Fakülteler

Permanent URI for this communityhttps://hdl.handle.net/20.500.12469/28

Browse

Now showing 1 - 8 of 8

Citation - WoS: 5
Citation - Scopus: 7
Calculating Level Densities of Heavy Nuclei by the Shell Model Monte Carlo Method
(Academic Press Inc Elsevier Science, 2014) Alhassid, Yoram; Özen, Cem; Nakada, Hitoshi
The microscopic calculation of nuclear level densities in the presence of correlations is a difficult many-body problem. The shell model Monte Carlo method provides a powerful technique to carry out such calculations using the framework of the configuration-interaction shell model in spaces that are many orders of magnitude larger than spaces that can be treated by conventional methods. We present recent applications of the method to the calculation of level densities and their collective enhancement factors in heavy nuclei. The calculated level densities are in close agreement with experimental data.
Citation - WoS: 16
Citation - Scopus: 16
Detecting Structural Changes Using Wavelets
(Academic Press Inc Elsevier Science, 2015) Yazgan, M. Ege; Ozkan, Harun
We propose a powerful wavelet method to identify structural breaks in the mean of a process. If there is a structural change in the mean the sum of the squared scaling coefficients absorbs more variation leading to unequal weights for the variances of the wavelet and scaling coefficients. We use this feature of wavelets to design a statistical test for changes in the mean of an independently distributed process. We establish the limiting null distribution of our test and demonstrate that our test has good empirical size and substantive power relative to the existing alternatives especially for multiple breaks. (C) 2014 Elsevier Inc. All rights reserved.
Citation - WoS: 85
Citation - Scopus: 89
Electrical and Optical Percolations of Polystyrene Latex-Multiwalled Carbon Nanotube Composites
(Academic Press Inc Elsevier Science, 2010) Kara, Selim; Arda, Ertan; Dolastir, Fahrettin; Pekcan, Önder
Electrical conductivity and optical transmittance properties of polystyrene (PS)-multiwalled carbon nanotube (MWCNT) composite films were investigated. Composite films were prepared by mixing of various mass fractions of MWCNT in PS-water dispersions. After water evaporates powder composite films were annealed at 175 degrees C above the glass transition of PS for 20 min. Photon transmission and two point probe resistivity techniques were employed to determine the variations of the optical and the electrical properties of composites. Transmitted light intensity I(tr) and surface resistivity R(s) were monitored as a function of MWCNT mass fraction (M). It was observed that both the surface resistivity and the optical transparency were decreased by increasing the amount of MWCNT added to the polymeric system. Conductivity and optical results were interpreted according to the classical and site percolation theory respectively. The electrical (sigma) and the optical (op) percolation threshold values and critical exponents were calculated as M(sigma) = 1.8 wt.% M(op) = 0-0.13 wt.% and beta(sigma) = 2.25 beta(op) = 0.32 respectively. (C) 2010 Elsevier Inc. All rights reserved.
Citation - WoS: 27
Citation - Scopus: 27
Exploiting Heterogeneous Parallelism With the Heterogeneous Programming Library
(Academic Press Inc Elsevier Science, 2013) Vinas, Moises; Bozkuş, Zeki; Fraguela, Basilio B.
While recognition of the advantages of heterogeneous computing is steadily growing the issues of programmability and portability hinder its exploitation. The introduction of the OpenCL standard was a major step forward in that it provides code portability but its interface is even more complex than that of other approaches. In this paper we present the Heterogeneous Programming Library (HPL) which permits the development of heterogeneous applications addressing both portability and programmability while not sacrificing high performance. This is achieved by means of an embedded language and data types provided by the library with which generic computations to be run in heterogeneous devices can be expressed. A comparison in terms of programmability and performance with OpenCL shows that both approaches offer very similar performance while outlining the programmability advantages of HPL. (C) 2013 Elsevier Inc. All rights reserved.
Citation - WoS: 20
Citation - Scopus: 21
How People Can Become Persuaded by Weak Messages Presented by Credible Communicators: Not All Sleeper Effects Are Created Equal
(Academic Press Inc Elsevier Science, 2017) Albarracin, Dolores; Kumkale, Gökçe Tarcan; Vento, Patrick Poyner-Del
The sleeper effect has been proposed to describe temporal changes in persuasion for messages associated with noncredible sources. The present research introduces a new kind of sleeper effect denoting increases in persuasion for weak messages associated with credible sources. This effect of the source was hypothesized to derive from attending to the message source rather than the message arguments and reconstructing delayed attitudes primarily on the basis of the source information. Findings from three experiments revealed that when the focus of attention was the communicator there was a sleeper effect for the source. Specifically during the time between an immediate follow up and a delayed follow up persuasion increased when credible sources presented weak arguments. In contrast when the focus of attention was the message arguments a traditional sleeper effect emerged. That is persuasion increased when strong arguments were presented by a noncredible communicator. These effects were mediated by relative recall of arguments versus source attributes and replicated with different message topics and lengths of delay. (C) 2016 Published by Elsevier Inc.
Citation - WoS: 10
Citation - Scopus: 12
