Akademik Çıktılar

Permanent URI for this communityhttps://hdl.handle.net/20.500.12416/8602

Browse

Now showing 1 - 20 of 865

Citation - WoS: 4
Citation - Scopus: 4
A Bi-Objective Integrated Mathematical Model For Blood Supply Chain: Case Of Turkish Red Crescent
(Amer inst Mathematical Sciences-aims, 2023) Satir, Benhur; Yolcu, Vahdi; 54700; Endüstri Mühendisliği
Various criteria feature in blood supply chain (BSC) designs, where cost-based and time-based are the most commonly found in the literature. In the current study, total annual cost is used together with a new time-based objective. The total time spent in the transportation of blood products is considered as time lost, and weight is given to that time according to the product amount and then normalized with respect to shelf life. In using cost and time objectives, we developed a bi-objective mixed-integer mathematical programming model for the BSC of Turkish Red Crescent (TRC, the singular authority controlling BSC throughout Turkey), including collection, production, and distribution echelons, and also considering bag-type decisions for whole-blood collection. The objective of the study was to propose a BSC design model and solution approach. With all real-life TRC instances resolved optimally, a linear programming relaxation-based heuristic was developed for large-scale problem sizes. Real-life data were obtained from the TRC and the remainder from open-to-public sources. The study's main finding is that cost and time objectives alone produce significantly different designs, whilst using them together to form efficient-frontier solutions for decision-makers adds practical value.
Citation - Scopus: 3
A close look at Newton–Cotes integration rules
(Cankaya University, 2019) Sermutlu, E.; 17647; Matematik
Newton–Cotes integration rules are the simplest methods in numerical integration. The main advantage of using these rules in quadrature software is ease of programming. In practice, only the lower orders are implemented or tested, because of the negative coefficients of higher orders. Most textbooks state it is not necessary to go beyond Boole’s 5-point rule. Explicit coefficients and error terms for higher orders are seldom given literature. Higher-order rules include negative coefficients therefore roundoff error increases while truncation error decreases as we increase the number of points. But is the optimal one really Simpson or Boole? In this paper, we list coefficients up to 19-points for both open and closed rules, derive the error terms using an elementary and intuitive method, and test the rules on a battery of functions to find the optimum all-round one. © 2019, Cankaya University. All rights reserved.
Citation - WoS: 1
Citation - Scopus: 4
A Comparative Evaluation Of Popular Search Engines On Finding Turkish Documents For A Specific Time Period
(Univ Osijek, Tech Fac, 2017) Bitirim, Yiltan; Gorur, Abdul Kadir; 107251; Bilgisayar Mühendisliği
This study evaluates the popular search engines, Google, Yahoo, Bing, and Ask, on finding Turkish documents by comparing their current performances with their performances measured six years ago. Furthermore, the study reveals the current information retrieval effectiveness of the search engines. First of all, the Turkish queries were run on the search engines separately. Each retrieved document was classified and precision ratios were calculated at various cut-off points for each query and engine pair. Afterwards, these ratios were compared with the six years ago ratios for the evaluations. Besides the descriptive statistics, Mann-Whitney U and Kruskal-Wallis H statistical tests were used in order to find out statistically significant differences. All search engines, except Google, have better performance today. Bing has the most increased performance compared to six years ago. Nowadays: Yahoo has the highest mean precision ratios at various cut-off points; all search engines have their highest mean precision ratios at cut-off point 5; dead links were encountered in Google, Bing, and Ask; and repeated documents were encountered in Google and Yahoo.
