通过科学建模,设计数据中心不间断电源系统UPS(Uninterruptible Power System)配置软件,从冗余、容量、效率、成本、装机面积等参数入手,结合实际运行数据库,为数据中心UPS不间断电源系统设计人员提供一个有效的参考选择。从总体拥有成...通过科学建模,设计数据中心不间断电源系统UPS(Uninterruptible Power System)配置软件,从冗余、容量、效率、成本、装机面积等参数入手,结合实际运行数据库,为数据中心UPS不间断电源系统设计人员提供一个有效的参考选择。从总体拥有成本TCO(Total Cost of Ownership)全生命周期角度,不仅考虑前期投资,而且对后期维护成本、节能运行进行综合的考虑。展开更多
By analyzing the existing prefix-tree data structure, an improved pattern tree was introduced for processing new transactions. It firstly stored transactions in a lexicographic order tree and then restructured the tre...By analyzing the existing prefix-tree data structure, an improved pattern tree was introduced for processing new transactions. It firstly stored transactions in a lexicographic order tree and then restructured the tree by sorting each path in a frequency-descending order. While updating the improved pattern tree, there was no need to rescan the entire new database or reconstruct a new tree for incremental updating. A test was performed on synthetic dataset T1014D100K with 100 000 transactions and 870 items. Experimental results show that the smaller the minimum sup- port threshold, the faster the improved pattern tree achieves over CanTree for all datasets. As the minimum support threshold increased from 2% to 3.5%, the runtime decreased from 452.71 s to 186.26 s. Meanwhile, the runtime re- quired by CanTree decreased from 1 367.03 s to 432.19 s. When the database was updated, the execution time of im- proved pattern tree consisted of construction of original improved pattern trees and reconstruction of initial tree. The experiment results showed that the runtime was saved by about 15% compared with that of CanTree. As the number of transactions increased, the runtime of improved pattern tree was about 25% shorter than that of FP-tree. The improved pattern tree also required less memory than CanTree.展开更多
Real traffic information was analyzed in the statistical characteristics and approximated as a Gaussian time series. A data source model, called two states constant bit rate (TSCBR), was proposed in dynamic traffic mo...Real traffic information was analyzed in the statistical characteristics and approximated as a Gaussian time series. A data source model, called two states constant bit rate (TSCBR), was proposed in dynamic traffic monitoring sensor networks. Analysis of autocorrelation of the models shows that the proposed TSCBR model matches with the statistical characteristics of real data source closely. To further verify the validity of the TSCBR data source model, the performance metrics of power consumption and network lifetime was studied in the evaluation of sensor media access control (SMAC) algorithm. The simulation results show that compared with traditional data source models, TSCBR model can significantly improve accuracy of the algorithm evaluation.展开更多
Various technologies have recently been developed for high-speed railways, in order to boost commercial speeds from 300 km.h： to 400 km.h-1. Among these technologies, this paper introduces the 400 km-h-1 class curren...Various technologies have recently been developed for high-speed railways, in order to boost commercial speeds from 300 km.h： to 400 km.h-1. Among these technologies, this paper introduces the 400 km-h-1 class current collection performance evaluation methods that have been developed and demonstrated by Korea. Specifically, this paper reports details of the video-based monitoring techniques that have been adopted to inspect the stability of overhead contact line （OCL） components at 400 km.h-1 without direct contact with any components of the power supply system. Unlike conventional OCL monitoring systems, which detect contact wire positions using either laser sensors or line cameras, the developed system measures parameters in the active state by video data. According to experimental results that were obtained at a field-test site established at a commercial line, it is claimed that the proposed mea- surement system is capable of effectively measuring OCL parameters.展开更多
Due to the use of mechanical and electrical equipments in different buildings during construction phase, energy consumption produces large amounts of carbon emissions.Based on the energy use of China, we established a...Due to the use of mechanical and electrical equipments in different buildings during construction phase, energy consumption produces large amounts of carbon emissions.Based on the energy use of China, we established a formula that was applicable to carbon-emission calculation, and discussed carbon-emission characteristics of concrete structures and steel construction.Owing to the difference of electrical and mechanical equipment used in construction phase, the results show that under the same conditions, the carbon emission intensity of a concrete structure building is much higher than that of a steel building.At last, we also put forward some emission reduction measures based on the calculation data of different buildings.展开更多
Through the comparison of various acquisition technology and related technology theory of the existing scheme, the paper analyze and design the power battery testing platform of the data acquisition system, and give t...Through the comparison of various acquisition technology and related technology theory of the existing scheme, the paper analyze and design the power battery testing platform of the data acquisition system, and give the research design scheme of the utility model through the design of the software on PC and CAN bus, which makes the full synchronization requirements acquisition unit; improve the linearity and stability of total voltage and current acquisition by the integrated circuit, and improve the system sampling rate, effectively complete the corresponding index. Finally, through experimental verification, to ensure the completion of the technical indicators.展开更多
