• Title/Summary/Keyword: difference-in-differences event study

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Kinetic Analysis of Proficiency in the Use of the Breathing of Korea Dance Movement (한국무용 동작 시 호흡사용의 숙련도에 따른 운동역학적 분석)

  • Na, An-Suk
    • The Journal of the Korea Contents Association
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    • v.14 no.9
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    • pp.131-140
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    • 2014
  • The purpose of this study was to kinetic analysis of using the skill of breathing korean dance movement will be to perform. To achieve the research objectives cheoyongmu Nakhwayousu the operation was performed. The selection of subjects like the following: Five people were skilled use of breathing and five unskilled person. The results are as follows. The skilled and the unskilled were no significant differences in the duration time. And the skilled and the unskilled z-axis position of the center of mass, there was a significant difference (p<.05). The skilled and the unskilled y-axis velocity of the center of mass, there was a significant difference of event 1 and event 4 (p<.05). And z-axis velocity of the center of mass, there was a significant difference of event 3 (p<.05). And the skilled and the unskilled Fx of GRF, there was a significant difference of event 2 and event 4 (p<.05). And Fy of GRF, there was a significant difference of event 1 and event 5 (p<.05). And Fz of GRF, there was a significant difference of event 4 (p<.05).

The Effects of Marriage and Childbearing on Labor Market Outcomes and Subjective Well-Being among Women (결혼과 출산이 여성의 노동시장 성과와 생활만족도에 미치는 영향)

  • Yoo, Inkyung;Lee, Jungmin
    • Journal of Labour Economics
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    • v.43 no.4
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    • pp.35-86
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    • 2020
  • We estimate the effects of marriage on women's labor market outcomes and subject well-being. To resolve the endogeneity problem of marital status and timing of marriage, we use the difference-in-differences event study method which compares the trends of the outcome before and after the event between treatment and control groups. For robustness, we use four different control groups. The results show that the probability of working drops significantly by about 10%p in the first year of marriage and the effect becomes as large as 46%p by the 5th year of marriage. Also monthly earnings decrease substantially. We find that marriage increases subjective well-being, while the effect is not persistent.

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Effects of the Frequency Band Pass Filter on the P300 Event-related Potential in the Working Memory (주파수 통과대역필터가 작업 기억 관련 사건관련전위 P300에 미치는 영향)

  • Park, Woongsik;Lee, Jeongwoo
    • Journal of The Korean Society of Integrative Medicine
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    • v.8 no.2
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    • pp.131-138
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    • 2020
  • Purpose : The purpose of this study was to investigate the effects of the frequency band pass filter on the P300 event-related potential in the working memory. Methods : The subjects were 20 women in their 20s who applied for participation in the experiment. Event-related potentials (ERPs) were elicited using 3-back tasks for the working memory, and were recorded from Fz, Cz, and Pz scalp electrodes. The high-pass filters were set to 0.01, 0.1, and 0.3 Hz for analysis purposes, and the low-pass filters were set to 30 and 15 Hz. The 3-back task was presented for a total of 100 times, among which 30 times were designated for the target stimulation (a matched number) and 70 times for the non-target stimulation (an unmatched number). The temporal interval between each stimulation was set at 1 second, while each time duration was randomly presented between 2 to 4 seconds. ERP were analyzed for the P300 recorded from Fz, Pz and Cz scalp electrodes. Results : Latency and amplitude had no significant interaction effects in both the high- and low-pass filters. For the main effects, the latency and amplitude of the P300 event-related potential had no significant difference in the high-pass filters, but the latency had a significant difference in the low-pass filter of Fz, and the amplitude had a significant difference in the low-pass filter of Pz. Conclusion : The results of this study showed that the less than 0.3 Hz high filters had no effects on the differences between the latency and amplitude of the P300 event-related potential in the working memory. The 30Hz low-pass filter, however, was found to be useful for recording the P300 event-related potential in the working memory.

Does the Pandemic Declaration influence the Firm Value of the Untact Firms? (팬데믹 선언이 언택트 기업의 기업가치에 미치는 영향: 투자자 마니아 가설을 중심으로)

  • Park, Su-Kyu;Cho, Jin-Hyung
    • Asia-Pacific Journal of Business
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    • v.13 no.1
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    • pp.247-262
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    • 2022
  • Purpose - The purpose of this study is to examine the impact of the Pandamic Declaration on 'untact firms' listed in KOSPI and KOSDAQ market in order to verify Investor Mania Hypothesis. Design/methodology/approach - This study collected financial data for 44 untact firms in KOSPI and KOSDAQ market. Then, we employed ESM(Event Study Methodology), EGARCH model and DID(Difference-In-Difference) for analysis. Findings - First, in contrast with the benchmarking index, KOSPI 200 which shows a negative (-) abnormal return trend, the untact firms have positive abnormal return trend consistently. Second, after the Pandemic Declaration, the variability of abnormal return for the untact firms is found to be significantly positive. Third, we find that the cumulative abnormal return and volatility of the untact firms significantly increase after the Pandemic Declaration. Research implications or Originality - Based on the Investor Mania Hypothesis, we confirm that the market potential of untact firms after the Pandemic Declaration is observed when compared with the KOSPI 200.

