Scopus İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12469/1248

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Citation - WoS: 1
Citation - Scopus: 1
6-Point Tripled Ashkin-Teller Global Phase Diagrams in Two and Three Dimensions
(Elsevier, 2025) Zeynioglu, Deniz Ipek; Berker, A. Nihat
The tripled Ashkin-Teller model including 6-point interactions is solved in d = 2 and 3 by renormalization-group theory that is exact on the hierarchical lattice and approximate on the recently first/second-order-transition improved Migdal-Kadanoff procedure. Five different ordered phases occur in the dimensionally distinct global phase diagrams. 16 different phase diagram cross-sections in the 2-point and 4-point interaction space are obtained, with first-and second-order phase transitions, multiple tricritical points and critical endpoints.
Citation - WoS: 3
Citation - Scopus: 2
Acceptable 'expats Versus Unwanted 'arabs Tracing Hierarchies Through Everyday Urban Practices of Skilled Migrant Women in Istanbul
(Wiley, 2024) Tuncer, Ezgi
This article focuses on ethnic hierarchies found within highly educated migrant women working in Istanbul traced through their everyday urban practices. It introduces the stratified and comparative results of migration and resettlement of those from the Global North and the Global South through a comprehensive analysis on their urban lives, including their social positionings, preferences of neighbourhoods and daily patterns of their use of the city. Contrary to the common conception that skilled migrants are privileged, our research reveals inequalities and discriminatory practices they face that intersect with gender, nationality and ethnicity. Our research, based on qualitative analyses of in-depth interviews along with online subjective mapping representing use of the city, also reveals that regardless of their origin and identity, almost all our participants experience verbal/physical sexual harassment or discrimination in public space in Istanbul, which forces women to produce spatial tactics of everyday life.
Citation - WoS: 2
Citation - Scopus: 3
Achieving Sustainability in Solar Energy Firms in Turkey Through Adopting Lean Principles
(Mdpi, 2022) Aldewachi, Bilal; Ayag, Zeki
Lean principles and sustainability are considered important terms in business. Solar firms are witnessing great competition to fulfill energy requirements, suffering from a huge amount of waste, negatively affecting the sustainability dimensions. Thus, the aim of the study is to build a framework for solar energy firms to achieve sustainability through adopting lean principles, which will help to fix many problems as waste and costs. The method included reviewing the literature to explore the founding of the relation between the two terms, and using a questionnaire that was directed to the responsible people in Turkish solar energy firms. The results of the survey were analyzed to: (1) Find out what the responsible people think about the two terms lean and sustainability; (2) Measure the probable relationship between lean principles and sustainability dimensions by applying a linear regression test; (3) Use the results of point number two to build the framework. The result showed there was a high level of relative importance about the two terms from the point of view of managers and experts in solar firms. In addition, the study found a relationship between adopting pull and flow principles of lean, and achieving economic and social dimensions of sustainability, this finding is represented in a framework.
Acoustic Assessment of Four Music Rehearsal Rooms in Accordance With ISO23591 Standard
(Elsevier Sci Ltd, 2025) Saher, Konca; Ozgencil, Yalin; Khoshkholghi, Solmaz
Optimizing rehearsal room acoustics is crucial for musicians to perceive sound, pitch, and frequency variations. Since the introduction of the international standard ISO 23591 Acoustic quality criteria for music rehearsal rooms and spaces, research in the field of music rehearsal rooms has significantly intensified. However, relatively few have adopted an approach that integrates both objective measurements and subjective user evaluations, particularly in rehearsal rooms for quiet-category instruments. Therefore, this study aimed to assess and improve the acoustical conditions of four Turkish rehearsal rooms for quiet-category instruments using measurements, simulations, and musician surveys. A survey conducted in the first phase revealed that musicians rated the efficiency, satisfaction, and frequency balance of four rehearsal rooms as bad to fair. Efficiency of rehearsals showed a strong correlation with frequency balance (R2 = 0.72 for low-to-mid; R2 = 0.76 for high-to-mid). Strong correlations (R2 = 0.93) were found between calculated and perceived low-to-mid frequency balance, while high-to-mid frequency balance showed weaker correlations (R2 = 0.36), suggesting possible sensitivity to low-frequency issues; though this did not consistently align with user satisfaction, indicating that additional perceptual factors play a role. Acoustic measurements show that existing reverberation time (RTmid) values for all rooms fall outside recommended limits. The measured rehearsal rooms were modeled, calibrated, and 36 acoustic models were developed with three alternative designs to improve acoustics within recommended limits. Then musicians from these rooms assessed 36 acoustic models through listening tests based on auralizations. Listening tests showed a preference for models with RTmid values within the recommended range, aligning subjective and objective assessments. After the RTmid value, effect of low-to-mid frequency balance was important in the choice of rooms for musicians.
