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Search Results: 1 - 10 of 80784 matches for " Lutao Liu "
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The Problems and the Development of Exploration of China’s Emergency Management System  [PDF]
Lutao Tian
Open Journal of Social Sciences (JSS) , 2018, DOI: 10.4236/jss.2018.612015
Abstract: In recent years, with the rapid development of China’s economy, the natural ecological environment has also been damaged. The disasters occur frequently, such as the Wenchuan Earthquake, the Southern Snowstorm and the Mangrove Typhoon, the stampede in Shanghai and the explosion in Tianjin. In this situation, we have to face the problem and deal with the variety of emergencies, because it would make people suffer enormous loss of life and property. Compared with the developed countries in the West, China’s emergency management system started late and the development is not enough. Therefore, our country must take action to construct an emergency management system to guarantee the safety of the development of economy, society and the people in the future. This paper first makes a brief analysis of the current situation and development of China’s emergency management system, and finally puts forward some reasonable suggestions.
Model Predictive Control of Piecewise Affine System with Constrained Input and Time Delay
Zhilin Liu,Lutao Liu,Jun Zhang,Xin Yuan
Abstract and Applied Analysis , 2013, DOI: 10.1155/2013/937274
Abstract: A model predictive control (MPC) is proposed for the piecewise affine (PWA) systems with constrained input and time delay. The corresponding operating region of the considered systems in state space is described as ellipsoid which can be characterized by a set of vector inequalities. And the constrained control input of the considered systems is solved in terms of linear matrix inequalities (LMIs). An MPC controller is designed that will move the PWA system with time delay from the current operating point to the desired one. Multiple objective functions are used to relax the monotonically decreasing condition of the Lyapunov function when the control algorithm switches from a quasi-infinite horizon to an infinite horizon strategy. The simulation results verify the effectiveness of the proposed method. It is shown that, based on LMI constraints, it is easy to get the MPC for the PWA systems with time delay. Moreover, it is suitable for practical application. 1. Introduction In engineering practice, there are many hybrid systems described by piecewise affine systems (PWA) which are composed of linear subsystems and convex polytopic regions. Hybrid systems are composed of discrete event dynamic systems and continuous time dynamic systems or discrete time dynamic systems, which interact with each other [1]. The hybrid system theory, which is proposed for the demand of the economic development, is the result of the development of computer science and control theory. Piecewise affine system is one of the most important branches of hybrid system [2]. It consists of some subsystems that integrate the logical and continuous dynamics by switching. Theoretically, any nonlinear system can be approximated as piecewise affine system [3, 4]. In [5], the PWA system is described as ellipsoid which can be characterized by a set of vector inequalities. In [6], the constraint of linear matrix inequalities (LMIs) is released. In terms of LMIs, the PWA system can be stabilized in Lyapunov theory. Model predictive control (MPC), also known as receding horizon control, is a popular technique for the control of dynamical systems, such as those encountered in chemical process control in the petrochemical, pulp and paper industries, and in industrial hot strip mill [7]. MPC is also a popular technique for the control of dynamical system subject to input and state constraints. At any time instant, MPC requires the online solution of an optimization problem to compute-optimal control inputs over a fixed number of future time instants, known as the finite horizon or quasi-infinite
Fast Estimation of Frequency and 2-D DOAs for Cylindrical Conformal Array Antenna Using State-Space and Propagator Method
Weijian Si;Liangtian Wan;Lutao Liu;Zuoxi Tian
PIER , 2013, DOI: 10.2528/PIER12121114
Abstract: The pattern of each element in conformal array has a different direction for the curvature of conformal carrier, which results in polarization diversity of conformal array antenna. Polarization parameters of incident signals are considered in snapshot data model in order to describe the polarization diversity of conformal array antenna. It is required that the polarization parameters and direction of arrival (DOA) of incident signals are estimated together. An integrated frequency and DOA estimation method is proposed in this paper for cylindrical conformal array antenna. The frequency estimation of signal source is obtained by constructing state-space matrix. Through well-designed configuration of elements on cylindrical carriers along with estimation of signal parameters via propagator method (PM), the decoupling scheme for DOA and polarization parameters is implemented. A novel parameter pairing method for frequency and DOA of multiple sources utilizing the interpolation technique is given, based on which the fast frequency-DOA estimation algorithm is developed. Effectiveness of the proposed method is demonstrated by simulation experimental results.
