• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2006년도 제27회 추계학술대회논문집
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• pp.135-138
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• 2006

가스발생기 사이클 엔진시스템 설계를 입력값과 기본 요구값으로 나누어 설계 요구값을 만족하기 위한 설계변수 11개를 정의하였다. 이 11가지의 설계변수를 통하여 설계 요구값을 만족하기 위한 압력 유량 파워 균형 관계식 11개를 제시하였으며, Newton 방법을 이용하여 해를 찾는 프로그램을 제작하였다. 고안된 프로그램을 이용하여 가스발생기 사이클 엔진의 시스템설계를 수행하여 그 유효성을 입증하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권5호
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• pp.2186-2203
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• 2020

Security administrators of companies and organizations need to come up with proper countermeasures against cyber-attacks considering infrastructures and security policies in their possession. In order to develop and verify such countermeasures, the administrators should be able to reenact both cyber-attacks and defenses. Simulations can be useful for the reenactment by overcoming its limitations including high risk and cost. If the administrators are able to design various scenarios of cyber-attacks and to develop simulation models from their viewpoints, they can simulate desired situations and observe the results more easily. It is challenging to simulate cyber-security issues, because there is lack of theoretical basis for modeling a wide range of the security field as well as pre-defined basic components used to model cyber-attacks. In this paper, we propose a modeling method for cyber-security simulations by developing a basic component and a composite model, called Abstracted Cyber-Security Unit Model (ACSUM) and Abstracted Cyber-security SIMulation model (ACSIM), respectively. The proposed models are based on DEVS(Discrete Event systems Specification) formalism, a modeling theory for discrete event simulations. We develop attack scenarios by sequencing attack behaviors using ACSUMs and then model ACSIMs by combining and abstracting the ACSUMs from a security perspective. The concepts of ACSUM and ACSIM enable the security administrators to simulate numerous cyber-security issues from their viewpoints. As a case study, we model a worm scenario using ACSUM and simulate three types of simulation models based on ACSIM from a different security perspective.

• 대한조선학회 특별논문집
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• 대한조선학회 2013년도 특별논문집
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• pp.66-72
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• 2013

The demand for an ice class ship is rising expected to rise according to the increase of energy consumption and the opening of arctic sea routes. Ice class ship should be designed to cope with the severe environmental conditions of arctic sea such as a high mechanical impact and abrasion damage, caused by pack ice, ice bergs and low temperature. The ice class ship hulls are coated with an anti-abrasion and low friction coating such as a solvent free epoxy or high solid-volume epoxy. These coatings require two-component heating pump and a high grade surface preparation. In this study, the coating performances for the arctic vessels, such as puncture absorbed energy, abrasive wear loss, friction coefficients and impact absorbed energy were evaluated. Based on this study, a proper coating performance specification for the arctic vessels was proposed and coating selection guideline in terms of coating performance and workability was also established.

• 품질경영학회지
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• 제24권3호
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• pp.145-159
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• 1996

In today's organization, measurement plays a crucial role in helping improve process or quality. In this paper, we review the measurement error study, classical gauge repeatability and reproducibility study, and designed experiment suited for the determination of the measurement capability. Measurement error study is very simple to use but is rather crude. Hence, it should be used as a preliminary study to determine whether further study is necessary. Classical gauge repeatability and reproducibility (GR&R) study is the most common technique for evaluation of gauge capability. It calculates a percentage that relates the repeatability, reproducibility, and overall R&R to the specification range for the parameter measured. Hence, the individual repeatability and reproducibility statistics will indicate the area on which to concentrate. However, GR&R study only gives a point estimate of each component, which leaves a room for improvement. It is always good to integrate the use of control charts to ascertain the statistical stability of the measurement process. The tools of statistical experimental design are available for a comprehensive design and analysis of the measurement process. Hence, in this paper, we present gauge capability analysis as an experimental design problem and compare it with the classical GR&R study.

