İstanbul Bilgi Üniversitesi Kurumsal Akademik Arşivi
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Hyper-stable collective rankings
(Elsevier Science Bv, 2015) Laine, Jean
We 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.
Fresh state properties and compressive strength development of reactive MgO-based systems
(Elsevier, 2022) Taj, Khalilullah; Aktürk, Büşra; Ulukaya, Serhan
In 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.
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 Veysel
In 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.
A novel hybrid contouring control method for 3-DOF robotic manipulators
(Pergamon-Elsevier Science Ltd, 2016) Uzunovic, Tarik; Baran, Eray A.; Golubovic, Edin; Sabanovic, Asif
A 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.
Stereotype formation as trait aggregation
(Elsevier Science Bv, 2009) Can, Burak; Sanver, M. Remzi
We 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.
