检索结果-南通市图书馆

Image Hiding with High Robustness Based on Dynamic Region Attention in the Wavelet Domain

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & sciences 2024年第10期141卷 847-869页

作者： Zengxiang Li Yongchong Wu Alanoud Al Mazroa Donghua Jiang jianhua Wu Xishun Zhu department of information Engineering Gongqing CollegeNanchang UniversityJiujiang332020China School of information Engineering Gongqing Institute of Science and TechnologyJiujiang332020China department of information Systems College of Computer and Information SciencesPrincess Nourah bint Abdulrahman UniversityRiyadh11671Saudi Arabia School of Computer science and Engineering Sun Yat-sen UniversityGuangzhou511400China School of information Engineering Nanchang UniversityNanchang330031China School of mathematics and Statistics Hainan Normal UniversityHaikou571158China

Hidden capacity,concealment,security,and robustness are essential indicators of hiding ***,hiding algorithms tend to focus on algorithmic capacity,concealment,and security but often overlook the robustness of the *** practical applications,the container can suffer from damage caused by noise,cropping,and other attacks during transmission,resulting in challenging or even impossible complete recovery of the secret *** image hiding algorithm based on dynamic region attention in the multi-scale wavelet domain is proposed to address this issue and enhance the robustness of hiding *** this proposed algorithm,a secret image of size 256×256 is first decomposed using an eight-level Haar wavelet *** wavelet transform generates one coefficient in the approximation component and twenty-four detail bands,which are then embedded into the carrier image via a hiding *** the recovery process,the container image is divided into four non-overlapping parts,each employed to reconstruct a low-resolution secret *** lowresolution secret images are combined using densemodules to obtain a high-quality secret *** experimental results showed that even under destructive attacks on the container image,the proposed algorithm is successful in recovering a high-quality secret image,indicating that the algorithm exhibits a high degree of robustness against various *** proposed algorithm effectively addresses the robustness issue by incorporating both spatial and channel attention mechanisms in the multi-scale wavelet domain,making it suitable for practical *** conclusion,the image hiding algorithm introduced in this study offers significant improvements in robustness compared to existing *** ability to recover high-quality secret images even in the presence of destructive attacksmakes it an attractive option for various *** research and experimentation can explore the algorith

关键词： Image hiding robustness wavelet transform dynamic region attention

A NEW UEP SCHEME FOR ROBUST VIDEO TRANSMISSION IN LDPC CODED MIMO-OFDM SYSTEM

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Electronics(china) 2007年第3期24卷 396-401页

作者： Ru Congchong Zheng Haifeng yin Liuguo Lu jianhua Chen Changwen department of Electronic Engineering Tsinghua University Beijing 100084 China college of information technology Fuzhou University Fuzhou 350002 China Dept. Electrical ＆ Computer Eng. Florida Institute of Technology Melbourne FL 32040 USA

In order to improve the video transmission performance in Multiple-Input Multiple-Output Orthogonal Frequency Division Multiplexing （MIMO-OFDM） system, a new scheme, which integrates Multiple Description Coding （MDC）, Low Density Parity Check （LDPC） coding and hybrid space time coding, is proposed in this letter. In particular, a hybrid space time coding algorithm is combined with LDPC codes to perform Unequal Error Protection （UEP） of MDC encoded video streams. Comparing with the UEP transmission with only LDPC codes, the proposed scheme achieves more than ldB gain in terms of Signal to Noise Ratio （SNR） when the Peak Signal to Noise Ratio （PSNR） of reconstructed video is above 30dB.

关键词： Multiple-Input Multiple-Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) Multiple Description Coding (MDC) Low Density Parity Check (LDPC) Unequal Error Protection (UEP)

Efficient Helicopter-Satellite Communication Scheme Based on Check-Hybrid LDPC Coding

在线全文

学校读者我要写书评

暂无评论

Tsinghua science and technology 2018年第3期23卷 323-332页

作者： Ping Wang Liuguo yin jianhua Lu department of Electronic Engineering Tsinghua University Beijing 100084 China EDA Laboratory Research Institute of Tsinghua Universityin Shenzhen Shenzhen 518057 China. School of information science andtechnology Tsinghua University Beijing 100084 China EDA Laboratory Research Institute ofTsinghua University in Shenzhen Shenzhen 518057 China department of Electronic Engineering Tsinghua University Beijing 100084 China

When implementing helicopter-satellite communications, periodical interruption of the received signal is a challenging problem because the communication antenna is intermittently blocked by the rotating blades of the helicopter. The helicopter-satellite channel model and the Forward Error Control（FEC） coding countermeasure are presented in this paper. On the basis of this model, Check-Hybrid（CH） Low-Density Parity-Check（LDPC）codes are designed to mitigate the periodical blockage over the helicopter-satellite channels. The CH-LDPC code is derived by replacing part of single parity-check code constraints in a Quasi-Cyclic LDPC（QC-LDPC） code by using more powerful linear block code constraints. In particular, a method of optimizing the CH-LDPC code ensemble by searching the best matching component code among a variety of linear block codes using extrinsic information transfer charts is proposed. Simulation results show that, the CH-LDPC coding scheme designed for the helicopter-satellite channels in this paper achieves more than 25% bandwidth efficiency improvement, compared with the FEC scheme that uses QC-LDPC codes.

