Chaos-based communication scheme using proportional and proportional-integral observers

In this paper, we propose a new chaos-based communication scheme using the observers. The novelty lies in the masking procedure that is employed to hide the confidential information using the chaotic oscillator. We use a combination of the addition and inclusion methods to mask the information. The performance of two observers, the proportional observer (P-observer) and the proportional integral observer (PI-observer) is compared that are employed as receivers for the proposed communication scheme. We show that the P-observer is not suitable scheme since it imposes unpractical constraints on the messages to be transmitted. On the other hand, we show that the PI-observer is the better solution because it allows greater flexibility in choosing the gains of the observer and does not impose any unpractical restrictions on the message

High gain observer for structured multi-output nonlinear systems

In this note, we present two system structures that characterize classes of multi-input multi-output uniformly observable systems. The first structure is decomposable into a linear and a nonlinear part while the second takes a more general form. It is shown that the second system structure, being more general, contains several system structures that are available in the literature. Two high gain observer design methodologies are presented for both structures and their distinct features are highlighted

Using discrete-time hyperchaotic-based asymmetric encryption and decryption keys for secure signal transmission

In this paper, a framework for the synchronization of two non-identical discrete-time hyperchaotic systems, namely the 3D Baier-Klein and the 3D Hitzel-Zele maps, based on the use of hybrid output feedback concept and aggregation techniques, is employed to design a two-channel secure communication system. New sufficient conditions for synchronization are obtained by the use of Borne and Gentina practical criterion for stabilization study associated to the forced arrow form matrix for system description. The efficiency of the proposed approach to confidentially recover the transmitted message signal is shown via an application to the hyperchaotic Baier-Klein and Hitzel-Zele systems, considered as generators of asymmetric encryption and decryption keys

Secure communication based on indirect coupled synchronization

In this paper, a secure communication system composed of four chaotic oscillators is proposed. Two of these oscillators are unidirectionally coupled and employed as transmitter and receiver. The other two oscillators are indirectly coupled and are employed as keystream generators. The novelty lies in the generation of the same chaotic keystream both in the transmitter and receiver side for encryption and decryption purposes. We show, in particular, that it is possible to synchronize the two keystream generators even though they are not directly coupled. So doing, an estimation of the keystream is obtained allowing decrypting the message. The main feature of the proposed communication scheme is that the keystream cannot be generated with the sole knowledge of the transmitted chaotic signal, hence making it very secure. The performance of the proposed communication scheme is shown via simulation using the Chua and Lorenz oscillators

Fast-individual-harmonic-extraction technique

One outcome of a PhD project (C H Ng, University studentship) A collaborative work (the Energy Systems Group, Northumbria and Durham University). It deals with the problem of harmonic suppression or elimination in power systems for safety and power quality purposes. The speed of harmonic extraction being is a crucial issue in power systems to avoid damage of electrical equipments. Traditionally, harmonic suppression is done via Fourier transform. The main originality of this paper is on the use of a fast harmonic extraction algorithm, which is six times faster than traditional harmonic extraction techniques

Implementation of a secure digital chaotic communication scheme on a DSP board

In this paper, a new a secure communication scheme using chaotic signal for transmitting binary digital signals is proposed and which is then implemented on a Digital Signal Processor (DSP) board. The method uses the idea of indirect coupled synchronization for generating the same keystream in the transmitter and receiver side. This chaotic keystream is applied to encrypt the message signal before being modulated with a chaotic carrier generated from the transmitter. Discrete chaotic maps, 3D Henon map and Lorenz system are used as transmitter/receiver and key generators respectively. The overall system is experimentally implemented in the TMS320C6713 DSK board using code composer and Simulink showing the successful message extraction thus proving the feasibility of the system in the DSP board

Fundamental issues in antenna design for microwave medical imaging applications

This paper surveys the development of microwave medical imaging and the fundamental challenges associated with microwave antennas design for medical imaging applications. Different microwave antennas used in medical imaging applications such as monopoles, bow-tie, vivaldi and pyramidal horn antennas are discussed. The challenges faced when the latter used in medical imaging environment are detailed. The paper provides the possible solutions for the challenges at hand and also provides insight into the modelling work which will help the microwave engineering community to understand the behaviour of the microwave antennas in coupling media

Discrete-time synchronization of chaotic systems for secure communication

This paper deals with the problem of designing an exact nonlinear reconstructor for discrete-time chaotic encrypted messages. More precisely, we investigate the problem of designing a discrete-time dead-beat observer for nonlinear systems with unknown inputs. The application of the proposed observer in the context of secure communication and data transmission is also investigated

Fouling Detection in Heat Exchangers

This paper deals with the design of a nonlinear observer for the purpose of detecting the fouling phenomenon that commonly occurs in heat exchangers. First, the general model of the heat exchanger is presented in terms of partial differential equations. Next, a simplified lump model is derived that is suitable for the observer design. The observer gains are generated by using appropriate Lyapunov functions, equations and inequalities

Flows consumption assessment study for fuel cell vehicles: Towards a popularization of FCVs technology

Climate change can be caused by a major part from the high fossil fuel usage and consumption in transportation field. It contributes to the increase of pollutant emissions, which lead to serious problems on human health in addition to the environmental degradation phenomena. Hydrogen fuel cell vehicles (FCVs) are expected to have a significant impact in meeting both energy security and environmental concerns globally. Starting for the premise that public acceptance and attitudes studies were generally positive towards hydrogen and fuel cells vehicles, even if the public knows few things about this technology; authors then got the idea to present a simplified scientific work dealing with the description of the energy management and flows calculations on board FCVs. This work aims not only to the popularization of this technology but also to outreach people about its sustainable character. A variable driving profile is adopted with a total distance of 1 km with duration of 60 s. The total hydrogen amount consumed is 1,34 g km−1. Under pressure, only 5 kg of hydrogen give optimal autonomy of 700 km, which is really competitive to the conventional gasoline cars. A nice advantage is yet observed and its concerns the environmental profits