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Kenichiro NAGAYOSHI Kazuhiro SAKAI Kazuhisa MITSUDA Noriko Y. YAMASAKI Yoh TAKEI Keisuke MAEHATA Naoko IYOMOTO Shohei EZAKI Akira TAKANO Makoto MAEDA Toru HARA
Three-dimensionally assembled TES X-ray microcalorimeter arrays may be utilized for three purposes: (1) to obtain wide X-ray energy coverage of TES microcalorimeters, (2) to distinguish charged particle events from X-ray events, (3) to reconstruct Compton-scattering geometry for hard X-ray Compton cameras. We have designed and fabricated three-dimensionally assembled array of the minimum format i.e. $2 imes 2 imes 2$ array in order to obtain a good energy resolution in a wide energy range of 0.5--20,keV and a high maximum counting rate of 2000,cps for energy dispersive X-ray spectrometer (EDS) system for a transmission electron microscope (TEM). Although we could not obtain required energy resolution because of a problem in the refrigerator system, we confirmed the operation of the three-dimensional array.
Hiraku OKADA Akira TAKANO Kenichi MASE
One of the most promising applications of a mobile ad hoc network is a vehicular ad hoc network (VANET). Each vehicle is aware of its position information by GPS or other methods, so position-based routing is a useful approach in VANET. The position-based routing protocol can be classified roughly into a next-hop forwarding method and a directed flooding method. We evaluate performance of both methods by analytic approach and compare them in this paper. From the evaluation results, we conclude that it is effective for the position-based routing to choose either the next-hop forwarding method or the directed flooding method according to the environment. Then we propose the hybrid transmission method which can select one of them according to the environment, and clarify that the proposed method can keep the packet delivery ratio at a high level and reduce the delay time.