TR Dizin İndeksli Yayınlar Koleksiyonu / TR Dizin Indexed Publications Collections

Permanent URI for this collectionhttps://hdl.handle.net/20.500.13091/4

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Citation - WoS: 1
Citation - Scopus: 5
An Application on the Use of Fuzzy Multi Criteria Decision Making Methods for Software Project Development Process Selection
(Gazi Univ, Fac Engineering Architecture, 2023) Yel, İbrahim; Baysal, Mehmet Emin
Software development projects are difficult to manage, as they involve complex business stages and the resources used are made up of real people. Along with the specifications of the projects, organizational variables and the competencies of the team members are among the factors that will directly affect the success of the project. It is thought that the success of software development projects will increase with the use of these three factors in the solution of the software development process method selection problem. In the management of software projects, different process methods are used, including Agile and Waterfall (Traditional) Methods. It is important to assign development teams to projects according to their abilities and to rank the projects among themselves. As a first step in this study, the weights of the criteria were determined using the fuzzy AHP. Then fuzzy WASPAS, fuzzy EDAS and Interval Neutrosophic Z Numbers (NZN) methods were used to rank projects and employees. According to the results of this research with sensitivity analysis, it has been determined that if the software development method decision is implemented, the number of defects and their solutions can be improved by 4.2%-6%, 5.8%-7.3% and 6.8%-9.7% when compared to the actual values of person-day values.
Citation - Scopus: 1
Determination of Environmental Valuation of Bey?ehir Lake National Park by Travel Cost and Contingent Valuation Methods
(Gazi Univ, Fac Engineering Architecture, 2023) Karakayacı, Zühal; Karakayacı, Özer; Polat, Ahmet Tugrul
With the increasing population of the world, developments such as unplanned growth, urbanization, industrialization and accordingly climate change have necessitated the protection of natural resources. In this context, National Parks are the leading natural resources under protection. Since national parks are natural assets used for recreational and tourism purposes, they provide important contributions to the country's economy as well as the social benefit they provide to the society. Therefore, natural resources need to be included in the calculations of national income, which is a measure of the growth rate of countries, and economic value determination is needed for this. For this purpose, Beysehir Lake National Park, which is the second largest national park, has been valued. Contingent Valuation Method and Travel Cost Method are used in the appraisal. During the data collection phase, 383 samples were determined using the Proportional Sampling Method, and the surveys were conducted with visitors within the national park in the summer of 2019. According to the Conditional Valuation Method, 186.838.123 TL was calculated, 453.612.000 TL according to the Travel Cost Method and the total economic value was determined as 640.450.123 TL. The consumer surplus per visitor, that is, the fee that a visitor is willing to pay for a visit to the national park in one year, was calculated as 2.202 TL. All findings obtained with a stake in the country's national income in light of the economic value of Turkey and the second largest national park was revealed the existing potential. Its economic value should be evaluated in development policies, and its existing potential should be presented to the social benefit of people by protecting it within the framework of environmental protection policies.
Citation - WoS: 1
Citation - Scopus: 1
Effects of Conventional and Flash Sintering Methods on the Properties of Zro₂-sno₂nanocomposites
(Gazi Univ, Fac Engineering Architecture, 2024) Cetinkaya, Zeynep
ZrO2-SnO2 nanocomposite was produced in nanofiber (NF) form in three different ratios by volume (%v/v)by electro-spinning technique. Microstructure and morphological characterization of NFs reveal the ternarysystem of ZrO2-SnO2-ZrSnO4. Also, when the composition ratio of NFs was changed, both the band gap andthe electrical (flash) sintering (ES or FS) event affected the temperature and sinter time variation. FSexperiments were used at 3.77mA/mm2 current cutoff under thermal (844-878 degrees C) and electric field(420V/mm). Highly dense nanocomposites were obtained in less than 80 seconds with a maximum powerabsorption of 1.58W/mm3. Thanks to the low sintering temperature and time, the nanostructured surfacemorphology of the nanocomposites was obtained. In addition to the FS process, ZrO2-SnO2-ZrSnO4 CNFs were sintered for 1 hour at 1200 degrees C using the conventional sintering (GS) method. This study investigatedthe effects of the difference in sintering techniques on the sintering temperature and time, as well as onproperties such as density and hardness. As the amount of Sn (%v/v) in the composition increases, the density increases, but the hardness value decreases. It has been proven that in ZrO2-SnO2-ZrSnO4 CNFs, denser and harder compositions are obtained with FS treatment compared to GS. When all these results are evaluated, it is believed that the synthesized nanocomposites can be used as a valid candidate in the health system such as dental implants due to their antimicrobial effect and non-toxicity in the model organism
