This paper presents Isotope, an efficient, locality aware, fault-tolerant, and decentralized scheme for data location in distributed networks. This scheme is designed based on the mathematical model of decentralized l...This paper presents Isotope, an efficient, locality aware, fault-tolerant, and decentralized scheme for data location in distributed networks. This scheme is designed based on the mathematical model of decentralized location services and thus has provable correctness and performance. In Isotope, each node needs to only maintain linkage information with about O(log n) other nodes and any node can be reached within O(log n) routing hops. Compared with other related schemes, Isotope’s average locating path length is only half that of Chord, and its locating performance and locality-awareness are similar to that of Pastry and Tapestry. In addition, Isotope is more suitable for constantly changing networks because it needs to exchange only O(log n) O(log n) messages to update the routing information for nodes arrival, departure and failure.展开更多
Buried object which exists at extremely shallow underground can be detected by using an acoustic vibration and a SLDV （scanning laser Doppler vibrometer）. Non-contact acoustic exploration can be realized by using ai...Buried object which exists at extremely shallow underground can be detected by using an acoustic vibration and a SLDV （scanning laser Doppler vibrometer）. Non-contact acoustic exploration can be realized by using air coupled sound. It was confirmed that discovery and the identification of a buried thing were possible using the OFR method （optimum frequency range method）. However, in this method, only the amplitude of the vibration speed spectrum is used and did not use the phase information. Therefore a new imaging method is proposed that used the phase information of the vibration speed spectrum. From the experimental results, the possibility of the outline extraction by using the phase difference between each scan point is confirmed. As a future task, the phase difference image will become clearer by changing the scan point density and long duration time of emitted wave.展开更多
基金Sponsored by the National Natural Science Foundation of China(Grant No.60073074).
文摘This paper presents Isotope, an efficient, locality aware, fault-tolerant, and decentralized scheme for data location in distributed networks. This scheme is designed based on the mathematical model of decentralized location services and thus has provable correctness and performance. In Isotope, each node needs to only maintain linkage information with about O(log n) other nodes and any node can be reached within O(log n) routing hops. Compared with other related schemes, Isotope’s average locating path length is only half that of Chord, and its locating performance and locality-awareness are similar to that of Pastry and Tapestry. In addition, Isotope is more suitable for constantly changing networks because it needs to exchange only O(log n) O(log n) messages to update the routing information for nodes arrival, departure and failure.
文摘Buried object which exists at extremely shallow underground can be detected by using an acoustic vibration and a SLDV （scanning laser Doppler vibrometer）. Non-contact acoustic exploration can be realized by using air coupled sound. It was confirmed that discovery and the identification of a buried thing were possible using the OFR method （optimum frequency range method）. However, in this method, only the amplitude of the vibration speed spectrum is used and did not use the phase information. Therefore a new imaging method is proposed that used the phase information of the vibration speed spectrum. From the experimental results, the possibility of the outline extraction by using the phase difference between each scan point is confirmed. As a future task, the phase difference image will become clearer by changing the scan point density and long duration time of emitted wave.
