• Title/Summary/Keyword: Difference in difference(DID)

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C Ball speed by a professional baseball player, and study of comparison of uniform rotational speed by the shoulder joint (프로야구 투수의 볼 스피드와 견관절의 등속성 회전력 비교 연구)

  • Park, Sung-Jin;Park, Young-Jin
    • Korean Journal of Applied Biomechanics
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    • v.16 no.1
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    • pp.81-88
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    • 2006
  • Present study is to know the relation with throwing speed according to the uniform torque by the shoulder joint, over 20 persons of professional baseball, and were measured the uniform torque by the shoulder joint accordance with throwing speed between (A-low speed) and (B-high speed) of each group. In the present study, three components were measured, and analyzed with having an approximated output value appearing by changing angular velocity, and in $30^{\circ}/sec$, the maximum strength of muscles was measured, and in$210^{\circ}/sec$, the points of endurance strength of muscles were measured and analyzed, and the following result could be obtained. 1. In muscles strength (peak torque)of inner rotation, and outer rotation for respect to each speed of shoulder joint, though there did not appear outstanding difference between A group and B group in the $30^{\circ}/sec$, it showed that group B has priority in a little. Also in outer rotation by shoulder joint, though there appeared the same difference between A group and B group, B group is tended to be prior to A group in a little. 2 In the view of muscles strength (peak torque)of inner rotation, and outer rotation for respect to each speed of shoulder joint, though there did not appear outstanding difference between A group and B group in the $30^{\circ}/sec$, it showed that group B has priority in a little. Also in outer rotation by shoulder joint, though there appeared the same difference between A group and B group, B group is tended to be prior to A group in a little. 3. In the view of muscles strength(peak torque)of inner rotation, and outer rotation for respect to each speed of shoulder joint, though there did not appear outstanding difference between A group and B group in the $30^{\circ}/sec$, it showed that B group has priority in a little. Also in outer rotation by shoulder joint, though there appeared the same difference between A group and B group, B group is tended to be prior to A group in a little. 4. In the view of peak torque for respect to the weight accordance with each velocity of shoulder joint, there did not appear outstanding difference between A group and B group. In outer rotation by the shoulder joint, there was not appeared clear difference between A group and B group. 5. In the concern of the peak torque for respect to the weight accordance with each velocity of shoulder joint, there did not appear outstanding difference between A group and B group in $30^{\circ}/sec$. In outer rotation by the shoulder joint, there was not appeared clear difference between A group and B group. 6. In the concern of the peak torque for respect to the weight accordance with each velocity of shoulder joint, there did not appear outstanding difference between A group and B group in $210^{\circ}/sec$. In outer rotation by the shoulder joint, there was not appeared clear difference between A group and B group. As conclusion, there did not appear a correlation of uniform torque by shoulder joint versus the speed throwing by a pitcher of professional base ball.

Changes in the Clothing Expenditure using Difference in Difference Model: Comparison between Korean and U.S. Households (이중차이 모형을 적용한 1990년대 중반 이후 한국과 미국소비자의 피복비 지출 변화 분석 및 비교)

  • Lee, Mi-Young
    • Korean Journal of Human Ecology
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    • v.21 no.2
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    • pp.349-362
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    • 2012
  • This paper explores differences demonstrated by changes of consumers' clothing expenditure in Korea and the United States since the mid-1990s. Evidence for this study was extrapolated from annual data provided by the Household Expenditure Survey, which was carried out in Korea between 1996 and 2008, and the Consumer Expenditure Survey, which was carried out in the United States during the same time period. The results include: (1) The proportion of the clothing expenditure decreased during the subject period in both Korea and the United States; (2) The decrease in proportional clothing expenditure was greater in Korea than in the United States; (3) Although the relative prices of clothes decreased greatly during this period in both countries, it was determined that the decrease in clothing prices in the United States was greater when compared to those in Korea; and (4) By using the DID(Difference in difference) model, the author contends that a decrease in clothing purchases contributed to the decrease of prices for clothing in the United States, while in Korea, the decrease in prices for clothing was also impacted by other factors including changes in household expenditures for education and communication.

