• Journal of Aerospace System Engineering
• /
• v.16 no.1
• /
• pp.70-80
• /
• 2022

An aerial refueling provides for extension of operational time and range for aircraft and enhances mission effectiveness, hence it application by most military aircrafts. The receiver aircraft should have the aerial refueling clearance that is established by performing technical and operational compatibility assessments to certify it for aerial refueling with a specific tanker model. The compatibility assessment includes aerial refueling handling qualities, functional, fuel, lighting system testing and it is finally verified through flight testing. However, since aerial refueling compatibility assessments have never been performed in Korea, there is no experience to determine the test requirements and the scope and size of the test program for a new development aircraft. This paper therefore introduces the common techniques of aerial refueling and aerial refueling flight test methods to understand the aerial refueling FCS (Flight Control System), OFP (operational flight program) and system validation, and aerial refueling envelope clearance of a fixed wing aircraft for a boom and receptacle refueling system that is being introduced into Korea Air Force.

• The Journal of Society for e-Business Studies
• /
• v.16 no.4
• /
• pp.197-220
• /
• 2011

The smartphone is simply beyond the means of communication equipment, to line up the turning point of mobile convergence, is recognized as a service tool of new concept the camera, game, multimedia function, digital multimedia broadcasting, mobile internet etc, that use of smartphone is working toward developed a variety and new business models. The study is empirically studied casualties that self-determination influences flow and satisfaction which is intrinsic motivation of smartphone. There are many studies on flow, is intrinsic motivation, influencing satisfaction and Loyalty, but there are little studies which variables influences flow. this study is explore causality of autonomy, competence, relatedness which are major variables of self-determination theory that studied factors effecting intrinsic motivation influencing flow and satisfaction. This study developed a research model to explain the use of smartphone, and collected 670 survey responses from the office workers of seoul S company who had experiences with such smartphone. To prove the validity of the proposed research model, SEM analysis is applied with valid 670 questionnaires. The results, firstly, autonomy positively influences flow. secondly, competence significantly influences flow. thirdly, relatedness significantly influenced flow. also, upper above results shows that flow influences satisfaction.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.36 no.7
• /
• pp.759-768
• /
• 2012

This paper proposes a method to determine the elastic follow-up factors for the $C(t)$-integral under secondary stress. The rate of creep crack growth for transient creep is correlated with the $C(t)$-integral. Elastic follow-up behavior, which occurs in structures under secondary loading, prevents a relaxation of stress during transient creep. Thus, both the values of $C(t)$ and creep crack growth increase as increasing elastic follow-up. An estimation solution for $C(t)$ was proposed by Ainsworth and Dean based on the reference stress method. To predict the value of $C(t)$ using this solution, an independent method to determine the elastic follow-up factors for cracked bodies is needed. This paper proposed that the elastic follow-up factors for $C(t)$ can be determined by elastic-plastic analyses using the plastic-creep analogy. Finite element analyses were performed to verify this method.

• Journal of the Korean Geotechnical Society
• /
• v.28 no.3
• /
• pp.35-43
• /
• 2012

Following the companion paper (I. Comparisons with Well-known Seismic Code and Site Response Characteristics), several acceleration data recorded during recent earthquake events in Korea were analyzed to verify the suitability of the proposed two-parameters site classification system and the corresponding site coefficients. For all of rock-soil site pairs less than 30 km distant, response spectrums and corresponding site coefficients, $F_a$ and $F_v$, were determined. Unfortunately, some of data have an eccentric error, where the spectral acceleration of rock site is more amplified than that of soil site. The $F_a$ and $F_v$ for all of pairs except the pairs of error were compared with those in the current code and the proposed system. The $F_a$ and $F_v$ from the recorded motions show definitely different trend from that of the current code. In addition, the site coefficients from recorded motions at four 765 kV substation sites, which are several hundred meters distant, have a remarkably similar trend and absolute values to those in proposed two-parameters site classification system. Based on earthquake motions recorded in domestic areas including data from the four 765 kV substation sites, the two-parameters site classification and site coefficients are superior to the results obtained from the current Korean seismic code.

• Proceedings of the Korean Society for Rock Mechanics Conference
• /
• 2002.10a
• /
• pp.31-42
• /
• 2002

최근 지하철 터널은 사용자 편의성, 도심지 접근성 및 원활한 교통처리 등을 고려하여 지반조건이 불리한 상황에서도 터널로 계획되는 경우가 많아지고 있다 따라서 시공중의 터널안정성확보, 굴착에 따른 인접구조물의 침하영향, 발파진동영향 등을 종합적으로 고려한 지보패턴 및 보조·보강공법의 결정이 매우 중요하나 정량적인 판단기준의 부재로 인하여 주로 경험적인 설계에 의존하는 경우가 많다. 본 연구에서는 도심지 지하철 터널의 복합적인 거동특성을 고려하기 위하여 여러 가지 예상위험요소의 정량화 방안을 제안하고, 다변량 통계분석기법을 활용하여 여러 가지 위험 요소들의 특성을 함축적으로 나타내는 소수의 총합적인 지표(안정성인자, 환경성인자)로 대표화 할 수 있음을 검증하였다. 안정성 인자 및 환경성 인자를 이용한 서울시 지하철 00공구 설계사례를 통해 정량화지표(Multiple Index)의 터널설계에의 적용성을 평가하고 이의 설계시 활용방안을 제안하고자 하였다.

