Web of Science Indexed Publications
Bu koleksiyon için kalıcı URI
Güncel Gönderiler
Öğe Hyper-stable collective rankings(Elsevier Science Bv, 2015) Laine, JeanWe introduce a new consistency property for social welfare functions (SWF), called hyper-stability. An SWF is hyper-stable if at any profile over finitely many alternatives where a weak order R is chosen, there exists a profile of linear orders over linear orders, called hyper-profile, at which only linearizations of R are ranked first by the SWF. Profiles induce hyper-profiles according to some minimal compatibility conditions. We provide sufficient conditions for hyper-stability, and we investigate hyper-stability for several Condorcet SWFs. An important conclusion is that there are non-dictatorial hyper-stable SWFs. (C) 2015 Elsevier B.V. All rights reserved.Öğe Fresh state properties and compressive strength development of reactive MgO-based systems(Elsevier, 2022) Taj, Khalilullah; Aktürk, Büşra; Ulukaya, SerhanIn this study, flowability, setting time, and strength gain of mortars containing reactive magnesium oxide cement (RMC) and a combination of micro-silica (MS), nano-silica (NS), slag, and fly ash (FA) as precur-sors without employing accelerated carbonation have been investigated. To increase the flowability and hydration degree, sodium hexametaphosphate (SHMP) was incorporated. The series containing RMC and MS simultaneously, had the greatest 3-day compressive strength value of about 25 MPa, whereas further strength gains in all the mixtures until the 7th day was minimal, which establishes that strength gains were due to hydration degree, not carbonation. RMC and MS simultaneously in a series, a combination of extremely high fineness materials dropped the flowability; the presence of slag and FA, on the other hand, enhanced it. The inclusion of NS in the mix didn't demonstrate a perceptible change in any of the properties measured in this study; its inertness could be attributed to the unsuitable dispersion method. Setting time of reference mix was the shortest, which was in conformity with its fast initial strength gain. Replacement of RMC with any other binder extended both the initial and final setting time. It was hypothesized that a major difference in this study is the use of SHMP as a dispersant and hydration agent. The outcomes of this study confirm that RMC can be a potential binder material to be used in mor-tar productions.Copyright (c) 2022 Elsevier Ltd. All rights reserved.Selection and peer-review under responsibility of the scientific committee of the International Confer-ence on Advances in Construction Materials and Structures.Öğe Effect of intrinsic polymer properties on the photo sensitive organic field-effect transistors (Photo-OFETs)(Elsevier, 2016) Kosemen, Zuhal Alpaslan; Kosemen, Arif; Ozturk, Sadullah; Canimkurbey, Betul; San, Sait Eren; Yerli, Yusuf; Tunc, Ali VeyselIn this work, we have demonstrated how the intrinsic properties of a conjugated polymer can influence the electro-optical characteristics of photo sensitive organic field - effect transistors (Photo-OFETs). Photo-OFETs fabricated with three batches of poly[2-methoxy,5-(3',7'-dimethyl-octyloxy)]-p-phenylene vinylene (MDMO-PPV) were investigated in the scope of our work. Photo-OFETs were fabricated with the polymers, than electrically and electro-optically characterized. It was observed that the channel current and the field-effect mobility increase with increasing polymer molecular weight. Interestingly, the electro-optical characteristics and photo switching properties of the transistors were found to depend on the polydispersity (PDI) of the polymer as well. These results are explained in terms of influences of chain packing, ordering and trap density on the FET switching properties and transistor parameters. (C) 2016 Elsevier B.V. All tights reserved.Öğe A novel hybrid contouring control method for 3-DOF robotic manipulators(Pergamon-Elsevier Science Ltd, 2016) Uzunovic, Tarik; Baran, Eray A.; Golubovic, Edin; Sabanovic, AsifA novel controller for three-dimensional contouring control of three-degrees-of-freedom (3-DOF) robotic manipulators is presented in this paper. The proposed controller comprises of an independent joint controller, designed in the configuration space, and a sliding mode controller that enforces desired dynamics for the tracking error projections to the Frenet-Serret frame. Therefore, the presented controller has a hybrid structure and it is named as hybrid contouring controller. In this paper, contour tracking with constant magnitude tangential velocity is discussed. Reference trajectory is generated using the time based spline approximation in order to provide a smooth reference path. The proposed hybrid contouring controller was experimentally compared with the independent joint controller that is designed in the acceleration control framework with disturbance observer. Experimental results, undertaken on a delta robot, showed that hybrid contouring controller outperforms independent joint control architecture. (C) 2016 Elsevier Ltd. All rights reserved.Öğe Stereotype formation as trait aggregation(Elsevier Science Bv, 2009) Can, Burak; Sanver, M. RemziWe propose an aggregation model which explains stereotype formation under the attribution hypothesis. We show, under very mild axioms, that an observer can be thought of perceiving a group in terms of her subjective opinion about the representativeness of subgroups, as well as a possible prejudice she might have. (C) 2009 Elsevier B.V. All rights reserved.