Citation - WoS: 0
Citation - Scopus: 0
A comparative research on space of women in prayer place interiors of celestial religions: Cases from istanbul
(Gazi Univ, 2020) Disli, Gulsen; Ozcan, Zuhal
Cross-cultural comparison has been used in architecture mostly to discuss the components of culture, knowledge, and value systems, yet to date there is not a specific comparative study on gendered architecture in prayer places of celestial religions, namely Judaism, Christianity, and Islam. Hence, this study aims to reveal how attendance of women in prayer places with different national, historic, religious, and cultural characteristics shaped architectural space organization and to assess potential similarities and differences of women's section in prayer spaces of celestial religions by examining literature survey, archival and historic research, including field observations. In addition to general observations in building scale, some exemplary historic synagogues, churches, and mosques in Istanbul still in use have been chosen as case studies, and their plan typologies, as well as types and locations of women's galleries/sections have been discussed. Cross-cultural comparison parameters were; development of women's section in prayer places as a structured architectural space and basic architectural terminologies used to define women's section. The major conclusion of the study is that originally women had right to worship in prayer spaces without any physical separation in all three religions, yet in time the place of women had a more defined/divided/structured character especially in Islam and Judaism. The study also indicates that while at present day, gendered architecture is still the predominant approach in Islam and in Orthodox Judaism; mix congregation in a single-unsegregated space for both sexes is more common in contemporary society of Christianity.
Citation - WoS: 3
Citation - Scopus: 3
A Comparative Study of Effects of Additive Particle Size and Content on Wetting Behavior and Brazing Performance of C/SiC Composite
(Springer, 2023) Saltik, Simge; Esen, Ziya; Dericioglu, Arcan F.; 52373; Ortak Dersler Bölümü
This study has focused on the influence of size and content of SiC particle incorporation on the wetting behavior of the Ticusil brazing filler alloy and on its brazing performance in C/SiC composite/Ti6Al4V alloy joints. The effect of the size and content of additive SiC particles on the variation of molten brazing filler alloy contact angle was recorded at various brazing time and temperatures. Moreover, the microstructural evolution and mechanical properties of the additive containing C/SiC composite/Ti6Al4V alloy joints produced by the brazing method were investigated. The contact angles in both brazing filler alloys containing nano- and micro-sized SiC particles exhibited a sudden decrease with time during isothermal holding as observed in as-received brazing filler alloys. As the quantity of the SiC particles increased in the brazing alloy, the recorded contact angle values including the final, stable contact angle increased, while the time for the drastic contact angle change also increased remarkably. Compared to as-received counterparts, the addition of 2 wt.% nano-sized SiC and 1 wt.% micro-sized SiC particles improved the shear strength of the joints by 35 and 8%, respectively. Although the recorded contact angle values were close to each other in brazing alloys containing SiC particles with different sizes (37 and 42 degrees for 1 wt.% micro-sized and 2 wt.% nano-sized additions), higher increment was achieved in the mechanical performance of the joints with nano-sized SiC additive due to more homogeneous reinforcement effect of the nanoparticles. The results indicated that the optimum brazing filler alloy contact angle for the highest shear strength is similar to 40 degrees for both nano- and micron-sized additive containing Ticusil filler alloy.
Citation - WoS: 13
Citation - Scopus: 14
A Comparative Study of Multiple Regression and Machine Learning Techniques for Prediction of Nanofluid Heat Transfer
(Asme, 2022) Kocak, Eyup; Ayli, Ece; Turkoglu, Hasmet; 283455; 265836; 12941; Makine Mühendisliği
The aim of this article is to introduce and discuss prediction power of the multiple regression technique, artificial neural network (ANN), and adaptive neuro-fuzzy interface system (ANFIS) methods for predicting the forced convection heat transfer characteristics of a turbulent nanofluid flow in a pipe. Water and Al2O3 mixture is used as the nanofluid. Utilizing fluent software, numerical computations were performed with volume fraction ranging between 0.3% and 5%, particle diameter ranging between 20 and 140 nm, and Reynolds number ranging between 7000 and 21,000. Based on the computationally obtained results, a correlation is developed for the Nusselt number using the multiple regression method. Also, based on the computational fluid dynamics results, different ANN architectures with different number of neurons in the hidden layers and several training algorithms (Levenberg-Marquardt, Bayesian regularization, scaled conjugate gradient) are tested to find the best ANN architecture. In addition, ANFIS is also used to predict the Nusselt number. In the ANFIS, number of clusters, exponential factor, and membership function (MF) type are optimized. The results obtained from multiple regression correlation, ANN, and ANFIS were compared. According to the obtained results, ANFIS is a powerful tool with a R-2 of 0.9987 for predictions.
