• Title/Summary/Keyword: difference-in-differences method

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An Experimental Study on the Bond Strength after Surface Treatment of Non-precious Metal Alloy for porcelain Crown (도재용 비금속합금의 표면처리에 따른 결합강도에 관한 실험적 연구)

  • So, Myung-Sub
    • Journal of Technologic Dentistry
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    • v.9 no.1
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    • pp.39-49
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    • 1987
  • This study done to evaluate some surface treatment methods in metal coping which can increase the bond strength between porcelain and metal. Therefore this experiment was performed according to the Mc Lean's Theory of bond strength between porcelain and strength between porcelain and metal. In the experiment the author measured respective thermal expansion coefficents in three types of metal(Tallasium, Vera Bond and Rexillium) and Vita Porcelain to get the differences in the coefficents between porcelain and metals. And using insteron testing machine, the author also performed Planar interface shear bond tests on the 45 specimens(15 specimens in oxide surface, rough surface and fine surface treatment methods respectively) to measure bond strength between metal and porcelain. The results Were as follows, 1. The differences in thermal expansion coefficients between three types of metal and Vita procelain: Talladium - $1.2\;10^{-6/0}\;C$, Vera Bond - $1.6\;10^{-6/0}\;C$, Rexillium - $1.9\;10^{-6/0}\;C$. 2. The bond strength in oxide surface on the Shear bond test was the lowest among the treatment methods. 3. There was no significant differences in treatment methods of rough surface of fine surface. 4. In the oxide surface treatment method, there were significant differences(P<0.05)between Vera bond and Rexillium, and between Talladium and Rexillium. 5. In the fine surface treatment, there was a significant difference(P<0.05)between Talladium and Rexillium.

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A Comparative Study of Blood Pressure According to Cuff Size and Measurement Site (커프크기와 측정부위에 따른 혈압측정치 비교 연구)

  • Song, Mi-Ryeong;Kim, Eun-Kyung
    • Journal of Korean Academy of Fundamentals of Nursing
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    • v.16 no.1
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    • pp.6-13
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    • 2009
  • Purpose: The purpose of this study was to identify differences in blood pressure according to cuff size and measurement sites of the participants. Method: The participants consisted of 50 women and 50 men whose upper arm circumference was $26\sim30cm$. They had no chronic illness and gave consent to participate. Blood pressure of the wrist was measured in the sitting position, the upper arm with a standard cuff, large and small cuffs were used for measurement in supine position and the thigh in prone position. The data were analyzed with paired t-test using SPSS 12.0 program. Result: The data for the upper arm showed a difference in systolic and diastolic blood pressure depending on the site of measurement. There was a significant difference between measurements with a standard cuff and measurements with large and small cuffs. The systolic blood pressure of the wrist and the thigh were significantly lower than that of the upper arm. Conclusion: These results suggest that the selection of an appropriate cuff is an essential element in ensuring accuracy when measuring blood pressure and differences in systolic blood pressure for the upper arm, wrist and thigh indicate the need to record the measuring site when measuring blood pressure.

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Effects of Disinfection According to Durations of Surgical Hand Scrub and Type of Disinfectant (외과적 손씻기 시간과 소독제에 따른 소독효과)

  • Park, Jong-Nam;Lee, Mi-Aie
    • Journal of Korean Academy of Fundamentals of Nursing
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    • v.13 no.2
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    • pp.208-216
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    • 2006
  • Purpose: This study was done to identify the differences in effectiveness of disinfections for surgical hand scrubbing according to the duration of scrubbing and the type of disinfectant. Method: From June 30 to August 14, 2003, the data were collected from 30 surgical nurses and surgeons in one general hospital in P city, Korea. All participants washed their hands with two different disinfectants and four different scrubbing times, they placed both finger tips on a blood agar plate and using sterile cotton tips microbes were collected from their palms, nails and forearms. Results: The first hypothesis of this study(with same disinfectant, there will be no difference in effect of disinfection in surgical hand scrub among four time groups) was supported. The second hypothesis of this study(with same duration of surgical hand scrub, there will be no difference in effect between two disinfectants) was also supported. Conclusion: There are no differences in effectiveness of disinfection for surgical hand scrubbing according to duration of the scrubbing and the type of disinfectant. So it is concluded that the effectiveness of disinfection depends more on the exactly how the scrubbing is done rather than the duration of scrubbing or the type of disinfectant.

