Biblio

The rapid development of network information technology, individual’s information networks security has become a very critical issue in our daily life. Therefore, it is necessary to study the malware propagation model system. In this paper, the traditional integer order malware propagation model system is extended to the field of fractional-order. Then we analyze the asymptotic stability of the fractional-order malware propagation model system when the equilibrium point is the origin and the time delay is 0. Next, the asymptotic stability and bifurcation analysis of the fractional-order malware propagation model system when the equilibrium point is the origin and the time delay is not 0 are carried out. Moreover, we study the asymptotic stability of the fractional-order malware propagation model system with an interior equilibrium point. In the end, so as to verify our theoretical results, many numerical simulations are provided.

When we are express our internal status, such as emotions, the human body expression we use follows the compositionality principle. It is a theory in linguistic which proposes that the single components of the bodily presentation as well as the rules used to combine them are the major parts to finish this process. In this paper, such principle is applied to the process of expressing and recognizing emotional states through body expression, in which certain key features can be learned to represent certain primitives of the internal emotional state in the form of basic variables. This is done by a hierarchical recurrent neural learning framework (RNN) because of its nonlinear dynamic bifurcation, so that variables can be learned to represent different hierarchies. In addition, we applied some adaptive learning techniques in machine learning for the requirement of real-time emotion recognition, in which a stable representation can be maintained compared to previous work. The model is examined by comparing the PB values between the training and recognition phases. This hierarchical model shows the rationality of the compositionality hypothesis by the RNN learning and explains how key features can be used and combined in bodily expression to show the emotional state.

Generalized chaos systems have more complex dynamic behavior than conventional chaos systems. If a generalized response system can be synchronized with a conventional drive system, the flexible control parameters and unpredictable synchronization state will increase significantly. The study first constructs a four-dimensional nonlinear dynamic equation with quadratic variables as a drive system. The numerical simulation and analyses of the Lyapunov exponent show that it is also a chaotic system. Based on the generalized chaos synchronization (GCS) theory, a four-dimensional diffeomorphism function is designed, and the corresponding GCS response system is generated. Simultaneously, the structural and synchronous circuits of information interaction and control are constructed with Multisim™ software, with the circuit simulation resulting in a good agreement with the numerical calculations. In order to verify the practical effect of generalized synchronization, an RGB digital image secure communication scheme is proposed. We confuse a 24-bit true color image with the designed GCS system, extend the original image to 48-bits, analyze the scheme security from keyspace, key sensitivity and non-symmetric identity authentication, classical types of attacks, and statistical average from the histogram, image correlation. The research results show that this GCS system is simple and feasible, and the encryption algorithm is closely related to the confidential information, which can resist the differential attack. The scheme is suitable to be applied in network images or other multimedia safe communications.

In operation centers, it is important to know the power transfer limit to guarantee the safety operation of the power system. The Voltage Stability Margin (VSM) is a widely used measure and needs to definition of a load growth direction (LGD) to be computed. However, different definitions of LGD can provide different VSMs and then the VSM may not be reliable. Besides, the measure of this power transfer limit usually is related to the Saddle-Node Bifurcation. In dynamic security assessment (DSA) is highly desirable to identify limit regions where the power system can operate safely due to Hopf (HB) and Saddle-Node (SNB) Bifurcations. This paper presents a modeling of the power system incorporating the LGD variation based on participation factors to evaluate the effects on the stability margin estimation due to HB and SNB. A direct method is used to calculate the stability margin of the power system for a given load direction. The analysis was performed in the IEEE 39 bus system.

This paper presents a new fractional-order hidden strange attractor generated by a chaotic system without equilibria. The proposed non-equilibrium fractional-order chaotic system (FOCS) is asymmetric, dissimilar, topologically inequivalent to typical chaotic systems and challenges the conventional notion that the presence of unstable equilibria is mandatory to ensure the existence of chaos. The new fractional-order model displays rich bifurcation undergoing a period doubling route to chaos, where the fractional order α is the bifurcation parameter. Study of the hidden attractor dynamics is carried out with the aid of phase portraits, sensitivity to initial conditions, fractal Lyapunov dimension, maximum Lyapunov exponents spectrum and bifurcation analysis. The minimum commensurate dimension to display chaos is determined. With a view to utilizing it in chaos based cryptology and coding information, a synchronisation control scheme is designed. Finally the theoretical analyses are validated by numerical simulation results which are in good agreement with the former.

In this paper a random number generation method based on a piecewise linear one dimensional (PL1D) discrete time chaotic maps is proposed for applications in cryptography and steganography. Appropriate parameters are determined by examining the distribution of underlying chaotic signal and random number generator (RNG) is numerically verified by four fundamental statistical test of FIPS 140-2. Proposed design is practically realized on the field programmable analog and digital arrays (FPAA-FPGA). Finally it is experimentally verified that the presented RNG fulfills the NIST 800-22 randomness test without post processing.

The chaotic system and cryptography have some common features. Due to the close relationship between chaotic system and cryptosystem, researchers try to combine the chaotic system with cryptosystem. In this study, security analysis of an encryption algorithm which aims to encrypt the data with ECG signals and chaotic functions was performed using the Logistic map in text encryption and Henon map in image encryption. In the proposed algorithm, text and image data can be encrypted at the same time. In addition, ECG signals are used to determine the initial conditions and control parameters of the chaotic functions used in the algorithm to personalize of the encryption algorithm. In this cryptanalysis study, the inadequacy of the mentioned process and the weaknesses of the proposed method have been determined. Encryption algorithm has not sufficient capacity to provide necessary security level of key space and secret key can be obtained with only one plaintext/ciphertext pair with chosen-plaintext attack.

To enhance the encryption and anti-translation capability of the information, we constructed a five-dimensional chaotic system. Combined with the Lü system, a time-switched system with multiple chaotic attractors is realized in the form of a digital circuit. Some characteristics of the five-dimensional system are analyzed, such as Poincare mapping, the Lyapunov exponent spectrum, and bifurcation diagram. The analysis shows that the system exhibits chaotic characteristics for a wide range of parameter values. We constructed a time-switched expression between multiple chaotic attractors using the communication between a microcontroller unit (MCU) and field programmable gate array (FPGA). The system can quickly switch between different chaotic attractors within the chaotic system and between chaotic systems at any time, leading to signal sources with more variability, diversity, and complexity for chaotic encryption.