Mühendislik Fakültesi
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Article Citation - WoS: 16Citation - Scopus: 19Comparative analysis of multicriteria decision making methods for postgraduate student selection(Anı Yayıncılık, 2010) Altunok, Taner; Ozpeynirci, Ozgur; Kazancoglu, Yigit; Yilmaz, Recai; 44215; 55338; 06.06. Makine Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya ÜniversitesiProblem Statement: The educational recourses available for postgraduate education are limited compared with the resources for undergraduate education. An academic advisor is required for each graduate student. The academic staff allocates an important portion of his/her time for graduate studies of his/her students. Since the number of academic staff is limited, the number of graduate students should be limited, too. While a large number of students may attend an undergraduate course, this may not be possible for some graduate courses, which are designed especially for small student groups. Hence, the selection of postgraduate students is an important problem. The postgraduate student selection problem can be defined as selecting a subset of students from the applicants for a postgraduate program. Naturally, this problem is a multi-criteria decision-making problem since each applicant has several attributes and these attributes should be considered simultaneously during the selection process. Purpose of Study: The purpose of this study is to compare the performance of different multi criteria decision-making methods developed for ranking alternatives for the postgraduate student selection problem. The best method will also be used in the student selection process for the Defense Sciences Institute of Turkish Military Academy. Methods: This paper discusses three multi-criteria decision making methods developed for ranking alternatives, namely Analytic Hierarchy Process (AHP), Weighted Product (WP) and the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). A performance measure is defined and the performance values of the methods are compared using real data gathered from the graduates of Defense Sciences Institute of Turkish Military Academy for illustration purposes. Findings and Results: According to the findings, AHP is the best of the three competitors. The ranking obtained by AHP is quite similar to the ranking of students with respect to their cumulative grade point average (CGPA) after their graduation from the program. Conclusions and Recommendations: Considering graduate student selection problem as a multicriteria decision-making problem is very important and enables universities to enroll graduate students with important attributes and a variety of strengths. This paper compares the performance of different multicriteria decision-making methods on graduate student selection problem using a single performance measure. A further study can be making such a comparison with multiple performance measuresConference Object Effects of Floating Rafts as Anti-Vortex Devices at Horizontal Intakes(International Association for Hydro-Environment Engineering and Research, 2023) Gogus, Mustafa; Gokmener, Serkan; 6062; 01. Çankaya ÜniversitesiAir- entraining vortices created by swirling flows on intakes cause serious problems such as; increasing loss of hydraulic load and discharge at water intake structures, loss of efficiency, operational problems, cavitation and vibration problems in hydraulic machines. Hence the position of the intake should be justified for the most critical scenario as the reservoir is at dead or at minimum storage level to avoid the occurrence of air-entraining vortices. Although intakes are designed by considering the formation of air-entraining vortices, they cannot be prevented due to approach flow conditions and submergence. Therefore, some structural changes should be considered in order to avoid the occurrence of air-entraining vortices. One of these methods is using anti-vortex devices to prevent the formation of air-entraining vortices. In this experimental study, floating rafts at different sizes were tested as anti-vortex devices to prevent the formation of air-entraining vortices at single and multiplehorizontal intake structures under symmetrical and asymmetrical approach flow conditions. Three identical pipes of diameter Di=0.265 m were tested at a wide range of discharge with varying sidewall clearances. Experiments were conducted for three different combinations of the intake structures: single, double and triple water intakes were operated, respectively. Different side wall distances in the approach channels of the intake structures were specified previously to create symmetrical and asymmetrical flow conditions. The side walls were located according to these distances before each experiment. For single and double water intake structures, Wraft=10 cm and triple water intake structures, Wraft=20 cm raft width were found to be successful for vortex prevention. Moreover, Wrafts/Di values that gave successful