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Article Citation - WoS: 14Citation - Scopus: 14How Can We Get Benefits of Computer-Based Testing in Engineering Education?(Wiley, 2013) Cagiltay, Nergiz; Yaman, Seniz-Ozalp; Ozalp-Yaman, SenizUsing computers for assessment can provide several benefits for educators and test-takers. However, in the literature, there is no consensus on the equivalence of paper-and-pencil (P&P) and computer-based test (CBT) environments. Additionally, these studies fail to address the engineering domain. Our main assumption is that, if we could define the confounding factors to satisfy that these two versions of the tests provide equivalent results, then especially in the first year courses of the engineering education programs, we could get several benefits of the CBT environments. Accordingly, in this study, students' performance on different test modes was evaluated on 209 first year engineering students of a chemistry course. The results of this study showed that there is no significant performance difference between P&P and CBT. By comparing results with the previous studies, this study concludes that personal characteristics of test takers, the features of CBT systems, and the test content are all possible confounding factors when comparing test modes and need to be considered by the implementers. The results of this study show that once these factors are controlled, students' performance on CBTs and P&P tests in chemistry courses will not vary. This finding is encouraging the educators to get benefits of CBTs without any affect on students' performance. (c) 2010 Wiley Periodicals, Inc. Comput Appl Eng Educ 21: 287293, 2013; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.20470Article Citation - WoS: 11Citation - Scopus: 20Reinforcement Learning Using Fully Connected, Attention, and Transformer Models in Knapsack Problem Solving(Wiley, 2022) Yildiz, Beytullah; Yıldız, Beytullah; Yıldız, BeytullahKnapsack is a combinatorial optimization problem that involves a variety of resource allocation challenges. It is defined as non-deterministic polynomial time (NP) hard and has a wide range of applications. Knapsack problem (KP) has been studied in applied mathematics and computer science for decades. Many algorithms that can be classified as exact or approximate solutions have been proposed. Under the category of exact solutions, algorithms such as branch-and-bound and dynamic programming and the approaches obtained by combining these algorithms can be classified. Due to the fact that exact solutions require a long processing time, many approximate methods have been introduced for knapsack solution. In this research, deep Q-learning using models containing fully connected layers, attention, and transformer as function estimators were used to provide the solution for KP. We observed that deep Q-networks, which continued their training by observing the reward signals provided by the knapsack environment we developed, optimized the total reward gained over time. The results showed that our approaches give near-optimum solutions and work about 40 times faster than an exact algorithm using dynamic programming.Article Citation - WoS: 1Citation - Scopus: 1Left Ventricular Geometry as a Predictor of Carotid Artery Stenosis Severity in Patients Undergoing Carotid Artery Stenting(Wiley, 2020) Karaduman, Bilge Duran; Ayhan, Huseyin; Keles, Telat; Bozkurt, Engin; Duran Karaduman, BilgeBackground and Aim Cerebrovascular diseases are the second most common cause of death worldwide. Moderate and severe carotid artery stenosis causes nearly 10% of all strokes. LV geometry is a familiar prognostic and diagnostic factor in several populations; yet, data on its role in carotid artery stenosis are unknown. In our study, we investigated the prognostic value of LV geometry in predicting carotid artery stenosis severity in patients undergoing carotid artery stenting. Methods Patients who underwent carotid artery stenting between January 2012 and January 2016 at our tertiary care center were evaluated retrospectively. Two hundred fifty-five patients who underwent carotid artery stenting were included in the study. Accessible echocardiographic documentation of ninety-eight patients was accessed and evaluated. Results LV normal geometry was detected in 37 (37.7%) of the 98 carotid