• 제목/요약/키워드: Difference-in-difference

검색결과 72,262건 처리시간 0.081초

Solution to Slow Down Myopia Progression

  • Jung, Ji-Won
    • 한국임상보건과학회지
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    • 제8권1호
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    • pp.1386-1397
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    • 2020
  • Purpose: To examine the effectiveness of various treatments; bifocal spectacles, orthokeratology, atropine, and time spent in outdoors; in slowing down the myopia progression for Asian adolescents (6-18age). Methods: The research focused on examining the most effective treatment in controlling myopia based on the literature sources that have been published. Through meta-analysis of various research papers that already has been done in this field, a lot of data was collected. For each treatment, the difference in axial length and spherical equivalent over time was measured and recorded. To quantitatively record the difference, both axial length and spherical equivalent was determined by value of control group value of treatment group. The paper compared the effectiveness of each treatment based on the data that was measured. Results: Adolescents who chose to spend time outdoors in order to slow down myopia progression had axial length difference of 0.03 mm and spherical equivalent difference of 0.17 D. Adolescents that used atropine had axial length difference of 0.36 mm and spherical equivalent difference of 0.92 D. Bifocal spectacle resulted in axial length difference of 0.21 mm and spherical equivalent difference of 0.59 D, and for orthokeratology 0.23 mm and 0.04 D, respectively. Axial length wise, myopia was most controlled by the atropine since there was a greatest difference between the group that got the treatment and the group that did not have the treatment. According to the spherical equivalent difference data, myopia was most controlled by atropine. Conclusion: Atropine showed the most effective result in controlling myopia among the four treatment. Again, compared to other three treatment, using atropine appeared to have greatest ability in slowing down myopia progression since adolescents who were treated with atropine had greatest difference from adolescents in the control group that had the same condition but didn't get the treatment. However, every treatment was only used for 2 or 3 years which is quite short time period to measure the long term effect of the four treatments. Also, since atropine is a pharmaceutical method to control myopia, it may harm adolescents' eyes compared to optical or environmental treatment.

Detection of LSB Matching Revisited Using Pixel Difference Feature

  • Li, Wenxiang;Zhang, Tao;Zhu, Zhenhao;Zhang, Yan;Ping, Xin
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제7권10호
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    • pp.2514-2526
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    • 2013
  • This paper presents a detection method for least significant bit matching revisited (LSBMR) steganography. Previous research shows that the adjacent pixels of natural images are highly correlated and the value 0 appears most frequently in pixel difference. Considering that the message embedding process of LSBMR steganography has a weighted-smoothing effect on the distribution of pixel difference, the frequency of the occurrence of value 0 in pixel difference changes most significantly whereas other values approximately remain unchanged during message embedding. By analyzing the effect of LSBMR steganography on pixel difference distribution, an equation is deduced to estimate the frequency of difference value 0 using the frequencies of difference values 1 and 2. The sum of the ratio of the estimated value to the actual value as well as the ratio of the frequency of difference value 1 to difference value 0 is used as the steganalytic detector. Experimental results show that the proposed method can effectively detect LSBMR steganography and can outperform previous proposed methods.

DITI를 이용한 Bell's palsy환자의 증상 중등도 및 안면과 상지에 분포한 경혈의 관계에 대한 고찰 (Study on the Severity Measurement and the Correlation between Acupoints on the Face and the Upper limb in Bell's Palsy Patients by using of DITI)

  • 이원희;임호제;송수철;김정욱;배기태;문성일
    • Journal of Acupuncture Research
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    • 제23권5호
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    • pp.93-103
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    • 2006
  • Objectives : To Investigate Severity Measurement and the Correlation between Acupoints on the Face and the Upper limb in Bell's Palsy Patients by Using of DITI. Methods : By using of DITI, thermal differences between abnormal and normal site in acupoints on the face and the upper limbs of 21 Bell's palsy patients who visited department of Acupuncture & Moxibustion in National Medical Center from 1st February 2004 to 31th December 2005 were measured around 7days after the onset in standardized Environment. The patients were classified by severity scale. Results : The means of thermal difference of the facial acupoints were significantly distributed at each grade. The thermal difference of GB14 was significantly correlated with thermal difference of TE4, the thermal difference of S4 was significantly correlated with thermal difference of L6 and SI4, the thermal difference of STI18 was significantly correlated with thermal difference of LI11 and the thermal difference of LI20 was significantly correlated with thermal difference of LI11 and LI4. The thermal differences of acupoints in Large intestine meridian were more closely correlated with thermal difference of the facial acupoints than thermal difference of acupoints in the other meridians. Conclusion : Severity of Bell's palsy can be presumed through DITI image. And the theory of meridian was confirmed by DITI in Bell's palsy patients.

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연령별 지역별 근력 및 근지구력에 관한 연구 (The Study an Muscle Power & Muscle Endurence by Age Group and Regional Group)

  • 엄기매
    • 대한물리치료과학회지
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    • 제2권1호
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    • pp.375-381
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    • 1995
  • The purpose of this study was to investigate the muscle power and muscle endurance, situp and bend of back in age group and regional group. The mesurment of muscle power and muscle endurance was performed on 156 males and 160 fimales. The results of study were as follows. 1. Right grip showed significant difference by age group, but no significant differ ence by reginal group in male's case. 2. Left grip showed significant difference by age group but no significiant differ ence by regional group in male's case. 3. Back strength showed significant difference by age group and reginal group. 4. Sit-up showed significant difference by age group but no significant difference by regional group in male's case. 5. Bed of back showed significant difference by age group but no significant differ ence by regional group in male's case. 6. Jump showed significant difference by age group and reginal group.

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What Is the Difference between Chinese and Japanese FTAs?