Öğe Characterization of the core in full domain marriage problems(Elsevier Science Bv, 2014) Nizamogullari, Duygu; Ozkal-Sanver, IpekIn this paper, we study the core of two-sided, one-to-one matching problems. First, in a model in which agents have strict preferences over their potential mates and are allowed to remain single, we characterize the core as the unique solution that satisfies individual rationality, Pareto optimality, gender fairness, consistency, and converse consistency. Next, in a model that relaxes the constraint that agents have strict preferences over their potential mates, we show that no solution exists that satisfies Pareto optimality, anonymity, and converse consistency. In this full domain, we characterize the core by individual rationality, weak Pareto optimality, monotonicity, gender fairness, consistency, and converse consistency. (C) 2014 Elsevier B.V. All rights reserved.Öğe Karachay-Balkar relative clauses: Implications for a special type of genitive/nominative alternation(Elsevier, 2020) Gurer, AsliTaking reduced relative clauses as the basis of comparison, this study investigates Karachay-Balkar non-subject relative clauses with two different patterns. The subject in the modifier clause can bear the genitive case in the presence of agreement morphology on the head noun, or the nominative case in the absence of agreement morphology. Based on binding and adverbial placement tests, the current study suggests that (i) Karachay-Balkar relative clause patterns with genitive or nominative subjects are deficient in the absence of CP and TP; (ii) in the absence of TP, temporal interpretation is a secondary effect of AspP; (iii) the genitive subject moves into the DP domain to check the definiteness feature; (iv) the genitive pattern is preferred when the referents of the genitive construction and the head noun are shared by the speaker and the hearer; and (v) in the absence of the definiteness feature and CP/TP, the nominative case is licensed as the default case. This study shows that Karachay-Balkar relative clauses are reduced with respect to the absence of CP/TP. However, the size of the structure does not differ in genitive and nominative patterns, and the patterns are not in free variation as a syntax-semantic interface is at play. (C) 2020 Elsevier B.V. All rights reserved.Öğe Implementing matching rules by type pretension mechanisms(Elsevier Science Bv, 2005) Özkal-Sanver, I; Sanver, MRWe consider a two-sided matching model where agents' preferences are a function of the types of their potential mates. Matching rules are manipulated by type misrepresentation. We explore the implementability of the G-core in G-Strong Nash Equilibria. Although direct type pretension mechanisms rule out bad equilibria, the existence of equilibrium cannot be generally guaranteed. However, taking G as the discrete partition, the individually rational matching correspondence is partially implementable in Nash equilibria. On the other hand, incorporating a certain degree of hypocrisy in the mechanism, i.e., allowing agents to pretend different types to different potential mates, ensures the full implementability of the G-core in G-Strong Nash Equilibria. (c) 2005 Elsevier B.V. All rights reserved.Öğe A note on gender fairness in matching problems(Elsevier, 2004) Özkal-Sanver, IWe introduce the gender fairness (GF) axiom. We show that the core is the minimal solution which satisfies Pareto optimality (PO), converse consistency (CC), and gender fairness. (C) 2003 Elsevier B.V. All rights reserved.Öğe The need for a regional framework for marine scientific research in the Black Sea and Mediterranean Sea(Elsevier Science Bv, 2014) Oral, NiluferOne of the important contributions of the 1982 United Nations Law of the Sea Convention (UNCLOS) is Part XIII on Marine Scientific Research (MSR). UNCLOS recognizes the general rule that all states have the right to conduct MSR subject to rights and duties of other states under the convention and in addition, the obligation to promote and facilitate MSR. (C) 2014 Elsevier B.V. All rights reserved.Öğe Impossibilities for roommate problems(Elsevier, 2010) Ozkal-Sanver, IpekWe establish three impossibility results for roommate problems. First, no single valued solution is Pareto optimal and anonymous. Next, no solution satisfies Pareto optimality, anonymity and converse consistency. Finally, no pseudo-refinement of the core satisfies consistency (C) 2010 Elsevier B.V. All rights reservedÖğe Forecasting electricity consumption of OECD countries: A global machine learning modeling approach(Elsevier Sci Ltd, 2021) Sen, Doruk; Tunc, K. M. Murat; Gunay, M. ErdemElectricity is a critical utility for social growth. Accurate estimation of its consumption plays a vital role in economic development. A database that included past electricity consumption data from all OECD countries was prepared. Since national trends may be transferable from one country to another, the entire database was modeled and simulated via machine learning techniques to forecast the energy consumption of each country. Understanding similarities among the profiles of different countries could increase predictive accuracy and improve associated public policies.