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Koleksiyondaki öğeler
- MakaleYalnız künye2019Scopus SJRQ2Combined active flow and flight control systems design for morphing unmanned aerial vehicles
Kanat, Öztürk Özdemir; Karatay, Ertuğrul; Köse, Oğuz; Oktay, Tuğrul
In this article, combined active flow control system and flight control system design for morphing unmanned aerial vehicles is applied for the first time for autonomous flight performance maximization. For this purpose, longitudinal and lateral dynamics modeling of morphing unmanned aerial vehicle having active flow control manufactured in Erciyes University, Faculty of Aeronautics and Astronautics, Model Aircraft Laboratory is considered in order to obtain simulation environments. Our produced morphing unmanned aerial vehicle is called as ZANKA-II, which has a mass of 6.5 kg, range of 30 km, endurance of 0.5 h, and ceiling altitude of 6000 m. von Karman turbulence modeling is used in order to model atmospheric turbulence during flight in both longitudinal and lateral simulation environments. A stochastic optimization method called as simultaneous perturbation stochastic approximation is also applied for the first time in order to obtain optimum dimensions of morphing parameters (i.e. extension ratios of wingspan and tail span), optimum positions of blowers, and optimum magnitudes of longitudinal and lateral controllers' gains (i.e. P, I, and D gains) while minimizing cost index capturing terms for both longitudinal and lateral autonomous flight performances and there exist lower and upper constraints on all optimization variables in the literature.
AtıfScopus17WoS14OpenAlex15
İncele - MakaleAçık Erişim2022Scopus SJRQ1Performance evaluation of privatized ports by entropy based TOPSIS and ARAS approach
Gök-Kısa, A. Cansu; Çeli̇k, Pelin; Peker, İskender
Purpose: Ports are the key elements of maritime transportation, which is crucial for world trade. Approximately 180 port facilities are located in Turkey. After 2007, 5 of the ports, which are formerly owned by Turkish Republic Railways Administration (TRRA), are privatized. The aim of the study is to evaluate the performance of these privatized ports by multi-criteria decision-making (MCDM) approach. Design/methodology/approach: The application process is performed by a MCDM model. This model includes both criteria (dry bulk, liquid bulk, general cargo, container, RO-RO capacity, total port area, total berth, total berths length and depth) and alternatives (Mersin, Samsun, Bandirma, Iskenderun and Derince Ports). It determines the weights of the criteria by entropy and ranks the alternatives by ARAS and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) methods. Findings: The results of entropy, ARAS and TOPSIS methods are compared. According to these results, “container” is the most important criteria while Mersin port has the best performance. Originality/value: In the literature, most of the studies about this subject were analyzed by data envelopment analysis (DEA) and there are no studies had been taken into consideration ports that are owned by TRRA, in Turkey. Moreover, few of these studies used integrated MCDM models, and this is the first study that integrates entropy, ARAS and TOPSIS methods in this field.
AtıfScopus27WoS25İncele - MakaleYalnız künye2020Scopus SJRQ2The Effect of Laughter Therapy on Anxiety: A Meta-Analysis
Demir Doǧan, Melike
This meta-Analysis was conducted to determine the effect of laughter therapy on anxiety. Randomized controlled clinical trials were reviewed on Google Scholar, PubMed, and ISI Web of Sciences databases. Four randomized controlled trials consisting of 157 participants were included in the meta-Analysis. Hedge's g test statistics were used to show the common effect between the laughter therapy and control groups in the meta-Analysis. Laughter therapy can decrease anxiety levels (standardized mean difference =-1.144; 95% CI,-1.950 to-0.338). Laughter therapy is an effective complementary method to decrease anxiety.