A study on the Need for Curriculum Contents in each Sub-area of High School Home Economics Education (고등학교 가정과 교육을 위한 교과과정 영역별 필요도)

  • 이금남;김행자;안영희;이남기
    • Journal of Korean Home Economics Education Association
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    • v.8 no.1
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    • pp.1-10
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    • 1996
  • This study aims at finding a new home economics education which will include male and female students as its teaching objects, and then providing home economics teachers with useful materials. For this purpose I examined analized male and female the upper secondary school students’and parents’recognition and demand to the home economics education The conclusion of this study is summarized as follows: 1. There was significant difference between male students(73.7%) and female students(89.8%) in the necessity for studying Home Economics(P<.001). In the necessity of Home Economics education, male students emphasized the spiritual part but female students emphasized the functional part. In part of parents, there was no significant difference between fathers(95.5%) and mothers(96.4%). 2. The necessity of each part in the contents of Home Economics 1) In the part of family, there was significant difference between male and female students in the true nature of family, the role and responsibility of family, and the laws relating to family(P<.001). There was significant difference between mothers and fathers in the true nature of family and the role and responsibility of family. Fathers and male students emphasized the true nature of family and the role and responsibility of family more than mothers and female students did. 2) In the Home management and economy parts, there was significant difference between male and female students in the significance of home management(P<.001), the relation of family to society(P<.001), and fluctuating measures for home economy. There was significant difference between fathers and mothers in the relation of family to society(P<.05). Fathers and male students emphasized the relation of family to society more than mothers and female students did. Mothers, male and female students emphasized the importance of the protection of consumers. 3) In the clothes part, male students emphasized the role of clothes, the disign and making of clothes(P<.001), the present situation of the resources of clothing and the distribution of clothes (P<.05) more than female students did. 4) In the part of food, there was significant difference between male and female students in the kinds and function of nutritive elements(P<.05). Parents and students emphasized the importance of selecting good food. 5) In the part of housing, male students emphasized home planning, and arrangements and facilities of house more than female students did. Female students emphasized the interior of the house(P<.05). Fathers emphasized the planning of a residential space and arrangements and facilities of a house(P<.05) more than mothers did. 6) In the parts of human development and upbringing, and upbringing, male students emphasized the significance of being parents, family planning and the population problem(P<.001), pregnancy and delivery(P<.01), and the chracteristic of juvenile development(P<.05) more than female students did. Parents and students emphasized the importance of prevention and countermeasures for diseases and the significance of being parents.

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Economic Structure Analysis According to Old Age Household Type (노인가계 유형별 경제구조 분석)

  • Han, Su-Jin;Seo, Ji-Soo
    • Journal of Families and Better Life
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    • v.26 no.2
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    • pp.83-101
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    • 2008
  • This research performs a multi comparison between the age of old households and the economic structure according to accommodation type as well as analyzing the economical structural difference of each type based on the features of aged households. The paper classified aged households into 3 groups according to age distribution. The economic structure analysis according to the age of old households and accommodation type was shown as follow: First, the economical structural analysis based on the age of old households showed a statistical difference in the total, labor, business, property and transfer income variables according to the age of each sample group. However, the non-business income and liabilities did not show a significant difference. Second, in the analysis of different economic earnings and initial expenses of middle-aged households according to the age distribution group showed a disparity in the total, labor, business, property, and transfer income variables according to the age of each sample group. However, aged households showed a statistical difference in total, labor, business and transfer income variables. Third, in the analysis of difference in the expense provision and size of consumption, there was a statistical difference in the expense variables of total consumption, food, dining out, electricity, water, furniture, kitchen supplies, clothing, shoe, education, culture, entertainment, transportation, and communication. Fourth, in the analysis of difference in the size of consumption expense, the initial and middle-aged households showed a statistical difference in the total consumption, food, dining out, electricity, water, furniture, kitchen supplies, clothing, shoe, education, culture, entertainment, transportation, communication, and consumption expense variables. However, the analysis of aged households has shown a statistical difference in the total consumption, food, dining out, electricity, water, furniture, kitchen supplies, clothing, shoe, education, culture, entertainment, transportation, and communication expense variables. The study found a statistical difference in the expense for hygienics that did not appear in the initial and middle-aged households.