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Differences in Awareness and Ethical Attitudes about Do-Not-Resuscitate among Emergency Departments' Team (심폐소생술 금지에 대한 응급의료종사자간 인식과 윤리적 태도의 차이)

  • Park, Hak-Young;Sung, Mi-Hae
    • Journal of Korean Academy of Fundamentals of Nursing
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    • v.18 no.3
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    • pp.411-420
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    • 2011
  • Purpose: The aim of this study was to exam differences in awareness and ethical attitudes associated with Do-Not- Resuscitate (DNR) among emergency department's team. Method: The participants in this study were 402 emergency department's team working in the 41 hospitals. The data was collected by using "awareness measuring tool" by Kang (2003) and "ethical attitudes measuring tool" by Ko (2004) from May 1 to September 15, 2009. Collected data were analyzed by descriptive statistics, t-test, Pearson correlation coefficient using SPSS WIN 14.0 program. Results: 74.4% of subjects was responded that they had never been educated about DNR, but 73.9% of subjects was responded that they had experienced DNR in the emergency room. The majority of subjects responded that the patients and their families should make a decision about the DNR. There was a difference in an appropriate time for explanation of DNR among emergency department's team. There was a difference in ethical attitudes associated with Do-Not- Resuscitate among emergency department's team. Conclusion: For a professional and systematic approach to the problem, DNR guideline sufficient to elicit a social consensus is needed.

Socioeconomic Predictors of Diabetes Mortality in Japan: An Ecological Study Using Municipality-specific Data

  • Okui, Tasuku
    • Journal of Preventive Medicine and Public Health
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    • v.54 no.5
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    • pp.352-359
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    • 2021
  • Objectives: The aim of this study was to examine the geographic distribution of diabetes mortality in Japan and identify socioeconomic factors affecting differences in municipality-specific diabetes mortality. Methods: Diabetes mortality data by year and municipality from 2013 to 2017 were extracted from Japanese Vital Statistics, and the socioeconomic characteristics of municipalities were obtained from government statistics. We calculated the standardized mortality ratio (SMR) of diabetes for each municipality using the empirical Bayes method and represented geographic differences in SMRs in a map of Japan. Multiple linear regression was conducted to identify the socioeconomic factors affecting differences in SMR. Statistically significant socioeconomic factors were further assessed by calculating the relative risk of mortality of quintiles of municipalities classified according to the degree of each socioeconomic factor using Poisson regression analysis. Results: The geographic distribution of diabetes mortality differed by gender. Of the municipality-specific socioeconomic factors, high rates of single-person households and unemployment and a high number of hospital beds were associated with a high SMR for men. High rates of fatherless households and blue-collar workers were associated with a high SMR for women, while high taxable income per-capita income and total population were associated with low SMR for women. Quintile analysis revealed a complex relationship between taxable income and mortality for women. The mortality risk of quintiles with the highest and lowest taxable per-capita income was significantly lower than that of the middle-income quintile. Conclusions: Socioeconomic factors of municipalities in Japan were found to affect geographic differences in diabetes mortality.

Direction Finding Method of the Uniform Circular Array Antenna Using the Pattern of Phase Differences (원형배열 안테나의 위상차 패턴을 이용한 방향탐지 기법)

  • Lim, Joong-Soo
    • Journal of the Korea Convergence Society
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    • v.10 no.1
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    • pp.1-6
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    • 2019
  • In this paper, we have studied a direction finding method of the radio signal by comparing the phase difference and its pattern from the uniform circular array antenna. In the phase comparison direction finding, if the length of the antenna baseline is longer than 0.5 wavelength of the incident signal, azimuth ambiguity occurs in which two or more azimuth angles are calculated in the same phase difference. The azimuthal ambiguity is removed by fusing the phase difference of the 5 antennas. The developed ambiguity elimination technology reduces the azimuth error where the antenna baseline is shorter than 1.236 wavelength in the uniform circular array with five antennas. This algorithm is very useful for the design of direction finder of an electronic information system.

A study on the analysis of performance differences according to the operation method of public sewage treatment facility (공공하수처리시설 운영방식에 따른 성과 차이 분석에 관한 연구)

  • Ko, Hyunsoo;Ha, Donggyun
    • Journal of Korea Water Resources Association
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    • v.55 no.5
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    • pp.357-370
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    • 2022
  • This study aims to analyze the differences in performance according to various operation methods (direct management, public consignment, and private agency) of public sewage treatment facilities and derive the most efficient and high level of sewage treatment services to the public based on the research results. To this end, economic performance indicators (sewage treatment cost, sewerage rate) and social performance indicators (water quality, number of civil complaints) were selected, and cross-sectional analysis and longitudinal analysis were used to verify the difference between the averages of three or more groups through one-way ANOVA. As a result of the analysis, cross-sectional analysis, there was no difference in economic performance dimension according to the operating method, but in terms of social performance dimension, it was found that there was a difference according to the operating method. In the case of water quality indicators, the results were superior to those directly managed by public consignment and private agencies in the number of civil complaints. In the longitudinal analysis examining the improvement of performance indicators, there was no significant difference by operation method in most performance indicators. In order to improve the efficiency of public services and improve the service level, various approaches suitable for the characteristics of each service are required in addition to the logic of public consignment or introduction of private agency. In the future, when local governments promote public consignment or private agency, it is necessary to understand and promote the nature of the service, the specificity of each local government, and the needs of service users.

