The conversion of forested areas to non-forest land was a series problem in study area of Goba district. The objectives of this study were to assess the trends, causes and effects of deforestation in Goba district, Ba...The conversion of forested areas to non-forest land was a series problem in study area of Goba district. The objectives of this study were to assess the trends, causes and effects of deforestation in Goba district, Bale zone, Ethiopia. Descriptive research method was employed to achieve these stated objectives. Satellite image of the three times and socio-economic survey were the main data sources for this study. ERDAS imagine 9.2 and ArcGIS 10 tools were applied for land use and land cover type classification, and analysis and mapping. These land use land and over change data were obtained from USGS. Socio-economic data collected through questionnaires, focus group discussions and interviews on the causes and impacts of land use and land cover change were analyzed quantitatively using SPSS software and content analysis for qualitative data. These analyzed data were expressed in percent and in words. The result shows that there was variation in the extent of land use and land cover change among different categories/classes at different study periods. Open area and Bush land showed decreasing change during first period of comparison and increasing change in the second period of comparison. In contrast, agricultural area, Bale temperate vegetation and built up area showed increasing. Built up area, agricultural area and Bale temperate vegetation increased by 80.05, 15.84, and 7.40 percent respectively, however, open area, grassland, forest land and bush land decreased by 1.58, 1.21, 0.97, and 0.28 percent per year for the last 29 years respectively. In general, in study district forest cover was 50.87% of the total area in 1986 and decreased to 36.57% in 2015 whereas agricultural area was increased from 3.45% to 19.28% respectively. This implies an increasing agricultural area at the expense of other land use cover categories, particularly natural forest. The study indicated that increasing population, forest fire and fuel wood consumption, overgrazing, and agriculture and settlement expansion and road construction caused forest cover change in the district. A decrease in livelihood incomes, volume of the surface water and in contrary increase in rain fall and temperature variability and forest product costs were among the major observed effects of deforestation in study area. Based on these findings, the study recommends the need to introduce and develop agricultural extension services, alternative energy sources and awareness raising services to the study area.展开更多
引入广义光突发汇聚(GOBA)概念对传统光突发交换(OBS)进行扩展,形成新的广义OBS(GOBS)网络。针对GOBS的多业务承载目标,提出了一种支持多业务承载的GOBA机制,采用将业务最小时延要求作为汇聚时间的汇聚方式,将多种用户数据业务汇聚到不...引入广义光突发汇聚(GOBA)概念对传统光突发交换(OBS)进行扩展,形成新的广义OBS(GOBS)网络。针对GOBS的多业务承载目标,提出了一种支持多业务承载的GOBA机制,采用将业务最小时延要求作为汇聚时间的汇聚方式,将多种用户数据业务汇聚到不同粒度的广义数据突发(GDB)中。仿真结果表明,在GOBS环境下,与MSMAP(max burst-size max assembly period)机制相比,GOBA能够在满足较高数据成功接收率的基础上显著地减小约10%的总体数据超时率,同时降低约15%的突发碰撞率,并提高约20%信道利用率。展开更多
文摘The conversion of forested areas to non-forest land was a series problem in study area of Goba district. The objectives of this study were to assess the trends, causes and effects of deforestation in Goba district, Bale zone, Ethiopia. Descriptive research method was employed to achieve these stated objectives. Satellite image of the three times and socio-economic survey were the main data sources for this study. ERDAS imagine 9.2 and ArcGIS 10 tools were applied for land use and land cover type classification, and analysis and mapping. These land use land and over change data were obtained from USGS. Socio-economic data collected through questionnaires, focus group discussions and interviews on the causes and impacts of land use and land cover change were analyzed quantitatively using SPSS software and content analysis for qualitative data. These analyzed data were expressed in percent and in words. The result shows that there was variation in the extent of land use and land cover change among different categories/classes at different study periods. Open area and Bush land showed decreasing change during first period of comparison and increasing change in the second period of comparison. In contrast, agricultural area, Bale temperate vegetation and built up area showed increasing. Built up area, agricultural area and Bale temperate vegetation increased by 80.05, 15.84, and 7.40 percent respectively, however, open area, grassland, forest land and bush land decreased by 1.58, 1.21, 0.97, and 0.28 percent per year for the last 29 years respectively. In general, in study district forest cover was 50.87% of the total area in 1986 and decreased to 36.57% in 2015 whereas agricultural area was increased from 3.45% to 19.28% respectively. This implies an increasing agricultural area at the expense of other land use cover categories, particularly natural forest. The study indicated that increasing population, forest fire and fuel wood consumption, overgrazing, and agriculture and settlement expansion and road construction caused forest cover change in the district. A decrease in livelihood incomes, volume of the surface water and in contrary increase in rain fall and temperature variability and forest product costs were among the major observed effects of deforestation in study area. Based on these findings, the study recommends the need to introduce and develop agricultural extension services, alternative energy sources and awareness raising services to the study area.
文摘引入广义光突发汇聚(GOBA)概念对传统光突发交换(OBS)进行扩展,形成新的广义OBS(GOBS)网络。针对GOBS的多业务承载目标,提出了一种支持多业务承载的GOBA机制,采用将业务最小时延要求作为汇聚时间的汇聚方式,将多种用户数据业务汇聚到不同粒度的广义数据突发(GDB)中。仿真结果表明,在GOBS环境下,与MSMAP(max burst-size max assembly period)机制相比,GOBA能够在满足较高数据成功接收率的基础上显著地减小约10%的总体数据超时率,同时降低约15%的突发碰撞率,并提高约20%信道利用率。
