• Title/Summary/Keyword: 결함 규명

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A Correlation Analysis of Influence Factors of Nonconformity in Construction Projects (건설프로젝트의 품질결함의 발생요인간 상관분석)

  • Chi, Sungjoon;Cha, Yongwoon;Han, Sangwon
    • Korean Journal of Construction Engineering and Management
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    • v.16 no.2
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    • pp.21-28
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    • 2015
  • Construction defects are major components that result in cost overruns and schedule delays in construction projects. There have been extensive research efforts to investigate the cause of defects. However, little effort has been devoted to analyze correlation among various reasons of construction defects while a defect is not usually an outcome of a single cause, but rather occurs when several interrelated causes combine. Based on this recognition, this paper analyzes 831 nonconformity reports collected from 30 construction projects in Korea from 2011 to 2014. The correlation analysis revealed that a significant portion of construction defects occurred in the procurement and construction phase and as the pattern of function defect and installation defect. Triggered by human error, defective material and faulty method, these defects are treated by conccession, repair, rework that can significantly lower the cost and schedule performance. This paper is significant in terms of providing a theoretical basis for analyzing correlation among various reasons of construction defects and quantitative measures for establishing effective defect prevention strategies.

Identification of Defect Frequencies in Rolling Element Bearing Using Directional Spectra of Vibration Signals (구름 베어링의 결함 주파수 규명을 위한 방향 스펙트럼의 이용)

  • 박종포;이종원
    • Journal of KSNVE
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    • v.9 no.2
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    • pp.393-400
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    • 1999
  • Defect frequencies of rolling element bearings are experimentally investigated utilizing the two-sided directional spectra of the complex-valued vibration signals measured from the outer ring of defective bearings. The directional spectra make it possible to discern backward and forward defect frequencies. The experimental results show that the directional zoom spectrum is superior to the conventional spectrum in identification of bearing defect frequencies, in particular the inner race defect frequencies.

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Efficiency Analysis of Cardiac Hand Acupuncture by Measuring the Bio-Image Signals (생체 영상신호 측정을 통한 심장 수지침 효능 분석)

  • Kim, Bong-Hyun;Cho, Dong-Uk
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.7
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    • pp.3319-3325
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    • 2013
  • In this paper, hand acupuncture used as a way of life medicine in everyday life, the influence of human organ will be investigated by applying IT techniques. For this, hand acupuncture is based on priority of the most important organ in the human body to target the cardiac associated with cardiac reflex point A16 acupuncture point before and after for 5 min to stimulation of facial images were collected and applied to the Lab color system associated with the cardiac, color value of cheonjung and lips region were measured for comparison and analysis. Finally, by measuring the change in bio-image signals A16 acupuncture point stimulation effects on cardiac function were performed to investigate the effectiveness of acupuncture. Also, statistical significance tests from the experimental results were performed whether the experimental results is valid or not.

The Relationship among Loneliness, Stress, and Smartphone Addiction of Adolescents in the Era of Digitalization (디지털 시대 청소년의 외로움, 스트레스, 스마트폰 중독의 영향관계)

  • Kim, Ji-Youngng
    • Journal of Digital Convergence
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    • v.15 no.9
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    • pp.335-343
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    • 2017
  • Several studies have suggested that lonely adolescents showed higher increases in stress and they easily addicted smartphone utilization for comforting loneliness and stress. Studies, moreover, have claimed that smartphone addiction has negative effects on mental health of adolescents. To contribute to knowledge on these topics, this study is to investigate to the relationship among adolescents' loneliness, stress, and smartphone addiction. To identify test subjects, the study conducted a survey that collected data from Korean adolescents, and the survey of this study was completed between April 1, 2017 and April 15, 2017. A total of 356 adolescents completed the survey, and the final data of empirical test of the study was 327. The empirical results demonstrate that the relationship between loneliness and stress of adolescents is mediated by four sub-factors of smartphone addiction such as difficulty of daily life, directivity of virtual life, withdrawal symptom, and tolerance. The results indicated that a smartphone addiction risk of adolescents was negatively related to their mental health, especially loneliness and stress.

