WoS İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12469/4465

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Citation - WoS: 22
Citation - Scopus: 34
A Quality-of-Service-Aware Service Composition Method in the Internet of Things Using a Multi-Objective Fuzzy-Based Hybrid Algorithm
(Mdpi, 2023) Hamzei, Marzieh; Khandagh, Saeed; Navimipour, Nima Jafari
The Internet of Things (IoT) represents a cutting-edge technical domain, encompassing billions of intelligent objects capable of bridging the physical and virtual worlds across various locations. IoT services are responsible for delivering essential functionalities. In this dynamic and interconnected IoT landscape, providing high-quality services is paramount to enhancing user experiences and optimizing system efficiency. Service composition techniques come into play to address user requests in IoT applications, allowing various IoT services to collaborate seamlessly. Considering the resource limitations of IoT devices, they often leverage cloud infrastructures to overcome technological constraints, benefiting from unlimited resources and capabilities. Moreover, the emergence of fog computing has gained prominence, facilitating IoT application processing in edge networks closer to IoT sensors and effectively reducing delays inherent in cloud data centers. In this context, our study proposes a cloud-/fog-based service composition for IoT, introducing a novel fuzzy-based hybrid algorithm. This algorithm ingeniously combines Ant Colony Optimization (ACO) and Artificial Bee Colony (ABC) optimization algorithms, taking into account energy consumption and Quality of Service (QoS) factors during the service selection process. By leveraging this fuzzy-based hybrid algorithm, our approach aims to revolutionize service composition in IoT environments by empowering intelligent decision-making capabilities and ensuring optimal user satisfaction. Our experimental results demonstrate the effectiveness of the proposed strategy in successfully fulfilling service composition requests by identifying suitable services. When compared to recently introduced methods, our hybrid approach yields significant benefits. On average, it reduces energy consumption by 17.11%, enhances availability and reliability by 8.27% and 4.52%, respectively, and improves the average cost by 21.56%.
Citation - WoS: 17
Citation - Scopus: 20
In Silico Design of Novel and Highly Selective Lysine-Specific Histone Demethylase Inhibitors
(Scientific Technical Research Council Turkey-Tubitak, 2011) Akdoğan, Ebru Demet; Erman, Burak; Yelekçi, Kemal
Histone lysine-specific demethylase (LSD1) is involved in a wide range of epigenetic processes and plays important roles in gene silencing DNA transcription DNA replication DNA repair and heterochromatin formation. Its active site shows a resemblance to those of 2 homologous enzymes monamine oxidase A and B (MAO-A and MAO-B.) In the present work starting from suitable scaffolds and generating thousands of structures from them 10 potential inhibitors were obtained with structural and physicochemical properties selectively suitable for inhibiting LSD1. iLib Diverse software was used to generate the diverse structures and 3 docking tools CDOCKER GOLD and AutoDock were used to find the most probable potential inhibitor based on its binding affinity. The dispositions of the candidate molecules within the organism were checked by ADMET_PSA_2D (polar surface area) versus ADMET_AlogP98 (the logarithm of the partition coefficient between n-octanol and water) and their suitability is discussed. The LSD1 inhibition activities of the candidates were compared with the properties of trans-2-phenylcyclopropylamine (tranylcypromine) and 2-(4-methoxy-phenyl) cyclopropylamine which are the 2 known inhibitors of LSD1.
Citation - WoS: 145
Citation - Scopus: 145
Psychological Correlates of Covid-19 Conspiracy Beliefs and Preventive Measures: Evidence From Turkey
(Springer, 2020) Alper, Sinan; Bayrak, Fatih; Yılmaz, Onurcan
COVID-19 pandemic has led to popular conspiracy theories regarding its origins and widespread concern over the level of compliance with preventive measures. In the current preregistered research, we recruited 1088 Turkish participants and investigated (a) individual differences associated with COVID-19 conspiracy beliefs; (2) whether such conspiracy beliefs are related to the level of preventive measures; and (3) other individual differences that might be related to the preventive measures. Higher faith in intuition, uncertainty avoidance, impulsivity, generic conspiracy beliefs, religiosity, and right-wing ideology, and a lower level of cognitive reflection were associated with a higher level of belief in COVID-19 conspiracy theories. There was no association between COVID-19 conspiracy beliefs and preventive measures while perceived risk was positively and impulsivity negatively correlated with preventive measures. We discuss the implications and directions for future research.
