Overlay networks have emerged as a useful approach to providing a general framework for new applications and services that are to be implemented without significantly changing the IP-layer network infrastructure.Overl...Overlay networks have emerged as a useful approach to providing a general framework for new applications and services that are to be implemented without significantly changing the IP-layer network infrastructure.Overlay routing has been used as an alternative to the default best effort Internet routing for the absence of end-to-end Quality of Service(QoS). While the former has recently been investigated, the conflict of QoS restraints and resource optimization remains unsolved. Recent studies have shown that overlay paths can give better latency, loss rate and TCP throughput. In this paper, a multi-dimensional QoS objective model based on the analysis of multiple QoS constraints has been presented, and a routing algorithm to optimise the overlay resource of its nodes and links is then proposed.In fact, the algorithm obtained multiple QoS values using probability theory to achieve the routing according to the multi-dimensional QoS objective vector of the QoS objective model. Simulation results reveals that the algorithm works better than other existing algorithms in balancing the network resources, and applications with stringent QoS requirements could be run.展开更多
The WHO World Health Assembly, and the most recent WHO World Health Report, have called for all health systems to move toward universal coverage. However, low-income countries have made little progress in this respect...The WHO World Health Assembly, and the most recent WHO World Health Report, have called for all health systems to move toward universal coverage. However, low-income countries have made little progress in this respect. We use existing evidence to describe the evolution of community-based health insurance in low-income countries through the three stages of basic model, enhanced model, and nationwide model. We have concluded that community-based health insurance development is a potential strategy to meet the urgent need for health financing in low-income countries. With careful planning and implementation, it is possible to adopt such evolutionary approach to achieve universal coverage by extending tax-based financing/social insurance characteristics to community-based health insurance schemes.展开更多
With trends indicating increase in temperature and decrease in winter precipitation, a significant negative trend in snow-covered areas has been identified in the last decade in the Himalayas. This requires a quantita...With trends indicating increase in temperature and decrease in winter precipitation, a significant negative trend in snow-covered areas has been identified in the last decade in the Himalayas. This requires a quantitative analysis of the snow cover in the higher Himalayas. In this study, a nonlinear autoregressive exogenous model, an artificial neural network （ANN）, was deployed to predict the snow cover in the Kaligandaki river basin for the next 30 years. Observed climatic data, and snow covered area was used to train and test the model that captures the gross features of snow under the current climate scenario. The range of the likely effects of climate change on seasonal snow was assessed in the Himalayas using downscaled temperature and precipitation change projection from - HadCM3, a global circulation model to project future climate scenario, under the AIB emission scenario, which describes a future world of very rapid economic growth with balance use between fossil and non-fossil energy sources. The results show that there is a reduction of 9% to 46% of snow cover in different elevation zones during the considered time period, i.e., 2Oll to 2040. The 4700 m to 52oo m elevation zone is the most affected area and the area higher than 5200 m is the least affected. Overall, however, it is clear from the analysis that seasonal snow in the Kaligandaki basin is likely to be subject to substantialchanges due to the impact of climate change.展开更多
In order to evaluate the danger of debris flow properly, eight factors were selected as the risk assess- ment indexes of the debris flow, namely the vertical slope, valley relative difference, hillside slope, area of ...In order to evaluate the danger of debris flow properly, eight factors were selected as the risk assess- ment indexes of the debris flow, namely the vertical slope, valley relative difference, hillside slope, area of ba- sin, loose solid material reserves, the path length of sediment supply probability, silting and scouring derrieking and vegetation coverage. The improved Analytic Hierarchy Process （ AHP ） method was used to obtain the weights of the factors; and the efficacy coefficient method was adopted to evaluate the risks of six typical debris flow gullies. According to the research, the improved AHP method not only avoids the subjectivity in the indi- vidual factor valuation by comparing two factors of each layer, but also makes the subsequent consistency check unnecessary.展开更多
We developed a method for analyzing the change in snow cover using MODIS imagery.The method was applied to images of western Sichuan Province,China taken between 2002 and 2008.The model for extracting data on snow cov...We developed a method for analyzing the change in snow cover using MODIS imagery.The method was applied to images of western Sichuan Province,China taken between 2002 and 2008.The model for extracting data on snow cover from MODIS images was created by spectral analysis.The multi-temporal snow layers were used to evaluate the temporal and spatial change in the area under snow cover between 2002 and 2008 using overlay and statistical analysis in ARCGIS.The majority(60.4%) of western Sichuan was rarely covered by snow and only 0.3% was covered by perennial snow in 2002.Snow cover was pri-marily distributed in Garzê and Aba.The area under snow cover was significantly and negatively correlated with the average monthly temperature and rainfall in 2002.The largest area under snow cover was measured in 2006 and the smallest was in 2007.Similarly,the area of snowmelt was the highest in 2006 and lowest in 2007.In general,the elevation of the snow line in-creased throughout the period 2002-2008;however,the elevation decreased in some years.Our results provide an important insight into the distribution of snow in this region,and may be useful for climate modeling and predicting the availability of water resources and the occurrence of floods and droughts.展开更多
The author constructs the sheaf of generalized fundamental group of a topological space Xand obtains the relationship between its lst cohomology set and all covering spaces Of X undersuitable conditions imposed upon X.
