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

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Effect of lumbar extensor strength according to lumbosacral angle change on chronic lumbar back pain patients (만성요통환자의 요천추 각도가 요부신전 근력에 미치는 영향)

  • Kim Kyoung-Tae;Park Rae-Joon
    • The Journal of Korean Physical Therapy
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    • v.16 no.1
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    • pp.14-31
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    • 2004
  • The Purpose of this study was to investigate the change of lumbar extensor strength according to lumbosacral angle on chronic lumbar back pain patients. For this investigation lumbar extensor strength was administered to 60 patients who were diagnosed chronic lumbar back pain The subjects was to investigate lumbosacral angle in standing position and it were calculated lumbar extensor strength by using Medex. The result of this study summarized are as follows ; 1. Total experimental group exhibited significantly higher difference than control group in lumbar extensor strength among all degree lumbosacral angle. 2. In the relationship between experimental group and control group in lumbar extensor strength among lumbosacral angle, all degree difference was revealed II, I, III order. 3. In the relationship between experimental group and control group in lumbar extensor strength among lumbosacral angle, I group difference was did not. 4. In the relationship between experimental group and control group in lumbar extensor strength among lumbosacral angle, all degree among II group was noted significantly difference except 24, 72 angle. 5. In the relationship between experimental group and control group in lumbar extensor strength among lumbosacral angle, control group was revealed higher muscle strength 48, 60, 72 angle, however no significantly difference was noted 0, 12, 24 angle. The study was objected difference of other group in both of experimental and control group. Because lumbar extensor weakness with bad position was gradually increased back pain, to Maintain normal lumbosacral angle befor exercising lumbar extensor strength was most important.

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Impact of Concurrent Inspiratory Muscle Training and Tape on Inspiratory Muscle Strength, Endurance and Pulmonary Function (들숨근 훈련과 테이핑 동시적용이 호흡의 근력, 지구력, 폐기능 향상에 미치는 영향)

  • Lee, Minsoo;Kim, Myungchul;Ahn, Chungjoa
    • Journal of The Korean Society of Integrative Medicine
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    • v.2 no.3
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    • pp.65-73
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    • 2014
  • Purpose: The purpose of this study was to identify the effect of a kinesio tape on inspiratory muscle training(IMT) to improve muscle strength, endurance and pulmonary function. Methods: Healthy 20 males were divided into IMT group (control group) and IMT with tape group (experimental group). The same IMT program was applied to both groups using the Respifit S for four weeks, three times a week, a total 12 times. To exprimental group, kinesio tape was applied on the inspiratory agonist diaphragm and the accessory inspiratory muscle scalene, sternocleidomastoid, pectoralis minor. The inspiratory pulmonary muscle strength was measured by the maximal inspiratory pressure (PI max) and minute volume (MV) using the Respifit S and the pulmonary function were measured peak expiratory flow (PEF), forced vital capacity (FVC), forced expiratory volume in 1sec (FEV1), FEV1/FVC using the Spirometer and compared before and after. Results: Results showed that the PI max in the two groups increased significantly and experimental group increased more effectively than that of control group. However, only MV showed a significant increase in experimental group but was not significantly different between the two groups. PEF and FEV1/FVC are significantly increased in both groups, but they did not make much difference between two groups, and the FVC for the two groups did not increase significantly. FEV1 increased significantly only with control group, but did not make a difference with experimental group. Conclusion: These result show that the PI max value for experimental group increased significantly than that of control group. Therefore kinesio tape maximizes inspiratory muscle exercise effect on muscle strength improvement. However, because of the short experimental period and difficulty in subject control, increase values of the others did not show a significant difference. In other words, kinesio tape did not show maximizing the inspiratory muscle exercise effect to improve endurance and pulmonary function.

Empirical Analysis of the Effect of EU ETS on the CO2 Emission (유럽공동체 배출권거래제 도입 효과에 대한 실증분석)

  • Kim, Hyun;Lee, Gwanghoon
    • Environmental and Resource Economics Review
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    • v.19 no.4
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    • pp.875-896
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    • 2010
  • Using the difference in differences (DID) estimation method, this paper analyzes the effect of European Union's Emission Trading Scheme (EU ETS) on the reduction of per capita $CO_2$ emission among the twenty five participating countries. For this, the panel dataset of forty two European countries for the period 1990~2007 is constructed. Special attention is paid to the bias of the standard errors in the DID estimation due to the presence of serial correlation in the error terms. The results shows quite a robust effect of EU ETS on the reduction of per capita $CO_2$ emission among the participating countries regardless of the calculation methods of standard errors. The results also shows that the increased implicit tax rate on energy has a robust effect on the reduction of per capita $CO_2$ emission. On the contrary, the estimation results regarding the effects of per capita GDP and population density on the per capita $CO_2$ emission seem inconsistent. In particular, the environmental Kuznets curve is not statistically supported with the use of robust standard errors.

