Due to the mobility of mobile hosts,checkpoints and message logs of the computing process may disperseover different mobile support stations in the checkpointing and rollback recovery protocol for mobilecomputing.Thre...Due to the mobility of mobile hosts,checkpoints and message logs of the computing process may disperseover different mobile support stations in the checkpointing and rollback recovery protocol for mobilecomputing.Three existing checkpoint handoff schemes do not give well consideration to the efficiency offailure-free process execution and the recovery speed of the failure process at the same time.A dynamicadaptive handoff management of the checkpointing and rollback recovery protocol for mobile computing isproposed in this paper.According to the individual feature and current state of each mobile host,differentimplementations are selected dynamically to complete the handoff process upon the handoff event.Performance analyses show that the proposed handoff management incurs a low loss of performance duringfailure-free and achieves a quick recovery upon the process fault.展开更多
The research investigated the relationship between students' motivation, autonomy, self-concept and their performance in CALL listening, and the effectiveness of CALL (Computer Assisted Language Learning). A quest...The research investigated the relationship between students' motivation, autonomy, self-concept and their performance in CALL listening, and the effectiveness of CALL (Computer Assisted Language Learning). A questionnaire was administered to more than 200 EFL students and their CALL course grades and those of previous traditional listening tests were collected for analysis. Findings show that CALL listening is effective in aiding language learning; students' motivation, autonomy, self-concept and their listening performance through CALL may have significant effects on one another; that degree of motivation, autonomy and self-concept influences the effects they have; and that, ideally, CALL listening may take the place of traditional classroom listening teaching.展开更多
The effects of turbulent intensity and vortex scale of simulated natural wind on performance of a horizontal axis wind turbine(HAWT) are mainly investigated in this paper. In particular, the unsteadiness and turbulenc...The effects of turbulent intensity and vortex scale of simulated natural wind on performance of a horizontal axis wind turbine(HAWT) are mainly investigated in this paper. In particular, the unsteadiness and turbulence of wind in Japan are stronger than ones in Europe and North America in general. Hence, Japanese engineers should take account of the velocity unsteadiness of natural wind at installed open-air location to design a higher performance wind turbine. Using the originally designed five wind turbines on the basis of NACA and MEL blades, the dependencies of the wind frequency and vortex scale of the simulated natural wind are presented. As the results, the power coefficient of the newly designed MEL3-type rotor in the simulated natural wind is 130% larger than one in steady wind.展开更多
基金Supported by the National Natural Science Foundation of China (No. 60873138)Postdoctoral Scientific Research Foundation of Heilongjiang (No. LBH-008124)the Fundamental Research Funds for the Central Universities (No. HEUCFT1007)
文摘Due to the mobility of mobile hosts,checkpoints and message logs of the computing process may disperseover different mobile support stations in the checkpointing and rollback recovery protocol for mobilecomputing.Three existing checkpoint handoff schemes do not give well consideration to the efficiency offailure-free process execution and the recovery speed of the failure process at the same time.A dynamicadaptive handoff management of the checkpointing and rollback recovery protocol for mobile computing isproposed in this paper.According to the individual feature and current state of each mobile host,differentimplementations are selected dynamically to complete the handoff process upon the handoff event.Performance analyses show that the proposed handoff management incurs a low loss of performance duringfailure-free and achieves a quick recovery upon the process fault.
文摘The research investigated the relationship between students' motivation, autonomy, self-concept and their performance in CALL listening, and the effectiveness of CALL (Computer Assisted Language Learning). A questionnaire was administered to more than 200 EFL students and their CALL course grades and those of previous traditional listening tests were collected for analysis. Findings show that CALL listening is effective in aiding language learning; students' motivation, autonomy, self-concept and their listening performance through CALL may have significant effects on one another; that degree of motivation, autonomy and self-concept influences the effects they have; and that, ideally, CALL listening may take the place of traditional classroom listening teaching.
基金supported by Hatakeyama Grant-in-Aid(2014)of Turbomachinery of Japanthe support of Dr.Hikaru Matsumiya and Dr.Tetsuya Kogaki(National Institute of Advanced Industrial Science and Technology of Japan)for providing MEL blade data
文摘The effects of turbulent intensity and vortex scale of simulated natural wind on performance of a horizontal axis wind turbine(HAWT) are mainly investigated in this paper. In particular, the unsteadiness and turbulence of wind in Japan are stronger than ones in Europe and North America in general. Hence, Japanese engineers should take account of the velocity unsteadiness of natural wind at installed open-air location to design a higher performance wind turbine. Using the originally designed five wind turbines on the basis of NACA and MEL blades, the dependencies of the wind frequency and vortex scale of the simulated natural wind are presented. As the results, the power coefficient of the newly designed MEL3-type rotor in the simulated natural wind is 130% larger than one in steady wind.
