For lack of effective resource adjustment method, the supply-demand relationship of each resource in P2P content delivery system are often unbalanced. Especially after a popular content releasing, a burst of downloade...For lack of effective resource adjustment method, the supply-demand relationship of each resource in P2P content delivery system are often unbalanced. Especially after a popular content releasing, a burst of downloaders often can＇t find sufficient uploaders and their request may starve the upload capacity of server. Therefore the overall system QoS may be degraded. To tackle such issue, this paper proposes a download rate accelerate mechanism, called motivate mechanism. With it, the system can quickly find out the files becoming insufficient by monitoring the operating status of the files hourly, Then it promptly increase the number of copies of those files by using free rider nodes so that the whole system QoS is maintained and the system performance is improved. The experiment results on the practical operating system of Tencent demonstrated that the proposed mechanism increases the download rate, saves the traffic on the server and optimizes the system performance.展开更多
The resource allocation problem in data centre networks refers to a map of the workloads provided by the cloud users/tenants to the Substrate Network(SN)which are provided by the cloud providers.Existing studies consi...The resource allocation problem in data centre networks refers to a map of the workloads provided by the cloud users/tenants to the Substrate Network(SN)which are provided by the cloud providers.Existing studies consider the dynamic arrival and departure of the workloads,while the dynamics of the substrate are ignored.In this paper,we first propose the resource allocation with the dynamic SN,and denote it as GraphMap-DS.Then,we propose an efficient mapping algorithm for GraphMap-DS.The performance of the proposed algorithm is evaluated by performing simulation experiments.Our results show that the proposed algorithm can effectively solve the GraphMap-DS.展开更多
Indoor air quality and thermal comfort are important features of indoor environment. In this paper, a numerical simulation based on the k-ε model of CFD is used to analyze factors such as loading, exterior-protected ...Indoor air quality and thermal comfort are important features of indoor environment. In this paper, a numerical simulation based on the k-ε model of CFD is used to analyze factors such as loading, exterior-protected construction, blowing-in rate that play an important role in the temperature field and airflow field of the displacement ventilation system. Exterior-protected construction has little influence on indoor temperature distribution of displacement ventilation systems and the influence is limited only in a small area near the external wall when the indoor heat source is the main cooling load.The height of a room has little influence on indoor temperature field, and the temperature gradient of active region is basically unchanged. In the system combined with a displacement ventilation system and a cooling system, the height also has little influence. When the cooling load is high,the indoor heat source creates a strong convective plume, which will make the average indoor air age lower, the ventilation efficiency higher and the elimination of pollutant easier. Air supply rate plays an important role in displacement ventilation systems. The increase of air supply rate that can be realized by increasing the air supply velocity and enlarging the area of air inlet will increase the mass capability of the system and diminish the vertical temperature gradient. From the comparison between simulations and experiments, it is concluded that this simulation are creditable.展开更多
Traditional light bulbs （e.g., incandescent, fluorescent） use too much electricity, convert very little energy into light of sufficient quality and in their production use toxic contaminants. During the last few yea...Traditional light bulbs （e.g., incandescent, fluorescent） use too much electricity, convert very little energy into light of sufficient quality and in their production use toxic contaminants. During the last few years, a new type of light source, LED （light emitting diode） bulb, has gained increasing popularity and its costs are set to plunge even further. LED bulbs offer many advantages over traditional sources, and they can be used as a direct replacement to existing lighting. This paper will use a spreadsheet-based analysis with hourly solar data supplied by Ecotect to show that, the efficiency of LED installations can be increased when used in conjunction with photovoltaic modules, as the two generate （and use） DC （direct-current） electricity, thereby eliminating intermediate-level losses in the electronic circuitry. If a storage battery is included, the solar panels generate electricity during the times when the occupants are not necessarily using the lighting, but the stored electricity can be used to power the lighting when the energy is required. The latest results demonstrate that, a slight reduction in the required floor area to be lit allows the solar-battery-LED system to be implemented in small buildings using a storage battery size that is within the range of present commercial devices.展开更多
