为了解决移动机器人在复杂环境中物体抓取规划成功率低以及规划时间长等问题,本文提出了一种基于环境信息的预处理生成移动机器人停靠位置优化算法。首先对机械臂的工作空间进行分析,得到抓取难易评价标准,将环境中目标物、障碍物以及...为了解决移动机器人在复杂环境中物体抓取规划成功率低以及规划时间长等问题,本文提出了一种基于环境信息的预处理生成移动机器人停靠位置优化算法。首先对机械臂的工作空间进行分析,得到抓取难易评价标准,将环境中目标物、障碍物以及移动底盘位置简化为点,投影到xy平面上,根据抓取难易评价标准求出移动机器人优化后的底盘停靠位置;然后针对机械臂避障问题,采用快速扩展随机树(Rapidly-exploring Random Trees,RRT)算法实现了机械臂末端及连杆与障碍物的避障;最后通过仿真和动作捕捉系统下的实验发现,采用移动机器人停靠位置优化算法可显著提高抓取规划成功率和规划速度。展开更多
Based on catastrophe theory,we used the catastrophe progression method to predict the risk of coal and gas outbursts in coal mines.According to the major factors affecting coal and gas outbursts,we built a comprehensi...Based on catastrophe theory,we used the catastrophe progression method to predict the risk of coal and gas outbursts in coal mines.According to the major factors affecting coal and gas outbursts,we built a comprehensive evaluation index system and a coal and gas outburst prediction model.In addition,we performed a standard transformation for each index system;based on the degree the various indices affect the risk of an outburst,to make the data dimensionless.Based on the outburst data from eight mines,we determined catastrophe progression values and verified these values.The results show that:1) converting multi-dimensional problems into one-dimensional problems using this catastrophe progression method can simplify the steps of predicting coal and gas outbursts;2) when pre-determined catastrophe progression values are used to predict coal and gas outbursts,the predicting accuracy rate can be as high as 87.5%;3) the various coal mines have different factors inducing outbursts with varying importance of these factors and 4) the catastrophe progression values,calculated based on these factors,can be used effectively to predict the risk of outbursts in coal mines.展开更多
The present study is focused on a comparative evaluation of landslide disaster using analytical hierarchy process and information value method for hazard assessment in highly tectonic Chamba region in bosom of Himalay...The present study is focused on a comparative evaluation of landslide disaster using analytical hierarchy process and information value method for hazard assessment in highly tectonic Chamba region in bosom of Himalaya. During study, the information about the causative factors was generated and the landslide hazard zonation maps were delineated using Information Value Method(IV) and Analytical Hierarchy Process(AHP) using Arc GIS(ESRI). For this purpose, the study area was selected in a part of Ravi river catchment along one of the landslide prone Chamba to Bharmour road corridor of National Highway(NH^(-1)54 A) in Himachal Pradesh, India. A numeral landslide triggering geoenvironmental factors i.e. slope, aspect, relative relief, soil, curvature, land use and land cover(LULC), lithology, drainage density, and lineament density were selected for landslide hazard mapping based on landslide inventory. Landslide hazard zonation map was categorized namely "very high hazard, high hazard, medium hazard, low hazard, and very low hazard". The results from these two methods were validated using Area Under Curve(AUC) plots. It is found that hazard zonation map prepared using information value method and analytical hierarchy process methods possess the prediction rate of 78.87% and 75.42%, respectively. Hence, landslide hazardzonation map obtained using information value method is proposed to be more useful for the study area. These final hazard zonation maps can be used by various stakeholders like engineers and administrators for proper maintenance and smooth traffic flow between Chamba and Bharmour cities, which is the only route connecting these tourist places.展开更多
Extreme weather and climate events are likely to cause disastrous consequences for agriculture and food security. This study investigated the impacts of drought in year 2012 on corn yield in the United States Corn Bel...Extreme weather and climate events are likely to cause disastrous consequences for agriculture and food security. This study investigated the impacts of drought in year 2012 on corn yield in the United States Corn Belt by integrating county-level crop yield data from the USDA NASS Quick Stats database and precipitation data from the NCDC GHCN-Daily database. It is found that precipitation over an 8-week period in corn growth stages is critical for corn yield, the logarithm of precipitation during the period explained 55% of corn yield variation. The results indicated the importance of water supply in corn silking stage, and provided an approach to assess the impacts of drought on corn yield quantitatively.展开更多