The Effect of Balance between General Walking Exercise and Power Walking Exercise

  • Kim, Shin Gyun;Kim, Chang Sook
    • Journal of International Academy of Physical Therapy Research
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    • v.4 no.2
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    • pp.566-572
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    • 2013
  • This study aims to compared effect of balance between general walking exercise and power walking exercise. Twenty subjects were classified into two groups, general walking exercise(n=10) and power walking exercise(n=10). As a result, two group showed difference within the group and there is significant difference between two groups. 1) In compared static balance of sway area at pre-post test to exercise group, general walking exercise group did not change significantly. however, power walking exercise group did change significantly. and At sway distance, two group showed significant changes. 2) In compared Static balance between the groups sway area and sway path at pre-post test, two group showed significant changes. 3) In compared dynamic balance of center distance at pre-post test to exercise group, general walking exercise group was no significant difference in all directions. power walking exercise group was significant difference in all directions. 4) In compared dynamic balance between the groups sway area and sway path at pre-post test, there was no significant difference in leftward, rightward, forward directions and was significant difference in backward, overall direction. Therefore, power walking exercise can be recommended promote balance.

The Effects of Aging and Gender on Distortion Product Otoacoustic Emissions (정상청력인에서 나이와 성별에 따른 DPOAE의 특성)

  • Hong, Bin-Na;Nam, Sang-Gil;Kim, Jin-Sook
    • Speech Sciences
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    • v.11 no.4
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    • pp.163-171
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    • 2004
  • The primary goal of the present study was to explore more detailed evidence for the influence of aging and gender effects on the capability of Korean healthy, ears to generate DPOAEs. DPOAEs were examined in series of human subjects, with clinically nonnal hearing, ranging in age from 10 to 65 years. All 60 Koreans were divided into 6 age groups. Each age group included 10 participants, 5 females and 5 males. The gender effects on the difference between the absolute amplitude and noise floor value in DPOAEs did not exist. The difference increased as the frequency increased. The aging effects on the difference between the absolute amplitude and noise floor value in DPOAEs did exist. The difference increased as the frequency increased but orderly age effects could not be found. The principle finding was that, when compared between emissions in young and old ears, DPOAEs accurately tracked the systematic deterioration of high-frequency hearing in aging individuals. Such results support the need to reestablish the criterion for interpretation of DPOAEs in the elderly.

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Analysis of Regional Effects of the Seasonal Management Policy on Coal-fired Power Plant Using Difference-in-difference Method (이중차분법을 이용한 석탄화력발전소에 대한 미세먼지 계절관리제의 지역별 효과 분석)

  • Kang, Heecha
    • Environmental and Resource Economics Review
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    • v.31 no.3
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    • pp.343-365
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    • 2022
  • This paper tries to identify the effect of reducing PM2.5 concentration of the First Seasonal Management Policy implemented by Korean government by using statistical method. In particular, this paper tests the hypothesis that this policy effect may differ by region (west-coast, south-coast, and east-coast). To this end, this paper analyzed only pure policy effects by removing temporal abnormalities such as COVID-19, warm winter temperature during the policy implementation period (December 2019 to March 2020) by using the difference-in-difference method (DID). As a result of the analysis, this policy had the effect of reducing PM2.5, but the effect is not homogenous by region. In particular, PM2.5 reducing effect is the largest in west-coast region and south-coast region folllows, but its effect is not statistically significant in the east-cost region. In conclusion, this paper drew implications that the current Seasonal mamangement policy which is implemented regardless of the regional difference needs to be changed.

