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Permanent URI for this collectionhttps://ada.atilim.edu.tr/handle/123456789/19

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Citation Count: 1
Acceptance of Educational Use of AI Chatbots in the Context of Self-Directed Learning with Technology and ICT Self-Efficacy of Undergraduate Students
(Taylor & Francis inc, 2024) Esiyok, Elif; Gokcearslan, Sahin; Kucukergin, Kemal Gurkan; Tourism Management; Public Relations and Advertising
For long now, the use of Artificial Intelligence (AI) chatbots in higher education to support and engage learners in classroom learning activities has been attracting the attention of researchers. The acceptance of this technology for learning purposes is indicative of learners' intentions and actual use in the future. Hence, this study aims to test the educational use of AI chatbots in the context of self-directed learning with technology (SDLT) along with information and communication technology (ICT) self-efficacy, using the extended Technology Acceptance Model (TAM). The study involved 414 undergraduate students, and the research model was tested by utilizing the Partial Least Square Structural Equation Model (PLS-SEM). The results indicate that ICT self-efficacy affects only the perceived ease of use (PEU), whereas PEU and perceived usefulness have a positive effect on the intention to use AI chatbots. Moreover, SDLT is shown to affect both the intention and the actual use of AI chatbots. As such, it is suggested - among other notes - that universities update their curricula and activities to support SDLT, and also organize activities in order to increase ICT self-efficacy among students.
Citation Count: 31
Adoption of mobile applications for teaching-learning process in rural girls' schools in India: an empirical study
(Springer, 2020) Chatterjee, Sheshadri; Majumdar, Dipasree; Misra, Sanjay; Damasevicius, Robertas; Computer Engineering
The purpose of this study is to identify the factors that can impact the adoption of mobile apps for teaching-learning process focusing on the girls' school in rural India. The hypotheses were proposed and a conceptual model has been developed. There is a survey work conducted to collect the data from different respondents using a convenience sampling method. The model has been validated statistically through PLS-SEM analysis covering feedbacks of 271 effective respondents. The study highlights the impact of different antecedents of the behavioural intention of the students of using mobile applications for teaching-learning process. The results also show that among other issues, price value has insignificant influence on the intention of the girl students of the rural India. During survey feedbacks have been obtained from the 271 respondents, which is meagre compared to vastness of the population and school of rural India. Only few predictors have been considered leaving possibilities of inclusion of other boundary conditions to enhance the explanative power more than that has been achieved in the proposed model with the explanative power of 81%. The model has provided laudable inputs to the educational policy makers and technology enablers and administrators to understand the impact of the mobile applications on the rural girls' school of India and facilitate the development of m-learning. Very few studies been conducted to explore the impact of mobile applications on the school education of rural India especially focusing on the girls' schools.
Citation Count: 0
Advanced 3D printed bone scaffolds with sodium alginate/Tri-calcium phosphate/probiotic bacterial hydroxyapatite: Enhanced mechanical and biocompatible properties for bone tissue engineering
(Elsevier Sci Ltd, 2024) Nouri, Sabereh; Emtiazi, Giti; Ulag, Songul; Gunduz, Oguzhan; Koyuncu, Ayse Ceren Calikoglu; Roghanian, Rasoul; Sasmazel, Hilal Turkoglu; Metallurgical and Materials Engineering
Introduction: The increasing prevalence of severe bone diseases, such as osteoporosis and critical bone defects, necessitates the development of more effective bone substitutes. This study addresses this need by investigating 3D-printed bone scaffolds composed of sodium alginate and tricalcium phosphate, enhanced with three distinct types of hydroxyapatite (HA): bovine-derived HA, commercially available HA, and HA enriched with probiotic bacteria. We aim to evaluate the performance of these scaffolds in terms of mechanical strength, biocompatibility, and their ability to support bone regeneration. Methods: The scaffolds were analyzed through various tests, including X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) to characterization. Scanning Electron Microscopy (SEM) was used to examine pore structure, while swelling and degradation tests evaluated the scaffold's stability. Compression testing determined mechanical strength, and in vitro cell culture assays assessed cell proliferation, osteogenic differentiation, and biomineralization. Results: SEM results indicated that 3D scaffolds with probiotic bacterial HA had the desired 472 mu m pore size. These scaffolds demonstrated a strain of 29.26 % and a compressive strength of 10 MPa, meeting the mechanical standards of human trabecular bone. Cell culture studies revealed enhanced cell proliferation by 50 %, osteogenic differentiation with 15.3 U/mg ALP activity, and 1.22-fold biomineralization, suggesting they are highly biocompatible and promote bone growth. Conclusion: Probiotic bacterial HA scaffolds exhibit ideal properties and biocompatibility, enhancing bone regeneration and serving as an ideal alternative to chemical types.