artery stenting (CAS) patients, concentric hypertrophy in 13 (13.2%), eccentric hypertrophy in 9 (9.1%), and concentric remodeling in 39 (39.7%). By a majority, distal filter was used in normal geometry and eccentric hypertrophy groups (82.9% vs 100%, P: .017). Considering the relationship between carotid artery stenosis severity and LV geometry, we determined that the stenosis severity was statistically significantly higher in the concentric hypertrophy group (p:0.012). However, although no complications were detected in the concentric hypertrophy group, it did not reach statistical significance between the groups (P: .058). LVMi and as expected, Doppler velocity showed a significant correlation with stenosis severity (r = .23 vs .54; P: .021, <.001, respectively). Conclusion Echocardiographic evaluation of LV geometry provided prognostic information in the development of carotid artery stenosis. Abnormal LV geometry is an independent predictor in detecting the severity of carotid artery stenosis undergoing carotid artery stenting.Article Citation - WoS: 19Citation - Scopus: 21Development of Effective Bimetallic Catalyst for High-Temperature Pem Fuel Cell To Improve Co Tolerance(Wiley, 2021) Al-Tememy, Mogdam Gassy Hussein; Devrim, YilserIn this study, it is aimed to examine the effect of multi-walled carbon nanotube doped graphene nanoplatelet (MWCNT-GNP) supported PtPd bimetallic catalyst on the performance of the high-temperature proton-exchange membrane fuel cell (HT-PEMFC). In addition, PtPd/GNP and PtPd/MWCNT bimetallic catalysts were also investigated for performance comparison. The characterizations of these catalysts were examined by ICP-MS, XRD, HR-TEM, and TGA analysis. The electrochemical characterizations of the catalysts were performed for both cyclic voltammetry (CV) and CO stripping experiments, as well as HT-PEMFC tests. The specific surface area (SSA) for PtPd/GNP and PtPd/MWCNT catalysts was obtained as 148 and 137 m(2)/g, respectively, while the highest SSA was achieved as 164 m(2)/g for PtPd/MWCNT-GNP. The performance of the catalysts was confirmed with the HT-PEMFC tests, based on the H-2/air and reformate gas/air experiments. The electrocatalytic results display that PdPt bimetallic catalysts exhibited higher catalytic property than that of commercial Pt/C catalyst. The highest performance was achieved with PtPd/MWCNT-GNP catalyst as 0.390 and 0.310 W/cm(2)at 160 degrees C for H-2/air and reformat/air, respectively. The obtained results indicate that the PtPd/MWCNT-GNP catalyst is appropriate for HT-PEMFC operations.Article Citation - WoS: 8Unexpected Event: Having an Infants With Cleft Lip And/Or Palate(Wiley, 2021) Cinar, Sevil; Ay, Ayse; Boztepe, Handan; Gurlen, EdaThis study aimed to determine the difficulties that the mothers of infants with a cleft lip and/or palate (CL/P) go through, the problems they encounter in this process, and how they perceive the support of healthcare professionals, families, and friends. The study used a phenomenological approach from qualitative research methods. The study sample included 18 mothers of 0 to 3-month-old infants with CL/P. The data were collected using socio-demographic information form and semi-structured interview form. The data obtained from the interviews were evaluated using content and thematic analysis approaches. On the basis of the interviews conducted with mothers of infants with CL/P, the following themes emerged: (a) "unexpected event: having an infant with CL/P," (b) "using social media," (c) "stigma," and (d) "uncertainty of long-term treatment." In this study, it was determined that mothers experienced shock, confusion, sadness, and disappointment in this process; therefore, they used social media to seek support from the families as well as conducted research on the disease that involved a lot of uncertainty due to long-term treatments. The present study can help healthcare professionals, who play a role in the care and treatment of infants with CL/P, to understand and know what mothers need in the preoperative period.Article Citation - WoS: 4Citation - Scopus: 5Stability Analysis of an Epidemic Model With Vaccination and Time Delay(Wiley, 2023) Turan, Mehmet; Adiguzel, Rezan Sevinik; Koc, F.; Sevinik Adıgüzel, RezanThis paper presents an epidemic model with varying population, incorporating a new vaccination strategy and time delay. It investigates the impact of vaccination with respect to vaccine efficacy and the time required to see the effects, followed by determining how to control the spread of the disease according to the basic reproduction ratio of the disease. Some numerical simulations are provided to illustrate the theoretical results.Conference Object Seroprevalence of Vaccine Preventable Viral Diseases and Vaccine Response Among Hiv Positive Patients(Wiley, 2019) Erdinc, F. S.; Dogan, K.; Tulek, N.; Ertem, G. Tuncer; Kinikli, S.