On Channel Estimation for Spatial Modulated Systems Over Time-Varying Channels
(Academic Press Inc Elsevier Science, 2015) Acar, Yusuf; Doğan, Hakan; Panayırcı, Erdal
Spatial Modulation (SM) has been proposed recently for multiple-input multiple-output (MIMO) systems to cope with the interchannel interference and to reduce the detection complexity as compared to the conventional MIMO systems. In SM system the data symbols are transmitted by a randomly selected active antenna of a MIMO transmitter to the receiver through a wireless channel. The information is carried both by the data symbol from any signal constellation such as M-ary phase shift keying (M-PSK) or M-ary quadrature amplitude modulation (M-QAM) by the index of the selected antenna. The channel estimation is a critical process at the receiver during the coherent detection of the transmitted symbol and the antenna index randomly selected. Recently the channel estimation of channel for SM systems has been investigated by the recursive least square (RLS) algorithm for only quasi-static fading channels. In this paper a novel channel estimation is proposed for SM systems in the presence of rapidly time-varying channels. The Bayesian mean square error (MSE) bound has been derived as a benchmark and the performance of the proposed approaches is studied in terms of MSE and bit-error rate (BER). Computer simulation results have confirmed that the proposed iterative channel estimation technique has significant BER/MSE performance advantages compared with existing channel estimation algorithm proposed earlier in the literature. (C) 2014 Elsevier Inc. All rights reserved.
Citation - WoS: 22
Citation - Scopus: 25
Secondhand Smoke in Waterpipe Tobacco Venues in Istanbul Moscow and Cairo
(Academic Press Inc Elsevier Science, 2019) Moon, Katherine A.; Magid, Hoda; Torrey, Christine; Rule, Ana M.; Ferguson, Jacqueline; Susan, Jolie; Sun, Zhuolu; Abubaker, Salahaddin; Levshin, Vladimir; Çarkoğlu, Aslı; Radwan, Ghada Nasr; El-Rabbat, Maha; Cohen, Joanna E.; Strickland, Paul; Navas-Acien, Ana; Breysse, Patrick N.
Objective: The prevalence of waterpipe tobacco smoking has risen in recent decades. Controlled studies suggest that waterpipe secondhand smoke (SHS) contains similar or greater quantities of toxicants than cigarette SHS which causes significant morbidity and mortality. Few studies have examined SHS from waterpipe tobacco in real-world settings. The purpose of this study was to quantify SHS exposure levels and describe the characteristics of waterpipe tobacco venues. Methods: In 2012-2014 we conducted cross-sectional surveys of 46 waterpipe tobacco venues (9 in Istanbul 17 in Moscow and 20 in Cairo). We administered venue questionnaires conducted venue observations and sampled indoor air particulate matter (PM2.5) (N=35) carbon monoxide (CO) (N=23) particle-bound polycyclic aromatic hydrocarbons (p-PAHs) (N=31) 4-methylnitrosamino)-1-(3-pyridy1)-1-butanone (NNK) (N-43) and air nicotine (N=46). Results: Venue characteristics and SHS concentrations were highly variable within and between cities. Overall we observed a mean (standard deviation (SD)) of 5 (5) waterpipe smokers and 5 (3) cigarette smokers per venue. The overall median (25th percentile 75th percentile) of venue mean air concentrations was 136 (82 213) mu/m(3) for PM2.5 3.9 (1.7 22) ppm for CO 68 (33 121) ng/m(3) for p-PAHs 1.0 (0.5 1.9) ng/m(3) for NNK and 5.3 (0.7 14) mu g/m(3) for nicotine. PM2.5 CO and p-PAHs concentrations were generally higher in venues with more waterpipe smokers and cigarette smokers although associations were not statistically significant. Conclusion: High concentrations of SHS constituents known to cause health effects indicate that indoor air quality in waterpipe tobacco venues may adversely affect the health of employees and customers. (C) 2015 Elsevier Inc. All rights reserved.
Citation - WoS: 9
Citation - Scopus: 9
Smoke-Free Turkey: Evaluation of Outdoor Areas of Public Places
(Academic Press Inc Elsevier Science, 2019) Kaplan, Bekir; Grau-Perez, Maria; Çarkoğlu, Aslı; Ergör, Gül; Hayran, Mutlu; Navas-Acien, Ana; Cohen, Joanna E.
Significance: Secondhand tobacco smoke (SHS) exposure is a major cause of morbidity and mortality around the world. The objective of this study was to evaluate the presence of smoking in outdoor areas of public places in three largest Turkish cities (Istanbul Ankara and Izmir). Method: For this cross-sectional observational study the Turkish Statistical Institute randomly selected 10 sampling points in each city. Around each sampling point fieldworkers visited the closest bars/nightclubs cafes government buildings hospitals restaurants schools shopping malls traditional coffee houses universities children's playgrounds parks and open markets. We observed smoking ashtrays and cigarette butts at the outdoor areas of public venues within the urban districts of each city. The fieldwork was conducted in April–May 2016. Results: 477 venues were observed covering 1017 outdoor locations in which 17737 people were observed. Smoking in outdoor areas ranged from 3.7% around schools to 90% in open markets. Ashtrays were almost ubiquitous in hospitals (95.6%) shopping malls (92.0%) and universities (90.9%). Cigarette butts were more often observed in open markets (100%) shopping malls (96%) universities (95.5%) and parks (93.3%). Smoking at outdoor areas around schools was significantly lower than around other venues. Conclusion: Smoking in outdoor areas was common in most public places in Turkey except schools. The current indoor SHS legislation should be extended to cover adjacent outdoor areas of public venues in order to effectively protect people from SHS exposure in Turkey. © 2019 The Authors

Browse

Browsing Fakülteler by browse.metadata.publisher "Academic Press Inc Elsevier Science"