Forest ecosystems include a great variety of communities of organisms interacting with their physical environment: multi-aged natural forests, even-aged monocultures, and secondary forests invaded by foreign species. The challenge is to sustain their ability to function, by adapting to changing climates and satisfying a multitude of human demands. Our first chapter sets the scene with a discussion about the effects of forest management on ecosystem services. Details about forest observational infrastructures are introduced in the second chapter. The third chapter presents methods of analysing forest density and structure. Models for estimating the shape and growth of individual forest trees are introduced in chapter 4, models of forest community production in Chapter 5. Methods and examples of sustainable forest design are covered in chapter 6. New scientific contributions continue to emerge as we are writing, and this work is never finished. We hope to continue with regular updates replacing obsolete sections with new ones, but the general aim remains the same, to introduce a range of methods that will assist those interested in sustaining forest ecosystems.
In recent years, with increasingly frequent economic and trade cooperation between China and African countries, China has become the most important international trade partner and an important source of foreign investment for Africa. Therefore, there is room for both sides to further expand and deepen their economic and trade cooperation. The peace and security situation in Africa has always been a mixed story. On the one hand, it shoes a generally positive trend with regional conflicts, wars and other traditional security hot problems declining. On the other hand, new types of security challenges continuously emerge, and non-traditional security problems become the most serious ones. This complex security situation results from both internal and external factors, including tribalism, resource curse, long-term economic underdevelopment, severe food shortage, incapable national governance, intervention by external forces, globalization, and the amplification effect of technological advancements. Both security governance within African countries and external forces' intervention in regional peace and security affairs are manifestly characterized by militarization. Due to the military intervention by external forces, countries in the region have become more dependent on external intervention and cannot improve their own capacity of security governance, thus creating a vicious circle of conflicts-external intervention-withdrawal of external forces-recurrence of conflicts. This regional security situation exerts an obvious influence on international economic and trade cooperation. Protection of overseas interests requires the joint efforts of the Chinese government, enterprises and all sectors of the society to take corresponding measures. On the basis of previous endeavors, the Chinese government should continue strengthening cooperation with African countries in peace and security affairs. The cooperation should keep in pace with the evolution of global economic and political security patterns, meet the demand for the upgrading of China-Africa relations, conform to the altered nature of regional peace and security, and accord with the shift of concept and method of China's participation in international affairs.
Singular systems which are also referred to as descriptor systems, semi-state systems, differential- algebraic systems or generalized state-space systems have attracted much attention because of their extensive applications in the Leontief dynamic model, electrical and mechanical models, etc. This monograph presented up-to-date research developments and references on stability analysis and design of nonlinear singular systems. It investigated the problems of practical stability, strongly absolute stability, input-state stability and observer design for nonlinear singular systems and the problems of absolute stability and multi-objective control for nonlinear singularly perturbed systems by using Lyapunov stability theory, comparison principle, S-procedure and linear matrix inequality (LMI), etc. Practical stability, being quite different from stability in the sense of Lyapunov, is a significant performance specification from an engineering point of view. The basic concepts and results on practical stability for standard state-space systems were generalized to singular systems. For Lur’e type descriptor systems (LDS) which were the feedback interconnection of a descriptor system with a static nonlinearity, strongly absolute stability was defined and Circle criterion and Popov criterion were derived. The notion of input-state stability (ISS) for nonlinear singular systems was defined based on the concept of ISS for standard state-space systems and the characteristics of singular systems. LMI-based sufficient conditions for ISS of Lur’e singular systems were proposed. Furthermore, observer design for nonlinear singular systems was studied and some observer design methods were proposed by the obtained stability results and convex optimization algorithms. Finally, absolute stability and multi-objective control of nonlinear singularly perturbed systems were considered. By Lyapunov functions, absolute stability criteria of Lur’e singularly perturbed systems were proposed and multi-objective control of T-S fuzzy singularly perturbed systems was achieved. Compared with the existing results, the obtained methods do not depend on the decomposition of the original system and can produce a determinate upper bound for the singular perturbation parameter.
Forest ecosystems include a great variety of communities of organisms interacting with their physical environment: multi-aged natural forests, even-aged monocultures, and secondary forests invaded by foreign species. The challenge is to sustain their ability to function, by adapting to changing climates and satisfying a multitude of human demands. Our first chapter sets the scene with a discussion about the effects of forest management on ecosystem services. Details about forest observational infrastructures are introduced in the second chapter. The third chapter presents methods of analysing forest density and structure. Models for estimating the shape and growth of individual forest trees are introduced in chapter 4, models of forest community production in Chapter 5. Methods and examples of sustainable forest design are covered in chapter 6. New scientific contributions continue to emerge as we are writing, and this work is never finished. We hope to continue with regular updates replacing obsolete sections with new ones, but the general aim remains the same, to introduce a range of methods that will assist those interested in sustaining forest ecosystems.
Singular systems which are also referred to as descriptor systems, semi-state systems, differential- algebraic systems or generalized state-space systems have attracted much attention because of their extensive applications in the Leontief dynamic model, electrical and mechanical models, etc. This monograph presented up-to-date research developments and references on stability analysis and design of nonlinear singular systems. It investigated the problems of practical stability, strongly absolute stability, input-state stability and observer design for nonlinear singular systems and the problems of absolute stability and multi-objective control for nonlinear singularly perturbed systems by using Lyapunov stability theory, comparison principle, S-procedure and linear matrix inequality (LMI), etc. Practical stability, being quite different from stability in the sense of Lyapunov, is a significant performance specification from an engineering point of view. The basic concepts and results on practical stability for standard state-space systems were generalized to singular systems. For Lur’e type descriptor systems (LDS) which were the feedback interconnection of a descriptor system with a static nonlinearity, strongly absolute stability was defined and Circle criterion and Popov criterion were derived. The notion of input-state stability (ISS) for nonlinear singular systems was defined based on the concept of ISS for standard state-space systems and the characteristics of singular systems. LMI-based sufficient conditions for ISS of Lur’e singular systems were proposed. Furthermore, observer design for nonlinear singular systems was studied and some observer design methods were proposed by the obtained stability results and convex optimization algorithms. Finally, absolute stability and multi-objective control of nonlinear singularly perturbed systems were considered. By Lyapunov functions, absolute stability criteria of Lur’e singularly perturbed systems were proposed and multi-objective control of T-S fuzzy singularly perturbed systems was achieved. Compared with the existing results, the obtained methods do not depend on the decomposition of the original system and can produce a determinate upper bound for the singular perturbation parameter.
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