curve is calculated as 25 meV. From both Chen's method and curve fitting method, the existence of mixed order of kinetics in Tl2In2S3Se crystal is found. The cross section to capture of the trap center is found out from the results of curve fitting method. The trap distribution of the crystals is investigated with different temperatures of illumination at a constant warming rate of 0.8 K s(-1). The temperatures of illumination change from 10 to 22 K. As a result of the increase in temperatures of illumination, the peak maximum values move to higher temperatures and intensity of the TL curves decreases. This behavior shows us that quasicontinuous traps distribution is present in Tl2In2S3Se layered single crystals.
An Exploration of the Landscape of Instructional Design: Understanding Changes and Pandemic Effects (2017-2022)
(Ozgen Korkmaz, 2024) Akkoyunlu, B.; Yilmaz, Y.Y.; Bardakci, S.; 8539; 09.01. Ortak Dersler Bölümü; 09. Rektörlük; 01. Çankaya Üniversitesi
The purpose of this study is to examine the scope of the field of instructional design and technology, along with the working area (desk) of the expert in this field, in the context of the effects of the pandemic. The study is a bibliographic mapping research. The data set includes bibliographic records of 2.397 scientific texts retrieved from the WOS Core Collection within the time range of 2017-2022 using search terms instructional design or instructional designer. Co-occurrence analyses encompassing author keywords were conducted on the data. As a result, maps and related outputs were obtained that reveal the concepts that the field focused on before and after the pandemic, as well as the relationships between these. Additionally, attempts were made to identify emerging concepts for both periods based on the outputs. According to the results, there has been a significant expansion in the concepts falling within the scope of instructional design and technology, and consequently in the roles and responsibilities of designers, in conjunction with the 2020s and the Covid-19 pandemic. Design concepts and variables, context, human factors, and research methodology are enriched within this expansion. This enrichment shifts the design process from a micro perspective focusing on learning environment and environmental variables to a macro perspective that emphasizes instructors, educational institutions, and culture. Within this perspective, while the weight of real instructional problems increases, the emphasis on theory, approach, and models significantly decreases. © 2024, Ozgen Korkmaz. All rights reserved.
Citation - Scopus: 30
Fostering and Assessing Infographic Design for Learning: the Development of Infographic Design Criteria
(Taylor and Francis Ltd., 2017) Akkoyunlu, B.; Nuhoğlu Kibar, P.; 8539; 09.01. Ortak Dersler Bölümü; 09. Rektörlük; 01. Çankaya Üniversitesi
In this ever more digital and visual world, it has become more vital that students are encouraged to create content during the learning process through effective visualization of their knowledge. Infographics are an effective method for such visualization. The current study therefore proposes an infographic design rubric (IDR) as a criteria-based framework to be used in the learning process for the creation and evaluation of infographics. The IDR was developed based on the infographic design model (IDM), a process of how to design infographics for teachers and learners using the three main components of content generation, visual design generation and digital design. The development process was conducted in the five design cycles of criteria determination, validity and reliability studies involving colleagues, university students, pre-service teachers and teachers. IDR criteria were generated based on content generation and visual design generation dimensions of IDM. The content generation dimension focuses on the quality and organization of the information presented, while the visual design generation dimension investigates the visual features of the infographic. Results of the inter-rater reliability analysis represent significant intraclass correlations. The proposed IDR is considered to be an important step for visualization in the learning process. © 2017, © 2017 International Visual Literacy Association.
Citation - Scopus: 1
Linear Contrasts in One-Way Classification Ar(1) Model With Gamma Innovations
(Hacettepe Univ, Fac Sci, 2016) Senoglu, Birdal; Bayrak, Ozlem Turker; 56416; 09.01. Ortak Dersler Bölümü; 09. Rektörlük; 01. Çankaya Üniversitesi
In this study, the explicit estimators of the model parameters in oneway classification AR(1) model with gamma innovations are derived by using modified maximum likelihood (MML) methodology. We also propose a new test statistic for testing linear contrasts. Monte Carlo simulation results show that the MML estimators have higher efficiencies than the traditional least squares (LS) estimators and the proposed test has much better power and robustness properties than the normal theory test.
