中川 誠司

The traditional concept for production of daily artificial sounds has changed from finding a solution to unwanted noise to designing a particular sound. Uncomfortable level (UCL) is an important factor to be considered when designing sounds such as alarms and notification signals. Although UCLs have been widely investigated using psychoacoustic methods, brain activity associated with them has been not yet clear. Here, we measured magnetoencephalographic (MEG) responses when participants passively listened to a series of pure tones that varied in frequency and intensity. A psychoacoustic experiment was also performed on the same participants to obtain their subjective UCLs. Our results indicated that the amplitude and latency of the evoked auditory responses increased/decreased logarithmically as a function of increasing stimulus intensity level and the subjective UCL was appeared in the relaxation part of the change rate of auditory evoked responses. The relationship between the neurophysiological signals as indexed by the auditory-evoked and spontaneous responses and subjective UCL was captured and utilized to infer a model to estimate the UCL objectively.

In this study, as a part of comprehensive approach to develop an interface for tactile information delivery, we aimed at capturing the relationship between neuronal and perceptual sensitivity characteristics of in human hand as indexed by neuromagnetic and psychometric responses. Airpuff stimuli were presented to multiple locations on the ventral side of subjects' palm, which somatosensory evoked responses were observed. As a result, it was observed that the latency and amplitude of the evoked responses in the primary somatosensory area (SI) was not related to the location on the palm. Although mechanoreceptors in the palm area distributed densely at both the center of the palm and the proximal part of the proximal phalanges, no effects on location were found by the amplitude of the evoked responses at SI area. These results suggested that amplitude of the evoked responses at SI did not depend on the distribution of the mechanoreceptors. © 2013 Springer-Verlag Berlin Heidelberg.

Bone-conducted ultrasound (BCU) is perceived even by the profoundly sensorineural deaf. A novel hearing aid using the perception of amplitude-modulated BCU (BCU hearing aid: BCUHA) has been developed. However, there is room for improvement particularly in terms of sound quality. BCU speech is accompanied by a strong high-pitched tone and contain some distortion. In this study, the sound quality of BCU speech with several types of amplitude modulation [double-sideband with transmitted carrier (DSB-TC), double-sideband with suppressed carrier (DSB-SC), and transposed modulations] and air-conducted (AC) speech was quantitatively evaluated using semantic differential and factor analysis. The results showed that all the types of BCU speech had higher metallic and lower esthetic factor scores than AC speech. On the other hand, transposed speech was closer than the other types of BCU speech to AC speech generally; the transposed speech showed a higher powerfulness factor score than the other types of BCU speech and a higher esthetic factor score than DSB-SC speech. These results provide useful information for further development of the BCUHA. (c) 2013 The Japan Society of Applied Physics

Human listeners can perceive speech signals in a voice modulated ultrasonic carrier from a bone-conduction stimulator, even if the listeners are patients with sensorineural hearing loss. Considering this fact, we have been developing a bone-conducted ultrasonic hearing aid (BCUHA). The purpose of this study is to evaluate the ability of BCUHA to transmit Japanese distinctive features to the recipient. For this purpose, a series of mono-syllable intelligibility experiments was conducted. A series of sequential information transfer analyses (SINFA) were carried out to analyze what kind of articulatory features were well transmitted. Results of the SINFA showed that: in vowel perception, "openness' and "frontness' were well transmitted, while in consonant perception, Japanese "you-on' (palatalized sound) feature was well transmitted, however, transmission of other features like articulatory position or manner was limited. These results indicated that the BCUHA has sufficient frequency resolution to transmit vowel information, while some signals are masked by carrier sound. To improve this problem, further investigation and development is required. © 2013 Acoustical Society of America.

演奏家にとって，音のオンセットが同時であるか非同時であるかは，音楽的な表現に違いをもたらしてしまう非常に重要な要素である．したがって，演奏家は常に注意深くオンセットの同時性を判断している．そこで，本研究においては，このような演奏家としての同時性判断の経験が，知覚および生理反応に影響を及ぼしているのかどうかを観察した．まず，プロ演奏家，アマチュア演奏家および非演奏家を実験参加者として，同時生判断の精度を測定する行動実験を行った．次に，音のオンセットに起因して生じる聴性脳幹反応を測定した．その結果，演奏経験が長いほど同時性判断の精度が有意に高くなり，継続的に注意深く聞き続けることによって知覚精度が高まることが示唆された．また，聴性脳幹反応においても，プロ演奏家の方が，脳幹レベルにおける時間分解能が高まっている可能性があり，継続的で注意深い同時性判断は，生理反応にも影響を及ぼしている可能性が示された．

