• 제목/요약/키워드: Difference-in-Differences(DID)

검색결과 1,346건 처리시간 0.026초

한국인 아동의 치궁발육에 관한 연구 (A LONGITUDINAL STUDY ON THE DEVELOPMENT OF DENTAL ARCHES IN KOREAN CHILDREN)

  • 허만욱
    • 대한소아치과학회지
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    • 제8권1호
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    • pp.25-36
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    • 1981
  • The purpose of this longitudinal study was to measure and analyze the width and length changes of dental arches at age 7 to 9. 66 children were selected for this study. Stone models obtained from these children were measured and analyzed annually. The results were as follow. 1. The widths of upper arch increased by age both in males and females except the region of second deciduous molars. 2. The widths of lower arch increased by age significantly both in males and females. 3. The lengths of dental arches increased by age both in males and females at anterior portion. ; did not increase at Posterior portion. 4. The upper widths of males were wider than those of females at age 9, but no significant difference were present at age 7 and 8. 5. The differences of the lower widths between males and females were not present except the region of the second deciduous molars (E-E) at age 7. 6. There were few differences between the lengths of males and females except the posterior lengthes at age 7. 7. The widths and lengths of upper arches were difinitely wider and longer than lower arches.

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성별에 따른 공적 자기의식, 신체이미지, 사회문화적 영향의 차이에 관한 연구 (Public Self-Consciousness, Body Image, & Socio-Cultural Influence on Gender Differences)

  • 이승희;이시원
    • 패션비즈니스
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    • 제13권5호
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    • pp.45-54
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    • 2009
  • The purpose of this study was to examine if there were differences in public self-consciousness, body image, and socio-cultural influence between males and females. Six hundred twenty-six adults participated in this study. For data analysis, descriptive statistics, t-test and reliability test were used. The result of this study is as follows. First, compared to males, females had higher scores on appearance orientation(AO), appearance evaluation(AE), and weight occupation(WP). Also females were more dissatisfied with their bodies such as lower body part or middle body part than males. That is, women had lower body image than men. Second, there was not significantly difference in self-esteem between males and females. Third, females had higher scores on public-consciousness than males did. Fourth, compared to males, females were more influenced by socio-cultural factors such as internalization and awareness. Finally, women had more higher scores on appearance behavior management than men. Based on these results, this study would provide more efficient strategies to reduce negative body image, especially in women.

PBL Scheme에 대한 WRF-CMAQ 민감도 분석 (Sensibility Study for PBL Scheme of WRF-CMAQ)

  • 문난경;김순태;서지현
    • 한국대기환경학회지
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    • 제27권6호
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    • pp.791-804
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    • 2011
  • Numerical simulations were carried out to investigate the impact of PBL (Planetary boundary layer) scheme implemented in WRF on the result of meteorological fields and CMAQ modeling. 25-day period, representing high ozone concentration, was selected for the simulations. The three WRF domains covered East Asia region, Korean Peninsula and Seoul metropolitan area. The sensitivity of WRF-CMAQ modeling to the various PBL schemes was assessed and quantified by comparing model output and against observation from the meteorological and the air quality monitoring network within the domain. The meteorological variables evaluated included temperature, wind speed and direction over surface sites and upper air sounding sites. The CMAQ variables included gaseous species $O_3$ and $NO_x$ over monitoring stations. Although difference of PBL schemes implemented in WRF, they did not appreciably affect the WRF and CMAQ performance. There are partially differences between non-local and local mixing scheme, but are not distinct differences for the results of weather and air quality. It is suggested that impact of parameterization of vertical eddy diffusivity scheme in CMAQ also need to be researched in the future study.

이미지 상상훈련을 적용한 핵심기본간호술 실습교육이 간호대학생의 임상수행능력, 자율실습시간에 미치는 효과 (The Effects of Imagery Training on Outcomes of Clinical Competence, Voluntary Practice Time and Nursing Skills)

  • 김수연
    • 한국간호교육학회지
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    • 제23권1호
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    • pp.76-85
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    • 2017
  • Purpose: The aim of this study was to explore the effects of imagery training on outcomes of clinical competence, voluntary practice time and basic nursing skills performance during a core basic nursing skills course. Methods: The design was a pre-post test design with two groups consisting of 88 nursing 3rd-year students. Clinical competence was assessed with a pre-post test, and basic nursing skills' performance and voluntary practice time were assessed at the post-test point. Data were collected from March, 2016 to June, 2016. Results: The pre-post differences of all subcategories of clinical competence were significantly improved in the experimental group (p<.05). but the control group did not show significant differences in the teaching/coordinating and professional development areas (p>.05). The experimental group practiced 1.33 hours more than the control group in voluntary practice. The two groups showed no significant difference in basic nursing skills' performance (p>.05). Conclusion: Imagery training during a core basic nursing skills course showed positive effects on nursing students' clinical competence improvement and increase of voluntary practice time.

