• 한국도로학회논문집
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• 제17권1호
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• pp.119-127
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• 2015

PURPOSES : Before-and-after studies of red light cameras were conducted with the aim of reducing the number of side right-angle collisions. Three different methods were used for the before-and-after studies, and the analysis results were compared. METHODS : This research used the naive before-and-after method, the comparison-group method, and the empirical Bayes method to study the effects of red light cameras on side-angle collisions. The results of the three before-and-after methods were compared and interpreted in terms of safety indications at signalized intersections. RESULTS : The research results showed that side right-angle collisions can be reduced by installing red light cameras at signalized intersections. All three methods guarantee safety improvements of 25~30% on average. With regard to the results of each method, the naive before-and-after method, the comparison-group method, and the empirical Bayes method showed safety improvements of 25.6%, 27.8%, and 29.7%, respectively. CONCLUSIONS : It was concluded that red light cameras are an effective countermeasure to improve intersection safety. In particular, by installing red light cameras, side right-angle collisions can be reduced by up to approximately 25~30%.

• 혜화의학회지
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• 제24권1호
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• pp.15-24
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• 2015

Objectives : This study was carried out to assess the risk of bias of clinical trials on acne treatment with herbal medicine that have been published in Korea. Methods : 7 electronic databases in Korea were searched for clinical trials on acne treatment. Two independent reviewers selected clinical trials on herbal medicine treatment for acne. Selected studies are categorized according to DAMI(Study Design Algorithm for Medical literature of Intervention). RCTs are assessed according to Cochrane RoB(Risk of Bias), non-randomized studies(Before-after studies) are assessed according to RoBANS(Risk of Bias Assessment tool for Non-randomized Study). Results : After selection process, 25 articles are left. Among 25 articles, 3 RCTs and 4 before-after studies are finally included. In RCTs, the proportion of 'unclear' is high in criteria of 'random sequence generation', 'allocation concealment', and 'blinding'. In before-after studies, 'high' is high in criteria of 'blinding for outcome assessment' and 'incomplete outcome data'. Conclusions : Considering the above results of the assessment, it is necessary to conduct more well designed clinical trials on acne treatment with herbal medicine.

• Journal of Preventive Medicine and Public Health
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• 제35권4호
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• pp.275-281
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• 2002

Objectives : To evaluate the DNA damage by hair dyeing in human lymphocytes Methods : Comet assays were carried out to evaluate the DNA damage in lymphocytes by hair dyeing. Twenty subjects were selected from women volunteers whose age ranged from 55 to 67 year old. All subjects had no smoking history. Blood samples were collected before and 6 hours after hair dyeing. DNA damage was evaluated by means of the tail moments, which were quantified by a KOMET 4.0 image analysis system. Results : The tail moments before hair dyeing showed no significant differences among subjects except for the high frequency group. The mean values of the tail moments in subjects with low and high frequencies of hair dyeing were 1.39 and 1.77, respectively (p<0.05). The tail moments after hair dyeing increased significantly, The mean values of tail moments in subjects before and after hair dyeing were 1.45 and 1.79, respectively (p<0.01). However, the difference levels of DNA damage in lymphocytes before and after hair dyeing were found to be slightly lower in both the dietary supplement taking group and high frequency group. Conclusions : The high frequency group appears to have a higher level of DNA damage than the low frequency group before hair dyeing. DNA damage in lymphocytes was found to be significantly higher in the volunteers after hair dyeing. In this study, the related factors such as high frequency and taking dietary supplements appeard to reduce DNA damage in lymphocytes after hair dyeing.

• 한방안이비인후피부과학회지
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• 제21권2호
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• pp.39-45
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• 2008

Objective : Skin barrier protects skin against harmful environment. Its function includes antimicrobial barrier as well as physical barrier. But there are few studies about the factors which improve skin barrier recovery after injury. The aim of this study is to investigate the factors which improve skin barrier recovery. Method : Nine hairless mice was anesthetized by inhalation and we tape stripped them. We used thermometer to know temperature one day ago, before anesthesia, before tape stripping, and after tape stripping. Vapometer was used to know transepidermal water loss before tape stripping, after tape stripping. And we used doppler flowmeter to measure blood flow before tape stripping, after tape stripping. Result : After analyzed data, we concluded that temperature was lower after anesthesia than before anesthesia and after tape stripping than before tape stripping. We could know that transepidermal water loss was lower after tape stripping than before tape stripping and more blood flowed after tape stripping. Conclusion : In our study, it was observed that temperature, transepidermal water loss, blood flow changed after tape stripping. But we thought lowered temperature was pathologic situation, more blood flow was to recover after injury. In traditional korean medicine, cold(寒) and imbalance of blood flow(血行) don't only make many skin diseases, but cold(寒) also obstructs blood flow. So we need to study how to warm cold(寒) and improve blood flow.

