• Korean Journal of Ecology and Environment
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• v.50 no.2
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• pp.195-206
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• 2017

We described a spatial distribution pattern and floral diversity on the Paspalum distichum community occurring at the ecological parks of Hwamyeong, Daejeo, Samnak, and Maekdo in the Nakdong river estuary. A total distribution area of P. distichum community was $303,462.6m^2$. Its largest area was found in Samnak eco-park ($185,910.1m^2$). The most richness of knotgrass patches in each ecological park was determined Maekdo eco-park (87). Cover class level-5 shows the largest area ($260,663.2m^2$). A total of 73 taxa (34 families, 55 genus, 65 species, and 8 varieties) were listed up on the P. distichum community. A welldeveloped population of knotgrass was found predominantly at sites linked into human impacts at the riverine floodplain, the stream courses flowing through the parks, and the man-made channels and wetlands. Finally we proposed an ecological management strategy for knotgrass population in the study area.

• Journal of the Korea institute for structural maintenance and inspection
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• v.2 no.1
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• pp.81-88
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• 1998

과적차량의 통행에 의한 교량구조물의 손상도를 평가하는 방법의 개발이 매우 활발하다. 본 연구에서는 과거 15년동안 통행한 교통데이타를 분석하고, 이 데이타를 근거로 교량의 손상도를 분석한다. 차량의 분류는 4종으로 대표하여 차량하중을 분석하였으며 해석시에는 이를 대표하는 2종을 사용하였다. 3차원해석을 통하여 구한 영향면을 이용하여 부재력을 계산하고 이를 이용하여 등가응력범위를 구한다. 이 결과는 모형실험을 통하여 구한 피로결과와 비교하였다. 분석결과 설계하중을 초과하는 과적차량이 교량에 미치는 손상정도는 적은 통행빈도에도 불구하고 매우 큼을 알 수 있고, 이러한 실제교통량의 분석을 통한 교량의 손상평가방법은 과적차량에 의한 교량손상정도를 유용하게 평가할 수 있다.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1897-1898
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• 2008

본 논문에서는 비젼을 이용한 영상처리 기술을 기반으로 운전자의 피로도를 측정하여 졸음운전을 감지하여 경고하는 실시간 시스템을 제안한다. 제안된 시스템은 얼굴 영상 분석과 퍼지 이론을 이용하여 운전자의 졸음 또는 부주의함을 감지하여 경고함으로서 교통사고를 미연에 방지하는 시스템이다. 본 논문에서는 실시간 얼굴 탐색 알고리즘 개발을 위해 퍼지 색상 필터와 가상 얼굴 모형을 이용하여 얼굴위치 및 눈 영역을 보다 빠르게 검출하고, 눈 깜박임의 빈도수(Eye blinking frequency)와 눈의 닫힘 지속 기간(Eye closure duration)을 측정하는 방법은 제안한다. 그 다음, 측정된 데이터를 기반으로 퍼지논리를 사용하여 운전자의 피로도를 결정하고 졸음운전 여부를 감지 및 판단하는 방법을 제안한다. 마지막으로, 제안된 방법은 여러 실험을 통해 운전자의 졸음운전 감지 능력의 우수성을 증명한다.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.2
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• pp.223-229
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• 2008

In this paper. we propose the real-time vision system which judges drowsiness driving based on levels of drivers' fatigue. The proposed system is to prevent traffic accidents by warning the drowsiness and carelessness using face-image analysis and fuzzy logic algorithm. We find the face position and eye areas by using fuzzy skin filter and virtual face model in order to develop the real-time face detection algorithm, and we measure the eye blinking frequency and eye closure duration by using their informations. And then we propose the method for estimating the levels of drivel's fatigue based on measured data by using the fuzzy logic and for deciding whether drowsiness driving is or not. Finally, we show the effectiveness and feasibility of the proposed method through some experiments.