Water resources insufficiency is one of the bottlenecks that restrict sustainable socio-economic development in Ningbo city. Good handling of the relationship between water resources utilization and development is of ...Water resources insufficiency is one of the bottlenecks that restrict sustainable socio-economic development in Ningbo city. Good handling of the relationship between water resources utilization and development is of great significance for the realization of continuous economic growth and sustainable socio-economic development. This study systematically evaluated water resources utilization with respect to water supply and demand. Water resources development and utilization prospects and regional differences were then assessed at multiple scales, at both county/district and city level in Ningbo city, using the water resources carrying index. Results showed that：（1） The volume of water resources supply and consumption gradually rose each year, with surface water as the primary source and groundwater as the secondary source. Regarding consumption, industrial water consumption was the primary element, and domestic and environmental water consumption were the secondary elements. Even though the use of water resources for irrigation, secondary and, tertiary industry were becoming more efficient, comprehensive per capita water consumption was gradually increasing.（2） The water resources carrying index for Ningbo city fluctuated in the range of 4.51–23.35 during 2001–2015; the degree of water resource utilization and potential exploitation evaluation of water resources were not stable. The average value of the water resources carrying index was 11.68; the degree of utilization of water resources was very high, and the introduction of water from external water bodies was necessary, to the extent external source were available.（3） Future water resources exploitation will be quite difficult in Ningbo city, especially in Cixi county, Ningbo municipal district and Yuyao county. So the introduction of external water as a supplemental source will be required.展开更多
The Belt and Road Initiative(B&R Initiative)is a crucial strategy to promote regional sustainable development in the new era.However,the realization of the B&R Initiative faces huge challenges because of the d...The Belt and Road Initiative(B&R Initiative)is a crucial strategy to promote regional sustainable development in the new era.However,the realization of the B&R Initiative faces huge challenges because of the dual characteristics of a fragile eco-environment and strong dependence on ecological resources for economic development in the Belt and Road(B&R)countries.The ecological carrying capacity(ECC)is a crucial indicator for evaluating regional sustainable development.From the perspective of the relationship between the supply and consumption of ecological resources,this study uses net primary productivity data to measure the supply capacity of ecological resources,and it uses the agricultural production and trade data provided by the United Nations Food and Agriculture Organization to measure the level of ecological resource consumption.These supply and consumption data are then used to assess the ECC and ecological carrying status(ECS)of the B&R countries in 2017.The results show that:(1)The ECC of the B&R is 11.097 billion people;the ecosystem can also support 6.433 billion people,and the ECC is in a state of rich and surplus.(2)The ECS is polarized among the regions and countries along the B&R.Of the 65 countries,the ECC of 40 countries is in a rich and surplus state,mainly in Mid-East Europe and Southeast Asia,while the ECC of 19 countries is in severe overload,mainly in West Asia/Middle East.(3)Although the ecosystems still have ample carrying space in countries along the B&R,ecological protection is still facing enormous challenges during the implementation of the B&R Initiative combined with the internationally recognized ecological protection standards as well as the forecasts of the population and economic development.As the core content of building a new international trade network,the B&R Initiative will help to solve the spatial mismatch between the supply and consumption of ecological resources,which provides a new opportunity to coordinate the contradiction between the ecological protection and social demands of the B&R countries.展开更多
基金National Science Foundation Project of P.R.China，China Postdoctoral Science Foundation，the Fundamental Research Funds for the Central Universities
文摘For lack of effective resource adjustment method, the supply-demand relationship of each resource in P2P content delivery system are often unbalanced. Especially after a popular content releasing, a burst of downloaders often can＇t find sufficient uploaders and their request may starve the upload capacity of server. Therefore the overall system QoS may be degraded. To tackle such issue, this paper proposes a download rate accelerate mechanism, called motivate mechanism. With it, the system can quickly find out the files becoming insufficient by monitoring the operating status of the files hourly, Then it promptly increase the number of copies of those files by using free rider nodes so that the whole system QoS is maintained and the system performance is improved. The experiment results on the practical operating system of Tencent demonstrated that the proposed mechanism increases the download rate, saves the traffic on the server and optimizes the system performance.
基金supported by the National Basic Research of China(973 Program)under Grant No.2011CB302601the National Natural Science Foundation of China under Grants No.90818028,No.6903043,No.61202117the National High Technology Research and Development Program of China(863 Program)under Grant No.2012AA011201
文摘The resource allocation problem in data centre networks refers to a map of the workloads provided by the cloud users/tenants to the Substrate Network(SN)which are provided by the cloud providers.Existing studies consider the dynamic arrival and departure of the workloads,while the dynamics of the substrate are ignored.In this paper,we first propose the resource allocation with the dynamic SN,and denote it as GraphMap-DS.Then,we propose an efficient mapping algorithm for GraphMap-DS.The performance of the proposed algorithm is evaluated by performing simulation experiments.Our results show that the proposed algorithm can effectively solve the GraphMap-DS.
