• 제목/요약/키워드: Difference-In-Difference

검색결과 72,815건 처리시간 0.08초

지니(Gini)의 평균차이를 이용한 산포관리도 (A Control Chart of the Deviation Based on the Gini′s Mean Difference)

  • 남호수;강중철
    • 산업경영시스템학회지
    • /
    • 제24권67호
    • /
    • pp.11-18
    • /
    • 2001
  • The efficiency and robustness of the scale estimator based on the Gini's mean difference are well known in Nam et al.(2000). In this paper we propose use of robust control limits based on the Gini's mean difference for the control of the process deviation. To compare the performances of the proposed control chart with the existing R-chart or S-chart, some Monte Carlo simulations are performed. The simulation results show that the use of the Gini's mean difference in construction of the control limits has good performance.

  • PDF

Effects of Deep Abdominal Muscle Strengthening Exercises on Pulmonary Function and the Ability to Balance in Stroke Patients

  • Kang, Jeong-Il;Kim, Beom-Ryong;Park, Seung-Kyu;Yang, Dae-Jung;Jeong, Dae-Keun;Kim, Je-Ho
    • The Journal of Korean Physical Therapy
    • /
    • 제27권4호
    • /
    • pp.258-263
    • /
    • 2015
  • Purpose: This study investigated effects of deep abdominal muscle strengthening exercises on pulmonary function and the ability to balance in stroke patients and was conducted to propose an exercise program for improving cardiovascular function. Methods: Study subjects were 20 patients with hemiplegia due to stroke, who were divided into the deep abdominal muscle strengthening exercise group (experimental group), 10, and the control group, 10. Pulmonary function tests measured FVC and FEV1, dynamic balance ability was measured using TUG. Static and dynamic balance ability was measured using BBS. The experimental group performed exercises during a period of 6 weeks, 5 times a week for 40 minutes, whereas the control group did not participate in regular exercise. The difference before and after the exercise was compared using paired t-test, difference in exercise before and after between groups was ANCOVA and level of significance was set at ${\alpha}=0.05$. Results: The changes in FVC and FEV1 within the group showed a significant difference only in the experimental group (p<0.001) (p<0.01), between-group difference was statistically significant only in FVC and FEV1 changes in the experimental group (p<0.001). The TUG changes within the group showed a significant difference in the experimental group and control group (p<0.001) (p<0.05), while BBS changes showed a significant difference only in the experimental group. Between-group difference was statistically significant only in TUG and BBS changes in the experimental group. The experimental group showed a more effective significant difference than the control group (p<0.001). Conclusion: Can exercise involving a deep abdominal muscle strengthening program be applied in patients with stroke with difficulty in control of trunk and decreased breathing ability?

차균형성질을 갖는 d-동차함수로부터 생성된 새로운 순회상대차집합 (New Cyclic Relative Difference Sets Constructed from d-Homogeneous Functions with Difference-balanced Property)

  • 김상효;노종선
    • 정보보호학회논문지
    • /
    • 제12권2호
    • /
    • pp.11-20
    • /
    • 2002
  • 본 논문에서는 q는 p의 멱승이고, $F_{q^{n}}$이 원소의 개수가 $q^{n}$ 개인 유한체라 할 때, $F_{q^{n}}${0}으로부터의 $F_{q}$ 로의 차균형 성질을 갖는 d-동차함수로부터 (equation omitted) 순회상대차집합이 얻어질 수 있음을 보인다. 이에 따라 주기가 $q^{n}$ -1이고, 이상적인 자기상관성질을 갖는 p진 시퀀스 Helleseth-Gong 시퀀스 및, d-형 시퀀스로부터 (equation omitted)의 파라미터를 갖는 새로운 순회상대차집합을 생성시킨다.