• Journal of Convergence for Information Technology
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• v.8 no.6
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• pp.101-106
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• 2018

We examined refractive error, the corrected visual acuity, phoria and fusional reserve of 114 healthy myopes and hyperopia who had no strabismus, no ocular and physical diseases. We evaluated the occurrence of asthenopia according to phoria and fusional reserve. 41 out of 114 subjects which exophoria was 69% and esophoria was 5.5%, orthophoria was 26% made a complaint against asthenopia. The subjects who had exophoria of $0-6{\Delta}$ in the range of normal state was 61.4%, while the subjects who had exophoria of $7{\Delta}$ or more in the range of abnormal state was 38.6%. Reducing fusional reserve was associated with increasing phoria. The fusional reserve twice or more than phoria were 27.2%, and twice or under were 72.8%. Futhermore, AC/A ratio for heterophoria was found from 1.0 to 12.6 and its relationship to asthenopia of phoria could not be determined.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.419-424
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• 2006

본 연구는 데스크탑 PC 환경에서 사용될 수 있는 다양한 적응형 메뉴 인터페이스의 사용성을 평가한다. 선택 빈도에 따라 자동으로 변화하는 2가지 방식의 Adaptive menu와 사용자가 메뉴 내에서 원하는 항목의 위치를 직접 변경하는 Adaptable menu의 사용성을 일반적으로 많이 이용되는 Traditional menu와 비교하기 위해 사용자를 동원한 평가 실험을 수행하였다. Adaptive menu에는 선택 빈도가 높은 메뉴 항목이 메뉴의 상단으로 이동하는 Adaptive split menu와 자주 선택되는 항목이 굵은 글씨로 표현되는 Adaptive style menu가 포함된다. 각 방식의 적응형 메뉴가 자주 선택되는 메뉴 항목의 변화에 따라 얼마나 민감하게 영향을 받는지 비교하기 위해, 두 개의 각기 다른 선택 빈도 분포가 이용되었다. 각 실험 조건 별로 사용자가 메뉴 항목을 선택하는 데 걸린 시간과 오류 회수를 측정하였으며, 피실험자로 하여금 시인성, 효율성, 전반적 선호도 등의 주관적인 만족도를 평가하도록 하였다. 각각의 종속 변수들은 분산 분석(ANOVA), Chi-square test, Friedman test 등의 기법을 이용해 분석되었다. 분석 결과, Adaptable menu가 다른 방식의 메뉴들에 비해 수행도와 만족도 모두 높은 것으로 나타났으며, Adaptive split menu는 상대적으로 현실적인 조건 하에서 큰 효용을 갖지 못하는 것으로 나타났다. Adaptive style menu는 수행도 측면에서는 일반적인 메뉴와 큰 차이가 없었지만, 자주 선택되는 항목을 쉽게 파악할 수 있게 해 주고, 선택 빈도의 변화에도 민감하지 않기 때문에 사용자들에게 선호되는 것으로 나타났다. 본 연구의 결과는 데스크탑 PC의 적응형 메뉴 설계에 대한 이용될 수 있으며, 추후 휴대용 정보기기의 적응형 메뉴에 대한 사용성 연구의 기초 자료로도 활용될 수 있을 것으로 기대된다.

• Journal of Korean Society of Steel Construction
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• v.9 no.3 s.32
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• pp.363-375
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• 1997

This study encompasses the performance of static and fatigue test for the 8 large scale test specimens to clarify the fatigue behavior of coped stringer and the effect of the repair and strengthening on the damaged stringer of the floor system in steel railway bridges. For the purpose of the research, the actual stress wave for the existing bridge was measured, the basic stress range frequency histogram was made and the equivalent stress range was calculated. Using the result from the equivalent stress range made by adjusting the stress range, the static and fatigue test was carried out by identifying the previous rehabilitation and after. As the result of the static tests, it was revealed that the level of local stress under the S1 specimen test of the real equivalent stress range was similar to tensile strength of the test material, and it was consistent with the requirement of the initiation condition of the fatigue crack. Through the various rehabilitation methods to the damaged specimens, the effects of the repair and reinforcement were analyzed. According to the results of the repair of effect, bolting the high tension bolt over the stop hole was confirmed to be more adequate method than drilling only stop hole to delay the fatigue crack growth. Futhermore, in case of the stringer subjected by bending moment, the reinforcement over the upper flange side was determined to be a useful strengthening method, and the reinforcement to the web of the stringer was not appropriate to accomodate as a adequate strengthening method. Also it was confirmed that the category of the fatigue design for the coped stringer met with the category E specified on the fatigue design criteria of the Highway Standard Specification in Korea.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.4
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• pp.533-538
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• 2014

