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Effect of Background Music for Attentive Concentration in Working
Sihun Park,Chanbeom Kwak,Woojae Han 한국청각언어재활학회 2020 Audiology and Speech Research Vol.16 No.3
Purpose: Recently, many young people have preferred to work in café than traditional library because the café is equipped with coffee, music, and cozy seats. When working in the café, whether listeners’ attentive concentration could be affected by a kind of the background music needs to be investigated as the purpose of the present study. We also aimed to confirm the attentive concentration of listeners might be caused by their music inclination. Methods: A total of ninety young adults was randomly assigned as five kinds of background music [e.g., rhythm and blues (R&B)/ballad, dance/rock, classic/jazz, fast beats, slow beats] and no music after responding to simple questions to ask their preference of music genre. While listening to the music, the subjects took an attentive concentration test, namely Frankfurter aufmerksamkeits-inventar (FAIR). The obtained data were analyzed by three subcategories of the FAIR test which consists of performance, quality, and continuity. Results: For the music genre, classic/jazz showed significantly higher continuity scores than R&B/ballad, fast beats, and no music, which means that classic/jazz music of the café could help the workers maintain the attention. In the subgroup who listened to preferred music genre, their performance scores (i.e., selective attention) was significantly higher than that of the participants who being exposed to non-preferred music. Conclusion: Current results supports that music genre and individual music inclination may partially affect listener’s ability of the attentive concentration when background music was presented in the café, although a further study to find certain possible causal factors with objective methods should be followed.
Design Consideration of Two Flat Transformers in a Low-Profile LLC Resonant Converter
Sihun Yang,Seiya Abe,Masahito Shoyama 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5
This paper presents the design consideration of a low-profile LLC resonant converter using two flat transformers. The trend toward high power density, high efficiency, and low profile in power supplies has exposed a number of limitations in the use of magnetic component structures. The LLC resonant converter can be operated at a high switching frequency with high efficiency because the switching loss is reduced by soft-switching. However, flat transformer loss causes problems at a high switching frequency. As a result, temperature of flat transformers becomes high. Therefore, it is necessary to reduce the transformer temperature by analyzing the loss. In this proposed converter, flat transformer is integrated into advanced power conversion application systems. Low-profile power module of profile of about 14㎜ is achieved. Temperature inside of transformer repressed to 61℃ and an overall efficiency of about 97.8% was obtained.
Analysis for Error Patterns of Consonant-Vowel Combinations in Hearing-Impaired Elderly
Sihun Park,Woojae Han 한국청각언어재활학회 2020 Audiology and Speech Research Vol.16 No.3
Purpose: Many previous studies related to speech recognition of hearing-impaired elderly have found that the elderly have difficulty in monosyllable recognition under noisy situations, but there is still lack of their specific information to perceive the monosyllables in terms of error pattern. The purpose of the present study was to measure and analyze the prominent errors of consonant (C)- vowel (V) combinations as a function of noise levels in the hearing-impaired elderly. Methods: A total of twenty older adults with sensorineural hearing loss participated. While randomly presenting 122 syllables which consisted of the Korean CV and VC combinations under quiet and two signalto- noise ratios (SNRs, +6 and +3 dB) conditions, the participants were asked to respond the syllables heard in a way of either discrimination or identification. Error rate (or percent incorrect) and error patterns of the syllables were analyzed in each condition. Results: Substitution error of the initial consonant showed the highest rate regardless of the background conditions. As the medial phoneme, the vowel errors were decreased as the level of noise increased. In the final consonant, additional error rate of /k/ was abruptly increased as SNR decreased. Furthermore, it was an interesting pattern that the initial consonants such as /s/, /l/, and /t*/ had a high substitution error rate when combined with /i/, /o/, and /ɛ/ vowels, respectively. Conclusion: Based on the current results, the hearing-impaired older adults seem to have their unique error patterns although there is individual difference. We expect that these results will be fundamental data to understand characteristics of speech perception in the older adults at the monosyllables level.
Jo, Sihun The Youngnam Mathematical Society 2018 East Asian mathematical journal Vol.34 No.3
We investigate the averaging value of a random sampling ${\zeta}(1/2+iX_t)$ of the Riemann zeta function on the critical line. Our result is that if $X_t$ is an increasing random sampling with Poisson distribution, then $${\mathbb{E}}{\zeta}(1/2+iX_t)=O({\sqrt{\;log\;t}}$$, for all sufficiently large t in ${\mathbb{R}}$.