关键词： helicopter-satellite communications check-hybrid Low-Density Parity-Check(LDPC) codes Extrinsic information Transfer(EXIT) iterative decoding

Security of quantum key distribution with virtual mutually unbiased bases

在线全文

学校读者我要写书评

暂无评论

science china(Physics,Mechanics & Astronomy) 2024年第7期67卷 13-21页

作者： Hong-Wei Li Chen-Peng Hao Zhi-Jiang Chen Li Gong Yi-Fei Lu Yang Wang Jia-Ji Li Chun-Mei Zhang Rong Wang Zhen-Qiang yin Qing-Yu Cai Henan Key Laboratory of Quantum information and Cryptography SSF IEUZhengzhou 450000China Institute of Quantum information and technology Nanjing University of Posts and TelecommunicationsNanjing 210003China department of Physics University of Hong KongHong Kong 999077China Key Laboratory of Quantum information University of Science and Technology of ChinaHefei 230026China School of information and Communication Engineering Hainan UniversityHaikou 570228China

In a perfect quantum key distribution(QKD)protocol,quantum states should be prepared and measured with mutually unbiased bases(MUBs).However,in a practical QKD system,quantum states are generally prepared and measured with imperfect MUBs using imperfect devices,possibly reducing the secret key rate and transmission *** analyze the security of a QKD system with imperfect MUBs,we propose virtual MUBs to characterize the quantum channel against collective attack,and analyze the corresponding secret key rate under imperfect state preparation and measurement *** generally,we apply the advantage distillation method for analyzing the security of QKD with imperfect MUBs,where the error tolerance and transmission distance can be sharply *** analysis method can be applied to benchmark and standardize a practical QKD system,elucidating the security analysis of different QKD protocols with imperfect devices.

关键词： quantum key distribution mutually unbiased bases advantage distillation

Realization of quantum secure direct communication over 100 km fiber with time-bin and phase quantum states

在线全文

学校读者我要写书评

暂无评论

Light(science & Applications) 2022年第5期11卷 787-795页

作者： Haoran Zhang Zhen Sun Ruoyang Qi Liuguo yin Gui-Lu Long jianhua Lu State Key Laboratory of Low-Dimensional Quantum Physics and department of Physics Tsinghua UniversityBeijingChina Beijing Academy of Quantum information science BeijingChina School of information and technology Tsinghua UniversityBeijingChina Beijing Institute of Spacecraft System Engineering BeijingChina Frontier science Center for Quantum information BeijingChina Beijing National Research Center for information science and technology BeijingChina

Rapid progress has been made in quantum secure direct communication in recent *** practical application,it is important to improve the performances,such as the secure information rate and the communication *** this paper,we report an elaborate physical system design and protocol with much enhanced *** design increased the secrecy capacity greatly by achieving an ultra-low quantum bit error rate oftechnology.

关键词： fiber communication quantum

Solid-state NMR studies on the organic matrix of bone

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2023年第2期16卷 2980-2990页

作者： Hua-Dong Xue Yu yin Tian He Haixin Song jianhua Li Xueqian Kong department of Rehabilitation Sir Run Run Shaw HospitalCollege of MedicineZhejiang UniversityHangzhou 310016China department of Chemistry Zhejiang UniversityHangzhou 310027China

Bone is a hierarchical architecture that consists of both inorganic and organic *** organic components,including collagen and numerous non-collagenous biomolecules,are crucial for maintaining the mechanical strength and physiological functions of *** native structures of organic components and especially the mutual interactions between different components are important questions to be *** different analytical techniques,solid-state nuclear magnetic resonance(SSNMR)spectroscopy is a powerful tool to reveal the chemical and interactional information at an atomic *** advancements of SSNMR technology and experimental protocols have brought great advances in understanding the molecular details in native *** this review,we summarize the progresses on the SSNMR studies of various organic components in the bone *** the first part,we review the studies on collagen from four different aspects:(1)waterassociated molecular dynamics;(2)the intrahelical/interhelical interactions in collagen residues;(3)the interactions between collagen and citrate;and(4)the cross-linking between collagen and inorganic *** the second part,we review the studies on the non-protein biomolecules including sugar species,citrate,lipids,and nucleic *** the end,we propose an outlook of future directions for SSNMR investigations on bones.