Öğe On the manipulability of voting rules: The case of 4 and 5 alternatives(Elsevier Science Bv, 2012) Aleskerov, Fuad; Karabekyan, Daniel; Sanver, M. Remzi; Yakuba, VyacheslavBy extending manipulability indices defined for single-valued social choice rules to the multi-valued case, we explore the degree of manipulability of seven multi-valued social choice rules. Our analysis is based on computational experiments. (C) 2011 Elsevier B.V. All rights reserved.Öğe A characterization of superdictatorial domains for strategy-proof social choice functions(Elsevier Science Bv, 2007) Sanver, M. RemziA domain D is dictatorial iff there exists no surjective, strategy-proof and non-dictatorial social choice function defined over D. A dictatorial domain D is superdictatorial iff every superdomain of D is also dictatorial. The existence of dictatorial but not superdictatorial domains being known, we show that a dictatorial domain D is superdictatorial iff every alternative is ranked at the top by some ordering in D. (C) 2007 Elsevier B.V. All rights reserved.Öğe The Determination of Patient Learning Needs After Day Surgery: A Cross- Sectional Study(Elsevier Science Inc, 2023) Ustundag, Hulya; Gul, Asiye; Ozkaya, BirgulPurpose: This study was conducted to investigate the care perception and learning needs of patients undergo-ing day surgery. Design: A descriptive and cross-sectional model was used. Methods: The study was conducted with 234 patients who underwent day surgery in a general surgery clinic of a university hospital. Data were collected using a sociodemographic characteristics form, the Patient Perception of Hospital Experience with Nursing Scale (PPHEN) and the Patient Learning Needs Scale (PLNS). Findings: The PPHEN mean score was 67.99 +/- 11.98 and the PLNS total score was 211.15 +/- 38.49. The sub-scales showed that the highest scores were 38.47 +/- 6.93 for activities of life, while the lowest score was 20.60 +/- 4.23 for feelings related to condition. There was a statistically significant negative correlation in the PPHEN and PLNS subscales in terms of medications, activities of living, treatment, and complications. There was no statistically significant relationship between the demographic data of the patients (age, gender, and educational status). Conclusions: This study demonstrated that patients had high information needs and greater concerns, partic-ularly about activities of life. Nurses should be aware of the importance of identifying high learning needs to increase the level of satisfaction with nursing care in day surgery patients. (c) 2022 American Society of PeriAnesthesia Nurses. Published by Elsevier Inc. All rights reserved.Öğe Reliability considerations of a fuel cell backup power system for telecom applications(Elsevier Science Bv, 2016) Serincan, Mustafa FazilA commercial fuel cell backup power unit is tested in real life operating conditions at a base station of a Turkish telecom operator. The fuel cell system responds to 256 of 260 electric,power outages successfully, providing the required power to the base station. Reliability of the fuel cell backup power unit is found to be 98.5% at the system level. On the other hand, a qualitative reliability analysis at the component level is carried out. Implications of the power management algorithm on reliability is discussed. Moreover, integration of the backup power unit to the base station ecosystem is reviewed in the context of reliability. Impact of inverter design on the stability of the output power is outlined. Significant current harmonics are encountered when a generic inverter is used. However, ripples are attenuated significantly when a custom design inverter is used. Further, fault conditions are considered for real world case studies such as running out of hydrogen, a malfunction in the system, or an unprecedented operating scheme. Some design guidelines are suggested for hybridization of the backup power unit for an uninterrupted operation. (C) 2016 Elsevier B.V. All rights reserved.Öğe A new analysis methodology for estimating the eigenfrequencies of systems with high modal damping(Academic Press Ltd- Elsevier Science Ltd, 2016) Ozbek, Muammer; Rixen, Daniel J.Contemporary system identification algorithms are well proven to provide accurate eigenfrequency estimates in analyzing the systems with low modal damping. Since most engineering structures usually have low damping ratios the corresponding response characteristics can easily be obtained by conventional methods. Indeed, these modes can be extracted by using relatively short measurement durations (150-200 cycles of the lowest frequency included in the data block). However, some specific applications such as analyzing the in-operation vibration behavior of MW scale large wind turbines also require an accurate estimation of the modes with high damping. For a rotating wind turbine, some important turbine modes (e.g. flapwise rotor modes) have very high aeroelastic damping, which make them very difficult (if not impossible) to be detected. Extracting these high damping modes is a challenging task for almost all system identification techniques that are currently in use. In this work, a new method, which is based on Natural Excitation Technique (NExT), is proposed as an alternative approach for extracting the eigenfrequencies of high damping modes in an efficient way. NExT is a well established experimental dynamic analysis tool which was specifically developed to extract the dynamic characteristics of wind turbines in the early 90s. However, during the analyses it was observed that conventional NExT algorithm requires analyzing very long measurement durations (4500-5000 cycles) to be able to estimate the high damping modes accurately. A new method proposed in this work enables the eigenfrequencies of high damping modes to be estimated by using data series which are approximately 30 times shorter (around 150 cycles) than those required for a standard NExT algorithm. (C) 2015 Elsevier Ltd. All rights reserved.