文摘通过科学建模,设计数据中心不间断电源系统UPS(Uninterruptible Power System)配置软件,从冗余、容量、效率、成本、装机面积等参数入手,结合实际运行数据库,为数据中心UPS不间断电源系统设计人员提供一个有效的参考选择。从总体拥有成本TCO(Total Cost of Ownership)全生命周期角度,不仅考虑前期投资,而且对后期维护成本、节能运行进行综合的考虑。
基金Supported by National Natural Science Foundation of China (No.50975193)Specialized Research Fund for Doctoral Program of Higher Education of China (No.20060056016)
文摘By analyzing the existing prefix-tree data structure, an improved pattern tree was introduced for processing new transactions. It firstly stored transactions in a lexicographic order tree and then restructured the tree by sorting each path in a frequency-descending order. While updating the improved pattern tree, there was no need to rescan the entire new database or reconstruct a new tree for incremental updating. A test was performed on synthetic dataset T1014D100K with 100 000 transactions and 870 items. Experimental results show that the smaller the minimum sup- port threshold, the faster the improved pattern tree achieves over CanTree for all datasets. As the minimum support threshold increased from 2% to 3.5%, the runtime decreased from 452.71 s to 186.26 s. Meanwhile, the runtime re- quired by CanTree decreased from 1 367.03 s to 432.19 s. When the database was updated, the execution time of im- proved pattern tree consisted of construction of original improved pattern trees and reconstruction of initial tree. The experiment results showed that the runtime was saved by about 15% compared with that of CanTree. As the number of transactions increased, the runtime of improved pattern tree was about 25% shorter than that of FP-tree. The improved pattern tree also required less memory than CanTree.
基金The National Natural Science Foundation ofChia(No60372076)The Important cienceand Technology Key Item of Shanghai Science and Technology Bureau ( No05dz15004)
文摘Real traffic information was analyzed in the statistical characteristics and approximated as a Gaussian time series. A data source model, called two states constant bit rate (TSCBR), was proposed in dynamic traffic monitoring sensor networks. Analysis of autocorrelation of the models shows that the proposed TSCBR model matches with the statistical characteristics of real data source closely. To further verify the validity of the TSCBR data source model, the performance metrics of power consumption and network lifetime was studied in the evaluation of sensor media access control (SMAC) algorithm. The simulation results show that compared with traditional data source models, TSCBR model can significantly improve accuracy of the algorithm evaluation.
文摘Various technologies have recently been developed for high-speed railways, in order to boost commercial speeds from 300 km.h： to 400 km.h-1. Among these technologies, this paper introduces the 400 km-h-1 class current collection performance evaluation methods that have been developed and demonstrated by Korea. Specifically, this paper reports details of the video-based monitoring techniques that have been adopted to inspect the stability of overhead contact line （OCL） components at 400 km.h-1 without direct contact with any components of the power supply system. Unlike conventional OCL monitoring systems, which detect contact wire positions using either laser sensors or line cameras, the developed system measures parameters in the active state by video data. According to experimental results that were obtained at a field-test site established at a commercial line, it is claimed that the proposed mea- surement system is capable of effectively measuring OCL parameters.
基金Funded by Regional Transportation Integration Technology of FAFU (No.Pytd 12006)Science and Technology project of Fujian Education Department (No.JB 11046)
文摘Due to the use of mechanical and electrical equipments in different buildings during construction phase, energy consumption produces large amounts of carbon emissions.Based on the energy use of China, we established a formula that was applicable to carbon-emission calculation, and discussed carbon-emission characteristics of concrete structures and steel construction.Owing to the difference of electrical and mechanical equipment used in construction phase, the results show that under the same conditions, the carbon emission intensity of a concrete structure building is much higher than that of a steel building.At last, we also put forward some emission reduction measures based on the calculation data of different buildings.
文摘Through the comparison of various acquisition technology and related technology theory of the existing scheme, the paper analyze and design the power battery testing platform of the data acquisition system, and give the research design scheme of the utility model through the design of the software on PC and CAN bus, which makes the full synchronization requirements acquisition unit; improve the linearity and stability of total voltage and current acquisition by the integrated circuit, and improve the system sampling rate, effectively complete the corresponding index. Finally, through experimental verification, to ensure the completion of the technical indicators.
