This paper describes how to use medium access control (MAC) isolation to enhance management performance in public wireless LAN (PWLAN). To comply with the IEEE 802.11 standards, a scheme to implement MAC isolation in ...This paper describes how to use medium access control (MAC) isolation to enhance management performance in public wireless LAN (PWLAN). To comply with the IEEE 802.11 standards, a scheme to implement MAC isolation in WLAN access points by re-designing the Distribution_Service component of the MAC state machine is proposed. A variable named dotl 1 Isolation is defined to determine whether the MAC level communication between wireless stations in the same BSS is permitted or not. Finally, a design solution based on MPC860 hardware and embedded Linux software for PWLAN access point is specified. The simulation results of MAC isolation for PWLAN show that the proposed scheme is feasible and effective.展开更多
At GCC 2003 in Shanghai in December 2003, a panel discussion was held on thefuture of grid computing and on the role of the Globus Toolkit in future grid standards. Panelistsinclude Andrew Chien (UCSD, USA), Wolfgang ...At GCC 2003 in Shanghai in December 2003, a panel discussion was held on thefuture of grid computing and on the role of the Globus Toolkit in future grid standards. Panelistsinclude Andrew Chien (UCSD, USA), Wolfgang Gentzsch (Sun), Francis Lau (HKU, China), Carl Kesselman(USC, USA), Satoshi Matsuoka (TIT, Japan), Xian-He Sun (IIT, USA), Richard Wirt (Intel), Liang-JieZhang (IBM Research), Song-Nian Zhou (Platform Computing), and Zhi-Wei Xu (ICT, China), with Hai Jin(HUST, China) served as the coordinator. The panel talks were stimulating and well received. Threeof the panel talk notes are selected and included in this viewpoint.展开更多
A new type of solid-conversion gas detector is investigated for high energy X-ray industrial computed tomography (HECT). The conversion efficiency is calculated by using the EGSnrc Monte Carlo code on the Linux platfo...A new type of solid-conversion gas detector is investigated for high energy X-ray industrial computed tomography (HECT). The conversion efficiency is calculated by using the EGSnrc Monte Carlo code on the Linux platform to simulate the transport process of photons and electrons in the detector. The simulation results show that the conversion efficiency could be more than 65%, if the X-ray beam width is less than about 0.2 mm, and a tungsten slab with 0.2 mm thickness and 30 mm length is employed as a radiation conversion medium. Meanwhile the results indicate that this new detector has higher conversion efficiency as well as less volume. Theoretically this new kind of detector could take place of the traditional scintillation detector for HECT.展开更多
文摘This paper describes how to use medium access control (MAC) isolation to enhance management performance in public wireless LAN (PWLAN). To comply with the IEEE 802.11 standards, a scheme to implement MAC isolation in WLAN access points by re-designing the Distribution_Service component of the MAC state machine is proposed. A variable named dotl 1 Isolation is defined to determine whether the MAC level communication between wireless stations in the same BSS is permitted or not. Finally, a design solution based on MPC860 hardware and embedded Linux software for PWLAN access point is specified. The simulation results of MAC isolation for PWLAN show that the proposed scheme is feasible and effective.
文摘At GCC 2003 in Shanghai in December 2003, a panel discussion was held on thefuture of grid computing and on the role of the Globus Toolkit in future grid standards. Panelistsinclude Andrew Chien (UCSD, USA), Wolfgang Gentzsch (Sun), Francis Lau (HKU, China), Carl Kesselman(USC, USA), Satoshi Matsuoka (TIT, Japan), Xian-He Sun (IIT, USA), Richard Wirt (Intel), Liang-JieZhang (IBM Research), Song-Nian Zhou (Platform Computing), and Zhi-Wei Xu (ICT, China), with Hai Jin(HUST, China) served as the coordinator. The panel talks were stimulating and well received. Threeof the panel talk notes are selected and included in this viewpoint.
基金supported by the National Natural Science Foundation of China (No.60672098)the Tackling Key Problems of Science and Technology of ChongQing (No.CSTC2009AC3047)
文摘A new type of solid-conversion gas detector is investigated for high energy X-ray industrial computed tomography (HECT). The conversion efficiency is calculated by using the EGSnrc Monte Carlo code on the Linux platform to simulate the transport process of photons and electrons in the detector. The simulation results show that the conversion efficiency could be more than 65%, if the X-ray beam width is less than about 0.2 mm, and a tungsten slab with 0.2 mm thickness and 30 mm length is employed as a radiation conversion medium. Meanwhile the results indicate that this new detector has higher conversion efficiency as well as less volume. Theoretically this new kind of detector could take place of the traditional scintillation detector for HECT.
