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Article Citation - WoS: 2Citation - Scopus: 2A Note on Public Investment, Public Debt, and Macroeconomic Performance(Cambridge Univ Press, 2011) Ismihan, Mustafa; Ozkan, F. GulcinThis paper provides an assessment of public capital spending within a macroeconomic policy model with explicit monetary and fiscal interactions, in contrast to most of the existing analyses of public investment that utilize "real" general equilibrium models. As such, we are able to consider the interactions of public investment with inflation, taxation, and public debt. Our results indicate that a clear trade-off exists between the costs and benefits of public investment, as is the case in the existing literature. However, the use of a monetary-fiscal policy model rather than a "real" general equilibrium one enables us to trace the macroeconomic channels including monetary ones through which these costs and benefits are transmitted to the rest of the economy. To the extent that these costs and benefits vary between countries, our results provide a potential explanation for the mixed empirical findings on the real effects of public capital spending.Article A boundary value problem for second-order nonlinear difference equations on the integers(Cambridge Univ Press, 2005) Dal, F; Guseinov, GSIn this study, we are concerned with a boundary value problem (BVP) for nonlinear difference equations on the set of all integers Z, under the assumption that the left-hand side is a second-order linear difference expression which belongs to the so-called Weyl-Hamburger limit-circle case. The BVP is considered in the Hilbert space l(2) and includes boundary conditions at infinity. Existence and uniqueness results for solution of the considered BVP are established.Article Citation - Scopus: 1Air Refueling Optimisation for More Agile and Efficient Military Deployment Operations(Cambridge Univ Press, 2022) Toydas, M.; Malyemez, C.Strategic airlift is a crucial capability for any country that wants to protect its global interests around the world. Air refueling may offer more agile and efficient airlift capabilities by increasing cargo aircraft payload and shortening airlift time. We investigated whether air refueling can shorten the total time of an airlift operation and decrease the number of cargo aircraft sorties required in a deployment scenario, especially where the distance between origin and destination is within the range of cargo aircraft. We introduced two mathematical models to compare the total airlift time and number of cargo aircraft required for given origin-destination and tanker base locations and total freight to be moved. We optimised initial cargo and fuel amount for cargo aircraft along with rendezvous point coordinates to minimise total airlift time. We used a numerical example to show that substantial airlift time and cargo aircraft sortie savings are possible through air refueling.Article On the Resolvent of the Laplace-Beltrami Operator in Hyperbolic Space(Cambridge Univ Press, 2015) Guseinov, Gusein Sh.In this paper, a detailed description of the resolvent of the Laplace-Beltrami operator in n-dimensional hyperbolic space is given. The resolvent is an integral operator with the kernel (Green's function) being a solution of a hypergeometric differential equation. Asymptotic analysis of the solution of this equation is carried out.Article Citation - WoS: 1Citation - Scopus: 1Cold War Aviation: American Technology Transfer and the Construction of Turkey's First International Civilian Airport in Yeşilköy, Istanbul, 1944-1953(Cambridge Univ Press, 2024) Tunc, Tanfer Emin; Tunc, GokhanWith the economic and political support of the United States, in July 1947, Turkey signed contracts withthe Westinghouse Electric International Company and J.G. White Engineering Corporation to constructits first international civilian airport, Istanbul'sYe & scedil;ilk & ouml;y Airport. As this article will argue, the buildingof Ye & scedil;ilk & ouml;y (1949-53), through a partnership with two American engineering firms, is essentially anearly Cold War narrative of transnational exchange involving the multidirectional flow of technicalknowledge, expertise and resources between the United States and Turkey; the circulation of geopol-itically significant (and frequently competing) military, civilian and government actors; and thelocal and global implications of these transmissions. Yet the Ye & scedil;ilk & ouml;y construction narrative also illus-trates how post-war technology transfer was a highly political process of constant adaptation, modifi-cation and negotiation. Fraught with unforeseen friction and thorny challenges, Ye & scedil;ilk & ouml;y exemplifiesthe complicated American Cold War strategy of creating and maintaining alliances through engineeringknowledge, personnel and practices, often with unintended consequences. Moreover, as a case study,Ye & scedil;ilk & ouml;y opens a new window into the cautious science diplomacy that occurred along the IronCurtain, while filling a notable historiographic gap with respect to aviation in early Cold War Turkey.Article Citation - WoS: 1Citation - Scopus: 2Determination of Disaster Response Self-Efficacy and Related Factors of Nurses Working in Surgical Clinics(Cambridge Univ Press, 2025) Kulekci, Emel; Tamer, Fazilet; Tug, OzgurObjectives Disasters experienced in the world and in our country in recent years have made it necessary for health professionals to have high levels of disaster response self-efficacy. Nurses, as an important member of the health care team, have a key role in disaster management, especially in disaster response. Therefore, it is extremely important for nurses to be ready for disaster response and to have high levels of self-efficacy in disaster response. This study was conducted to determine the disaster response self-efficacy status and related factors of nurses working in surgical clinics.Methods This descriptive cross-sectional study was conducted with 127 nurses working in surgical clinics between June and August 2023. "Sociodemographic Data Collection Form" was used to determine the sociodemographic characteristics of the nurses and "Of the Disaster Response Self-efficacy Scale" was used to assess their disaster response self-efficacy.Results The findings of the study show that nurses working in surgical clinics have a high level of disaster preparedness. Previous on-duty disaster experience and feeling competent about disaster are positively associated with disaster response self-efficacy.Conclusions It may be recommended to provide evidence-based, high-quality, and up-to-date