Citation - WoS: 21
Citation - Scopus: 22
Design of Practical Broadband Matching Networks With Lumped Elements
(IEEE-INST Electrical Electronics Engineers Inc, 2013) Şengül, Metin Y.
It is always preferable to use commercially available software tools to design broadband matching networks for microwave communication systems. However for these tools the matching network topology and element values must be selected properly. Therefore in this paper a practical method is presented to generate matching networks with good initial element values. Eventually the performance of the designed matching network is optimized by employing the commercially available computer-aided design (CAD) tools. An example is given to illustrate the utilization of the proposed method. It is shown that the proposed method provides very good initials for CAD tools.
Citation - WoS: 21
Citation - Scopus: 20
"it Was as If Society Didn't Want a Woman To Get an Abortion": a Qualitative Study in Istanbul Turkey
(Elsevier Science Inc, 2017) MacFarlane, Katrina A.; O'Neil, Mary Lou; Tekdemir, Deniz; Foster, Angel M.
Introduction: In 1983 abortion without restriction as to reason was legalized in Turkey. However at an international conference in 2012 the Prime Minister condemned abortion and announced his intent to draft restrictive abortion legislation. As a result of public outcry and protests the law was not enacted but media reports suggest that barriers to abortion access have since worsened. Objectives: We aimed to conduct a qualitative study exploring women's recent abortion experiences in Istanbul Turkey. Study design: In 2015 we conducted 14 semi-structured in-depth interviews with women aged 18 or older who had obtained abortion care in Istanbul on/after January 1 2009. We employed a multimodal recruitment strategy and analyzed these interviews for content and themes using deductive and inductive techniques. Results: Women reported on a total of 19 abortions. Although abortion care is available in private facilities only one public hospital provides abortion services without restriction as to reason. Women who had multiple abortions in different facility types described quality of care more positively in the private sector. Unmarried women considered their marital status when making the decision to seek an abortion and reported challenges obtaining comprehensive sexual and reproductive health services. All participants were familiar with the Turkish government's antiabortion discourse and believed that this was reflective of an overarching desire to restrict women's rights. Conclusion: Public abortion services in Istanbul are currently limited and private abortion services are accessible but relatively expensive to obtain. Recent antiabortion political rhetoric appears to have negatively impacted access and service quality. Implications: This is the first qualitative study exploring women's experiences obtaining abortion services in Turkey since the proposed abortion restriction in 2012. Further research exploring the experiences of unmarried women and abortion accessibility in other regions of the country is warranted. (C) 2017 Elsevier Inc. All rights reserved.
Citation - WoS: 5
Citation - Scopus: 4
The Availability of Emergency Contraception From Family Health Centers in Turkey
(Elsevier Ireland Ltd, 2022) O'Neil, Mary Lou; Aldanmaz, Bahar; Altuntas, Deniz
Reproductive health care, including contraception, is a fundamental aspect of any public health care system and it is important to reduce barriers to access to all forms of contraception, including emergency contraception. In recent years, the rhetoric of pronatalism in Turkey has come to dominate and raises questions about the availability of reproductive health care services, in particular contraception, from state run facilities. This study aimed to determine the availability of dedicated emergency contraception (EC) from government run Family Health Centers (FHCs) in Turkey. In 2019, a team of trained researchers called a random sample of 583 FHCs located in the largest cities in twelve regions across Turkey asking for dedicated EC. Dedicated EC is largely unavailable from government supported FHCs. Only 6.1% stated that they provided EC while 53.8% stated that it was not available and that they could provide no alternative. A further 28.3% declared that they could provide an alternative to dedicated EC that almost always consisted of oral contraceptives. We found statistically significant variations in response rate and availability among cities as well as the rate of referral to pharmacies. There is little access to EC from government sponsored health clinics designated to provide family planning services, which hinders access to an essential reproductive health care service that should be available to women everywhere.