results are 0.38 for single and double intake structures and 0.75 for triple intake structures. © 2023 IAHR – International Association for Hydro-Environment Engineering and ResearchArticle Citation - WoS: 14Citation - Scopus: 19Existence Theory and Numerical Simulation of HIV-I Cure Model with New Fractional Derivative Possessing a Non-Singular Kernel(Springeropen, 2019) Aliyu, Aliyu Lsa; Alshomrani, Ali Saleh; Li, Yongjin; Inc, Mustafa; Baleanu, Dumitru; 02.02. Matematik; 02. Fen-Edebiyat Fakültesi; 01. Çankaya ÜniversitesiIn this research work, a mathematical model related to HIV-I cure infection therapy consisting of three populations is investigated from the fractional calculus viewpoint. Fractional version of the model under consideration has been proposed. The proposed model is examined by using the Atangana-Baleanu fractional operator in the Caputo sense (ABC). The theory of Picard-Lindelof has been employed to prove existence and uniqueness of the special solutions of the proposed fractional-order model. Further, it is also shown that the non-negative hyper-plane a positively invariant region for the underlying model. Finally, to analyze the results, some numerical simulations are carried out via a numerical technique recently devised for finding approximate solutions of fractional-order dynamical systems. Upon comparison of the numerical simulations, it has been demonstrated that the proposed fractional-order model is more accurate than its classical version. All the necessary computations have been performed using MATLAB R2018a with double precision arithmetic.Book Part Citation - Scopus: 1Information theory perspective of polar codes and polar encoding(Springer Science and Business Media B.V., 2019) Gazi, Orhan; 102896; 06.02. Elektronik ve Haberleşme Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya ÜniversitesiPolar codes are one of the recently discovered capacity achieving channel codes. What makes the polar codes different from other channel codes is that polar codes are designed mathematically and their performance are mathematically proven. © Springer Nature Singapore Pte Ltd. 2019.Article Citation - Scopus: 10O(N) Algorithms in Tight-Binding Molecular-Dynamics Simulations of the Electronic Structure of Carbon Nanotubes(2003) Dereli, G.; Özdoǧan, C.; 09.01. Ortak Dersler Bölümü; 09. Rektörlük; 01. Çankaya ÜniversitesiThe O(N) and parallelization techniques have been successfully applied in tight-binding moleculardynamics simulations of single-walled carbon nanotubes (SWNT's) of various chiralities. The accuracy of the O(N) description is found to be enhanced by the use of basis functions of neighboring atoms (buffer). The importance of buffer size in evaluating the simulation time, total energy, and force values together with electronic temperature has been shown. Finally, through the local density of state results, the metallic and semiconducting behavior of (10 X 10) armchair and (17 X 0) zigzag SWNT's, respectively, has been demonstrated.Conference Object Propagation of a Generalized Beam in Abcd System(World Acad Sci, Eng & Tech-Waset, 2005) Eyyuboglu, Halil Tanyer; 7688; Elektronik ve Haberleşme Mühendisliği; 06.02. Elektronik ve Haberleşme Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya ÜniversitesiFor a generalized Hermite sinosiodal/hyperbolic Gaussian beam passing through an ABCD system with a finite aperture, the propagation properties are derived using the Collins integral. The results are obtained in the form of intensity graphs indicating that previously demonstrated rules of reciprocity are applicable, while the existence of the aperture accelerates this transformation.Book Citation - Scopus: 11Sampling of Continuous Time Signals(Springer Science and Business Media B.V., 2018) Gazi, O.; 06.02. Elektronik ve Haberleşme Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya ÜniversitesiConference Object Strategy Creation, Decomposition and Distribution in Particle Navigation: Memory Module(IFAC Secretariat, 2005) Beldek, U.; Leblebicioglu, K.; 06.08. Mekatronik Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesiin particle navigation problem strategy development is crucial. The difficulties encountered by the particles during their navigation tasks require different approaches in problem solving. One way to overcome the difficulties is to divide the problem into simple modules and develop solutions for these modules separately. Basically, two different modules are sufficient in addition to the main body to develop a successful solver. The first module (conflict module), which is developed by genetic programming, is used when the particles are in conflict. The second module (memory module) helps the particles to escape from local regions. Copyright © 2005 IFAC.Book Review Citation - WoS: 4Citation - Scopus: 5The Theory of the Boundary Diffraction Wave(Elsevier Academic Press inc, 2011) Umul, Yusuf Ziya; 06.02. Elektronik ve Haberleşme Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