AtıfScopus38WoS30OpenAlex63
İncele - MakaleAçık Erişim2020Scopus SJRQ3Tuned gyro-pendulum stabilizer for control of vibrations in structures
Ünker, Faruk
A special combined gyro-pendulum stabilizer (a gyroscope with coupling to a pendulum) mounted on a vibrating mass is considered for investigation of the vibration responses. This paper mainly focuses on the derivation of the frequency equations and on finding the required angular momentum for vibration control of the system. Besides, there is also an ANSYS simulation model of gyro-pendulum, which was built to verify the mathematical model. The dynamic responses of both that obtained from ANSYS simulation and that obtained from numerical solving of a Lagrangian mathematical model are analyzed comparatively. The angular momentum (ΩIp), in relation to the natural frequency (ωn) of the primary mass, shows that this vibration control device is more adaptable than other conventional ones by producing unidirectional thrust along the forcing excitation axis whilst the gyroscope is spinning.
AtıfScopus9WoS5OpenAlex10İncele - MakaleAçık Erişim2021The Effects of Economic Recessions on Divorce Rates: A Research on Turkey; [Ekonomik Resesyonların Boşanma Oranları Üzerindeki Etkileri: Türkiye Üzerine Bir Araştırma]
Koç, Pınar; Kutlar, Aziz
This study analyses the relationship between short-and long-term relationships between divorce rates and economic recession in Turkey. The asymmetric and time-varying asymmetric causality tests are used to analyse the short-term relationship, the Maki cointegration test is used to analyse the long-term relationship. The dependent variable of the model is the divorce rate. Labour force participation rate of women, unemployment rate, GDP per capita, legal regulations, and economic crises are independent variables. According to the estimation results, unemployment, national income, legal regulations, and economic crises positively affect divorce rates. The time-ric causality test results also indicate a temporary causality relationship between positive income and unemployment shocks.
AtıfScopus2WoS4OpenAlex4TR Dizin3
İncele - MakaleYalnız künye2022Scopus SJRQ2Detection of damaged buildings after an earthquake with convolutional neural networks in conjunction with image segmentation
Ünlü, Ramazan; Kiriş, Recep
Detecting damaged buildings after an earthquake as quickly as possible is important for emergency teams to reach these buildings and save the lives of many people. Today, damaged buildings after the earthquake are carried out by the survivors contacting the authorities or using some air vehicles such as helicopters. In this study, AI-based systems were tested to detect damaged or destroyed buildings by integrating into street camera systems after unexpected disasters. For this purpose, we have used VGG-16, VGG-19, and NASNet convolutional neural network models which are often used for image recognition problems in the literature to detect damaged buildings. In order to effectively implement these models, we have first segmented all the images with the K-means clustering algorithm. Thereafter, for the first phase of this study, segmented images labeled “damaged buildings” and “normal” were classified and the VGG-19 model was the most successful model with a 90% accuracy in the test set. Besides, as the second phase of the study, we have created a multiclass classification problem by labeling segmented images as “damaged buildings,” “less damaged buildings,” and “normal.” The same three architectures are used to achieve the most accurate classification results on the test set. VGG-19 and VGG-16, and NASNet have achieved considerable success in the test set with about 70%, 67%, and 62% accuracy, respectively.
AtıfScopus22WoS14OpenAlex25İncele - MakaleAçık Erişim2020Scopus SJRQ3Effects of lactobacillus reuteri e81 added into rations of chukar partridges (Alectoris chukar) fed under heat stress conditions on fattening performance and meat quality
Tekce, Emre; Bayraktar, B.; Aksakal, V.; Dertli, E.; Kamiloğlu, A.; Çinar, K.; Takma, Ç.; Kaya, H.; Gül, M.
This study investigated the effects of the addition of Lactobacillus reuteri E81 (LRE) into rations of chukar partridges (Alectoris chukar) fed under heat stress (HS) conditions on fattening performance and meat quality. This study included 256 chukar partridges aged 1 day. The study comprised an adaptation period of 7 days and a fattening period of 35 days and included 8 different groups with 32 animals in each group. Each group was further divided into four subgroups with eight animals in each subgroup. At the end of the study, the best results in terms of fattening performance in the non-HS groups were obtained in the LRE 600 ppm group and in the HS groups, SLRE 200 ppm had the best effect on average live weight and average live weight increase, whereas SLRE 400 ppm had the best effect on FCR (p<0.05). The analysis of the samples collected from chukar partridges on day 21 showed that, there was no effect on the colour parameters and Thiobarbituric acid reactive substances (TBARS) level in the LRE in the HS and non-HS groups, whereas the meat pH level decreased in the SLRE 400 ppm group (p<0.05). The analysis of the samples collected on day 42 showed that there was no effect on colour parameters in the HS and non-HS groups. TBARS level decreased at the dose of LRE 200 ppm in the non-HS group, and the meat pH level decreased in both HS and non-HS groups (p<0.05).