[No Abstract Available]Article Citation - WoS: 21Citation - Scopus: 21Investigation of Hydrogen Production From Sodium Borohydride by Carbon Nano Tube-Graphene Supported Pdru Bimetallic Catalyst for Pem Fuel Cell Application(Wiley, 2022) Al-Msrhad, Tuqa Majeed Hameed; Devrim, Yilser; Uzundurukan, Arife; Budak, YagmurIn this study, hydrogen (H-2) generation from the hydrolysis of sodium borohydride (NaBH4) catalyzed by bimetallic Palladium-Ruthenium (PdRu) supported on multiwalled carbon nanotube-graphene (MWCNT-GNP) hybrid material is investigated. The effect of various parameters such as temperature, NaBH4 concentration, and catalyst loading and effect of base concentration are examined to observed optimum operating conditions. Experimental results show that the PdRu/MWCNT-GNP bimetallic catalyst has high catalytic activity on NaBH4 hydrolysis reaction. It has been found that PdRu/MWCNT-GNP catalyst shows low activation energy of 22.33 kJ/mol for hydrolysis reaction of NaBH4. The PdRu/MWCNT-GNP catalyst also exhibits H-2 generation rate of 79.2 mmol/min center dot g(cat) at 45 degrees C. It shows good cycle stability in the catalyst reusability test and retained 89% of its initial catalytic activity after fifth use. The high catalytic activity of the PdRu/MWCNT-GNP catalyst makes it promising in H-2 generation from NaBH4 hydrolysis for commercial proton exchange membrane fuel cell (PEMFC) applications.Article Citation - WoS: 26Citation - Scopus: 28Mean residual life of coherent systems consisting of multiple types of dependent components(Wiley, 2018) Eryilmaz, Serkan; Coolen, Frank P. A.; Coolen-Maturi, TahaniMean residual life is a useful dynamic characteristic to study reliability of a system. It has been widely considered in the literature not only for single unit systems but also for coherent systems. This article is concerned with the study of mean residual life for a coherent system that consists of multiple types of dependent components. In particular, the survival signature based generalized mixture representation is obtained for the survival function of a coherent system and it is used to evaluate the mean residual life function. Furthermore, two mean residual life functions under different conditional events on components' lifetimes are also defined and studied.Article Citation - WoS: 8Citation - Scopus: 15Distributed denial-of-service attack mitigation in network functions virtualization-based 5G networks using management and orchestration(Wiley, 2021) Koksal, Sarp; Dalveren, Yaser; Maiga, Bamoye; Kara, AliThe fifth generation (5G) technology is expected to allow connectivity to billions of devices, known as Internet of Things (IoT). However, IoT devices will inevitably be the main target of various cyberattack types. The most common one is known as distributed denial-of-service (DDoS) attack. In order to mitigate such attacks, network functions virtualization (NFV) has a great potential to provide the benefit of elasticity and low-cost solutions for protecting 5G networks. In this context, this study proposes a new mechanism developed to mitigate DDoS attacks in 5G NFV networks. The proposed mechanism utilizes intrusion prevention system's (IPS) virtual machines (VMs) to intercept the queries. Based on the volume of DDoS traffic, IPS's VMs are dynamically deployed by means of management and orchestration (MANO) in order to balance the load. To evaluate the effectiveness of the mechanism, experiments are conducted in a real 5G NFV environment built by using 5G NFV environment tools. To our best knowledge, this is the first time that NFV-based mechanism is experimentally tested in a real 5G NFV environment for mitigating DDoS attacks in 5G networks. The experimental results verify that the proposed mechanism can mitigate DDoS attacks effectively.