Citation - WoS: 13
Citation - Scopus: 14
Energy-Saving Behavior of Turkish Women: a Consumer Survey on the Use of Home Appliances
(Sage Publications Ltd, 2017) Ucal, Meltem Şengün
This paper focuses on energy-related attitudes and behaviors of Turkish women who are the main users of electrical home appliances responsible for most household energy consumption. Answers from 1323 female respondents surveyed through a unique questionnaire formed the dataset. The results from analysis of variance show that education has a significant effect on the relationship between energy saving and awareness and attitudes about climate change. Significant differences also exist between education level groups in terms of knowledge of the classification of energy-saving electrical home appliances. Responses to questions related to energy-saving purchasing behaviors are consistently higher for knowledgeable respondents. The paper then uses factor analysis and ordinal logit models to reveal interactions between energy-saving behavior regarding electrical home appliances and several factors namely awareness sensitivity essentials and receptiveness. The identification of these factors can provide useful insights for policy makers that enable them to construct energy-saving policies specifically tailored toward women.
Citation - WoS: 9
Citation - Scopus: 8
Daily and Intraday Herding Within Different Types of Investors in Borsa Istanbul
(Routledge Journals, Taylor & Francis Ltd, 2019) Dalgıç, Nihan; Ekinci, Cumhur; Ersan, Oğuz
This paper aims to explore the daily and intraday herd behavior of various investor groups trading in an emerging equity market, Borsa Istanbul (BIST). We analyze a one-year tick-by-tick order and trade data of BIST 100 Index stocks and document differences in herding behavior of investor groups considering market capitalization, market conditions, and announcements as well as daily and intraday periodicities. We find that nonprofessional investors (brokerage houses and domestic funds) tend to herd on large (small) stocks; their herding behavior mostly exhibits a U shape (an inverse U shape) during the day. All types of investors tend to herd in down markets on a daily basis while this behavior disappears, even inverts intraday.
Citation - WoS: 4
Citation - Scopus: 12
Allocation of Distributed Generators Using Parallel Grey Wolf Optimization
(IEEE, 2021) Younesi, Soheil; Ahmadi, Bahman; Ceylan, Oguzhan; Ozdemir, Aydogan
This paper solves the allocation problem of distributed generators (DGs) in smart grids utilizing a grey wolf optimization (GWO) algorithm. By parallelizing GWO, it presents the impact of using various number of processors on speedup, efficiency. To decrease the computation time required to perform the simulations, different migration rates are applied for different number of processors. Moreover, the accuracy obtained using different number of processors is analyzed. The simulations are performed for a 33-bus distribution test system using MATLAB's parallel computing toolbox. From the simulation results it is observed that parallel GWO can be used as a tool for distribution system optimization.
Citation - WoS: 7
Citation - Scopus: 6
Investigation of Pst-Mwcnt Concentration on Epoxyacrylate Photopolymerization and Conductivity of Polymer Films
(Elsevier Science SA, 2013) Doğruyol, Zekeriya; Temel, Gökhan; Doğruyol, Sevnur Keskin; Pekcan, Önder; Arsu, Nergis
Photopolymerization kinetics and conductivity changes of epoxyacrylate composites for various loading modified PSt-MWCNT weight fractions changing from 0.0025 to 0.2 wt.% were evaluated by performing photo differential scanning calorimetry (photo-DSC) and four point conductivity measurements. 0.2% PSt-MWCNT additive polymeric films had their electrical conductivity boosted by 6% more than non-additive polymeric films. (C) 2012 Elsevier B.V. All rights reserved.
Citation - WoS: 2
Citation - Scopus: 2
Assessing the Renewable Energy Sources for Sustainable Energy Generation Systems: Interval-Valued Q-Rung Orthopair Fuzzy SWARA-TOPSIS
(Elsevier Ltd, 2026) Faruk Görçün, Ö.F.; Aytekin, A.; Selçuk Korucuk, S.; Tirkolaee, E.B.
