Flood is a recurrent natural disaster that has caused enormous human and material damage in many places and continues to hit local committees at an alarming rate. The need to setup permanent committees to prevent and ...Flood is a recurrent natural disaster that has caused enormous human and material damage in many places and continues to hit local committees at an alarming rate. The need to setup permanent committees to prevent and manage flood disasters by local communities is therefore indispensable. In rural areas, the creation of such a structure is always a welcome relief to flood victims but it is often marred by numerous management problems. This study aimed to analyze the community-based approach in the prevention and management of flood disasters in Babessi Subdivision (North West Cameroon), to identify the causes of flood disasters and the preventive strategies used by this local community. A total number of 300 questionnaires as well as structured interviews were used to collect data in the field and the data were analyzed by simple descriptive statistics. The main results revealed that the main cause of flood disasters is heavy and consistent rainfall. Also, poor refuse disposal and drainage system management contribute to floods. The identification of areas likely to be affected by floods and preventing the riparian population from constructing houses along these areas especially beside the main rivers are the flood preventive measures adopted by the local flood management committee. The flood victims are reluctant to relocate to the settlement site earmarked by the Government, meanwhile, the local flood committee do not have the legal tools to forcefully relocate them. The population of Babessi needs to be sensitized on the impending dangers of flood hazard and be encouraged to participate in implementing the adopted strategies to prevent and manage subsequent flood disasters.展开更多
中国区域定位系统(Chinese Area Positioning System,CAPS)是基于通信卫星的转发式卫星导航系统,基本原理是导航信号由地面导航站上行,经通信卫星转发向地面广播,用户接收机接收导航信号和电文实现导航定位。在试验验证阶段,CAPS仅采用...中国区域定位系统(Chinese Area Positioning System,CAPS)是基于通信卫星的转发式卫星导航系统,基本原理是导航信号由地面导航站上行,经通信卫星转发向地面广播,用户接收机接收导航信号和电文实现导航定位。在试验验证阶段,CAPS仅采用同步轨道通信卫星进行信号的转发和广播,用户接收机利用气压测高技术实现高程辅助下的定位解算。为了描述CAPS水平定位误差的分布,作者定义了高程辅助算法下的东精度衰减因子(Dilutionof Precision East,EDOP)和北精度衰减因子(Dilution of Precision North,NDOP)。根据CAPS星座分布,分析系统覆盖范围内高程辅助下EDOP和NDOP数值,结果表明CAPS的EDOP和NDOP是关于赤道南北对称,关于同步轨道通信卫星的平均经度子午圈对称。在平均经度子午圈附近,EDOP出现最小值;在同一纬度圈上,离平均子午圈越远,EDOP数值越大。在CAPS覆盖区域内,任一格点上的NDOP总是大于EDOP,当用户由低纬度地区向高纬度地区移动时,在站心坐标系内卫星在南北方向拉开的距离增大,NDOP变小。利用北京、上海、长春、西安、乌鲁木齐和昆明6个CAPS测站进行仿真分析,结果表明本文提出的EDOP和NDOP可用于估算星座空间布局对用户伪距测量误差的放大程度,并可以解释CAPS接收机在高程辅助下水平定位精度东西方向总是优于南北方向的现象。进一步的实测数据分析表明,EDOP和NDOP可以用来估算南北方向和东西方向的定位精度。展开更多
文摘Flood is a recurrent natural disaster that has caused enormous human and material damage in many places and continues to hit local committees at an alarming rate. The need to setup permanent committees to prevent and manage flood disasters by local communities is therefore indispensable. In rural areas, the creation of such a structure is always a welcome relief to flood victims but it is often marred by numerous management problems. This study aimed to analyze the community-based approach in the prevention and management of flood disasters in Babessi Subdivision (North West Cameroon), to identify the causes of flood disasters and the preventive strategies used by this local community. A total number of 300 questionnaires as well as structured interviews were used to collect data in the field and the data were analyzed by simple descriptive statistics. The main results revealed that the main cause of flood disasters is heavy and consistent rainfall. Also, poor refuse disposal and drainage system management contribute to floods. The identification of areas likely to be affected by floods and preventing the riparian population from constructing houses along these areas especially beside the main rivers are the flood preventive measures adopted by the local flood management committee. The flood victims are reluctant to relocate to the settlement site earmarked by the Government, meanwhile, the local flood committee do not have the legal tools to forcefully relocate them. The population of Babessi needs to be sensitized on the impending dangers of flood hazard and be encouraged to participate in implementing the adopted strategies to prevent and manage subsequent flood disasters.
文摘中国区域定位系统(Chinese Area Positioning System,CAPS)是基于通信卫星的转发式卫星导航系统,基本原理是导航信号由地面导航站上行,经通信卫星转发向地面广播,用户接收机接收导航信号和电文实现导航定位。在试验验证阶段,CAPS仅采用同步轨道通信卫星进行信号的转发和广播,用户接收机利用气压测高技术实现高程辅助下的定位解算。为了描述CAPS水平定位误差的分布,作者定义了高程辅助算法下的东精度衰减因子(Dilutionof Precision East,EDOP)和北精度衰减因子(Dilution of Precision North,NDOP)。根据CAPS星座分布,分析系统覆盖范围内高程辅助下EDOP和NDOP数值,结果表明CAPS的EDOP和NDOP是关于赤道南北对称,关于同步轨道通信卫星的平均经度子午圈对称。在平均经度子午圈附近,EDOP出现最小值;在同一纬度圈上,离平均子午圈越远,EDOP数值越大。在CAPS覆盖区域内,任一格点上的NDOP总是大于EDOP,当用户由低纬度地区向高纬度地区移动时,在站心坐标系内卫星在南北方向拉开的距离增大,NDOP变小。利用北京、上海、长春、西安、乌鲁木齐和昆明6个CAPS测站进行仿真分析,结果表明本文提出的EDOP和NDOP可用于估算星座空间布局对用户伪距测量误差的放大程度,并可以解释CAPS接收机在高程辅助下水平定位精度东西方向总是优于南北方向的现象。进一步的实测数据分析表明,EDOP和NDOP可以用来估算南北方向和东西方向的定位精度。
