中国科学院机构知识库网格系统: 检索

IM2Vec: Representation learning-based preference maximization in geo-social networks 期刊论文 OAI收割
INFORMATION SCIENCES, 2022, 卷号: 604, 页码: 170-196
作者: Jin, Ziwei; Shang, Jiaxing; Ni, Wancheng; Zhao, Liang; Liu, Dajiang

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收藏 | 浏览/下载：50/0 | 提交时间：2022/07/25

Influence maximization Representation learning Location-based social networks Diffusion model Reverse influence sampling

N-enrichment induced biodiversity loss can be explained by reductions in competitive intransitivity: Evidence from a decade-long grassland experiment 期刊论文 OAI收割
ENVIRONMENTAL AND EXPERIMENTAL BOTANY, 2021, 卷号: 184
作者: Liu, Lian; Cheng, Junhui; Li, Yawen; Lan, Zhichun; Bai, Yongfei

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收藏 | 浏览/下载：23/0 | 提交时间：2023/02/24

Competitive intransitivity Sampling scale N fertilization Markov chain model Trait-based functional groups

A Literature Review of UAV 3D Path Planning 会议论文 OAI收割
Shenyang, China, June 29 - July 4, 2014
作者: Yang L(杨亮); Qi JT(齐俊桐); Xia Y(夏泳)

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收藏 | 浏览/下载：14/0 | 提交时间：2014/12/29

Uav 3d Path Planning Sampling Based Algorithms Node Based Algorithms Multi-fusion Based Algorithms Mathematic Model Based Algorithms

Comparison and simulation of subpixel imaging modes for linear CCD (EI CONFERENCE) 会议论文 OAI收割
2012 3rd International Conference on Information Technology for Manufacturing Systems, ITMS 2012, September 8, 2012 - September 9, 2012, Qingdao, China
作者: Li Y.; He B.; Li Y.; Li Y.; Li Y.

收藏 | 浏览/下载：37/0 | 提交时间：2013/03/25

Subpixel technique of linear CCD is effective to enhance the spatial resolution without increasing the focal length of optics and reducing the pixel size. To compare image quality of two main subpixel imaging modes quincunx sampling and four-point sampling a method to quantitatively evaluate image quality of subpixel based on MTF was proposed. The MTF of quincunx and four-point sampling modes were derived. Analytical results shows that theoretical limiting resolution of quincunx sampling and four-point sampling is improved to 1.4 and 1.86 times respectively and MTF values at Nyquist frequency of two modes are increased by 0.1106 and 0.1679 respectively. MTFA in (0 0.5) of two subpixel imaging modes were calculated and results illustrates that four-point sampling offers much more improvement with image quality than quincunx sampling at the cost of double amount of data. A model for simulating subpixel imaging using Matlab was established and simulation results of spoke target verify the theoretical analysis. (2012) Trans Tech Publications Switzerland.

Effect of the sampling design of ground control points on the geometric correction of remotely sensed imagery 期刊论文 OAI收割
INTERNATIONAL JOURNAL OF APPLIED EARTH OBSERVATION AND GEOINFORMATION, 2012, 卷号: 18, 页码: 91-100
Wang, JH(王江浩); Ge, Y; Heuvelink, GBM; Zhou, CH; Brus, D

收藏 | 浏览/下载：21/0 | 提交时间：2012/08/30

Geometric correction Spatial coverage sampling Universal kriging Variogram Model-based sampling

Effect of the sampling design of ground control points on the geometric correction of remotely sensed imagery SCI/SSCI论文 OAI收割
2012
作者: Ge Y.

收藏 | 浏览/下载：23/0 | 提交时间：2014/12/24

Geometric correction Spatial coverage sampling Universal kriging Variogram Model-based sampling resolution satellite imagery accuracy registration algorithm model

The application of template matching arithmetic on Strap-down North Seeking System (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Mechatronic Science, Electric Engineering and Computer, MEC 2011, August 19, 2011 - August 22, 2011, Jilin, China
Li D.-N.; Zhu W.; Chen T.

