• 한국도로학회논문집
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• 제18권5호
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• pp.95-103
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• 2016

PURPOSES : Permitted left turn is a turning maneuver in which a vehicle turns left using a gap between oncoming vehicles, called gap acceptance, and it enables for more efficient traffic operation at intersections. In Korea, the permitted left turn has not been a common maneuver at signalized or un-signalized intersections. However, many experts and the Police Agency tried to apply this effective turning maneuver at intersections in Korea since 2010. Though the investigation of gap acceptance is significantly important in understanding a driver's behavior at intersections, there have not been many studies about this topic, specifically a study to develop probability models of gap acceptance behavior. METHODS : In this study, the probability model of gap acceptance behavior for a permitted left turn was developed based on observational field studies. To develop the model, seven variables were analyzed including gap, waiting time, traffic volume, conflict-flow vehicle type, left-turning vehicle type, the number of lane, and time. RESULTS : In the final model, gap and left-turning vehicle type were found to be significant influencing factors. CONCLUSIONS : Through this model development, it was concluded that as the gap size increased, the probability of gap acceptance was higher. Moreover, when a left-turning vehicle was a passenger car, the probability of gap acceptance was higher than compared to large size buses or freight cars.

• 천문학회보
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• 제39권2호
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• pp.89-89
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• 2014

While the current consensus view holds that galaxy mergers are commonplace, it is sometimes speculated that Globular Clusters (GCs) may also have undergone merging events, possibly resulting in massive objects with a strong metallicity spread such as Omega Centauri. Galaxies are mostly far, unresolved systems whose mergers are most likely wet, resulting in observational as well as modeling difficulties, but GCs are resolved into stars that can be used as discrete dynamical tracers, and their mergers might have been dry, therefore easily simulated with an N-body code. It is however difficult to determine the observational parameters best suited to reveal a history of merging based on the positions and kinematics of GC stars, if evidence of merging is at all observable. To overcome this difficulty, we investigate the applicability of supervised and unsupervised machine learning to the automatic reconstruction of the dynamical history of a stellar system. In particular we test whether statistical clustering methods can classify simulated systems into monolithic versus merger products. We run direct N-body simulations of two identical King-model clusters undergoing a head-on collision resulting in a merged system, and other simulations of isolated King models with the same total number of particles as the merged system. After several relaxation times elapse, we extract a sample of snapshots of the sky-projected positions of particles from each simulation at different dynamical times, and we run a variety of clustering and classification algorithms to classify the snapshots into two subsets in a relevant feature space.

• 한방재활의학과학회지
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• 제30권3호
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• pp.141-149
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• 2020

Objectives The purpose of this study is to find the effect of Korean medicine treatments on pain reduction and range of motion recovery in patients with proximal tibia fractures. Methods We studied 15 patients who had been diagnosed as proximal tibia fracture. This study was conducted as retrospective observational study which analyzed patient's medical records with IBM SPSS statistics 25 program. We used numeric rating scale to evaluate pain reduction and range of motion to observe the patient's recovery. Results The average of numeric rating scale reduced statistically significantly from 5.26±1.38 to 2.73±1.17 (p<0.001). The average of knee flexion range of motion increased statistically significantly from 81.11±34.34 to 117.66±19.01 (p<0.01). Conclusions We found that Korean medicine treatments have a positive effect on pain reduction and knee rom improvement in patients with proximal tibia fractures.

