• International Journal of Internet, Broadcasting and Communication
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• 제12권4호
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• pp.1-10
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• 2020

Safety can be defined as being maintained or reduced to a level below which the possibility of human or physical harm can be tolerated through continuous identification of risks and safety risk management. FAA, EASA, IATA and Boeing, major organizations that conduct research and analysis for aviation safety around the world, report that about 70 percent of aviation accidents are caused by human factors, which have led to a surge in interest in human factors-induced accident prevention activities around the world. As part of this purpose, the FAA in the U.S. is raising awareness among aviation workers by publicizing the 12 human errors (Boeing, 2016), which account for the largest part of aviation accidents under the theme of Dirty Dozen, to prevent aviation accidents. Therefore, based on the domestic helicopter accidents reported to the Air Railroad Accident Investigation Committee from 2007 until recently, this study aims to use HFACS to extract human factors for the six recent helicopter accidents in Korea, analyze the extracted human factors in conjunction with the Dirty Dozen concept, and then present measures to prevent accidents by item.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.914-920
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• 2002

Nonlinear flow-induced vibration characteristics of a generic missile wing (or control surface) are investigated in this study. The wing model has freeplay structural nonlinearity at its pitch axis. Nonlinear aerodynamic flows with unsteady shock waves are considered in the transonic flow region. To practically consider the effects of freeplay structural nonlinearity, the fictitious mass method (FMM) is applied to structural vibration analysis based on a finite element method (FEM). A computational fluid dynamics (CFD) technique is used for computing the nonlinear unsteady aerodynamics of all-movable wings. The aerodynamic analysis is based on the efficient transonic small-disturbance aerodynamic equations of motion using the potential-flow theory. To solve the nonlinear aeroelastic governing equations including the freeplay effect, a modal-based computational structural dynamic (CSD) analysis technique based on fictitious mass method (FMM) is used in time-domain. In addition, CSD and unsteady CFD techniques are simultaneously coupled to give accurate computational results. Various aeroelastic computations have been performed for a generic missile wing model. Linear and nonlinear aeroelastic computations have been conducted and the characteristics of flow-induced vibration are introduced.

• 한국항공운항학회지
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• 제29권3호
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• pp.44-51
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• 2021

PIP is an abbreviation of 'Performance Improvement Package', which is a package that can improve performance by applying some design changes to existing aircraft. Boeing provides PIP applicable to B777-200, and Airbus provides PIP applicable to A350-900 as standard. PIP provided by Boeing and Airbus is a separate task, but it is expected to reduce fuel consumption by reducing drag through aerodynamic improvements. The PIP applied to the A350-900 includes work such as increasing Winglet Height and re-twisting Outboard Wing. This study is to verify the effect of PIP application of the A350-900 aircraft and use it as basic data for economic analysis. The aerodynamic improvement studies and expected effects of the PIP application were examined, and the actual flight data of the PIP-applied and the non-applied aircraft were compared to confirm the PIP application effect. This paper provides empirical results for the aviation industry on the PIP application efficiency as a method of improving fuel efficiency and reducing carbon emission.

• 한국전산구조공학회논문집
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• 제24권6호
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• pp.715-722
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• 2011

본 논문에서는 항공기 충돌에 의한 원전 격납건물의 거동을 병렬해석을 통해 수행하였다. 지금까지의 원전 격납건물에 대한 항공기 충돌관련 연구는 항공기의 경우, Riera의 충격하중-시간함수를 이상화하여 대상 구조체의 일정영역에 대해 충격하중으로 적용하는 방법을 사용해 왔고 충돌대상 구조체의 경우, 단순 철근콘크리트 벽체나 빌딩에 머물러 왔다. 하지만 본 논문에서는 항공기(Boeing-767, http://www.boeing.com)와 가상의 원전 격납건물을 실제와 유사하게 모델링하여 해석을 수행하였으며, 항공기모델은 충돌평가 가이드인 NEI 07-13(2009)에서 허용하는 Riera의 식에 따른 충돌하중이력곡선과 비교하는 방법으로 검증되었다. 또한, 일반적으로 고속 충돌해석은 짧은 시간동안 두 개 이상의 물체가 접촉하고 동적 대변형을 일으키는 비선형성이 강한 문제로 많은 계산시간이 요구되기 때문에 이를 효과적으로 다루기 위해서는 단일 CPU만으로는 한계가 있다. 따라서 본 논문에서는 해석의 효율성을 향상시키기 위해 자체 구축한 리눅스 클러스터 시스템을 이용하여 Message-Passing MIMD 형태의 병렬해석을 수행하였고 병렬성능에 대한 평가를 위해 무근콘크리트(Plain Concrete, PC), 철근콘크리트(Reinforced Concrete, RC), 내부 Liner Plate를 부착한 철근콘크리트(RC with Containment Liner Plate, CLP), SC구조(Steel-Plate Concrete, SC)등 4가지 경우에 대한 수치해석 효율성이 비교 검토되었다.