Citation - WoS: 18
Citation - Scopus: 19
A Comparison of Iterative Fourier Transform Algorithms for Image Quality Estimation
(Optical Soc Japan, 2018) Alsaka, Dina Yaqoob; Arpali, Caglar; Arpali, Serap Altay; 20809
A comparison was established between two iterative Fourier transform algorithms (IFTAs), such as the original Gerchberg-Saxton (GS) and the mixed-region amplitude freedom (MRAF) algorithms, for the hologram reconstruction of different target images through the full reference image quality estimation (IQE) and pixel homogeneity in the Fourier plane presented theoretically and experimentally. The comparison was applied depending upon both algorithms based on a computer-generated hologram (CGH) implemented utilizing a reflective phase-modulated liquid-crystal spatial light modulator (LC-SLM) to obtain the digital kinoform holograms of the desired intensity distributions. These digital holograms were applied to reconstruct the intensity patterns for 852 nm, which represents a laser beam source. The theoretical and experimental results of the reconstructed patterns obtained using the MRAF algorithm were found to be smoother and better than the patterns obtained using the GS algorithm. Unmodulated light beam (dc term) is removed from the reconstructed patterns attributed to digital kinoform holograms of MRAF algorithm as an alternative to the theoretical and experimental results without using any additional optic equipment at the light path. Moreover, this paper discussed the full reference objective quality estimations, such as mean square error (MSE), peak signal-to-noise ratio (PSNR), structural content (SC), normalized absolute error (NAE), normalized cross correlation (NK), and homogeneity of pixels, through the contrast (Cont) and inverse difference moment (IDM) for numerical and experimental results. According to the two desired intensity distributions processed theoretically and experimentally, the results of MRAF algorithm were found to be in the highly accurate recovered phase, the quality of image was enhanced, and the dc term was decreased. Image quality estimation of full reference objective relay on the feedback algorithms experimental attestation has not been implemented yet.
Citation - WoS: 7
Citation - Scopus: 7
A Comparison of Radiation Shielding of Stainless Steel With Different Magnetic Properties
(Vinca inst Nuclear Sci, 2014) Calik, Adnan; Akbunar, Sahin; Ucar, Nazim; Yilmaz, Nihat; Karakas, Mustafa Serdar; Akkurt, Iskender; 48915; Malzeme Bilimi ve Mühendisliği
The radiation shielding properties of three different stainless steels have been investigated. For this purpose, linear attenuation coefficients at photon energy levels of 662 keV and 1250 keV have been measured. The obtained results showed that ferritic stainless steel was more capable in stopping the high energy photons than its non-magnetic counterpart.
Citation - WoS: 4
Citation - Scopus: 4
A Decomposıtıon Algorıthm Coupled Wıth Operatıonal Matrıces Approach Wıth Applıcatıons To Fractıonal Dıfferentıal Equatıons
(Vinca inst Nuclear Sci, 2021) Talib, Imran; Alam, Md Nur; Baleanu, Dumitru; Zaidi, Danish; 56389; Matematik
In this article, we solve numerically the linear and non-linear fractional initial value problems of multiple orders by developing a numerical method that is based on the decomposition algorithm coupled with the operational matrices approach. By means of this, the fractional initial value problems of multiple orders are decomposed into a system of fractional initial value problems which are then solved by using the operational matrices approach. The efficiency and advantage of the developed numerical method are highlighted by comparing the results obtained otherwise in the literature. The construction of the new derivative operational matrix of fractional legendre function vectors in the Caputo sense is also a part of this research. As applications, we solve several fractional initial value problems of multiple orders. The numerical results are displayed in tables and plots.
Citation - Scopus: 15
A Decomposition Method for Solving Q-Difference Equations
(Natural Sciences Publishing Co., 2015) Jafari, H.; Johnston, S.J.; Sani, S.M.; Baleanu, D.; 56389; Matematik
The q-difference equations are important in q-calculus. In this paper, we apply the iterative method which is suggested by Daftardar and Jafari, hereafter called the Daftardar-Jafari method, for solving a type of q-partial differential equations. We discuss the convergency of this method. In the implementation of this technique according to other iterative methods such as Adomian decomposition and homotopy perturbation methods, one does not need the calculation of the Adomian's polynomials for nonlinear terms. It is proven that under a special constraint, the given result by this method converges to exact solution of nonlinear q-ordinary or q-partial differential equations. © 2015 NSP Natural Sciences Publishing Cor.
