167 research outputs found
Get the permission for paper publication--UTiris--Author Siming Zheng--2019-11-10
No full textRequesting the permission for paper publication.Author Siming ZhengWritten date: 2019-11-10</div
An Efficient Implementation of Lattice Staggered Multicarrier Faster-Than-Nyquist Signaling
No full textIn this letter, we investigate the lattice staggered multicarrier faster-than-Nyquist (MFTN) signaling. Specifically, we consider the time-frequency packing and optimal hexagonal lattice over additive white Gaussian noise channels. First, an efficient implementation of the lattice staggered MFTN based on the fast Fourier transform algorithm is proposed, and we show that the modulation and demodulation complexity could be substantially reduced. Furthermore, we consider, at the receiver, a low-complexity symbol-by-symbol detector. Our practical spectral efficiency and bit-error-rate performance investigation demonstrate that the MFTN with optimal hexagonal lattice outperforms the conventional rectangular lattice
Optimal multicarrier faster-than-Nyquist signaling under symbol-by-symbol detection
No full textWe consider the multicarrier faster-than-Nyquist (MFTN) signaling under low complexity symbol-by-symbol detection, where the lattice structure and time-frequency spacing play key roles in determining the system performance. Specifically, the energy of intersymbol interference (ISI) and intercarrier interference (ICI) introduced by time-frequency packing is taken as a figure of merit. In this regard, we firstly prove the asymptotical equivalence of the hexagonal MFTN and conventional rectangular MFTN signaling systems when the time packing factor is small enough, and we also reveal the potential benefit of hexagonal MFTN with respect to conventional rectangular MFTN for moderate time-frequency spacing. Then, an optimal MFTN signaling scheme under the given signaling efficiency is proposed. By jointly optimizing the lattice structure and time-frequency spacing to minimize the interference energy, we show that the optimal time-frequency spacing can be accurately obtained with substantially reduced complexity than conventional exhaustive search scheme. Finally, we demonstrate that there is a good match between minimizing the interference energy and maximizing the achievable spectral efficiency, which is also considered to be an important figure for MFTN signaling system. Our theoretical analysis and numerical results validate that the proposed scheme outperforms conventional MFTN signaling system
Author Siming Zheng-Experimental Iris Images--IRIS V.1
No full textUniversity of Tehran IRIS (UTIRIS) image repository is the first iris biometric databank registered in two distinct sessions of Visible Wavelength (VW) and Near InfraRed (NIR) imaging during 24-27th of June 2007
Author-SIMING_ZHENG-20190923--UNIVERSITY OF TEHRAN IRIS IMAGE REPOSITORY--UTIRIS-RGB Original Images
No full textThere are 806 RGB eye(iris) images
Author--SIMING_ZHENG-20190923--UNIVERSITY OF TEHRAN IRIS IMAGE REPOSITORY--UTIRIS-Original RGB Images
No full textThis is the original RGB UTIRIS dataset
Mechanism and Influencing Factors of Iron Nuggets Forming in Rotary Hearth Furnace Process at Lower Temperature
No full text
In order to improve the efficiency of slag and iron separation, a new idea of "the separation of slag (solid state) and iron (molten state) in rotary hearth furnace process at lower temperature" is put forward. In this paper, the forming process of iron nuggets has been investigated. Based on those results, the forming mechanisms and influencing factors of iron nugget at low temperature are discussed experimentally using an electric resistance furnace simulating a rotary hearth furnace process. Results show that the reduction of iron ore, carburization of reduced iron, and the composition and quantity of slag are very important for producing iron nuggets at lower temperature. Reduction reaction of carbon-containing pellets is mainly at 1273 K and 1473 K (1000 A degrees C and 1200 A degrees C). When the temperature is above 1473 K (1200 A degrees C), the metallization rate of carbon-containing pellets exceeds 93 pct, and the reduction reaction is substantially complete. Direct carburization is the main method for carburization of reduced iron. This reaction occurs above 1273 K (1000 A degrees C), with carburization degree increasing greatly at 1473 K and 1573 K (1200 A degrees C and 1300 A degrees C) after particular holding times. Besides, to achieve the "slag (solid state) and iron (molten state) separation," the melting point of the slag phase should be increased. Slag (solid state) and iron (molten state) separation can be achieved below 1573 K (1300 A degrees C), and when the holding time is 20 minutes, C/O is 0.7, basicity is less than 0.5 and a Na2CO3 level of 3 pct, the recovery rate of iron can reach 90 pct, with a proportion of iron nuggets more than 3.15 mm of nearly 90 pct. This study can provide theoretical and technical basis for iron nugget production.</p
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