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3D tomographic analysis of equatorial plasma bubble using GNSS-TEC data from Indonesian GNSS Network

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Earth and Planetary Physics 2025年第1期9卷 127-136页

作者： Ihsan Naufal Muafiry Prayitno Abadi Teguh N.Pratama Dyah R.Martiningrum Sri Ekawati Yuandhika GWismaya Febrylian FChabibi Gatot HPramono Research Center for Climate and Atmosphere Indonesian National Research and Innovation Agency(BRIN)BandungIndonesia Indonesian Geospatial information Agency(BIG) JakartaIndonesia Dept.of Physics Faculty of ScienceUniversiti Teknologi MalaysiaJohor BahruMalaysia Dept.Earth Planet Sci. Hokkaido UniversitySapporoJapan School of electrical engineering Telkom UniversityBandungIndonesia

Equatorial Plasma Bubbles(EPBs)are ionospheric irregularities that take place near the magnetic *** most commonly occur after sunset during the equinox months,although they can also be observed during other *** phenomenon significantly disrupts radio wave signals essential to communication and navigation *** national network of Global Navigation Satellite System(GNSS)receivers in Indonesia(>30°longitudinal range)provides an opportunity for detailed EPB *** explore this,we conducted preliminary 3D tomography of total electron content(TEC)data captured by GNSS receivers following a geomagnetic storm on December 3,2023,when at least four EPB clusters occurred in the Southeast Asian *** and extracted TEC depletion with a 120-minute running average were then used as inputs for a 3D tomography *** 2D spatial distribution consistently captured the four EPB clusters over *** tomography results were validated through a classical checkerboard test and comparisons with other ionospheric data sources,such as the Global Ionospheric Map(GIM)and International Reference Ionosphere(IRI)*** of the results demonstrates the capability of the Indonesian GNSS network to measure peak ionospheric *** findings highlight the potential for future three-dimensional research of plasma bubbles in low-latitude regions using existing GNSS networks,with extensive longitudinal coverage.

关键词： EPB Indonesian GNSS Network 3D tomography

Cryptanalysis on an image block encryption algorithm based on spatiotemporal chaos

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Chinese Physics B 2012年第6期21卷 77-83页

作者：王兴元何国祥 faculty of Electronic information and electrical engineering Dalian University of Technology

An image block encryption scheme based on spatiotemporal chaos has been proposed recently. In this paper, we analyse the security weakness of the proposal. The main problem of the original scheme is that the generated keystream remains unchanged for encrypting every image. Based on the flaws, we demonstrate a chosen plaintext attack for revealing the equivalent keys with only 6 pairs of plaintext/ciphertext used. Finally, experimental results show the validity of our attack.

关键词： encryption spatiotemporal chaos chosen plaintext attack equivalent keys

A novel image block cryptosystem based on a spatiotemporal chaotic system and a chaotic neural network

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Chinese Physics B 2013年第5期22卷 232-240页

作者：王兴元鲍雪梅 faculty of Electronic information and electrical engineering Dalian University of Technology

In this paper, we propose a novel block cryptographic scheme based on a spatiotemporal chaotic system and a chaotic neural network （CNN）. The employed CNN comprises a 4-neuron layer called a chaotic neuron layer （CNL）, where the spatiotemporal chaotic system participates in generating its weight matrix and other parameters. The spatiotemporal chaotic system used in our scheme is the typical coupled map lattice （CML）, which can be easily implemented in parallel by hard- ware. A 160-bit-long binary sequence is used to generate the initial conditions of the CML. The decryption process is symmetric relative to the encryption process. Theoretical analysis and experimental results prove that the block cryptosys- tem is secure and practical, and suitable for image encryption.

关键词： image encryption block cryptosystem chaotic neural network coupled map lattice

An efficient adaptive arithmetic coding image compression technology

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Chinese Physics B 2011年第10期20卷 239-245页

作者：王兴元云娇娇张永雷 faculty of Electronic information and electrical engineering Dalian University of Technology

This paper proposes an efficient lossless image compression scheme for still images based on an adaptive arithmetic coding compression algorithm. The algorithm increases the image coding compression rate and ensures the quality of the decoded image combined with the adaptive probability model and predictive coding. The use of adaptive models for each encoded image block dynamically estimates the probability of the relevant image block. The decoded image block can accurately recover the encoded image according to the code book information. We adopt an adaptive arithmetic coding algorithm for image compression that greatly improves the image compression rate. The results show that it is an effective compression technology.