Öğe Fuzzy rule-based demand forecasting for dynamic pricing of a maritime company(Elsevier Science Bv, 2014) Cogun, Ozlem; Ekinci, Yeliz; Yanik, SedaIn this study, the pricing problem of a transportation service provider company is considered. Our goal is to find optimal prices by using probabilistic dynamic programming. A fuzzy IF-THEN-rule based system is used to identify the demand levels under different prices and other characteristics of the journey. The results obtained by optimal price policies show that the revenue increases by applying dynamic pricing policy instead of fixed pricing. Thus, the diversification of pricing policies under different conditions is beneficial for the company. (C) 2014 Elsevier B.V. All rights reserved.Öğe Is B-Flow USG superior to Color Doppler USG for evaluating blood flow patterns in ovarian torsion?(W B Saunders Co-Elsevier Inc, 2015) Hancerliogullari, Kadir Oymen; Soyer, Tutku; Tosun, Alptekin; Hancerliogullari, GulsahObjective: Ovarian torsion is an uncommon gynecological emergency that most often affects women of reproductive age. Its signs and symptoms are similar to those of other abdominal conditions, which make its differential diagnosis challenging. Color Doppler (Doppler USG) and B-flow ultrasonography (B-flow USG) are used for the differential diagnosis of ovarian torsion, and in this study, we aimed to evaluate these two techniques, validate B-flow USG as the gold standard non invasive diagnostic tool in the early phase of an ovarian torsion, and show that the B-flow USG is superior to the color Doppler USG. Materials and methods: Sixteen rabbits of the same age and weight were separated into 2 subgroups of 8. In Group I (shamgroup), right ovaries were fixated, and in Group II (torsion group), right ovaries underwent 720 degrees torsion in a counterclockwise direction. At 1 h and 2 h of ischemia, both ovaries were measured by the two techniques, and an additional measurement was taken at 24 h to determine any changes in the left ovary due to the right ovary ischemia. Volume flow, peak systolic velocity (PSV), end diastolic velocity (EDV), resistive index (RI) and pulsatility index (PI) measurements were taken both with color Doppler USG (using a 12 MHz linear probe, General Electric Medical Systems Logic 7, Milwaukee, USA) and with B-flow USG. Results: The right Doppler RI and PI values at 1 h were significantly higher than the right B-flow values (p < 0.05). The difference between the left B-flow RI and PI values and the left Doppler values at 1 h was not significant (p > 0.05), nor was the difference between the right B-flow RI value at 2 h and the right Doppler RI value at 2 h (p > 0.05). The right B-flow PI value at 2 h was statistically different from the right Doppler PI value at 2 h (p < 0.05), although the differences between the left B-flow RI and PI values at 1 h and 2 h and the left Doppler RI and PI values were not (p > 0.05). However, there was a significant difference between the RI values at 24 h (p < 0.05). Conclusions: In this study, the decrease in blood reperfusion at 1 h measured by B-flow USG was apparently higher than that measured by Doppler USG. However, by the end of 2 h, the measurements were equal (see Fig. 3 and 4). In conclusion, B-flow USG reveals the decrease in the blood flow more distinctly in the early phase. Moreover, B-flow Doppler USG is more reliable and advantageous than color Doppler USG because it provides a more accurate preoperative evaluation of the unilateral and contralateral preoperative adnexial structures, and allows for a better assessment of blood flow in the ovarian torsion. (C) 2015 Elsevier Inc. All rights reserved.Öğe May robots be held responsible for service failure and recovery? The role of robot service provider agents' human-likeness(Elsevier Sci Ltd, 2023) Arikan, Esra; Altinigne, Nesenur; Kuzgun, Ebru; Okan, MehmetThis research investigates how consumers attribute service failure and recovery responsibilities and respond to them differently based on the service provider agent type (human, humanoid, and non-humanoid robot). Two experiments show that, first, consumers attribute more service failure responsibility to the firm when the agent is less human-like. Second, they attribute more recovery responsibility to the agent and less to the firm when those agents are human, rather than robots. Third, failure (recovery) attribution to the firm reduces (enhances) consumer forgiveness and satisfaction. This study identifies the impact of human-likeness and humanness on responsibility attribution processes in interaction with robotic and human agents.