Citation - WoS: 5
Citation - Scopus: 6
A discussion on a pata type contraction via iterate at a point
(Univ Nis, Fac Sci Math, 2020) Karapinar, Erdal; Fulga, Andreea; Rakocevic, Vladimir; 19184; Matematik
In this paper, we introduce the notion of Pata type contraction at a point in the context of a complete metric space. We observe that such contractions possesses unique fixed point without continuity assumption on the given mapping. Thus, is extended the original results of Pata. We also provide an example to illustrate its validity.
Citation - WoS: 2
Citation - Scopus: 2
A discussion on the coincidence quasi-best proximity points
(Univ Nis, Fac Sci Math, 2021) Fouladi, Farhad; Abkar, Ali; Karapinar, Erdal; 19184; Matematik
In this paper, we first introduce a new class of the pointwise cyclic-noncyclic proximal contraction pairs. Then we consider the coincidence quasi-best proximity point problem for this class. Finally, we study the coincidence quasi-best proximity points of weak cyclic-noncyclic Kannan contraction pairs. We consider an example to indicate the validity of the main result.
Citation - WoS: 22
Citation - Scopus: 22
A discussion on the role of people in global software development
(Univ Osijek, Tech Fac, 2013) Misra, Sanjay; Colomo-Palacios, Ricardo; Pusatli, Tolga; Soto-Acosta, Pedro; 51704
Literature is producing a considerable amount of papers which focus on the risks, challenges and solutions of global software development (GSD). However, the influence of human factors on the success of GSD projects requires further study. The aim of our paper is twofold. First, to identify the challenges related to the human factors in GSD and, second, to propose the solution(s), which could help in solving or reducing the overall impact of these challenges. The main conclusions of this research can be valuable to organizations that are willing to achieve the quality objectives regarding GSD projects.
Citation - WoS: 2
Citation - Scopus: 3
A Drone-Based Blood Donation Approach Using an Ant Colony Optimization Algorithm
(Tech Science Press, 2023) Abbas, Sana; Ashraf, Faraha; Jarad, Fahd; Sardar, Muhammad Shoaib; Siddique, Imran; 234808; Matematik
This article presents an optimized approach of mathematical techniques in the medical domain by manoeuvring the phenomenon of ant colony optimization algorithm (also known as ACO). A complete graph of blood banks and a path that covers all the blood banks without repeating any link is required by applying the Travelling Salesman Problem (often TSP). The wide use promises to accelerate and offers the opportunity to cultivate health care, particularly in remote or unmerited environments by shrinking lab testing reversal times, empowering just-in-time lifesaving medical supply.
Citation - WoS: 0
Citation - Scopus: 1
A Fixed Point Theorem and an Application for the Cauchy Problem in the Scale of Banach Spaces
(Univ Nis, Fac Sci Math, 2020) Vo Viet Tri; Karapinar, Erdal; 19184; Matematik
The main aim of this paper is to prove the existence of the fixed point of the sum of two operators in setting of the cone-normed spaces with the values of cone-norm belonging to an ordered locally convex space. We apply this result to prove the existence of global solution of the Cauchy problem with perturbation of the form {x'(t) = f[t, x(t)] + g[t, x(t)], t is an element of[0,infinity), x(0) = x(0)is an element of F-1, in a scale of Banach spaces f(F-s; parallel to center dot parallel to(s)) : s is an element of(0, 1]}.
Citation - WoS: 1
Citation - Scopus: 2
A fixed point theorem for a system of Pachpatte operator equations
(Springer Basel Ag, 2021) Karapinar, Erdal; Ozturk, Ali; Rakocevic, Vladimir; 19184; Matematik
In this paper, we investigate sufficient conditions for the existence of solutions to the system {Tx=x, alpha(i)(x)=0(E), i = 1,2, ... r, where 0(E) is the zero vector of E, and alpha(i) : E -> E i = 1, 2, ... , r are mappings, T is a mapping satisfying the Pachpatte-contraction.
