Zeng F.,Chongqing Communication Institute
IEEE Communications Letters | Year: 2014
This letter discusses the construction of 16-quadratic-amplitude modulation (QAM) Golay complementary sequences of length N=2m. Based on the standard binary Golay-Davis-Jedwab (GDJ) complementary sequences (CSs), we present a method to convert the aforementioned GDJ CSs into the required sequences. The resultant sequences have the upper bounds 3.6N, 2.8N, 2N, 1.2N, and 0.4N of peak envelope powers, respectively, depending on the choices of their offsets. The numbers of the proposed sequences, corresponding to five upper bounds referred to above, are (24m-16)(m/2)2m+1, 128(m-1)(m/2)2m+1, (176m-160)(m/2)2m+1, 128(m-1)(m/2)2m+1, and (24m-16)(m/2)2m+1. Our sequences can be potentially applied to the QAM systems whose input signals are binary signals. © 1997-2012 IEEE.
Li Q.,Chongqing Communication Institute
Modern Tunnelling Technology | Year: 2014
The Nanhu tunnel goes beneath the Nanhu lake park in Nanning City, of which around 400 m section lies under the Nanhu lake. Construction of Nanhu tunnel is at high risk due to the poor geological conditions and high pressure of groundwater. To ensure safety during construction of foundation pit, based on the experiences of similar projects in past, it put forward a combined vertical water sealing by curtain grouting consisting of deep mixing piles (at upper slightly permeable layer) and high pressure jet grouting piles (at lower highly permeable layer) and dewatering by casing wells in foundation pit for the special geological condition in Nanning area to effectively control groundwater under high pressure during the period of construction. The soil nailing is applied as support of pit slope at the lake section and SMW method piles combining with inner support system are adopted as a support of foundation pit along lakeshore to ensure the construction safety. ©, 2015, Editorial Office of "Modern Tunnelling Technology". All right reserved.
Zeng F.,Chongqing Communication Institute
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences | Year: 2015
In Xu, Chen, and Liu's letter, two constructions producing perfect 8-QAM+/8-QAM sequences were given. We show that their constructions are equivalent to Zeng, et al.'s constructions under unit constant transform. Since the autocorrelation of a perfect sequence under unit constant transform is invariable, Xu, et al.'s constructions are the special case of Zeng, et al.'s constructions. © 2015 The Institute of Electronics, Information and Communication Engineers.
Liu H.,Chongqing Communication Institute |
Tao X.,Harbin Institute of Technology
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2013
A finite fault based hybrid source model of the great Wenchuan earthquake with magnitude 8.0 is built in this paper. The global parameters are mainly determined from the regional seismo-tectonics, structure of the crust, seismicity and a set of semi-experiential calibration laws. The local parameters consist of two groups. One is on asperity, the other one is on k square distribution. Both of them are generated from the truncated Normal distribution with mean and standard deviation values estimated by a set of calibration laws. 30 source models are presented finally.
Zhang G.,Chongqing University |
Tang B.,Chongqing University |
Tang G.,Chongqing Communication Institute
Measurement: Journal of the International Measurement Confederation | Year: 2012
An improved stochastic subspace identification algorithm is introduced to solve the low computational efficiency problem of the Data-driven stochastic subspace identification. Compared with the conventional algorithm, it needs much less cost of memory and computing time because it does not have a process of the QR decomposition of Hankel matrix. Model similarity index is proposed to measure the reliability of the modes obtained by the improved stochastic subspace identification. Furthermore, the stabilization diagram in combination with the modal similarity index is adopted to effectively indicate spurious modes resulting from noise and model redundancy. A criterion named the modal norm is introduced to indicate the dominating mode. A numerical example on the parameter estimation of a linear time-invariant system of 7 degrees of freedom and one experimental example on the parameter estimation of Chaotianmen bridge model in Chongqing are presented to demonstrate the efficacy of the method. © 2012 Elsevier Ltd. All rights reserved.