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Exponential stabilization is studied for reaction-diffusion systems (RDSs) with a reaction term satisfying the global Lipchitz condition by means of intermittent boundary control. First, a state-dependent intermittent boundary controller is designed when system states are available. By employing the spatial integral functional method and Poincares inequality, a sufficient condition ensuring exponential stability of RDSs is presented. Then, an observer is presented to estimate the system states based on boundary output, when the information of system states is not fully accessible. An observer-based intermittent boundary controller is provided aiming to stabilize the considered RDSs based on the designed observer. Furthermore, a robust observer-based intermittent boundary controller is proposed to ensure the exponential stability for RDSs with uncertainties. Examples are given to illustrate the effectiveness of obtained theoretical results.

This study investigated the effect of adult associated cues of the multicolored Asian ladybird Harmonia axyridis Pallas (Coleoptera: Coccinellidae) on the foraging behavior of the aphid parasitoid, Aphidius gifuensis Ashmead (Hymenoptera: Aphididae) with three assays: 1) whole aphid leaf-disc with H. axyridis tracks; 2) aphid leaf-disc with only half contaminated with H. axyridis tracks; 3) aphid leaf-discs without H. axyridis tracks. Foraging behavior of A. gifuensis was recorded using the Observer® XT 11 and EthoVsion® XT 12. In addition, functional responses of A. gifuensis in patches with or without H. axyridis cues were also tested. Aphidius gifuensis females preferred oviposition in arenas where no adult tracks of H. axyridis were present. However, no significant difference between functional responses of A. gifuensis foraging in plants with and without H. axyridis cues was detected. Our study suggests that H. axyridis associated cues could influence the foraging behavior and activity of A. gifuensis under laboratory conditions. On the other hand, the foraging efficiency of A. gifuensis was not significantly affected by H. axyridis walking tracks in a single plant system. Aphidius gifuensis might exhibit flexible behavioral responses to predator associated cues. The risk of intraguild interactions and the possibility of mitigating such risks for parasitoids are important components for ultimately determining the compatibility of biological control agents.

This paper proposes a fault detection and diagnosis (FDD) approach to the nonlinear model of the intensified heat exchanger system locally and globally. It implements the optimal performances monitoring on both internal dynamics of each component and the global system. FDD of the actuator is triggered once faults occur. The recognition of cause and effect relationship between unexpected temperature behaviour and internal variables of the faulty control valves are investigated. Simulations are considered to confirm the effectiveness of the proposed strategy.

With the wide range of applications of the Internet and the rapid development of the communication technology, GPRS technology with its always-online, high access speed, high transfer rate and data traffic accounting, quickly becomes a hot research field of sensor networks connected to the Internet and exchanged the data. This paper based on technologies above, with the design of the GPRS module and the management system of a wireless meter reading system for background, makes a research on the date transmission, the transmission format and the transmission method using the GPRS DTU (Data Terminal Unit) in sensor networks. Then, we design a novel remote GPRS heat meter reading system. This system can realize the coordinated and unified management, remote control of dispersed households heat meter in the city. Finally, the interoperability of sensor networks and the Internet are achieved.

This paper presents an improved quantitative index and its solving method for analyzing relative localness of electromechanical oscillation mode, which has the advantages of computational efficiency and practicality compared to the traditional indicator. At first the eigenvalue analysis may be implemented based on small-signal model. And the exponent parameter could be subsequently optimized in the closed interval of participation factors employing the dichotomy. Eventually the index can be obtained according to those normalized factors for a mode. The case studies have been carried out on a Kundur 4-machine and 11-bus system and an IEEE 50-machine and 145-bus system by the PST simulation tool package in MATLAB environment, and the results show the effectiveness and adaptability of the presented index.

This paper deals with the problem of actuator fault diagnosis for a class of interconnected invertible nonlinear systems. For that, the actuator is viewed as an independent dynamic subsystem in series with the plant dynamic subsystem, thus forming an interconnected system. The invertibility of the interconnected system in both normal and fault models is investigated. An interconnected observer is proposed to monitor the performance of the interconnected system and provide fault information of the actuator subsystem. Then a local fault filtering algorithm is triggered to identify the root faulty parameter causing the detected actuator fault. According to the real situation of the industry, it is assumed that the output of the actuator is not available for measurement and should be reconstructed by the global output of the interconnected system. A method capable of supervising the actuator subsystem at both local and global levels is provided.

