A hierarchical clustered BitTorrent （CBT） system is proposed to improve the file sharing perior-mance of the BitTorrent system, in which peers are grouped into clusters in a large-scale BitTorrent-hke underlying ove...A hierarchical clustered BitTorrent （CBT） system is proposed to improve the file sharing perior-mance of the BitTorrent system, in which peers are grouped into clusters in a large-scale BitTorrent-hke underlying overlay network in such a way that clusters are evenly distributed and that the peers within the cluster are relatively close to each other. A fluid model is developed to compare the performance of the proposed CBT system with the BitTorrent system, and the result shows that the CBT system can effectively improve the performance of the system. Simulation results also demonstrate that the CBT system improves the system scalabihty and efficiency while retaining the robustness and incentives of the original BitTorrent paradigm.展开更多
How can choreography and physical theatre pieces continue to perpetuate the work after rendering？ How to preserve their aura, their dynamics, and their ephemeral and genuine nature, as Walter Benjamin said？ In 1936,...How can choreography and physical theatre pieces continue to perpetuate the work after rendering？ How to preserve their aura, their dynamics, and their ephemeral and genuine nature, as Walter Benjamin said？ In 1936, Benjamin already anticipated in The Work of Art in the Age of lts Technological Reproducibility that something is missing even in the best-finished reproduction. And memories of dance and physical theatre are intricate. The question is how to create a type of documentation that does not betray the vital flow of the event-based phenomenon. In this short article we will see a series of choreographic and performance artists like Esther Ferrer, Ayara Hern^indez Holz, and Olga de Soto who claimed a new form of organic documentation, making it turn performance or memory of viewers. Other creators as the company La Fura dels Baus claim documentation as spectacle and others on the opposite side, as Tino Sehgal propose radically non documentation of their work. Precisely, these different positions coincide with those of thinkers like Peggy Phelan, Sarah Bay-Cheng, or Paula Caspao who respect to a range of documentation and how it can never replace the live art.展开更多
Based on the analysis about the hydrogeological conditions and engineering geological conditions, this paper makes analysis on the possible risks of the deep overlying stratum foundation and establishes the risk evalu...Based on the analysis about the hydrogeological conditions and engineering geological conditions, this paper makes analysis on the possible risks of the deep overlying stratum foundation and establishes the risk evaluation index system during the foundation operating period. Such methods as analytic hierarchy process （AHP） , Delphi method and fuzzy comprehensive evaluation method are adopted to make the quantitative analysis on the risk factors and establish the risk judgment model. According to the actual engineering of Taizhou Bridge, the paper evaluates the risk of the foundation during the operating period at the condition of deep overlying stratum. The evaluation results can provide the reference for the risk management of the bridge foundation durin~ the ooerating period.展开更多
With an increase of mining the upper limits under unconsolidated aquifers, dewatering of the bottom aquifer of the Quaternary system has become a major method to avoid water and sand inrushes.In the 8th District of th...With an increase of mining the upper limits under unconsolidated aquifers, dewatering of the bottom aquifer of the Quaternary system has become a major method to avoid water and sand inrushes.In the 8th District of the Taiping Coal Mine in south-western Shandong province, the bottom aquifer of the Quaternary system is moderate to excellent in water-yielding capacity.The base rock above the coal seam is very thin in the concealed coal field of the Carboniferous and Permian systems.Therefore, a comprehensive dewatering plan from both the ground surface and the panel was proposed to lower the groundwater level in order to ensure mining safety.According to the hydrogeologic conditions of the 8th District, we established a numerical model so that we could simulate the groundwater flow in the dewatering process.We obtained the simulation parameters from previous data using backward modeling, such as the average coefficient of permeability of 12 m/d and the elastic storage coefficient of 0.002.From the same model, we predicted the movement of groundwater and water level variables and obtained the visible effect of the dewatering project.Despite the overburden failure during mining, no water and/or sand inrush occurred because the groundwater level in the bottom aquifer was lowered to a safe water level.展开更多
基金the National High Technology Research and Development Programme of China(No2004AA104280,2006AA01Z172)
文摘A hierarchical clustered BitTorrent （CBT） system is proposed to improve the file sharing perior-mance of the BitTorrent system, in which peers are grouped into clusters in a large-scale BitTorrent-hke underlying overlay network in such a way that clusters are evenly distributed and that the peers within the cluster are relatively close to each other. A fluid model is developed to compare the performance of the proposed CBT system with the BitTorrent system, and the result shows that the CBT system can effectively improve the performance of the system. Simulation results also demonstrate that the CBT system improves the system scalabihty and efficiency while retaining the robustness and incentives of the original BitTorrent paradigm.
文摘How can choreography and physical theatre pieces continue to perpetuate the work after rendering？ How to preserve their aura, their dynamics, and their ephemeral and genuine nature, as Walter Benjamin said？ In 1936, Benjamin already anticipated in The Work of Art in the Age of lts Technological Reproducibility that something is missing even in the best-finished reproduction. And memories of dance and physical theatre are intricate. The question is how to create a type of documentation that does not betray the vital flow of the event-based phenomenon. In this short article we will see a series of choreographic and performance artists like Esther Ferrer, Ayara Hern^indez Holz, and Olga de Soto who claimed a new form of organic documentation, making it turn performance or memory of viewers. Other creators as the company La Fura dels Baus claim documentation as spectacle and others on the opposite side, as Tino Sehgal propose radically non documentation of their work. Precisely, these different positions coincide with those of thinkers like Peggy Phelan, Sarah Bay-Cheng, or Paula Caspao who respect to a range of documentation and how it can never replace the live art.
基金National Science and Technology Support Program of China(No.2009BAG15B02)Key Programs for Science and Technology Development of Chinese Transportation Industry(No.2008-353-332-180)
文摘Based on the analysis about the hydrogeological conditions and engineering geological conditions, this paper makes analysis on the possible risks of the deep overlying stratum foundation and establishes the risk evaluation index system during the foundation operating period. Such methods as analytic hierarchy process （AHP） , Delphi method and fuzzy comprehensive evaluation method are adopted to make the quantitative analysis on the risk factors and establish the risk judgment model. According to the actual engineering of Taizhou Bridge, the paper evaluates the risk of the foundation during the operating period at the condition of deep overlying stratum. The evaluation results can provide the reference for the risk management of the bridge foundation durin~ the ooerating period.
基金Projects 40372123, 40772192 supported by the National Natural Science Foundation of ChinaNCET-04-0486 by the Program for New Century Excellent Talents in University of China2007CB209400 by the National Basic Research Program of China
文摘With an increase of mining the upper limits under unconsolidated aquifers, dewatering of the bottom aquifer of the Quaternary system has become a major method to avoid water and sand inrushes.In the 8th District of the Taiping Coal Mine in south-western Shandong province, the bottom aquifer of the Quaternary system is moderate to excellent in water-yielding capacity.The base rock above the coal seam is very thin in the concealed coal field of the Carboniferous and Permian systems.Therefore, a comprehensive dewatering plan from both the ground surface and the panel was proposed to lower the groundwater level in order to ensure mining safety.According to the hydrogeologic conditions of the 8th District, we established a numerical model so that we could simulate the groundwater flow in the dewatering process.We obtained the simulation parameters from previous data using backward modeling, such as the average coefficient of permeability of 12 m/d and the elastic storage coefficient of 0.002.From the same model, we predicted the movement of groundwater and water level variables and obtained the visible effect of the dewatering project.Despite the overburden failure during mining, no water and/or sand inrush occurred because the groundwater level in the bottom aquifer was lowered to a safe water level.
