With the development of science, economy and society, the needs for research and exploration of deep space have entered a rapid and stable development stage. Deep Space Optical Network(DSON) is expected to become an i...With the development of science, economy and society, the needs for research and exploration of deep space have entered a rapid and stable development stage. Deep Space Optical Network(DSON) is expected to become an important foundation and inevitable development trend of future deepspace communication. In this paper, we design a deep space node model which is capable of combining the space division multiplexing with frequency division multiplexing. Furthermore, we propose the directional flooding routing algorithm(DFRA) for DSON based on our node model. This scheme selectively forwards the data packets in the routing, so that the energy consumption can be reduced effectively because only a portion of nodes will participate the flooding routing. Simulation results show that, compared with traditional flooding routing algorithm(TFRA), the DFRA can avoid the non-directional and blind transmission. Therefore, the energy consumption in message routing will be reduced and the lifespan of DSON can also be prolonged effectively. Although the complexity of routing implementation is slightly increased compared with TFRA, the energy of nodes can be saved and the transmission rate is obviously improved in DFRA. Thus the overall performance of DSON can be significantly improved.展开更多
How can the concrete meaning of the ambiguous and theoretical concept of sustainable development(SD) be defined and implemented, without losing sight of its fundamental principles? This study introduces a theoretical ...How can the concrete meaning of the ambiguous and theoretical concept of sustainable development(SD) be defined and implemented, without losing sight of its fundamental principles? This study introduces a theoretical framework that supports studies of SD implementation in the context of strategic disaster risk management, by defining what SD implies with regard to planning procedures. The framework is based on the procedural SD principles of participation and integration. It was originally developed for,and has shown great value in, the field of water resource management. In-depth interviews with senior risk management researchers indicate that the framework is also applicable to and valuable for disaster risk management studies.To illustrate the application of the framework, a study of the EU Floods Directive in Sweden is summarized with the framework as the basis for the analysis.展开更多
基金supported by National Natural Science Foundation of China (61471109, 61501104 and 91438110)Fundamental Research Funds for the Central Universities ( N140405005 , N150401002 and N150404002)Open Fund of IPOC (BUPT, IPOC2015B006)
文摘With the development of science, economy and society, the needs for research and exploration of deep space have entered a rapid and stable development stage. Deep Space Optical Network(DSON) is expected to become an important foundation and inevitable development trend of future deepspace communication. In this paper, we design a deep space node model which is capable of combining the space division multiplexing with frequency division multiplexing. Furthermore, we propose the directional flooding routing algorithm(DFRA) for DSON based on our node model. This scheme selectively forwards the data packets in the routing, so that the energy consumption can be reduced effectively because only a portion of nodes will participate the flooding routing. Simulation results show that, compared with traditional flooding routing algorithm(TFRA), the DFRA can avoid the non-directional and blind transmission. Therefore, the energy consumption in message routing will be reduced and the lifespan of DSON can also be prolonged effectively. Although the complexity of routing implementation is slightly increased compared with TFRA, the energy of nodes can be saved and the transmission rate is obviously improved in DFRA. Thus the overall performance of DSON can be significantly improved.
文摘How can the concrete meaning of the ambiguous and theoretical concept of sustainable development(SD) be defined and implemented, without losing sight of its fundamental principles? This study introduces a theoretical framework that supports studies of SD implementation in the context of strategic disaster risk management, by defining what SD implies with regard to planning procedures. The framework is based on the procedural SD principles of participation and integration. It was originally developed for,and has shown great value in, the field of water resource management. In-depth interviews with senior risk management researchers indicate that the framework is also applicable to and valuable for disaster risk management studies.To illustrate the application of the framework, a study of the EU Floods Directive in Sweden is summarized with the framework as the basis for the analysis.
