• 대한통합의학회지
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• 제9권3호
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• pp.87-97
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• 2021

Purpose : The purpose of this meta-analysis was to evaluate the effects of transcranial direct current stimulation on the lower extremity function of stroke patients. Methods : Domestic data were gathered from studies that conducted clinical trials associated with transcranial direct current stimulation and its impact on lower extremity function of stroke patients. A total of 592 studies published between 2012 and 2020 were identified, with 7 studies satisfying the inclusion data. The studies consisted of patient, intervention, comparison, and outcome (PICO) data. The search outcomes were items associated with muscle activity, balance, muscle strength and walking ability. Cochrane risk of bias (ROB) was used to evaluate the quality of 3 randomized control trials. The quality of 4 non-randomized control trials was evaluated using risk of bias assessment tool for non-randomized studies (RoBANS). Effect sizes in this study were computed as the corrected standard mean difference (SMD). A random-effect model was used to analyze the effect size because of the high heterogeneity among the studies. Egger's regression and 'trim-and-fill' tests were carried out to analyze the publishing bias. Results : The following factors had a large total effect size (Hedges's g=2.10, 95 %CI=1.54~2.66) involving transcranial direct current stimulation on stroke patients: muscle activity (Hedges's g=2.38, 95 %CI=1.08~3.68), balance (Hedges's g4=2.41, 95 %CI=1.33~3.60), walking ability (Hedges's g=1.54, 95 %CI=0.49~2.59), and muscle strength (Hedges's g=2.45, 95 % CI: 0.85~4.05). Egger's regression test showed that the publishing bias had statistically significant differences but 'trim-and-fill' test showed that there was still statistical difference. Conclusion : This study provides evidence for the effectiveness of transcranial direct current stimulation on the lower extremity in terms of muscle activity, balance, walking ability, and muscle strength in stroke patients. However, due to the low quality of studies and high heterogeneity factors, the results of our study should be interpreted cautiously.

• 응용통계연구
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• 제33권4호
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• pp.409-420
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• 2020

사업체조사에서는 흔히 수정절사법이 사용되며 이 방법을 사용함으로써 표본의 수를 줄이면서도 추정의 정확성을 향상 시킬 수 있다. 그러나 전수층의 무응답률은 크게 높아지고 있으며 예비표본을 이용한 표본대체가 불가능하기 때문에 전수층에서 발생한 무응답은 추정의 정확성을 크게 떨어뜨리고 있다. 특히 무응답이 관심변수에 영향을 받는 경우에는 편향이 발생할 가능성이 매우 높기 때문에 이를 적절히 처리하는 것은 매우 중요하다. 본 연구에서는 전수층에서 발생한 무응답을 적절히 처리하는 방법의 하나로 편향보정 추정법을 제안하였다. 특히 Chung과 Shin(2020)에서 제안한 편향보정 추정량을 전수층 편향보정에 적용하였으며 전수층이라는 특수한 경우에 맞는 새로운 추정 방법을 제안하였다. 또한 모의실험을 통해 제안된 방법의 우수성을 살펴보았으며 실제 자료 분석을 실시하여 본 논문에서 제안한 방법의 우수성을 확인하였다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2008년도 학술발표회 논문집
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• pp.299-303
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• 2008

In this study, an uncertainty assessment for surface air temperature(T2m) and precipitation(PCP) over East Asia is carried out. The data simulated by the intergovermental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) Atmosphere-Ocean coupled general circulation Model (AOGCM) are used to assess the uncertainty. Examination of the seasonal uncertainty of T2m and PCP variabilities shows that spring-summer cold bias and fall warm bias of T2m are found over both East Asia and the Korea peninsula. In contrast, distinctly summer dry bias and winter-spring wet bias of PCP over the Korea peninsula is found. To investigate the PCP seasonal variability over East Asia, the cyclostationary empirical orthogonal function(CSEOF) analysis is employed. The CSEOF analysis can extract physical modes (spatio-temporal patterns) and their undulation (PC time series) of PCP, showing the evolution of PCP. A comparison between spatio-temporal patterns of observed and modeled PCP anomalies shows that positive PCP anomalies located in northeastern China (north of Korea) of the multi-model ensemble(MME) cannot explain properly the contribution to summer monsoon rainfalls across Korea and Japan. The uncertainty of modeled PCP indicates that there is disagreement between observed and MME anomalies. The spatio-temporal deviation of the PCP is significantly associated with lower- and upper-level circulations. In particular, lower-level moisture transports from the warm pool of the western Pacific and corresponding moisture convergence significantly contribute to summer rainfalls. These lower- and upper-level circulations physically consistent with PCP give a insight of the reason why differences between modeled and observed PCP occur.