Citation Count: 6
Al/CdSe/GaSe/C resonant tunneling thin film transistors
(Elsevier Science Bv, 2017) Qasrawi, A. F.; Kayed, T. S.; Elsayed, Khaled A.; Department of Electrical & Electronics Engineering
An Al/CdSe/GaSe/C thin film transistor device was prepared by the physical vapor deposition technique at a vacuum pressure of 10(-5) mbar. The x-ray diffraction measurements demonstrated the polycrystalline nature of the surface of the device. The de current-voltage characteristics recorded for the Al/CdSe/C and Al/CdSe/GaSe/C channels displayed a resonant tunneling diode features during the forward and reverse voltage biasing, respectively. In addition, the switching current ratio of the Al/CdSe/C increased from 18.6 to 9.62x10(3) as a result of the GaSe deposition on the CdSe surface. Moreover, the alternating electrical signal analyses in the frequency range of 1.0 MHz to 1.8 GHz, showed some remarkable properties of negative resistance and negative capacitance spectra of the AVCdSe/GaSe/C thin film transistors. Two distinct resonance-antiresonance phenomena in the resistance spectra and one in the capacitance spectra were observed at 0.53, 1.04 and 1.40 GHz for the Al/CdSe/C channel, respectively. The respective resonating peak positions of the resistance spectra shift to 0.38 and 0.95 GHz when GaSe is interfaced with CdSe. These features of the thin film transistors are promising for use in high quality microwave filtering circuits and also for use as ultrafast switches.
Citation Count: 7
Algorithm for adaptive learning process and improving learners' skills in Java programming language
(Wiley, 2018) Gavrilovic, Nebojsa; Arsic, Aleksandra; Domazet, Dragan; Mishra, Alok; Software Engineering
Adaptive approaches within distance learning systems enable adapting teaching process to the needs of each learner during the learning process. This paper presents an algorithm for creating an adaptive learning process that provides knowledge and skills improvement for learners in the Java programming language. Also, it presents the application of the tool that checks the learner's knowledge through solving practical tasks from the Java programming language. The adaptive learning process in this work leads the learner through teaching materials and practical tasks where the acquired knowledge is required to be applied. Also, the algorithm, based on the measurement of knowledge and time spent on a particular part of the learning process with detailed feedback and the demonstration of observed deficiencies, directs the learner to teaching materials that allow improving the demonstrated knowledge. Teaching materials are conceived as learning objects and, as such, allow for the application of adaptive approach. An analysis of the effectiveness of the algorithm and tool for practical knowledge testing from the Java programming language was done with a test group of learners who gave their opinions and grades.
Citation Count: 75
Analysis of P_c⁺(4380) and P_c⁺(4450) as pentaquark states in the molecular picture with QCD sum rules
(Amer Physical Soc, 2017) Azizi, K.; Sarac, Y.; Sundu, H.; Physics Group
To better understand the nature and internal structure of the exotic states discovered by many collaborations, more information on their electromagnetic properties and their strong and weak interactions with other hadrons is needed. The residue or current coupling constant of these states together with their mass are the main inputs in determinations of such properties. We perform QCD sum rules analyses on the hidden-charm pentaquark states with spin parities J(P) = 3/2 (+/-) and J(P) = 5/2 (+/-) to calculate their residue and mass. In the calculations, we adopt a molecular picture for J(P) = 3/2(+/-) states and a mixed current in a molecular form for J(P) = 5/2(+/-). Our analyses show that the P-c(+) (4380) and P-c(+) (4450), observed by the LHCb Collaboration, can be considered as hidden-charm pentaquark states with J(P) = 3/2(-) and JP = 5/2(+), respectively.
Citation Count: 23
An analysis of course characteristics, learner characteristics, and certification rates in MITx MOOCs
(2020) Cagiltay,N.E.; Cagiltay,K.; Celik,B.; Department of Basic English (Prep School)
Massive Open Online Courses (MOOCs), capable of providing free (or low cost) courses for millions of learners anytime and anywhere, have gained the attention of researchers, educational institutions, and learners worldwide. Even though they provide several benefits, there are still some criticisms of MOOCs. For instance, MOOCs' high dropout rates or predominantly elite participation are considered to be important problems. In order to develop solutions for these problems, a deeper understanding of MOOCs is required. Today, despite the availability of several research studies about MOOCs, there is a shortage of in-depth research on course characteristics, learner characteristics, and predictors of certification rates. This study examined MOOC and learner characteristics in detail and explored the predictors of course certification rates based on data from 122 Massachusetts Institute of Technology MOOCs (MITx) on edX platform as well as data about the 2.8 million participants registered in these MOOCs. The results indicated that as the number of courses offered and the number of learners enrolled increased in years, there was a decrease in the certification rates among enrolled learners. According to our results, the number of average chapters completed, total forum messages, and mean age predicted course certification rates positively. On the other hand, the total number of chapters in a course predicted the course certification rates negatively. Based on these results, shorter and more interactive MOOCs are recommended by considering the needs of the learners, course content design, and strategies encouraging the enrolled students to enter the courses. © 2020, Athabasca University.
