Climate events pose major challenges to food production and the livelihoods of rural inhabitants in northern Laos, where upland rice using swidden production is an important crop. The onset of the rainy season in this...Climate events pose major challenges to food production and the livelihoods of rural inhabitants in northern Laos, where upland rice using swidden production is an important crop. The onset of the rainy season in this area is one such climate event, and it has occurred earlier and with less regularity in recent years. Not all households are able to cope with these changes. This study examines the ability of local farmers to cope with rice insufficiency. This investigation also clarifies household strategies in dealing with the climate event. We randomly interviewed 63 of 95 household heads, and performed a paired sample t test to examine the significance of differences in three household groups between the 2010 normal climate and the 2011 climate event. The groups were categorized according to rice selfsufficiency in 2011: groups I are households with rice self-sufficiency, group II are those facing a rice shortage of up to 3 months, and group III are those with insufficient rice for over 3 months. We also conducted a one-way ANOVA to examine the significance of differences in livelihood strategies among the three groups. We found that the household labor force was the most important factor in enhancing the villagers' ability to deal with the climate event and that the level of impact of that event shaped their coping strategies. Households with substantial labor force had more options for coping strategies than those with smaller ones. The villagers faced different levels of impact and adopted differentcoping strategies accordingly. Non-timber forest product collection was the principle livelihood strategy in response to non-climate factors such as education, access to health services, provision of equipment and clothing, and overcoming the impact of the climate event. Households heavily affected by the early rainy season onset tended to engage in intensive activities such as off-farm activity and outside work, rather than their major livelihood activities in the village(upland crop and livestock production).展开更多
Coexistence of satellite and terrestrial wireless communication systems in the same frequency band is quite promising for addressing the challenge of spectrum scarcity. To cope with the inevitable inter-system interfe...Coexistence of satellite and terrestrial wireless communication systems in the same frequency band is quite promising for addressing the challenge of spectrum scarcity. To cope with the inevitable inter-system interference, radio resource allocation at both sides should be carefully re-optimized. In this paper, we focus on a scenario where a satellite communication system and a terrestrial distributed antenna system(DAS) coexist via spectrum sharing. We particularly utilize the radio map(RM) to reduce the system overhead for channel acquisition. Based on the large-scale channel state information at the transmitter(CSIT), which is derived from the RM, we propose an optimized power allocation scheme to improve the achievable sum rate of the terrestrial system. For the satellite side, an opportunistic user scheduling scheme is presented, to reduce the harmful leakage interference to the terrestrial mobile users. Simulation results demonstrate that the proposed RM-based coordination scheme can significantly promote the performance of satellite terrestrial coexistence, although the small-scale channel fading has been ignored in the formulated optimization.展开更多
Based on GPS data from 1991- 2004 and the least-squares collocation method,we analyze the crustal deformation in the Chinese mainland. The results show that the first-order crustal deformation is unchanged in differen...Based on GPS data from 1991- 2004 and the least-squares collocation method,we analyze the crustal deformation in the Chinese mainland. The results show that the first-order crustal deformation is unchanged in different periods in the Chinese mainland,which reflects the background of regional tectonic activity. The strain rate is much higher in Western China,especially in the Qinghai-Tibetan Plateau and Sichuan-Yunnan area. The variations in different periods are related with seismicity of strong earthquakes during the same time. The GPS data after 2004 shows the post-seismic deformation of the 2001 Kunlun Mountains M S8. 1 earthquake.展开更多
The optimization of land-use spatio-structure is one of the most important areas of land use management;constructing a spatial optimization model that is based on the micro spatial unit in a bottom-up mode plays an im...The optimization of land-use spatio-structure is one of the most important areas of land use management;constructing a spatial optimization model that is based on the micro spatial unit in a bottom-up mode plays an important role in coupling the quan-tity structure and spatial structure effectively.The objective of this research is to develop a land use spatial optimization model based on particle swarm optimization to make spatial decision in land use management.The model is implemented using real data-sets to emulate the process of spatial structure optimization in order to get the best landscape pattern under the control of decision environments.Simulation results revealed that the particle swarm optimization model has the ability to utilize the quantity and spa-tial structure.Furthermore,the result demonstrated that it can be used to stimulate the landscape pattern in designing the appropriate optimization environment,which could land quantity target to the basic spatial units effectively and provide appropriate spa-tio-structure for regional land use space layout decision making.展开更多
