中国科学院机构知识库网格系统: 检索

On accelerating a multilevel correction adaptive finite element method for Kohn-Sham equation 期刊论文 OAI收割
JOURNAL OF COMPUTATIONAL PHYSICS, 2023, 卷号: 472, 页码: 22
作者: Hu, Guanghui; Xie, Hehu; Xu, Fei

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Kohn-Sham equation Multilevel correction method Finite element method Separately handing nonlinear terms Parallel computing

Communication synchronization in wireless optical link (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Control Engineering and Communication Technology, ICCECT 2012, December 7, 2012 - December 9, 2012, Shenyang, Liaoning, China
作者: Guo J.; Guo J.; Wang H.; Wang H.; Wang H.

收藏 | 浏览/下载：31/0 | 提交时间：2013/03/25

An FPGA based transceiving synchronization method is demonstrated for Free Space Optical (FSO) communication system which is discussed separately as the transmitting protocol and the receiving protocol. During the discussion of these two parts the co-operation of them is also discussed. The transmitting protocol interfaces the outer input data with a parallel port buffers the input data encodes the input data stream serializes the parallel data and outputs the serialized data. It also has an output management unit to manage the activity of each part of the transmitting protocol. The receiving protocol filters and synchronizes the input serial data stream parallels the serial data stream decodes the input data checks received error handles transmission exception and interfaces the outer receiver with a parallel port. The entire transceiving protocol could be programmed into a single FPGA chip to improve system integrity and reduce the system cost. The presented protocol could be taken as "protocol transparent" for outer interfaces meaning that when interfacing the presented system to an outer system users don't have to consider what protocol the outer system transceiving data stream is under for example the TCP/IP protocol or anything else in the case that its I/O interface is a parallel port. Simulation and final experiment prove that the protocol presented is a working solution at a certain bit rate scale. 2012 IEEE.

Image coding using wavelet-based compressive sampling (EI CONFERENCE) 会议论文 OAI收割
2012 5th International Symposium on Computational Intelligence and Design, ISCID 2012, October 28, 2012 - October 29, 2012, Hangzhou, China
作者: Li J.; Li J.; Li J.

收藏 | 浏览/下载：45/0 | 提交时间：2013/03/25

In this paper we proposed a novel coding scheme is proposed using wavelet-based CS framework for nature image. First two-dimension discrete wavelet transform (DWT) is applied to a nature image for sparse representation. After multi-scale DWT the low-frequency sub-band and high-frequency sub-bands are re-sampled separately. According to the statistical dependences among DWT coefficients we allocate different measurements to low- and high-frequency component. Then the measurements samples can be quantized. The quantize samples are entropy coded and forward correct coding (FEC). Finally the compressed streams are transmitted. At the decoder one can simply reconstruct the image via l1 minimization. Experimental results show that the proposed wavelet-based CS scheme achieves better compression performance against the relevant existing solutions.

Performance test of steel tube enclosed thermistors in air temperature measurements (EI CONFERENCE) 会议论文 OAI收割
3rd International Conference on Measuring Technology and Mechatronics Automation, ICMTMA 2011, January 6, 2011 - January 7, 2011, Shanghai, China
作者: Yang H.; Yan F.

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The performances of two steel tube enclosed precision thermistors are tested in a well controlled air environment to determine if the thermistors have enough accuracy for 0.01C levels of air temperature gradient measurement. Three Fluke's 5641 and three 5610 thermistors were tested for 24 hours in Fluke's 7008 calibration bath in the first step. In the second step the performances of these two thermistors in steady state and transient state air temperature environments were tested for 8 hours separately. The results illustrate that two of the 5641s were airproofed in a temperature well controlled tube when steel tube enclosed precision thermistors are used in air temperature measurement there are unstable departures from each other with a maximum 8.8 mC in constant air medium and 27 mC in temperature changing air medium. The transient-time errors are too large to show the true amounts of temperature changes for air temperature measurement. 2011 IEEE.

Distribution of gyroscope accuracy parameters for E-O stabilization platform (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Electric Information and Control Engineering, ICEICE 2011, April 15, 2011 - April 17, 2011, Wuhan, China
作者: Zhang X.; Zhang X.; Zhang X.; Jiang H.

收藏 | 浏览/下载：28/0 | 提交时间：2013/03/25

E-O stabilization platform performance is partly decided by gyroscope precision so it is important to choose a gyroscope with proper accuracy for an E-O stabilization platform. Based on the method of using a gyroscope in practice gyroscope error model is established. With the gyroscope error model gyroscope accuracy parameters that is bias repeatability bias stability scale factor scale factor nonlinearity output noise and bandwidth are separately analyzed. According to the concretely required performance indices for an E-O platform means of distribution of gyroscope accuracy parameters is proposed. A MEMS gyroscope is tested to get the parameters. Bias stability of the gyroscope is 0.08 /s while the bandwidth is 60 Hz. Output noise both at zero input and at nonzero input is analyzed by means of PSD to get the result that nonzero output noise is higher than zero output noise. Frequency response result of the gyroscope is dealt by means of correlation analysis. With all the tested result and the method of distribution of gyroscope accuracy parameters it is clear that how the gyroscope errors works in an E-O servo system. The principle of distribution of gyroscope accuracy parameters is helpful for choosing appropriate gyroscope for an E-O platform. 2011 IEEE.

Station mode for attitude determination of small-multi-target with high speed (EI CONFERENCE) 会议论文 OAI收割
2010 International Conference on E-Product E-Service and E-Entertainment, ICEEE2010, November 7, 2010 - November 9, 2010, Henan, China
作者: Wang J.; Zhao L.; Li M.