情報システム開発の超上流工程では，新しいサービスや業務プロセス（ビジネス要件）の検討と，それらを実現するためのシステム要件の開発とを並行して進める必要がある．本論文では，ユーザ企業と開発ベンダが協力の上，ステークホルダ間における合意形成を段階的に進めることによって，ビジネス要件とシステム要件の検討を並行して進めることを可能とする手法「協創プロセスによる段階的合意形成手法＝ Ex アプローチ」に関して，事例を通じて紹介し，これを導入する効果・利点について述べるとともに，今後の課題を明らかにする．

The traditional production concept for car engine sound has changed from finding a solution to unwanted noise, to designing a particular sound. Although many studies have investigated the development of comfortable car-engine sounds, the psychoacoustic effects of time-varying rate for accelerating engine sounds remain unclear. Thus, we investigated the effects of increasing the frequency of interior car noise on auditory impressions, using psychological and neurophysiological methods. We carried out two investigations. First, we examined the relationship between the impression of 'sportiness' from the dynamic characteristics of the engine sound and brain magnetic fields. Complex harmonic tones simulating acceleration noise were used as stimuli, and subjective evaluations were examined using the semantic differential method. Neuronal activity in the auditory cortex was measured using magnetoencephalography (MEG). Second, we examined the relationship between subjective preference and brain magnetic fields for the simulated interior noise of an accelerating car. Subjective evaluations were examined using a paired-comparison method. The MEG alpha-wave range (8-13Hz) was measured and analyzed using the autocorrelation function. Neuronal activity was longer following stimulation by a preferred sound. Our results indicated that the particular characteristics of engine sounds have a significant effect on subjective impressions and neuronal activity in the auditory cortex.

4 歳、男児。顔面神経麻痺により発見した横紋筋肉腫の 1 例を経験したので報告した。画像検査にて上咽頭右側から、中耳、頭蓋底に腫瘤性病変を認めた。上咽頭より生検を施行し、横紋筋肉腫の診断を得た。小児の顔面神経麻痺に遭遇した際は、中耳炎性だけでなく、頭頸部腫瘤による可能性も考えて診察することが重要であると考えられた。

Accurate estimation of CO2 saturation in a saline aquifer is essential for the monitoring of supercritical CO2 injected for geological sequestration. Because of strong contrasts in density and elastic properties between brine and CO2 at reservoir conditions, seismic methods are among the most commonly employed techniques for this purpose. However the relationship between seismic (P-wave) velocity and CO2 saturation is not unique because the velocity depends on both wave frequency and the CO2 distribution in rock. In the laboratory, we conducted measurements of seismic properties of sandstones during supercritical CO2 injection. Seismic responses of small sandstone cores were measured at frequencies near 1 kHz, using a modified resonant bar technique (Split Hopkinson Resonant Bar method). Concurrently, saturation and distribution of supercritical CO2 in the rock cores were determined via x-ray CT scans. Changes in the determined velocities generally agreed with the Gassmann model. However, both the velocity and attenuation of the extension wave (Young's modulus or bar' wave) for the same CO2 saturation exhibited differences between the CO2 injection test and the subsequent brine re-injection test, which was consistent with the differences in the CO2 distribution within the cores. Also, a comparison to ultrasonic velocity measurements on a bedded reservoir rock sample revealed that both compressional and shear velocities (and moduli) were strongly dispersive when the rock was saturated with brine. Further, large decreases in the velocities of saturated samples indicated strong sensitivity of the rock's frame stiffness to pore fluid.

Studies on the development of bone-conducted ultrasonic hearing aids (BCUHAs) have demonstrated the need for a flexibly configurable BCUHA. In a previous report, we constructed a personal-computer-based multi-channel BCUHA system consisting of a soundboard and signal control software and verified the real-time performance of the constructed system. In this study, we extended the BCUHA system to the real-time control of binaural parameters to realize sound source localization in the proper direction. Here, we describe the technical solution for implementing the function of real-time correction of binaural parameters and discuss further problems that need to be resolved for more effective control of binaural parameters. © 2013 ICIC International.

