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- MakaleYalnız künye2023Scopus SJRQ2COVID-19 Vaccine Acceptance, Trust in Vaccine, Anxiety Levels, and Related Factors in Turkish Society
Aydln, Merve; Kulakaç, Nurşen; Uzun Şahin, Ceyda
Background: Vaccine acceptance and trust in vaccines pose a complex process affected by many factors. The present study was conducted to determine coronavirus disease 2019 (COVID-19) vaccine acceptance, trust in vaccines, anxiety levels, and related factors in Turkish society. Methods: The data of this cross-sectional and descriptive-correlational study were collected with the snowball method by using an online questionnaire throughout Turkey. The study was conducted between March 15 and April 3, 2021, with 3148 participants from 7 regions and 81 cities in Turkey. Results: It was found that the participants accepted the vaccine at 72.8%, and the trust rate in the vaccine was 66.0%. It was also found that women, single participants, those who had immune system diseases, and with COVID-19 had higher Coronavirus Anxiety Scale scores at significant levels. According to Logistic Regression Analysis, gender, age, trust in the vaccine, perception of risk levels regarding COVID-19, and coronavirus anxiety levels are factors affecting the intentions of participants to accept/reject the vaccine. It was determined that male participants were more likely to accept the coronavirus vaccine (P = 0.028). It was found that health-care employees had higher trust in the coronavirus vaccine (P = 0.006) and acceptance rates (P = 0.010) at significant levels compared with the general population. Conclusion: The COVID-19 vaccine acceptance rate in Turkish society was found to be high, and the level of trust in vaccines and anxiety levels were above the moderate level.
AtıfScopus1WoS1OpenAlex1
İncele - MakaleAçık Erişim2022Scopus SJRQ3The Determinants of Immigrants’ Skill Composition
Karapınar Kocağ, Esra; Li, Yutong; Popescu, Cristina Raluca Gh.
Movements of labor across the world is an ongoing debate in the literature in terms of its drivers and results in sending and receiving areas. Skill composition of immigrant labor has been discussed by several papers, although they generally focused on visa policies or firm level productivity. However, this paper focuses on the relationship between immigrants’ educational attainment and government budgeting on research and development (R&D). Panel data analysis is applied for European countries, along with instrumental variable approach as a robustness check. Findings reveal that higher budget allocation for R&D is associated with higher skill level of immigrants within overall immigrant population. This finding is driven by young immigrants whose ages are between 25 and 34 and female immigrants in these countries, suggesting that this relationship varies among sub-groups of immigrants, which would have significant policy implications. Hence, the novel and original approach of the paper resides in the deciding factors of immigrants’ skill composition.
AtıfScopus1İncele - MakaleYalnız künye2023Scopus SJRQ3Gyroscopic suspension for a heavy vehicle
Ünker, Faruk
In this study, an angular momentum generated by a flywheel gyroscope is performed as a suspension to prevent vehicle vibration. The frequency equations are derived and the optimal flywheel speed is obtained for vibration attenuation of the sprung mass. It is observed that the control moment gyroscope (CMG) keeps the sprung mass in the upright position with a small vibration amplitude of a steady motion. The flywheel speed (Ω) is in relation to the amplitude of gimbal motion and the frequency (ω) of the axle’s excitation. Besides, a simulation model of CAE software (RecurDyn) is built to validate the equations of motion.
AtıfScopus6WoS4İncele - MakaleYalnız künye2023Scopus SJRQ3The effect of the Y2O3 buffer layer on the microstructural and physical properties of melt-processed Y358 superconductor
Başoğlu, Mehmet; Çakir, Bakiye; Duman, Şeyda; Aydiner, Alev
The Y3Ba5Cu8O18 (Y358) superconductors were produced using the Melt-Powder-Melt-Growth (MPMG) method. In the crystal growth process, Y2O3 powder was used as a substrate in both powder and tablet form. The first sample was produced without using any buffer layer, the second sample was produced with a powdered Y2O3 buffer layer, and the third sample was produced with a tablet-form Y2O3 buffer layer. The effect of the Y2O3 substrate on the structural and physical properties of the Y358 superconductor samples was investigated. Superconducting phases were observed in all samples of Y358 through XRD measurements, confirming their presence. Samples fabricated using the powder and tablet forms of the Y2O3 substrate had a better microstructure than the sample fabricated without a Y2O3 substrate. The highest critical current density (J c) value was obtained at 77 K for the Y358 sample produced with a Y2O3 powder substrate, and the J c value was calculated as 1.2 × 104 A cm–2 according to the Bean model.