AtıfScopus2WoS2OpenAlex7İncele - MakaleAçık Erişim2022The effect of tourism and legalization policies on summer pasture in Turkey
Döner, Fatih
In Turkey, according to Pasture Law, land allocated for farmers to spend the summer with their animals, graze their animals and benefit from grass is defined as “summer pasture (yaylak in Turkish).” Summer pasture is of national importance for its biodiversity, landscape, cultural heritage and transhumance. However, especially after 1990s, the summer pasture areas have been extensively used in tourism activities in Turkey. By changing land use, the increasing tourism activities combined with legal uncertainties and the legalization policies have caused summer pasture areas transferred into built-up areas. The effect of the tourism and legalization policies on the land use changes in summer pasture areas was evaluated in this study. It was determined that Turkey's tourism and legalization policies have adverse effect on sustainable use of summer pasture areas. These policies aimed at economic development and solving property problems of rural areas caused new legal problems and expansion of built-up areas. A better land use policy and an effective control mechanism are necessary for the sustainable use of summer pasture areas.
AtıfScopus3WoS3OpenAlex5TR Dizin1İncele - MakaleAçık Erişim2020Solving for the random component time-fractional partial differential equations with the new Sumudu transform iterative method
Anaç, Halil; Merdan, Mehmet; Kesemen, Tülay
The new Sumudu transform iterative method is implemented to get the approximate solutions of random component time-fractional partial differential equations with Caputo derivative. The parameters and the initial conditions of the random component time-fractional partial differential equations are analyzed with Gamma distribution. The expected values and variances of these solutions are calculated, and the graphs of the expected values and variances are plotted in Maple software. The results for the random component time-fractional partial differential equations with Gamma distribution are examined to investigate effects of this distribution on results. The numerical experiments indicate that this method is very effective.
AtıfScopus12WoS11OpenAlex16İncele - BildiriAçık Erişim2019Numerical solution of Neumann type elliptic overdetermined multipoint mixed boundary value problem
Ashyralyyev, Charyyar; Karabey, Suzan
In the present paper, Neumann type elliptic overdetermined multipoint boundary value problem is discussed. The first and second order of accuracy difference schemes (ADSs) for the numerical solution of elliptic overdetermined multipoint boundary value problems are presented. Stability estimates for solutions of difference schemes are obtained. Numerical results for mixed boundary value problem are given.
- MakaleYalnız künye2021Scopus SJRQ3The role of gender in the government expenditure and unemployment nexus: An investigation at regional level for Turkey
Çelik, Orkun; Erer, Elif
We aim to explore the role of gender in the government expenditure and unemployment nexus at regional level for Turkey. For this aim, we use the dataset covering the period 2004-2019 for 26 NUTS-2 regions in Turkey and employ a panel ARDL approach. The obtained empirical findings show that government expenditure and gross domestic product per capita provide overall, female, and male unemployment rates to diminish in the long term, which means the Keynesian approach is valid on the long term. Nevertheless, on the short term, government expenditure induces rises in the male and female unemployment rates. This result indicates the validation of the Abrams Curve Hypotesis in male and female unemployment rates on the short term. Also, inflation rate increases overall and male unemployment rate on the long term, but having significant and positive impact on only female unemployment rate on the short term. All these findings show that gender has a significant role in this nexus. The expected contribution of this study to literature is to investigate the impact of government expenditure on unemployment by gender at regional level for Turkey. We are of opinion that our empirical findings can guide policy makers in active plans fighting unemployment.