关键词： arithmetic coding adaptive image compression

Impulsive synchronisation of a class of fractional-order hyperchaotic systems

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Chinese Physics B 2011年第3期20卷 88-94页

作者：王兴元张永雷林达张娜 faculty of Electronic information and electrical engineering Dalian University of Technology

In this paper, an impulsive synchronisation scheme for a class of fractional-order hyperchaotic systems is proposed. The sufficient conditions of a class of integral-order hyperchaotic systems＇ impulsive synchronisation are illustrated. Furthermore, we apply the sufficient conditions to a class of fractional-order hyperchaotic systems and well achieve impulsive synchronisation of these fractional-order hyperchaotic systems, thereby extending the applicable scope of impulsive synchronisation. Numerical simulations further demonstrate the feasibility and effectiveness of the proposed scheme.

关键词： hyperchaotic systems fractional-order hyperchaotic systems impulsive synchronization

A new perturbation method to the Tent map and its application

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Chinese Physics B 2011年第5期20卷 191-198页

作者：王兴元王林林 faculty of Electronic information and electrical engineering Dalian University of Technology

Disturbance imposed on the chaotic systems is an effective way to maintain its chaotic good encryption features. This paper proposes a new perturbation method to the Tent map. First it divides the Tent map domain into 2N parts evenly and selects a particular part from them, then proliferates the Tent map mapping trajectory of this particular part, which can disturb the entire system disturbance. The mathematical analysis and simulated experimental results prove that the disturbed Tent map has uniform invariant distribution and can produce good cryptographic properties of pseudo-random sequence. These facts avoid the phenomenon of short-period caused by the computer＇s finite precision and reducing the sequence＇s dependence on the disturbance signal, such that effectively compensate for the digital chaotic system dynamics degradation.

关键词： perturbation Tent degradation chaotic

A fast image encryption algorithm based on only blocks in cipher text

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Chinese Physics B 2014年第3期23卷 165-172页

作者：王兴元王倩 faculty of Electronic information and electrical engineering Dalian University of Technology

In this paper, a fast image encryption algorithm is proposed, in which the shuffling and diffusion is performed simul- taneously. The cipher-text image is divided into blocks and each block has k x k pixels, while the pixels of the plain-text are scanned one by one. Four logistic maps are used to generate the encryption key stream and the new place in the cipher image of plain image pixels, including the row and column of the block which the pixel belongs to and the place where the pixel would be placed in the block. After encrypting each pixel, the initial conditions of logistic maps would be changed ac- cording to the encrypted pixel＇s value; after encrypting each row of plain image, the initial condition would also be changed by the skew tent map. At last, it is illustrated that this algorithm has a faster speed, big key space, and better properties in withstanding differential attacks, statistical analysis, known plaintext, and chosen plaintext attacks.

关键词： image encryption shuffle and diffuse simultaneously block cipher logistic map

An improved fast fractal image compression using spatial texture correlation

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Chinese Physics B 2011年第10期20卷 228-238页

作者：王兴元王远星云娇娇 faculty of Electronic information and electrical engineering Dalian University of Technology

This paper utilizes a spatial texture correlation and the intelligent classification algorithm （ICA） search strategy to speed up the encoding process and improve the bit rate for fractal image compression. Texture features is one of the most important properties for the representation of an image. Entropy and maximum entry from co-occurrence matrices are used for representing texture features in an image. For a range block, concerned domain blocks of neighbouring range blocks with similar texture features can be searched. In addition, domain blocks with similar texture features are searched in the ICA search process. Experiments show that in comparison with some typical methods, the proposed algorithm significantly speeds up the encoding process and achieves a higher compression ratio, with a slight diminution in the quality of the reconstructed image; in comparison with a spatial correlation scheme, the proposed scheme spends much less encoding time while the compression ratio and the quality of the reconstructed image are almost the same.

关键词： fractal image compression texture features intelligent classification algorithm spatialcorrelation

Synchronization of spatiotemporal chaotic systems and application to secure communication of digital image

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Chinese Physics B 2011年第2期20卷 125-132页

作者：王兴元张娜任小丽张永雷 faculty of Electronic information and electrical engineering Dalian University of Technology

Coupled map lattices （CMLs） are taken as examples to study the synchronization of spatiotemporal chaotic systems. In this paper, we use the nonlinear coupled method to implement the synchronization of two coupled map lattices. Through the appropriate separation of the linear term from the nonlinear term of the spatiotemporal chaotic system, we set the nonlinear term as the coupling function and then we can achieve the synchronization of two coupled map lattices. After that, we implement the secure communication of digital image using this synchronization method. Then, the discrete characteristics of the nonlinear coupling spatiotemporal chaos are applied to the discrete pixel of the digital image. After the synchronization of both the communication parties, the receiver can decrypt the original image. Numerical simulations show the effectiveness and the feasibility of the proposed program.

关键词： coupled map lattice projective synchronization digital image secure communication