Citation - WoS: 2
Citation - Scopus: 3
Active and Reactive Power Load Profiling Using Dimensionality Reduction Techniques and Clustering
(Institute of Electrical and Electronics Engineers Inc., 2019) Yetkin, E. Fatih; Ceylan, Oğuzhan; Papadopoulos, Theofilos A.; Kazaki, Anastasia G.; Barzegkar-Ntovom, Georgios A.
This paper proposes a methodology to characterize active and reactive power load profiles. Specifically, the approach makes use of fast Fourier Transform for conversion into frequency domain, principle component analysis to reduce the dimension and K-means++ to determine the representative load profiles. The data set consists of five-year measurements taken from the Democritus University of Thrace Campus. Test days were also classified as working and non-working. From the results it is observed that the proposed methodology determines representative load profiles effectively both regarding active and reactive power.
Citation - Scopus: 18
Actively open- minded thinking and the political effects of its absence
(Oxford University Press, 2023) Baron, J.; Isler, O.; Yilmaz, O.
[No abstract available]
Citation - Scopus: 12
Acute Gastrointestinal Complications After Open Heart Surgery
(Asia Publishing Exchange Pte Ltd, 2000) Akpınar, Belhhan; Sağbaş, Ertan; Güden, Mustafa; Kemertas, Kubilay; Sönmez, Bingür; Bayındır, Osman; Demiroğlu, Cemşid
Retrospective analysis revealed that 24 of 4401 adult patients (0.5%) developed severe gastrointestinal complications after open heart surgery during a 3-year period from January 1995. There were 4 women (17%) and 20 men (83%). Mean age was 61.7 ± 2.02 years. Gastrointestinal bleeding (33.3%) mesenteric ischemia (20.8%) pancreatitis (20.8%) hepatic dysfunction (16.7%) and cholecystitis (16.7%) were the most common complications. Mortality was 41.7% (10 patients). During the same period mortality in the patients who did not develop gastrointestinal complications was 1.89% (p < 0.0001). Emergency basis reoperation combined operations peripheral vascular disease diabetes mellitus chronic lung disease and impaired left ventricle function were found to be risk factors for the development of postoperative gastrointestinal complications.
