著者

武捨 貴昭

出版者

海洋音響学会

雑誌

海洋音響学会誌 (ISSN:09165835)

巻号頁・発行日

vol.30, no.4, pp.299-304, 2003-10

著者

倉本 和興 老松 建成 桑原 信也 山口 静馬

出版者

特定非営利活動法人 海洋音響学会

雑誌

海洋音響学会誌 (ISSN:09165835)

巻号頁・発行日

vol.31, no.2, pp.81-85, 2004-04-01 (Released:2011-03-02)

参考文献数

9

---

In order to examine the effects of air bubble in the ear canal for underwater hearing, detailed measurement of minimum audible field (MAF) in audio frequency (50Hz-8kHz) and comparison of loudness were carried out at two conditions as below, 1) the air bubble remains in the ear canal and 2) the ear canal is filled with water. As the result, in the high frequency region over about 300 Hz, it is highly sensitive to hearing in the case that the air bubble remained in the ear canal. In the low frequency region under 300 Hz, it becomes more sensitive in the case that the ear canal was filled with the water by removing the air bubble.The reverse phenomenon of “hearing” at about 300 Hz is explained by difference between frequency characteristics of the occlusion effect (air conduction) and the effect in which the ear canal was filled with the water (bone conduction).

著者

澤 隆雄 青木 太郎 大澤 弘敬 井上 朝哉 田原 順一郎 伊藤 和彰 吉田 弘 石橋 正二郎 渡辺 佳孝

出版者

特定非営利活動法人 海洋音響学会

雑誌

海洋音響学会誌 (ISSN:09165835)

巻号頁・発行日

vol.36, no.1, pp.26-32, 2009 (Released:2009-08-18)

参考文献数

7

被引用文献数

1

---

The Japan Agency for Marine-Earth Science and Technology is developing an automatic bottom inspection and sampling mobile (ABISMO), which is a full-depth rating ROV (Remotely Operated Vehicle) for reaching to the deepest sea bottom, observing it with a camera and sampling the bottom layer. ABISMO consists of a launcher and a vehicle. The launcher is a kind of depressor with many observation devices, and the vehicle is an underwater crawler to move on the sea bottom and inspect it. The mother ship can determine the vehicle's position directly with the ultra-deepwater transponder. The transponder is small and lightweight, with a release system, and it operates at about a 14-kHz frequency. The frequency is higher than that of a conventional full-depth transponder, and it features greater navigation accuracy in shallow water, where many ROV do most of their work. These advantages are emphasized when the transponder is loaded onto an ultra-deepwater vehicle, which needs to be small and lightweight.

著者

柴﨑 忠幸

出版者

海洋音響学会

雑誌

海洋音響学会誌 = The journal of the Marine Acoustics Society of Japan (ISSN:09165835)

巻号頁・発行日

vol.44, no.3, pp.152-156, 2017-07

著者

新家 富雄

出版者

海洋音響学会

雑誌

海洋音響学会誌 (ISSN:09165835)

巻号頁・発行日

vol.31, no.4, pp.251-262, 2004-10

被引用文献数

1

著者

新家 富雄 江本 博俊 今津 安成

出版者

海洋音響学会

雑誌

海洋音響学会誌 (ISSN:09165835)

巻号頁・発行日

vol.37, no.2, pp.117-121, 2010-04

著者

山口 静馬 倉本 和興 桑原 信也 老松 建成

出版者

特定非営利活動法人 海洋音響学会

雑誌

海洋音響学会誌 (ISSN:09165835)

巻号頁・発行日

vol.18, no.4, pp.209-212, 1991 (Released:2011-03-02)

参考文献数

9

著者

小浜 俊一 江川 護

出版者

The Marine Acoustics Society of Japan

雑誌

海洋音響学会誌 (ISSN:09165835)

巻号頁・発行日

vol.20, no.4, pp.228-233, 1993

---

In the case of the passive sonar, the LOFAR-Grams of received signals using frequency analysis and variable density visualization technique is widely used for target signal detection. The auto-spectrum analysis method is a signal processing means for the LOFAR-Grams.<BR>As the means to improve the ratio of signal to noise levels (S/N), there is a process of averaging (cumulative processing) analyzed signals used in the LOFAR-Grams.<BR>The discrimination signals smoothed cumulatively in the auto-spectrum method are apt to be difficult due to the nature of noise components, and this auto-spectrum method is not used in this case.<BR>We proposed a new method here, and analyzed experimentally several types of signals of the passive sonar utilizing this method for the LOFAR-Grams.<BR>The results showed that the process gain by cumulative method was obtained in accordance with calculation, and the delay type cross-spectrum method gave processing gain 3 dB higher than the auto-spectrum method.<BR>It was considered that this technique was to be applied extensively to the passive sonar in the future.