High Accuracy 2D-DOA Estimation for Conformal Array Using PARAFAC
Liangtian Wan,Weijian Si,Lutao Liu,Zuoxi Tian,Naixing Feng
International Journal of Antennas and Propagation , 2014, DOI: 10.1155/2014/394707
Abstract: Due to the polarization diversity (PD) of element patterns caused by the varying curvature of the conformal carrier, the conventional direction-of-arrival (DOA) estimation algorithms could not be applied to the conformal array. In order to describe the PD of conformal array, the polarization parameter is considered in the snapshot data model. The paramount difficulty for DOA estimation is the coupling between the angle information and polarization parameter. Based on the characteristic of the cylindrical conformal array, the decoupling between the polarization parameter and DOA can be realized with a specially designed array structure. 2D-DOA estimation of the cylindrical conformal array is accomplished via parallel factor analysis (PARAFAC) theory. To avoid parameter pairing problem, the algorithm forms a PARAFAC model of the covariance matrices in the covariance domain. The proposed algorithm can also be generalized to other conformal array structures and nonuniform noise scenario. Cramer-Rao bound (CRB) is derived and simulation results with the cylindrical conformal array are presented to verify the performance of the proposed algorithm. 1. Introduction Conformal arrays mounted on curved surfaces are commonly applied in various areas such as radar, sonar, and wireless communication [1]. The conformal antennas could fulfill specific aerodynamics, space-saving, elimination of random-induced bore-sight error, potential increase in available aperture, and so on [2, 3]. Most researches focus on the design of antenna configuration [4–6], the transform between the local and global coordinate [7–10], and the pattern synthesis of conformal array [11–15]. The conventional direction-of-arrival (DOA) estimation algorithms, for example, the multiple signal classification (MUSIC) [16] and the estimation of signal parameters via rotational invariance techniques (ESPRIT) [17], are not applicable due to the varying curvature of the conformal array. The “shadow effect” of the conformal array is caused by the metallic shelter, leading to the condition that not all elements have the ability to receive the signal. As a result of the incomplete steering vector, common DOA estimation algorithms cannot be used for conformal array. Recently, DOA estimation algorithms for conformal array have been proposed for high resolution [18–22]. With the help of fourth-order cumulant and ESPRIT algorithm, a blind DOA estimation algorithm is proposed in [18]. Based on the mathematical technique of geometric algebra, 2D-DOA and polarization parameter estimations are completed by
A Low Energy Consumption DOA Estimation Approach for Conformal Array in Ultra-Wideband
Liangtian Wan,Lutao Liu,Guangjie Han,Joel J. P. C. Rodrigues
Future Internet , 2013, DOI: 10.3390/fi5040611
Abstract: Most direction-of-arrival (DOA) estimation approaches for conformal array suffer from high computational complexity, which cause high energy loss for the direction finding system. Thus, a low energy consumption DOA estimation algorithm for conformal array antenna is proposed in this paper. The arbitrary baseline direction finding algorithm is extended to estimate DOA for a conformal array in ultra-wideband. The rotation comparison method is adopted to solve the ambiguity of direction finding. The virtual baseline approach is used to construct the virtual elements. Theoretically, the virtual elements can be extended in the space flexibility. Four elements (both actual and virtual elements) can be used to obtain a group of solutions. The space angle estimation can be obtained by using sub-array divided technique and matrix inversion method. The stability of the proposed algorithm can be guaranteed by averaging the angles obtained by different sub-arrays. Finally, the simulation results verify the effectiveness of the proposed method with high DOA estimation accuracy and relatively low computational complexity.
Hypoxia-Inducible MiR-210 Is an Independent Prognostic Factor and Contributes to Metastasis in Colorectal Cancer
Ailin Qu, Lutao Du, Yongmei Yang, Hui Liu, Juan Li, Lili Wang, Yimin Liu, Zhaogang Dong, Xin Zhang, Xiumei Jiang, Haiyan Wang, Zewu Li, Guixi Zheng, Chuanxin Wang
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0090952
Abstract: MicroRNA-210 (miR-210), the master hypoxamir, plays pleiotropic roles in certain cancers; however, its role in the development of human colorectal cancer remains unclear. Herein, we report that miR-210 is frequently up-regulated in colorectal cancer tissues, with high miR-210 expression significantly correlating with large tumor size, lymph node metastasis, advanced clinical stage and poor prognosis. Functionally, miR-210 overexpression promotes the migration and invasion of colorectal cancer cells. Furthermore, miR-210 can be induced by hypoxia and mediates the hypoxia-induced metastasis of colorectal cancer cells. In addition, vacuole membrane protein 1 (VMP1) is identified as the direct and functional target of miR-210. Thus, miR-210 is a useful biomarker for hypoxic tumor cells and a prognostic factor that plays an essential role in colorectal cancer metastasis.