Adaptation To Nocturnal Intermittent Hypoxia in Sleep-Disordered Breathing: 2,3 Diphosphoglycerate Levels: a Preliminary Study
(2002) Öztürk, Levent Mukadder; Mansour, Banu; Pelin, Zerrin; Çelikoğlu, Firuz; Gökhan, Nuran
An inexpensive method for determining significant sleep-related hypoxemia would be beneficial for patients being investigated and treated for sleep-disordered breathing in order to distinguish hypoxic patients from those without nocturnal hypoxemia. Since 2,3 diphosphoglycerate (DPG) which profoundly affects dissociation of O2 from hemoglobin is an instrumental substance in determining the O2 affinity of blood it becomes important to consider in what extent the nocturnal intermittent hypoxemia may change the levels of 2,3 DPG. In this study we tested the hypothesis that 2,3 DPG levels of hypoxic SDB patients may be higher than that of nonhypoxic SDB patients and normal controls. Fourteen SDB patients were participated the study seven with hypoxia (hypoxic group) who spent more than 10 minutes during sleep with SaO2<90% (mean 71 minutes) and seven SDB patients (nonhypoxic group) who spent less than 10 minutes during sleep with SaO2<90% (mean 6 minutes). Seven healthy non-smoking subjects were included as a control group. After giving informed consent all participants underwent a venous blood sampling performed between 07:00 and 08:00 a.m. Blood 2,3 DPG levels were measured by using spectrophotometry. 2,3 DPG levels were 1.84±0.44 1.68±0.18 and 1.71±0.11 mmol/mL in hypoxic nonhypoxic and control groups respectively (p>0.05). In conclusion to our knowledge this is the first study that has evaluated 2,3 DPG levels in hypoxic and nonhypoxic types of SDB patients. Chronic intermittent hypoxia which is entirely a different entity from sustained hypoxia did not lead to increases in 2,3 DPG levels in both hypoxic and nonhypoxic SDB patients.
Citation - WoS: 21
Citation - Scopus: 31
Adoption of Mobile Health Apps in Dietetic Practice: Case Study of Diyetkolik
(Jmır Publıcatıons, Inc, 130 Queens Quay E, 2020) Akdur, Görkem; Aydın, Mehmet Nafiz; Akdur, Gizdem
Background: Dietetics mobile health apps provide lifestyle tracking and support on demand. Mobile health has become a new trend for health service providers through which they have been shifting their services from clinical consultations to online apps. These apps usually offer basic features at no cost and charge a premium for advanced features. Although diet apps are now more common and have a larger user base, in general, there is a gap in literature addressing why users intend to use diet apps. We used Diyetkolik, Turkey's most widely used online dietetics platform for 7 years, as a case study to understand the behavioral intentions of users. Objective: The aim of this study was to investigate the factors that influence the behavioral intentions of users to adopt and use mobile health apps. We used the Technology Acceptance Model and extended it by exploring other factors such as price-value, perceived risk, and trust factors in order to assess the technology acceptance of users. Methods: We conducted quantitative research on the Diyetkolik app users by using random sampling. Valid data samples gathered from 658 app users were analyzed statistically by applying structural equation modeling. Results: Statistical findings suggested that perceived usefulness (P<.001), perceived ease of use (P<.001), trust (P<.001), and price-value (P<.001) had significant relationships with behavioral intention to use. However, no relationship between perceived risk and behavioral intention was found (P=.99). Additionally, there was no statistical significance for age (P=.09), gender (P=.98), or previous app use experience (P=.14) on the intention to use the app. Conclusions: This research is an invaluable addition to Technology Acceptance Model literature. The results indicated that 2 external factors (trust and price-value) in addition to Technology Acceptance Model factors showed statistical relevance with behavioral intention to use and improved our understanding of user acceptance of a mobile health app. The third external factor (perceived risk) did not show any statistical relevance regarding behavioral intention to use. Most users of the Diyetkolik dietetics app were hesitant in purchasing dietitian services online. Users should be frequently reassured about the security of the platform and the authenticity of the platform's dietitians to ensure that users' interactions with the dietitians are based on trust for the platform and the brand.
Citation - WoS: 1
Citation - Scopus: 2
Aesthetic Approach for Critical Sociology of Contemporary Communication Technology
(Sage Publications inc, 2024) Arda, Balca
Critical theory has already marked that technology often threatens civil liberties, personal autonomy, and rights. Heidegger, later Marcuse, emphasized how technology is not value-free in its own revealing power of the surrounding environment, external and inner nature. Throughout this paper, I explore how the aesthetic approach engages with critical theory and contributes to the sociology of media and communication. For this, I will theoretically survey the terms of sociality under the forces of immediate communication, ubiquitous surveillance, and the compression of time and space that Baudrillard and Virilio once problematized through the lens of critical technology theory to adapt it to media and communication studies. I contend that techno-aesthetics that converge with Ranciere's dissensus can provide practical suggestions on an updated vocation of critical sociology. This article discusses the potential of aesthetic and social criticism of media for democratizing technology that Feenberg inserted. It is urgent to acknowledge the changing spatio-temporal aesthetic regimes that affect the societal imagination and limits of sociality and action to determine the next steps for achieving a commons-based society.