• Asian Pacific Journal of Cancer Prevention
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• 제14권8호
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• pp.4733-4737
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• 2013

Purpose: Numerous observational epidemiological studies have evaluated associations between breastfeeding and the risk of childhood Hodgkin lymphoma; however, the existing results are inconsistent. We therefore conducted a systematic review and meta-analysis. Methods: Medical literature was searched in the Pubmed and Embase databases to identify all English-language relevant studies up to April 10, 2013. Reference lists were thereafter hand-searched for additional articles. Studies that reported relative risk ratios (RRs) or odds ratios (ORs) with 95% confidence intervals (CIs) were included. This meta-analysis was conducted in accordance with the guidelines for the meta-analysis of observational studies in epidemiology. Results: We finally included 10 case-control studies in our meta-analysis, involving 1,618 childhood Hodgkin lymphoma cases and 8,181 controls. Overall, we did found a borderline significant association between breastfeeding and reduced risk of childhood Hodgkin lymphoma comparing ever breastfed children to never breastfed children (pooled OR =0.79; 95%CI, 0.58-1.08; P=0.13), with limited evidence for between-study heterogeneity (P =0.12, $I^2$ = 35.70%). Conclusion: There is limited evidence for an inverse association between breastfeeding and risk of childhood Hodgkin lymphoma.

• Asian Pacific Journal of Cancer Prevention
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• 제13권10호
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• pp.4927-4930
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• 2012

Background: Many observational studies have assessed the possible association between occupational cooking and uveal melanoma risk, but reported results are controversial. Our goal was to evaluate the association between occupational cooking and uveal melanoma risk by conducting a meta-analysis of observational studies. Methods: PubMed, EMBASE, and Web of Science were searched through June 2012 to identify all eligible studies. The pooled odds ratio (OR) with its 95% confidence interval (95%CI) was used to evaluate this association. Either a fixed- or a random-effects model were used to calculate pooled ORs. Results: Five case-control studies involving a total of 1,199 cases and 6,927 controls were included in the meta-analysis. Overall, occupational cooking was associated with an increased risk of uveal melanoma (OR: 1.81, 95%CI 1.33-2.46, P < 0.001). Subgroup analysis by gender suggested occupational cooking was associated with increased risk of uveal melanoma in both men (OR: 2.16, 95%CI 1.06-4.40, P = 0.034) and women (OR: 1.92, 95%CI 1.19-3.10, P = 0.008). Conclusion: This meta-analysis suggests that occupational cooking is associated with an increased risk of uveal melanoma in both men and women.

• 한국조사연구학회지:조사연구
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• 제10권1호
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• pp.169-186
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• 2009

본 연구는 사회조사에서 무응답으로 인한 편향을 축소하는 방안으로 성향점수를 이용하는 방법과 사례를 설명하기 위해서 성향점수 방법의 이론적인 개념과 배경을 정리하였다. 또한 성향점수 방법을 처음으로 적용한 역학적인 관찰연구에서 성향점수 모형의 정의와 이론적 배경을 살펴보았고 추정에서 편향의 축소방법으로 이용되는 가지 성향점수 방법을 정리하였다. 성향점수로 짝짓기는 통제그룹의 데이터가 상대적으로 많을 경우에 이용되고 부차분류법은 통제그룹의 모든 데이터를 이용할 수 있으며 회귀모형을 이용한 보정은 다중공변량에서도 사용할 수 있을 뿐만 아니라 각 관찰단위에 성향점수 값을 산출하여 사용할 수 있는 특징이 있다. 그리고 사회여론조사에서 항목무응답으로 인한 편향을 축소하는 데 성향점수 가중법을 적용하는 절차를 제안하고 기존의 데이터를 이용하여 실제 적용에 대한 가능성을 검토하였다.

• 천문학논총
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• 제27권3호
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• pp.61-69
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• 2012

The Ganui (簡儀, simplified armillary sphere) is a representative of astronomical instruments in Joseon Dynasty of Korea, as well as Yuan Dynasty and Ming Dynasty of China. In early 15th century, Joseon's scientists and engineers uniquely developed the Soganui (小簡儀, small simplified armillary sphere) and the Ilseongjeongsiui (日星定時儀, sun-and-star time determining instrument) from the structural characteristic of Ganui. These two astronomical instruments had a new design by the miniaturization and felt convinced a similar performance of Ganui in the harmony with Korean Astronomy and Astrology Cultures. Since mid-18th century after the enforcement of shixian-li (時憲曆), the Soganui and Ilseongjeongsiui handed over the Jeokdogyeongwiui (赤道經緯儀, equatorial armilla) by a change of the observational framework such as the time and angle measures. The Jeokdogyeongwiui made by Gwansanggam (觀象監, Bureau of Astronomy in Joseon Dynasty) adopted the new observational framework. We studied the structural characteristics and scientific values of these 3 astronomical instruments with theirs observation methods.