Renewable Energy Sources (RESs) help decarbonize power systems, but selecting among them is a challenging decision problem due to multiple, often conflicting, technical, economic, environmental, and health-related criteria. Consequently, numerous studies in the literature have attempted to address this decision-making issue using objective, subjective, and fuzzy decision-making procedures. However, there are still unaddressed research gaps in the literature, particularly regarding the explicit modeling of expert hesitation and ambiguity in real-world RES selection cases. The current study develops a decision-making model based on Step-wise Weight Assessment Ratio Analysis (SWARA) and Technique of Order Preference Similarity to the Ideal Solution (TOPSIS) methods integrated with Interval-Valued q-Rung Orthopair Fuzzy Sets (IV-q-ROFSs) to fill these gaps. Unlike previous studies that have predominantly applied conventional fuzzy MCDM techniques, our model introduces the first integration of IV-q-ROFS into RES selection. This novelty enables a more accurate representation of expert hesitation and uncertainty. The study is applied to a real industrial case in Turkey, where six RES alternatives are evaluated across 43 criteria by five senior experts under the supervision of a three-member professionals’ board. Furthermore, the structured robustness check and systematic literature mapping ensure that the proposed approach is methodologically robust and practically relevant for policymakers and energy planners. The application results of the developed model demonstrate that the estimated energy production potential of the RES and the effects of carcinogens generated from utilizing these energy sources are the critical factors influencing the selection of the most appropriate RESs. Solar energy ranked first among the alternatives. The applicability and validity of the developed model are examined by a comprehensive robustness check consisting of tests of sensitivity, comparison, and resilience to the rank reversal problem. Overall, the study provides (i) a novel methodological framework integrating IV-q-ROFS with SWARA and TOPSIS, (ii) empirical evidence from a comprehensive real-world RES selection case, and (iii) policy-relevant insights into the drivers of renewable energy adoption. © 2025 Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
Citation - WoS: 27
Citation - Scopus: 26
Network Structural Origin of Instabilities in Large Complex Systems
(Amer Assoc Advancement Science, 2022) Duan, Chao; Nishikawa, Takashi; Eroglu, Deniz; Motter, Adilson E.
A central issue in the study of large complex network systems, such as power grids, financial networks, and ecological systems, is to understand their response to dynamical perturbations. Recent studies recognize that many real networks show nonnormality and that nonnormality can give rise to reactivity-the capacity of a linearly stable system to amplify its response to perturbations, oftentimes exciting nonlinear instabilities. Here, we identify network structural properties underlying the pervasiveness of nonnormality and reactivity in real directed networks, which we establish using the most extensive dataset of such networks studied in this context to date. The identified properties are imbalances between incoming and outgoing network links and paths at each node. On the basis of this characterization, we develop a theory that quantitatively predicts nonnormality and reactivity and explains the observed pervasiveness. We suggest that these results can be used to design, upgrade, control, and manage networks to avoid or promote network instabilities.
Citation - Scopus: 1
Ieee 802.15.4a Based Ultra Wideband Systems for Coexistence With Primary Users
(IEEE, 2015) Fındıklı, Çağlar; Erküçük, Serhat; Çelebi, Mehmet Ertuğrul
Peaceful coexistence is a major implementation issue for both cognitive radios and ultra wideband (UWB) systems. Accordingly the UWB impulse radio (UWB-IR) based Wireless Personal Area Network (WPAN) standard IEEE 802.15.4a has suggested using linear combination of pulses to limit interference to coexisting primary systems. In this paper motivated by implementing the IEEE 802.15.4a based UWB-IR systems for peaceful coexistence we consider the implementation of linear combination of pulses as suggested by the standard. Accordingly we (I) design linearly combined pulses that conform to the standard requirements and (ii) study the UWB-IR system performance in the presence of orthogonal frequency division multiplexing (OFDM) based wideband primary systems with various bandwidths and subcarriers. The study shows that the UWB-IR system performance can be significantly improved by selecting suitable pulses for transmission and employing appropriate filtering techniques at the receiver when the primary system is active. The results are important for the practical implementation of IEEE 802.15.4a based UWB systems coexisting with licensed systems.