AtıfScopus1WoS1OpenAlex1İncele - MakaleYalnız künye2024Scopus SJRQ3Adsorption of Azocarmine G dye on H2SO4-modified acacia sawdust
Duran, Celal; Ozeken, Sengul Tugba; Camoglu, Aslihan Yilmaz; Ozdes, Duygu
Presence of hazardous dyes in water cause considerable risks to the human health and environment due to their potential toxicity and ecological disruptions. Therefore, in the present research, to suggest an alternative method for the retention of toxic Azocarmine G (ACG) dye from aqueous media, natural and H2SO4-modified acacia sawdust were performed for the first time as low-cost and efficient adsorbents. Based on batch experiments, it was determined that the best conditions for the developed dye retention process were an initial pH of 2.0 and an equilibrium time of 240 min. Analysis of the data using both pseudo-first order and pseudo-second order kinetic models showed that the retention of ACG onto the adsorbents predominantly occurred through chemical adsorption. Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models were employed to provide insights into the interaction between the adsorbate and adsorbent and the mechanism of the adsorption process. Maximum monolayer adsorption capacities of natural and H2SO4-modified acacia sawdust were determined as 28.01 and 64.90 mg g-1, respectively by Langmuir isotherm model. Results of the study clearly indicated that the modification of acacia sawdust with H2SO4 leads to a substantial increase in the adsorption performance of anionic dyes.
- MakaleYalnız künye2022Scopus SJRQ2The two-way perspective of tourism undergraduates towards (post-)viral world: The future of tourism, and vocational development and career
Seyitoğlu, Faruk; Atsız, Ozan; Kaya, Fazıl; Taş, Sedat
This timely paper explores the future of tourism and vocational career in the Covid-19 period from the perspective of undergraduate tourism students. The data were collected through semi-structured interviews with 30 students majoring in tourism faculty departments following the qualitative methodology. The findings demonstrate that vocational development and career planning in the Covid-19 era and the future of tourism are the main dimensions identifying students’ perspectives. The vocational and psychological pandemic effects are shaping the future career decisions of students. Furthermore, the future of tourism includes the elements related to tourist expectations and behaviours and trends in the (post-)viral tourism.
AtıfScopus23WoS16OpenAlex25İncele - MakaleAçık Erişim2024Scopus SJRQ4A driver perspective-based investigation for lane line visibility of pavements on drivers’ lane utilization behaviors
Aydın, Metin Mutlu; Orhan, Eda
There have been significant advances in vehicle safety and road construction in all over the world and driver misbehaviours are still shown as one of the most important reasons of traffic accidents. When the current traffic accidents are examined, the negative effect of lane line quality and level of visibility related on the accidents comes to the forefront in underdeveloped and developing countries. In this study, the effect of lane line visibility level on drivers' lane utilization was investigated in detail. For this aim, a total of 17 different points in Türkiye were selected and the lateral positions of the vehicles on the road surface at these points were determined with the help of the screen scaling technique. In order to determine the level of lane line quality for an expert group and driver perspective, a face-to-face survey was conducted. From the analysis results, the lane line quality was determined low in urban and intercity roads, and the average maximum evaluation score was determined as 4.7 and the lowest score was determined as 1.42 where the best line quality was 5. This result showed that the level of lane line quality had significant differences at different points. Although, it was observed that the lateral position distributions in the examined points fit the normal distribution, the distribution of both the right/left wheels and their gravity center skewed to the right or left and deviated from the ideal conditions on road surfaces. It showed that the vehicles do not center the lanes exactly, but usually move close to the right or left edge of the lane. This situation also clearly revealed that the lane utilization disciplines of drivers are quite weak with the effect of the low lane line quality on road surfaces.