Citation - WoS: 3
Citation - Scopus: 7
Modeling of Infographic Generation Process as a Learning Strategy at the Secondary School Level Based on the Educational Design Research Method
(Turkish Education Assoc, 2018) Akkoyunlu, Buket; Kibar, Pinar Nuhoglu; 8539; 09.01. Ortak Dersler Bölümü; 09. Rektörlük; 01. Çankaya Üniversitesi
The study aimed to model an infographic design process for the use of infographics as a learning strategy at the secondary school level. A progressive model was suggested in line with a hypothetical perspective regarding the infographic generation process in order to enable learners to resolve and visualize complex information. Using educational design research methodology, the research took place over three meso cycles each comprised of micro cycles: the first two meso cycles included the micro-cycles of analysis and exploration, design and construction and evaluation and reflection and the third meso cycle the evaluation and reflection micro cycle. The study was conducted in collaboration with Information Technology, Science and Technology and Visual Arts teachers and with the participation of 18 7th grade students in the first meso cycle and 19 7th-grade students in the second meso cycle. The infographic design process and the reached infographic design levels were evaluated using the infographic design rubric, reflection forms and focus group interview. Based on the evaluation results obtained at the end of the first two meso cycles, the infographic design process was redesigned and developed. The infographic design process was designed to include the steps of content acquisition, infographic design information, content preparation, content generation, visual design generation, draft generation and digital design in the first meso cycle. In accordance with evaluations, the second meso cycle preserved these steps and implemented a spiral structure to replace the progressive structure of the first meso cycle. Sub-stages were added to meet the determined needs to the infographic design process, training activities were increased and a greater length of time was given for the digital design step. In accordance with the reflection obtained throughout the process, laboratory computers used in the design process in the first cycle were replaced with the students' own tablets in the second. The infographic design levels and reflections reached in the second meso cycle indicated that the arrangements made in the infographic design process developed the process. At the end of the comprehensive evaluation undertaken in the third meso cycle, a conclusion was reached that the collaboration between different fields, infographic design experience and the use of learners' own instruments was significant. This study can be distinguished from other relevant studies as it presents a comprehensive process model in accordance with the educational design research method which contains applications within itself regarding the implementation of infographic design strategy in the learning process.
Citation - WoS: 3
Citation - Scopus: 3
N-Phosphorylation of Pyrroles: an Intramolecular Migration Reaction
(Pergamon-elsevier Science Ltd, 2018) Unaleroglu, Canan; Tasgin, Dilek Isik; 09.01. Ortak Dersler Bölümü; 09. Rektörlük; 01. Çankaya Üniversitesi
A new synthetic method is reported for the N-phosphorylation of pyrroles via intramolecular migration of a phosphonate diester group. The reaction proceeds under mild conditions and produces N-phosphorylated pyrrole derivatives in moderate to good yields. (C) 2018 Elsevier Ltd. All rights reserved.
Citation - WoS: 2
Citation - Scopus: 2
Phenomenological Study of Manganese Antimonite Close To the Neel Temperature
(Ieee-inst Electrical Electronics Engineers inc, 2021) Kiraci, Ali; 09.01. Ortak Dersler Bölümü; 09. Rektörlük; 01. Çankaya Üniversitesi
The anomalous behavior of the frequency f and specific heat C-p data for the new layered trigonal (P (3) over bar 1m) form of manganese antimonite (MnSb2O6) was analyzed by means of the power-law relations with the critical exponent alpha in the vicinity of the Neel temperature of T-N= 8.0 K. While the extracted values of a from both f and C-p below T-N (the same value of 0.06) match exactly the value 1/16 (= 0.06) predicted from the three-dimensional (3-D) Ising model, the extracted value of 0.65 from the C-p data above T-N is much higher than the predicted value of 1/8 (= 0.13) from the 3-D Ising model. As an extension of this work, the temperature dependence of the muon-spin relaxation rate (damping constant) lambda of MnSb2O6 was calculated from the pseudospin-phonon-coupled (PS) model and the energy fluctuation (EF) model below T-N. Our results are in good agreement with the data. In addition, the activation energy was calculated from the predicted values of. from both PS and EF models for MnSb2O6. Our results indicate an order-disorder-type transition at T-N = 8.0 K for MnSb2O6.
Citation - WoS: 5
Citation - Scopus: 6
Ring Annulation Versus Alkylation of Pyrrole With Α-Phosphoryl Ketones
(Pergamon-elsevier Science Ltd, 2016) Tasgin, Dilek Isik; Unaleroglu, Canan; 16910; 09.01. Ortak Dersler Bölümü; 09. Rektörlük; 01. Çankaya Üniversitesi
In this study; novel aryl, heteroaryl, pyrrolyl and phosphoryl groups containing pyrrolizines were synthesized by the ring annulation reaction of aryl or heteroaryl substituted alpha-phosphoryl-alpha,beta-unsaturated ketones with pyrrole under mild reaction conditions. This domino reaction involves scandium triflate catalyzed addition of pyrrole to the double bond of alpha-phosphoryl-alpha,beta-unsaturated ketones, carbonyl group and finally ring annulation sequences. The presented work provided a convenient way for the synthesis of novel bispyrrolic compounds. (C) 2016 Elsevier Ltd. All rights reserved.
Citation - WoS: 7
Citation - Scopus: 7
A Theoretical Investigation: Effect of Structural Modifications on Molecular, Electronic, and Optical Properties of Phosphonate Substituted Bodipy Dyes
(Wiley-v C H verlag Gmbh, 2021) Tasgin, Dilek Isik; Sirin, Pinar Seyitdanlioglu; 169107; 09.01. Ortak Dersler Bölümü; 09. Rektörlük; 01. Çankaya Üniversitesi
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, alpha, or alpha, alpha '-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 alpha, and alpha, alpha '-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 (E-gap) (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.

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