Citation - WoS: 8
Citation - Scopus: 11
Does mood affect institutional herding?
(Elsevier, 2020) Gavriilidis, Konstantinos; Kallinterakis, Vasileios; Öztürkkal, Belma
Drawing on a unique data set of daily portfolio holdings for Turkish mutual funds we investigate the relationship between mood and institutional herding on the premises of various established mood proxies (weekend effect; holiday effect; Ramadan; sunshine). Results indicate that fund managers in Turkey herd significantly, with their herding growing in magnitude as the number of active funds per stock rises and appearing stronger on the buy-than the sell-side. Although the relationship of mood with institutional herding occasionally assumes the correct sign as per theoretical expectations, institutional herding is found to be insignificantly different across various mood states, thus denoting that mood does not impact the propensity of fund managers to herd. (C) 2020 Elsevier B.V. All rights reserved.
Citation - WoS: 37
Citation - Scopus: 40
Joint Optimization of Wireless Network Energy Consumption and Control System Performance in Wireless Networked Control Systems
(IEEE-INST Electrical Electronics Engineers Inc, 2017) Şadi, Yalçın; Ergen, Sinem Coleri
Communication system design for wireless networked control systems requires satisfying the high reliability and strict delay constraints of control systems for guaranteed stability with the limited battery resources of sensor nodes despite the wireless networking induced non-idealities. These include non-zero packet error probability caused by the unreliability of wireless transmissions and non-zero delay resulting from packet transmission and shared wireless medium. In this paper we study the joint optimization of control and communication systems incorporating their efficient abstractions practically used in real-world scenarios. The proposed framework allows including any non-decreasing function of the power consumption of the nodes as the objective any modulation scheme and any scheduling algorithm. We first introduce an exact solution method based on the analysis of the optimality conditions and smart enumeration techniques. Then we propose two polynomial-time heuristic algorithms based on intelligent search space reduction and smart searching techniques. Extensive simulations demonstrate that the proposed algorithms perform very close to optimal and much better than previous algorithms at much smaller runtime for various scenarios.
Citation - WoS: 13
Citation - Scopus: 15
An Integrated Fuzzy Best-Worst Method for Evaluation of Hotel Website and Digital Solutions Provider Firms
(Hindawi Limited, 2020) Samanlıoğlu, Funda; Burnaz, Ayşe Nur; Diş, Berke; Tabaş, Mehmet Doğukan; Adıgüzel, Mehmet
In todays world where technology is rapidly evolving, hotels need to be the best in all conditions to be one step ahead of other competitors. Digital marketing and hotel website solutions play a lead role in this competition. Therefore, hotel websites need to be innovative, user-friendly, and descriptive. The main purpose of the study is to evaluate and rank potential hotel websites and digital solutions provider firms. Since there are various potentially competing quantitative and qualitative criteria to take into consideration in the decision-making process, a multicriteria decision-making (MCDM) method is needed. As the MCDM method, fuzzy best-worst method (FBWM) is integrated with the Fuzzy Technique for Order Preference by Similarity to Ideal Solution (F-TOPSIS). In this integration, FBWM is applied to determine fuzzy evaluation criteria weights and then F-TOPSIS is implemented to rank alternatives utilizing the obtained fuzzy weights. A case study is presented, where 4 alternative hotel websites and digital solutions provider firms for Paloma Hotels in Turkey are evaluated based on 9 criteria by 3 hotel managers.
