| Co-Investigator(Kenkyū-buntansha) |
HASHIMOTO Taro HIMEJI INSTTTURE OF TECHNOLOGY, DEPARTMENT OF ELECTRICAL ENGINEERING AND COMPUTER SCIENCES, RESEARCH ASSISTANT, 工学研究科, 助手 (40285341)
YAMAUCHI Kenji HIMEJI INSTTTURE OF TECHNOLOGY, DEPARTMENT OF ELECTRICAL ENGINEERING AND COMPUTER SCIENCES, PROFESSOR, 工学研究科, 教授 (80047597)
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| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2002: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 2001: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2000: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Research Abstract |
An experimental study of human body detection was carried out. The human bodies which are buried under the debris when buildings are fall down due to earthquakes are not found easily by visual inspection. In this research project, the method of human body detection by measuring high- frequency electromagnetic wave reflection has been studied.
When microwaves illuminate the bebris, the total reflection includes the reflections from the human body under the debris. In this sense, the human body can be detected theoretically by inspecting the reflected waves, however, human body reflections are very small compared to total reflection, for example, -30 to -70dB. To get rid of this difficulty, we divide the total reflection into two components; time- valiant and time- invaliant signals. The time- valiant signal corresponds to human reflection which varies periodically according to the breath, and its period may be 2 to 4 seconds. The time-invariant components are generated by the debris surf
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ace, materials around the human body, etc. The time-invariant signal can be cancelled out by matching circuit. If the time-invariant components are perfectly cancelled, the receiver input is time-variant signal only, the human body reflection.
The experiments have been carried out by using a rectangular box made of wood panels, whose dimension of height, width, depth are 1.8m, 0.8m, 0.8m in length. In this box, a model of debris, components of Japanese citizen houses such as woods, ceramic boards, etc. are stuffed randomly. The measurement frequency is 10GHz, output power of the generator 10dBm, and the transmission and receiving antennas are 1.9m from the box. A testee (age: 23, gender: male) who took breath in normal way stood 0.9m apart behind the debris box.
The receiving power was around - 30 to -40dBm before controlling the cancel circuit. By adjusting the matching stubs, canceling the time- invariant signal under - 90dBm, the time- variant components with the period of 2 to 4 seconds are disclosed in the receiver screen. The amplitude of the signal was around 3 to 10dB. When the testee stopped the breath the signal did not fluctuate, which means the signal was reflection from the testee behind the debris box. Thicker the debris, smaller the human reflection and the detection becomes more difficult. At present, human bodies under the debris of 0.8m thick can be detected. Taking into account the actual situation of a disaster, thicker than 2m may be necessary at least. More elaborate signal processing and matching system will be required. Less
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