한국어와 일본어 단모음의 유사성 분석을 위한 실험음성학적 연구 (An Experimental Study on the Degree of Phonetic Similarity between Korean and Japanese Vowels)

  • 권성미
    • 대한음성학회지:말소리
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    • 제63호
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    • pp.47-66
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    • 2007
  • This study aims at exploring the degree of phonetic similarity between Korean and Japanese vowels in terms of acoustic features by performing the speech production test on Korean speakers and Japanese speakers. For this purpose, the speech of 16 Japanese speakers for Japanese speech data, and the speech of 16 Korean speakers for Korean speech data were utilized. The findings in assessing the degree of the similarity of the 7 nearest equivalents of the Korean and Japanese vowels are as follows: First, Korean /i/ and /e/ turned out to display no significant differences in terms of F1 and F2 with their counterparts, Japanese /i/ and /e/, and the distribution of F1 and F2 of Korean /i/ and /e/ in the distributional map completely overlapped with Japanese /i/ and /e/. Accordingly, Korean /i/ and /e/ were believed to be "identical." Second, Korean /a/, /o/, and /i/ displayed a significant difference in either F1 or F2, but showed a great similarity in distribution of F1 and F2 with Japanese /a/, /o/, and /m/ respectively. Korean /a/ /o/, and /i/, therefore, were categorized as very similar to Japanese vowels. Third, Korean /u/, which has the counterpart /m/ in Japanese, showed a significant difference in both F1 and F2, and only half of the distribution overlapped. Thus, Korean /u/ was analyzed as being a moderately similar vowel to Japanese vowels. Fourth, Korean /${\wedge}$/ did not have a close counterpart in Japanese, and was classified as "the least similar vowel."

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성인 여성의 식사 동반자 여부가 대사증후군에 미치는 영향 (The Effect of a Dietary Companion on Metabolic Syndrome in Adult Women)

  • 최한교;김혜진;강석정
    • Journal of Korean Biological Nursing Science
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    • 제23권2호
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    • pp.100-109
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    • 2021
  • Purpose: This study aimed to compare the differences in the prevalence of metabolic syndrome between menopausal women and women of childbearing age and to determine the risk of metabolic syndrome among women in each group depending on whether they eat alone. Methods: Data of 1,813 women from the seventh Korea National Health and Nutrition Examination Survey (2016) were used. The collected data were analyzed using SPSS 20.0, and complex sample frequency analysis, descriptive statistics, complex sample cross analysis, complex sample general linear regression, and complex sample logistic regression analysis were performed. Results: According to the results of the study, there was no difference in the prevalence and risk of metabolic syndrome according to the presence of companions during meals between women of childbearing age and post-menopausal women, but there was a difference in health behavior. In other words, women of childbearing age who ate alone had a lot of experience of drinking, and menopausal women who ate alone did not tend to make any efforts to control their weight and did not perform aerobic exercise. In particular, the negative health behavior of menopausal women who ate alone increased the risk of prevalence of metabolic syndrome. Conclusion: The findings indicate that, for women who eat alone, interventions to prevent metabolic syndrome should be differentiated before and after menopause. Therefore, it is suggested to offer an educational program to prevent metabolic syndrome in women of childbearing age as well as provide regular assessments to diagnose metabolic syndrome and health behavior improvement programs for menopausal women.