- MakaleYalnız künye2016Scopus SJRQ2The investigation of adhesion and fatigue properties of TiN/TaN multilayer coatings
Baran, Ö.; Sukuroglu, E.E.; Efeoglu, İ.; Totik, Y.
TiN/TaN multilayer coatings exhibit excellent mechanical properties when compared to single layer nitride coatings. In this study, TiN/TaN multilayer coatings were deposited on Mo-alloy and W-alloy substrates by CFUBMS. The structural and mechanical properties of coatings were analysed using XRD, EDS, SEM and a micro-hardness tester, respectively. To determine the adhesion and fatigue behaviour of the coatings were performed a scratch test in two modes that a standard mode with progressive loading and sliding-fatigue multimode operation with unidirectional sliding, respectively. A microscope was used to characterize adhesion and fatigue failures. The structural, mechanical, adhesion and fatigue properties of TiN/TaN multilayer coatings significantly changed depending on the substrate.
AtıfScopus14WoS12OpenAlex13İncele - MakaleYalnız künye2020Scopus SJRQ2Antimicrobial activity of coriandrum sativum L. And its effect on microbiological properties of yoghurt
Gundogdu, E.; Tanriverdi, E.; Yildiz, H.
In this study, the antimicrobial effect of Coriandrum sativum L. leaves against 30 different foodborne microorganisms, including 20 bacteria, 7 fungi, and 3 yeast species was tested, and some microbiological properties of yoghurt produced with lyophilized C. sativum L. were investigated. Yoghurts were prepared at three different concentrations of C. sativum L. powder (0.1, 0.2, and 0.3% w/w) and stored at 4°C for 21 days. Ethanol extract of the fresh plant showed antimicrobial activity against only 9 bacteria and 1 yeast with different inhibition zone diameter changing from 8 to 12 mm, but had no effect on moulds used in this study. The addition of C. sativum L. had no statistical significance on the growth of yoghurt bacteria compared with the control sample and they remained over 8 log CFU g-1 in all yoghurts throught the storage period. On the other hand, an increase was observed in the number of Lactobacillus bulgaricus and a decrease in the number of Streptococcus thermophilus depending on the concentration of C. sativum L., but this was not statistically significant (P> 0.05). However, significant differences in yeast and mould counts were observed (P< 0.05). Yeasts and moulds were not detected in any of the samples containing C. sativum L. powder, whereas the counts of yeast and mould increased in control throught the storage period. These results show that the powder of C. sativum L. leaves can be used an agent for preventing the growth of yeast and mould, which are shelf-life and quality spoilage microorganisms of yoghurt.
AtıfScopus6WoS4İncele - Kitap BölümüYalnız künye2020The economic and fiscal impacts of the Covid-19 pandemic in Turkey and around the world
Şahin, Muhammet
Humanity has a long history of struggle against pandemics. Covid-19 is the most recent example of such kind of pandemics. Since its first outbreak appeared in China on December 31, 2019, the Covid-19 pandemic has spread rapidly across almost all over the globe within a few months. The Covid-19 has been a type of pandemic which requires compliance with social distancing rules, thereby it has caused both demand-side and supply-side slowdown in economic activities. It is estimated that as a result of the pandemics there will be a very sharp economic shrinkage, an increase in unemployment to the highest levels in the history and a significant decrease in global trade. Governments and international organizations have adopted various measures and incentive packages in order to overcome this problem. These packages mainly include monetary and fiscal tools; however, they have the risk of yielding an increase in government debts thus disrupting public fiscal equilibrium. This chapter aims to examine the economic and fiscal impacts of the pandemic and to examine practices both in Turkey and around the world accordingly.
