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Article Citation - WoS: 8Citation - Scopus: 11g-metric Spaces in Any Number of Arguments and Related Fixed-Point Theorems(Springer international Publishing Ag, 2014) Roldan, Antonio; Karapinar, Erdal; Kumam, PoomInspired by the notion of Mustafa and Sims' G-metric space and the attention that this kind of metric has received in recent times, we introduce the concept of a G-metric space in any number of variables, and we study some of the basic properties. Then we prove that the family of this kind of metric is closed under finite products. Finally, we show some fixed-point theorems that improve and extend some well-known results in this field.Article A Note on the Generalized Matsumoto Relation(2017) Dalyan, Elif; Medetoğulları, Elif; Pamuk, MehmetcikWe give an elementary proof of a relation, first discovered in its full generality by Korkmaz, in the mapping class group of a closed orientable surface. Our proof uses only the well-known relations between Dehn twists.Article Magnetic Resonance Arthrographic Demonstration of Extension of Labral Defects in Paraglenoid Labral Cysts(Assoc Medica Brasileira, 2023) Kaya, Serhat; Ogul, Hayri; Koksal, Ali; Koru, Ahmet; Kiziloglu, Alper; Kantarci, MecitOBJECTIVE: This study aimed to investigate the extension of labral tears associated with paraglenoid labral cysts by magnetic resonance arthrography. METHODS: The magnetic resonance and magnetic resonance arthrography images of patients with paraglenoid labral cysts who presented to our clinic between 2016 and 2018 were examined. In patients with paraglenoid labral cysts, the location of the cysts, the relation between the cyst and the labrum, the location and extent of glenoid labrum damage, and whether there was contrast medium passage into the cysts were investigated. The accuracy of magnetic resonance arthrographic information was evaluated in patients undergoing arthroscopy. RESULTS: In this prospective study, a paraglenoid labral cyst was detected in 20 patients. In 16 patients, there was a defect in the labrum adjacent to the cyst. Seven of these cysts were adjacent to the posterior superior labrum. In 13 patients, there were contrast solution leak into the cyst. For the remaining seven patients, no contrast-medium passage was observed in the cyst. Three patients had sublabral recess anomalies. Two patients had rotator cuff muscle denervation atrophy accompanying the cysts. The cysts of these patients were larger compared to those of the other patients. CONCLUSION: Paraglenoid labral cysts are frequently associated with the rupture of the adjacent labrum. In these patients, symptoms are generally accompanied by secondary labral pathologies. Magnetic resonance arthrography can be successfully used not only to demonstrate the association of the cyst with the joint capsule and labrum, but also to reliably demonstrate the presence and extension of labral defects.Article Citation - WoS: 17Citation - Scopus: 24The New Middle Class in Emerging Markets: How Values and Demographics Influence Discretionary Consumption(Wiley, 2019) Belbag, Aybegum G.; Uner, M. Mithat; Cavusgil, Erin; Cavusgi, S. Tamer; Cavusgil, S. TamerThe rise of new middle-class consumers in rapidly transforming emerging markets has attracted the attention of Western business executives. What they know about this growing segment of customers will determine whether they succeed or fail in these markets. The present study examines the factors that drive the discretionary consumption of this new middle class, including the effects of consumerist values, religious values, occupation, education levels, and ownership of fixed assets. The study draws its insights from data gathered from 391 new middle-class consumers in Ankara, the second-largest city in Turkey. The findings provide important implications for businesses, both indigenous and foreign. An overall implication is that managers ought to understand and qualify the new middle class in emerging markets not simply by their access to disposable income but by deeper attitudinal and behavioral characteristics.Data Paper Citation - WoS: 44Citation - Scopus: 64A Database for the Radio Frequency Fingerprinting of Bluetooth Devices(Mdpi, 2020) Uzundurukan, Emre; Dalveren, Yaser; Kara, AliRadio frequency fingerprinting (RFF) is a promising physical layer protection technique which can be used to defend wireless networks from malicious attacks. It is based on the use of the distinctive features of the physical waveforms (signals) transmitted from wireless devices in order to classify authorized users. The most important requirement to develop an RFF method is the existence of a precise, robust, and extensive database of the emitted signals. In this context, this paper introduces a database consisting of Bluetooth (BT) signals collected at different sampling rates from 27 different smartphones (six manufacturers with several models for each). Firstly, the data acquisition system to create the database is described in detail. Then, the two well-known methods based on transient BT signals are experimentally tested by using the provided data to check their solidity. The results show that the created database may be useful for many researchers working on the development of the RFF of BT