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Assessing Korean Middle School Students' Spatial Ability: The Relationship with Mathematics, Gender, and Grade

  • Park, Sung Sun;Yoon, So Yoon
    • Research in Mathematical Education
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    • v.16 no.2
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    • pp.91-106
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    • 2012
  • Spatial ability has been valued as a talent domain and important skill in mathematics education because it enhanced an intuitive view and an understanding in many areas of mathematic. In addition, spatial ability highly correlates with mathematics achievement, indicating its crucial role in success in mathematics education. Some researchers founded gender differences in mathematics and spatial ability, and indicated that spatial ability served as a mediator of gender difference in mathematics. This study explored the spatial ability of 349 Korean middle school students (Grade 7-9), and investigated the association among students' spatial ability and their mathematics achievement, gender, and grade. The result of this study shows that spatial ability correlates positively with mathematics achievement. While gender difference did not exist in mathematics, significant gender difference existed in spatial ability favoring male students.

DIMENSIONAL STABILITY OF IMPRESSION BODY USING SILICONE INDEX TOOTH TRAY IMPRESSION SYSTEM (Silicone Index Tooth Tray를 이용한 인상체의 체적안정성에 대한 연구)

  • Lee Kyu-Young;Jeong Seung-Mi;Shim June-Sung;Choi Byung-Gap;Lee Keun-Woo
    • The Journal of Korean Academy of Prosthodontics
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    • v.43 no.5
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    • pp.622-632
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    • 2005
  • Statement of problem: Silicone Index Tooth Tray impression system which does not use gingicord has a shortcoming. It takes time to remove internal wall of Silicone Index Tooth Tray for space of wash impression material. Purpose: This study was to evaluate whether providing certain space to impression body can prevent from doing complicated laboratory work. Material and methods: After mounting metal dies with shoulder and chamfer margins arbiturarily, SITT was produced using $Blu-mousse^(R)$. In one experimental group, wash impression was taken using $Fit-tester^(R)$ without removing interior surface of SITT and in the other group, wash impression was taken using $Fit-tester^(R)$ providing 0.5mm space in the SITT and then compared the differences in two groups. Results: 1. There was no significant difference between a group which did not allow space and a group which granted equal 0.5mm space. 2. There was no significant difference between gingival diameter, occlusal diameter of metal die that has shoulder margin and gingival diameter, occlusal diameter of metal die that has chamfer margin. 3. There was no significant difference between a group which did not take pick-up impression and a group which took pick-up impression through relining method using SITT 4. There was no significant difference between a group that poured immediately after taking primary impression and a group that poured after removing poured stone die. Conclusions: When taking an impression of an abutment using SITT impression system, it is considered to obtain clinically identical results between a group that did not grant a 0.5mm space within SITT for wash impression and a group which invest a space. Furthermore, it is considered possible to produce an individual die through secondary pouring.

The Effect of the Use of 4th Industrial Revolution Technology on Export Performance (4차 산업혁명 기술 활용이 수출성과에 미친 영향)

  • Sehwan Oh
    • Korea Trade Review
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    • v.46 no.2
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    • pp.323-335
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    • 2021
  • With the advent of the 4th Industrial Revolution, there is a rising interest in the impact of these changes on Korea's trade. While the previous studies related to the 4th Industrial Revolution are very limited in the field of trade research, this study attempts an empirical analysis regarding the effect of the use of the 4th Industrial Revolution technology on the performance of exporters, based on the data of the Survey of Business Activities during 2017-2019 by the Korean government statistical office. Through the empirical analysis in combination with the propensity score matching (PSM) and the difference-in-difference (DID) analysis, this research confirms that the use of the 4th Industrial Revolution technology has a positive effect on the export performance of Korean exporters.

