• 항공우주시스템공학회지
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• 제13권6호
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• pp.70-79
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• 2019

매년 증가하는 항공기 조류충돌 사고는 현행 항공기 조류충돌 인증 요구도의 보완을 요구한다. 현재 미국과 유럽에서는 수치해석을 통해 조류충돌 요구도를 더욱 정밀하게 검증하는 방안을 검토 중이다. 한편 국토교통부에서 고시한 항공기 감항기준은 미국 연방항공청에서 제정한 감항기준에 준하여 작성되었다. 이는 국내 규정에서도 해석 기반의 조류충돌 요구도 검증 방안이 반영되어야 함을 의미한다. 본 논문에서는 한국항공우주산업(주)의 경찰청 헬리콥터 외부 보조연료탱크 조립체를 대상으로 유한요소 해석에 기반한 조류충돌 분석기법을 제안하였고, 해석 결과는 시험 결과에 상응하였다. 이에 따라 수치해석 기반의 분석기법과 절차가 조류충돌 요구도 뿐만 아니라, 나아가 다른 감항요건의 입증에도 폭넓게 활용되도록 제안하고자 한다.

• Safety and Health at Work
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• 제7권4호
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• pp.347-353
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• 2016

Background: This study aimed to investigate the relation between key strike forces and musculoskeletal symptoms (MSS). Moreover, this study presents a key strike force measurement method to be used in a workplace setting. The correlation between key strike force characteristics and MSS was previously studied, but the measurement methods used either a single-key switch or force platforms applied under the keyboard. Most of the studies were conducted in a laboratory setting. The uniqueness of measurement methods in the current study is their ability to measure forces applied to a specific key in a workplace setting and to provide more information about specific key strike forces during typing. Methods: Twenty-four healthy computer workers were recruited for the study. The demographic questionnaire, and self-reported questionnaires for psychosocial status (General Nordic Questionnaire for Psychological and Social Factors at Work) and for detecting MSS were filled up, which later helped in dividing the participants into two groups (12 participants with pain and 12 without pain). Participants typed a predetermined text that utilized the instrumented keys multiple times. The dynamic forces applied to the keys were recorded and collected, using four thin and flexible force sensors attached to the preselected keys according to their location. Results: The results demonstrated that participants with high levels of MSS, specifically in the back and neck, in the last year exerted significantly higher key strike forces than those with lower levels of symptoms (p < 0.005). Conclusion: The key strike force exerted while typing on a keyboard may be a risk factor for MSS, and should therefore be considered in ergonomic evaluations and interventional programs.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 추계학술대회 논문집 전력기술부문
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• pp.139-141
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• 2007

차단기, 단로기와 간은 개폐기는 투입 동작이 이루어질 때, 접점 간의 내전안과 양단간의 전안차 사이의 관계에 의하여 pre-strike 현상이 발생한다. 따라서, 개폐기가 투입되는 동안 발생하는 과도철상을 파악하기 위해서는 개폐기의 pre-strike 친상을 모델링하는 것이 중요하다. 본 논문에서는 개폐기의 pre-strike 현상을 EMTP로 모델링하고 이를 모델 계통에 적용하여 구현된 pre-strike 모델이 타당함을 보였다.

• 경영과학
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• 제25권1호
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• pp.55-74
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• 2008

In recent warfare, the performance improvement of air weapon systems enables an aircraft to strike multiple targets on a single sortie. Further, aircrafts attacking targets may carry out an operation as a strike package that is composed of bombers, escort aircrafts, SEAD (Suppression of Enemy Air Defenses) aircrafts and etc. In this paper, we present an aircraft allocation model that allocates multiple targets to a single sortie in the form of a strike package. A mixed integer programming is developed and solved by using a commercially available software. The new model is better than existing ones because not only it allocates aircrafts to multiple targets but also it models the concept of the strike package. We perform a computational experiment to compare the result of the new model with that of existing ones, and perform sensitivity analysis by varying a couple of important parameters.

• Communications for Statistical Applications and Methods
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• 제11권2호
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• pp.213-225
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• 2004

A fixed-strike lookback option is an option whose payoff is determined by the maximum (or minimum) price of the underlying asset within the option's life. Under the Black-Scholes framework, the time-t price of an equity asset follows a geometric Brownian motion. Applying the method of Esscher transforms, this paper will derive explicit pricing formulas for fixed-strike lookback call and put options, respectively. In addition, this paper will show a relationship (duality property) between the pricing formulas of the call and put options. Finally, this paper will derive explicit pricing formulas for the fixed-strike lookback options when their underlying asset pays dividends continuously at a rate proportional to its price.