Relationships among the Elderly's Self-Esteem and Life-Adjustment according to Decision-Making Power in Their Family (노인의 가정내 의사결정권에 따른 자아존중감 및 생활적응)

  • Chi, Keum-Soo
    • Korean Journal of Human Ecology
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    • v.10 no.1
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    • pp.127-139
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    • 2001
  • The purpose of this study was to find out the relationships among the elderly's self-esteem and life-adjustment according to decision-making power in their family. Interview survey was conducted and were selected. 296 over age 60 who lived in Jeonju. Frequencies, Percentiles, Pearson's correlation, t-test, ANOVA and Duncan's method were utilized for data analysis. The findings of this study were as follows ; 1) Decision-making power of the elderly in family had significant differences according to sex, coresiding with married children, and the sum of monthly personal expenses. 2) Elderly's self-esteem had significant differences according to sex, the present job, the situation of a spouse, and the sum of the monthly personal expenses. 3) Elderly's life-adjustment had significant difference according to residence type, the present job, the situation of a spouse, religion, education, and the sum of the monthly personal expenses. 4) Clothing and food in family had significant differences according to sex. 5) The elderly men's self-esteem had positive relationship with housing, sons and daughters guidance, grandchildren care, and family event and etc. But the elderly women's self-esteem had positive relationship with food, grandchildren care, and family event and etc. 6) The elderly men's life-adjustment had positive relationship with clothing, food, housing, family economy, sons and daughters guidance, grandchildren care, and family event and etc. But the elderly women's life-adjustment had positive relationship with food, housing, sons and daughters guidance, grandchildren care, and family event and etc.

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Posttraumatic Stress in Fire fighters (소방대원의 외상후 스트레스 실태)

  • Koh, Bong-Yeun
    • The Korean Journal of Emergency Medical Services
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    • v.12 no.3
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    • pp.5-15
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    • 2008
  • Purpose : This study is a descriptive research to provide basic factors of posttraumatic stress in Firefighters. This study was carried out to develop the effective program for the fire fighters to cope with the posttraumatic stress following the disasters. Methods : The questionnaires were collected among fire fighters who serviced in K and I community from April 1 to June 30 in 2008. Total 304 questionnaires were analyzed by SPSS WIN program for descriptive statistics, Pearson's correlation coefficient and t-test. Results : 1. 48.0% of 300 fire fighters were at the age of 31-40, and 42.3% were under 30. 2. Work burden had a significant difference of 2.30 in low-risk group, 2.60 in high-risk group(t-value=-3.85, p=0.00). However, life event had no significant difference 0.79 event in low-risk group, 1.41 event in high-risk group(t-value=-2.27, p=0.24). 3. Concerning posttraumatic stress factors, there was positive correlation between mobilization impact level r=0.38(P<0.01), work burden r=0.38(p<0.01), and life event r=0.27(p<0.01). 4. According to the Symptom Check List-Revised(SCL-90-R), somatization had a significant differences(t-value=5.46, p=0.00), obsessive-compulsive(t-value=7.16, p=0.00), interpersonal sensitivity(t-value=6.15, p=0.00), depression(t-value=6.62, p=0.00), anxiety (t-value=7.33, p=0.00), hostility(t-value=5.94, p=0.00), phobia anxiety(t-value=6.85, p=0.00), paranoid ideation(t-value=5.55, p=0.00), psychotism(t-value=6.52, p=0.00) in low-risk and high-risk group. Conclusion : As a consequence, mobilization impact, work burden, and life event were the influential factors on posttraumatic stress. Also, high-risk group revealed significantly higher score on all 9 scales. The information obtained from surveys made recommendation to develop the intervention of stress management to control mobilization impact and posttraumatic stress.

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Effects of Occlusal Factors and Life Event Changes on Temporomandibular Disorders (측두하악장애에서 교합요인과 생활변화의 영향)

  • You-Me Lee;Kyung-Soo Han
    • Journal of Oral Medicine and Pain
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    • v.19 no.2
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    • pp.181-192
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    • 1994
  • There have been many different theories on the etiology of temporomandibular disorders(TMDs). The objective of the study was to investigate the effects of occlusal fctors and recent life event changes as prediposing fctor on the development of temporomandibjlar disorders. To evaluate the above predisposing factor, the author used T-scan system(Tekscan Co. U.S.A.) for quantitative occlusal analysis, clinical examination for occlusal state and Social Readjustment Rating Scale(SRRS) for recent life event change units (LCU). 63 patients with TMDs and 57 patients with malocclusion presented at Wonkwang University Dental Hospital participated in this study. The subjects were grouped by Angle's classification and presence of absence of TMDs and parafunctional oral habits. Data gained with regard to contact number, contact force, contact time, occlusal state(number of total teeth and occluding teeth, overjet, overbite) and occlusal interferences (protrusive posterior contact, nonworking side interference, and RCP-ICP slide) and recent life event changes. The data were processed and analysed by SAS statistical package program, The results of this study were as follows : 1. There were no significant differences on both quantitative occlusal contact analysis and occlusal state between TMDs group and Angle's malocclusion group. Also, there were no differences among the Angle's classifications. But amount of overjet in TMDs group were more greater than that of malocclusion group. 2. There was no difference on protrusive posterior contact, and balancing contact between TMDs group and Angle's malocclusion group. Premature contact was more frequent in malocclusion group, but RCP-ICP slide was more frequent in TMDs group. And RCP-ICP slide was more freqent in Angle's class II malocclusion than Angle's I or III malocclusion. 3. Life changes units in TMDs group were higher than those in malocclusion group. And recent life change units in group with parafunctional oral habit were higher than those in group without parafunctional oral habits. Clenching was the most common habit among parafunctional oral habits.

