中国科学院机构知识库网格系统: 检索

Retrieval of snow depth in Northeast China using FY-3B/MWRI passive microwave remote sensing data (EI CONFERENCE) 会议论文 OAI收割
Satellite Data Compression, Communications, and Processing VIII, August 12, 2012 - August 13, 2012, San Diego, CA, United states
Ren R.; Gu L.; Chen H.; Cao J.

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Comparing with optical remote sensing techniques passive remote sensing data have been proved to be effective for observing snowpack parameters such as snow depth and snow water equivalent which can penetrate snowpack without clouds interferences. The Microwave Radiation Imager (MWRI) loaded on the Chinese FengYun-3B (FY-3B) satellite is gradually used in the global environment research through November 2011. In this paper we proposed a snow depth retrieval algorithm to estimate snow depth in Northeast China using MWRI passive microwave remote sensing data. A decision tree method of snow identification was firstly designed to distinguish different snow cover conditions in order to eliminate other interference signals. After using the proposed decision tree method the processing results were further used to retrieve the snow depth in Northeast China. Finally the practical snow depth data and the MODIS data were collected for the accuracy assessment of the proposed snow depth retrieval method. The experimental results demonstrated that the RMSE of snow depth used the proposed method was approximately 3 cm in Northeast China. 2012 SPIE.

Analysis of zenith pass problem and tracking strategy design for roll-pitch seeker (EI CONFERENCE) 会议论文 OAI收割
作者: Jiang H.

收藏 | 浏览/下载：17/0 | 提交时间：2013/03/25

Roll-pitch seeker is currently applied in particular missiles. There is a stubborn problem called zenith pass problem while roll-pitch seeker is used. Analysis of the zenith pass problem which always results in loss of target is presented in this paper. Based on the analysis result tracking strategy is carried out to deal with zenith pass problem. To prove the validity of tracking strategy a practical roll-pitch seeker was accomplished. Model identification and common PID controllers for the physical roll-pitch seeker are taken on after that both disadvantages derived from zenith pass problem in tracking process and meliorated phenomenons by the tracking strategy are shown. It is concluded that the tracking strategy designed for solving the zenith pass problem is efficient. 2011 Elsevier Masson SAS. All rights reserved.

PID control of glucose concentration in subjects with type 1 diabetes based on a simplified model: An in silico trial (EI CONFERENCE) 会议论文 OAI收割
10th World Congress on Intelligent Control and Automation, WCICA 2012, July 6, 2012 - July 8, 2012, Beijing, China
作者: Yu L.

收藏 | 浏览/下载：17/0 | 提交时间：2013/03/25

An artificial pancreas system (APS) mimics the function of a real pancreas through monitoring a diabetic's blood glucose and administering the right dose of insulin via an automatic control loop. It is hailed as a promising cure of diabetes though this technology is still years away from commercial use due to a few technological bottlenecks. The simulation model of insulin-glucose metabolism of type 1 diabetes mellitus (T1DM) is an essential part of APS. In order to simplify the parameter identification task so that the model can be implemented electronically with ease this paper presents a simplified model based on Routh approximation model reduction method. The results show that the approximation error between the simplified model and the original model is so small that can be neglected. Based on the simplified model a PID controller is designed to maintain normoglycemia (90mg/dl) in subjects with T1DM. The in silico simulation results show that the glucose concentration is controlled well the risk of hyperglycemia and hypoglycemia is reduced a lot. This suggests that the simplified model describes the insulin-glucose metabolism process accurately and the PID control algorithm is well-suitable to guide the further development of an APS. 2012 IEEE.

Research on the identification for a nonlinear system (EI CONFERENCE) 会议论文 OAI收割
International Conference on Optical, Electronic Materials and Applications 2011, OEMA 2011, March 4, 2011 - March 6, 2011, Chongqing, China
作者: Liu J.; Jia P.; Liu J.; Liu J.

收藏 | 浏览/下载：23/0 | 提交时间：2013/03/25

The characteristic of the drift error of inertial platform is a high-order nonlinear dynamic system using the neural networks' abilities of universal approximation of differentiable trajectory and capturing system dynamic information this paper presents the drift error identifying project of inertial platform based on Elman networks structure. First the drift error model of inertial platform is established after selecting the input and output for network momentum and alterable speed algorithm is used to speed up the network convergence. On the basis of the algorithm the extended nonlinear node function in the hidden network does not only improve the learning speed of network but also satisfies the need of accuracy on system identification. Through the drift error data measured on inertial platform the training result shows that the scheme achieves satisfied identification results. (2011) Trans Tech Publications.

Electro-optical imaging system identification using pseudo-random binary pattern (EI CONFERENCE) 会议论文 OAI收割
2010 International Conference on Computer, Mechatronics, Control and Electronic Engineering, CMCE 2010, August 24, 2010 - August 26, 2010, Changchun, China
Le Y.; Jian W.; Jianzhong Z.; Qiang S.; Jianzhuo L.