devices.Conference Object Citation - WoS: 10Citation - Scopus: 13A Multi-Agent System Model for Partner Selection Process in Virtual Enterprise(Elsevier Science Bv, 2014) Sadigh, B. Lotfi; Arikan, F.; Ozbayoglu, A. M.; Unver, H. O.; Kilic, S. E.; Lotfi Sadigh, B.Virtual Enterprise (VE) is a collaboration model between multiple business partners in a value chain. VE information system deals with highly dynamic information from heterogeneous data sources. In order to manage and store dynamic VE information in the database, an ontology based VE model has been developed. To select winner enterprises in VE, a Multi Agent System (MAS) has been developed. Communication and data transition among agents and system entities are based on defined rules in VE ontology model. One of the most important contributions of agents in VE system is in partner selection step of VE formation phase. In this step several agents with different goals and strategies are collaborating and competing each other to win the negotiation procedure or maximize the profit for their assigned enterprise. Different strategies are developed for the agents depending on their appetite for winning the auction against maximizing the profit. Several simulations were run and the results are stored. These results are fed into a neural network in order to predict which enterprise will win the auction and what will be the profit margin. The motivation is to provide a forecasting agent for the customers about the outcomes of the auctions so that they can plan ahead and take the necessary action. Early results indicate such simulated multi-agent VE formations can be used in real systems. A Multi-Agent System Model for Partner Selection Process in Virtual Enterprise (C) 2014 Published by Elsevier B.V.Article Citation - WoS: 13Citation - Scopus: 18A note on some coupled fixed-point theorems on G-metric spaces(Springeropen, 2012) Ding, Hui-Sheng; Karapinar, Erdal; Karapina, ErdalThe purpose of this paper is to extend some recent coupled fixed-point theorems in the context of G-metric space by essentially different and more natural way. We state some examples to illustrate our results.Article Citation - WoS: 3Citation - Scopus: 3A Note on the Generalized Matsumoto Relation(Tubitak Scientific & Technological Research Council Turkey, 2017) Dalyan, Elif; Medetogullari, Elif; Pamuk, MehmetcikWe give an elementary proof of a relation, first discovered in its full generality by Korkmaz, in the mapping class group of a closed orientable surface. Our proof uses only the well-known relations between Dehn twists.Article Citation - WoS: 2Citation - Scopus: 1A Close Examination of Ankara's Reinforced Concrete Buildings Designed and Constructed Between 1923 and 1938(Mdpi, 2023) Tunc, Gokhan; Tunc, Tanfer EminThe Republic of Turkey was established in 1923 out of the remains of the Ottoman Empire. Between 1923 and 1938, the Turkish republic underwent fifteen years of rapid expansion and growth, with Ankara as its new capital and Mustafa Kemal Ataturk (1881-1938) as its first president. During this period, reinforced concrete (RC) played a significant role in the construction of Ankara's public-use buildings. This study focuses on 57 of these structures, built either partially, or entirely, out of RC. The buildings are classified with respect to their duration, soil properties, foundation types, structural design details, construction types, materials and overall costs. In order to provide a better picture of the time period in which these buildings were designed and constructed, the technical, financial and political aspects of the projects, and the difficulties and challenges involved in their design and construction, are also discussed. Furthermore, this study outlines the impact of foreign engineers, construction workers, firms and the educational system on the development of civil engineering and use of RC in Turkey.Article Citation - WoS: 6Citation - Scopus: 6Revealing Defect Centers in Pbwo4 Single Crystals Using Thermally Stimulated Current Measurements(Aip Publishing, 2024) Isik, M.; Gasanly, N. M.The trap centers have a significant impact on the electronic properties of lead tungstate (PbWO4), suggesting their crucial role in optoelectronic applications. In the present study, we investigated and revealed the presence of shallow trap centers in PbWO4 crystals through the utilization of the thermally stimulated current (TSC) method. TSC experiments were performed in the 10-280 K range by applying a constant heating rate. The TSC spectrum showed the presence of a total of four peaks, two of which were overlapped. As a result of analyzing the TSC spectrum using the curve fit method, the activation energies of revealed centers were found as 0.03, 0.11, 0.16, and 0.35 eV. The trapping centers were associated with hole centers according to the comparison of TSC peak intensities recorded by illuminating the opposite polarity contacts. Our findings not only contribute to the fundamental understanding of the charge transport mechanisms in PbWO4 crystals but also hold great promise for enhancing their optoelectronic device performance. The identification and characterization of these shallow trap centers provide valuable insights for optimizing the design and fabrication of future optoelectronic devices based on PbWO4.
