This paper analyzes the problems in image encryption and decryption based on chaos theory. This article introduces the application of the two-stage Logistic algorithm in image encryption and decryption, then by inform...This paper analyzes the problems in image encryption and decryption based on chaos theory. This article introduces the application of the two-stage Logistic algorithm in image encryption and decryption, then by information entropy analysis it is concluded that the security of this algorithm is higher compared with the original image;And a new image encryption and decryption algorithm based on the combination of two-stage Logistic mapping and <i>M</i> sequence is proposed. This new algorithm is very sensitive to keys;the key space is large and its security is higher than two-stage Logistic mapping of image encryption and decryption technology.展开更多
In many applications, it is necessary to transmit images at a remote station, where wired Internet service is not available. In this case, wireless local loop (WLL) can help in making wireless link between one end nod...In many applications, it is necessary to transmit images at a remote station, where wired Internet service is not available. In this case, wireless local loop (WLL) can help in making wireless link between one end node of the internet and remote service center. In such link, the communication is heavily affected by large and small scale fading;hence the received signal experiences huge distortion in case of forward error correction. Otherwise, huge service delay arises due to frequent negative acknowledgements. To combat the situation, we can choose Alamouti channel of full rate and fully orthogonal space-time block code (OSTBC). Our aim is to transmit images through Alamouti channel and to observe the quality of the recovered image, in context of bit error rate (BER). We have also observed the impact of fading and additive white Gaussian noise (AWGN) on the image without application of error correction or detection technique of channel coding. To ensure security, we apply the RSA algorithm on each pixel prior transmitting and decrypt them at the receiving end, where we found no impairment from the algorithm. Finally, we observe that the relative performance of the system changes digital modulation schemes.展开更多
For complex-valued or quaternionic neural networks,scholars and researchers usually decompose them into real-valued systems.The decomposed real-valued systems are equiv-alent to original systems.Then,the dynamical beh...For complex-valued or quaternionic neural networks,scholars and researchers usually decompose them into real-valued systems.The decomposed real-valued systems are equiv-alent to original systems.Then,the dynamical behaviors of real-valued systems obtained are investigated,including stability,synchronization,and chaos etc.In this paper,a class of quaternionic neural networks with time-varying delays is investigated.First,by designing a suitable PI controller,synchronization of the considered chaotic system is realized.By using a non-decomposition method and structuring a novel Lyapunov functional,sufficient conditions are derived to guarantee synchronization between the drive-response systems.It is worth mentioning that,unlike other methods,our approach does not require break-ing down the quaternionic neural networks into four separate real-valued systems.Fur-thermore,we demonstrate the practical application of these chaotic quaternionic neural networks with time-varying delays in image encryption and decryption.Based on one se-quence of chaotic signal from state trajectory of single quaternion-valued neuron and a new encryption algorithm,the application of chaotic system proposed,that is,image encryp-tion,is researched.The process of image decryption is simply the reverse of the encryption process.Finally,numerical simulation examples are provided to validate the effectiveness of the designed PI controller and performance of image encryption and decryption.展开更多
文摘This paper analyzes the problems in image encryption and decryption based on chaos theory. This article introduces the application of the two-stage Logistic algorithm in image encryption and decryption, then by information entropy analysis it is concluded that the security of this algorithm is higher compared with the original image;And a new image encryption and decryption algorithm based on the combination of two-stage Logistic mapping and <i>M</i> sequence is proposed. This new algorithm is very sensitive to keys;the key space is large and its security is higher than two-stage Logistic mapping of image encryption and decryption technology.
文摘In many applications, it is necessary to transmit images at a remote station, where wired Internet service is not available. In this case, wireless local loop (WLL) can help in making wireless link between one end node of the internet and remote service center. In such link, the communication is heavily affected by large and small scale fading;hence the received signal experiences huge distortion in case of forward error correction. Otherwise, huge service delay arises due to frequent negative acknowledgements. To combat the situation, we can choose Alamouti channel of full rate and fully orthogonal space-time block code (OSTBC). Our aim is to transmit images through Alamouti channel and to observe the quality of the recovered image, in context of bit error rate (BER). We have also observed the impact of fading and additive white Gaussian noise (AWGN) on the image without application of error correction or detection technique of channel coding. To ensure security, we apply the RSA algorithm on each pixel prior transmitting and decrypt them at the receiving end, where we found no impairment from the algorithm. Finally, we observe that the relative performance of the system changes digital modulation schemes.
基金funded by the Scientific Research Program Funded by the Shaanxi Provincial Education Department(Grant No.23JK0550)by the Natural Science Basic Research Program of Shaanxi Province(Grant Nos.2024JC-YBQN-0726,2024JCYBMS-352 and 2023-JC-QN-0001)+2 种基金by the Qin Chuangyuan"Scientists+Engineers"Team Construction in Shaanxi Province(Grant No.2022KXJ-38)by the Xi'an Science and Technology Program(Grant No.2022JH-RGZN-0041)by the Xi'an Science and Technology Program(Grant No.23ZDCYJSGG0025-2022).
文摘For complex-valued or quaternionic neural networks,scholars and researchers usually decompose them into real-valued systems.The decomposed real-valued systems are equiv-alent to original systems.Then,the dynamical behaviors of real-valued systems obtained are investigated,including stability,synchronization,and chaos etc.In this paper,a class of quaternionic neural networks with time-varying delays is investigated.First,by designing a suitable PI controller,synchronization of the considered chaotic system is realized.By using a non-decomposition method and structuring a novel Lyapunov functional,sufficient conditions are derived to guarantee synchronization between the drive-response systems.It is worth mentioning that,unlike other methods,our approach does not require break-ing down the quaternionic neural networks into four separate real-valued systems.Fur-thermore,we demonstrate the practical application of these chaotic quaternionic neural networks with time-varying delays in image encryption and decryption.Based on one se-quence of chaotic signal from state trajectory of single quaternion-valued neuron and a new encryption algorithm,the application of chaotic system proposed,that is,image encryp-tion,is researched.The process of image decryption is simply the reverse of the encryption process.Finally,numerical simulation examples are provided to validate the effectiveness of the designed PI controller and performance of image encryption and decryption.
