• Journal of Pharmacopuncture
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• v.22 no.3
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• pp.166-170
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• 2019

Objectives: Attentional and memory functions are important aspects of neural plasticity that, theoretically, should be amenable to pharmacopuncture treatments. A previous study from our laboratory suggested that quantitative electroencephalographic (qEEG) measurements of theta/beta ratio (TBR), an index of attentional control, may be indicative of academic performance in a first-semester medical school course. The present study expands our prior report by extracting and analyzing data on frontal theta and beta asymmetries. We test the hypothesis that the amount of frontal theta and beta asymmetries (fTA, fBA), are correlated with TBR and academic performance, thereby providing novel targets for pharmacopuncture treatments to improve cognitive performance. Methods: Ten healthy male volunteers were subjected to 5-10 min of qEEG measurements under eyes-closed conditions. The qEEG measurements were performed 3 days before each of first two block examinations in anatomy-physiology, separated by five weeks. Amplitudes of the theta and beta waveforms, expressed in ${\mu}V$, were used to compute TBR, fTA and fBA. Significance of changes in theta and beta EEG wave amplitude was assessed by ANOVA with post-hoc t-testing. Correlations between TBR, fTA, fBA and the raw examination scores were evaluated by Pearson's product-moment coefficients and linear regression analysis. Results: fTA and fBA were found to be negatively correlated with TBR (P<0.03, P<0.05, respectively) and were positively correlated with the second examination score (P<0.03, P=0.1, respectively). Conclusion: Smaller fTA and fBA were associated with lower academic performance in the second of two first-semester medical school anatomy-physiology block examination. Future studies should determine whether these qEEG metrics are useful for monitoring changes associated with the brain's cognitive adaptations to academic challenges, for predicting academic performance and for targeting phamacopuncture treatments to improve cognitive performance.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.18 no.6
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• pp.133-145
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• 2023

This paper examines whether investors have adapted to the venture capital(VC) investment style. VC firms invest in privately held companies and generate returns by selling them after the lock-up period expires. We analyze the impact on stock prices before and after the lock-up period expiration, and compare the Cumulative Abnormal Return(CAR) between the past period(2015-2017) and the recent period(2020-2022) to investigate the effect of the second venture boom. The main findings are as follows. First, unlike in the past, stock price returns around the lock-up period expiration have been lower than the KOSDAQ index in recent years. Second, the impact on stock prices is significant for both 1-month and 12-month lock-up periods. Specifically, it is confirmed that stocks held by venture capital and professional investors with a 1-month lock-up period respond in advance to their information after the second venture boom. Finally, we find that there is a difference in CAR depending on whether or not the company received VC investment after the second venture boom. Based on our findings, we suggest that VC firms need to revise their exit strategies to improve performance. This includes finding ways to reduce information asymmetry and fees, as well as developing strategies to mitigate market volatility. Additionally, the current lock-up period for VCs should be reconsidered as it may increase the risk of stock price decline. We recommend that the government revise the scope and duration of lock-up periods to protect investors after IPO.

• The Korean Journal of Nuclear Medicine
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• v.33 no.1
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• pp.28-39
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• 1999

Purpose: We investigated the difference of glucose metabolism of medial and lateral temporal lobes of patients with temporal lobe epilepsy (TLE) utilizing quantitative comparison of regional metabolic activities using asymmetric index. Materials and Methods: We studied 19 pathologically proven mesial TLE and 25 lateral TLE patients. Lateral TLE patients were either normal on magnetic resonance imaging (cryptogenic: n=14) or had structural lesions (lesional: n= 11). Asymmetric index (ASI) was calculated as [(ipsilateral-contralateral)/(ipsilateral+contralateral)]${\times}200$. Results: ASI of medial and lateral lobes of mesial TLE was decreased ($-16.4{\pm}8.3$ and $-12.1{\pm}5.5$, respectively). In cryptogenic lateral TLE, ASI of lateral temporal lobe was decreased ($-11.8{\pm}4.7$), whereas that of medial temporal lobe was not decreased ($-4.6{\pm}6.3$). ASI of medial lobe of lesional lateral TLE was $-7.3{\pm}9.1$, which was significantly different from that of mesial TLE (p<0.05). Patients with lesional lateral TLE had evident metabolic defects or decrease (ASI: $-22{\pm}10.5$) in lateral temporal lobe. While we could not find the difference of metabolic activity in lateral temporal lobes between cryptogenic lateral TLE and mesial TLE patients, the difference of metabolic activity was significant in medial temporal lobes which was revealed by ASI quantitation. Conclusion: Asymmetric decrease of metabolic activity in both medial and lateral temporal lobes indicates medial temporal epilepsy. Symmetry of metabolic activity in medial temporal lobe combined with asymmetry of that in lateral temporal lobe may give hints that the epileptogenic zone is lateral.

