- 著者
- Tatsuhiro Tanaka Makoto Otani
- 出版者
- ACOUSTICAL SOCIETY OF JAPAN
- 雑誌
- Acoustical Science and Technology (ISSN:13463969)
- 巻号頁・発行日
- vol.44, no.4, pp.317-327, 2023-07-01 (Released:2023-07-01)
- 参考文献数
- 29
Isotropy is a fundamental property of a diffuse sound field. Although several studies have proposed an isotropy indicator to quantify the extent of the isotropy of a sound field, what is not yet very clear is how to interpret the quantified isotropy using these indicators. This study aims to contribute to the understanding of the isotropy by (i) modifying an existing isotropy indicator based on the spherical harmonic expansion and (ii) presenting isotropic sound field model composed of a finite number of plane waves. Theoretical and numerical investigations show that a limited-degree isotropy can be established by using the isotropy indicator and the isotropic sound field model.
- 著者
- Keiji MURAMATSU Yoshihisa FUJINO Tatsuhiko KUBO Makoto OTANI Shinya MATSUDA
- 出版者
- National Institute of Occupational Safety and Health
- 雑誌
- Industrial Health (ISSN:00198366)
- 巻号頁・発行日
- vol.57, no.1, pp.79-83, 2019 (Released:2019-02-05)
- 参考文献数
- 17
- 被引用文献数
- 8
This study used health insurance claims data to examine the relationship between the length of sick leave and treatment administered to employees who received middle- to long-term accident and sickness benefits for ≥91 d due to mood disorders, anxiety, and dissociative, stress-related, somatoform and other nonpsychotic mental disorders. Employees who received psychotherapy had significantly shorter leaves of absence over one year compared to those that did not. Treatment with psychotropic drugs was significantly higher among those on leave for ≤365 d than those on leave for ≥366 d. Age, sex and hospital treatment were not significantly associated with length of sick leave. These results suggest that professional psychological treatment is associated with length of sick leave.
- 著者
- Makoto OTANI Tatsuya HIRAHARA
- 出版者
- The Institute of Electronics, Information and Communication Engineers
- 雑誌
- IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences (ISSN:09168508)
- 巻号頁・発行日
- vol.E94-A, no.9, pp.1779-1785, 2011-09-01
A non-audible murmur (NAM), a very weak whisper sound produced without vocal fold vibration, has been researched in the development of a silent-speech communication tool for functional speech disorders as well as human-to-human/machine interfaces with inaudible voice input. The NAM can be detected using a specially designed microphone, called a NAM microphone, attached to the neck. However, the detected NAM signal has a low signal-to-noise ratio and severely suppressed high-frequency component. To improve NAM clarity, the mechanism of a NAM production must be clarified. In this work, an air flow through a glottis in the vocal tract was numerically simulated using computational fluid dynamics and vocal tract shape models that are obtained by a magnetic resonance imaging (MRI) scan for whispered voice production with various strengths, i.e. strong, weak, and very weak. For a very weak whispering during the MRI scan, subjects were trained, just before the scanning, to produce the very weak whispered voice, or the NAM. The numerical results show that a weak vorticity flow occurs in the supraglottal region even during a very weak whisper production; such vorticity flow provide aeroacoustic sources for a very weak whispering, i.e. NAM, as in an ordinary whispering.