BC유의 국제벙커링과 수출 가격 차이에 대한 실증 분석 (An Empirical Analysis on the Price Difference between International Bunkering and Export for Bunker-C)

  • 김영덕;한현옥
    • 자원ㆍ환경경제연구
    • /
    • 제16권2호
    • /
    • pp.239-273
    • /
    • 2007
  • 해외 판매 BC유의 국제벙커링과 수출의 경우에는 거의 유사한 품질에도 불구하고 서로 다른 가격으로 판매되고 있으며, 이 두 시장에서의 가격 차이는 2002년 이후에 크게 확대되는 모습을 보이고 있다. 실증 분석을 통하여 한국에서의 벙커링 가격과 수출 가격의 차이가 2002년 6월을 기점으로 구조적인 변화가 발생하였을 가능성이 있으며, 2002년 6월까지는 두 가격의 차이를 설명하지 못하였던 싱가포르에서의 벙커링과 연료유 가격 차이가 2002년 7월부터는 한국에서 두 가격의 차이를 설명하는 요인으로 나타나고 있음을 확인하였다. 또한, 미래 유가 상승을 기대하게 하는 전기 시차의 국제 원유가격의 상승률도 한국에서 벙커링과 수출 가격의 차이를 설명하는 요인임을 알 수 있었다. 이러한 추정 결과는 한국에서의 국제벙커링과 수출의 가격 차이가 가격차별에 의해서 설명될 가능성을 배제하지는 않는 결과이다.

  • PDF

연령에 따른 보행의 시간적·공간적 요소에 관한 연구 (Research for Temporal·Spatial Parameter of the Gait According to Age)

  • 채정병;공승환;김동재;김라진;김태영;이승후
    • PNF and Movement
    • /
    • 제6권2호
    • /
    • pp.19-30
    • /
    • 2008
  • Purpose : This study was performed for find out temporal spatial parameter of the gait according to age. Method : Four groups of healthy people were allocated randomly in this study : group I(little child, 15), group II(child, 18) and group III(young people, 17), group(elder people, 16). This study was performed from 01 December to 31 December in 2007. Results : The results were as follows : 1. The swing phase was the longest group II, group IV was the shortest. Each groups, there was significant difference in swing phase(p<.05). 2. The stance phase was the longest group IV, group II was the shortest. Each groups, there was significant difference in stance phase(p<.05). 3. The single support time was the longest group II, group IV was the shortest. Each groups, there was significant difference in single support time(p<.05). 4. The double support time was the longest group IV, group II was the shortest. Each groups, there was significant difference in double support time(p<.05). 5. The gait velocity was the fastest group II, group I was the slowest. Each groups, there was significant difference in gait velocity(p<.05). 6. The toe in/out was very increased group IV, group I was very decreased. Each groups, there was significant difference in toe in/out(p<.05). 7. The cadence was the highest group I, group IV was the lowest. Each groups, there was significant difference in cadence(p<.05). 8. The step length was the longest group III, group I was the shortest. Each groups, there was significant difference in step length(p<.05). 9. The step length asymmetry ratio was the highest group IV, group III was the lowest. Each groups, there was no significant difference in step length asymmetry ratio(p>.05). 10. The single support time asymmetry ratio was the highest group I, group IV was the lowest. Each groups, there was no significant difference in single support time asymmetry ratio (p>.05). 11. The FAP was the highest group III, group I was the lowest. Each groups, there was significant difference in FAP(p<.05).

  • PDF

부위별(部位別) 녹용(鹿茸)이 흑색종(黑色腫) 유발(誘發) 생쥐의 종양억제(腫瘍抑制)와 면역기능(免疫機能)에 미치는 영향(影響) (Effects of Partial Cervus elaphus Linne' Extract on Antitumoral Immune Response in Melanoma-induced Mice)

