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        검색결과 7

        1.
        2024.03 구독 인증기관·개인회원 무료
        In South Korea, the level of Highway Pavement Management System (HPMS) was developed since early 2000. During this time numbers of professional pavement condition monitoring equipment were developed and applied in the actual field. One of the remarkable results is 3D Pavement condition Monitoring profiler vehicle (3DPM) designed and developed in Korea Expressway Corporation Research Division (KECRD). Thanks to this equipment, The surface condition of current pavement can successfully be monitored and proper following management strategy cab be established. However, the inner condition of pavement layer cannot be monitored dur to limitation of 3DPM equipment. In this paper, Bending Beam Rheometer (BBR) mixture creep test was performed to verify the effectiveness of current 3DPM equipment. It was found that the current 3DPM equipment has reasonable feasibility on surveying pavement condition.
        2.
        2024.03 구독 인증기관·개인회원 무료
        Evaluation of low temperature performance of asphalt mixture is significant not only for mitigating transverse thermal cracking but also for preventing potential traffic accidents. In addition, the engineers in pavement agency need to inform the proper pavement section where urgent management is needed. Since early 2000, Korea Expressway Corporation Research Division (KECRD) developed an 3D Pavement condition Monitoring profiler vehicle (3DPM) to survey expressway pavement surface condition precisely. The management of whole expressway network became more precise, effective and efficient than before due to application of 3DPM and HPMS. One thing recommended is: performing extensive mechanical test and corresponding data analysis work procedure to further strengthen the feasibility of current 3DPM approach and HPMS. In this paper two activities were considered: first, the pavement section where the urgent care is recommended is selected by means of 3DPM approach. Then asphalt mixture cores were acquired on that specified section then low temperature fracture test: Semi Circular Bending (SCB) test, was performed. The mechanical parameters, energy release rate and fracture toughness were computed then compared. It is concluded that the current 3DPM approach in KEC can successfully evaluate and analyze selected pavement condition. However, more extensive experimental works are needed to further strengthen the current pavement analyzing approaches.
        3.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The evaluation of the low-temperature performance of an asphalt mixture is crucial for mitigating transverse thermal cracking and preventing traffic accidents on expressways. Engineers in pavement agencies must identify and verify the pavement sections that require urgent management. In early 2000, the research division of the Korea Expressway Corporation developed a three-dimensional (3D) pavement condition monitoring profiler vehicle (3DPM) and an advanced infographic (AIG) highway pavement management system computer program. Owing to these efforts, the management of the entire expressway network has become more precise, effective, and efficient. However, current 3DPM and AIG technologies focus only on the pavement surface and not on the entire pavement layer. Over the years, along with monitoring, further strengthening and verification of the feasibility of current 3DPM and AIG technologies by performing extensive mechanical tests and data analyses have been recommended. METHODS : First, the pavement section that required urgent care was selected using the 3DPM and AIG approaches. Second, asphalt mixture cores were acquired from the specified section, and a low-temperature fracture test, semi- circular bending (SCB) test, was performed. The mechanical parameters, energy-release rate, and fracture toughness were computed and compared. RESULTS : As expected, the asphalt mixture cores acquired from the specified pavement section ( poor condition – bad section) exhibited negative fracture performances compared to the control section (good section). CONCLUSIONS : The current 3DPM and AIG approaches in KEC can successfully evaluate and analyze selected pavement conditions. However, more extensive experimental studies and mathematical analyses are required to further strengthen and upgrade current pavement analysis approaches.