Three-dimensional Kinematics of Knee Joint in a Complete Gait Cycle: A Comparative Study between Handball Players and Non-athletes

  • Dinesh, Paudel;Back, Jin-Ho
    • Korean Journal of Applied Biomechanics
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    • v.31 no.3
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    • pp.176-182
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    • 2021
  • Objective: The purpose of this study is to investigate whether the athletic knee show greater rotation and translation movement than non-athletic knee during the treadmill walking with their preferred speed in a complete gait cycle. Method: Thirty young and healthy male subjects participated in the study, fifteen handball players (mean age: 19.6 ± 1.4 years old, mean weight: 85 ± 11.9 Kg, mean height: 179.8 ± 4.7) and fifteen non-athletes (mean age: 22.8 ± 1.2 years old, mean weight: 74.5 ± 8.6 Kg, mean height: 175 ± 5.9). Three-dimensional positional coordinate of lower limb during treadmill walking were analyzed. Results: There were significant differences (t (22.014)=1.585, p=0.127 in the range of internal and external rotation with mean value for handball player (M=14.4513, SD=2.3839) was higher than non-athletes (M=13.3327, SD=1.337). The magnitude of the difference in the means (mean difference=1.11867, 95% CI: -0.34489 to 2.5822) was significant. There were also significant differences (t (17.956)=1.654, p=0.116 in the max abduction and adduction with mean value for handball player (M=5.7160, SD=2.49281) was higher than non-athletes (M=4.5773, SD=0.94667). The magnitude of the difference in the means (mean difference=1.138, 95% CI: -0.30805 to 2.58539) was significant. At significance level 0.05. Conclusion: Finding of this study suggest that to understand the actual characteristic of knee motion studies have to be done in different walking and running trial at variable speed.

Comparison of Substructure Synthesis Methods based on Global and Local Coordinates (전역좌표계에 근거한 부분구조합성법과 국부좌표계에 근거한 부분구조합성법의 비교)

  • Kwak, Moon-K.;Na, Sung-Soo;Bae, Byung-Chan
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.16 no.7 s.112
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    • pp.712-719
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    • 2006
  • This paper is concerned with the comparison of substructure synthesis methods based on global and local coordinates. The substructure synthesis methods based on the global coordinates were first proposed for the dynamic analysis of complex structure and the substructure synthesis method based on the local coordinates was proposed to solve the dynamic problem of tree-like structure. However, the conceptual difference between two methods in solving the dynamic problem has never been explained. In this paper, a structure consisting of two beams is considered to show the conceptual difference of two methods. The dynamic formulation shows the characteristics and differences of two methods explicitly. The procedure for choosing proper substructure modes in each method is also explained in detail. In addition, the advantage of the substructure synthesis method based on the local coordinate system is discussed based on the numerical example. Numerical examples show how two methods are applied to the addressed problem.

CUBE Filtering of Multibeam Echo Sounder Data (다중 빔 음향측심 자료의 CUBE 필터링)

  • Kim, Joo-Youn;Lee, Gwang-Soo;Kim, Dae-Choul;Seo, Young-Kyo;Yi, Hi-Il
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.44 no.3
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    • pp.308-317
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    • 2011
  • A MBES (multibeam echo sounder) survey around Yokji Island, Korea, was conducted to find an effective method for removing error data. Two post-processing software programs, PDS2000 (RESON) and HIPS (CARIS), were used to remove the error data using an interactive editing method and the CUBE algorithm filter. The post-processing with the PDS2000 and HIPS programs, using the interactive editing method, took 120 and 168 hours, respectively, and there was little difference in the seafloor images. The processing time of the PDS2000 and HIPS programs using the CUBE algorithm filter was 36 and 60 hours, respectively. Nevertheless, there was little difference in the seafloor images because of differences in the factor parameters in each of the post-processing programs. Therefore, post-processing using CUBE filtering can save time in data processing and provide consistent results, excluding the subjective decisions of the operator. This method is more effective than other methods for rejecting erroneous multibeam echo sounder data.