收藏 | 浏览/下载：18/0 | 提交时间：2013/03/25

In order to solve the problem of self-determination directional of theodolite equipment based on dynamically tuned gyroscope is proposed. The principle of the Multi-position Strap-down North Seeking System is introduced. Mathematical model of the system is discussed. The factors that influence the precision are analyzed. In order to fit the curve of sampling data back-propagation neural network arithmetic is used in data processing. As templates curve model is saved at database of the VC software. The template matching arithmetic advanced the measure precision of this system. The measure time of the system is shortened within 1 minute so it can save time for theodolite. 2011 IEEE.

Analyse the angular velocity estimation errors of -- filter based on high sampling rate (EI CONFERENCE) 会议论文 OAI收割
2011 2nd International Conference on Mechanic Automation and Control Engineering, MACE 2011, July 15, 2011 - July 17, 2011, Inner Mongolia, China
作者: Zhang Y.

收藏 | 浏览/下载：31/0 | 提交时间：2013/03/25

In order to get angular velocity of stabilization servo mechanism from angular position sensors -- filter based on high sampling rate was established model and error characteristics were analyzed. With the hypothesis of constant acceleration -- filter and its angular velocity transfer function were deduced. Combing with optimum parameters the effects of and sample rate on the error characteristics were evaluated. According to the requirements of stabilization servo mechanism the frequency characteristics of angular velocity transfer function are analyzed and the filter parameters are designed. The experimental which filter tracked and smoothed sinusoidal signal the results show that when the cutoff frequency of angular velocity loop is 44.9rad/s sampling period and parameters are 0.08ms and 0.01279 respectively the phase leading of angular position is 70. -- filter tracked sinusoidal signals with maximum angular velocity(30/s) and maximum angular acceleration(30/s2) the error of angular velocity estimation was 0.053/s. In the engineering of electro-optical stabilization servo mechanism -- filter can reduce noise effectively and reached the requirement of platform angular velocity estimation. Also it is one of the effective methods to get angular velocity from angular position sensors. 2011 IEEE.

Modulation transfer function measurement of sampled imaging systems in field test (EI CONFERENCE) 会议论文 OAI收割
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, April 26, 2010 - April 29, 2010, Dalian, China
作者: Yang L.; Zhang J.; Zhang J.; Zhang J.; Wang J.

收藏 | 浏览/下载：27/0 | 提交时间：2013/03/25

A digital mirror device (DMD) based light projector was developed as the target generator in modulation transfer function (MTF) measurement. In order to overcome the sampling-scene phase effect in MTF measurement of sampled imaging systems a method using random targets is introduced to yield a phase-averaged MTF. The main potential problem of implementing this method is the fact that the stationary assumption of the random targets may be vitiated in practical measurement especially in field test due to the ill condition. We provide an efficient model-independent way of analyzing and isolating the spectral contents arising from these additional contributions to MTF measurement. Algorithms with adaptive parameter selection were also developed for spectral estimation of the test image in order to overcome the challenge brought by the size limit of the test matrices for one certain field of view derived from the isoplantic region. The MTF measurement of a CCD video imager is used to demonstrate the measurement technique and illustrate the benefits over other methods. In order to validate the results comparisons have been made between MTF measurements of imager implemented using this method and bar target direct measurements. 2010 Copyright SPIE - The International Society for Optical Engineering.

Adaptive sliding mode control for airborne Opto-Electronic platform servo system (EI CONFERENCE) 会议论文 OAI收割
7th International Conference on Machine Learning and Cybernetics, ICMLC, July 12, 2008 - July 15, 2008, Kunming, China
Wang C.-X.; Liu J.-H.; Shen H.-H.; Dai M.

收藏 | 浏览/下载：21/0 | 提交时间：2013/03/25

The novel presents an adaptive reaching law sliding mode controller to slove a class of uncertain systems.The Airborne Opto-Electronic Platform sliding model is employed to represent a class of complex uncertain system. The control is based on reaching law control. Discrete time implementation of the sliding mode control strategy is considered in the paper since it is more appropriate for practical applications. It is shown that the robustness of the sliding mode control method is constrained by sampling time. Design of the adaptive reaching law based on a discrete expotential reaching law concept is given which to design a new sliding mode controller based on Lyapunov stability theory. The global asymptotic stability is guaranteed. An example with simulation results is given to illustrate the effectiveness of the proposed method. 2008 IEEE.