Citation Count: 3
Analysis of the Junction Properties of C/GaSe_0.5S_0.5/C Back-to-Back Schottky-Type Photodetectors
(Ieee-inst Electrical Electronics Engineers inc, 2015) Khanfar, Hazem K.; Qasrawi, Atef F.; Gasanly, Nizami M.; Department of Electrical & Electronics Engineering
In this paper, a C/GaSe0.5S0.5/C metal-semiconductor-metal photodetector is suggested and described. The device is explored by means of current-voltage and capacitance-voltage (C-V) characteristics under different photoexcitation intensities. It was observed that the design of the back-to-back Schottky device has reduced the dark current of the normal Ag/GaSe0.5S0.5/C Schottky diode by 13 times and increased the photosensitivity from 3.8 to similar to 2.1x10(3). The device exhibited a barrier height of 0.842 eV in the dark. The barrier height is reduced via photoexcitation. In addition, the C/GaSe0.5S0.5/C device exhibited an ON/OFF switching property from low injection OFF to high injection ON at specific biasing voltages. This voltage decreased with the increasing illumination intensity. On the other hand, the C-V characteristics of the device, which was recorded for an ac input signal with 100 MHz at different levels of photoexcitation shifted up when the intensity of light was increased. When the same measurement was repeated at signal frequency of 1.6 GHz, the C-V characteristics reflected a different level of capacitance response. These features of C/GaSe0.5S0.5/C photodetectors nominate the device to be used as multipurpose optical switches being suitable to store different levels of electromagnetic energy at microwave frequencies.
Citation Count: 10
Analysis of the strong D₂* (2460)⁰ → D⁺ π^- and D_s2*(2573)⁺ → D⁺ K⁰ transitions via QCD sum rules
(Springer, 2014) Azizi, K.; Sarac, Y.; Sundu, H.; Physics Group
The strong D-2* (2460)(0) -> D+ pi(-) and D-s2* (2573)(+) -> D+ K-0 transitions are analyzed via three-point QCD sum rules. First we calculate the corresponding strong coupling constants g(D2)*D pi and g(Ds2)*DK. Then we use them to calculate the corresponding decay widths and branching ratios. Making use of the existing experimental data on the ratio of the decay width in the pseudoscalar D channel to that of the vector D* channel, finally, we estimate the decay width and branching ratio of the strong D-2(*) (2460)(0) -> D*(2010)(+)pi(-) transition.
Citation Count: 16
ANALYTICAL SOLUTIONS TO VARIABLE THICKNESS AND VARIABLE MATERIAL PROPERTY ROTATING DISKS FOR A NEW THREE-PARAMETER VARIATION FUNCTION
(Taylor & Francis inc, 2012) Argeso, Hakan; Manufacturing Engineering
Analytical solutions of two different annular rotating disk problems are obtained under the assumptions of plane stress, isotropy, and small deformations. The first problem involves a homogeneous variable profile disk, whereas the second one is a functionally graded disk having a variation in elasticity modulus. For the variations of disk thickness and elasticity modulus in these problems, a new form of nonlinear function controlled by three parameters is introduced. The derivations of the closed form solutions for both type of rotating disk problems are carried out in a unified form. The closed form solutions are verified numerically by the nonlinear shooting method.
Citation Count: 14
Analyzing the role of constraints and motivations behind traveling in the prediction of destination choice: Evidence from PLS-SEM and fsQCA
(Wiley, 2021) Kucukergin, Kemal Gurkan; Caliskan, Caner; Dedeoglu, Bekir Bora; Birinci, Muhammet Cenk; Tourism Management
This study aims to examine the relationship among travel constraints, travel motivations, and destination choice via a multi-method approach. For this purpose, two studies and two analysis tools-PLS-SEM and fsQCA-were employed to conduct examinations in the context of two different target destinations (France and China). Findings revealed that travel constraints and travel motivations generally influenced destination choice. However, it was found that PLS-SEM and fsQCA results were not compatible for some relationships. In light of this and further findings, it was observed that the matter of destination choice is complex by nature.