• 한국전자거래학회:학술대회논문집
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• 한국전자거래학회 1998년도 학술대회지 vol.1
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• pp.57-68
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• 1998

ㆍ STEP is an International Standard (ISO 10303) - that defines the methodology to create computer interpretable product data models. ㆍ STEP Implementation - allows exchange and sharing of product data while retaining semantics throughout the product life cycle. ' STEP is in deployment - PDM data exchange at Boeing and others - Geometry data exchange at GM and others ㆍ The STEP community overcomes obstacles - “They will never finish the standard” (done 1994) - “They will never be able to transfer solids” (done 1995) - “They will never make solids transfer reliable” (done 1997) - “They will never implement all those Application Protocols”(TBD)(omitted)

• 한국통신학회논문지
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• 제31권11B호
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• pp.997-1004
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• 2006

인터넷을 기반으로 하는 IT 눈부신 발전과 더불어 언제, 어디서나, 시간과 장소에 구애받지 않고 인터넷을 사용할 수 있도록 하는 사회적 요구가 구체화 되고 있다. 이러한 요구에 부응하고자 국내에서는 시속 200km이상의 빠른 속도로 이동 중에 있더라도 초고속인터넷이나 방송 서비스를 제공할 수 있는 위성광대역 인터넷 시스템기술을 개발하고 있다. 본 연구에서는 위와 같이 개발된 시스템을 국내 고속철도(KTX)에 적용하여 서비스를 제공할 때, 관련 시설투자에 대한 경제적 타당성을 검토하고i라 한다. 경제성 분석을 위해 현재 유럽에서 이미 제공되고 있는 고속철도 인터넷서비스를 조사하였고, 국내 고속철의 특성을 감안하여 필요시설과 장비를 구성하여 항목별 비용분석을 수행하였다. 해외 사례와 비행기 등의 다른 운송수단에서 예상하고 있는 수요 및 요금 수준에 근거하여 고속철도 인터넷서비스 매출을 시나리오별로 전망하였으며, 각 시나리오에서 계산된 비용과 매출로부터 순현재가와 수익률을 산정 하였다. 본 연구의 결과는 관련 기술 개발에 대한 경제적 타당성 여부를 판단하는데 활용될 수 있으며, 비용효과적인 서비스 설계 및 구현에 도움을 줄 수 있을 것으로 기대된다.

• 한국전자파학회논문지
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• 제26권2호
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• pp.218-225
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• 2015

역합성 개구면 레이더(Inverse Synthetic Aperture Radar: ISAR) 영상은 표적으로부터 반사되어 돌아온 레이더 수신신호들을 코히런트하게 신호처리하여 형성한 표적의 2차원 영상이다. 본 논문에서는 계단 첩 파형(Stepped Chirp Waveform: SCW)을 이용한 ISAR 영상 형성과정에서 펄스 간 움직임(Inter-Pulse Motion: IPM)이 존재하는 경우, 이를 효과적으로 보상하기 위한 알고리즘을 제안한다. 널리 쓰이는 최적화 기법 중 하나인 particle swarm optimization(PSO)를 기반으로 IPM에 관련된 표적의 속도와 가속도를 추정한다. 또한, 개선된 PSO를 통해 기존의 성능을 더욱 향상시켜 실시간 요동보상을 수행한다. 시뮬레이션에서는 Boeing-737의 점 산란원 모델을 이용한 기동 시나리오에서 제안된 알고리즘의 성능을 확인한다.

• Nuclear Engineering and Technology
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• 제53권5호
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• pp.1686-1704
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• 2021

This study addresses the numerical simulation of the shield building of an AP1000 nuclear power plant (NPP) subjected to a large commercial aircraft impact. First, a simplified finite element model (F.E. model) of the large commercial Boeing 737 MAX 8 aircraft is established. The F.E. model of the AP1000 shield building is constructed, which is a reasonably simplified reinforced concrete structure. The effectiveness of both F.E. models is verified by the classical Riera method and the impact test of a 1/7.5 scaled GE-J79 engine model. Then, based on the verified F.E. models, the entire impact process of the aircraft on the shield building is simulated by the missile-target interaction method (coupled method) and by the ANSYS/LS-DYNA software, which is at different initial impact velocities and impact heights. Finally, the laws and characteristics of the aircraft impact force, residual velocity, kinetic energy, concrete damage, axial reinforcement stress, and perforated size are analyzed in detail. The results show that all of them increase with the addition to the initial impact velocity. The first four are not very sensitive to the impact height. The engine impact mainly contributes to the peak impact force, and the peak impact force is six times higher than that in the first stage. With increasing initial impact velocity, the maximum aircraft impact force rises linearly. The range of the tension and pressure of the reinforcement axial stress changes with the impact height. The perforated size increases with increasing impact height. The radial perforation area is almost insensitive to the initial impact velocity and impact height. The research of this study can provide help for engineers in designing AP1000 shield buildings.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3039-3044
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• 2007

A few fluid structure interaction analyses have been developed for turbomachinery blades in comparison with aircraft wings. Also, the existing aeroelastic analyses for turbomachinery blades have been mostly limited to cases with a steady freestream. In reality, however, the inflowing freestream is often pulsating. Therefore, this paper presents stability and forced response analyses of an isolated three-dimensional blade under pulsating freestream conditions. A new three-dimensional unsteady vortex lattice model under a pulsating freestream has been developed in discrete time domain to examine unsteady aerodynamic forces acting on a vibrating blade. The blade's structural behaviors have been analyzed by using a three-dimensional plate model. In the aeroelastic analysis, the flutter onset of a blade under pulsating freestream is predicted by the Floquet analysis. The new time domain method can predict aeroelastic stability as well as time history.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2857-2861
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• 2007

Flow and aerodynamic characteristics were analyzed numerically for a commercial passenger airplane, Boeing 747-400, flying in the cruising condition. The model geometry with 100:1 in scale was obtained by the photo scanning measurement with the maximum error of 1.4% comparing with the real airplane dimension. The three-dimensional inviscid steady compressible governing equations were solved by the finite volume method in the unstructured grid system. The convective terms were treated by the Crank-Nicholson and first-order upwind schemes. In the computational results, the strong wing-tip vortices were clearly observed and the pressure contours on the airplane surface were suggested. The lift and drag forces in the wing with engines increase by 1.49% and 3.9%, respectively compared with the case without engines. The aerodynamic forces were estimated quantitatively for each element which consists of the airplane.