Tidal wind mapping from observations of a meteor radar chain in December 2011

This article proposes a technique to map the tidal winds in the mesosphere and lower thermosphere (MLT) region from the observations of a four-station meteor radar chain located at middle- and low-latitudes along the 120 degrees E meridian in the Northern Hemisphere. A 1month dataset of the horizontal winds in the altitude range of 80-100km is observed during December 2011. We first decompose the tidal winds into mean, diurnal, semidiurnal, and terdiurnal components for each station. It is found that the diurnal/semidiurnal components dominate at the low-latitude/midlatitude stations. Their amplitudes increase at lower altitudes and then decrease at higher altitudes after reaching a peak in the MLT region. Hough functions of the classical tidal theory are then used to fit the latitudinal distribution of each decomposed component. The diurnal component is found to be dominated by the first symmetric (1, 1) mode. Yet for the semidiurnal and terdiurnal components, the corresponding dominant modes are the second symmetric modes (2, 4) and (3, 5), and considerable contributions are also from the first antisymmetric modes (2, 3), (3, 4) and second antisymmetric modes (2, 5), (3, 6). Based on the decomposed results, we further map the horizontal winds in the domains of latitude, altitude and local time. The mapped horizontal winds successfully reproduce the local time versus altitudinal distributions of the original observations at the four stations. Thus, we conclude that the meteor radar chain is useful to monitor and study the regional characteristics of the tidal winds in the MLT region

On Identity Tests for High Dimensional Data Using RMT

In this work, we redefined two important statistics, the CLRT test (Bai et.al., Ann. Stat. 37 (2009) 3822-3840) and the LW test (Ledoit and Wolf, Ann. Stat. 30 (2002) 1081-1102) on identity tests for high dimensional data using random matrix theories. Compared with existing CLRT and LW tests, the new tests can accommodate data which has unknown means and non-Gaussian distributions. Simulations demonstrate that the new tests have good properties in terms of size and power. What is more, even for Gaussian data, our new tests perform favorably in comparison to existing tests. Finally, we find the CLRT is more sensitive to eigenvalues less than 1 while the LW test has more advantages in relation to detecting eigenvalues larger than 1.Comment: 16 pages, 2 figures, 3 tables, To be published in the Journal of Multivariate Analysi

Optimal feature selection for sparse linear discriminant analysis and its applications in gene expression data

This work studies the theoretical rules of feature selection in linear discriminant analysis (LDA), and a new feature selection method is proposed for sparse linear discriminant analysis. An $l_1$ minimization method is used to select the important features from which the LDA will be constructed. The asymptotic results of this proposed two-stage LDA (TLDA) are studied, demonstrating that TLDA is an optimal classification rule whose convergence rate is the best compared to existing methods. The experiments on simulated and real datasets are consistent with the theoretical results and show that TLDA performs favorably in comparison with current methods. Overall, TLDA uses a lower minimum number of features or genes than other approaches to achieve a better result with a reduced misclassification rate.Comment: 20 pages, 3 figures, 5 tables, accepted by Computational Statistics and Data Analysi

Moon Imaging Technique and Experiments Based on Sanya Incoherent Scatter Radar

This article introduces the experiment design for Moon imaging based on Sanya incoherent scatter radar (SYISR) and algorithm research in data processing. The peak power of SYISR is 2 MW. The transmitted frequency used for Moon imaging experiments is 430 MHz. We conducted Moon imaging experiments using two types of waveforms, 13-bit Barker code, and linear frequency modulation (LFM) chirp. Considering both resolution and signal-to-noise ratio (SNR), the use of an LFM chirp with a bandwidth of 0.3 MHz and a pulsewidth of 2 ms can give higher SNR and resolution for Moon imaging using SYISR. Several key techniques were applied in the experiment design and data processing: 1) for the reliability of the imaging algorithm, the range-Doppler imaging algorithm commonly used in synthetic aperture imaging was applied; 2) to avoid the sidelobe effect of the 13-bit Barker code matched filter, a sidelobe-free filter was used; and 3) to mitigate the problem of “north–south ambiguity,” mosaic imaging of the Doppler northern and southern hemispheres of the nearside of the Moon was adopted. Two types of imaging results are obtained: mosaic images of the northern and southern hemispheres of the Moon and local regional images. The results demonstrate the feasibility and reliability of Moon imaging based on SYISR, which enables potential further lunar geology investigations in the future

Research on Traffic Signal Timing Method Based on Ant Colony Algorithm and Fuzzy Control Theory

The number of private cars has a blowout growth with the development of economics, which leads to the existing limited traffic resources cannot meet the normal traffic demand. The emergence of intelligent traffic has improved this phenomenon. Using intelligent traffic technology to conduct intersection vehicles can alleviate the congestion effectively. Traffic signal timing method plays an important role in intelligent traffic research. An independent intersection dynamic timing method combined with fuzzy control theory and improved ant colony algorithm is proposed in this paper. According to the characteristics of traffic flow distribution, the timing period is obtained with the improved webster algorithm. Through the optimal solution obtained by ant colony algorithm and the added delay of traffic signal calculated by fuzzy control method, the dynamic timing period of the traffic signal is obtained. The validity of the proposed method is proved by comparing with the original time period and the traditional algorithm

Concept for a Future Super Proton-Proton Collider

Following the discovery of the Higgs boson at LHC, new large colliders are being studied by the international high-energy community to explore Higgs physics in detail and new physics beyond the Standard Model. In China, a two-stage circular collider project CEPC-SPPC is proposed, with the first stage CEPC (Circular Electron Positron Collier, a so-called Higgs factory) focused on Higgs physics, and the second stage SPPC (Super Proton-Proton Collider) focused on new physics beyond the Standard Model. This paper discusses this second stage.Comment: 34 pages, 8 figures, 5 table

QDs-Cavity Approach to Controlled Quantum Teleportation of GHZ-Like State

The experimental scheme for controlled quantum teleportation of tripartite GHZ-like state is presented. With the entanglement generating through the interaction between the quantum dots in microcavities and a single photon, the controlled teleportation can be realized by virtue of Faraday rotation, single photon detection and electron spin orientation measurement. The success probability of the scheme can reach 1 if the cavities are switchable to choice the appropriate Faraday rotation angle. The scheme can be easily generalized to the teleportation of multipartite GHZ-like state