Citation Count: 6
Anatomy of a failed IMF program: The 1999 program in Turkey
(M.E. Sharpe Inc., 2004) Çapoǧlu,G.
This paper analyzes the failed IMF program in Turkey that was initiated in December 1999. The 1999 Turkish exchange rate-based stabilization program was presented as an improved version of earlier programs implemented in Latin American countries. The inclusion of an exit strategy was considered as an innovative element of the Turkish program. However, the program crashed fourteen months after its initiation. This paper argues that the Turkish program underestimated the possible negative impact of unfavorable initial conditions, especially conditions of an institutional nature, which turned out to be a fatal mistake. Among the conditions that were ignored by the 1999 program were the absence of an independent and effective regulatory agency in the banking sector and the circumstances under which the Treasury carried out its borrowing.
Citation Count: 22
Anomaly detection using fuzzy Q-learning algorithm
(Budapest Tech Polytechnical Institution, 2014) Shamshirband,S.; Anuar,N.B.; Kiah,M.L.M.; Misra,S.; Computer Engineering
Wireless networks are increasingly overwhelmed by Distributed Denial of Service (DDoS) attacks by generating flooding packets that exhaust critical computing and communication resources of a victim's mobile device within a very short period of time. This must be protected. Effective detection of DDoS attacks requires an adaptive learning classifier, with less computational complexity, and an accurate decision making to stunt such attacks. In this paper, we propose an intrusion detection system called Fuzzy Q-learning (FQL) algorithm to protect wireless nodes within the network and target nodes from DDoS attacks to identify the attack patterns and take appropriate countermeasures. The FQL algorithm was trained and tested to establish its performance by generating attacks from the NSL-KDD and CAIDA DDoS Attack datasets during the simulation experiments. Experimental results show that the proposed FQL IDS has higher accuracy of detection rate than Fuzzy Logic Controller and Q-learning algorithm alone. © 2014 Instituto de Pesquisas Economicas da FEA-USP. All rights reserved.
Citation Count: 0
Anticipatory effect of execution on observation: an approach using ExoPinch finger robot
(Tubitak Scientific & Technological Research Council Turkey, 2019) Arıkan, Kutluk Bilge; Zadeh, Hassan Gol Mohammad; Turgut, Ali Emre; Zinnuroğlu, Murat; Bayer, Gözde; Günendi, Zafer; Cengiz, Bülent; Department of Mechatronics Engineering
Background/aim: This study aims to explore the mirror neuron system (MNS) involvement using mu (8–12 Hz)/beta (15–25 Hz) bandsuppression in an action observation-execution paradigm.Materials and methods: Electrophysiological (EEG) data from 16 electrodes were recorded while 8 participants observed video clips ofa hand squeezing a spring. Specifically, the effect of anticipated execution on observation was studied. For this purpose, a fully actuatedfinger exoskeleton robot was utilized to synchronize observation and execution and to control the execution condition for the participants. Anticipatory effect was created with a randomized robot accompany session.Results: The results showed that the observational condition (with or without anticipation) interacted with hemisphere at central channels near somatosensory cortex. Additionally, we explored the response of MNS on the kinetics features of visual stimuli (hard or softspring).Conclusion: The results showed an interaction effect of kinetics features and hemisphere at frontal channels corresponding nearly tothe ventral premotor cortex area of the brain. The activation of mirror neurons in this area plays a crucial role in observational learning.Based on our results, we propose that specific type of visual stimuli can be combined with the functional abilities of the MNS in the action observation based treatment of hand motor dysfunction of stroke patients to have a positive additional impact.
Citation Count: 12
Antisolvent-fumigated grain growth of active layer for efficient perovskite solar cells
(Pergamon-elsevier Science Ltd, 2021) Sajid, Sajid; Khan, Suliman; Khan, Ayub; Khan, Danish; Issakhov, Alibek; Park, Jongee; Metallurgical and Materials Engineering
High efficiency of perovskite solar cell can be obtained through various approaches, including materials and interface engineering, device modification and fabrication techniques. In all approaches, the quality of the perovskite layer has a significant impact on the efficiency of the perovskite solar cell. Antisolvent dripping is widely used in almost all fabrication methodologies to achieve a high-quality perovskite layer. However, in the conventional antisolvent dripping, there are several factors (antisolvent volume, time and point of dripping, etc.) to be strictly followed. Due to these difficult and critical tricks, researchers often get perovskite layers with pinholes, small grains, and wide grain boundaries that deteriorate the performance of the perovskite solar cells. In order to produce perovskite films with large-scale grains, narrow boundaries and smooth surface morphology, a sealed antisolvent-fumigated process is implemented. There is no need to make any substantial efforts to achieve optimal conditions for the fabrication of high-quality perovskite layers using the antisolvent-fumigated strategy. Consequently, the efficiency of perovskite solar cell improves dramatically from 18.65% to 21.45%. Our findings present a new and convenient method for fabricating highly efficient perovskite solar cells.