- MakaleYalnız künye2024Scopus SJRQ1Investigation of dynamic responses of three-sided underpass culvert under near-fault and far-fault ground motions considering soil-structure interaction
Ozturk, Kasif Furkan
Three-sided underpass culverts are structural systems used to provide passing vehicle or pedestrian. It is of great importance that such infrastructure systems remain useable, especially after disasters such as earthquakes that can cause great destruction, in order to ensure that infrastructure services can be maintained continuously. In this context, the aim of this study is to investigate using finite element method (FEM) the dynamic responses of three-sided underpass culvert system under near-fault ground motions with velocity pulse and far-fault ground motions. For this aim, the modal analysis of the soil-underpass culvert interaction system has been realized using proposed soil-structure interaction (SSI) model. The frequencies of the interaction system obtained from the finite element model developed using proposed approaches have been verified comparing with the results obtained from the literature and the site periods. After showing that the modes of the interaction system can be obtained with the help of the proposed numerical model, the full transient dynamic analyses have been performed in the time history using five near-fault and far-fault records, considering four different soil systems. The comparisons shows that the variations of the soil systems and the ground motion type can significantly affect the top peak relative displacements and the dynamic stresses of the three-sided underpass culvert.
AtıfScopus16WoS13OpenAlex15İncele - MakaleAçık Erişim2024Scopus SJRQ1Integrated deep learning and ensemble learning model for deep feature-based wheat disease detection
Catal Reis, Hatice; Turk, Veysel
Early detection of plant diseases is critical to prevent disease spread and assist farmers. Thanks to their high discrimination ability, Convolutional Neural Network (CNN)-based architectures can offer practical solutions in identifying different plant diseases. This study proposes a combined method to classify wheat plant diseases using the Integrated Deep Learning Framework (IDLF) and ensemble learning (EL) model. The proposed method uses pre-trained deep neural networks (ImageNet -based model (w/pre-training)). In addition, in the classification process, the performance of hybrid methods consisting of 13 deep learning architectures (DLA) trained from scratch, pre-trained DLA, deep, and-machine learning models were analyzed. Moreover, the use of hypercolumn, contrast stretching, and “Contrast Limited Adaptive Histogram Equalization (CLAHE)” techniques are used to improve the image quality of the dataset. It is aimed to obtain a strong classification performance by combining these methods. In the experimental process, in the study using the original dataset, the RegNetY080 model trained from scratch had an accuracy value of 97.64%; in the study with the optimized dataset with CLAHE, an accuracy value of 98.33%; in the study performed with the CLAHE-improved dataset and transfer learning method, an accuracy value of 99.58% was obtained. An accuracy of 99.58% was achieved in the proposed hybrid study with the pre-trained RegNetY080 model and Random Forest (RF). The proposed method using IDLF and EL model provided 99.72% accuracy. When the proposed method was applied to the Wheat Leaf Dataset and Wheat Leaf Disease dataset, 97.56% accuracy was obtained for the Wheat Leaf Dataset and 99.43% for Wheat Leaf Disease. The results of this study can be helpful to experts and farmers in the detection of plant diseases.
AtıfScopus49WoS33OpenAlex41İncele - MakaleAçık Erişim2023Scopus SJRQ3New epiphytic bryophyte communities from Turkey; [Nove zajednice epifitskih briofita iz Turske]
Alataş, Mevlüt; Erata, Hüseyin; Batan, Nevzat; Ezer, Tülay
The epiphytic bryophyte vegetation of the Kümbet Plateau (Dereli-Giresun) was investigated. A total of 40 relevés taken from tree trunks in different vegetation periods of the year 2019 were analysed using multivariate analysis methods such as detrended correspondence analysis (DECORANA) and two-way indicator species analysis (TWINSPAN), and the Braun-Blanquet method was also applied. As a result, Frullanio tamarisci-Neckeretum pumilae Alataş, Ezer, Batan & Erata ass. nov. and Frullanio tamarisci-Neckeretum pumilae-isothecietosum alopecuroidis Alataş, Ezer, Batan & Erata subass. nov. were described as new syntaxa from Turkey. In addition, Ulotetum crispae -sanionietosum uncinatae was recorded for the first time from Turkey, while Ulotetum crispae was recorded for the second time from Turkey. These syntaxa were analysed in terms of their ecological and floristic aspects.