Citation - WoS: 4
Citation - Scopus: 6
Agent-Based Optimization To Estimate Nash Equilibrium in Power Markets
(Taylor & Francis Inc, 2013) Yücekaya, Ahmet; Valenzuela, Jorge
In most deregulated power markets firms bid daily into a day-ahead power market. The auction mechanism supply and demand determine the equilibrium at each hour. In this environment firms aim to maximize their revenues by carefully determining their bids. This requires the development of effective computational methods that help them estimate their competitors' behaviors under incomplete information. In this article an agent-based method that uses particle swarm optimization is described to simulate the behavior of market participants. Particle swarm optimization is used in the bidding process and an agent-based model is applied to find a Nash equilibrium. Different stopping conditions are used to determine the equilibrium. Experimental results are presented for two power systems.
Alienation and Hedonic Values in Mass Tourism
(Routledge Journals, Taylor & Francis LTD, 2025) Golcheshmeh, Sueheyla; Kozak, Metin
This study aims to reveal (1) the alienation of tourists, (2) whether locals experience alienation or not, and (3) the kind of relationship between alienation, hedonic consumption and hedonic wellbeing. The study employed a qualitative research method on two samples of locals and domestic tourists. Study findings demonstrate that locals' deprivation of hedonic consumption and alienation may negatively affect their hedonic wellbeing. Tourists may experience alienation because they hardly meet their hedonic consumption needs. The study contributes to the gap in the current tourism literature dealing with alienation, which tourists and residents can experience. The study also develops an understanding of the approaches to the subjects of tourist motivations, attitudes of locals, and impacts of tourism.
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.
Alternative Transducer Power Gain Expression in Broadband Matching Network Designs
(Institute of Electrical and Electronics Engineers Inc., 2017) Sengul, M.
In this paper, a reflection coefficient based transducer power gain expression has been derived, which is an alternative to the impedance based expression exists in the literature. A broadband double matching problem is solved by using the derived gain expression and the obtained performance has been compared with the performance obtained via the existing expression. © 2016 The Chamber of Turkish Electrical Engineers.
Analysis and Implications of the Giant Component for an Online Interactive Platform
(Int Business Information Management Assoc-IBIMA, 2016) Aydın, Mehmet Nafiz; Perdahci, N. Ziya
This research is concerned with practical and research challenges related to understanding the nature of online interactive platforms. So-called network science is adopted to investigate the very nature of these systems as complex systems. In this regard we examine an online interactive health network and show that the interactive platform examined exhibits essential structural properties that characterize most real complex networks. We basically look into the largest connected component so-called a giant component (GC) to better understand how the representative network has established. In particular we apply dynamic network analysis to investigate how the GC has evolved over time. We identify a particular pattern towards emerging a GC. Implications of the patterns have been elaborated from a management perspective. We recommend that the basic stages of the emergence of the GC might be of interest to platform managers while evaluating performance of online platforms.
Citation - WoS: 21
Citation - Scopus: 24
Analysis of efficiency and performance of global retail supply chains using integrated fuzzy SWARA and fuzzy EATWOS methods
(Springer, 2022) Gorcun, Omer Faruk; Zolfani, Sarfaraz Hashemkhani; Canakcioglu, Mustafa
The current paper aims to fill the two severe and significant gaps in the literature related to global retail chains. First, it presents the criteria set identified by performing comprehensive fieldwork together with experts highly experienced and have extensive knowledge of the retailing industry and a detailed literature review. Secondly, it proposes a robust, applicable, and powerful novel integrated MCDM framework dealing with many complicated uncertainties. As one of the significant practical and managerial implications, the current paper highlights the significance of sustainable retailing operations to better global retail chains. After the proposed model was implemented, a comprehensive sensitivity analysis was performed to test the validation of the model and its obtained results. According to the validation test results, A12 Walmart&ASDA has remained the best option for all scenarios. It has been observed that there are slight changes that did not change the overall results in the ranking performance of some decision alternatives. As a result, the analysis results prove that the proposed integrated fuzzy approach can be applied to solve highly complex decision-making problems encountered in various fields and the retailing industry.