This paper presents an alternative method for estimating coherence of Inter-Area Oscillation(IAO) mode using Enhanced Empirical Mode Decomposition(E-EMD) technique and Correlation analysis(CA). It firstly extracts the components associated with the objective inter-area modes from each tie-line active power signal by utilizing the E-EMD techniques. Then the cross-correlation coefficients resulted from correlation analysis of these time-domain components are used to determine the coherence indexes among groups or generators for the IAO modes. This proposed method is more intuitive than spectral correlation analysis for demonstrating the phase relationship. A random time-varying load model is established by the Python programming tool of PSS/E in order to simulate the operating environment in the real world. The case studies have been carried out on New England 39-bus system and a simplified system of Southeastern Australian power system, and the results show that the proposed algorithm is effective.

National audience; With the development of science and technology, the industrialization process continues to speed up. The demand for the safety of modern giant systems grows very fast, too. As key research directions to improve the reliability and safety of dynamic systems, fault diagnosis and fault tolerant control (FTC) methods have received more and more attention. Though very rich results have been achieved in these directions during the past decades, fault diagnosis and fault-tolerant control theory still seem to be weak when facing high nonlinear complex industrial systems that iterate even faster.Otherwise, the most advanced creations of science and technology like space shuttles, and civil air-crafts, would not encounter disasters like explosions or crashes. Therefore, fault diagnosis and FTC theories must keep pace with the fast-changing world to ensure safety and stability.In this thesis, we did some extensions to the multiple model approach based fault tolerant control method and proposed several fault diagnosis and FTC algorithms based on model matching strategies. This is under the consideration of designing FTC strategies for complex nonlinear systems using simple ideas and logic. Specifically, the multiple model approach is first used to represent the complex system by a set of simple models. The classical multiple model approach is then extended by increasing its dimensions to create a system that can adapt to different faulty conditions. This results in a multi-dimensional multiple model set that can be adapted to the real system in normal states or under faults. The corresponding multi-dimensional controller bank is designed according to the parameters of the local models. Since the local models are generally set as linear ones, their controllers can be designed easily.When the multi-dimensional multiple model set is constructed, two model matching fault tolerant strategies are proposed. For the traditional system, its output is compared with the model set to determine the interval in which the system is located, and then the controllers, corresponding to the sub-models which are matched to the current system, can be selected to conduct the control calculation. For the controller bank scheduling part, the classical switching or mixing strategy can be used. When using the mixing strategy, the weighted sum of the multi-controller outputs represents the output of the controller bank. The weighting values also have a relatively large research space. They can be linearly weighted, non-linearly weighted, or selectively weighted. Such an integrated output can also be performed in two dimensions, e.g., within one controller set and between fault tolerant controller sets.Inspired by the concept of adaptive model, a two-layer multiple model structure is used as the basic framework to conduct the FTC strategy. In the actual operation, the pre-defined local models set is like a source pool. Parameters of the interval vertex models selected from the multi-dimensional multiple model set that encloses the actual system are used to initiate the adaptive models to approximate the actual system with unknown parameters. In this way, it achieves the purpose of controlling the unknown system while identifying it. A fault diagnosis module monitors the actual system in real time and determines its operating interval within the two-layer multiple model set.When a big change is detected, it indicates a fault. The fault information is transmitted to the fault tolerant module, which initiates an adaptation process to match the actual system according to the new vertex models parameter. Here, an extra controller is set to the reference model in this process to achieve the control