• Journal of Astronomy and Space Sciences
• /
• v.14 no.1
• /
• pp.94-108
• /
• 1997

The temperature of the upper thermosphere is generally varied with the solar activity, and largely with geomagnetic activity in the high latitude. The data analyzed in this study are acquired at two ground stations, Thule Air Base($76,5{deg} N, 68.4{deg} W, A = 86{deg}$) and $S{psi}ndre Str{psi}mfjord (67.0{deg} N, 50.9{deg} W, A = 74{deg}$), Greenland. Both stations are located in the high latitude not only geographically but also geomagnetically. The terrestrial night glow at 6300 ${angs}$ from atomic oxygen has been observed from the two ground-based Fabry-Perot interferometers, during periods of 1986~1991 in Thule Air Base and 1986~1994 in $S{psi}ndre Str{psi}mfjord$. Some features noted in this study are as follows: (1) The correlation between the solar activity and the measured thermospheric temperature is highest in the case of $3{leq}Kp{leq}4$ in Thule, and increases with the geomagnetic activity in $S{psi}ndre Str{psi}mfjord$. (2) The measured temperatures at Thule is generally higher than those at $S{psi}ndre Str{psi}mfjord$, but the latter shows steeper slope with the solar activity. (3) The harmonic analysis shows that the diurnal variation(24hrs) is the main feature of the daily temperature variation with a temperature peak at about 13-14 LT (LT=UT-4). However, the semi-diurnal variation is evident during the period of weak solar activity. (4) Generally the predicted temperatures from both MSIS86 and VSH models are lower than the measured temperature, and this discrepancy grows as the solar activity increases. Therefore, we urge modelers to develope a new thermospheric model utilizing broader sets of measurements, especially for high solar activity.

• Phonetics and Speech Sciences
• /
• v.16 no.2
• /
• pp.49-58
• /
• 2024

This study aimed to compare the acoustic measurements of speech samples recorded from individuals with normal voices using various devices: the Computerized Speech Lab (CSL), a unidirectional wired pin-microphone (WIRED) suitable for smartphones, the built-in omnidirectional microphone (SMART) of smartphones, and Bluetooth-connected wireless earphones, specifically the Galaxy Buds2 Pro (WIRELESS). This study included 40 normal adults (12 males and 28 females) who had not visited an otolaryngologist for respiratory diseases within the past three months. Participants performed sustained vowel /a/ phonation for four seconds and reading tasks with sentences ("Walk") and paragraphs ("Autumn") in a sound-treated booth. Recordings were simultaneously conducted using the four different devices and synchronized based on the CSL-recorded samples for analysis using the MDVP, ADSV, and VOXplot programs. Compared with CSL, the Cepstral Spectral Index of Dysphonia (CSID_V, CSID_S) and Acoustic Voice Quality Index (AVQI) values were lower in the WIRED and higher in the SMART. The opposite trend was observed for the L/H spectral ratios (SR_V and SR_S), and the WIRELESS demonstrated task-specific discrepancies. Furthermore, both the fundamental frequency (F0) and the cepstral peak prominence of the vowel samples (CPP_V) had intraclass correlation coefficient (ICC) values above 0.9, indicating high reliability. These variables, F0 and CPP_V were considered highly reliable for voice recordings across different microphone types. However, caution should be exercised when analyzing and interpreting variables such as the SR, CSID, and AVQI, which may be influenced by the type of microphone used.