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IEEE International geoscience and Remote Sensing Symposium

作者： Jiayin Liu Xiaolan Qiu Yuxin Hu Wen Hong Institute of Electronics Chinese Academy of Sciences Beijing China University of Chinese Academy of Sciences Beijing China Key Laboratory of Technology on Geo-spatial Information Processing and Application System Chinese Academy of Sciences Beijing China National Key Laboratory of Microwave Imaging Technology Beijing China

HJ-1C satellite was launched in November 2012 as the first civil spaceborne SAR system of S band in China. Since the image geolocation is essential for the quantificational study of the system specifications of HJ-1C, the paper focuses on the geolocation of HJ-1C SAR image, including the systematic position accuracy of HJ-1C satellite image, and the higher position accuracy with GCPs (ground control point). In addition, a novel equivalent-range-doppler method is presented in this paper to geolocate HJ-1C satellite image using only one GCP.

关键词： Mathematical model Satellites Equations Synthetic aperture radar Accuracy geology Spaceborne radar

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A Cloaking-Based Approach to Protect Location Privacy in Location-Based Services

A Cloaking-Based Approach to Protect Location Privacy in Loc...

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第三十三届中国控制会议

作者： Zheng Jiangyu Tan Xiaobin Cliff Zou Niu Yukun Zhu Jin CAS Key Laboratory of Technology in Geo-spatial Information Processing and Application System University of Science and Technology of China Department of Automation University of Science and Technology of China Department of Electrical Engineering and Computer Science University of Central FloridaOrlandoFL 32816-2362

ISBN: (纸本)9781479947249

With the widespread use of mobile devices, the location-based service(LBS) applications become increasingly popular, which introduces the new security challenge to protect user's location privacy. On one hand, a user expects to report his own location as far as possible away from his real location to protect his location privacy. On the other hand, in order to obtain high quality of service(QoS), users are required to report their locations as accurate as possible. To achieve the dedicated tradeoff between privacy requirement and QoS requirement, we propose a novel approach based on cloaking technique. We also discuss the disadvantage of the traditional general system model and propose an improved model. The basic idea of our approach is to select a sub-area from the generated cloaking area as user's reported location. The sub-area may not contain a user's real location,which prevents an adversary from performing attack with side information. Specifically, by defining an objective function with a novel location privacy metric and a QoS metric, we are able to convert the privacy issue to an optimization problem. Then, location privacy metric and QoS metric are given. To reduce the complexity of the optimization, a heuristic algorithm is *** privacy-preserving analysis and comparison with related work [8], we demonstrate the effectiveness and efficiency of our approach.

关键词： Location-based Services,Location Privacy,k-anonymity,Cloaking Area

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Outage Analysis of Dual-Hop Transmission with Buffer Aided Amplify-and-Forward Relay

Outage Analysis of Dual-Hop Transmission with Buffer Aided A...

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IEEE Vehicular technology Conference

作者： Guan-Xing Li Chen Dong Dong Liu Guangtao Li Yonghui Zhang China Mobile Group Liaoning Ltd. School of ECS University of Southampton CAS Key Laboratory of Technology in Geo-spatial Information Processing and Application System University of Science and Technology of China RF Micro Devices Co. Ltd.

ISBN: (纸本)9781479944484

A new packet-selection based transmission scheme is proposed on a dual-hop link with buffer aided amplify-and-forward relay, where the relay with a buffer can record the channel information of source-relay hop and store the received packets. In order to satisfy the constraint of equivalent end-to-end SNR, the relay may pick up a packet in the buffer to transmit, with consideration of the channel statuses of both the source-relay hop and the relay-destination hop. Therefore, by adjusting the packet transmission order in the relay, the outage probability can be decreased in the proposed transmission scheme. Both theoretical analyses and simulation results show that the proposed scheme outperforms traditional ones by a significant margin of 2-4 dB gain in terms of outage probability.

关键词： Relays Signal to noise ratio Fading Tin Delays Wireless communication Buffer storage

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Threshold determination for dynamic programming based track-before-detect in passive bistatic radar

Threshold determination for dynamic programming based track-...