Citation Count: 5
Applying model-driven paradigm for the improvement of web requirement validation
(2012) Aragon,G.; Escalona,M.J.; Hilera,J.R.; Fernandez-Sanz,L.; Misra,S.; Computer Engineering
This paper proposes an approach for Web requirements validation by applying the model-driven paradigm in classical requirements validation techniques. In particular, we present how the Navigational Development Techniques (NDT) approach exploits the model-driven paradigm to improve its requirements validation task by exploring tool cases that systematize or even automate the application of requirements validation techniques. Our solution is validated by applying it in a real industrial environment. The results and the learned lessons are presented accordingly.
Citation Count: 11
An approach for e-Commerce on-demand service-oriented product line development
(Budapest Tech Polytechnical Institution, 2013) Ezenwoke,A.; Misra,S.; Adigun,M.; Computer Engineering
The growth of Small, Medium and Micro Enterprises (SMMEs) is important to the economic development of Africa. This growth can be greatly enhanced by leveraging IT in business activities since e-commerce is a vital tool to allow participation in globalization. Many SMMEs cannot afford to own e-commerce facilities and to reduce cost. An SMME can pay for just the e-commerce facility they use without owning the services or infrastructure. Due to the dynamic nature of the business domain, delivering such on-demand functionalities involves high flexibility in adapting to new client requirements; therefore, a systematic approach to software component reuse must be adopted to reduce cost and the time to market for new products. This work explores the reuse capabilities of a hybridization of Service Oriented Architecture (SOA) and Software Product Line (SPL).
Citation Count: 15
An approach for the empirical validation of software complexity measures
(2011) Misra,S.; Computer Engineering
Software metrics are widely accepted tools to control and assure software quality. A large number of software metrics with a variety of content can be found in the literature; however most of them are not adopted in industry as they are seen as irrelevant to needs, as they are unsupported, and the major reason behind this is due to improper empirical validation. This paper tries to identify possible root causes for the improper empirical validation of the software metrics. A practical model for the empirical validation of software metrics is proposed along with root causes. The model is validated by applying it to recently proposed and well known metrics.
Citation Count: 9
The approximation of logarithmic function by q-Bernstein polynomials in the case q > 1
(Springer, 2007) Ostrovska, Sofiya; Mathematics
Since in the case q > 1, q-Bernstein polynomials are not positive linear operators on C[ 0, 1], the study of their approximation properties is essentially more difficult than that for 0 < q < 1. Despite the intensive research conducted in the area lately, the problem of describing the class of functions in C[ 0, 1] uniformly approximated by their q-Bernstein polynomials ( q > 1) remains open. It is known that the approximation occurs for functions admitting an analytic continuation into a disc {z : | z| < R}, R > 1. For functions without such an assumption, no general results on approximation are available. In this paper, it is shown that the function f ( x) = ln( x + a), a > 0, is uniformly approximated by its q-Bernstein polynomials ( q > 1) on the interval [ 0, 1] if and only if a >= 1.
Citation Count: 0
Aptamer-based magnetic isolation and specific detection system for Listeria monocytogenes from food samples
(Elsevier, 2024) Bayramoglu, Gulay; Ozalp, Veli Cengiz; Arica, Mehmet Yakup; Basic Sciences
In this work, an aptamer-based magnetic system was designed for specific and rapid detection of Listeria monocytogenes in food samples. To prepare the selective magnetic system against the target bacterium, firstly, magnetic particles (Fe3O4) were coated with two hydrophilic polymer layers. The specific aptamer immobilized magnetic system efficiently captured L. monocytogenes cells in a competitive response time of approximately 10 min. The magnetic aptamer detection system was very specific to L. monocytogenes and had high selective, up to 97.6 % compared to the Listeria species (Listeria ivanovii, Listeria innocua, and Listeria seeligeri) and other bacteria species Escherichia coli, Staphylococcus aureus, and Basillus subtilus. The isolation and detection of L. monocytogenes from food samples using the presented method are fast and reliable. Moreover, another significant factor to be contemplated is the use of a few chemicals for detection, reducing the cost of analysis, and the results can be obtained within 18 h.

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