AtıfScopus1İncele - MakaleYalnız künye2020Scopus SJRQ2Prediction of mine drainage generation potential and the prevention method of the groundwater pollution in the Gümüşköy (Kütahya) mineralization area, NW Turkey
Alemdag, Selcuk; Akaryali, Enver; Gücer, Mehmet Ali
One of the leading factors of seepage contamination is mine drainage, which creates serious ecological risks on the environment both during operation and post-mining times. In this study, experimental processes have been carried out to determine the occurrence of mine drainage in the Gümüşköy (Kütahya) mineralization area (Northwest Turkey). The prevention method for potential mine drainage occurrence has been also discussed. High enrichment was observed which are directly related to mineralization in trace element concentrations, especially in potentially toxic metals such as Ag, Cd, Mo, Ba, Bi, and Zn. Based on short-term tests, mine drainage formation has not been expected according to the pH (7.36–9.38), contact leaching, and acid-base accounting studies. However, in the long-term, acid generation potential has been expected because of weathering and oxidation in terms of rock type and mineralization in the area. Therefore, in order to prevent groundwater contamination in the event of a possible formation of mine drainage, the hydraulic conductivity of the stock area bedrock was evaluated by the in situ tests performed in the field and it was found to be moderately permeable (K= 1.9 × 10−6 m/s). In order to make the stock area bedrock impermeable, natural clay will be laid and compressed at the base of the stock area. When the finite elements were modeled by seepage analysis, the seepage discharge to be formed on the base rock at a depth of 5 m was determined as 3.17 × 10−19 m3/s. Since the discharge value determined in the seepage analysis after modeling is very close to zero, contamination of possible ground and surface water will be prevented.
AtıfScopus5WoS3OpenAlex10İncele - MakaleYalnız künye2020Scopus SJRQ2Effect of detuning conditions on the performance of non-traditional tuned mass dampers under external excitation
Araz, Onur
The tuned mass damper (TMD) is a widely used passive control device which is attached to a main system to suppress undesired vibration. In this paper, a non-traditional form of TMD system is investigated. Unlike the traditional TMD configuration, the considered TMD system has a linear viscous damper connecting the absorber mass directly to the ground instead of the main mass. There have been some studies on the optimization design of the non-traditional TMD (NT-TMD) for undamped main structures. Those studies have indicated that the NT-TMD provides better performance than the traditional TMD does. When there is a frequency shifting in the structural frequency or tuning frequency of TMD, to the best knowledge of the authors, there has been no study on the performance of the NT-TMD. The main idea of the study is to investigate the effect of frequency detuning on the control performance of the NT-TMD. The optimum parameters of the NT-TMD system and corresponding effectiveness are obtained for different mass ratios of the NT-TMD system. The numerical results indicate that the NT-TMD with high mass ratio provides better robustness to the changes in the target frequency ratio than the traditional TMD.
AtıfScopus27WoS23OpenAlex27İncele - MakaleYalnız künye2021Scopus SJRQ2The effects of freeze-thaw cycles and block size on the use of the Gümüşhane Granitoid (Gümüşhane/Turkey) as building stone
Dağ, Serhat; Alemdağ, Selçuk; Kaya, Ayberk
The present study aims to examine the usability of the Gümüşhane Granitoid as a building stone taking into consideration the short-term freeze-thaw cycles and mean block volume. A total of 180 specimens were used in the study prepared from the block samples compiled from 10 different areas in the Gümüşhane (NE Turkey) provincial borders. Mean block volume was calculated about 8 dm3 during the discontinuity studies carried out on the Gümüşhane Granitoid; as a result of which, it was determined that the granitoids are suited for obtaining blocks. The annual freeze-thaw cycle map of Turkey was used for determining the number of freeze-thaw cycles to be applied on the rocks in addition to taking into account the weathering of monzogranites. A total of 25 freeze-thaw cycle tests were applied on the rocks with experimental studies repeated at every 5 cycles. It was determined following the freeze-thaw tests that significant changes have occurred especially in the strength and water absorption parameters of the monzogranites and that they have been affected negatively. This indicates that the monzogranites are not suited for outdoor use as building stone in regions such as the Gümüşhane province and regions with similar climate characteristics, but that they can be used in a lot of regions with more moderate climates. As a building stone, monzogranites can be used either as cobblestone, curbstone, or paving stone subject to their mean block volume. It is considered that the widespread of the Gümüşhane Granitoid may provide a substantial economical income to the country.