• 한국지반공학회논문집
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• 제28권2호
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• pp.43-55
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• 2012

본 연구에서는 연약지반개량공법의 하나인 쇄석다짐말뚝공법의 저항계수를 산정하기 위한 저항편향계수를 산정하였다. 쇄석다짐말뚝공법의 저항편향계수를 산정하기 위하여 국내외 현장에서 수행된 41개 말뚝의 재하시험 결과로부터 산출된 2.54cm 침하량기준의 극한지지력과 말뚝직경의 2~3배의 깊이에서 팽창파괴가 지배적인 파괴유형이므로 팽창파괴에 대한 7개의 극한지지력공식을 사용하여 저향편향계수를 분석한 결과 확률밀도함수는 쇄석다짐말뚝의 7개 팽창파괴에 대한 극한지지력식 모두 로그정규분포 형태를 보였고, 저항편향계수/변동계수는 Greenwood(1970) 제안식에서는 0.91/0.38, Hughes & Withers(1974) 제안식에서는 1.19/0.39로 팽창파괴에 대한 극한지지력식 중에서 저항계수설계법의 저항계수 산정 시 적합한 제안식으로 분석되었다.

• 응용통계연구
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• 제21권3호
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• pp.361-375
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• 2008

본 논문에서는 패널의 일부를 규칙적으로 교체하는 4-8-4 교체표본설계에서 발생할 수 있는 항목 무응답을 대체하는 방법에 대하여 연구하였다. 특히 소득이나 취업과 같이 민감한 질문에 대하여 발생할 수 있는 무응답에 대하여 무시할 수 없는 무응답(nonignorable nonresponse) 체계하에서 발생하는 무응답을 가정하였다. 무응답들의 대체방법으로 모형에 기반한 대체방법을 고려하였으며 베이지안 방법을 이용하여 사후확률밀도함수를 최대화하는 최대사후우도추정량(maximum posterior likelihood estimator)을 구하였다. 그리고 대체된 자료를 이용하여 면접시점이 달라질 때 발생하는 편향을 추정하였으며 추정된 편향을 제거한 후 연속적인 두 조사기간에서의 각 칸의 확률과 고정된 시점에서의 주변확률을 계산하였다. 모의실험을 통해 최종적으로 도출된 결과를 평균제곱오차와 편향의 관점에서 비교하였다.

• Journal of Acupuncture Research
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• 제32권3호
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• pp.135-146
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• 2015

Objectives : This study was designed to evaluate clinical evidence of moxibustion treatment for knee pain. Methods : All processes were independently carried out by three investigators. A literature search was performed in 3 databases from their inception to May 2015. Ten reports were found based on their title, abstract and text. Following this, data extraction and analysis were done using a risk of bias(ROB) and through an assessment of multiple systematic reviews(AMSTAR). Results : 10 studies(6RCT, 2SR, 2CR) were included. Generally, indirect moxibustion was used for knee pain, but only one study indicated the use of direct moxibustion. Moxibustion was shown to be effective in treating knee pain, and the number of required treatments was fourteen on average. In assessing risk of bias, indefinite and uncertain information made all included trials subject to a high risk of bias. On the other hand, SR showed all evaluation items in the assessment of multiple systematic reviews, with the exception of an included or excluded studies list. Conclusions : Because of deficient study design or limited research planning, there is not sufficient evidence to allow for any conclusion about the efficacy of moxibustion for knee pain. Therefore, well-designed high quality trials are needed from now on.

• 척추신경추나의학회지
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• 제11권1호
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• pp.1-10
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• 2016

Objectives : The purpose of this study was to review the effectiveness of Chuna manual therapy for the treatment of tension type headache(TTH). Methods : All processes were independently carried out by three investigators. Literature search was performed in 3 databases(pubmed, OASIS, NDSL) from their inception to May 2016. Searched reports was twice excluded for title, abstract and body. And then, data extract and analysis was done before assessing risk of bias by Cochrane Handbook. Results : 11 RCT were included. Generally, Fascia Chuna therapy and Chuna spine & joint manipulation therapy were used for TTH. Except for 1 report, Chuna manual therapy was shown to be effective in treating TTH. In assessing risk of bias, because of the characteristic of intervention, blinding of participants was high risk of bias in most reports. Conclusions : Chuna manual therapy was shown to be effective in treating TTH. In korea, better designed trials with high quality is needed from now on.

