著者
秋田 剛 名取 通弘
出版者
一般社団法人 日本航空宇宙学会
雑誌
宇宙技術 (ISSN:13473832)
巻号頁・発行日
vol.5, pp.33-41, 2006 (Released:2006-11-02)
参考文献数
38
被引用文献数
1 1

A new sensitivity analysis method for membrane wrinkling is presented. The wrinkling phenomenon is modeled by the tension filed theory with a projection technique. In the technique, the total strain energy in wrinkled membranes is effectively decomposed into elastic energy and zero-strain energy parts using a projection matrix. The zero-strain energy part depends on only the zero-energy deformation caused by wrinkling, and is utilized for a quantifier of degree of membrane wrinkling at a material point. The wrinkle quantity of the discretized membrane element is obtained by the integral of the zero-strain energy over each element. The total wrinkle quantity of whole membrane is also obtained by the summation of the elemental wrinkle quantities. The sensitivity of the total wrinkle quantity is derived with respect to displacement vector and also design parameter. The latter is given by the semi-analytical differentiation method (SDM). The proposed sensitivity analysis method is applied to a shape design problem for wrinkle reduction of a square membrane to demonstrate its effectiveness.
著者
春名 純一 山中 寛男 宮下 和久 香河 清和 橘 一也 秋田 剛 木内 恵子
出版者
一般社団法人 日本集中治療医学会
雑誌
日本集中治療医学会雑誌 (ISSN:13407988)
巻号頁・発行日
vol.16, no.2, pp.175-180, 2009-04-01 (Released:2009-10-15)
参考文献数
14

【目的】病院における騒音は,以前から指摘されてきたにもかかわらず,十分な対策は立てられておらず,また現状評価もなされていない。そこで,最も騒音レベルが高い小児集中治療室(pediatric ICU, PICU)において,騒音の音響学的測定と分析を試みた。【方法】大阪府立母子保健総合医療センターPICUにおいて,連続7日間および24時間の5分間等価騒音レベル,ピークサウンドプレッシャーレベル,1/3オクターブバンド等価音圧レベルを測定した。【結果】連続7日間の同時刻の等価騒音レベルは平均約60 dBA,ピークサウンドプレッシャーレベルは平均約90 dBAで,他の報告と同じく高いレベルであった。1日の8時点における測定では,日内差はあまり見られなかった。1/3オクターブバンド等価音圧レベルは全周波数帯でほぼ同じレベルで,低周波領域の音圧レベルが高かった。【結論】PICU騒音はWHOの院内騒音基準を大きく超えるレベルにあり,患者および医療スタッフの健康被害をもたらす可能性がある。周波数分析からは低周波音の関与が示唆された。
著者
秋田 剛 平手 小太郎 安岡 正人
出版者
日本建築学会
雑誌
日本建築学会環境系論文集 (ISSN:13480685)
巻号頁・発行日
vol.68, no.567, pp.79-86, 2003-05-30 (Released:2017-01-27)
参考文献数
20
被引用文献数
2 1

Effects of attention on visual perception are investigated by means of analysis of visual evoked potentials that reflect visual information processing in brain. For the purpose, an experiment is carried out on two experimental conditions. The first condition requires subjects to watch visual stimuli that are presented to them repeatedly, and the second requires them to do auditory tasks while watching visual stimuli. Results of the experiment show that response quantity of visual information processing is diminished when auditory tasks that attract subject's attention to hearing are imposed on them, even if they see visual stimuli using their central vision.
著者
辻村 壮平 秋田 剛 小島 隆矢 佐野 奈緒子
出版者
日本建築学会
雑誌
日本建築学会環境系論文集 (ISSN:13480685)
巻号頁・発行日
vol.80, no.711, pp.397-405, 2015 (Released:2015-06-24)
参考文献数
23
被引用文献数
9

In order to investigate an influence of indoor sound environment in office on knowledge creative activity, subjective experiments were conducted in our study. In this experiments, subjective evaluations on “ease of meeting”, “quietness of sound environment” and “listening difficulty of speech” in two different types of group meetings (decision-making meeting and discussion to think of creative ideas) were measured under five types of sound environmental conditions (no-noise LAeq, 5min 38 dB, ambient noise (conversation noise) LAeq, 5min 40 dB, 45 dB, 50 dB, 60 dB) in a meeting room of the university. From the results, in regard to “quietness of sound environment”, we found that subjects start feeling noisy (not quiet) in sound environmental condition of ambient noise 50 dB, and that of 60 dB have an increased “listening difficulty of speech”. In the ambient noise 50 dB, “ease of meeting” was the highest evaluation for discussion to think of creative ideas among these experimental conditions. Furthermore, to investigate psychological factors related to ease of meeting, multiple regression analysis was performed using the data obtained from subjective experiments. These results of multiple regression analysis show that a quiet sound environment is not necessarily desirable in discussion to think of creative ideas. It was found that very quiet sound environment decrease the evaluation of “ease of meeting” in discussion to think of creative ideas. Thus, it was suggested that recommended indoor sound environmental condition to conduct discussion to think of creative ideas was ambient noise 50 dB.