关键词： bone matrix solid-state nuclear magnetic resonance(SSNMR) collagen dynamics biomineralization

An efficient flood dynamic visualization approach based on 3D printing and augmented reality

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Digital Earth 2020年第11期13卷 1302-1320页

作者： Guoyong Zhang jianhua Gong Yi Li Jun Sun Bingli Xu Dong Zhang Jieping Zhou Ling Guo Shen Shen Bingxiao yin National Engineering Research Center for Geoinformatics Aerospace Information Research Institute(AIR)Chinese Academy of SciencesBeijingPeople’s Republic of China university of Chinese Academy of sciences BeijingPeople’s Republic of China Zhejiang-CAS Application Center for Geoinformatics ZhejiangPeople’s Republic of China Jiaxing Hetu Remote Sensing technology Co. LtdZhejiangPeople’s Republic of China Management Engineering department Hebei Vocational College of Rail TransportationHebeiPeople’s Republic of China Academy of Army Armored Forces BeijingPeople’s Republic of China

Flood visualization is an effective and intuitive tool for representing flood information from abstract spatiotemporal *** the growing demand for flood disaster visualizations and mitigation,augmented flood visualizations that support decision makers’perspectives are needed,which can be enhanced by emerging augmented reality(AR)and 3D printing *** paper proposes an innovative flood AR visualization method based on a 3D-printed terrain model and investigates essential techniques,such as the suitable size calculation of the terrain models,the adaptive processing of flood data,and hybridizing virtual flood and terrain models.A prototype experimental system(PES)based on the proposed method and a comparison experimental system(CES)based on a virtual terrain are developed to conduct comparative experiments,which combine the system performance and questionnaire method to evaluate the efficiency and usability of the proposed *** statistical results indicate that the method is useful for assisting participants in understanding the flood hazard and providing a more intuitive and realistic visual experience compared with that of the traditional AR flood visualization *** frame rate is stable at 60 frames per second(FPS),which means that the proposed method is more efficient than the traditional AR flood visualization method.

关键词： Flood visualization augmented reality 3Dprinted terrain virtual geographic environment augmented reality geovisualization

Solution to an Extremal Problem on Bigraphic Pairs with a Z3-connected Realization

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2017年第8期33卷 1131-1153页

作者： Jian Hua yin Xiang Yu DAI department of mathematics College of Information Science and TechnologyHainan UniversityHaikou 570228P.R.China

Let S = （a1,...,am;b1,...,bn）, where a1,...,am and b1,...,bn are two nonincreasing sequences of nonnegative integers. The pair S= （a1,..., am; b1,..., bn） is said to be a bigraphic pair if there is a simple bipartite graph G = （X ∪ Y, E） such that a1,…, am and b1,..., bn are the degrees of the vertices in X and Y, respectively. Let Z3 be the cyclic group of order 3. Define σ（Z3, m, n） to be the minimum integer k such that every bigraphic pair S = （a1,..., am; b1,..., bn） with am, b ≥ 2 and σ（S） = a1 ＋ ... ＋ am ≥ k has a Z3-connected realization. For n = m, yin [Discrete Math., 339, 2018-2026 （2016）] recently determined the values of σ（Z3,m,m） for m ≥ 4. In this paper, we completely determine the values of σ（Z3, m, n） for m ≥ n ≥4.

关键词： Bigraphic pair Z3-connected realization group connectivity

The Threshold for the Erdos,Jacobson and Lehel Conjecture to Be True

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2006年第4期22卷 1133-1138页

作者： Jiong Sheng LI Jian Hua yin department of mathematics University of Science and Technology of China Hefei 230026 P. R. China department of Applied mathematics College of Information Science and Technology Hainan University Haikou 570228 P. R. China

Let σ（k, n） be the smallest even integer such that each n-term positive graphic sequence with term sum at least σ（k, n） can be realized by a graph containing a clique of k ＋ 1 vertices. Erdos et al. （Graph Theory, 1991, 439-449） conjectured that σ（k, n） = （k - 1）（2n- k）＋ 2. Li et al. （science in china, 1998, 510-520） proved that the conjecture is true for k 〉 5 and n ≥ （k2）＋ 3, and raised the problem of determining the smallest integer N（k） such that the conjecture holds for n ≥ N（k）. They also determined the values of N（k） for 2 ≤ k ≤ 7, and proved that [5k-1/2] ≤ N（k） ≤ （k2）＋ 3 for k ≥ 8. In this paper, we determine the exact values of σ（k, n） for n ≥ 2k＋3 and k ≥ 6. Therefore, the problem of determining σ（k, n） is completely solved. In addition, we prove as a corollary that N（k） -= [5k-1/2] for k ≥6.

关键词： Graph Degree sequence Potentially Kk+1-graphic sequence