Requirements and satisfaction with medical masks (보건용 마스크의 요구사항 및 만족도)

  • Younghee Park
    • The Research Journal of the Costume Culture
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    • v.31 no.1
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    • pp.1-17
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    • 2023
  • This study analyzed requirements for medical masks and difference in satisfaction based on demographic characteristics and side effects experience caused by wearing medical masks. Three factors related to requirements for medical masks were identified: wearing comfort and usability, blocking function for harmfulness, and design. As a result of the difference analysis for requirements of medical masks based on demographic characteristics, all three factors showed a significant difference in gender and occupation. Design did in age and monthly income. As a result of the presence or absence of breathing difficulties experience, design factor was significant. As a result of the presence or absence of skin trouble experience, wearing comfort and usability showed a significant difference. As a result of the difference in satisfaction with medical masks based on demographic characteristics and side effect experience caused by wearing medical masks, breathing, ear string tightness, blocking harmful substances, price, and over all wearing comfort showed a significant difference by gender, marital status, age, occupation, and monthly income, and the presence of absence of breathing difficulty experience and skin trouble experience, respectively. As a result of the interaction effect analysis between demographic characteristics and side effects experience caused by wearing medical masks, it showed a significant interaction effect between gender and monthly income, between marital status and monthly income, between monthly income and breathing difficulties experience, and between monthly income and skin trouble experience.

A Predictive Model for Sensory Difference Tests Accounting for Sequence Effects

  • Lee, Hye-Seong
    • Food Science and Biotechnology
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    • v.17 no.5
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    • pp.1052-1059
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    • 2008
  • Sequential Sensitivity Analysis (SSA) and conditional stimulus model have been developed to describe sequence effects in difference tests and proposed to generate prediction of differences in sensitivity between various test protocols and to assist the appropriate selection of difference test. Yet, such models did not furnish a complete explanation of the relative sensitivity in 4 different versions of 3-alternative forced choice (AFC) tests where various interstimulus rinses were introduced. In the present study, the vector of the contrasts between various conditional stimuli were measured using same-different and 2-AFC and a new 16-distribution conditional stimulus model was developed by refining Lee and O'Mahony's contrast model. This new model gave superior predictions than previous models.

Tree Species Preference and Inter-specific Difference of Foraging Maneuver, Trees and Location among Four Canopy-dwelling Birds at High-elevation Temperate Deciduous Forest in Mt. Jumbongsan

  • Park, Chan-Ryul
    • Animal cells and systems
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    • v.9 no.1
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    • pp.41-46
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    • 2005
  • This study was conducted to reveal tree species preference and inter-specific difference of foraging behavior among four canopy-dwelling birds at forest dominated by Quercus mongolica, Acer pseudosieboldian and Carpinus cordata at 1,000 meters above sea level during breeding season of birds from 1995 to 1997 in Mt. Jumbongsan. Breeding birds were about 25 species and dominant birds were Erithacus cyane, Parus ater and Parus palustris. A relatively high number of bush-nesters can be a characteristic of breeding bird community at study area. Three gleaners (Tits, P. varius, P. palustris and P. ater) selectively preferred the trees irrespective of dominant tree species, whereas bark foragers (Nuthatch, Sitta europaea) utilized the dominant trees. The four birds showed significant inter-specific difference in use of foraging location, but the three tits did not show significant inter-specific difference in use of foraging maneuver and trees. Closely related tits may coexist with each other by inter-specific different use of foraging location determined by foliage structure and leaf arrangement.

Analysis on the Effect of Spectral Index Images on Improvement of Classification Accuracy of Landsat-8 OLI Image

  • Magpantay, Abraham T.;Adao, Rossana T.;Bombasi, Joferson L.;Lagman, Ace C.;Malasaga, Elisa V.;Ye, Chul-Soo
    • Korean Journal of Remote Sensing
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    • v.35 no.4
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    • pp.561-571
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    • 2019
  • In this paper, we analyze the effect of the representative spectral indices, normalized difference vegetation index (NDVI), normalized difference water index (NDWI) and normalized difference built-up index (NDBI) on classification accuracies of Landsat-8 OLI image.After creating these spectral index images, we propose five methods to select the spectral index images as classification features together with Landsat-8 OLI bands from 1 to 7. From the experiments we observed that when the spectral index image of NDVI or NDWI is used as one of the classification features together with the Landsat-8 OLI bands from 1 to 7, we can obtain higher overall accuracy and kappa coefficient than the method using only Landsat-8 OLI 7 bands. In contrast, the classification method, which selected only NDBI as classification feature together with Landsat-8 OLI 7 bands did not show the improvement in classification accuracies.