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A key problem of attitude measurement of small-multi-target with high speed is how to decide the optimum of the CMOS stations. A multi-CMOS station mode is designed in this paper multiple CMOS videos were placed on two parallel sides in measurement system every two CMOS form an intersection viewing field multiple viewing field join to cover shooting range which can augment Effective Viewing Field(EVF) increase capture ratio of objects with high speed and measurement precision of small objects. When an object passes through the joint area it will be imaged separately on each CMOS focal plane. Multiple CMOS videos were triggered synchronously a sequence of image information was extracted the target attitude was confirmed by digital image processing technology. The merit of station mode is low cost large measurement scope extending freely and so on. 2010 IEEE.

The research for missile bullets' multiple targets of opto-electronic theodolites (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
Wei Z.; Liu Y.-H.

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The system of opto-electronic theodolites for measuring missile bullet provides parameter of missile bullet trajectory and affords primacy scientific data for completing campaign assign and obtaining ideal result of destroy. This article researches extraction arithmetic for missile bullet' multiple targets. Above all enactment threshold of area acquire middle axes of target by adopting Hough transforming and approximating and calculate obliquity angles of targets. In course of matching accomplish missile bullet's multiple targets data association of serial images by making use of improving eigenfunction and achieve extraction of missile bullet's multiple targets after obtaining center position of targets adopting OSTU method change numeral image into binary image according to area of target forecast searching region of target matching by using Kalman filter area of targets and abstract separately center position of targets and area of targets judge conglutination and obstruct then separate targets in term of wave crest and trough's variety of grey histogram of conglutination region grey average of target and obliquity angles of targets. The experimental result shows that right ratio of the extraction targets reach to 90%. The article use correct mathematical model and reasonable arithmetic and obtain effectively parameter of missile bullet' multiple targets. 2010 IEEE. at the same time obtain grey average of target mark target region

Optimizing control mode of optical payloads based on multi-population genetic algorithm (EI CONFERENCE) 会议论文 OAI收割
2009 IEEE International Conference on Mechatronics and Automation, ICMA 2009, August 9, 2009 - August 12, 2009, Changchun, China
Xu W.; Jin G.

收藏 | 浏览/下载：24/0 | 提交时间：2013/03/25

Optimizing the control mode of optical payload could improve the payload's work efficiency. When the mathematic model of payload's control mode was established optimization problems could be boiled down to seek the maximal value of the function with many variables. This paper put forward a calculational method to base the mathematic model the calculational method was multi-population genetic algorithm (MPGA). After the 0-1 variables and real multidimensional ones had been coded separately the algorithm established the populations independently made the multidimensional variables as the centrosome and combined 0-1 ones to work out the maximal value of the function which was established to describe the control mode of the optical payload. Moreover the emulational experiment had been done with the material arithmetic operators. The result indicates that the method using MPGA can hurdle the disadvantage of traditional ones which calculate slowly and get into local best value trap easily . It has the characters that not only fits large scale area scout but also gets the best value in full scale rapidly so this algorithm can better satisfy the technology demand for the intelligent control of optical payload. 2009 IEEE.

Temperature characteristics of several familiar diode lasers with broad area (EI CONFERENCE) 会议论文 OAI收割
Optoelectronic Materials and Devices III, October 27, 2008 - October 30, 2008, Hangzhou, China
作者: Wang L.; Qin L.; Wang L.; Wang L.

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Temperature characteristics of several familiar high power diode lasers with broad area whose wavelength was separately 808 nm 810 nm 940 nm and 980 nm were analyzed. In order to see the effect the change of the quantum well structure on the characteristic temperatures different structures were attempted. For the 808 nm structure we tried different barrier thicknesses. For the 810 nm structure different cavity lengths were attempted. And we studied the 940 nm and 980 nm also. In this paper the widths of these devices were all 100 m. Characteristic temperatures of these devices were calculated. The appropriate structure was available for different application. 2008 SPIE.

Optical fiber transmission of Q-switdied Nd:YAG pulses of 10MW peak power: Mechanism of damage to the fiber (EI CONFERENCE) 会议论文 OAI收割
2nd International Symposium on Advanced Optical Manufacturing and Testing Technologies - Advanced Optical Manufacturing and Testing Technologies, November 2, 2005 - November 5, 2005, Xian, China
作者: Wang L.; Zhang Y.; Chen W.; Tang Y.; Wang L.

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This paper presents theoretical analysis and experiment results of four different fibers transmitting 10MW peak power Nd: YAG laser pulse. The main factors limiting to optical fiber transmission of high power laser pulse is pointed including air breakdown at focus area and surface damage of optical fiber. The theory of air breakdown and the fiber coupling conditions is described briefly. The results of study to the transmission properties and damage conditions are presented on the basis of four different types of optical fibers. The results of the experiments are further analyzed in the aspects of transmitting efficiency air breakdown and surface damage. The local and foreign optical fibers with plastic-cladding and silica-cladding and step- index and graded- index fibers are tested separately in the experiments. The experiments showed that the imported fibers are able to transmit up to 10MW peak power laser pulse with no any visible damage while energy density at the fiber output end surface is 3.54GW/cm2. For local fibers damage on the input surface of both plastic-cladding and silica-cladding step-index fibers was found obviously. The column damage to the graded index fiber was also found and investigated in the research. Damage mechanisms of fiber at high peak power laser pulses are summarized. High quality finishing of fiber end surface will improve damage threshold tremendously. The conclusion of the study is that transmitting Q-switched Nd:YAG pulses of 10MW peak power is feasible for the domestically made fibers if their end surfaces are properly processed.