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N400 Event-related Potential and Gamma Band Activities during Visual Perception of Korean/English Words (한글 및 영어 단어의 시각적 인지 시 N400 사건관련 뇌전위 및 감마대역 활성화)

  • Yoon, Jin;Choi, Jung-Woo;Kim, Ja-Hyun;Kim, Kyung-Hwan
    • Journal of Biomedical Engineering Research
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    • v.29 no.6
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    • pp.477-483
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    • 2008
  • The observations of difference and similarity in brain activities involved in processing different languages have fundamental importance in cognitive neuroscience. The purpose of this study was to investigate the difference and similarity in temporal brain activation patterns due to the language difference during visual perception of Korean and English words under priming. Especially, we tried to find the difference in evoked spectral power in gamma-band, which is known to reflect feature binding. The stimulation was visually presented as word pairs belonging to same or different categories so that N400 event-related potential(ERP) was evoked. Average ERP analysis and spectral analysis of gamma-band activity(GBA) were performed on 12 normal Korean subjects. Several ERP components such as P1, N1, N400, and P600 could be identified consistently, and the differences in N1, N400, and P600 were observed. From the spectral analysis, we found that the evoked GBA(eGBA) was significantly larger for English at ${\sim}100$ ms poststimulus. The latency of the eGBA was also considerably delayed for English. Overall, the results on the ERP components and eGBA analyses seem to be commensurate with subjects' familiarity of each language, and the difficulty of perceiving words of each language. The methods of this study can also be applied for clinical purposes considering that the language-related processing can be greatly altered for the patients with neurological or psychiatric diseases.

Differential effects on the MICE sustainability and customer loyalty perceived by domestic and international attendees (내·외국인이 인식한 MICE 분야 지속가능성과 고객 충성도에 대한 차별적 효과에 관한 연구)

  • Cheng, Xiao Xi;Kim, Chul Won
    • Korea Science and Art Forum
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    • v.30
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    • pp.427-440
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    • 2017
  • The objective of this study is to explore differential effects of the sustainability perceived by domestic and international participants in the MICE (Meetings, Incentive Travel, Convention, and Exhibition) held in the Republic of Korea and to examine the relationship between customer loyalty and perception of the sustainable MICE. In this study, 30 sustainability variables for the MICE were extracted and tested by the factor analysis, representing four underlying dimensions: economic sustainability, social sustainability, environmental sustainability and event sustainability. The results revealed that significant differences in these four dimensions of the sustainable MICE were perceived by domestic and international participants. The largest difference were perceived by domestic and international participants with respect to the environmental sustainability factor. The mean scores indicated that international participants tended to give higher evaluations than domestic participants. Second, there were statistically significant relationships among economic, environmental, and event sustainability factors and customer loyalty from the perspective of international participants. For domestic participants, only event sustainability had a vital relationship with customer loyalty. The study implied how policy makers and the MICE managers should adopt four dimensions of sustainability to establish a harmonious and sustainable MICE practices.

Perspective Diversity of Domestic Stakeholders on Medical Device Adverse Event Reporting (의료기기 이상사례 보고에 대한 국내 이해관계자의 관점 차이)

  • Lee, Ye Jin;Yoon, Chiho;Choi, Soo Jeong;Kang, Youngjoon;Kim, Jin Kuk;Kwon, Bum Sun;Lee, You Kyoung;Nam, Ki Chang
    • Journal of Biomedical Engineering Research
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    • v.40 no.5
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    • pp.171-178
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    • 2019
  • This study was conducted to observe the differences in perspective of medical device adverse events and report exchange for domestic stakeholders. The post-market surveillance of medical device not only improves the usability and functionality of the device but also identifies new or growing risks caused by the device. APEC (Asia-Pacific Economic Cooperation) have established and operated post-market surveillance systems for medical devices based on IMDRF (International Medical Device Regulators Forum) and GHTF (Global Harmonization Task Force) guidelines. However, there are significant gaps in many aspects. It is essential to apply harmonized guidelines internationally but also to interpret and apply the guidelines consistently to report and exchange medical device adverse event in domestic. This study retrospectively analyzed the results of surveys conducted by providing examples of the adverse events and guidelines for post-market surveillance. The results of the study showed that there was a considerable difference in the judgment on the phase of using medical device for patient. In the case of medical device adverse event, different opinions shown according to knowledge and experience. Education and training are needed to have a harmonized perspective on the reporting and exchanging international guidelines of the adverse event for domestic stakeholders.