Citation - WoS: 4
Citation - Scopus: 2
A fixed point theorem for Proinov mappings with a contractive iterate
(Zhejiang Univ Press, 2023) Karapinar, Erdal; Fulga, Andreea; 19184; Çankaya Üniversitesi, Fen - Edebiyat Fakültesi, Matematik Bölümü; Matematik
In this paper, we consider the fixed point theorem for Proinov mappings with a contractive iterate at a point. In other words, we combine and unify the basic approaches of Proinov and Sehgal in the framework of the complete metric spaces. We consider examples to illustrate the validity of the obtained result.
Citation - WoS: 2
Citation - Scopus: 1
A fixed point theorem on multiplicative metric space with integral-type inequality
(Journal Mathematics & Computer Science-jmcs, 2018) Khan, Aziz; Khan, Hasib; Baleanu, Dumitru; Jafari, Hossein; Khan, Tahir Saeed; Alqurashi, Maysaa; 56389; Matematik
In this paper, we prove fixed point theorems (FPTs) on multiplicative metric space (MMS) (X, triangle) by the help of integral-type contractions of self-quadruple mappings (SQMs), i.e., for p(1), p(2), p(3), p(4) : X -> R. For this, we assume that the SQMs are weakly compatible mappings and the pairs (p(1), p(3)) and (p(2), p(4)) satisfy the property (CLRp3p4). Further, two corollaries are produced from our main theorem as special cases. The novelty of these results is that for the unique common fixed point (CFP) of the SQMs p(1), p(2), p(3), p(4), we do not need to the assumption of completeness of the MMS (X, triangle). These results generalize the work of Abdou, [A. A. N. Abdou, J. Nonlinear Sci. Appl., 9 (2016), 2244-2257], and many others in the available literature.
Citation - Scopus: 3
A fixed point theorem without a Picard operator
(Cankaya University, 2021) Karapınar, E.; 19184; Matematik
In this short note, we propose a fixed point theorem in the setting of a Banach space without using a Picard operator. © 2021, Cankaya University. All rights reserved.
Citation - WoS: 5
Citation - Scopus: 7
A FRACTIONAL STUDY OF MHD CASSON FLUID MOTION WITH THERMAL RADIATIVE FLUX AND HEAT INJECTION/SUCTION MECHANISM UNDER RAMPED WALL CONDITION: APPLICATION OF RABOTNOV EXPONENTIAL KERNEL
(Sciendo, 2024) Rehman, Aziz Ur; Jarad, Fahd; Riaz, Muhammad Bilal; 234808; Matematik
The primary objective of this research is to extend the concept of fractionalized Casson fluid flow. In this study, a comprehensive analysis of magnetohydrodynamic (MHD) natural convective flow of Casson fluid is conducted, focusing on obtaining analytical solutions using the non-integer-order derivative known as the Yang-Abdel-Aty-Cattani (YAC) operator. The YAC operator utilized in this research possesses a more generalized exponential kernel. The fluid flow is examined in the vicinity of an infinitely vertical plate with a characteristic velocity denoted as u(0). The mathematical modelling of the problem incorporates partial differential equations, incorporating Newtonian heating and ramped conditions. To facilitate the analysis, a suitable set of variables is introduced to transform the governing equations into a dimensionless form. The Laplace transform (LT) is then applied to the fractional system of equations, and the obtained results are presented in series form and also expressed in terms of special functions. The study further investigates the influence of relevant parameters, such as alpha, beta, P-r, Q, Gr, M, N-r and K, on the fluid flow to reveal interesting findings. A comparison of different approaches reveals that the YAC method yields superior results compared to existing operators found in the literature. Graphs are generated to illustrate the outcomes effectively. Additionally, the research explores the limiting cases of the Casson and viscous fluid models to derive the classical form from the YAC fractionalized Casson fluid model.

Browse

Browsing Akademik Çıktılar by Scopus Q "Q3"