• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2003년도 봄 학술발표회 논문집
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• pp.701-708
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• 2003

Recently, piezocone penetration test is frequently conformed in order to estimate the characteristics of soft ground with standard penetration test, generally used in the past. The soil characteristics, such as cone penetration resistance, friction resistence and excessive pore water pressure, can be evaluated continuously through the piezocone penetration test. In Incheon International Airport 2nd phase site preparation, standard penetration test and piezocone penetration test were used in order to increase the confidence for determination of soft ground depth. And the compressible layer was determined by the comparison between the preconsolidation pressure and the designed increase pressure. As the results, the relation between standard penetration test and piezocone penetration test shows q$_{c}$=(1.09~l.63)N at the soft ground, determined by 5/30 N value. And q$_{c}$=(1.21~l.98)N was shown at the point of compressible layer, evaluated by the preconsolidation pressure. These results were applied to determination for the depth of soft ground and to design the improvement for the soft clay.lay.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.3180-3186
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• 2011

A segmented scissors type switch has been developed for the urban transit maglev demonstration line to be commercialized near Incheon International Airport in 2013. Based on the design of the previous segmented 3-way switch, the scissors switch is composed of four segmented 2-way switches up/down and left/right and a turn table in the mid point. The main function of the scissors switch is to change the running direction of the train at end terminals. The developed scissors switch is planned to be installed in front of the 102 station, which has a side platform, of the demonstration line. The total length of the switch is 65m and the distance between the up and down track centerlines is 6m. The 2-way switches and turn table are made of steel box type beams, and have their own driving unit, locking unit, control unit, levitation and propulsion rails, and so on. Installed in the factory, a 100,000-cycle continuous operation test was carried out after manual and automatic test operations. The applicapability of the developed switch was verified through the measurements of the linearity of the track after repetitive operations, the mechanical operation noise, the load of the main driving motor, the safety of the control panel, the natural frequency of the girder, the deformation of the girder, and so on.

• 한국항행학회논문지
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• 제1권1호
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• pp.59-69
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• 1997

본 논문에서는 R-트리를 이용하여 항법 지리 데이타베이스를 구축하고 비행 시뮬레이터를 위해 VOR, ILS, DME, NDB 등의 항공전자 장치를 위한 소프트웨어를 개발한다. 먼저, R-트리를 이용하여 항법지리 데이타베이스를 설계하고 각 공항의 항법시설에 대한 데이타베이스를 구축한다. 항공전자 장치 소프트웨어 구현을 위해 VOR에서는 항공기와 VOR국 간의 거리, 방위각, 편위각 등을 계산하는 알고리즘을, ILS에서는 LLZ로 부터의 편위각, GP로 부터의 글라이드 슬로프로, 마커의 범위 등을 계산하는 알고리즘을 개발한다. 항법 지리 데이타베이스 시스템은 데이타베이스를 구축하고 갱신할 수 있는 항법지리 데이타 관리기, 항법전자장치에 관련된 정보를 제공하는 실시간 탐색기, 항법지리 데이타베이스, 그리고 사용자 인터페이스로 구성된다.

• 대한가정학회지
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• 제43권4호
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• pp.31-47
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• 2005

This study is a preliminary investigation into improving the environmental quality of schools. The purpose was to clarify the present conditions and reasons of noise in elementary schools located near airports and roads by noise level measurements and questionnaire surveys of subjective responses. fold measurements on equivalent and instantaneous noise levels, indoor and outdoor, were carried out in 3 schools during the periods 11th~ 13th of February and 2nd~ 7th of July,2003. The respondents were 94 teachers working in the 3 schools. The results were as follows. 1) Indoor noise levels of the 3 schools were 36.g~73 dB(A) in winter, and 46.9~ 91 dB(A) in summer. These values were higher than the indoor noise standard of 50 dB(A), except for the average of equivalent noise levels in winter.2) Outdoor noise levels of the schools were 41.1 ~ 101 dB(A) in winter, and 52.4~ 102 dB(A) in summer. These values were generally inappropriate relative to the standard for environmental noise of 65 dB(A). 3) The respondents showed relatively non- positive responses during school hours for interruptions by environmental noise.4) The frequently checked types of environmental noise of the schools were 'airplane noise','surrounding facilities', and 'traffic noise'. The frequently checked types of damage by environmental noise were 'Interrupting school hours' and 'Interrupting business'.

• 한국도로학회논문집
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• 제2권3호
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• pp.155-165
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• 2000

증가되는 항공교통량에 대해서 효율적으로 공항포장을 관리하기 위해서는 포장상태를 정기적으로 모니터링 할 필요가 있다. 이를 위하여 국내에서는 모든 공항에 대해 5년 주기로 포장평가를 실시하고 있다. 그러나 현재까지 사용된 기존의 포장 평가방법은 설계차트에 의한 원시적인 방법으로서 실제상황을 잘 반영하지 못한다라는 것이 문제점으로 지적되어 왔다. 본 연구에서는 과거의 설계차트에 의한 포장 평가방법과 새로이 국내에 적용된 외국의 해석적인 포장 평가방법을 비교, 분석함으로써 각 방법별 차이점을 제시하였다. 또한 "P" 공항에 대한 실제 사례 연구를 통해 각 방법별 허용하중 결과를 산출하였고 장단점을 분석하였다. 연구 결과로 포장의 구조적 지지력 평가는 설계차트를 이용하는 것보다 해석적 접근방법이 더 논리적인 접근인 것으로 분석되었다.