基金funded by Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research (Kakenhi), Scientific Research (A)
文摘Climate events pose major challenges to food production and the livelihoods of rural inhabitants in northern Laos, where upland rice using swidden production is an important crop. The onset of the rainy season in this area is one such climate event, and it has occurred earlier and with less regularity in recent years. Not all households are able to cope with these changes. This study examines the ability of local farmers to cope with rice insufficiency. This investigation also clarifies household strategies in dealing with the climate event. We randomly interviewed 63 of 95 household heads, and performed a paired sample t test to examine the significance of differences in three household groups between the 2010 normal climate and the 2011 climate event. The groups were categorized according to rice selfsufficiency in 2011: groups I are households with rice self-sufficiency, group II are those facing a rice shortage of up to 3 months, and group III are those with insufficient rice for over 3 months. We also conducted a one-way ANOVA to examine the significance of differences in livelihood strategies among the three groups. We found that the household labor force was the most important factor in enhancing the villagers' ability to deal with the climate event and that the level of impact of that event shaped their coping strategies. Households with substantial labor force had more options for coping strategies than those with smaller ones. The villagers faced different levels of impact and adopted differentcoping strategies accordingly. Non-timber forest product collection was the principle livelihood strategy in response to non-climate factors such as education, access to health services, provision of equipment and clothing, and overcoming the impact of the climate event. Households heavily affected by the early rainy season onset tended to engage in intensive activities such as off-farm activity and outside work, rather than their major livelihood activities in the village(upland crop and livestock production).
基金supported in part by the National Science Foundation of China under grant No.61701457
文摘Coexistence of satellite and terrestrial wireless communication systems in the same frequency band is quite promising for addressing the challenge of spectrum scarcity. To cope with the inevitable inter-system interference, radio resource allocation at both sides should be carefully re-optimized. In this paper, we focus on a scenario where a satellite communication system and a terrestrial distributed antenna system(DAS) coexist via spectrum sharing. We particularly utilize the radio map(RM) to reduce the system overhead for channel acquisition. Based on the large-scale channel state information at the transmitter(CSIT), which is derived from the RM, we propose an optimized power allocation scheme to improve the achievable sum rate of the terrestrial system. For the satellite side, an opportunistic user scheduling scheme is presented, to reduce the harmful leakage interference to the terrestrial mobile users. Simulation results demonstrate that the proposed RM-based coordination scheme can significantly promote the performance of satellite terrestrial coexistence, although the small-scale channel fading has been ignored in the formulated optimization.
基金funded by the Science and Technology Support Program(2012BAK19B01)Natural Science Foundation of China(41104057,41104058)the special project of basic scientific research of Institute of Earthquake Science,China Earthquake Administration(2012IES0405,2012IES0406)
文摘Based on GPS data from 1991- 2004 and the least-squares collocation method,we analyze the crustal deformation in the Chinese mainland. The results show that the first-order crustal deformation is unchanged in different periods in the Chinese mainland,which reflects the background of regional tectonic activity. The strain rate is much higher in Western China,especially in the Qinghai-Tibetan Plateau and Sichuan-Yunnan area. The variations in different periods are related with seismicity of strong earthquakes during the same time. The GPS data after 2004 shows the post-seismic deformation of the 2001 Kunlun Mountains M S8. 1 earthquake.
基金Supported by the National Natural Science Foundation of China (No. 40701145, 40701143) the Open Foundation of State Key Laboratory of Information Engineering in Surveying,Mapping and Remote Sensing in Wuhan University, China(2009)
文摘The optimization of land-use spatio-structure is one of the most important areas of land use management;constructing a spatial optimization model that is based on the micro spatial unit in a bottom-up mode plays an important role in coupling the quan-tity structure and spatial structure effectively.The objective of this research is to develop a land use spatial optimization model based on particle swarm optimization to make spatial decision in land use management.The model is implemented using real data-sets to emulate the process of spatial structure optimization in order to get the best landscape pattern under the control of decision environments.Simulation results revealed that the particle swarm optimization model has the ability to utilize the quantity and spa-tial structure.Furthermore,the result demonstrated that it can be used to stimulate the landscape pattern in designing the appropriate optimization environment,which could land quantity target to the basic spatial units effectively and provide appropriate spa-tio-structure for regional land use space layout decision making.