AtıfScopus1WoS1OpenAlex1İncele - MakaleYalnız künye2023Scopus SJRQ1Investigation of used PCM-integrated into building exterior walls for energy savings and optimization of PCM melting temperatures
Terhan, Meryem; Ilgar, Gamze
In the study, the effects on the building's thermal energy performance of using two different phase change materials (PCMs) integrated into the exterior walls at various thicknesses and melting temperatures have been investigated. Four exterior wall types have been designed by changing the position of PCM integrated into the exterior wall for the purpose to decrease heating and cooling energy demand. For each wall type, three different thicknesses (layers) have been studied and energy savings that PCM provided by decreasing the heating and cooling energy demands have been calculated on a monthly and annual basis. According to the energy simulation analyses, the configuration provided the highest heating energy savings (21.32 %) on an annual basis is the three-layer BioPCM27 integrated exterior wall with a melting temperature of 21 °C. The monthly optimum melting temperatures of PCMs have been determined based on the charge and discharge processes of PCM integrated into the exterior walls by evaluating the results of hourly energy simulation analysis. The annual average optimum melting temperature varies between 18 and 19 °C, depending on the exterior wall and material types. The three-layer (3L) InfiniteRPCM21C configuration (Type 3) has the best thermal energy performance among all exterior wall types, with 24.45 % total energy savings in the cooling season and 14.76 % in the heating season.
AtıfScopus71WoS64OpenAlex73İncele - MakaleAçık Erişim2023Scopus SJRQ4Solutions of multiplicative linear differential equations via the multiplicative power series method
Yalcin, Numan; Dedeturk, Mutlu
In this study, fundamental concepts of multiplicative analysis is given. Also, definitions of multiplicative Taylor series (MTS), multiplicative Taylor polynomials (MTP), and multiplicative power series (MPS) are given. Solutions of higher-order multiplicative linear differential equations (MLDE) are investigated with the help of the MPS method. Applications of MPS method are done for first, second, and third-order multiplicative ordinary linear differential equations. Copyright 2021, Yıldız Technical University.
AtıfScopus5WoS5OpenAlex8İncele - MakaleYalnız künye2023Scopus SJRQ1Unpacking the power of user-generated videos in hospitality and tourism: a systematic literature review and future direction
Polat, Eray; Çelik, Fatih; Ibrahim, Blend; Köseoglu, Mehmet Ali
We review user-generated video (UGV)-research in hospitality and tourism (H&T), provide an overview of its current-state, and suggest ways forward. We adopted a systematic literature review methodology and reviewed 66 articles with TCM (theory/context/methodology) framework. UGV-research focuses on (i) destination image perception, (ii) short-form videos and travel live-streaming, (iii) behavioral intentions, and (iv) crisis management. Theoretical development is diverse, given the descriptive nature of research questions, but it is still in its infancy. The context varies by H&T setting, type of social media platform, population, and country. Research methods and techniques range from traditional analysis to advanced machine learning or artificial intelligence-based quantitative approaches, predominantly qualitative methods.
AtıfScopus61WoS43OpenAlex55İncele - MakaleAçık Erişim2022Scopus SJRQ3Women Entrepreneurs' Education Level, Political Skill, and Firm Performance: Political Influence and Human Capital Theories
Demirbaǧ, Orkun; Demirbaǧ, Kübra Simşek; Batl, Gülgönül Bozoǧlu
Purpose: Because of the growing interest in the literature in education and political skill as facilitators of firm performance, this article aims to reveal whether there is a moderating role of women entrepreneurs' political skill on the relationship between their education level and firm performance when firm- and entrepreneur-level characteristics remain under control. Methodology: The study was conducted in Istanbul, Kocaeli, and Bursa, cities with the lowest gender gap in Turkey. The participants of the questionnaires were 291 entrepreneurs who are members of the Women Entrepreneurs Association of Turkey (KAGIDER), the Women Entrepreneur Members of Endeavor Turkey, and the TOBB Women Entrepreneurs. Hierarchical regression analysis was performed to analyze the dataset. Findings: When firm- and the entrepreneur-level characteristics remain under control, women entrepreneurs' political skill shows a moderator role in the relationship between women entrepreneurs' education level and firm performance. Practical Implications: A bachelor's degree or higher, along with political skill, allow women entrepreneurs to increase their firm performance. Furthermore, the higher the political skill, the higher the effect of education level on firm performance. Originality/Value: This is the first study to investigate the moderating role of political skill of women entrepreneurs in the relationship between education level and firm performance. Moreover, political influence and human capital theories are jointly applied to the theoretical model.