• 응용통계연구
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• 제21권3호
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• pp.485-495
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• 2008

A floating-strike lookback call option gives the holder the right to buy at the lowest price of the underlying asset. Similarly, a floating-strike lookback put option gives the holder the right to sell at the highest price. This paper will present explicit pricing formulas for these floating-strike lookback options with flexible monitoring periods. The monitoring periods of these options start at an arbitrary date and end at another arbitrary date before maturity. Sections 3 and 4 assume that the underlying assets pay no dividends. In contrast, Section 5 will derive explicit pricing formulas for these options when their underlying asset pays dividends continuously at a rate proportional to its price.

• 한국군사과학기술학회지
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• 제19권2호
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• pp.177-184
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• 2016

This paper presents a strike velocity estimation using the recursive Bayesian filter that operates both correction and prediction models to probabilistically remove noises of sensors and accurately estimate the strike velocity during the real-time experiments. Four different types of bullets such as 5.56 mm M193, 7.62 mm M80, 5.45 mm 7N10 and 7.62 mm MSC were used to validate the proposed method. Compared to the existing method, the proposed method statistically results in higher stability of the strike velocity estimation as well as its reliability for the ballistic limit velocity computation.

• ETRI Journal
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• 제42권1호
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• pp.46-53
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• 2020

Gait analysis is an effective clinical tool across a wide range of applications. Recently, inertial measurement units have been extensively utilized for gait analysis. Effective gait analyses require good estimates of heel-strike and toe-off events. Previous studies have focused on the effective device position and type of triaxis direction to detect gait events. This study proposes an effective heel-strike and toe-off detection algorithm using a smart insole with inertial measurement units. This method detects heel-strike and toe-off events through a time-frequency analysis by limiting the range. To assess its performance, gait data for seven healthy male subjects during walking and running were acquired. The proposed heel-strike and toe-off detection algorithm yielded the largest error of 0.03 seconds for running toe-off events, and an average of 0-0.01 seconds for other gait tests. Novel gait analyses could be conducted without suffering from space limitations because gait parameters such as the cadence, stance phase time, swing phase time, single-support time, and double-support time can all be estimated using the proposed heel-strike and toe-off detection algorithm.

• 자원환경지질
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• 제28권1호
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• pp.69-77
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• 1995

Tertiary Pohang basin distributed in south western part of the Korean peninsula, is composed of Chunbuk formation as the basal conglomerate, Hakjon formation, Duho formation and intrusive basalt having 15 Ma by absolute age data. The basement of the basin is represented to Cretaceous sedimentary rocks, Hakjon welded tuff and Chilpo welded tuff and rhyolite. The fault systems in the basement of Tertiary Pohang basin are consist of $N20^{\circ}E$ fault, $N60^{\circ}W$ and E-W trend. NNE fault is not only strike-slip but also normal dip-slip. WNW fault has sinistral strike-slip sense and the geometry of E-W fault is strike-slip and normal faults. In the basin, the fault system is represented to $N20^{\circ}E$ strike-slip, E-W normal and NNE thrust faults. By these fault relationship and geometry, it is interpreted that NNE sinistral strike-slip fault and N-S normal faults have acted at the Cretaceous basement. After Miocene NNE dextral strike-slip fault has acted and created E-W normal fault. Progressively Tertiary basin was influenced by the transpression to make thrust and fold, namely inversion tectonics.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제28회 춘계학술대회논문집
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• pp.67-70
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• 2007

항공기 엔진 흡입구는 개발시에 조류 충돌에 대한 충분한 안전성을 검토하여 설계되어야 한다 항공기의 속도가 점차 증가함에 따라 FOD(Foreign object damage)에 따른 항공기의 사고가 증가하고 있다. 특히 이착륙시 활주로 주변 새들에 의한 항공기 사고는 경제적 손실을 비롯해 탑승객의 생명과 연결되는 중요한 문제이다 본 연구에서는 유한 요소 상용 코드인 MSC/DYTRAN을 이용해 엔진 흡입구 낫셀 구조에 대한 조류 충돌 해석을 수행하였다. 해석 결과의 타당성 검증을 위해 선행 연구 결과와 비교한 후 조류 충돌 해석 결과의 거동을 분석하였다.