The severity of obstructive sleep apnoea (OSA) is diagnosed with polysomnography (PSG), during which patients are monitored by over 20 physiological sensors overnight. These sensors often bother patients and may affect patients’ sleep and OSA. This study aimed to investigate a method for analyzing patient snore sounds to detect the severity of OSA. Using a microphone placed at the patient’s bedside, the snoring and breathing sounds of 22 participants were recorded while they simultaneously underwent PSG. We examined some features from the snoring and breathing sounds and examined the correlation between these features and the snore-specific apnoea-hypopnea index (ssAHI), defined as the number of apnoea and hypopnea events during the hour before a snore episode. Statistical analyses revealed that the ssAHI was positively correlated with the Mel frequency cepstral coefficients (MFCC) and volume information (VI). Based on clustering results, mild snore sound episodes and snore sound episodes from mild OSA patients were mainly classified into cluster 1. The results of clustering severe snore sound episodes and snore sound episodes from severe OSA patients were mainly classified into cluster 2. The features of snoring sounds that we identified have the potential to detect the severity of OSA.
The residual stress in InP layers grown by microchannel epitaxy (MCE) on Si substrates was calculated using the three-dimensional finite element method (FEM). In the calculation, stress is assumed to be produced by the difference in thermal expansion between InP and Si during the cooling stage after the growth. No formation or movement of dislocations, by which the stress is released, is assumed. The calculation shows that the island structures of MCE layers are useful to reduce thermally induced stress. For example, stress in an MCE layer can be reduced to one-hundredth of that of a conventional uniform epitaxial layer. The calculation also shows that the stress at the MCE surface decreases rapidly with increasing the layer thickness. On the other hand, the change in stress is very small with varying the line-seed width or the thickness of the SiO2 mask. It is shown that the residual stress is further decreased when the MCE layer slips freely on the SiO2 mask.
SUMMARYThere have been many studies of auditory scene analysis in which an attempt was made to understand external events through acoustic signals. In particular, when the target is limited to music, there have been several studies aiming at automatic music scoring. In most previous studies, however, the procedure is constantly limited to local processing. Even if the procedure continues along the time axis, it is confined to the local neighborhood on the time axis, and only limited processing performance is realized. The purpose of this paper is to improve this aspect. A method is proposed which focuses on the hierarchical structure in the perception of the acoustic stream and extracts a single note string corresponding to each part from the music. In the proposed method, phrases are formed as an intermediate step in extracting the parts. Local clues are used in forming the phrases, and global clues are used in forming the parts. By using this approach, the parts are successfully extracted without problems such as explosion of the computational complexity. In a preliminary experiment, the parts were successfully extracted with a reproduction rate of approximately 80% and a fit rate of approximately 85%.
Operating Method of Train Longer than Platforms for the Purpose of IncreasingTransportation Capacity HANDA Ibuki, Student Member, SONE Satoru, Member (The University of Tokyo)Nowadays transportation capacity in urban area is insufficient and trains are heavily crowded. This paper proposes the train operation in which a part of a long train is off the platforms to increase transportation capacity without lengthening platforms and has examined the effect of such operation. Under the operation, serviceable cars for a certain passenger are limited. By taking advantage of individual guidance, however, every passenger can be led to a proper car which meets his OD(origin-destination). Ideal distribution of passengers to each car is determined by convex quadratic problem and optimal stopping position at each station is planned by hill-climbing method. It has been confirmed by the simulation for several models that the operation is highly effective to transportation capacity.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.