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Generalized cryptanalysis of RSA with small public exponent

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Science China(information Sciences) 2016年第3期59卷 97-106页

作者： Mengce ZHENG Honggang HU Zilong WANG key laboratory of electromagnetic space information Chinese Academy of Sciences (CAS) School of Information Science and Technology University of Science and Technology of China

In this paper, we demonstrate that there exist weak keys in the RSA public-key cryptosystem with the public exponent e = NαN0.5. In 1999, Boneh and Durfee showed that when α≈ 1 and the private exponent d = Nβ< N0.... 详细信息

关键词： cryptanalysis RSA LLL algorithm Coppersmith’s techniques unravelled linearization

Complex SAR Image Compression Using Entropy-Constrained Dictionary Learning and Universal Trellis Coded Quantization

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Chinese Journal of Electronics 2016年第4期25卷 686-691页

作者： ZHAN Xin ZHANG Rong Department of Electronic Engineering and information Science University of Science and Technology of China key laboratory of electromagnetic space information Chinese Academy of Sciences

In this paper,an Entropy-constrained dictionary learning algorithm(ECDLA) is introduced for efficient compression of Synthetic aperture radar(SAR) complex *** RI encodes the Real and imaginary parts of the images using ECDLA and sparse representation,and ECDLA AP encodes the Amplitude and phase parts *** compared with the compression method based on the traditional Dictionary learning algorithm(DLA),ECDLA RI improves the Signal-to-noise ratio(SNR) up to 0.66 dB and reduces the Mean phase error(MPE) up to 0.0735 than DLA *** the same MPE,ECDLA AP outperforms DLA AP by up to 0.87 dB in ***,the proposed method is also suitable for real-time applications.

关键词： Synthetic aperture radar image compression Dictionary learning Sparse representation

Target decomposition and recognition from wide-angle SAR imaging based on a Gaussian amplitude-phase model

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Science China(information Sciences) 2017年第6期60卷 212-224页

作者： Yongchen LI Ya-Qiu JIN key laboratory for information Science of electromagnetic Waves Fudan University

Wide-angle synthetic aperture radar(W-SAR) imaging accounts for multi-azimuthal scattering and is feasible for retrieving more comprehensive features of complex targets. Because a typical target is seen as composed of its components(typically, some simple geometric objects), a Gaussian amplitude-phase(GAP)model has been developed for the analysis of multi-azimuthal scattering from these objects. Based on the timefrequency analysis of wide-angle scattering, the parameters of the GAP model were estimated, including the Gaussian variance, the surface curvature, and the number of objects in all imaged pixels. Numerical simulations and real measurements demonstrate the capability of the GAP model for decomposing and recognizing complex electric-large targets.

关键词： wide-angle SAR Gaussian amplitude-phase time-frequency target decomposition target recognition

Imaging and structural feature decomposition of a complex target using multi-aspect polarimetric scattering

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Science China(information Sciences) 2016年第8期59卷 220-233页

作者： Yongchen LI Ya-Qiu JIN key laboratory for information Science of electromagnetic Waves Fudan University

Based on the Huynen parametric decomposition of target scattering matrix, the polarimetric ellipse parameters are transformed and applied to decomposition of scattering mechanisms of a complex target in VHR POL-SAR images(very high resolution, polarimetric synthetic aperture radar). Making use of multi-aspect(or circle-aspect) and wideband VHR POL-SAR images, scattering mechanisms of a volumetric target and its structural components are recognized over image pixels. Utilizing the layover features, the target height profile is also estimated from two-dimensional image. As example, polarimetric scattering data of some vehicles on ground, including multi-aspect simulated data and experimental measurements, are applied to validations of scattering mechanism decompositions and target structural feature recognition.

关键词： scattering mechanism polarimetric decomposition multi-aspect imaging target recognition

The Weight Distribution of a Class of p-Ary Cyclic Codes with Few Weights

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Chinese Journal of Electronics 2020年第4期29卷 717-723页

作者： LIU Li XIE Xianhong School of Mathematics Hefei University of Technology key laboratory of electromagnetic space information CAS University of Science and Technology of China

In this paper, we investigate a class of p-ary cyclic codes whose duals have two zeros for some special cases and calculate their weight distributions *** results show that the codes have at most five nonzero ***, the... 详细信息

关键词： Cyclic codes Weight distributions Fourier expansion Gauss sums Griesmer bound

AI based on frequency slicing deep neural network for underwater visible light communication

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Science China(information Sciences) 2020年第6期63卷 47-54页