The Potential Role of ORM2 in the Development of Colorectal Cancer
Xuhua Zhang, Zhiying Xiao, Xiaoyong Liu, Lutao Du, Lili Wang, Shun Wang, Ni Zheng, Guixi Zheng, Wei Li, Xin Zhang, Zhaogang Dong, Xuewei Zhuang, Chuanxin Wang
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0031868
Abstract: Colorectal cancer (CRC) is the third most common malignancy in the world. The risk of death is closely correlated to the stage of CRC at the time of primary diagnosis. Therefore, there is a compelling need for the identification of blood biomarkers that can enable early detection of CRC. We used a quantitative proteomic approach with isobaric labeling (iTRAQ) to examine changes in the plasma proteome of 10 patients with CRC compared to healthy volunteers. Enzyme-Linked Immunosorbnent Assay (ELISA) and Western blot were used for further validation. In our quantitative proteomics analysis, we detected 75 human plasma proteins with more than 95% confidence using iTRAQ labeling in conjunction with microQ-TOF MS. 9 up-regulated and 4 down-regulated proteins were observed in the CRC group. The ORM2 level in plasma was confirmed to be significantly elevated in patients suffering from CRC compared with the controls. ORM2 expression in CRC tissues was significantly increased compared with that in corresponding adjacent normal mucous tissues (P<0.001). ITRAQ together with Q-TOF/MS is a sensitive and reproducible technique of quantitative proteomics. Alteration in expression of ORM2 suggests that ORM2 could be used as a potential biomarker in the diagnosis of CRC.
Identification and Validation of Reference Genes for qPCR Detection of Serum microRNAs in Colorectal Adenocarcinoma Patients
Guixi Zheng, Haiyan Wang, Xin Zhang, Yongmei Yang, Lili Wang, Lutao Du, Wei Li, Juan Li, Ailin Qu, Yimin Liu, Chuanxin Wang
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0083025
Abstract: Serum microRNAs (miRNAs) have become a highlighted research hotspot, especially for their great potential as a novel promising non-invasive biomarker in cancer diagnosis. The most frequently used approach for serum miRNAs detection is quantitative real time polymerase chain reaction (qPCR). In order to obtain reliable qPCR data of miRNAs expression, the use of reference genes as endogenous control is undoubtly necessary. However, no systematic evaluation and validation of reference genes for normalizing qPCR analysis of serum miRNAs has been reported in colorectal adenocarcinoma. We firstly profiled pooled serum of colorectal adenocarcinoma, colorectal adenoma and healthy controls and selected a list of 13 miRNAs as candidate reference genes. U6 snRNA (U6) and above-mentioned 13 miRNAs were included in further confirmation by qPCR. As a result, 5 miRNAs (miR-151a-3p, miR-4446-3p, miR-221-3p, miR-93-5p and miR-3184-3p) were not detected in all samples and 2 miRNAs (miR-197-3p and miR-26a-5p) were relatively low with median Cq more than 35, and were excluded from further stability analysis. Then variable stability of other 6 miRNAs (miR-103b, miR-484, miR-16-5p, miR-3615, miR-18a-3p and miR-191-5p) and U6 were evaluated using two algorithms: geNorm and NormFinder which both identified miR-191-5p as the most stably expressed reference gene and selected miR-191-5p and U6 as the most stable pair of reference genes. After validating in an independent large cohorts and selecting miR-92a-3p as target miRNA to evaluate the effect of reference gene, we propose that combination of miR-191-5p and U6 could be used as reference genes for serum microRNAs qPCR data in colorectal adenocarcinoma, colorectal adenoma and healthy controls.
A Nonlinear Adaptive Beamforming Algorithm Based on Least Squares Support Vector Regression
Lutao Wang,Gang Jin,Zhengzhou Li,Hongbin Xu
Sensors , 2012, DOI: 10.3390/s120912424
Abstract: To overcome the performance degradation in the presence of steering vector mismatches, strict restrictions on the number of available snapshots, and numerous interferences, a novel beamforming approach based on nonlinear least-square support vector regression machine (LS-SVR) is derived in this paper. In this approach, the conventional linearly constrained minimum variance cost function used by minimum variance distortionless response (MVDR) beamformer is replaced by a squared-loss function to increase robustness in complex scenarios and provide additional control over the sidelobe level. Gaussian kernels are also used to obtain better generalization capacity. This novel approach has two highlights, one is a recursive regression procedure to estimate the weight vectors on real-time, the other is a sparse model with novelty criterion to reduce the final size of the beamformer. The analysis and simulation tests show that the proposed approach offers better noise suppression capability and achieve near optimal signal-to-interference-and-noise ratio (SINR) with a low computational burden, as compared to other recently proposed robust beamforming techniques.
Expression and clinical significance of miR-210 in the serum of patients with colorectal cancer

方茜, 曲爱林, 张欣, 杜鲁涛, 杨咏梅, 王传新
, QU Ailin, ZHANG Xin, DU Lutao, YANG Yongmei, WANG Chuanxin

- , 2015, DOI: 10.6040/j.issn.1671-7554.0.2015.060
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