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International Conference on Signal processing Proceedings (ICSP)

作者： Xin Guan Li-hua Zhong Dong-hui Hu Chi-biao Ding Key Laboratory of Technology in Geospatial Information Processing and Application System Institute of Electronics Chinese Academy of Sciences Beijing CN

Track-before-detect (TBD) is effective on weak target detection in passive bistatic radar (PBR). The probability of false alarm (PFA) and the probability of detection (PD) in TBD based on dynamic programming algorithm (DPA) are determined by threshold. The extreme value theory and generalized Pareto distribution are usually used to obtain the relationship between PD, PFA and threshold. However, DPA must be performed several times to estimate parameters resulting in much processing time. An iterative method based on Gaussian distribution is another solution but is not suitable for the Chi-square distribution in PBR. Therefore fast threshold determination methods without Gaussian assumption are proposed in this paper. First, a data simulation method is presented. Then an approximation of PD is introduced to further reduce the complexity. Moreover, empirical formulas based on the hypothesis of Chi-square distribution are developed for real-time processing. Simulations verify that the methods are more suitable for real-time processing.

关键词： Approximation methods Data models Monte Carlo methods Noise Complexity theory Target tracking Real-time systems

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Fuzzy-logic based adaptive weighting filter for strap-down inertial navigation systems

Fuzzy-logic based adaptive weighting filter for strap-down i...

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World Congress on Intelligent Control and Automation (WCICA)

作者： Wenjun Lv Yu Kang Zhijun Li Yun-Bo Zhao Department of Automation & CAS Key Laboratory of Technology in Geo-spatial Information Processing and Application System University of Science and Technology of China Hefei Anhui Province China College of Automation Science and Engineering South China University of Technology Guangzhou Guangdong Province China College of Information Engineering Zhejiang University of Technology Hangzhou Zhejiang Province China

Strap-down inertial navigation systems are widely applicable in both military and civil industries. The outputs of gyroscope and accelerometer are polluted by noises. Different form the conventional technologies, the weighting filter presented in this work is superior to both the complementary filter and Kalman filter. Furthermore, to eliminate the negative effects brought by the variation of noise statistical characteristics, a fuzzy-logic based regulator is introduced to adjust the weight coefficient adaptively. Finally, experiments are conducted to validate the efficiency of the filter.

关键词： Noise Gyroscopes Accelerometers Kalman filters Accuracy Mathematical model Educational institutions

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Nonparametric statistics inspired similarity measure for accuracy in collaborative filtering

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Journal of Computational information systems 2013年第20期9卷 8397-8406页

作者： Liu, Shichen Xiong, Yan Liu, Qingwen Qi, Xiang Department of Computer Science and Technology University of Science and Technology of China Hefei 230027 China Key Laboratory of Technology in Geo-Spatial Information Processing and Application System Institute of Electronics Chinese Academy of Sciences Beijing 100190 China

Similarity computation is especially significant in collaborative filtering algorithms. In the existed literatures or large recommender systems, researchers generally use cosine similarity or Pearson correlation coefficient to compute the similarities. However, on one hand, both two measures are more applicable in linear space while the ratings cannot linearly reflect users' interest intensity. On the other hand, different systems have different rating restricts, so it's unreasonable to treat varied systems with the same computation method. In this work, inspired by nonparametric statistics, a sound memory-based method with a novel similarity measure is proposed to eliminate the affection of rating distributions and system diversities on similarity computation. Experiments based on Jester are set to evaluate the performance of the approach. And the highly competitive results show that our approach is able to significantly improve the recommendation quality. © 2013 Binary information Press.

关键词： Collaborative filtering

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A cloud detection method based on a time series of MODIS surface reflectance images

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International Journal of Digital Earth 2013年第S01期6卷 157-171页

作者： Hairong Tang Kai Yu Olivier Hagolle Kang Jiang Xiurui Geng Yongchao Zhao Key Laboratory of Technology in Geo-spatial information Processing and Application System Institute of ElectronicsChinese Academy of ScienceBeijingChina CESBIO Universite´de ToulouseUnite´mixte CNES CNRS IRD UPSToulouse Cedex 4France

The Moderate Resolution Imaging Spectroradiometer(MODIS)-Terra surface reflectance product(MOD09A1),with bands 1 to 7,is a gridded,eight-day composite product derived from the MODIS-Terra top of atmosphere reflectance *** performs cloud detection and corrects for the effects of atmospheric gases and *** cloud mask(CM)algorithms for MODIS are based on empirical thresholds on spectral reflectance and brightness *** the spatial resolution of the thermal band is 1000 m,while that of MOD09A1 is 500 m,many undetected and false clouds are observed in *** errors always result in temporal and spatial inconsistencies in higher-level *** this paper,a cloud detection algorithm(TSCD)based on a MOD09A1 time series is *** series cloud detection(TSCD)algorithm is based on the relative stability of ground reflectance and the sudden variations in reflectance that result from cloud *** algorithm first searches the clear-sky reference data,and then discriminates clouded and unclouded pixels by detecting a sudden change of reflectance in the blue wavelength and spectral correlation coefficient at the pixel *** with cloud cover assessments obtained from MODIS’original CM,TSCD provides similar or better discrimination in most situations when the land surface changes slowly.