Citation - WoS: 7
Citation - Scopus: 10
Flash Sintering Effect on Fly Ash Microstructure
(Gazi Univ, Fac Engineering Architecture, 2022) Cetinkaya, Zeynep
In this study, densification of fly ash, (FA, industrial waste glass ceramic material) powder is carried out by electric field assisted flash sintering method. FA obtained from Tuncbilek Thermal Power Plant (Kutahya, Turkey). During the flash sintering experiment, 450 V/mm electric field is applied on sample with 0.85 amp current cutoff value. Flash sintering is accomplished in 70 sec at approximate to 1137 degrees C. According to XRD analysis, glassy phase, quartz, hematite, magnetite, magnesioferrite and mullite structures are in the structure. Based on the results of chemical analysis (XRF), reported in the literature, the sintering of ceramic materials formed by SiO2, Al2O3 and Fe2O3 individually or all together occurs at temperatures of 1500 degrees C and above. By electric field assisted flash sintering technique, the sintering temperature is decreased from 1500 to 1137 degrees C along with a decrement in sintering time from 3 hours to 70 seconds. The sintering process with this method was performed at a lower temperature and in a shorter time than traditional sintering methods. With the SEM micrographs, it has been proven that fly ash flash sintering processes have a denser structure compared to the conventional sintering.
Citation - WoS: 2
Citation - Scopus: 2
Investigation of Tribological Performances of Ep Oil Additive With Gelatin and Pva Coated Nanoparticles
(Gazi Univ, Fac Engineering Architecture, 2023) Abushrenta, Hamza Mohamed S.; Kabave Kılınçarslan, Sena; Korkmaz, Seyma; Şirvan, Onur Can; Çetin, M. Hüseyin
In this study, the effect of the lubricant prepared by adding EP and silver nanoparticles (AgNP) coated with different ligands to the ethylene glycol (EG) liquid on the tribological performance of the bearing material made of CuSn10Zn tin bronze was investigated. For the tribological analysis of EP additive, the optimum EP ratio was determined by carrying out wear tests in dry medium, pure EG and lubricant media prepared by adding volume of 5%, 10%, 15% EP to EG liquid. Optimum AgNP concentration and ligand material were determined by using volume of 2%, 5% and 8% AgNP coated with different ligands together with the determined optimum EP. In both stages, where optimum EP and AgNP concentrations were determined, the experiments were carried out with a reciprocating tribometer (ball on plate) with a load of 20 N and a speed of 40 rpm. Experiment results were analyzed by comparing friction coefficient, wear volume values with SEM and 3D topography images. According to the analysis results, it was determined that the friction coefficient and wear volume values obtained in EG + 5% EP environment were lower than 10% and 15% concentrations. According to the results obtained from the interaction of EG + 5% EP with AgNP, the optimum AgNP concentration was determined as 2%, and the optimum ligand material was determined as gelatin (Gel). In EG + 5% EP + 2% AgNP_Gel conditions, the friction coefficient was reduced by 18.70% and the volume loss by 16.94% compared to EG.
Citation - Scopus: 1
A K-Elm Approach To the Prediction of Number of Students Taking Make-Up Exams
(Gazi Univ, Fac Engineering Architecture, 2022) Kıran, Mustafa Servet; Sıramkaya, Eyup; Esme, Engin
Purpose: The main objective of this study is to present a novel problem, and novel methodology to solve this problem. The problem is to predict the number of students who fail the course and will join the make-up exams. Theory and Methods: The number of students who fail the course should take a make-up exam, but some of them do not join these exams due to internal or external motivations, and this causes waste of resources. Majority of voting-based extreme learning machines have been proposed to solve the problem, and the ELM parameters have been optimized by artificial bee colony algorithm. Results: The proposed approach shows better performance than the extreme learning machines in terms of classification accuracy. Conclusion: Before the scheduling make-up exams, the number of students who will join the exams should be predicted by the proposed or similar approaches in order to use resources efficiently.

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