• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.23-24
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• 2021

The use of recycled concrete aggregates (RCA) as a substitute for natural aggregates in new concrete produces both economic and environmental advantages. Most of the RCA applications for pavements have been primarily applied to support layers for roads and airfields. This paper summarizes a work completed at the University of Illinois in partnership with the O'Hare Modernization Program to examine the effect of coarse and fine RCA on the concrete's fresh and hardened properties for airfield rigid pavement applications. Ten different RCA concrete mixtures were prepared with the incorporation of different percentages of RCA fines as well as replacement of cement with high volume percentages of supplementary cementitious materials such as Class C fly ash and ground granulated blast furnace slag to improve the workability and long-term properties of RCA concrete. All the mixes on this stage included 100% recycled coarse aggregates and the Two-Stage Mixing Approach was used as a mixing procedure. Based on the results obtained in the research, mixes with high percentages of recycled fine and coarse aggregates could be used for construction of airfield concrete pavements in conjunction with supplementary cementitious materials

• Journal of Korean Society of Transportation
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• v.30 no.5
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• pp.83-90
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• 2012

Driver ordinarily takes sudden braking when urgent situation is developed or when the vehicle is involved in an unexpected accident. Therefore, the most common trace at a traffic accident scene is skid mark. Currently, in investigating traffic accident, overspeed is determined by the length of skid mark. However, in order to identify accurate cause of accident, estimation of pre-braking speed which takes into account speed reduction during transient time should be considered as a requirement. In a recent study, several ways to estimate pre-braking speed were suggested, but none considered to differentiate the decelerating transient brake section and skidding section. This study analyzed trends of decelerating transient brake section and skidding section by real braking test.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.30 no.3
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• pp.95-102
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• 2018

As a recent technical approach, a high-speed planing hull was tried to realize a friction reducing system by simultaneously actuating the triple streamlined step hull form in association with optimum speed of 35 knot planing for fishing boat. In this approach, the streamlined step hull form with triple structure of type was attached under the bottom of high-speed planing hull, while a friction resistance is reduced in the process of running at the speed of 35 knot. In addition, this research was to make a performance test as to the manufactured product and acquire the purposed values and the development items. Actually, after manufacturing the desired prototype of high-speed planing hull, the significant items, fuel efficiency (second) and amount of fuel consumption (degree) including maximum speed (knot) were estimated for a performance test. And tensile strength (MPa) and bend strength (MPa) as to the completed prototype like a high speed planing hull were also acquired during the test.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.28 no.2
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• pp.29-35
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• 2020

In this paper, we established a prediction model of fuel consumption at the aircraft's taxi operation. To look for countermeasures to reduce fuel consumption and carbon emissions, Airbus A380's actual ground taxi data was used. As a result, the number of stops or turnings during the taxi operation was not related to fuel consumption. It was confirmed that the amount of fuel consumption in the taxi operation was the taxi time and the thrust change. It can be confirmed that ground control optimization, which is the result of close cooperation between the control organization and the airline, is absolutely necessary to reduce taxi time and minimize the occurrence of thrust change events.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.34 no.3
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• pp.283-286
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• 1998

For the systematic study on the resistance characteristics of the planing hull, the experimental studies on the correlation between geometrical characteristics of the subject hull forms and their hydrodynamic characteristics are carried out. This study is the first stage to develop the advanced planing hull type fishing boat and involves the followings; -Resistance characteristics for typical four different section types, -Resistance characteristics for different length-beam ratio

• Journal of the Korean Society for Aviation and Aeronautics
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• v.24 no.3
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• pp.48-54
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• 2016

This paper proposes a prediction model of air traffic controller's take-off clearance under mixed mode runway operations. The proposed model has its purpose on the better prediction of the air traffic controller's clearance on take-offs of departure aircraft by considering various factors. For this purpose, support vector machine classification algorithm is used for the proposed model. The proposed model is applied to real air traffic operations to demonstrate its performances.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.14 no.4
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• pp.110-119
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• 2006

This research was conducted with a view to enhance the efficiency of the preventive tool which provide pilots and controllers with proper and timely safety alerts while conducting circling approach at the airport where surrounding terrains becomes threat to safe operation of flight around airport.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.11a
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• pp.216-217
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• 2018

소형 활주선의 경우, 대형 저속선 대비 항주자세의 변화가 크기 때문에 CFD 해석시 저항성능과 운동성능 결과에 오차가 발생할 수 있다. 본 연구에서는 Warped 2 선형을 대상으로 상용 CFD 코드인 STAR-CCM+ v9.04를 사용한 CFD해석을 수행하여, 이를 모형시험 결과와 비교하여 오차를 확인하였고, 또한 오차의 원인을 분석했을 때, 선체 하부의 Numerical ventilation 현상과 Spray 영역에 문제가 있다고 판단하였다. 추후 연구에서는 오차 해결 방법으로 VOF Phase replacement 기법과 Spray 영역에 대한 격자 최적화 방법을 연구하고자 한다.

• Current Industrial and Technological Trends in Aerospace
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• v.5 no.1
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• pp.93-103
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• 2007

3차원의 공간을 비행하는 항공기의 항행은 조종사가 직접 지상의 지형지물을 참조하며 비행하는 시각비행과 지상의 항행안전시설로부터 무선신호를 받아 비행하는 계기비행으로 구분되어 발전되었다. 현재 계기비행을 수행하기 위한 계기비행절차 수립에 기반이 되는 항행안전무선시설은 기존의 VOR(VHF Omni-directional Range), ILS(Instrument Landing System) 등의 지상기반 항행안전무선시설에서 GNSS (Global Navigation Satellite System)를 이용한 위성기반 항행으로 전환을 목표로 하고 있으며 항행체제 또한 기존의 Fix to Fix 항행체제에서 RNAV(Area Navigation) 체제로 전환되고 있는 추세이다. 계기비행절차는 항공기가 활주로를 이륙하여 항로로 진입하기 위한 계기출발절차(SID), 항로절차(Enroute), 항로에서 목적 공항의 지정된 활주로에 설정된 접근절차(Approach)로 인도하는 도착절차(STAR), 지정된 활주로에 착륙하기 위한 접근절차로 구분될 수 있으며 본문에서는 GNSS를 기반으로 하는 RNAV 절차(RNAVGNSS)에 대한 개괄적인 소개, 설계요건 및 RNAVGNSS 계기비행절차를 성공적으로 이행하기 위한 절차이행모델, RNAVGNSS 절차 수립에 중요하게 고려해야할 사항 등에 대하여 소개하도록 한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.11a
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• pp.1051-1052
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• 2023

조류충돌(Bird Strike)은 경제적 손실, 인명적 피해를 야기하여 공군의 항공작전을 제한하는 위협요소이다. 현 공군에서는 조수퇴치조(Bird Alert Team)의 경보 발령에 의존하거나 조류의 행동을 연구하는 등 인적 역량에 의존하는 시스템을 채택하고 있다. 본 연구는 CNN을 이용하여 활주로의 유해조류를 인식 및 분류하는 자동화 시스템에 대한 제안이다. 웹캠을 활용한 실시간 유해조류를 인식하는 연구를 통해 향후 운항관제대와의 연계, 지향성 조류퇴치 장비와의 연동 방안을 제시하여 공군의 조수퇴치조(Bird Alert Team)에 대한 자동화를 실현하고 공군에서 추진중인 스마트 비행단에 이바지하고자 한다.