training programs at regular intervals to increase and maintain the emergency response competencies of nurses. The originality of this study is that it was conducted only with surgical nurses.Article Citation - WoS: 3Citation - Scopus: 2Cross-Sectional Determinants of Lactose-Free Food Awareness and Purchase Among Adult Consumers(Cambridge Univ Press, 2023) Yilmaz, Birsen; Agaguenduez, Duygu; Kalyoncu Atasoy, Z. Begum; Yesilyurt, Neslihan; Ergin, Sule; Murat, NaciThis research was conducted to evaluate the knowledge and purchasing behaviour of consumers regarding lactose-free foods. Study data were collected from 1882 individuals with the help of a questionnaire form. Attitudes towards animal welfare, healthy nutrition and gastrointestinal symptoms were also evaluated. The majority (86.6%) of the participants reported that they had heard of the concept of lactose-free foods before, but more than half (67.0%) did not report buying them because of their higher costs compared to regular products and lack of sufficient information. Not causing gas/bloating (32.5%) and being healthier (28.3%) were shown to be the most significant motivational factors in purchasing lactose-free foods (P < 0.05). The factors affecting purchase of lactose-free products were education, employment status, history of having a food intolerance test and animal welfare perception together with higher scores from the gastrointestinal symptom rating scale, and attitude scale for healthy nutrition (P < 0.05). Body mass index was not found to be an effective factor determining purchase intention. The results provide a general overview of consumers, however, further studies on other demographic groups are needed.Article Citation - WoS: 1Citation - Scopus: 2Computing Minimal Signature of Coherent Systems Through Matrix-Geometric Distributions(Cambridge Univ Press, 2021) Eryilmaz, Serkan; Eryılmaz, Serkan; Tank, Fatih; Eryılmaz, Serkan; Industrial Engineering; Industrial EngineeringSignatures are useful in analyzing and evaluating coherent systems. However, their computation is a challenging problem, especially for complex coherent structures. In most cases the reliability of a binary coherent system can be linked to a tail probability associated with a properly defined waiting time random variable in a sequence of binary trials. In this paper we present a method for computing the minimal signature of a binary coherent system. Our method is based on matrix-geometric distributions. First, a proper matrix-geometric random variable corresponding to the system structure is found. Second, its probability generating function is obtained. Finally, the companion representation for the distribution of matrix-geometric distribution is used to obtain a matrix-based expression for the minimal signature of the coherent system. The results are also extended to a system with two types of components.Article Citation - WoS: 2Citation - Scopus: 1Prediction of the Onset of Shear Localization Based on Machine Learning(Cambridge Univ Press, 2023) Akar, Samet; Ayli, Ece; Ulucak, Oguzhan; Ugurer, DorukPredicting the onset of shear localization is among the most challenging problems in machining. This phenomenon affects the process outputs, such as machining forces, surface quality, and machined part tolerances. To predict this phenomenon, analytical, experimental, and numerical methods (especially finite element analysis) are widely used. However, the limitations of each method hinder their industrial applications, demanding a reliable and time-saving approach to predict shear localization onset. Additionally, since this phenomenon largely depends on the type and parameters of the constitutive material model, any change in these parameters requires a new set of simulations, which puts further restrictions on the application of finite element modeling. This study aims to overcome the computational efficiency of the finite element method to predict the onset of shear localization when machining Ti6Al4V using machine learning methods. The obtained results demonstrate that the FCM (fuzzy c-means) clustering ANFIS (adaptive network-based fuzzy inference system) has given better results in both training and testing when it is compared to the ANN (artificial neural network) architecture with an R-2 of 0.9981. Regarding this, the FCM-ANFIS is a good candidate to calculate the critical cutting speed. To the best of the authors' knowledge, this is the first study in the literature that uses a machine learning tool to predict shear localization.Article Citation - WoS: 6Citation - Scopus: 7DISTRIBUTIONS OF RANDOM VARIABLES INVOLVED IN DISCRETE CENSORED δ-SHOCK MODELS(Cambridge Univ Press, 2023) Chadjiconstantinidis, Stathis; Eryilmaz, SerkanSuppose that a system is affected by a sequence of random shocks that occur over certain time periods. In this paper we study the discrete censored delta-shock model, delta <= 1 , for which the system fails whenever no shock occurs within a -length time period from the last shock, by supposing that the interarrival times between consecutive shocks are described by a first-order Markov chain (as well as under the binomial shock process, i.e., when the interarrival times between successive shocks have a geometric distribution). Using the Markov chain embedding technique introduced by Chadjiconstantinidis et al. (Adv. Appl. Prob. 32, 2000), we study the joint and marginal distributions of the system's lifetime, the number of shocks, and the number of periods in which no shocks occur, up to the failure of the system. The joint and marginal probability generating functions of these random variables are obtained, and several recursions and exact formulae are given for the evaluation of their probability mass functions and moments. It is shown that the system's lifetime follows a Markov geometric distribution of order (a geometric distribution of order under the binomial setup) and also that it follows a matrix-geometric distribution. Some reliability properties are also given under the binomial shock process, by showing that a shift of the system's lifetime random variable follows a compound geometric distribution. Finally, we introduce a new mixed discrete censored delta -shock model, for which the system fails when no shock occurs within a -length time period from the last shock, or the magnitude of the shock is larger than a given critical threshold . gamma > 0. Similarly, for this mixed model, we study the joint and marginal distributions of the system's lifetime, the number of shocks, and the number of periods in which no shocks occur, up to the failure of the system, under the binomial shock process.