• Structural Engineering and Mechanics
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• 제61권2호
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• pp.255-266
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• 2017

In this study, self-supporting roofing elements especially convenient for large-span structures such as stadium, airport terminal, mall, coliseum, etc. were examined with respect to critical buckling load. These elements were assumed as laminated composite plates and, variation of free-edge forms, cutout types and lamination configurations were used as design parameters. Based on the architectural feature and structural requirements, the effects of curvilinear free-edge form on critical buckling load were focused on in this research. Within this scope, 14 types of lamination configuration were specified according to various orientation angle, number and thickness of plies with a constant value of total plate thickness. Besides that, 6 different types of cutout and 3 different free-edge forms were determined. By combining all these parameters 294 different critical buckling load analyses were performed by using ANSYS Mechanical software based on finite element method. Effects of those parameters on critical buckling load were evaluated referring to the obtained results. According to the results presented here, it may be concluded that lamination conditions have more significant influence on the critical buckling load values than the other parameters. On the other hand, it is perceived that curvilinear free-edge forms explicitly undergo changings depending on lamination conditions. For future work, existence of delamination might be considered and progression of the defect could be investigated by using non-linear analysis.

• 유통과학연구
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• 제18권2호
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• pp.39-48
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• 2020

Purpose: This study examines components that dictate service quality of Online Travel Agencies. Research design, data and methodology: This study performed a survey that targeted people who have purchased travel products using Online Travel Agencies in the past year at Incheon International Airport. Out of 280 questionnaires, this study selected 249(88.9%) questionnaires for analysis. In analysis, this study used statistical package called 'SPSS 22'. Results: Based on the results, this study identified that company reputation and transactional stability influenced consumers' intent to share anecdotal and practical information. Conclusions: This study discovered several major findings. First, 'convenience' and 'price', two major factors in service quality, imposed positive effects on word-of-mouth intention of consumers. In particular, 'convenience' had the most significant impact. Next, this study verified the moderating effects of 'transaction safety' and 'reputation' on the effect relationships between 'convenience' and 'price', and consumer word-of-mouth intention. The results conclude that, in fact, some statistically significant differences among the effect degrees of the two independent variables on the dependent variable according to the safety level of transaction on Online Travel Agencies website do exist. In short, 'transaction safety' variable does have moderating effects on the above relationships.

• 한국철도학회논문집
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• 제12권1호
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• pp.115-121
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• 2009

자기부상열차는 전자기력으로 차량을 부상, 추진하는 시스템으로써 친환경적이고 주행성능이 우수해 장래의 대중교통수단으로 각광받고 있다. 국내에서도 1989년 이후 자기부상열차와 그 시설물에 대한 연구가 진행되고 있으며 2012년 인천에 도시형 자기부상열차가 실용화될 예정이다. 도시형자기부상열차가 실용화되기 위해서는 자기부상 전용 가이드웨이의 성능이 확보되어야한다. 또한 자기부상열차는 나라마다 차량형식이 달라 국내 실정에 맞는 적절한 설계기준이 필요하다. 본 연구에서는 도시형자기부상 실용화 사업에서 제안된 자기부상 가이드웨이를 대상으로 유한요소해석을 수행하여 도시형 자기부상 가이드웨이의 단면성능을 평가하고 충격계수를 산출하였다. 해석수행 결과 동적증폭효과는 크지 않은 것으로 나타났으며 이를 통해 향후 자기부상 전용 가이드웨이 충격계수 설계기준 정립에 필요한 자료가 될 것이라고 기대된다.

• 한국건설순환자원학회논문집
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• 제3권1호
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• pp.22-33
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• 2015

Chloride ions in RC (Reinforced Concrete) structures can cause very severe corrosion in reinforcement steel. It is generally informed that chloride penetration can be considerably accelerated by enlarged chloride diffusion due to cracks. These cracks play a role in main routes through which chloride ions penetrate into the concrete, and also lead to steel corrosion in RC structures exposed to chloride attack, such as port and ocean structures. In this paper, field survey including evaluation of crack and chloride concentration distribution in concrete is performed to investigate an effect of crack on chloride diffusion. The service life of cracked concrete exposed to the marine environmental condition is estimated considering the crack effect on chloride diffusion. For this purpose, diffusion coefficients in cracked concrete are obtained based on the field survey. Using the relationship between diffusion coefficients in the cracked concrete and the crack widths, service life of the cracked concrete is predicted in a probabilistic framework. A bimodal distribution with two peaks, consisting of a weighted sum of two normal distributions is introduced to describe chloride diffusion of the concrete wharf with crack.

• Smart Structures and Systems
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• 제26권2호
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• pp.241-251
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• 2020

Due to the undeniable importance of approximating the concrete compressive strength (CSC) in civil engineering, this paper focuses on presenting four novel optimizations of multi-layer perceptron (MLP) neural network, namely artificial bee colony (ABC-MLP), grasshopper optimization algorithm (GOA-MLP), shuffled frog leaping algorithm (SFLA-MLP), and salp swarm algorithm (SSA-MLP) for predicting this crucial parameter. The used dataset consists of 103 rows of information concerning seven influential parameters (cement, slag, water, fly ash, superplasticizer, fine aggregate, and coarse aggregate). In this work, the best-fitted complexity of each ensemble is determined by a population-based sensitivity analysis. The GOA distinguished its self by the least complexity (population size = 50) and emerged as the second time-effective optimizer. Referring to the prediction results, all tested algorithms are able to construct reliable networks. However, the SSA (Correlation = 0.9652 and Error = 1.3939) and GOA (Correlation = 0.9629 and Error = 1.3922) performed more accurately than ABC (Correlation = 0.7060 and Error = 4.0161) and SFLA (Correlation = 0.8890 and Error = 2.5480). Therefore, the SSA-MLP and GOA-MLP can be promising alternatives to laboratorial and traditional CSC evaluative methods.