  • Kang, Da-Yeon;Jeon, Young-Seo
    • Journal of Korea Trade
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    • 제24권5호
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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.

A FOURTH-ORDER ACCURATE FINITE DIFFERENCE SCHEME FOR THE EXTENDED-FISHER-KOLMOGOROV EQUATION

  • Kadri, Tlili;Omrani, Khaled
    • 대한수학회보
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    • 제55권1호
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    • pp.297-310
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    • 2018
  • In this paper, a nonlinear high-order difference scheme is proposed to solve the Extended-Fisher-Kolmogorov equation. The existence, uniqueness of difference solution and priori estimates are obtained. Furthermore, the convergence of the difference scheme is proved by utilizing the energy method to be of fourth-order in space and second-order in time in the discrete $L^{\infty}-norm$. Some numerical examples are given in order to validate the theoretical results.

성인의 활동형태와 관련된 요통발생에 관한 조사연구 (A Study on Occurrence of Backache Related to Types of Daily Activities in Adulthood)

  • 허영
    • 대한간호학회지
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    • 제8권1호
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    • pp.99-110
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    • 1978
  • For the study on occurrence of backache related to types of daily activities in adulthood Nine hundred twenty six adults living in Seoul were randomly selected as subjects from the eight kinds of occupation; housewives, teachers, nurses, officers, physicians, labourers, beauticians & barbers, and students. The purpose of this study was to identify various factors related to backache in daily activities and to apply these factors in clinical situations as well as in the community situations. This survey was conducted from September 21 through October 8, 1976. Under the ten hypothesis designed for this study, the. followings were obtained; 1. Significant difference on occurrence of backache was revealed according to sex difference at 0.5% level. (x$^2$= 27.85, df: 1, p<0.005) 2. Significant difference on occurrence of backache was revealed according to age groups at 2.5% level. (x$^2$= 11.13, df= 3, p<0.025) 3. Significant difference on occurrence of backache was revealed according to types of occupation at 2.5% level. (x$^2$= 18.04, df: 7, p<0.025) 4. Significant difference on occurrence of backache was revealed according to types of movement originated by hand during occupational activities at 1% level. (x$^2$= 14.23, df= 4, p<0.01) 5, Significant difference on occurrence of backache was revealed according to types f movement of legs during occupational activities at 0.5% level. x$^2$= 20.78, df: 3, p<0.005) . No significant difference on occurrence of backache was revealed according to length f daily working hours. . Significant difference on occurrence of backache was revealed according to degree of exercises at the level. x$^2$= 6.01, df= 2, p<0.05) . Significant difference on occurrence of backache was revealed according to sleeping posture at 1% level. x$^2$= 9.61, df: 2, p<0.01). Significant difference on occurrence of backache was revealed according to ordinary pattern of mean posture score at 0.5% level. (t : 4.27, df: 924, p<0.005) 10. Significant difference was revealed mean posture scores according to period of backache history at 0.5% level. (f- ratio = 3.73, df= 4, 562 p<0.005).

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GPS 반송파의 시각차분 특성 (Time Difference Characteristics of GPS Carrier Phase)

  • 유호;이은성;이영재;지규인;남기욱;전향식
    • 한국항공우주학회지
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    • 제33권9호
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    • pp.66-72
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    • 2005
  • GPS반송파 위상을 이용한 측위시 미지정수 결정없이 위치해를 구하는 방법 중 하나인 시각차분의 특성을 분석한다. 필요로 하는 정확도의 위치해를 구할 때, 시각차분을 이용하게 되면 차분 시간간격이 중요한 판단요소가 된다. 차분 시간간격이 클수록 정밀도는 향상되고 일정 차분간격 이후부터는 수cm의 일정한 정밀도를 유지한다고 알려져 있는데, 본 논문에서는 실제 데이터로 이러한 시각차분의 특성을 파악하고, 시각차분의 정밀도를 알 수 있는 새로운 파라미터를 제안한다. 제안된 파라미터로 위치오차가 수cm로 수렴할 때의 차분 시간간격을 추정함을 확인한다.

운율 및 분절음의 독립적 발음 평가 연구: 평가자 집단의 언어별 차이를 중심으로 (A Study of an Independent Evaluation of Prosody and Segmentals: With Reference to the Difference in the Evaluation of English Pronunciation across Subject Groups)

  • 박한상
    • 말소리와 음성과학
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    • 제5권4호
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    • pp.91-98
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    • 2013
  • This study investigates the difference in the evaluation of foreign-accentedness of English pronunciation across subject groups, evaluated accents, and compared components. This study independently evaluates the prosody and segmentals of the foreign-accented English sentences by pairwise difference rating. Using the prosody swapping technique, segmentals and prosody of the English sentences read by native speakers of American English (one male and one female) were combined with the corresponding segmentals and prosody of the English sentences read by male and female native speakers of Chinese, Japanese or Korean (one male and one female from each native language). These stimuli were evaluated by 4 different subject groups: native speakers of American English, Korean, Chinese, and Japanese. The results showed that the Japanese subject group scored higher in prosody difference than in segmental difference while the other groups scored the other way around. This study is significant in that the attitude toward the difference in segmentals and prosody of the foreign accents of English varies with the native language of the subject group. In other words, for native speakers of some languages, the difference in prosody could have a greater influence on the foreign-accentedness than the difference in segmentals, while for native speakers of other languages the other way around.

DECOMPOSITIONS OF IDEALS IN DIFFERENCE ALGEBRAS

  • AHN, SUN SHIN
    • 호남수학학술지
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    • 제28권3호
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    • pp.343-351
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    • 2006
  • In this paper, we study decompositions of weak ideals in difference algebras and obtain equivalent conditions for closed weak ideals. Moreover, we show that if I is an ideal of a difference algebra X, then $I^g$ is an ignorable weak ideal of X.

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