        4,000원
        4.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적 : 입체경으로 구현된 가상공간에서 측정한 사위검사를 하웰 시표를 기반으로 하는 기존 검사와 비교하여 효용성을 알아보고자 하였다. 방법 : 전체 대상자는 51명(20~39세)으로 전신질환, 안질환, 억제가 없고, 입체시가 40 sec 이상, 나안 또는 교정시력이 양안 1.0 이상인 사람을 선정하였다. 입체경의 광학렌즈 굴절력은 +3.00 D, +5.00 D, +10.00 D이 고, 광학중심점 간 거리는 62.00 mm이었다. 하웰 시표를 기반으로, 기존과 입체경용 사위도 검사 시표를 제작하 였으며, 검사거리 500.00 cm, 40.00 cm, 33.00 cm에 대해 수평과 수직사위도 검사를 무작위로 수행하였으며, 계산 조절성폭주비를 구하였다. 결과 : 검사거리 500.00 cm, 40.00 cm 및 33.00 cm에서 측정한 기존, +3.00 D, +5.00 D, +10.00 D 입체경 에서 수평사위(△)는 각각 -1.18±1.71, +2.39±3.46, +2.23±3.36, +2.36±3.31(500.00 cm), -3.88±4.17, -4.92±5.92, -4.98±5.70, -4.91±5.58(40.00 cm), 및 -5.53±4.82, -6.50±6.67, -6.49±6.59, -6.38±6.54 (33.00 cm), 수직사위(△)는 각각 -0.03±0.97, -0.03±0.99, -0.03±0.87, +0.02±1.00(500.00 cm), 0.00±0.92, -0.05±1.00, -0.09±1.01, -0.02±1.02(40.00 cm), 및 -0.05±0.99, -0.01±1.00, -0.11±1.02, -0.05±0.99(33.00 cm)로 나타났다. 입체경의 원거리 수평사위에서 더 내사위, 근거리는 더 외사위 방향으로 나 타났으며, 원거리만 통계적으로 유의한 차이가 있었고(p<0.050), 수직사위는 유의한 차이가 없었다(p>0.050). 계 산 조절성폭주비(△/D)는 각각 5.18±1.24, 3.34±1.45, 3.38±1.37, 3.36±1.35(40.00 cm), 및 4.81±1.22, 3.30±1.41, 3.36±1.41, 3.35±1.38(33.00 cm)이었으며. 입체경에서 더 낮았으며, 유의한 차이가 있었다 (p<0.050). 결론 : 입체경을 이용한 사위도 검사는 구현된 가상공간에 대한 거리감 인지가 실제공간과 다르기 때문에 원거 리 과폭주, 근거리 저폭주의 영향이 발생되었다. 실제공간과 유사한 수준을 가지기 위해서는, 거리감 인지를 증가 를 위한 주변부 가상공간에 경험적 단서를 추가시킬 필요가 있다고 판단된다.
        4,000원
        5.
        2016.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        현재 항로표지시설에 대한 객관적 지표 및 평가기준에 따른 적정성 및 효용성 등 사후평가는 설치 이후 항만 운영 중 변경될 수 있는 위험요소 및 환경 변화를 고려하여 이루어지지 않고 있는 실정이다. 항로표지시설에 대한 객관적 지표를 설계하여 모든 항로표지시설에 공통된 평가기준 및 분석모델을 적용하여 환경 및 항만 여건 변화에 따른 적정성 및 효용성을 분석할 필요성을 인식하고, 이 연구에서는 우선적으로 항로표지시설 중 전국 37기가 운영 중인 유인등대를 중심으로 20개의 기능평가 지표를 설계하고 적용하였다. 객관적 평가지표에 따라 기능평가 후 계층분석과정(AHP, Analytic Hierarchy Process) 기법을 통해 항만 운영의 특성, 국가정책, 전문가 의견 등을 반영하였으며, 항로표지시설의 특수성 평가를 위해 리커트척도(Likert scale)를 적용하여 사후평가 하였다. 효용성분석 결과 전체 37기 중 영도등대, 가거도등대, 거문도등대, 죽변등대의 기능 및 효용성이 높은 것으로 분석되었으며, 울릉도등대, 가사도등대, 송대말등대, 울기등대의 경우 세부적인 적정성분석이 이루어질 필요가 있는 것으로 분석되었다. 이러한 항로표지시설 효용성분석은 항로표지시설의 관리체계의 효율성 향상, 항로표지의 재배치 및 정책결정을 위한 기초자료 등으로 활용할 수 있을 것이다.
        4,000원
        6.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Real-life time series characteristic data has significant amount of non-stationary components, especially periodic components in nature. Extracting such components has required many ad-hoc techniques with external parameters set by users in case-by-case m
        4,000원
        7.
        2010.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The purpose of the study was to explore the reflective process of pre-service English teachers by analyzing critical incidents entered in their teaching journals during a fourweek student teaching practicum. Thirty-three student teachers were asked to report critical incidents in their journals once a week, especially focusing on „lesson breakdowns‟ or „events that deserve critical significance‟ during a lesson. 133 journal entries were collected and a total of 104 critical incidents were analyzed to see some aspect of secondary classroom teaching and the reflective processes that student teachers went through right after the incidents. From the content analysis, it was found that many critical incidents happened during the initial stage of lesson and were mostly caused by student teachers‟ lack of experiences in either time management or material preparation tailored to students‟ level. By describing and analyzing critical incidents, student teachers became more aware of their assumptions about language teaching and learning and tried to transfer knowledge into real practices. A survey administered after the practicum also revealed that self-observation of critical incidents in their own classroom helped them to generate powerful insights about teaching and to develop reflective teachers.
        7,000원