The Effectiveness of Metacognitive Instruction Models on the Acquisition of Magnetic Field Concepts (초인지 수업 모형이 자기장 개념 형성에 미치는 효과)

  • Lee, Hee-Jung;Kang, Dae-Hun;Paik, Seoung-Hey
    • Journal of Korean Elementary Science Education
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    • v.22 no.2
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    • pp.149-155
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    • 2003
  • The objective of this research was to study the impact of metacognitive lesson models on the formation of magnetic field concepts. The subjects of this research was eighty students from two sixth grade classes. One class of forty of these students was the experimental group, which the metacognitive strategic lesson model was applied, and the other class of forty students was the control group which the traditional lessons were conducted. As the result of the experiment, the experimental group and the control group, which previously did not show difference in terms of achievement of conceptualizing magnetic field, displayed a significant difference. According to the comparison between the pre-experiment test on the students' previous concepts and the achievement of the students after the experiment, the middle group showed difference between the experimental group and the control group in a small degree. The lower group showed a notable difference between the two groups and the higher group showed no difference. In terms of achievements shown in different questions asked, there was little difference in the questions that were stated in the textbook while there was a significant difference in the questions that applied the contents of the textbook. The higher academic group, according to the test on the previous concepts, did not show much difference between the experimental group and the control group when they were asked about the concepts of the textbook. In terms of the comparison in the metacognitive levels, both the higher and lower metacognitive experimental groups' average grade was higher than the control groups' and showed an important statistical difference.

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Intramedullary Screw Fixation for Clavicle Shaft Fractures: Comparison of the Anterograde versus the Retrograde Technique

  • Rhee, Yong Girl;Cho, Nam Su;Cho, Sung Whan;Song, Jong Hoon
    • Clinics in Shoulder and Elbow
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    • v.19 no.1
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    • pp.8-14
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    • 2016
  • Background: The purpose of this study was to investigate the difference between two nailing approaches of intramedullary screw fixation, the retrograde nailing versus the anterograde nailing, on the radiological and clinical outcomes in patients with clavicle shaft fractures. Methods: From April 2002 to August 2014, we enrolled a total of 22 patients with clavicle shaft fractures to participate in this study. Twelve patients received retrograde intramedullary nailing and 10 received anterograde nailing. The average duration of follow-up was 12 months. In all the patients, we took follow-up radiographs of the anteroposterior and the axial views to assess the postoperative radiological outcomes. We measured the visual analogue scale (VAS) score, American Shoulder and Elbow Surgeons (ASES) score, and the range of motion (ROM). Results: Clinically, we did not find a statistically significant difference in the retrograde group and the anterograde group in terms of the duration to bone union, the VAS score the ASES score and the ROMs. Radiologically, we found that the difference in the clavicle shortening of the affected arm and the unaffected arm did not show a statistically significant difference at the immediate postoperative assessment. we found that the difference in the clavicle shortening of the affected arm between the immediate postoperative and the final follow-up value did not show a statistically significant difference. Conclusions: We found that both the retrograde nailing and the anterograde nailing gave a favorable outcome for clavicle shaft fractures. Although we saw evidence of clavicle shortening after intramedullary screw fixation, this was not a factor that influenced clinical outcome.

What Is the Difference between Chinese and Japanese FTAs?

  • Kang, Da-Yeon;Jeon, Young-Seo
    • Journal of Korea Trade
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    • v.24 no.5
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    • pp.1-17
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    • 2020
  • Purpose - This paper tries to estimate the effects of China's and Japan's free trade agreement (FTA) by panel generalized least squares (GLS). Design/methodology - The GLS model includes the basic gravity theory and Difference in Difference (DD) method to divide FTA conclusion countries and non-FTA conclusion countries with China and Japan. In order to empirically research the difference between Chinese and Japanese FTAs, we use the Difference in Difference in Difference (DDD) method. Findings - This paper finds the distance variable has more influence on Japanese than Chinese trade. The exchange rate indicates that Chinese trade depends on export and Japanese trade has the structure of re-import; shows that the countries that concluded FTAs with China and Japan have more positive trade effects than those that did not; finds the Chinese FTA promotion effects greater than the Japanese FTA because China had pushed ahead with trade policy since joining the WTO in 2001. Originality/value - This study shows that a single country's FTA and trade policies are an important factor concerning not just the promotion of trade but also the issue of trade conflicts.