Purpose: This study is to investigate correlation between eye fatigue and letter contrast according to letter contrast changes on monitor display. Methods: Reading speed test were carried out for 53 subjects (mean age: $22.68{\pm}1.85$ years) who have over Best-corrected visual acuity (BCVA) 1.0, and 45 subjects, who could read over 123 out of 163 letters among 53 subjects were selected. They were asked to read the letters which were composed of Black (contrast 100%), Dark gray (contrast 80%), Gray (contrast 80%), Light gray (contrast 30%) randomly. The change of their eye fatigue by letter contrast on monitor display was measured by monitoring their eyes with an eye-tracker while they were reading letters. Results: Event Duration (sec) was 33.635 for Black, 32.266 Dark gray, 33.936 for Gray, and 34.848 for Light gray. Average of Fixation Duration (sec) was 0.224 for Black, 0.218 for Dark gray, 0.239 for Gray and 0.243 for Light gray. Average of Pupil diameter (mm) was 41.133 mm for Black, 41.160 mm for Dark gray, 40.880 mm for Gray and 40.459 mm for Light gray. Frequency (blinks/sec) was 0.211 for Black, 0.206 for Dark gray, 0.221 for Gray, and 0.238 for Light gray. Conclusions: Event Duration and average of Fixation Duration were the shortest for Dark gray and the longest for Light gray. In average Pupil diameter was the biggest Dark gray and the smallest for Light gray. Blink Frequency (blinks/sec) was the lowest for Dark gray and the highest for Light gray. Visual fatigue by brightness of letters on monitor display was the least for Dark gray followed by Black, Gray and Light gray.

• Journal of Korean Library and Information Science Society
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• v.49 no.4
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• pp.53-71
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• 2018

The purpose of this study was to identify bibliographic characteristics of the top level articles among KCI indexed academic articles. Unlike the existing analysis on citation and most-cited articles, this study analyzed their bibliographic characteristics. The 3,453 articles were collected from 17 social science fields in KCI. The characteristics of authors, institutions, publications, journals, and citations were analyzed. According to the result of the analysis, there was a difference in the ratio of single authors to co-authors and in the number of co-authors. The authors were mostly single authors or two co-authors. In general, the percentage of authors of one article was high. Second, the types of institutions were mostly universities, and there were differences in the number of institutions with authors in each field. And the frequency of the authors' affiliation appeared uneven. There were a number of excellent research institutes and authors depending on the field. Third, the average of years to take to become the top articles for publication was 11 years in 2018. Fourth, most of the published journals were KCI registered journals, and the influence of the journals was not a factor. Fifth, there were differences in the number of cited counts between fields. This study is meaningful to grasp the influencing factors on the bibliographic characteristics of the most-cited articles for the social science field.

• Journal of the HCI Society of Korea
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• v.13 no.3
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• pp.35-42
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• 2018

Social Networking Sites (hereafter SNSs) have become a part of people's daily routines. Beginning as a hobby/communicating tool for a specific group of people, SNSs have expanded in terms of the number of users, frequency of access, and depth and range of sharing. It is recently reported that the users experience SNS fatigue from being connected at all time. However, limited research has addressed this issue. The purpose of the present study was to examine the mediating role of reputational concern and expectation of others' responses on the relationship between narcissism and Facebook fatigue. A total of 329 Facebook users completed an online survey. The results showed that individuals who rated high on narcissism experienced a high level of Facebook fatigue, and that both reputational concern and expectation of others' responses partially mediated the relationship between narcissism and fatigue. Implications of the findings and suggestions for future research are discussed.