基金supported by the National Natural Science Foundation of China under Grant No.61071126the National Science and Technology Major Projects of New Generation Broadband Wireless Mobile Communication Network under Grants No.2010ZX0300400201,No.2010ZX03003-001,No.2010ZX03004-001-01,No.2011ZX03002-001-02
文摘Overlay networks have emerged as a useful approach to providing a general framework for new applications and services that are to be implemented without significantly changing the IP-layer network infrastructure.Overlay routing has been used as an alternative to the default best effort Internet routing for the absence of end-to-end Quality of Service(QoS). While the former has recently been investigated, the conflict of QoS restraints and resource optimization remains unsolved. Recent studies have shown that overlay paths can give better latency, loss rate and TCP throughput. In this paper, a multi-dimensional QoS objective model based on the analysis of multiple QoS constraints has been presented, and a routing algorithm to optimise the overlay resource of its nodes and links is then proposed.In fact, the algorithm obtained multiple QoS values using probability theory to achieve the routing according to the multi-dimensional QoS objective vector of the QoS objective model. Simulation results reveals that the algorithm works better than other existing algorithms in balancing the network resources, and applications with stringent QoS requirements could be run.
文摘The WHO World Health Assembly, and the most recent WHO World Health Report, have called for all health systems to move toward universal coverage. However, low-income countries have made little progress in this respect. We use existing evidence to describe the evolution of community-based health insurance in low-income countries through the three stages of basic model, enhanced model, and nationwide model. We have concluded that community-based health insurance development is a potential strategy to meet the urgent need for health financing in low-income countries. With careful planning and implementation, it is possible to adopt such evolutionary approach to achieve universal coverage by extending tax-based financing/social insurance characteristics to community-based health insurance schemes.
文摘With trends indicating increase in temperature and decrease in winter precipitation, a significant negative trend in snow-covered areas has been identified in the last decade in the Himalayas. This requires a quantitative analysis of the snow cover in the higher Himalayas. In this study, a nonlinear autoregressive exogenous model, an artificial neural network （ANN）, was deployed to predict the snow cover in the Kaligandaki river basin for the next 30 years. Observed climatic data, and snow covered area was used to train and test the model that captures the gross features of snow under the current climate scenario. The range of the likely effects of climate change on seasonal snow was assessed in the Himalayas using downscaled temperature and precipitation change projection from - HadCM3, a global circulation model to project future climate scenario, under the AIB emission scenario, which describes a future world of very rapid economic growth with balance use between fossil and non-fossil energy sources. The results show that there is a reduction of 9% to 46% of snow cover in different elevation zones during the considered time period, i.e., 2Oll to 2040. The 4700 m to 52oo m elevation zone is the most affected area and the area higher than 5200 m is the least affected. Overall, however, it is clear from the analysis that seasonal snow in the Kaligandaki basin is likely to be subject to substantialchanges due to the impact of climate change.
文摘In order to evaluate the danger of debris flow properly, eight factors were selected as the risk assess- ment indexes of the debris flow, namely the vertical slope, valley relative difference, hillside slope, area of ba- sin, loose solid material reserves, the path length of sediment supply probability, silting and scouring derrieking and vegetation coverage. The improved Analytic Hierarchy Process （ AHP ） method was used to obtain the weights of the factors; and the efficacy coefficient method was adopted to evaluate the risks of six typical debris flow gullies. According to the research, the improved AHP method not only avoids the subjectivity in the indi- vidual factor valuation by comparing two factors of each layer, but also makes the subsequent consistency check unnecessary.
基金supported by the National High-Tech Research & Devel-opment Program of China (Grant No.2009AA12Z140)the National Basic Research Program of China (Grant Nos. 2009CB421105 and 2007CB714401)+1 种基金the National Natural Science Foundation of China (Grant No. 40771144)SCYSF (Grant No. 08ZQ026-047)
文摘We developed a method for analyzing the change in snow cover using MODIS imagery.The method was applied to images of western Sichuan Province,China taken between 2002 and 2008.The model for extracting data on snow cover from MODIS images was created by spectral analysis.The multi-temporal snow layers were used to evaluate the temporal and spatial change in the area under snow cover between 2002 and 2008 using overlay and statistical analysis in ARCGIS.The majority(60.4%) of western Sichuan was rarely covered by snow and only 0.3% was covered by perennial snow in 2002.Snow cover was pri-marily distributed in Garzê and Aba.The area under snow cover was significantly and negatively correlated with the average monthly temperature and rainfall in 2002.The largest area under snow cover was measured in 2006 and the smallest was in 2007.Similarly,the area of snowmelt was the highest in 2006 and lowest in 2007.In general,the elevation of the snow line in-creased throughout the period 2002-2008;however,the elevation decreased in some years.Our results provide an important insight into the distribution of snow in this region,and may be useful for climate modeling and predicting the availability of water resources and the occurrence of floods and droughts.
文摘The author constructs the sheaf of generalized fundamental group of a topological space Xand obtains the relationship between its lst cohomology set and all covering spaces Of X undersuitable conditions imposed upon X.
