• Journal of Aerospace System Engineering
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• v.13 no.6
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• pp.70-79
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• 2019

The increase of bird strike requires to be amended more safely current airworthiness requirements for bird strike. The USA and Europe are considering the methodology to verify the bird strike requirements based on the finite element analysis (FEA). Meanwhile, the aircraft airworthiness standards in Korea enacted by the Ministry of Land, Infrastructure and Transport were based on those enacted by the Federal Aviation Administration (FAA). This means that the verification methods using the FEA for the bird strike requirements should be reflected in the airworthiness standards in Korea. Our study proposes the methodology for bird strike simulation based on the FEA for the external auxiliary fuel tank assembly on the Surion helicopters and confirmed that the numerical outputs corresponded to the test results. The authors suggest that the methodology and procedure based on the FEA are adopted not only in the bird strike requirements but in various aircraft certifications of civilian rotorcraft.

• Safety and Health at Work
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• v.7 no.4
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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.

• Proceedings of the KIEE Conference
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• 2007.11b
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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.

• Korean Management Science Review
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• v.25 no.1
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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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• v.11 no.2
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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.

• The Korean Journal of Applied Statistics
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• v.21 no.3
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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.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.2
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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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• v.42 no.1
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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.

• Economic and Environmental Geology
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• v.28 no.1
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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.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.67-70
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• 2007

It is well known that the aircraft engine inlet should be safely designed against the bird strike at the aircraft development stage. The aircraft accident is increasing for FOD(Foreign Object Damage), especially bird of runway circumference. The aircraft accident due to bird strike brings about economic loss and which is connected with the life of passengers. In this study, MSC/DYTRAN has been utilized to analyze the aircraft engine inlet against the bird strike. In order to validate the proposed method for the bird strike analysis, this study was performed with comparison of precedence study results.