• 한국조사연구학회지:조사연구
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• 제3권2호
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• pp.47-76
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• 2002

출발점 편의는 최초입찰이 응답자의 최종입찰에 영향을 미치는 반복입찰 프레임 위에서 발생한다. 입찰게임은 가상상황 가치평가 연구에서 비시장재의 가치평가를 할 때에 가장 흔히 사용되는 방법이며 개별면접이나 전화면접의 방법으로 이루어진다. 입찰은 응답자에게 최초 입찰을 제시함으로써 시작되는데 응답자가 최초입찰을 기꺼이 지불할 용의가 있으면 부정적 응답이 나올 때까지 입찰값을 올리고 최초입찰에 부정적이었을 때는 수용할 수 있는 금액이 나올 때까지 입찰값을 낮추어 가게 된다. 최종 입찰은 응답자의 힉스적 보상 또는 가치평가 하려는 항목의 동등 잉여를 측정하는 척도로 생각된다. 본 논문에서는 입찰게임에 있어서의 출발점 편의를 실증적으로 검토하였다. 즉, 최종입찰이 최초 입찰의 크기에 의하여 영향을 받고 있는지를 서울과 그 근처에서 수돗물의 수질개선을 위한 지불 의사액을 추정하는 과정에서 입찰게임을 적용함으로써 실증적으로 검정하였다. 검정결과는 출발점 편의가 존재하는 것으로 생각되며 그 크기는 ${\delta}$=-0.265237.

• Korean Journal of Acupuncture
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• 제35권4호
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• pp.159-165
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• 2018

Objectives : This study was performed to review the efficacy of national and international randomized controlled trials (RCTs) investigating evidence on thread embedding therapy for knee osteoarthritis. Methods : Online databases (PubMed, EMBASE, Cochrane, NDSL, OASIS, CNKI) were searched for studies where thread embedding therapy was performed for Knee Osteoarthritis from their inception to July 2018. Two researchers independently performed the search. Only RCTs were selected. Eligible studies were selected first by the abstract and the title and then included after full-texts were read. Risk of bias of the included studies were evaluated using the Cochrane risk of bias assessment tool. Data were narratively summarized. Results : There were 334 studies retrieved from the databases, resulting in analysis of 3 RCTs. There was an average of 1.5 treatment visits over a 7 day period and evaluation tool used was efficacy rate, with traditional acupuncture being the most common control used in the trials. Statistically significant improvement by thread embedding therapy was reported. None of the included RCTs reported on adverse reactions. The risk of bias of the included studies was generally unclear. Conclusion : The review suggests that thread embedding therapy can be effective in knee osteoarthritis. But there was a lack of detailed information about the treatment procedures, and the risk of bias was unclear. Therefore, there is insufficient evidence for thread embedding therapy for knee osteoarthritis.

• 응용통계연구
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• 제32권4호
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• pp.631-642
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• 2019

다수의 항목무응답이 발생한 표본조사에서는 추정의 정확성이 떨어진다. 이를 해결하기 위한 많은 방법이 개발되었으나 응답률이 관심변수에 의해 영향을 받는 경우임에도 이를 고려하지 않고 랜덤으로 무응답이 발생한다는 가정 하에서 사용하는 무응답 처리 방법을 사용하게 되면 편향이 발생하는 것으로 알려져 있다. Chung과 Shin (2017)과 Min과 Shin (2018)은 응답률이 관심변수의 함수인 경우에서 발생된 편향을 적절히 처리하여 추정의 정확성을 향상시키는 방법을 제안하였다. 본 연구에서는 응답률 함수가 선형(linear)이면서 초모집단 모형의 오차가 정규분포를 따르는 경우를 살펴보았으며 층별 모집단 수가 편향 보정에 영향을 주는지도 살펴보았다. 모의실험을 통하여 제안된 추정량의 성능을 살펴보았으며 실제 자료 분석을 통해 이를 확인하였다.