AtıfScopus5OpenAlex5İncele - MakaleYalnız künye2020Scopus SJRQ2Effects of kinesio tape application on pain, anxiety, and menstrual complaints in women with primary dysmenorrhea: A randomized sham-controlled trial
Toprak Celenay, Seyda; Kavalci, Basak; Karakus, Aysenur; Alkan, Afra
Aim: To investigate the effects of kinesio tape (KT) application on pain, anxiety, and menstrual complaints in women with PD and compare this application with control and sham tape (ST). Methods: Fifty-one women with PD were randomized into three groups: KT, ST, and control groups. No tape application was performed in the control group. KT was applied on the sacral and suprapubic regions with the ligament technique in the KT group, while it was applied on the trochanter major with no technique in the ST group. Pain, anxiety level, and menstrual complaints were assessed before and after the applications. Results: The decreases in pain, anxiety levels, and some menstrual complaints after the application were higher in the KT group than those in the other two groups (p < 0.05). Conclusion: KT application seems to be an effective method in decreasing pain, anxiety level, and some menstrual complaints in women with PD.
AtıfScopus23WoS18OpenAlex28İncele - MakaleYalnız künye2020Scopus SJRQ3Simultaneous quadrotor autopilot system and collective morphing system design
Kose, Oguz; Oktay, Tugrul
Purpose: The purpose of this paper is to design a quadrotor with collective morphing using the simultaneous perturbation stochastic approximation (SPSA) optimization algorithm. Design/methodology/approach: Quadrotor design is made by using Solidworks drawing program and some mathematical performance relations. Modelling and simulation are performed in Matlab/Simulink program by using the state space model approaches with the parameters mostly taken from Solidworks. Proportional integral derivative (PID) approach is used as control technique. Morphing amount and the best PID coefficients are determined by using SPSA algorithm. Findings: By using SPSA algorithm, the amount of morphing and the best PID coefficients are determined, and the quadrotor longitudinal and lateral flights are made most stable via morphing. Research limitations/implications: It takes quite a long time to model the quadrotor in Solidworks and Matlab/Simulink with the state space model and using the SPSA algorithm. However, this situation is overcome with the proposed model. Practical implications: Optimization with SPSA is very useful in determining the amount of morphing and PID coefficients for quadrotors. Social implications: SPSA optimization method is useful in terms of cost, time and practicality. Originality/value: It is released to improve performance with morphing, to determine morphing rate with SPSA algorithm and to determine PID coefficients accordingly.
AtıfScopus67WoS64OpenAlex70İncele - MakaleAçık Erişim2021A determination of the relationship between the symptoms, hospital anxiety and depression levels, and quality of life patients diagnosed with Covid-19
Sayilan, Samet; Aydin Sayilan, Aylin; Demir Doğan, Melike; Çetinkaya, Emel; Olcayturk, Nuray
Introduction: The worldwide spread of coronavirus over the last 20 years has resulted in its becoming a major threat to health. The virus is thought to be a zoonotic disease spread by means of direct and contact transmission. The purpose of this study was to investigate the symptoms, anxiety-depression levels, and quality of life of patients with Covid-19. Material and methods: This descriptive, cross-sectional research was conducted in an education and research hospital between August and November 2020. An information form, the Hospital Anxiety and Depression Scale, and the Quality of Life Scale were employed as data collection tools. The study was completed with 103 individuals. Results: The mean age of the patients enrolled in the study was 37.77±10.92 years, and 67% were women. Higher anxiety levels were determined in women compared to men (p=0.001) and in married participants compared to unmarried individuals (p=0.010). Significant negative correlation was determined between anxiety and the Quality of Life Scale sub-parameters of general health, physical health, psychological health, and environment. Positive correlation was found between Covid-19 severity and anxiety, and negative correlation between Covid-19 severity and physical health (p<0.001). Conclusion: Higher anxiety was determined among women and married patients in this study, and quality of life (in the four sub-parameters) decreased as anxiety increased. Physical health decreased, while anxiety increased, with the severity of Covid.