• Science of Emotion and Sensibility
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• v.22 no.3
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• pp.21-34
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• 2019

This study was an examination of the relevance and clinical significance of electroencephalographic (EEG) indexes (e.g., mental/physical stress and attention) and indexes of heart rate variability (HRV) with regard to cognitive function and physiological health conditions in elderly people. A device was used to record two-channel EEGs of the frontal lobe and a one-channel ECG simultaneously. Subjects were 76 people average aged 73. The significant findings are as follows: First, subjects whose intrinsic alpha rhythm had high amplitude, regardless of peak, showed higher resistance to mental stress and lower physical stress than did subjects with low-amplitutde intrinsic alpha rhythm. Second, HRV, SDNN, and RMSSD indexes showed strong positive correlations between the two groups of subjects regardless of the division of groups. Third, the alpha asymmetry of the left and right sides of the brain in subjects with low-amplitude intrinsic alpha rhythm was larger, and the delta/alpha ratio (reflecting physical stress) and theta/sensorimotor rhythm (SMR) ratio (showing the decline in attention) were bigger. Fourth, the subjects in whom intrinsic alpha rhythm peak occurred during slow rhythm had a higher theta/SMR ratio than did subjects whose peak occurred during fast rhythm, which was related to a steeper decline in attention. Therefore, the presence or absence of intrinsic alpha rhythm peak and amplitude on quantitative EEG may be an index reflecting the cognitive function and physiological health of elderly people.

• Journal of Distribution Science
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• v.18 no.2
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• pp.99-108
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• 2020

Purpose: This paper investigated the relationship between market competition and firm valuation error. Furthermore, Additional analyses were made according to the quality of financial reports and the listed market. Through the process we confirm to the impact of competition on the capital market. The purpose of this study is to analyze the impact of competition on valuation errors. The preceding studies did not provide a consistent results of the effects of competing functions on the capital market. One view is that the competition could mitigate the information asymmetry, and the other is that monopolistic lessens the manager's involvement in financial reporting. This study is intended to expand the prior study by analyzing the impact of competition on the capital market and on the valuation of investors. Research design, data, and methodology: The analysis was conducted on 12,031 samples over 11 years from 2008 to 2018 using data from market in Korea. Here the valuation error was measured by the research methodology of Rhodes-Kropf, Robinson and Viswanathan (2005), and competition measured by Herfindahl-Hirschman Index multiplied by (-1), and Concentration Ratio by (-1). Results: We confirm that the positive relationship between competition and the valuation error. In addition, we also found that the positive relation between competition and valuation error was in cases of low discretionary accruals and the KOSDAQ market. This means that the net function of competition does not mitigate valuation errors. Conclusions. This study has the following contributions when compared to prior research. First, the relevance between the level of competition and the valuation of the entity was confirmed. The study by Haw, Hu and Lee (2015) suggested that monopolistic industry of analysts' forecast is more accurate due to lower the variability in earnings. This study magnified it to confirm that monopolistic lessen information uncertainty in valuation. Second, the study on valuation errors was expanded. While the study on the effect of valuation errors on the capital market is generally relatively active, it is different that competition degree has analyzed the effect on valuation errors amid the lack of research on the effect on valuation errors.

• The Journal of Churna Manual Medicine for Spine and Nerves
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• v.7 no.2
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• pp.101-108
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• 2012

Objectives : To evaluate the clinical utility of Muscle Energy Techniques(MET) in Elector Spinae Muscle on subjects. Methods : We compared electrical activity between a before MET and a after MET in Elector Spinae Muscle on subjects in same group(n=26) in dynamic flexion-reextension state during five seconds. We analyzed amplitudes and areas of electrical activity and Asymmetry Index(AI) and Median Edge Frequency(MEF). Results : 1. After MET in Elector Spinae Muscle on subjects were lower electrical activity than before MET in Elector Spinae Muscle on subjects but it is not a pointless observation(p<0.05). 2. AI of the after MET in Elector Spinae Muscle on subjects significantly decreased compared with before MET in Elector Spinae Muscle on subjects(p<0.05). 3. MEF of the after MET in Elector Spinae Muscle on subjects decreased compared with before MET in Elector Spinae Muscle on subjects but it is not a pointless observation(p<0.05). Conclusions : According to above results, there is clinical effect MET on subjects.