• Korean Journal of Acupuncture
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• 제31권4호
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• pp.158-167
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• 2014

Objectives : The results from randomized controlled trials on traditional medicine have been negative or ambiguous. The appropriateness of the research methodology started to be questioned. However, the research methodology appropriate for studying traditional medicine has not been well-established. This study aims to explore the appropriate research methodologies for clinical studies on acupuncture. Methods : Clinical researches evaluating the efficacy and effectiveness of acupuncture for back pain were systematically searched and evaluated focusing on research methodology. The acupuncture treatment protocol is evaluated by 9 items which is individual treatment based on diagnosis, combining proximal and distal acupoints, exact location of acupoint, De Qi, adequate stimulation, duration of acupuncture, treatment sessions, treatment interval, and establishing relationship between patients and doctors. Results : Systematic review of acupuncture researches on low back pain suggested that observational studies and pragmatic trials rather than explanatory studies could incorporate these elements. Qualitative studies also could help understanding complex characteristics of acupuncture treatment which could not be evaluated by quantitative studies. Conclusions : In designing clinical researches on acupuncture, various study designs, especially observational study and pragmatic study, should be considered according to research objectives and subjects. The efforts to incorporate the core characteristics of acupuncture practiced in everyday clinical setting are also essential.

• 한국게임학회 논문지
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• 제15권3호
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• pp.87-96
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• 2015

재미와 행복은 인간이 추구하는 본질적 가치이다. 게임은 그러한 본질적 가치를 만족시키는 매우 편리한 수단 중 하나이다. 그 수단을 교육에 접목하여, 재미있는 교육을 추구하는 시도들이 활성화되고 있다. 기업과 학교의 인력교육 현장에서 게임의 활용도가 증가하면서, 게임을 접목한 교육방식의 한계와 역효과에 대한 우려의 목소리도 생기고 있다. 역효과와 한계점을 명확히 이해하고, 이에 대한 극복방안을 모색하여 교육 게이미피케이션을 활성화하는 것이 본 논문의 목적이다. 본 논문에서는 인력교육 현장에서 게이미피케이션을 통해 교육에 게임을 접목할 경우에 발생하는 역효과와 한계점을 관찰연구를 통해 정리하고, 이에 대한 피교육자의 의견을 인터뷰 형식으로 추가하였다.

• 국제물리치료학회지
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• 제11권1호
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• pp.1954-1959
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• 2020

Background: Due to aging, blood flow rate decreases, also posture and chewing habit may be changed. Objective: To identify that changes in blood velocity in the common carotid arteries (CCAs) in old persons with unilateral chewing habit (UCH) and forward head posture (FHP) in the elderly. Design: An observational cross-sectional study. Methods: Chewing habits, FHP, and CCAs velocities were assessed in 85 elderly subjects. Chewing habits were measured by visual observation. CCAs measured the peak systolic velocity (PSV), end-diastolic velocity (EDV), minimum diastolic velocity, and resistivity index. The subjects were divided into UCH and bilateral chewing habit groups depending on chewing habit. The subjects were also divided into >49 degrees and <49 degrees for comparison of blood flow between the left and right CCAs. Results: In the UCH, the chewing side had significantly higher EDV (P=.003), PSV (P=.023) than the non-chewing side. There was no significant difference in velocity between the CCAs in the FHP. Conclusion: This study shows that the blood flow velocity of the chewing side of UCH was higher, and unilateral chewing affects the CCAs velocity and thus highlight the importance of chewing habit in the elderly than head posture.