• Proceedings of the Korea Inteligent Information System Society Conference
• /
• 2007.11a
• /
• pp.564-569
• /
• 2007

자동화 컨테이너 터미널에서 안벽크레인, AGV(Automated Guided Vehicle)와 같은 하역장비의 작업은 수 많은 요인에 영향을 받으며, 이로 인해 각 장비의 작업시간을 정확하게 추정하는 것은 거의 불가능하다. 작업시간의 불확실성은 AGV 배차를 어렵게 만들고 작업효율을 떨어뜨리는 주요 원인이다. 본 논문에서는 이러한 불확실성에 대처하기 위하여 확률적 시뮬레이션 기반 AGV 배차 알고리즘을 제안한다. 제안 방안은 AGV를 배차할 때, 이후 일정 기간 동안의 AGV작업에 대해 확률적 시뮬레이션을 여러번 반복하여 수행하고 평가 값을 평균함으로써 불확실성의 영향을 줄인다. 확률적 시뮬레이션을 위해 크레인 작업시간의 불확실성을 간단한 확률함수로 모델링하고 그에 따라 크레인 작업시간을 결정한다. 또한 AGV 작업시간을 가감속, 간섭을 고려하여 추정한다. 시뮬레이션 실험을 통해 제안방안을 검증한 결과 안벽크레인의 지연이 감소함을 확인하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.36 no.2
• /
• pp.179-185
• /
• 2008

Simulating combustion tests have been performed to elucidate the effect of baffle gaps on the optimal damping characteristics in liquid rocket combustors where coaxial injectors are installed. Amplitude of pressure oscillation in model combustion chamber and the combustion stability margin are used to quantify the damping capacitance of baffles. Satisfactory agreement has been achieved with the results of cold acoustic tests. Present results have shown that the optimal gap for high acoustic damping capacity has also the large combustion stability margin in simulating combustion tests. Therefore, the present results can be utilized to determine the baffle length and optimal gap in full-scaled rocket combustors.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2012.05a
• /
• pp.945-945
• /
• 2012

본 연구에서는 낙동강 수계의 안동댐 유역을 대상지역으로 선정하여 미래 기후변화 시나리오에 따른 댐 유역의 수환경 영향을 예측해 보고자 하였다. 특히 미래기후에 대한 수환경 평가는 기후자료를 입력 값으로 요구하는 강우-유출모형을 이용하거나 유량 이외에 유사, 영양물질과 같은 수질인자를 동시에 모의할 수 있는 유역모형을 이용하여 평가하는 것이 일반적이다. 이를 위해 선행연구로 IPCC(Intergovernmental Panel on Climate Change)에서 제공하는 AR4 시나리오의 RCM 자료를 ANN(Artificial Neural Network)기법을 이용하여 안동댐 유역의 총 4개 기상관측소에 대한 과거 20년(1991~2010) 실측자료를 바탕으로 미래 강수 및 습도 그리고 온도에 대해 상세화 하여 미래 기후 시나리오를 생산하였다. 또한 안동댐 유역 단위의 수질을 예측하기 위해 토양과 토지이용 및 토지관리 상태에 따른 수문-수질 모의가 가능한 유역모형인 SWAT(Soil and Water Assessment Tool)을 이용하였다. 과거의 기상자료와 수질자료를 이용하여 유역모델의 검 보정을 실시하였으며 모형의 보정 및 검증결과에 따른 적합성과 상관성을 판단하기 위해 결정계수($R^2$)와 평균제곱근오차(Root Mean Square Error, RMSE)를 사용하였으며, 모형의 효율성 검증으로는 Nash and Sutcliffe(1970)가 제안한 모형효율성계수(NSE)를 사용하였다. 최종적으로 기후 시나리오에 대해서 전망된 지역상세기후를 유역모형의 입력자료로 이용하여 안동댐 유역의 미래수문 및 수질을 예측하고자 하였다.

• Journal of Distribution Research
• /
• v.7 no.1
• /
• pp.87-103
• /
• 2002

This study shows the effect of individual decision style on the Bullwhip effect of supply chain. There are four individual decision styles developed by Rowe and Boulgarides(1992). The analysis of the relationship between individual decision style and supply chain dynamics is focused on overshot against final consumer order rate. Multi methodologies are used to meet the goal of this study, which are survey, game and simulation. As a result of this study, the Bullwhip effect of supply chain isn't influenced by individual decision style. This study shows different result in comparision with the prior research results that individual fact affected the Bullwhip effect of supply chain, Therfore, it is important to improve supply chain infrastructure and system than the individual fact for decreasing the Bullwhip effect of supply chain.

• The Journal of the Korea Contents Association
• /
• v.15 no.9
• /
• pp.465-477
• /
• 2015

Today's companies build strong brand assets which, through the expansion of other business areas, promote efficient corporate management. Many companies manage brand assets among through a multitude of brand groups using brand portfolios rather than the single brand strategy. Such brand group influence can be related not only to brand group expansion, but also to parent company brands and product brand groups. The purpose of this study was to identify the effects of parent corporate brand associations on brand portfolio evaluation. The results of the present study is as follows: positive parent corporate brand image was revealed to play a positive role in brand portfolio evaluation. Parent corporate brand image provided endorsement for their product brands, and this can reduce consumer's decision cost on brand portfolio evaluations. This study focused on two types of brand relationship strategy : brand expansion strategy and individual brand strategy. With individual brand strategy, cases where parent company brands provided endorsement and cases to the contrary were studied separately. In cases where well-managed parent corporate brand image were able to provide endorsement in the case of individual brand strategy like that of brand expansion strategy.