• The Korean Journal of Applied Statistics
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• v.25 no.1
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• pp.29-43
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• 2012

Financial data such as stock index returns and exchange rates have the properties of heavy tail and asymmetry compared to normal distribution. When we estimate VaR using the GARCH model (with the conditional return distribution of normal) it shows the tendency of the lower estimation and clustering in the losses over the estimated VaR. In this paper, we argue that this problem can be resolved through the adaptation of the unbounded Johnson distribution as that of the condition return. We also compare this model with the GARCH with the conditional return distribution of normal and student-t. Using the losses exceed the ex-ante VaR, estimates, we check the validity of the GARCH models through the failure proportion test and the clustering test. We nd that the GARCH model with conditional return distribution of unbounded Johnson provides an appropriate estimation of the VaR and does not occur the clustering of violations.

• Journal of Korean Medicine Rehabilitation
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• v.23 no.1
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• pp.15-23
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• 2013

Objectives : To evaluate the clinical utility of MET in elector spinae muscle on low back pain patients. Methods : We compared electrical activity between a before MET and a after MET in elector spinae muscle on low back pain patients in same group(n=30) in dynamic flexion-reextension state during five seconds. We analyzed amplitudes and areas of electrical activity and asymmetry index(AI). Results : 1. After MET in elector spinae muscle on low back pain patients were significantly decreased in Visual Analogue Scale(VAS) than before MET in elector spinae muscle on low back pain patients(p<0.05). 2. After MET in elector spinae muscle on low back pain patients were lower electrical activity than before MET in elector spinae muscle on low back pain patients but it is not a pointless observation(p<0.05). 3. AI of the after MET in elector spinae muscle on low back pain patients significantly decreased compared with before MET in elector spinae muscle on low back pain patients(p<0.05). Conclusions : According to above results, there is clinical effect MET on low back pain patients.

• Phonetics and Speech Sciences
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• v.4 no.2
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• pp.61-70
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• 2012

The current study observes the durational interaction of tautosyllabic consonants and vowels in the word-initial position of English and Korean child-directed speech (CDS). The effect of phonological laryngeal contrasts in stops on the following vowel duration, and the effect of the intrinsic vowel duration on the release duration of preceding stops in addition to the acoustic realization of the contrastive segments are explored in different prosodic contexts - phrase-initial/medial, focal accented/non-focused - in a marked speech style of CDS. A trade-off relationship between Voice Onset Time (VOT), as consonant release duration, and voicing phonation time, as vowel duration, reported from adult-to-adult speech, and patterns of durational variability are investigated in CDS of two languages with different linguistic rhythms, under systematically controlled prosodic contexts. Speech data were collected from four native English mothers and four native Korean mothers who were talking to their one-word staged infants. In addition to the acoustic measurements, the transformed delta measure is employed as a variability index of individual tokens. Results confirm the durational correlation between prevocalic consonants and following vowels. The interaction is revealed in a compensatory pattern such as longer VOTs followed by shorter vowel durations in both languages. An asymmetry is found in CV interaction in that the effect of consonant on vowel duration is greater than the VOT differences induced by the vowel. Prosodic effects are found such that the acoustic difference is enhanced between the contrastive segments under focal accent, supporting the paradigmatic strengthening effect. Positional variation, however, does not show any systematic effects on the variations of the measured acoustic quantities. Overall vowel duration and syllable duration are longer in English tokens but involve less variability across the prosodic variations. The constancy of syllable duration, therefore, is not found to be more strongly sustained in Korean CDS. The stylistic variation is discussed in relation to the listener under linguistic development in CDS.

• Physical Therapy Korea
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• v.12 no.1
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• pp.11-21
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• 2005

The purpose of this study was to investigate how COP displacement of a hemiplegic foot in stance phase during gait is related to clinical balance measures and the recovery stage in hemiplegic stroke patients. Twenty-eight functionally ambulant hemiplegic patients who had suffered from strokes and thirty age-matched healthy subjects participated in this study. COP parameters were calculated. Clinical balance was measured using the Functional Reach Test (FRT) and Timed Up and Go Test (TUGT). The recovery stage, proprioception, and clonus of the ankles or lower extremities were also measured for physical impairment status. The COPx max-displacement in the medial-lateral side of the stroke patients was significantly longer than that of the normal group (p=.038). The COPy max-displacement in the anterior-posterior side of the stroke patients was significantly shorter than that of normal group (p<.001). Significant differences in the COPx and COPy displacement asymmetry index were found between the two groups (p<.01). The FRT was correlated with the COPx displacement (r=.552) and COPy displacement (r=.765). The TUGT was correlated with the COPy displacement (r=-.588) only. The recovery stage of the lower extremities was correlated with COPy displacement (r=.438). The results of the study indicate that the characteristic of COP displacement in hemiplegic feet in stance phase during gait is related to balance ability and recovery in stroke patients. COP parameters acquired by the mapping of foot pressure in stance phase during gait will provide additional useful clinical information. This information can be used by clinicians to assess objectively the pathologic gait with other diseases and to evaluate the therapeutic effects on gait in stroke patients.