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The traditional concept for production of artificial sounds that are common in daily life has changed from finding a solution to unwanted noise to designing a particular sound. Uncomfortable level (UCL) is an important factor to be considered when designing sounds such as alarms and notification signals. Although UCLs have been widely investigated using psychoacoustic methods, brain activity associated with them is not yet clear. Here, we measured magnetoencephalographic (MEG) [1] responses when participants passively listened to a series of pure tones that varied in frequency and intensity. A psychoacoustic experiment was also performed on the same participants to obtain their subjective UCLs. Our results indicated that the amplitude and latency of the evoked auditory responses increased/decreased logarithmically as a function of increasing stimulus intensity level and the subjective UCL was appeared in the relaxation part of the change rate of auditory evoked responses. The relationship between the neurophysiological signals as indexed by the auditory-evoked and spontaneous responses and subjective UCL was captured and utilized to infer a model to estimate the UCL objectively.

Auditory evoked magnetic field (AEF) is gradually attenuated as the number of presentation of auditory stimuli increases. The attenuation of AEF is auditory habituation, and is prevented in the condition where a noise exists in the background. In this study, we investigated whether the background sound of pure tone prevent the auditory habituation to repeating stimuli. Subjects were 17 normal hearing individuals. Auditory stimuli were 1-kHz tone bursts set at 30 dB SL with durations of 100 ms and inter-stimulus intervals of 1.9-2.1 s. The background sounds were silent, 4-kHz pure tone presented set at 5 and 20 dB SL which were presented with 1-kHz tone bursts. N1m component of AEF induced by auditory stimuli was measured using 122-channel neuromagnetometer. As a result, N1m amplitudes induced by repeating auditory stimuli were gradually attenuated in the condition of silent background due to the auditory habituation. Meanwhile, the attenuation of N1m amplitude was small in the conditions of background sounds of 4-kHz pure tones at 5 and 20 dB SL, compared to the conditions of silent background. Moreover, the time course of N1m amplitudes was not different between the condition of background sound at 5 and 20 dB SL. These results suggested that the background sound of pure tone, independent of its intensity, drove the subject to unconsciously pay attention to repeating auditory stimuli without disturbing signal-to-noise ratio of them, or the neural process of the background pure tone continuously activated the auditory pathway and resulted in the prevention of auditory habituation.

A model of primary sensations and spatial sensations is proposed by Ando (2001). The model of the auditory-brain system includes the autocorrelation function (ACF), the interaural cross-correlation function (IACF) mechanisms. At present, environmental noises are evaluated by sound level such as equivalent continuous A-weighted sound pressure level (LAeq). However, we sometimes feel annoyed with sound with low sound level because of the quality. Sound quality can be characterized by factors obtained from ACF and IACF of sound. For example, pitch and pitch strength can be characterized by delay time and amplitude of the maximum peak of the ACF. Directional sensation can be characterized by delay time and amplitude of the maximum peak of the IACF. To verify the model, we investigated how ACF and IACF factors are coded in our human brain. The results indicated that delay time and amplitude of the maximum peak of the ACF and IACF are coded by the latency and strength of brain activity. © 2013 Acoustical Society of America.

Bone-conducted ultrasonic hearing aid (BCUHA) system is the unique device to provide the auditory sensation to profoundly hearing impaired persons without any surgical operations. To clarify effects of a long-term hearing training with this device, two deaf participants engaged the BCUHA training for more than 9 months. They were trained to use BCUHA through repetition of sentences read aloud, free conversation and singing, and then they participated in word recognition tests and monosyllable identification tests. Both participants showed that they could recognize words above chance using auditory sensation only provided by BCUHA if alternatives or context were presented to them. In addition, it was observed that monosyllable intelligibility score with both of auditory and visual cue had much increased with the days of training than the score with the auditory only cue and that with the visual only cue. The result suggests that the long-term training with BCUHA achieves efficient integration of the auditory and the visual cue of speech such as cochlear implant users showed in previous studies. © 2013 Acoustical Society of America.