  • 오하석;김장현
    • 대한한방소아과학회지
    • /
    • 제14권1호
    • /
    • pp.39-78
    • /
    • 2000
  • Introduction: In order to investigate the effects of partial Cervus elaphus Linne' extract on antitumoral immunological, a group of mice are melanoma-induced and observed reponses in terms of the number of lymphocyte, CD4+ count, CD8+ count, CD4+/CD8+ ratio in blood and spleen, change in body weight, melanoma weight, spleen index, NK cell activity and productivity of IL-2 in each mouse Methodology: Male C57BL/6 mice were chosen as an experimental object and were divided into 5 groups randomly selection. The normal group did not receive any induction. The control group was treated with normal saline in melanoma-induced' mice. Sample I group induced the upper part of Cervus elaphus Linne' extract in melanoma-induced mice. Sample II group was induced the middle part of Cervus elaphus Linne' extract in melanoma-induced mice. Sample III group was induced the lower part of Cervus elaphus Linne' extract in melanoma-induced mice. The dosage of medication was 0.2cc daily for 14days. Results: 1. There was a significant difference in the number of lymphocyte in spleen in the sample I (upper part of Cervus elaphus Linne' extract induced) and the sample II (middle part of Cervus elaphus Linne' extract induced) compared to the control group and the sample III (lower part of Cervus elaphus Linne' extract induced). On the other hand, no significant difference was observed in the number of lymphocyte in blood in the control group and all sample groups. 2. In the CD4+ T cell ratio in blood, all three sample groups showed differences compared to the control group, though there was no significant difference between sample groups. In the CD4+ T cell ratio in spleen, there was a difference between the sample I and the control group, while the sample II and the sample III had significant difference to the control group. And also, it has been observed there were differences between the sample I and the other samples. 3. In the CD8+ T cell ratio in spleen, all three sample groups showed significant differences compared to the control group, while there was no difference between groups in the ratio in blood. 4. In the CD4+/CD8+ T cell ratio in blood, the sample I showed a significant difference compared to the control group, while the sample 1I and sample III showed differences compared to the control group. In the CD4+/CD8+ T cell ratio in spleen, all three samples showed a significant difference compared to the control group, when the sample I had a difference to the other sample groups. 5. The spleen index of the sample I and the sample II showed a significant difference compared to the sample III and the control group. In comparison between the sample groups, the sample I and the sample II showed a significant difference to the sample III. 6. In terms of the change in body weight and melanoma weight, all three sample groups showed a significant difference compared to the control group, while the comparison between the sample groups showed the sample and the sample II had a significant difference to the sample Ⅲ. 7. In comparison of NK cell activity, the sample I had a difference compared to the other groups when the effector to target cell ratio was 2.5:1. With the ratio of 5:1, the sample I and sample II showed significant differences compared to the control group, while the sample Ⅲ showed a difference. When the effector to target cell ratio was 10:1, there was no difference between groups. 8. In the productivity of IL-2, all three sample groups showed significant differences compared to the control group. In comparison between sample groups, there were significant differences between each sample groups in order of the sample I , the sample II and the sample Ⅲ. Conclusion: As one can witness from the above results, administration of partial Cervus elaphus Linne extract played important role in antitumoral immune response in melanoma-induced mice, and it could be suggested that sample I and sample II groups have prominent antitumoral immune effect.

  • PDF

편마비 환자의 슬건근의 근력의 차이가 보행에 미치는 영향 (The Influenc on Ambulation of the Difference in Muscle Strength on Hamstring Muscle of Hemiplegic Patients)

  • 윤장순
    • 대한물리치료과학회지
    • /
    • 제12권4호
    • /
    • pp.69-77
    • /
    • 2005
  • The purpose of this study is to estimate how much the motility of affected and unaffected lower limb respectively would have effects on their ambulation through comparing the difference between their affected and unaffected lower limb and studying the correlation between such difference and their ambulation. In addition, the study also intends to find out remedial measures suitable for improving their ambulation with relevant physical treatment. To do this, a quantitative electromyogram(QEMG) test was done to hamstring of affected and unaffected lower limb so as to yield IP values. Based on such IP values, RMS(root mean square) values as the total sum of IP values were found with QEMG analysis system (made by Medelec Co.) and then the ambulation depending on the difference in muscular strength were analyzed by ink-foot print method as well as the corresponding statistics were processed by T-test through SPSS. The differences in muscular strength of hamstring in unaffected limbs of hemiplegic patients only affect stride length. It was statistically significant. The effect of difference in muscular strength of the hamstring in affected limb of hemiplegic patients on their ambulation was very different between strong and weak group in terms of walking velocity, step per minute, stride and step length, showing statistically significant difference(p<.05). Although there was a difference in the step length of the affected limb, it was not statistically significant(p>.05). For the unaffected hamstring, there were significant differences of stride length between in unaffected limb and in affected limb. For the affected hamstring, there were also significant differences in walking velocity, step per minute, stride and step length. Besides, it was found that the difference of the muscular strength between strong and weak group was at the highest.