文摘Indoor air quality and thermal comfort are important features of indoor environment. In this paper, a numerical simulation based on the k-ε model of CFD is used to analyze factors such as loading, exterior-protected construction, blowing-in rate that play an important role in the temperature field and airflow field of the displacement ventilation system. Exterior-protected construction has little influence on indoor temperature distribution of displacement ventilation systems and the influence is limited only in a small area near the external wall when the indoor heat source is the main cooling load.The height of a room has little influence on indoor temperature field, and the temperature gradient of active region is basically unchanged. In the system combined with a displacement ventilation system and a cooling system, the height also has little influence. When the cooling load is high,the indoor heat source creates a strong convective plume, which will make the average indoor air age lower, the ventilation efficiency higher and the elimination of pollutant easier. Air supply rate plays an important role in displacement ventilation systems. The increase of air supply rate that can be realized by increasing the air supply velocity and enlarging the area of air inlet will increase the mass capability of the system and diminish the vertical temperature gradient. From the comparison between simulations and experiments, it is concluded that this simulation are creditable.
文摘Traditional light bulbs （e.g., incandescent, fluorescent） use too much electricity, convert very little energy into light of sufficient quality and in their production use toxic contaminants. During the last few years, a new type of light source, LED （light emitting diode） bulb, has gained increasing popularity and its costs are set to plunge even further. LED bulbs offer many advantages over traditional sources, and they can be used as a direct replacement to existing lighting. This paper will use a spreadsheet-based analysis with hourly solar data supplied by Ecotect to show that, the efficiency of LED installations can be increased when used in conjunction with photovoltaic modules, as the two generate （and use） DC （direct-current） electricity, thereby eliminating intermediate-level losses in the electronic circuitry. If a storage battery is included, the solar panels generate electricity during the times when the occupants are not necessarily using the lighting, but the stored electricity can be used to power the lighting when the energy is required. The latest results demonstrate that, a slight reduction in the required floor area to be lit allows the solar-battery-LED system to be implemented in small buildings using a storage battery size that is within the range of present commercial devices.
基金The National Key Research and Development Program of China(2016YFC0503500)Land planning project in Ningbo city(2016-2030)
文摘Water resources insufficiency is one of the bottlenecks that restrict sustainable socio-economic development in Ningbo city. Good handling of the relationship between water resources utilization and development is of great significance for the realization of continuous economic growth and sustainable socio-economic development. This study systematically evaluated water resources utilization with respect to water supply and demand. Water resources development and utilization prospects and regional differences were then assessed at multiple scales, at both county/district and city level in Ningbo city, using the water resources carrying index. Results showed that：（1） The volume of water resources supply and consumption gradually rose each year, with surface water as the primary source and groundwater as the secondary source. Regarding consumption, industrial water consumption was the primary element, and domestic and environmental water consumption were the secondary elements. Even though the use of water resources for irrigation, secondary and, tertiary industry were becoming more efficient, comprehensive per capita water consumption was gradually increasing.（2） The water resources carrying index for Ningbo city fluctuated in the range of 4.51–23.35 during 2001–2015; the degree of water resource utilization and potential exploitation evaluation of water resources were not stable. The average value of the water resources carrying index was 11.68; the degree of utilization of water resources was very high, and the introduction of water from external water bodies was necessary, to the extent external source were available.（3） Future water resources exploitation will be quite difficult in Ningbo city, especially in Cixi county, Ningbo municipal district and Yuyao county. So the introduction of external water as a supplemental source will be required.
基金The Strategic Priority Research ProgramChinese Academy of Sciences(XDA20010202)The National Key Research and Development Program of China(2016YFC0503505)。
文摘The Belt and Road Initiative(B&R Initiative)is a crucial strategy to promote regional sustainable development in the new era.However,the realization of the B&R Initiative faces huge challenges because of the dual characteristics of a fragile eco-environment and strong dependence on ecological resources for economic development in the Belt and Road(B&R)countries.The ecological carrying capacity(ECC)is a crucial indicator for evaluating regional sustainable development.From the perspective of the relationship between the supply and consumption of ecological resources,this study uses net primary productivity data to measure the supply capacity of ecological resources,and it uses the agricultural production and trade data provided by the United Nations Food and Agriculture Organization to measure the level of ecological resource consumption.These supply and consumption data are then used to assess the ECC and ecological carrying status(ECS)of the B&R countries in 2017.The results show that:(1)The ECC of the B&R is 11.097 billion people;the ecosystem can also support 6.433 billion people,and the ECC is in a state of rich and surplus.(2)The ECS is polarized among the regions and countries along the B&R.Of the 65 countries,the ECC of 40 countries is in a rich and surplus state,mainly in Mid-East Europe and Southeast Asia,while the ECC of 19 countries is in severe overload,mainly in West Asia/Middle East.(3)Although the ecosystems still have ample carrying space in countries along the B&R,ecological protection is still facing enormous challenges during the implementation of the B&R Initiative combined with the internationally recognized ecological protection standards as well as the forecasts of the population and economic development.As the core content of building a new international trade network,the B&R Initiative will help to solve the spatial mismatch between the supply and consumption of ecological resources,which provides a new opportunity to coordinate the contradiction between the ecological protection and social demands of the B&R countries.