Cities are centers of socioeconomic activities,and transport networks carry cargoes and passengers from one city to another. However, transport networks are influenced by meteorological hazards, such as rainstorms,hur...Cities are centers of socioeconomic activities,and transport networks carry cargoes and passengers from one city to another. However, transport networks are influenced by meteorological hazards, such as rainstorms,hurricanes, and fog. Adverse weather impacts can easily spread over a network. Existing models evaluating such impacts usually neglect the transdisciplinary nature of approaches for dealing with this problem. In this article, a mesoscopic mathematical model is proposed to quantitatively assess the adverse impact of rainstorms on a regional transport network in northern China by measuring the reduction in traffic volume. The model considers four factors: direct and secondary impacts of rainstorms, interdependency between network components, and recovery abilities of cities. We selected the Beijing-Tianjin-Hebei region as the case study area to verify our model.Socioeconomic, precipitation, and traffic volume data in this area were used for model calibration and validation.The case study highlights the potential of the proposed model for rapid disaster loss assessment and risk reduction planning.展开更多
French insurance is part of a public-private partnership with the French State to compensate flood-related damages, and there is growing concern among insurers about damaging climatic events. To promote preventive act...French insurance is part of a public-private partnership with the French State to compensate flood-related damages, and there is growing concern among insurers about damaging climatic events. To promote preventive actions as well as to take them into account in flood risk assessment, insurers have recently expressed the need to develop a rating system of preventive actions. This study identified Action Programs for Flood Prevention (Programme d’Action pour la Prévention des Inondations—PAPI) as the key French public policy instrument: they provide an overview of the diversity of actions that are conducted locally at the relevant risk basin scale. A database of all intended actions in the 145 launched PAPIs was constructed and the actions were coded (88 codes). The analysis consisted of two steps: (1) We conducted an expert valuation using the Analytic Network Process and the Analytic Hierarchy Process, aiming at creating an experimental national rating system. The results show the importance of implementing an integrated strategy that particularly emphasizes land use planning and urban planning. This appears even sounder as individual actions show relatively limited effectiveness. (2) The ratings of actions were applied to each PAPI according to their implemented actions. The resulting scores for individual PAPIs, as local risk coping capacity indicators, show great variance ranging from 8 to 324 points. This confirms the need to take prevention into account in flood risk assessment.展开更多
Disaster risk depends on both the physical vulnerability and a wide range of social, economic, and environmental aspects of a society. For a better risk understanding, a holistic or integrated perspective was consider...Disaster risk depends on both the physical vulnerability and a wide range of social, economic, and environmental aspects of a society. For a better risk understanding, a holistic or integrated perspective was considered when risk was assessed for the city of Manizales, Colombia. This assessment accounts not only for the expected physical damage and loss, but also for the socioeconomic vulnerability factors that favor secondorder effects in a disaster. This comprehensive approach allows the identification of different aspects related to physical vulnerability, social fragility, and lack of resilience that can be improved, thus enhancing integrated disaster risk management actions. The outcomes of this comprehensive assessment are currently being used as input to update the disaster risk management plan of Manizales.展开更多
文摘为了解决移动机器人在复杂环境中物体抓取规划成功率低以及规划时间长等问题,本文提出了一种基于环境信息的预处理生成移动机器人停靠位置优化算法。首先对机械臂的工作空间进行分析,得到抓取难易评价标准,将环境中目标物、障碍物以及移动底盘位置简化为点,投影到xy平面上,根据抓取难易评价标准求出移动机器人优化后的底盘停靠位置;然后针对机械臂避障问题,采用快速扩展随机树(Rapidly-exploring Random Trees,RRT)算法实现了机械臂末端及连杆与障碍物的避障;最后通过仿真和动作捕捉系统下的实验发现,采用移动机器人停靠位置优化算法可显著提高抓取规划成功率和规划速度。
基金Projects 50574072, 50874089 and 50534049 supported by the National Natural Science Foundation of China08JK366 by the Special Scientific Foundation of Educational Committee of Shaanxi Province
文摘Based on catastrophe theory,we used the catastrophe progression method to predict the risk of coal and gas outbursts in coal mines.According to the major factors affecting coal and gas outbursts,we built a comprehensive evaluation index system and a coal and gas outburst prediction model.In addition,we performed a standard transformation for each index system;based on the degree the various indices affect the risk of an outburst,to make the data dimensionless.Based on the outburst data from eight mines,we determined catastrophe progression values and verified these values.The results show that:1) converting multi-dimensional problems into one-dimensional problems using this catastrophe progression method can simplify the steps of predicting coal and gas outbursts;2) when pre-determined catastrophe progression values are used to predict coal and gas outbursts,the predicting accuracy rate can be as high as 87.5%;3) the various coal mines have different factors inducing outbursts with varying importance of these factors and 4) the catastrophe progression values,calculated based on these factors,can be used effectively to predict the risk of outbursts in coal mines.