• Journal of Korea Trade
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• 제23권7호
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• pp.83-95
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• 2019

Purpose - This study analyzed the effect of the Trump Government's protectionist trade policies on foreign ownership. Specifically, this study empirically analyzes the hypothesis that foreign ownership will decrease after the Trump Government rather than before the Trump Government. Design/methodology - The hypothesis of this study is based on the expectation that US protection trade policy will negatively affect the profitability of Korean companies. The dependent variable in this study is the foreign ownership ratio, and the independent variable is a dummy variable representing before and after the Trump Government. Multiple regression analysis was performed, including the control variables suggested in previous studies related to foreign ownership. Findings - As a result, foreign ownership increased after the Trump Government rather than before the Trump Government. This study further analyzes whether the main variables affecting foreign investor's decision-making are differences before and after Trump Government. The export ratio, profitability and dividends did not differ before and after Trump Government. However, the level of information asymmetry decreased after the Trump Government than before the Trump Government. This suggests that US protection trade policies do not adversely affect the profitability of Korean companies. However, Korean firms are improving their information environment because US protectionist trade policies can lower profitability and negatively impact capital raising. In this regard, the foreign ownership ratio seems to differ before and after the Trump Government. Originality/value - This study contributes in that it presents data that US protectionist policies can affect Korean corporate governance. This study has implications from the short-term analysis of US protection trade policy.

• Korean Journal of Acupuncture
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• 제28권3호
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• pp.177-186
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• 2011

Objectives : The aim of this study is to review clinical trials using Qigong exercise on patients with hypertension and to assess their methodology and results. Methods : Electronic literature searches for clinical trials (randomized trial, non-randomized trial, before-after study) of Qigong exercise were performed in 21 electronic databases (5 international databases and 16 Korean databases). English, Korean or Chinese articles were included. Laboratory or animal studies were excluded. Results : A total of 11 studies met the inclusion criteria. Five randomized controlled trials, Four non-randomized trials and two before-after studies were included. Seven studies used self-developed Qigong exercise. Two studies used Guolin Qigong exercise and two studies used Qigong exercise with an anti-hypertension drug. Of the nine randomized trials or non-randomized trials, four studies used an anti-hypertension drug control and three studies used waiting list controls. Compared to baseline, a change in blood pressure after the Qigong exercise treatment was significant in all studies. However, the results effect of blood pressure between Qigong exercise and controlled trials were not consistent. Conclusions : There are low-quality clinical trials of Qigong exercise for hypertension. To evaluate the effects of Qigong exercise, more rigorous trials are warranted.

• Communications for Statistical Applications and Methods
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• 제12권2호
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• pp.381-394
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• 2005

In order to estimate the damage of orchards due' to natural disasters such as typhoon, severe rain, freezing or frost, it is necessary to estimate the number of fruit bearing before and after the damage. To estimate the fruit bearing after the damages are easily done by delegations, but it cost too high to survey every insured farm household and calculate the fruit bearing before the damage. In this article, we suggest to use a random coefficient model to predict the numbers of fruit bearing in the orchards before the damage based on the tree age and the area information.

• 아동학회지
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• 제26권4호
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• pp.113-123
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• 2005

This study compared student teachers' perceptions about teaching practices and the current state of practice teaching before and after practice teaching. Subjects were 96 students at three-year colleges in Suncheon, Jollanam-do. The survey used a questionnaire, 'kindergarten teachers' recognition of practice teaching and the current state of practice teaching,'(Woo and Choi 2004), revised for this research. Differences were observed in mean scores between before and after practice teaching(t=4.30, p<.001). In sub-areas, significant differences were observed in the role of student teachers, the contents of teaching, support system, evaluation and preliminary guidance(p<.001), but not in the evaluation of practice teaching and student teachers' attitudes(p>.05). This information should be beneficial for teachers' colleges in preparation of practice teaching programs.

• 아동학회지
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• 제19권2호
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• pp.185-200
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• 1998

This research examined the development in Korean children of the comprehension of complex sentences. The relative difficulty in comprehension of the temporal conjunctions "before" and "after" was investigated. The order of mention, contextual support, and syntactic appearance was controlled. The role of cognitive strategies and developmental changes in the comprehension of these conjunction was included in this study. Subjects were 90 preschool children between 3 and 5 years of age. The task was a sentence-picture matching problem having 3 types of sentences combining temporally with "before" or "after". The results were that developmental changes in comprehension of the temporal conjunctions "before' and "after" in Korean children depended on the order of mention, contextual support, and such syntactic factors as the position of the subject of the sentence. The importance of the consistency in the occurrence of events and the order of mention in the acquisition of complex sentences among Korean children is similar to the acquisition of complex sentences in other languages.

• 대한핵의학회지
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• 제18권2호
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• pp.39-45
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• 1984

Investigating LVF directly, quantitatively and non-invasively by MUGA helps to validate and to follow up the effectiveness of new kinds of therapy. This is performed in controlled studies comparing groups of patients as demonstrated in the case of intracoronary thrombolysis. But it is also applicable on an individual basis. Contrary to the protocol in controlled studies medication was not discontinued in our patients before and after bypass surgery. This resembles the situation under routine conditions. Therefore the number of patients with reduced LVF was rather small before and after bypass operation. But, and this in the main result of our study, implementing MUGA for follow-up under this conditions can help: 1. To find out early those patients in whom LVF deteriorates postoperatively despite adequate medication. 2. To better define whether in cases of persistent or recurrent angina there is also deterioration of LVF. By this means MUGA can significantly contribute to find out whether reangiography is necessary or not, a question which often is difficult to answer in those patients.