Citation - WoS: 1
Citation - Scopus: 1
A Qualitative Study of Unveiling School Dropout Complexity in Türkiye
(Springer, 2024) Ozdemir, Nurten Karacan; Kemer, Fatma Nur Aras; Arslan, Arif; Tuna, Burak
This study investigates school dropout, particularly the shift to open high schools in Turkiye during the pandemic, through a multi-stakeholder lens. Using grounded theory, data was collected via semi-structured interviews with 12 students, 15 teachers, and 20 school administrators. Results reveal a model linking themes: predictive reasons for transferring to open high school, both pandemic-related and unrelated, positive/negative consequences of the transition, pandemic's impact on formal education continuity, essential open high school skills, and strategies to reduce such preferences. Findings highlight the sway of exam-focused education on open high school interest, regardless of COVID-19, and emphasize the need for equitable education amidst Turkiye's pandemic challenges. Theoretical implications may infer the necessity of approaching school dropout as a multilayered dynamic issue within the cultural context. The implications also may convey the significance of policies and systems not only to reduce the rates of school dropout but also critically unpack underlying reasons to make improvements.
Citation - WoS: 2
Jejunojejunal Intussusception Secondary To Lipoma in an Adult -: a Case Report
(Blackwell Munksgaard, 2002) Çakirer, S; Sirvanci, M; Duran, C
Lipoma is a rare cause of adult intussusception. We present the CT findings of an adult patient with jejunojejunal intussusception secondary to submucosal lipoma as the lead point in this case report.
Citation - WoS: 23
Citation - Scopus: 25
Holocene coastal change in the ancient harbor of Yenikapi-Istanbul and its impact on cultural history
(Academic Press Inc Elsevier Science, 2011) Algan, Oya; Yalçın, M. Namık; Özdoğan, Mehmet; Yılmaz, Yücel; Sari, Erol; Kirci-Elmas, Elmas; Yılmaz, Isak; Bulkan, Özlem; Ongan, Demet; Gazioğlu, Cem; Nazik, Atike; Polat, Mehmet Ali; Meriç, Engin
An extensive rescue excavation has been conducted in the ancient harbor of Istanbul (Yenikapi) by the Sea of Marmara revealing a depositional sequence displaying clear evidence of transgression and coastal progradation during the Holocene. The basal layer of this sequence lies at 6 m below the present sea level and contains remains of a Neolithic settlement known to have been present in the area indicating that the sea level at similar to 8-9 cal ka BP was lower than 6 m below present. Sea level advanced to its maximum at similar to 6.8-7 cal ka BP drowning Lykos Stream and forming an inlet at its mouth. After similar to 3 cal ka BP coastal progradation became evident. Subsequent construction of the Byzantine Harbor (Theodosius \4th century AD) created a restricted small basin and accumulation of fine-grained sediments. The sedimentation rate was increased due to coastal progradation and anthropogenic factors during the deposition of coarse-grained sediments at the upper parts of the sequence (7th-9th centuries AD). The harbor was probably abandoned after the 11th century AD by filling up with Lykos Stream detritus and continued seaward migration of the coastline. (C) 2011 University of Washington. Published by Elsevier Inc. All rights reserved.
Citation - WoS: 15
Citation - Scopus: 15
Rapidly Time-Varying Channel Estimation for Full-Duplex Amplify-And One-Way Relay Networks
(IEEE-INST Electrical Electronics Engineers Inc, 2018) Şenol, Habib; Li, Xiaofeng; Tepedelenlioglu, Cihan
Estimation of both cascaded and residual self-interference (RSI) channels and a new training frame structure are considered for full-duplex (FD) amplify-and-forward (AF) one-way relay networks with rapidly time-varying individual channels. To estimate the RSI and the rapidly time-varying cascaded channels we propose a new training frame structure in which orthogonal training blocks are sent by the source node and delivered to the destination over an FD-AF relay. Exploiting the orthogonality of the training blocks we obtain two decoupled training signal models for the estimation of the RSI and the cascaded channels. We apply linear minimum mean square error (MMSE) based estimators to the cascaded channel as well as RSI channel. In order to investigate the mean square error (MSE) performance of the system we also derive the Bayesian Cramer-Rao lower bound. As another performance benchmark we also assess the symbol error rate (SER) performances corresponding to the estimated and the perfect channel state information available at the receiver side. Computer simulations exhibit the proposed training frame structure and the linear MMSE estimator MSE and SER performances are shown.

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