Although the encryption of network packets significantly increases privacy, the density of the traffic can still provide useful information to the observer, and maybe results in the breach of confidentiality. In this ...Although the encryption of network packets significantly increases privacy, the density of the traffic can still provide useful information to the observer, and maybe results in the breach of confidentiality. In this paper, we address issues related to hiding information in self-similar network, which is proved to be similar with modern communication network. And a statistical hiding algorithm is proposed for traffic padding. The figures and the comparison of Hurst Parameters before and after traffic padding, show the effective performance of the algorithm.展开更多
Transport system is a time-varying, huge and complex system. In order to have the traffic management department make pre-appropriate traffic management measures to adjust the traffic management control program, and re...Transport system is a time-varying, huge and complex system. In order to have the traffic management department make pre-appropriate traffic management measures to adjust the traffic management control program, and release travel information to travelers, to provide optimal path options to ensure that the transport system operates efficiently and safely, we have to monitor the changing of the state of road traffic and to accurately evaluate the state of the traffic, then to predict the future state of traffic. This paper represents the construction of the road traffic flow simulation including the logical structure and the physical structure, and introduces the system functions of forecasting system in Beijing.展开更多
Transport risk assessment for the environment has two important aspects--problem solving model and solution veracity. Problem solving model is larger understanding of tasks interconnection, which represents in itself ...Transport risk assessment for the environment has two important aspects--problem solving model and solution veracity. Problem solving model is larger understanding of tasks interconnection, which represents in itself partial solution of general risk assessment. Veracity of solution means how the results are consistent with the reality. By researching of both aspects, it rises many unanswered questions. It is concerned about verification and validation of risk assessment results. By risk assessment for the environment it is possible to meet wide variety of more or less good soluble problems. It exists simple problems based on risk assessment of common traffic accidents connected with service charge outflow. On the other site, it exists complex problems of risk assessment connected with dangerous goods transport by traffic or pipelines. By simple problems solving there are not many questions about risk assessment veracity. It is possible to determine traffic accidents frequencies and service charge outflows consequences on the basis of examined events in transportation with great veracity. By complex problems the situation is quite different. The frequencies of large accidents are very low but the consequences for the environment may be large. Both are encumbered by large level of uncertainty. That is why the question is rising. To what degree, it is in these cases correct to make decision based on risk assessment.展开更多
The performance of a BTES （borehole thermal energy storage） system is primarily governed by ground heat flux, soil thermal properties and groundwater conditions. However, the design of the heat exchanger used within...The performance of a BTES （borehole thermal energy storage） system is primarily governed by ground heat flux, soil thermal properties and groundwater conditions. However, the design of the heat exchanger used within the BTES system can also make a significant difference in the efficiency of the system. A thermal response test was carded out for a Kelix GHE （ground heat exchanger） system, the latest innovation in geothermal ground loop construction, on an Ecofarm in the town of Caledon East, Ontario, Canada. In addition, a verifying test was performed for a CEES （conventional earth energy system） located 6 m away from the Kelix GHE. The boreholes for these two different heat exchanger designs were drilled with the same diameter, to the same depth and were located in the same/identical geo-hydrological conditions. The response test provided the effective average of undisturbed ground temperature, geothermal properties including thermal conductivity, heat capacity and thermal resistance between the fluid and the borehole wall. The mathematical analysis method used for the response test is presented here. Results of the response test were verified, analyzed and are further discussed.展开更多
Loop heat pipes （LHPs） were designed for the alpha magnetic spectrometer （AMS-02） to dissipate heat from the cryocoolers. A bypass valve is applied to the LHP to keep the cryocooler temperature above its limit （...Loop heat pipes （LHPs） were designed for the alpha magnetic spectrometer （AMS-02） to dissipate heat from the cryocoolers. A bypass valve is applied to the LHP to keep the cryocooler temperature above its limit （-20℃） in cold environment. Extensive experiments were performed on operation characteristics of LHPs with the bypass valve for AMS-02 during thermal vacuum and thermal balance （TVTB） test. We found that the bypass valve can start up successfully in cold environment. With the bypass valve, the evaporator temperature is stable and can meet the requirement of the cryocooler. We analyzed three operating modes of the bypass valve. Set point temperature and regulation temperature shifts were observed and their relations with the bypass valve temperature were given.展开更多
基金Sponsored by the Program for New Excellent Talents in University(Grant No.NZCT2004-0332)
文摘Although the encryption of network packets significantly increases privacy, the density of the traffic can still provide useful information to the observer, and maybe results in the breach of confidentiality. In this paper, we address issues related to hiding information in self-similar network, which is proved to be similar with modern communication network. And a statistical hiding algorithm is proposed for traffic padding. The figures and the comparison of Hurst Parameters before and after traffic padding, show the effective performance of the algorithm.
