Toshifumi Kosaka

Body Sensation of Low Frequency Noise of Ordinary Persons and Profoundly Deaf Persons

Comparison of the thresholds of body sensation of profoundly deaf subjects and those of normal hearing, when exposed to intense low frequency noise, showed similar trends. Since the deaf subjects were judged to have normal balance mechanisms, it was concluded that the semicircular canals are not sensitive to low frequency noise at its normal levels in the environment.

Physiological effects of low frequency noise

In Japan there are two sorts oflowfrequency noiseproblems. One is that windows, doors and window frames are vibrated by infrasound or low frequency noise (LFN) and they emit rattling noises. The other is that lowfrequency noise is heard orfelt directly bypeople and they suffer irritation, headaches and sleeplessness. In this report physiological effects including galvanic skin response, respiration and heart rate etc. are studied.

Reduction of Micro-Pressure Wave by Active Control of Propagating Compression Wave in High Speed Train Tunnel

For the improvement of the sound environment around a portal of a high speed train tunnel, model experiments for the reduction of MPW (Micro-Pressure Wave) have been studied. In order to reduce the level of MPW, a control wave, that is a positive pressure, is generated at a side-branch in a model tunnel and is superposed on the incident wave front of a compression wave propagating through the tunnel. The method of active reduction of MPW and experimental equipment are shown. Characteristics of the wave forms of the compression wave and the control wave with suitably designed servo actuators were examined. The experimental results of the reduced level of MPW agreed well with numerical calculation results.

Construction and analysis of a data-base of low frequency noise problems

A considerable quantity of data on low frequency noise problems has been collected and published recentl y in journals. By analyzing these data. factors involved in the causes of problems may be clar ified. Some data were measured by the present authors and other dat a were collected from the Proceedin gs of Meetings of the Acoustical Society ofJapan, the Proceedings of Meetings of the INCE of Japan , the Journal of the INCE of Japan and some local government reports.

Active Attenuation of Low Frequency Noise Radiated from Tunnel Exit of High Speed Train

A pressure wave occurs at the instant when a high speed train enters into a long tunnel. The wave propagates downstream to the tunnel exit and low frequency noise is radiated from the exit to outer space. The low frequency noise causes a lot of problems1 to the residents living near the exit and has a close relation with the pressure gradient of the pressure wave. To attenuate the low frequency noise, an active cancellation system rather than a passive one is developed. This research uses a model tunnel to examine the characteristic of the pressure wave and investigates the possibility to reduce the low frequency noise by reducing the pressure wave gradient with active cancellation.

Promoting of Human Resources for Embedded Systems Development by Meister and Student Engineering Educator Accreditation System

工学教育(J.of JSEE), 61–1(2013) 1.はじめに 組み込みシステムは家電・OA・産業・通信の各機器 の高機能化・省力化を支え,ユビキタス社会を実現す る核となる技術である.しかし人の生活を便利にする はずの組み込みシステムがしばしば不具合を起こし, 大量リコール等社会問題化することがある.経済産業 省の調査では,組み込みシステム開発技術者(以下, 組み込み系技術者)の著しい不足が,不具合の多発に つながっていることが報告されている.産業界に必 要とされる人材の供給は高等教育機関にとって使命で あるが,複合融合分野である組み込みシステム開発を 専門に教育する学科等は,我が国にはほとんどない. 東京高専では,「組み込みシステム開発マイスター の育成教育」プロジェクトが,平成20年度に文部科学 省「質の高い大学教育推進プログラム(教育GP)に採 択され,事業補助期間終了後も継続実施している. この取組は従来の学科構成のまま,基礎学力を有しか つ「必要な力を持った組み込み系技術者」を育成する ものである.これまで単に優秀な成績で卒業させてい た学習意欲の高い学生をさらに伸ばす試み(伸びこぼ し対策)でもある.組み込みシステム開発の学習を修 めた学生には,インセンティブとして「組み込みシス テム開発マイスター」として認定を行っている. 学生同士で教え合う環境を用意するのも本取組の特 徴である.組み込みシステム開発は複合融合分野であ るため,所属学科以外の分野の知識が必要になる.そ こで講義そのものの他,講義終了後の演習やPBLプロ ジェクトにおいて,学生が自分の得意分野を他の学生 に指導したりアドバイスを行う.教える側として活躍 した学生には,教育能力を認め「学生教育士」として 認定する.学生教育士認定制度により,技術力だけで 2012 年9月7日受付 ※1東京工業高等専門学校 マイスター及び学生教育士制度による 組み込みシステム開発人材育成

Active control of impulsive low frequency noise emitted from tunnel exit of high speed train

INTRODUCTION When a high speed train enters into a long tunnel with slab tracks, impulsive low frequency noise(Impulsive LFN) is emitted from the tunnel exit. The impulsive LFN shakes windows and surprises inhabitants around the tunnel exit. As the high speed train (i.e. the Shinkansen in Japan) runs through many mountain areas, there are many long tunnels and environmental problems occur around the Shinkansen. Reduction of the impulsive LFN is an important problem for high speed running. This report describes mainly two studies. The first study describes the pressure distribution around the high speed train and the reduction effects on the traveling pressure wave by attaching some hoods at the tunnel entrance. Experiments were done with a small train model and a model train launcher. The latter study tries to reduce the impulsive LFN by active control with a negative pressure wave or a positive pressure wave in a small tunnel model.

Low‐frequeney noise problems and psychological and physiological influences of low‐frequency noise

In Japan infrasound or low‐frequency noises are emitted from highway bridges, large compressors, boilers, and diesel engines etc. Windows or doors of wooden houses are vibrated by infrasound and emit rattling noises. Low‐frequency noises are sometimes heard directly and annoy people. These complaints and low‐frequency noises were investigated. Psychological and physiological influences on university students and low‐frequency noise sufferers were investigated in a laboratory. University students were not influenced as much by low‐frequency noise. The results clearly indicated that the heart and respiration rates of several low‐frequency noise sufferers increased. Many low‐frequency noise sufferers were influenced psychologically or physiologically.