作者： Nan CHI Fangchen HU Guoqiang LI Chaofan WANG Wenqing NIU key laboratory for information Science of electromagnetic Waves (MoE) Fudan University

In this paper, we propose a low-complexity frequency slicing deep neural network(FSDNN) for wide-band signal post-equalization in a 1.2 m underwater visible light communication system. FSDNN and deep neural network(DNN) outperform the least mean square equalizer. Then, by splitting the received signal into two parallel signals using a digital low-pass filter and a high-pass filter, we demonstrate that the FSDNN significantly reduces the complexity of the traditional DNN post-equalizer. Moreover, the complexity of the FSDNN decreases considerably to 11.15% compared with the conventional DNN for a 2.7 Gbit/s wide-band transmitted signal with a similar bit error ratio performance.

关键词： deep neural network frequency slicing underwater visible light communication visible light communication

Support vector machine based machine learning method for GS 8QAM constellation classification in seamless integrated fiber and visible light communication system

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Science China(information Sciences) 2020年第10期63卷 182-193页

作者： Wenqing NIU Yinaer HA Nan CHI key laboratory for information Science of electromagnetic Waves (MoE) Fudan University

Visible light communication(VLC) network over optical fiber has become a potential candidate in ultra-high speed indoor wireless communication. To mitigate signal distortion accumulated in optical fiber and VLC channel, we present to utilize support vector machine(SVM) for constellation classification in two kinds of geometrically-shaped 8 QAM(quadrature amplitude modulation) seamless integrated fiber and VLC system. We introduce 4 sub-bands to simulate multi-user. Experimental results show that system performance can be significantly improved, and transmission at-2.5 dB m input optical power under 7%forward error correction(FEC) threshold can be realized employing Circular(7, 1) geometrically-shaped8 QAM and SVM. At overall capacity of 960 Mbps, Q-factor increases by up to 11.5 dB.

关键词： visible light communication VLC support vector machine SVM geometrically shaping GS VLC network constellation classification

Incorporating Spatial Distribution Feature with Local Patterns for Content-Based Image Retrieval

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Chinese Journal of Electronics 2016年第5期25卷 873-879页

作者： WAN Shouhong JIN Peiquan XIA Yu YUE Lihua Institute of Compute Science and Technology University of Science and Technology of China Key Laboratory of Electromagnetic Space Information Chinese Academy of Sciences

Local patterns record the gray-level differences between a referenced pixel in an image and its surrounding pixels, which have been commonly used to describe the image features. However, traditional local patterns ignore the spatial distribution feature of texture information in images. We group the gray-level variations along three directions, i.e., horizontal, vertical, and diagonal directions. Each group is then merged into a Local spatial distribution pattern(LSDP) to represent the spatial distribution image feature. We also construct the LSDP patterns for gradient and filtered images, and finally form the Complete local spatial distribution pattern(CLSDP)descriptor to completely describe the texture image feature. Experiments on textural and natural image sets were conducted to compare our CLSDP-based image retrieval algorithm with four previous competitors. The results show that our method is superior to existing algorithms considering both average precision and recall.

关键词： Feature extraction or construction Image retrieval Feature representation

Square Geometrical Shaping 128QAM Based Time Domain Hybrid Modulation in Visible Light Communication System

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China Communications 2020年第1期17卷 163-173页

作者： Peng Zou Yiheng Zhao Fangchen Hu Nan Chi key laboratory for information Science of electromagnetic Waves Fudan University

We proposed two kinds of visible light communication(VLC)systems which respectively based on 64QAM/square geometrical shaping(SGS)128QAM time domain hybrid modulation scheme(SGSHY)and 64QAM/128QAM time domain hybrid modulation scheme(REGHY).These two systems can operate around specific forward error correction(FEC)threshold and maximize the achievable information rate(AIR)of the *** principles of SGSHY and REGHY are proposed in detail,which has very low computation complexity compared with probabilistic *** SGSHY outperforms REGHY at high peak to peak voltage(Vpp).Experimental results show that at high Vpp like 1.4V,which means the system is suffering from high nonlinear distortion,the AIR of SGSHY outperforms that of REGHY by 0.12Gb/s at the 2×10-2 FEC *** AIR of the REGHY is at most 0.36Gb/s higher than that of 64QAM at 0.8V Vpp and 7%FEC threshold,while the(achievable information rate)AIR of SGSHY is at most 0.40Gb/s higher than that of 64QAM at 1.4V Vpp and 20%FEC threshold.

关键词： SGS128QAM MPN TDHM nonlinear distortion achievable information rate

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