Citation - WoS: 7
Citation - Scopus: 12
An Analysis of Price Spikes and Deviations in the Deregulated Turkish Power Market
(Elsevier, 2019) Gayretli, Gizem; Yücekaya, Ahmet; Bilge, Ayşe Hümeyra
The successful operation of a real time market is related to the planning in the day ahead market. We analyze the day ahead and real time market data for the Turkish power market for the period 2012-2015 to classify price spikes and their causes. We also focus on the levels of deviation between the day ahead market values and the real time market values. We define price deviation and load deviation ratios to measure the level of deviation both in price and demand. The analysis for the load is based on load shedding and cycling values. We analyze the mean and standard deviation in market prices and we determine the price spike as a two sigma deviation from the mean value. It is shown that 60% of the price deviation ratios are in the range of ( +/- 20%), while 44% are in the range of ( +/- 10%) and 35% are in the range of (+/- 5%). We also show that 56.9% of the spikes are due to problems in the generation of natural gas based power plants which affect the day ahead and real time prices. A total of 29.2% of the spikes are due to power plant and system failures that affect only real time prices. The share of high temperature based spikes is 13.9% which is a result of air conditioner usage.
Citation - Scopus: 89
An Analytic Network Process-Based Approach To Concept Evaluation in a New Product Development Environment
(Taylor & Francis, 2007) Ayağ, Zeki; Özdemir, Rifat Gürcan
Selecting the best product concept is one of the most critical tasks in a new product development (NPD) environment. Making decisions at this stage becomes very difficult due to imprecise and uncertain product requirements. So the evaluation process of determining the most satisfying conceptual design has been a very vital issue for companies to survive in fast-growing markets for a long time. Therefore most companies have used various methods to successfully carry out this difficult and time-consuming process. Of these methods an analytic hierarchy process (AHP) has been widely used in multiple-criteria decision-making problems (i.e. concept selection equipment evaluation). In this study however we use an analytic network process (ANP) a more general form of AHP due to the fact that AHP cannot accommodate the variety of interactions dependencies and feedback between higher and lower level elements. Briefly in this paper an ANP-based approach is presented to evaluate a set of conceptual design alternatives in order to reach to the best concept satisfying the needs and expectations of both customers and company. In addition a numerical example is presented to illustrate the proposed approach.
Analyzing Multiple Pricing Decisions for Substitutes Under Stochastic Demand: an Experiment
(John Wiley & Sons Ltd, 2022) Ayvaz-Cavdaroglu, Nur; Buyukboyaci, Muruvvet
This study investigates how individuals choose prices for two substitutes under stochastic demand in an airline setting. We design two treatments: symmetrical and asymmetrical, meaning the demand distribution of the two flights having the same size of support or not. Several insights are obtained. First, the decision makers' price choices are closer to the theoretical benchmarks in the symmetrical setting. Next, the subjects do not want to overprice and fly with empty seats, exhibiting loss aversion with reference point. Finally, the subjects often treat the flights as independent rather than interrelated and price them separately, using an anchoring-and-adjusting heuristic.
Citation - WoS: 7
Citation - Scopus: 7
Anytime. Everywhere. Mobile Learning in Higher Education: Creating a Gis Course
(Springer-Verlag Berlin, 2012) Erkollar, Alptekin; Oberer, Birgit
The course concepts introduced in this contribution were implemented in 2011 in a university in Turkey and show an approach for integrating mobile learning modules in higher education. The results of the course show the advantages as well as potential for improvement of the system and the use of it in higher education.

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