  • PDF

"Standard Model" approach to building projects in the UK and potential role of project team to mitigate any local difference~from international developer's perspective

  • Tanaka, Koji
    • 국제학술발표논문집
    • /
    • The 8th International Conference on Construction Engineering and Project Management
    • /
    • pp.425-432
    • /
    • 2020
  • In order to improve the sustainability and smart construction, it is discussed arguably that developing and applying consistent "standard model" to plan business, design, construct and operate a building is considered to be one of the effective and efficient approach. The scope of this article is to examine, from the international developer's perspective, the "standard model" approach of a hotel brand to building projects in the UK, and also to explore potential role of project team to mitigate any local difference at the project level. These projects are developed by the same developer adopting the same business plan, design and operation to each project. In order to clarify the actual and likely difference in construction results, reference is also made to those building projects located in other geographical markets including Japan, Germany and USA, and focus is given on the analysis of its programme and cost. Principle findings are that there exists geographical difference especially in environmental and planning system, and that major local difference is found at least in the programme at the design stage. In contrast, the difference in the building cost itself may not be necessarily considered major if currency exchange rate being taken into account appropriately. It is also observed that there were cases where any difference in the programme was mitigated by taking different approach to procuring and defining roles of management and professional team at the project level. In conclusion, from the international developer's perspective, the geographical difference of the "construction system" surrounding building projects can typically lead to major prolongation of programme, however, these different construction results could be mitigated at least to a certain extent by introducing appropriate changes to the role of project team.

  • PDF

Low Contrast and Low kV CTA Before Transcatheter Aortic Valve Replacement: A Systematic Review

  • Spencer C. Lacy;Mina M. Benjamin;Mohammed Osman;Mushabbar A. Syed;Menhel Kinno
    • Journal of Cardiovascular Imaging
    • /
    • 제31권2호
    • /
    • pp.108-115
    • /
    • 2023
  • BACKGROUND: Minimizing contrast dose and radiation exposure while maintaining image quality during computed tomography angiography (CTA) for transcatheter aortic valve replacement (TAVR) is desirable, but not well established. This systematic review compares image quality for low contrast and low kV CTA versus conventional CTA in patients with aortic stenosis undergoing TAVR planning. METHODS: We performed a systematic literature review to identify clinical studies comparing imaging strategies for patients with aortic stenosis undergoing TAVR planning. The primary outcomes of image quality as assessed by the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were reported as random effects mean difference with 95% confidence interval (CI). RESULTS: We included 6 studies reporting on 353 patients. There was no difference in cardiac SNR (mean difference, -1.42; 95% CI, -5.71 to 2.88; p = 0.52), cardiac CNR (mean difference, -3.83; 95% CI, -9.98 to 2.32; p = 0.22), aortic SNR (mean difference, -0.23; 95% CI, -7.83 to 7.37; p = 0.95), aortic CNR (mean difference, -3.95; 95% CI, -12.03 to 4.13; p = 0.34), and ileofemoral SNR (mean difference, -6.09; 95% CI, -13.80 to 1.62; p = 0.12) between the low dose and conventional protocols. There was a difference in ileofemoral CNR between the low dose and conventional protocols with a mean difference of -9.26 (95% CI, -15.06 to -3.46; p = 0.002). Overall, subjective image quality was similar between the 2 protocols. CONCLUSIONS: This systematic review suggests that low contrast and low kV CTA for TAVR planning provides similar image quality to conventional CTA.

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

  • 이미영
    • 한국생활과학회지
    • /
    • 제21권2호
    • /
    • pp.349-362
    • /
    • 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.