사회화 경험과 여성 기업가 활동의도의 관계에 대한 개인 및 맥락 효과: 성별 및 사회안전성의 삼원조절효과

  • Gong, Hye-Won
    • 한국벤처창업학회:학술대회논문집
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    • 2018.11a
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    • pp.239-251
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    • 2018
  • 최근 들어 기업가적 활동을 촉진하는 데 있어 무엇보다도 여성의 경제활동 참여와 사회안전망 구축의 필요성이 제기되고 있는바, 본 연구에서는 사회화경험과 기업가 활동의도의 관계에 대한 맥락적 차이 규명에 초점을 두고, 이들 관계에 대한 성별의 조절 효과와 사회안전망의 삼원조절효과에 대해 규명하고자 한다. 본 연구 목적은 다음과 같다. 첫째, 사회화경험(창업경험, 기업가정신 교육경험)이 기업가 활동의도에 미치는 효과를 규명하고, 이들 관계에 대한 성별의 조절효과를 검증한다. 둘째, 사회화경험 및 기업가정신 교육과 기업가 활동의도의 관계에 대한 성별 조절효과가 사회안전망과 같은 국가 맥락적 차이가 존재하는지에 대해 삼원상호작용 분석을 통해 검증한다. 상기 연구목적을 달성하기 위해 본 연구는 (재)한국청년기업가정신재단에서 제공한 글로벌 기업가정신 추세 리포트(GETR) 자료를 활용하였다. GETR자료는 한국을 포함한 총 20개국(한국, 일본, 중국, 인도네시아, 인도, 싱가포르, 런던, 독일, 러시아, 덴마크, 핀란드, 영국, UAE, 이스라엘, 남아공, 터키, 이집트, 미국, 브라질, 칠레, 호주)을 대상으로 국가별 최소 2,000명을 표본으로 선정해 설문조사가 이루어진 자료이며, 유효 응답자 기준 총 40,388명이 설문에 응답하였다. 그러나 자료 검증과정에서 전체 응답자 중 2,506명이 불성실 응답자 및 이상치로 확인되어 최종 분석과정에서 삭제되었다. 따라서 37,882개의 표본이 최종 분석에 활용되었으며, 여성 17,997명 (47.5%), 남성 19,885명(52.5%)으로 확인되었다. 분석 도구는 Hayes의 Process를 활용하여 사회화 및 교육, 성별, 성별 격차의 삼원상호작용 효과에 대한 분석이 이루어졌다. 분석 결과, 첫째, 창업경험 및 기업가정신 교육경험은 기업가 활동의도에 유의한 영향을 미치는 것으로 나타났다. 둘째, 이들 관계에 대한 성별 조절효과를 살펴본 결과, 성별 조절효과는 기업가정신 교육경험과 기업가 활동의도의 관계에 대해서만 유의한 영향을 미치는 것으로 확인되었다. 구체적으로, 기업가정신 교육경험이 기업가 활동의도에 미치는 긍정적 효과는 여성이 남성보다 더 강한 것으로 나타났다. 마지막으로, 사회안전망의 삼원조절효과를 분석한 결과, 창업경험과 기업가 활동의도의 긍정적 관계는 여성이 남성보다 더 강한 것으로 나타났는데, 이러한 효과는 사회안전망이 높은 집단에서 더 높게 나타나는 것으로 확인되었다. 즉, 과거 창업경험이 있는 여성은 사회안전망이 높다고 인식할 경우 과거 창업경험이 있는 남성보다 기업가 활동의도가 더 많이 증가하는 것이다. 이와 관련된 논의는 본문에 제시하였다.

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Analysis of Application Cases and Evaluation of Effectiveness on Portable Dynamic Cone Penetration Test (DCPT) to Identify the Deterioration Cause of Damaged Reinforced Earth Walls (보강토옹벽의 피해원인 규명을 위한 휴대형 동적콘관입시험(DCPT) 적용사례 분석 및 효용성 평가)

  • Lee, Kwang-Wu;Cho, Sam-Deok
    • Journal of the Korean Geosynthetics Society
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    • v.19 no.4
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    • pp.95-109
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    • 2020
  • In this study, a total of six site cases were reviewed to assess the site applicability of portable dynamic cone penetration test (DCPT) by identifying the cause of damage to the damaged reinforced earth wall using portable dynamic cone penetration test. An improved dynamic concrete penetration tester was used at the site to enable ground surveys of more than 6 meters. The test results were compared with the results of the standard penetration test (SPT) and the correlation was analyzed. Through the analysis of various field application cases, it was found that portable dynamic cone penetration test was very convenient to apply at the site of the damaged reinforced earth wall, and DCPT could play a major role in identifying the cause of damage and verifying stability of the retaining wall by continuously identifying the ground strength. In addition, it was found that the results of the dynamic cone penetration test and the standard penetration test showed a correlation of N≒(1/3~2/3)·Nd in sandy soil.

A Research on the Successful Introduction Strategy for SW Education in K-12 focusing on the Perceptions of K-12 Students and Teachers on SW Education (초·중등학교에서 성공적인 SW교육 정착을 위한 방안 모색 - 초중등 학생 및 교사의 SW교육에 대한 인식을 중점으로 -)

  • Suh, Soonshik
    • Journal of Creative Information Culture
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    • v.5 no.2
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    • pp.135-143
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    • 2019
  • In this study, the perceptions on SW education of K-12 students and teachers were surveyed and analyzed. At the primary school level, there was no significant difference in SW attitude based on school location. However, at the secondary level, students from metropolitan areas showed significantly higher SW attitude scores. In the case of gender, male students showed higher SW attitude scores both in primary and secondary schools. With regard to attitude differences based on prior experience of SW education, students with prior experience showed higher attitude scores in SW education in both primary and secondary schools. The awareness survey among teachers showed that both primary and secondary school teachers showed positive responses to SW education. For the successful induction of the SW education at K-12, four factors (participants, curriculum, teaching-learning method, and support from inside and outside of school) were highlighted.