关键词： MODIS surface reflectance time series cloud detection BRDF

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Sensitivity analysis of along-track interferometric synthetic aperture radar (ATI-SAR) in the presence of squint

Sensitivity analysis of along-track interferometric syntheti...

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IET International Radar Conference 2013

作者： Hui, Zhang Jun, Hong University of Chinese Academy of Sciences Beijing China Chinese Academy of Sciences Beijing Institute of Electronics China Key Laboratory of Technology in Geo-Spatial Information Processing and Application System Technology Beijing China Science and Technology on Microwave Imaging Laboratory Beijing China

ISBN: (纸本)9781849196031

Along-Track Interferometric Synthetic Aperture Radar (ATISAR) has the potential of measuring the radial velocity of the slowly moving target. The accuracy of the radial velocity is mainly determined by the accuracy of the interferometric parameters. Sensitivity equations are good ways of analysing the impacts of system parameters for interferometric SAR. Former sensitivity analysis for ATI-SAR has been mainly focused on the case of no squint angle. In this paper, we explain the necessity of analysing the sensitivity equations in the presence of squint angle. Then the expression of the radial velocity in the presence of squint is derived and the sensitivity equations are obtained. Finally, the sensitivity of some interferometric parameters and the impact of squint angles are analysed and simulated for a particular accuracy requirement.

关键词： Sensitivity analysis

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Rapid face image retrieval with pose-based local features and multi-reference re-ranking

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Journal of Computational information systems 2013年第1期9卷 223-230页

作者： Zhen, Haiyang Zeng, Lingzi Zhang, Rong Yin, Dong Department of Electronic Eng. and Information Science University of Science and Technology of China Hefei 230027 China Key Laboratory of Geospatial Information Processing and Application System Technology Chinese Academy of Sciences Beijing 100190 China

The performance of state-of-art image retrieval systems using Bag-of-Words representation and textual retrieval methods degrades quickly when applied to face images because their local features can not suffer variations of illumination, pose and expression of human face. Moreover, most discriminative facial features are typically high-dimensional and global, and not suitable for rapid retrieval. Motivated by the observation that local features and global features are complementary, we propose a rapid face image retrieval approach using both local and global features in this paper. To ensure the high speed of retrieval, an inverted index is built by quantizing pose-based local features specially designed for face images on component level. Candidate images with low precision and high recall can be obtained using inverted index of visual words in the retrieval stage. Global facial features and multi-reference method are used to obtain a final retrieval list with high precision. Experiments on a 160k face dataset downloaded from the internet show our approach can achieve a high precision and a high speed. © 2013 Binary information Press.

关键词： Indexing (of information)

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Self-adaptive optical image registration based on optimized analysis of feature points

Self-adaptive optical image registration based on optimized ...

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第二届高分辨率对地观测学术年会

作者： Shi Yue Zhang Daobing Institute of Electronic Chinese Academy of SciencesBeijing 100190China Key Laboratory of Spatial Information Processing and Application System Technology Chinese Academy o

Image registration is an important preprocessing step for image processing such as change detection,image mosaicking in remote sensing,however a crucial problem involved feature-based image registration is how to reliably establish correspondent features between sensed image and reference *** paper presents an automatic self-adaptive image registration method based on analytic energy of control points to improve the traditional ***,an multi-scale segment method based on digital curvelet transform is used to evaluate the quality difference of image pairs,and then self-adaptive parameters of SIFT feature-matching algorithm based on multi-scale grey relation of image quality is proposed to increase the feature points and correspondences;At last,to make sure the accuracy of geometrical transform parameters,a method of correspondences selection based on the distribution and matching energy of control points is *** results demonstrate that the proposed method works well in increasing control points and the correspondences of low quality remote sensing images.

关键词： Image Registration Scale Invariant Feature Transform (SIFT) Self-adaptive keypoint refinement

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