Bone-conducted ultrasound (BCU) is perceived even by the profoundly sensorineural deaf. We have developed a novel hearing-aid using BCU perception (BCU hearing aid: BCUHA) for the profoundly deaf. In the BCUHA, ultrasonic sinusoids of about 30 kHz are amplitude-modulated by speech and presented to the mastoid. Generally, two sounds are perceived: one is a high-pitched tone due to the ultrasonic carrier, with a pitch corresponding to a 8-16 kHz air-conducted (AC) sinusoid, and the other is the envelope of the modulated signal. As a method of amplitude modulation (AM), double-sideband with transmitted carrier (DSB-TC) modulation had been used, however, the DSB-TC modulation is accompanied by a strong high-pitched tone. In this study, two new AM methods, double-sideband with suppressed carrier (DSB-SC) and transposed modulations, that can be expected to reduce the high-pitched tone were newly employed in the BCUHA, and their resulting articulations, intelligibilities and sound qualities were evaluated. The results showed that DSB-TC and transposed modulation had higher articulation and/or intelligibility scores than DSB-SC modulation. Further, in terms of sound quality, the transposed speech was closer than other types of BCU speech to AC speech. These results provide useful information for further development of the BCUHA. © 2013 Acoustical Society of America.

Tympanic membrane (TM) vibration under bone-conducted ultrasonic (BCU) stimulation was measured in four living human subjects using a laser Doppler vibrometer (LDV) to investigate the contributions of nonlinear distortions in the osseotympanic effects and/or the inertial effects of the middle-ear ossicles to ultrasonic perception in bone conduction. A signal processing algorithm to increase the signal-to-noise ratios of measured LDV signals by removing only optical spike noise components from the wave signals was presented in this study. Evidence of nonlinear distortions, especially the generation of audible subharmonics in the outer and middle ear, was then examined. We did not find any audible signals corresponding to the subjective pitch of a BCU tone in the TM vibrations. This suggests that nonlinear distortions in the osseotympanic and inertial effects do not contribute to BCU perception. Specific properties of perception may be related to mechanisms in the cochlea or afferent neural pathway. With this consideration, we discuss the possibility that the pitch perception of BCU does not relate to tonotopical motion of the basilar membrane corresponding to the subjective pitch, given that TM vibration can reflect the motion of cochlear fluid and hence the motion of the basilar membrane.

The notion that sound is a normal part of product operation is widespread in society. As a result, much attention has been directed at designing various sounds that are generally treated as noise. Car drivers detect variations in sound characteristics between different buttons, such as the pitch, tone color, loudness and duration of time-varying sounds, and these can affect the desirability of both a car and its audio system. In this study, we focused on the sound design of time-varying transient signals and evaluated this design using 11 different button sounds. We examined the subjective evaluations of the sounds by the subjects using the semantic differential method and neuronal activity in their auditory cortices evoked by these stimuli using magnetoencephalography. We found that button sound characteristics significantly affect subjective impressions and neuronal activity in the auditory cortex.

We present analyses to determine the fundamental parameters of the Galaxy based on VLBI astrometry of 52 Galactic maser sources obtained with VERA, VLBA, and EVN. We model the Galaxy's structure with a set of parameters, including the Galaxy center distance R-0, the angular rotation velocity at the LSR Omega(0), the mean peculiar motion of the sources with respect to Galactic rotation (U-src, V-src, W-src.), the rotation-curve shape index, and the V component of the Solar peculiar motions, V-circle dot. Based on a Markov chain Monte-Carlo method, we find that the Galaxy center distance is constrained at a 5% level to be R-0 = 8.05 +/- 0.45 kpc, where the error bar includes both statistical and systematic errors. We also find that the two components of the source peculiar motion U-src, and W-src are fairly small compared to the Galactic rotation velocity, being U-src = 1.0 +/- 1.5 km s(-1) and W-src = 1.4 +/- 1.2 km s(-1). Also, the rotation curve shape is found to be basically flat between Galacto-centric radii of 4 and 13 kpc. On the other hand, we find a linear relation between V-src and V-circle dot as V-src = V-circle dot - 19 (+/- 2) km s(-1), suggesting that the value of V-src is fully dependent on the adopted value of V-circle dot. Regarding the rotation speed in the vicinity of the Sun, we also find a strong correlation between Omega(0) and V-circle dot. We find that the angular velocity of the Sun, Omega(circle dot), which is defined as Omega(circle dot) Omega(0) + V-circle dot/R-0, can be well constrained with the best estimate of Omega(circle dot) = 31.09 +/- 0.78 km s(-1) kpc(-1). This corresponds to Theta(0) = 238 +/- 14 km s(-1) if one adopts the above value of R-0 and recent determination of V-circle dot similar to 12 km s(-1).