收藏 | 浏览/下载：16/0 | 提交时间：2013/03/25

A method using pseudo-random binary pattern is developed for electro-optical imaging system identification. The imaging system is taken as a stable linear time-invariant and causal filter and its transfer function is measured through the pseudo-random binary sequence impulse responses identification. A digital mirror device (DMD) light projector is developed as the target generator and wavelet thresholding is used to denoise the captured image. Pre-filtering spectral estimation algorithm with adaptive parameter selection is also proposed for the identification process overcoming the challenge brought by the size limit derived from the optical isoplantic region. Simulations and experiments are presented to show the effectiveness of the proposed method.0-64. 2010 IEEE.

A fast and efficient multiple step algorithm of iris image quality assessment (EI CONFERENCE) 会议论文 OAI收割
2010 2nd International Conference on Future Computer and Communication, ICFCC 2010, May 21, 2010 - May 24, 2010, Wuhan, China
Shi C.; Jin L.

收藏 | 浏览/下载：12/0 | 提交时间：2013/03/25

Iris recognition is one of the most reliable methods of biometrics personal identification. Poor quality iris image will be rejected by recognition system which will result in the failure of recognition. Therefore iris image quality assessment is very essential to the iris recognition system. In this paper a multiple step algorithm of iris image quality assessment is proposed to distinguish two kinds of poor quality images i.e. defocus and occlusion. Experimental results show that the proposed algorithm is fast and efficient for iris image quality assessment. 2010 IEEE.

Adaptive segmentation algorithm for ship target under complex background (EI CONFERENCE) 会议论文 OAI收割
2010 3rd International Conference on Advanced Computer Theory and Engineering, ICACTE 2010, August 20, 2010 - August 22, 2010, Chengdu, China
Wang A.-B.; Wang C.-X.; Su W.-X.; Dong Y.-F.

收藏 | 浏览/下载：15/0 | 提交时间：2013/03/25

Segmentation of ship target under complex background has important research significance in long-range ship tracking and identification and an adaptive segmentation algorithm is proposed according to background images with different complexity. Local complexity of image is first calculated in this algorithm and then the original image is preprocessed with different de noising methods according to local complexity finally the image is binarized based on local complexity and the target is segmented. The experiment results indicate that the algorithm is adaptive and can meet the requirements of real-time processing which lays a foundation for ship target detection under complex background. 2010 IEEE.

High accuracy star image locating and imaging calibration for star sensor technology (EI CONFERENCE) 会议论文 OAI收割
6th International Symposium on Precision Engineering Measurements and Instrumentation, August 8, 2010 - August 11, 2010, Hangzhou, China
作者: Wang Y.; Wang Y.; Wang Y.; Wang Y.; Wang Y.

收藏 | 浏览/下载：12/0 | 提交时间：2013/03/25

Today aircraft attitude measurement technology plays an important role in an aircraft system because it can provide orientation for aircraft in action. Lately star sensor technology used in aircraft attitude measurement has become more and more popular because of its high accuracy light weight without attitude accumulation errors and other advantages. There are three main steps for star sensor to measure aircraft attitude star image locating star identification and attitude tracking. The latter two steps are based on the accuracy of star image locating. So it's critical to make efforts to advance the accuracy of star image locating. Some imaging errors such as spherical aberration or coma aberration also have negative effect on the accuracy of star image locating of which the effect is necessarily reduced as well. At the beginning of this article the structure of star sensor hardware is introduced. Secondly three methods for star image locating are described specifically which are traditional centroid method Gauss quadric fitting method and improved Gauss quadric fitting method. Subsequently an imaging calibration method is described for the purpose of reducing the effect of imaging errors. Finally the experiment shows that the accuracy of the star sensor is 2-arc-second. 2010 SPIE.

The research on the automatic measurement of frequency characteristics of opto-electronic platform (EI CONFERENCE) 会议论文 OAI收割
2010 International Conference on Computer, Mechatronics, Control and Electronic Engineering, CMCE 2010, August 24, 2010 - August 26, 2010, Changchun, China
作者: Liu H.; Liu H.; Chen J.; Liu H.

收藏 | 浏览/下载：15/0 | 提交时间：2013/03/25

A new frequency characteristic test method is proposed based on the digitization characteristics of optoelectronic platform servo system. First a digital processing controller is used to automatically test the entire process and tested data are uploaded to a PC through CAN-bus and then the tested data are transferred into accurate transfer function with the Levy method. Here we discuss the testing steps the data processing the extraction the Bode diagram plotting and the model identification in detail. The corresponding experiments are carried out and the results show that the method is simple with the features of high efficiency high precision and engineering feasibility. 2010 IEEE.

Model identification and closed-loop confirmation for opto-electronic platform of seeker (EI CONFERENCE) 会议论文 OAI收割
2010 2nd International Conference on Industrial Mechatronics and Automation, ICIMA 2010, May 30, 2010 - May 31, 2010, Wuhan, China
作者: Liu H.; Zhang J.; Zhang J.; Zhang J.; Chen J.

收藏 | 浏览/下载：27/0 | 提交时间：2013/03/25

A mathematical model of seeker opto-electronic platform is the basis for researching performance designing a servo control system and simulating. Focusing on high frequencies of mechanical resonant restriction of gimbaled axis rotation a new model identification method was proposed under the pseudo-random invert-M-sequences. The testing signal data acquisition the calculating of frequency response and least square identification were investigated. The realized steps are explicitly illustrated and the testing example is given in this paper the results confirm that the proposed method is effective and practical. 2010 IEEE.