文摘The present study is focused on a comparative evaluation of landslide disaster using analytical hierarchy process and information value method for hazard assessment in highly tectonic Chamba region in bosom of Himalaya. During study, the information about the causative factors was generated and the landslide hazard zonation maps were delineated using Information Value Method(IV) and Analytical Hierarchy Process(AHP) using Arc GIS(ESRI). For this purpose, the study area was selected in a part of Ravi river catchment along one of the landslide prone Chamba to Bharmour road corridor of National Highway(NH^(-1)54 A) in Himachal Pradesh, India. A numeral landslide triggering geoenvironmental factors i.e. slope, aspect, relative relief, soil, curvature, land use and land cover(LULC), lithology, drainage density, and lineament density were selected for landslide hazard mapping based on landslide inventory. Landslide hazard zonation map was categorized namely "very high hazard, high hazard, medium hazard, low hazard, and very low hazard". The results from these two methods were validated using Area Under Curve(AUC) plots. It is found that hazard zonation map prepared using information value method and analytical hierarchy process methods possess the prediction rate of 78.87% and 75.42%, respectively. Hence, landslide hazardzonation map obtained using information value method is proposed to be more useful for the study area. These final hazard zonation maps can be used by various stakeholders like engineers and administrators for proper maintenance and smooth traffic flow between Chamba and Bharmour cities, which is the only route connecting these tourist places.
文摘Extreme weather and climate events are likely to cause disastrous consequences for agriculture and food security. This study investigated the impacts of drought in year 2012 on corn yield in the United States Corn Belt by integrating county-level crop yield data from the USDA NASS Quick Stats database and precipitation data from the NCDC GHCN-Daily database. It is found that precipitation over an 8-week period in corn growth stages is critical for corn yield, the logarithm of precipitation during the period explained 55% of corn yield variation. The results indicated the importance of water supply in corn silking stage, and provided an approach to assess the impacts of drought on corn yield quantitatively.
基金sponsored by the National Science Foundation of China Youth Project (#41401599)the National Basic Research Program of China (2012CB955402)+2 种基金the Beijing Municipal Science and Technology Commission (Z151100002115040)the International Cooperation Project (2012DFG20710)the International Center of Collaborative Research on Disaster Risk Reduction
文摘Cities are centers of socioeconomic activities,and transport networks carry cargoes and passengers from one city to another. However, transport networks are influenced by meteorological hazards, such as rainstorms,hurricanes, and fog. Adverse weather impacts can easily spread over a network. Existing models evaluating such impacts usually neglect the transdisciplinary nature of approaches for dealing with this problem. In this article, a mesoscopic mathematical model is proposed to quantitatively assess the adverse impact of rainstorms on a regional transport network in northern China by measuring the reduction in traffic volume. The model considers four factors: direct and secondary impacts of rainstorms, interdependency between network components, and recovery abilities of cities. We selected the Beijing-Tianjin-Hebei region as the case study area to verify our model.Socioeconomic, precipitation, and traffic volume data in this area were used for model calibration and validation.The case study highlights the potential of the proposed model for rapid disaster loss assessment and risk reduction planning.
文摘French insurance is part of a public-private partnership with the French State to compensate flood-related damages, and there is growing concern among insurers about damaging climatic events. To promote preventive actions as well as to take them into account in flood risk assessment, insurers have recently expressed the need to develop a rating system of preventive actions. This study identified Action Programs for Flood Prevention (Programme d’Action pour la Prévention des Inondations—PAPI) as the key French public policy instrument: they provide an overview of the diversity of actions that are conducted locally at the relevant risk basin scale. A database of all intended actions in the 145 launched PAPIs was constructed and the actions were coded (88 codes). The analysis consisted of two steps: (1) We conducted an expert valuation using the Analytic Network Process and the Analytic Hierarchy Process, aiming at creating an experimental national rating system. The results show the importance of implementing an integrated strategy that particularly emphasizes land use planning and urban planning. This appears even sounder as individual actions show relatively limited effectiveness. (2) The ratings of actions were applied to each PAPI according to their implemented actions. The resulting scores for individual PAPIs, as local risk coping capacity indicators, show great variance ranging from 8 to 324 points. This confirms the need to take prevention into account in flood risk assessment.
基金the support of the Ministry of Education and Science of Spain ‘‘Evaluación de la Vulnerabilidad y el Riesgo de Zonas Urbanas Expuestas a Amenazas Naturales y Antrópicas-EZUANA’’ (BIA2016-78544-R)
文摘Disaster risk depends on both the physical vulnerability and a wide range of social, economic, and environmental aspects of a society. For a better risk understanding, a holistic or integrated perspective was considered when risk was assessed for the city of Manizales, Colombia. This assessment accounts not only for the expected physical damage and loss, but also for the socioeconomic vulnerability factors that favor secondorder effects in a disaster. This comprehensive approach allows the identification of different aspects related to physical vulnerability, social fragility, and lack of resilience that can be improved, thus enhancing integrated disaster risk management actions. The outcomes of this comprehensive assessment are currently being used as input to update the disaster risk management plan of Manizales.