goal by following the original reference while the adaptation process approximating the actual system. Several simulations demonstrate the effectiveness of the proposed model matching FTC strategy for different systems and are worthy of promotions and further study.; Avec le développement de la science et de la technologie, le processus d’industrialisation continue de s’accélérer. La demande de sécurité des systèmes géants modernes augmente également très rapidement. En tant qu’axes de recherche clés pour améliorer la fiabilité et la sécurité des systèmes dynamiques, le diagnostic des fautes (FD) et les méthodes de la commande tolérante aux fautes (FTC) ont reçu de plus en plus d’attention. Bien que des résultats très probants ont été obtenus dans ces directions au cours des dernières décennies, la théorie du diagnostic des fautes et de la commande tolérante aux fautes semblent encore insuffisants face aux problèmes rencontrés lors de la commande des systèmes industriels complexes non linéaires de grande taille. Par conséquent, les études concernant le diagnostic des défauts et les théories de FTC doivent continuer à se développer pour garantir la sécurité et la stabilité des systèmes industriels.Dans cette thèse, nous avons fait quelques extensions à la méthode de FTC basée sur l’approche des modèles multiples et nous avons proposé plusieurs algorithmes de diagnostic de fautes et de FTC basés sur des stratégies de correspondance de modèles. Ceci dans le but de concevoir des stratégies FTC pour des systèmes non linéaires complexes en utilisant des idées et des logiques simples. Plus précisément, l’approchemulti-modèles est d’abord utilisée pour représenter le système complexe par un ensemble de modèles simples. L’approche classique des modèles multiples est ensuite étendue en augmentant ses dimensions pour créer un système qui peut s’adapter à différentes situations de défaillance. On obtient ainsi un ensemble de modèles multidimensionnels qui peuvent être adaptés au système réel dans des états normaux ou en cas de défaillance. La banque de contrôleurs multidimensionnelle correspondante est conçue en fonction des paramètres des modèles locaux. Comme les modèles locaux sont généralement linéaires, leurs contrôleurs peuvent être conçus facilement.Lorsque l’ensemble de modèles multiples multidimensionnels est construit, deux stratégies de commande tolérance aux fautes sont proposées. La sortie du système est comparée à l’ensemble de modèles pour déterminer l’intervalle dans lequel se trouve le système, puis les contrôleurs, correspondants aux sous-modèles du système actuel, peuvent être sélectionnés pour effectuer le calcul de la commande. Pour la partie planification de la banque de contrôleurs, la stratégie classique de commutation ou de mélange peut être utilisée. En cas d’utilisation de la stratégie de mélange, la somme pondérée des sorties des multicontrôleurs représente la sortie de la banque de contrôleurs. Les valeurs de pondération ont également un espace de recherche relativement large. Elles peuvent être pondérées linéairement, non linéairement ou sélectivement. Une telle sortie intégrée peut également être réalisée en deux dimensions, par exemple, au sein d’un ensemble de contrôleurs et entre des ensembles de contrôleurs tolérants aux fautes.Inspiré par le concept de modèle adaptatif, une approche multi-modèles à deux couches est utilisée comme base pour développer la stratégie FTC. Les paramètres des modèles sélectionnés dans l’ensemble de modèles multiples multidimensionnels qui représentent les paramètres des modèles intégrés dans l’ensemble de modèles multidimensionnels multiples qui représentent le système réel sont utilisés pour initier les modèles adaptatifs afin de se rapprocher du système réel avec des paramètres inconnus. Le système réel est utilisé pour lancer les modèles adaptatifs pour se rapprocher du système réel avec des paramètres inconnus. De cette manière, on peut atteindre l’objectif du contrôle du système en identifiant ses paramètres. Un module de diagnostic de défauts permet la surveillance du système en temps réel et détermine son domaine de fonctionnement dans l’ensemble de modèles multiples à deux couches est conçu.Lorsqu’un changement important est détecté, le bloc du diagnostic indique un défaut. L’information sur le défaut est transmise au module de la commande tolérante aux fautes, qui lance un processus d’adaptation pour faire correspondre le système réel aux paramètres des nouveaux modèles. Dans cette situation, un contrôleur supplémentaire est défini pour corriger et atteindre l'objectif du contrôle. Plusieurs simulations démontrent l’efficacité de la stratégie FTC d’adaptation de modèle proposée pour différents systèmes.