Comparison of Reduction Methods for Peak-to-Average-Power-Ratio (PAPR) in MIMO-OFDM Systems with a New Approach

2nd International Conference on Computational and Experimental Science and Engineering (ICCESEN) -- OCT 14-19, 2015 -- Kemer, TURKEYtoren, murat/0000-0002-7012-7088WOS: 000384810700113This study is based on the comparison of the results of an analysis recommended for the peak-to-average-power-ratio (PAPR) reduction methods. This is one of the most significant problems in the multiple input-multiple output-orthogonal frequency division multiplexing (MIMO-OFDM) systems. the information in the signals of the wireless communication systems can be given in the frequency domain [S.H. Han, J.H. Lee, IEEE Signal Proc. Lett. 11, 887 (2004)]. of the methods applied for the PAPR reduction, which is one of the problems occurring in the frequency domain of the signals in MIMO-OFDM systems, the selective mapping (SLM) and the partial transmit sequences (PTS) are compared using a different approach. in the MIMO-OFDM systems, Fourier analysis is performed and the values of the signals on the frequency plane are taken although it is not clear which value of the signal at which time is taken [S.H. Han, J.H. Lee, IEEE Signal Proc. Lett. 11, 887 (2004)]. For the constant state of time, Fourier analysis approach is not appropriate for the detection of accurate frequency values. To solve this problem, a new wavelet transform-based (WT) analysis is recommended for the MIMO-OFDM systems with a new approach. It is shown that this analysis will be preferred instead of the Fourier analysis because of the optimization of the frequency-based temporary solutions of the signal. This approach of analysis is used along with the methods used for solving the PAPR problem in the MIMO-OFDM systems. Thereby, a comparison showing at which rate the methods for the solution of the problem contribute to solving the problem with this approach can be carried out. Numerical results show at which rate the methods with this approach can be carried out to contribute for solving the problem

Alteration of glassy volcanic rocks to Na-and Ca-smectites in the Neogene basin of Manisa, western Anatolia, Turkey

WOS: 000322350900008Alkali- and Ca-rich smectites occur in association with Neogene lacustrine sedimentary rocks and high-K calc-alkaline volcanic rocks with compositions ranging from andesite to rhyolite in western Anatolia (Turkey). Major clay occurrences are associated predominantly with the Foca and Akcakoy ignimbrites and with the ignimbrites within the Rahmanlar pyroclastics. Experimental studies indicate that the main clay minerals present are Na- and Ca-smectite and subordinate illite, associated with silica polymorphs, trace clinoptilolite and chlorite. The authigenic minerals formed by weathering and metasomatic reactions between hot volcanic material and lake water. Smectite was produced as a result of argillic alteration of the volcanic glass and feldspars of the ignimbrites, Rahmanlar pyroclastics and reworked volcaniclastic sediments through chemical weathering and dissolution-precipitation processes and formed as authigenic phases both in terrestrial and nearby shallow lacustrine environments under prevalent humid or semi-humid climate during the Neogene.Nigde University Scientific Research ProjectsThis study was funded by Nigde University Scientific Research Projects Unit (Project number: FEB 2005-07). The authors are indebted to David Bish (Indiana University, Bloomington, USA) for his contribution and kind help in XRD analyses and to O. Isik Ece (Istanbul Technical University, Turkey), Warren D. Huff (University of Cincinnati, USA), George Christidis (Technical University of Crete, Greece), Selahattin Kadir (Osmangazi University, Turkey), and Muazzez C. Karakaya (Selcuk University, Turkey) for their careful reading of the manuscript and comments. Their contributions and constructive criticisms significantly improved the manuscript

EVALUATION OF THE RELATIONSHIPS BETWEEN THE STRENGTH PROPERTIES OF HSC CONTAINING SF AND GP AT A LOW WATER-BINDER RATIO

WOS: 000369121700010In this paper, the effect of high strength concrete (HSC) manufactured with silica fume (SF) and ground pumice (GP) is investigated. Portland cement was replaced with SF, GP and combination of SF and GP up to 25%. 22 different concrete mixtures with these replacement ratios were produced by using 0.25 water-binder ratio. The ultrasound pulse velocity, compressive, splitting tensile and flexural strengths of these concretes were determined. The experimental results show that producing HSC is feasible with SF and GP. Besides, the experimental results indicate that SF and SF in combination with GP can enhance both the short-term and the long-term properties of concrete, whereas GP needs a comparatively longer time to obtain a suitable effect. The results are also supported by scanning electron microscope analysis. The optimum replacement ratios of SF and GP are found to be 15% and 5% of cement, respectively. The relationships between ultrasound pulse velocity, compressive, splitting tensile and flexural strengths are investigated by considering the effects of SF and GP

The influence of elevated temperature on strength and microstructure of high strength concrete containing ground pumice and metakaolin

A laboratory study is performed to evaluate the influence of elevated temperature on the strength and microstructural properties of high strength concretes (HSCs) containing ground pumice (GP), and blend of ground pumice and metakaolin (MK) mixture. Twelve different mixtures of HSCs containing GP and MM were produced, water-to-binder ratio was kept constant as 0.20. Hardened concrete specimens were exposed to 250 degrees C, 500 degrees C and 750 degrees C elevated temperatures increased with a heating rate of 5 degrees C/min. Ultrasound pulse velocity (U-pv), compressive strength (f(c)), flexural strength (f(fs)) and splitting tensile strength (f(sts)) values of concrete samples were measured on unheated control concrete and after air-cooling period of heated concrete. The crack formation and alterations in the matrix, interface and aggregate of HSCs were examined by X-ray diffraction (XRD), scanning electron microscope (SEM) and polarized light microscope (PLM) analyses. XRD, SEM and PLM analyses have shown that, increasing target temperature result with decrease in mechanical properties i.e. U-pv, f(c), f(fs) and f(sts) values. Elevated temperature also results with crack formation, and increasing target temperature caused more cracks. Alterations in the matrix, interface and aggregate were, also observed by these analyses. The experimental results indicate that concrete made with MK + GP blend together as a replacement of cement in mass basis behaved better than control concrete made with cement only, and concrete containing only GP as a cement replacement. (C) 2016 Elsevier Ltd. All rights reserved