Impacts of Financial Constraints on Firm Value for KONEX Listed Firms

  • Zhang, Xue Dong;Kang, Shinae
    • 융합경영연구
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    • 제9권4호
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    • pp.1-8
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    • 2021
  • Purpose: This study empirically investigates what factors contribute to corporate value in the Korea New Exchange (KONEX) market and determines whether financial constraints contribute any effect on it. Research design, data and methodology: A fixed-effect panel regression model was utilized to analyze financial constraints on firm value for KONEX listed firms through the fiscal period from 2013 to 2020. Results: we find that firms' research and development, volatility, size, and sales growth give significant impacts to firm value, but the significance and direction are different. In addition, no significant relationship exists between the largest shareholder's equity ratio and firm value in all models. The debt-to-equity ratio did not show a significant relationship with corporate value. A significant negative relationship was found between R&D and corporate value in the entire sample. Volitility exhibited a positive relationship with corporate value in the entire sample and financially unconstrained companies. Firm size presented a significant negative relationship with company value in all models. Sales growth showed a significant negative relationship with corporate value in financially constrained companies. Conclusions: No difference is found between financially constrained and unconstrained companies in the KONEX market. We can infer that KONEX companies have a large difference with KOSPI or KOSDAQ. Further analysis is needed on the differences among these markets.

Effects of Squatting with Different Foot Positions on Muscle Activations in Subjects with Genu Varum

  • Seo, JoonHo;Chang, JongSung;Lee, MiYoung
    • The Journal of Korean Physical Therapy
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    • 제31권2호
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    • pp.76-81
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    • 2019
  • Purpose: This study examined the effects of squatting with different foot positions on the muscle activation of the vastus medialis oblique (VMO) and vastus lateralis (VL) muscles in subjects with genu varum. Methods: Thirty four subjects participated in this study. Surface electromyography was used to measure the muscle activation of the VMO and VL muscles at the knee angles ($15^{\circ}$, $60^{\circ}$) at three foot positions (internal rotation, neutral position, external rotation) during squatting. Results: Muscle activation differences at different knee angles and foot positions differed significantly between the VMO and VL muscles in both the varus and normal groups. In addition, there was a significant difference according to the knee angles with the foot in external rotation in the VMO and VL ratio. In the varus group, however, the VMO and VL ratio were significantly different only with the feet in internal rotation. In the muscle activation changes of the knee angle differences in the foot position, there was no significant difference in the varus group, but both the VMO and VL muscles were significant different in the normal group. Conclusion: In both groups, regardless of the foot position, muscle activation of the VMO and VL muscles increased with increasing knee flexion angle. In the normal group, when squatting with the feet in external rotation, the VMO and VL muscles activations increased with increasing knee angle. In the varus group, however, the foot position did not affect the VMO or VL muscle activation. This study shows that subjects with genu varum and normal subjects have different VMO and VL muscle activation patterns during squat exercises.

THE EFFECT OF PALM OIL SUPPLEMENTATION IN ISOCALORIC AND ISONITROGENOUS DIETS OF BROILERS

  • Panja, P.;Kassim, H.;Jalaludin, S.
    • Asian-Australasian Journal of Animal Sciences
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    • 제8권2호
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    • pp.151-158
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    • 1995
  • A study was carried out to investigate the effect of palm oil supplementation on the growth, carcass composition and fatty acid distributions of the broilers fed isonitrogenous and isocaloric diets. This study showed that palm oil supplementation increased feed consumption, weight gain and nitrogen intake. Feed conversion improved at higher fat inclusions, but not significant. Male birds consumed significantly more feed than females resulting in significant increase in energy consumption and weight gain. Increaseing fat content in the ME:P constant diet did not produce significant difference in the fat content of the chicken. Fatty acids content of the diet exert varying effects of the composition and distribution of fatty acids in muscles of the chicken. The fatty acids found in larger amount in the breast and thigh muscles were palmitic, oleic and linoleic. The fatty acids of the breast and thigh muscles were found to correspond the fatty acids of the diets. There were no differences in the fatty acids distribution patterns between the sexes.

Measurement and Analysis of Arousal While Experiencing Light-Field Display Device

  • Choi, Hyun-Jun;Kim, Noo-Ree;Park, Hyun-Rin
    • Journal of information and communication convergence engineering
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    • 제18권3호
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    • pp.188-193
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    • 2020
  • In this paper, we examine whether the 3D image experience through a light-field display device showed the difference in the arousal of the user compared with the 2D image experience. For our experiment, the Looking GlassTM (LG) was used as a lightfield display device that provided 3D images, and 2D images were provided by digital and printed images. The subject's facial behavior during each media experience was recorded for analysis and the degree of arousal was measured by FaceReaderTM. As a result, the first image presented in the first order among the three kinds of images showed that there was a statistical difference in the degree of arousal between the three media. However, no significant differences were found between the three media in the other images. This may be because the arousal did not increase from the experience of the second image through the LG, owing to habituation. In conclusion, the 3D imaging experience may appear in the beginning, but does not continue.