AtıfScopus4WoS2OpenAlex5İncele - MakaleYalnız künye2024Scopus SJRQ2An efficient Hartley–Ross type estimators of nonsensitive and sensitive variables using robust regression methods in sample surveys
Zaman, Tolga; Shazad, Usman; Yadav, Vinay Kumar
In sample surveys, the problem of outliers is one of the most frequent and widest, whose solution is required to be obtained using statistical techniques. To overcome this problem, various robust regression methods are being developed such as LTS, LMS, LAD, Huber-M, Hample-M, Tukey-M and Huber-MM methods. This article presents the modified Hartley–Ross type ratio estimators to estimate the population mean in sample surveys. The proposed design is taken into account under the two suppositions one is that the study variable is a non-sensitive variable, which means that measurements on it do not embarrass participants in personal interviews and other is the sensitive variable, which means that measurement errors are introduced as a result of a few dishonest responses. The use of scrambling response models helps to reduce these measurement errors to some extent. The proposed estimator is found to be more efficient than the existing classical estimators. A Numerical illustration was performed on a real data set in R-Program Software to support of our findings.
AtıfScopus15WoS17OpenAlex16İncele - MakaleAçık Erişim2022Scopus SJRQ2The relationships between institutionalization and dual commitment: A study on hotel kitchen employees
Evren, Emine Şimşek; Celil Çakıcı, A.
Long-termed continuance of employees in hotel enterprises, especially in kitchen department where standard production is of utmost importance, is critical for organizational success. At this point, how institutionalization, a phenomenon that is usually associated with standardization, effects the organizational commitment (OC) is an important question. Another important question is how commitment to an impressive supervisor such as the chef mediates the relationship between institutionalization and OC in institutionalized hotels where standards become important instead of personal approaches. In this context, the relationship between institutionalization, OC, and commitment to the supervisor (CS), which has not been studied before, has been examined within the framework of hotel businesses. The data were collected with an online survey. The sample consisted of the kitchen staff of a national hotel chain in Turkey. The findings demonstrated that the effects of institutionalization on OC and CS were significant. CS partially mediates the relationship between institutionalization and OC. When considered within the scope of the dimensions, the CS has a partial mediating effect on the relationship between cultural power and all three dimensions of OC (affective, continuance, normative). The effect of formalization and professionalization on affective and normative commitment is partially mediated by CS.
AtıfScopus1OpenAlex2İncele - MakaleYalnız künye2023Scopus SJRQ1A Proposed V2V Path Loss Model: Log-Ray
Kuzulugil, Kenan; Tugcu, Zeynep Hasirci; Cavdar, Ismail Hakki
Vehicle-to-vehicle (V2V) communication that has prominent involvement in the design of innovative communication solutions for the intelligent transportation system. Therefore, to develop V2V channel models, the knowledge of the propagation channel on which comprehensive research efforts have been carried is vital. In this study, we focused on the analysis and modeling of path loss characteristics for V2V communications and proposed a log-ray path loss model with the motivation of overcoming remarkable fitting errors between the two-ray model and measured data where the path loss exponent corresponds to different from 2. First, channel measurements were performed at 5.9 GHz with commercially available DSRC OBU devices for five different scenarios in typical highway and suburban environments in Gümüşhane, Turkey. Then, the large-scale characteristics of different propagation scenarios were analyzed and the proposed log-ray model performance was compared with commonly used log-distance and two-ray path loss models qualitatively and quantitatively. On the other hand, analysis of small-scale modeling and shadowing were also conducted for all scenarios and presented in the results. The findings clearly demonstrate that the proposed log-ray path loss model fits the measured data with a smaller RMSE value (2.54 dB) than the results of the log-distance (3.07 dB) and two-ray (3.72 dB) path loss models in the literature. In other words, the proposed model has approximately 17.5% and 32% increase in fitting performance according to the log-distance and the two-ray path loss models, respectively. The study results will be helpful for better performance analysis and system design of V2V communication.