基金Key Projects in Science & Technology Pillar Program in 2007 in Beijing (No.D07020601400705)
文摘Transport system is a time-varying, huge and complex system. In order to have the traffic management department make pre-appropriate traffic management measures to adjust the traffic management control program, and release travel information to travelers, to provide optimal path options to ensure that the transport system operates efficiently and safely, we have to monitor the changing of the state of road traffic and to accurately evaluate the state of the traffic, then to predict the future state of traffic. This paper represents the construction of the road traffic flow simulation including the logical structure and the physical structure, and introduces the system functions of forecasting system in Beijing.
文摘Transport risk assessment for the environment has two important aspects--problem solving model and solution veracity. Problem solving model is larger understanding of tasks interconnection, which represents in itself partial solution of general risk assessment. Veracity of solution means how the results are consistent with the reality. By researching of both aspects, it rises many unanswered questions. It is concerned about verification and validation of risk assessment results. By risk assessment for the environment it is possible to meet wide variety of more or less good soluble problems. It exists simple problems based on risk assessment of common traffic accidents connected with service charge outflow. On the other site, it exists complex problems of risk assessment connected with dangerous goods transport by traffic or pipelines. By simple problems solving there are not many questions about risk assessment veracity. It is possible to determine traffic accidents frequencies and service charge outflows consequences on the basis of examined events in transportation with great veracity. By complex problems the situation is quite different. The frequencies of large accidents are very low but the consequences for the environment may be large. Both are encumbered by large level of uncertainty. That is why the question is rising. To what degree, it is in these cases correct to make decision based on risk assessment.
文摘The performance of a BTES （borehole thermal energy storage） system is primarily governed by ground heat flux, soil thermal properties and groundwater conditions. However, the design of the heat exchanger used within the BTES system can also make a significant difference in the efficiency of the system. A thermal response test was carded out for a Kelix GHE （ground heat exchanger） system, the latest innovation in geothermal ground loop construction, on an Ecofarm in the town of Caledon East, Ontario, Canada. In addition, a verifying test was performed for a CEES （conventional earth energy system） located 6 m away from the Kelix GHE. The boreholes for these two different heat exchanger designs were drilled with the same diameter, to the same depth and were located in the same/identical geo-hydrological conditions. The response test provided the effective average of undisturbed ground temperature, geothermal properties including thermal conductivity, heat capacity and thermal resistance between the fluid and the borehole wall. The mathematical analysis method used for the response test is presented here. Results of the response test were verified, analyzed and are further discussed.
基金supported by the Major Project of Technology Transfer of Shandong Province (Grant No. 2009ZHZX1A1105)
文摘Loop heat pipes （LHPs） were designed for the alpha magnetic spectrometer （AMS-02） to dissipate heat from the cryocoolers. A bypass valve is applied to the LHP to keep the cryocooler temperature above its limit （-20℃） in cold environment. Extensive experiments were performed on operation characteristics of LHPs with the bypass valve for AMS-02 during thermal vacuum and thermal balance （TVTB） test. We found that the bypass valve can start up successfully in cold environment. With the bypass valve, the evaporator temperature is stable and can meet the requirement of the cryocooler. We analyzed three operating modes of the bypass valve. Set point temperature and regulation temperature shifts were observed and their relations with the bypass valve temperature were given.
