Wireless Mesh Networks is vulnerable to attacks due to the open medium, dynamically changing network topology, cooperative algorithms, Lack of centralized monitoring and management point. The traditional way of protec...Wireless Mesh Networks is vulnerable to attacks due to the open medium, dynamically changing network topology, cooperative algorithms, Lack of centralized monitoring and management point. The traditional way of protecting networks with firewalls and encryption software is no longer suffi- cient and effective for those features. In this paper, we propose a distributed intrusion detection ap- proach based on timed automata. A cluster-based detection scheme is presented, where periodically a node is elected as the monitor node for a cluster. These monitor nodes can not only make local intrusion detection decisions, but also cooperatively take part in global intrusion detection. And then we con- struct the Finite State Machine （FSM） by the way of manually abstracting the correct behaviors of the node according to the routing protocol of Dynamic Source Routing （DSR）. The monitor nodes can verify every node＇s behavior by the Finite State Ma- chine （FSM）, and validly detect real-time attacks without signatures of intrusion or trained data.Compared with the architecture where each node is its own IDS agent, our approach is much more efficient while maintaining the same level of effectiveness. Finally, we evaluate the intrusion detection method through simulation experiments.展开更多
Introduction of foreign plants and animals into Thailand＇s ecology has a long history, some arrived accidentally and others had a purpose. As global commerce increases, the issue of invasive alien species has become ...Introduction of foreign plants and animals into Thailand＇s ecology has a long history, some arrived accidentally and others had a purpose. As global commerce increases, the issue of invasive alien species has become more urgent in Thailand. These agents are increasingly seen as a threat not only to biodiversity and ecosystem, but also to economic development and human well-being. They reduce yields of agricultural crops, forests and fisheries, decrease water availability, cause costly land degradation, block transport routes and contribute to the spread of disease. It is clear that since trade will not stop, dangerous alien species need to be controlled and managed and the strategies and control measures are to prevent, eradicate, contain, or effectively control the invaders. Implementation of these measures requires appropriate legislation, regulation and procedures. The impact of some invasive alien pests and their management on the agricultural sector of Thailand are presented.展开更多
Plants that expand their range and become invasive in other areas may shift several functional traits in response to specific environments.However,local conditions at the place of origin may have shaped the functional...Plants that expand their range and become invasive in other areas may shift several functional traits in response to specific environments.However,local conditions at the place of origin may have shaped the functional traits,which may to some extent remain visible in plants growing in new habitats.The present study aimed to explore the trait variation in different plant populations of native,invasive and naturalized status of Bunias orientalis grown in common conditions in relation to the climatic conditions at their place of origin.Seeds of B.orientalis were collected from 12 populations(4 per status)in 8 countries and grown under standardized conditions in a common field garden.The variation in several functional traits related to phenology,growth and reproduction was compared among status and among populations.Phenology did not differ according to status.However,several plants of the native populations,originating from areas with low annual temperatures,did not start flowering.Plants of the invasive populations produced more leaves than natives,potentially indicating their vigor in building up vegetative biomass.Number and mass of silicles and other growth traits did not differ among status groups but varied among populations.Some of the variation in functional traits may be explained by long-term adaptations to local conditions at the areas of origin and genetic diversity,while other environmental factors differing in the novel environment may contribute to a high trait variation.展开更多
基金Acknowledgements Project supported by the National Natural Science Foundation of China （Grant No.60932003）, the National High Technology Development 863 Program of China （Grant No.2007AA01Z452, No. 2009AA01 Z118 ）, Project supported by Shanghai Municipal Natural Science Foundation （Grant No.09ZRI414900）, National Undergraduate Innovative Test Program （091024812）.
文摘Wireless Mesh Networks is vulnerable to attacks due to the open medium, dynamically changing network topology, cooperative algorithms, Lack of centralized monitoring and management point. The traditional way of protecting networks with firewalls and encryption software is no longer suffi- cient and effective for those features. In this paper, we propose a distributed intrusion detection ap- proach based on timed automata. A cluster-based detection scheme is presented, where periodically a node is elected as the monitor node for a cluster. These monitor nodes can not only make local intrusion detection decisions, but also cooperatively take part in global intrusion detection. And then we con- struct the Finite State Machine （FSM） by the way of manually abstracting the correct behaviors of the node according to the routing protocol of Dynamic Source Routing （DSR）. The monitor nodes can verify every node＇s behavior by the Finite State Ma- chine （FSM）, and validly detect real-time attacks without signatures of intrusion or trained data.Compared with the architecture where each node is its own IDS agent, our approach is much more efficient while maintaining the same level of effectiveness. Finally, we evaluate the intrusion detection method through simulation experiments.
文摘Introduction of foreign plants and animals into Thailand＇s ecology has a long history, some arrived accidentally and others had a purpose. As global commerce increases, the issue of invasive alien species has become more urgent in Thailand. These agents are increasingly seen as a threat not only to biodiversity and ecosystem, but also to economic development and human well-being. They reduce yields of agricultural crops, forests and fisheries, decrease water availability, cause costly land degradation, block transport routes and contribute to the spread of disease. It is clear that since trade will not stop, dangerous alien species need to be controlled and managed and the strategies and control measures are to prevent, eradicate, contain, or effectively control the invaders. Implementation of these measures requires appropriate legislation, regulation and procedures. The impact of some invasive alien pests and their management on the agricultural sector of Thailand are presented.
文摘Plants that expand their range and become invasive in other areas may shift several functional traits in response to specific environments.However,local conditions at the place of origin may have shaped the functional traits,which may to some extent remain visible in plants growing in new habitats.The present study aimed to explore the trait variation in different plant populations of native,invasive and naturalized status of Bunias orientalis grown in common conditions in relation to the climatic conditions at their place of origin.Seeds of B.orientalis were collected from 12 populations(4 per status)in 8 countries and grown under standardized conditions in a common field garden.The variation in several functional traits related to phenology,growth and reproduction was compared among status and among populations.Phenology did not differ according to status.However,several plants of the native populations,originating from areas with low annual temperatures,did not start flowering.Plants of the invasive populations produced more leaves than natives,potentially indicating their vigor in building up vegetative biomass.Number and mass of silicles and other growth traits did not differ among status groups but varied among populations.Some of the variation in functional traits may be explained by long-term adaptations to local conditions at the areas of origin and genetic diversity,while other environmental factors differing in the novel environment may contribute to a high trait variation.