AtıfScopus13WoS11OpenAlex12İncele - MakaleYalnız künye2023Scopus SJRQ1Effect of foundation embedment ratio in suppressing seismic-induced vibrations using optimum tuned mass damper
Araz, Onur; Cakir, Tufan; Ozturk, Kasif Furkan; Kaya, Dilek
Tuned mass damper (TMD), which is used in structures to mitigate the dynamic responses caused by environmental loads, is tuned according to the dominant frequency of the structures. The dominant frequency of structure built on soil with low stiffness is significantly affected by the soil-structure interaction (SSI). In previous studies, only the surface foundation case is considered to investigate the design parameters of TMD considering SSI effects and the embedment depth of the foundation is neglected in these studies. Thus, this paper investigates the optimization of TMD for mitigation of responses of a high-rise building considering various depths of embedment and soil properties. The optimum parameters of TMD are investigated using five different optimization algorithms (i.e., simulated annealing, sequential quadratic programming, genetic algorithm, pattern search, and particle swarm optimization). The objective function minimizes the peak acceleration amplitude at the top of the structure. The effectiveness of optimum TMD is verified to use 20 near-fault pulse-like ground motions. The comparisons show that the embedment ratio of the foundation and the soil properties significantly affect the optimization of TMD.
AtıfScopus28WoS26OpenAlex27İncele - MakaleAçık Erişim2023Financial Wellbeing during Covid-19 Pandemic: Concerns about Medical Costs; [Covid-19 Salgını Sırasında Finansal Refah: Tıbbi Maliyetlerle İlgili Endişeler]
Kocağ, Esra Karapinar
Financial wellbeing which represents a great concern for individuals regardless of their social status or their current employment situation constitutes an important element of overall individual wellbeing. Within a broader structure of financial wellbeing, concerns about medical costs have gained a vital importance particularly following the pandemic. Identifying what factors influence this growing concern is critical to tackle with the problem and improve individual wellbeing. Hence, this study is expected to shed light on such an important individual and national concern. To that end, this paper utilizes Global Financial Inclusion Database which is based on national representative surveys of about 128,000 adults across more than 120 countries. Empirical analysis in which ordered probit model was applied aims to investigate if there exists an association between financial concerns about medical costs and COVID-19. Findings of the empirical investigation reveal that being in the group of those who are very worried about financial hardship due to Covid-19 outbreak increases the probability of reporting being very worried about medical cost payments by about 34.5 percentage points. Therefore, it is seen that pandemic detrimentally related to individuals’ increased concerns over medical costs. These findings are expected to guide policy makers on the management of healthcare system and measures to improve individual wellbeing.
AtıfOpenAlex1İncele - BildiriYalnız künye2023Current Sources and Actual PV Modules based Photovoltaic (PV) Emulator for Testing MPPT Algorithms and PV Inverters
Zhou, Zhongfu; Wang, Yidong; Yanarates, Cagfer; MacAulay, John
PV array emulator has been widely used for testing PV inverters and their control algorithms such as maximum power point tracking (MPPT) algorithms. Various power electronics converter-based PV emulators have been presented in many research papers. This paper presents a PV emulator that is based on indoor solar panels (without solar irradiance) and external current source (dc power supply). The external current source is used to emulate the photo current that is usually generated by solar panel under sunlight. The advantages of the proposed PV emulator are that it can generate similar electrical characteristics of actual PV panel without sunlight, it is suitable for testing PV inverters and MPPT algorithms in indoor conditions where the sunlight is usually very weak. In addition, a PV array emulator that can emulate electrical performance under partial shading conditions was constructed by using two solar panels and two current sources. Test results show that the proposed PV emulator provides a similar performance of real PV array under real sun light. It provides a low-cost solution for testing PV inverters and control algorithms inside a laboratory environment.
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