Analysis of Intersection Signal Violation Accident Using Simulation (시뮬레이션을 이용한 교차로 신호위반 사고 해석)

  • Han, Chang-Pyoung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.1
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    • pp.424-430
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    • 2021
  • Determining the cause of a traffic signal violation is difficult if the drivers' claims are contradictory. In this study, the process of identifying signal violations using a simulation was presented based on cases. First, statements from the driver or witness whose cause of the signal violation is unclear were excluded. Second, the final position, final location, damaged area, steering status, braking status, and road surface traces of the vehicle were collected. The impact point was investigated from the stop line. Third, simulation data were modified and entered until the collision situation of the accident vehicle and the final stop position were met. Fourth, if the simulation results were consistent with the crash situation, the facts were verified by cross-validation to conform to the driver's statement. The results of the simulation showed that the Lexus entered the left turn signal in the intersection at approximately 55 km/h. In comparison, the Sonata driver saw the vehicle straight ahead at the intersection, entered the 72 km/h intersection, and collided with the Lexus. Therefore, the Sonata was identified as a signal violation, and the claims of the Sonata driver, witnesses, and police were contradictory.

Identification of Anti-oxidant, Anti-aging, and Whitening Effects of Diospyros kaki Extracts (감 추출물의 항산화, 항노화 및 미백 기능 규명)

  • Hong, Chang-Eui;Lyu, Su-Yun
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.48 no.3
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    • pp.275-285
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    • 2022
  • In this study, we prepared two extracts using 1,3-butylene glycol (DBG) and ethanol (DET), with Diospyros kaki and determined the anti-oxidant, anti-aging, and whitening effects in vitro. Anti-oxidant activity was measured by DPPH and superoxide dismutase (SOD) method, and as a result, both DBG and DET extracts confirmed their anti-oxidant properties by exhibiting significant DPPH scavenging and SOD-like activities. For anti-aging activity, we measured elastase and hyaluronidase inhibition, and the inhibition of MMP-1 expression. Both DBG and DET significantly inhibited elastase and hyaluronidase activities dose-dependently, and MMP-1 expression was also reduced in both extracts. We also measured the whitening effects with tyrosinase activity and melanin production, but only DBG showed a decrease in tyrosinase. In summary, D. kaki extract has strong antioxidant, anti-aging, and whitening functions, and it is believed that it can be used as a cosmetic material in the future.

Development of a Path-Based Trip Assignment Model under Toll Imposition (통행료체계에서의 경로기반 통행배정모형 개발)

  • 권용석;박창호
    • Journal of Korean Society of Transportation
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    • v.18 no.6
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    • pp.77-88
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    • 2000
  • 이용자의 경로선택 형태를 모사하는 통행배정모형 결과의 정확도는 교통계획에 상당한 영향을 미친다. 이용자의 경로선택 결정과정에서 가장 중요한 판단기준은 통행시간과 통행요금이다. 그런데 통행요금은 이용자의 경로 거리에 따라 다양한 방식으로 부과되므로, 링크를 분석단위로 하는 기존의 통행배정모형은 현실적인 통행요금 반영이 힘들었고 또한 수요예측 결과를 이용한 다양한 분석에서 제약을 받아 왔다. 본 연구는 이러한 배경에서 경로교통량을 도출할 수 있는 경로기반 통행배정모형을 구축하였고, 또한 경로거리에 따라 결정되는 현실적인 통행요금을 반영할 수 있는 알고리즘을 개발하였다. 경로기반 배정모형에서는 GP(Gradient Projection) 알고리즘을 이용하였고, 계산상의 효율성 제고를 위해 K-최단경로 알고리즘 중 MPS(Minimal Path Search) 알고리즘을 이용하였다. 개발된 배정모형은 현실적인 통행요금을 반영할 수 있으므로 통행배정 결과의 정밀도를 향상시켰을 뿐만 아니라 기존 배정모형에 비해 최적해로의 수렴속도도 개선되는 것으로 나타났다. 본 논문의 배정모형은 경로교통량이 도출되고 통행요금을 반영할 수 있으므로, 통행요금과 통행거리 관계에 따른 목적함수의 규명과 그에 따른 효과척도를 계량화할 수 있다. 따라서 본 모형은 통행배정에서 실재상황을 보다 현실여건에 맞도록 규명할 수 있고, 기존의 제한적인 효과분석의 문제점을 해결할 수 있으므로 그 활용범위가 넓다.

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