• 한국멀티미디어학회논문지
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• 제11권9호
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• pp.1277-1285
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• 2008

본 논문에서는 WiMAX 와 HSDPA 모드를 모두 지원하는 SCA 기반 다중모드 SDR 단말의 컴포넌트를 설계하고 블럭도를 제시하였으며, 실제 실험을 통한 경량화 대상 분석을 통해 SDR 단말 구현 시 어느 구성요소를 경량화해야 하는 지 분석해 보았다. 또한, 컴포넌트 재구성 분석을 통하여 동적 재구성 전체 시간 측정을 위한 일반 식을 도출하였고, 분석 결과를 토대로 SCA 규격의 인터페이스와 수행절차를 위배하지 않는 범위 안에서 총 22단계에 걸친 컴포넌트 레벨 동적 재구성 알고리즘을 설계하였다.

• 한국항행학회논문지
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• 제9권2호
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• pp.121-130
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• 2005

본 논문에서는 항공관제용 VHF대역 무선 송신기 설계 제작에 관하여 연구하였다. 연구된 무선 송신기의 기본적인 성능은 기존 상용화된 관제용 무선 송신기의 사양을 만족하도록 설계 제작하였으며, 전력 증폭부의 교체만으로 출력 전력 25 W와 50 W가 모두 가능하고 AM 변조로 음성을 전송하는 것을 기본으로 한다. 본 논문에서 연구된 항공관제용 무선 송신기는 크게 4개의 모듈 즉, 전원부, 제어부, 저출력 송신부, 전력 증폭부로 구성되어 있으며, 전력 증폭부를 장착하지 않으면 1 W급 송신기로 동작하게 설계되었다. 연구된 항공관제용 무선 송신기는 CNS/ATM의 기본 요소로 사용되기에 충분한 시스템이라고 판단된다.

• 소성∙가공
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• 제25권4호
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• pp.268-274
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• 2016

In the automotive seat industry, the use of a fine blanking press is important for manufacturing of high precision products. Among them, a gear part which is a main component of an automotive seat recliner is generally manufactured by fine blanking press. However, the use of conventional mechanical press has been increasing in manufacture of gear part because of low productivity of fine blanking press. In this study, new forming process is suggested to fabricate the gear part with high precision by using mechanical press. The effect of flow restriction die (FRD) which has the restriction of blank edge on dimensional accuracy is investigated by FE-analysis. FE-analysis results for different conditions of FRD indicated that FRD has high dimensional accuracy with the lowest roll-over and the highest perpendicularity of gear part. After application to fabrication of the gear part using mechanical press, the measured dimensional characteristic was compared with the required specification of final product. In addition, results of the performance test showed that the product fabricated by developed process satisfied the required strength and durability. The results show that the suggested forming process by using FRD and mechanical press can replace fine blanking on the viewpoint of dimensional accuracy and productivity.

• KDI Journal of Economic Policy
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• 제31권1호
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• pp.1-25
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• 2009

본 논문은 일반적인 뉴 케인지언 이론의 주요 특징을 바탕으로 하는 동태적 확률 일반 균형 모형을 설정하고 이를 바탕으로 하여, 베이지안 추정법을 통해 한국의 자연 산출량과 자연 이자율의 추정을 시도하였다. 본 논문의 주요 결과는 다음과 같다. 첫째, 이러한 이론 모형에 의해 추정된 산출량 갭은 기존의 일반적인 접근법에 의한 추정치보다 변동 폭이 훨씬 작은 것으로 나타났다. 둘째, 다양한 모형 설정을 통해 결과의 민감도를 살펴본 경우, 필립스 커브에서의 과거 지향적 요인 및 소비 행태에서의 습관 형성 등이 한국 거시경제의 동태적 양상을 설명하는 데 중요한 요인일 수 있는 것으로 나타났다.

• 대한조선학회논문집
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• 제49권5호
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• pp.433-439
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• 2012

Anticorrosive paint is the most widely used in shipbuilding and the dry film thickness is very important in terms of productivity and assurance of anticorrosive performance. However, it is difficult to achieve the recommended target film thickness because the dry film thickness depends on labor's skill in practice and is affected by a number of parameters, such as spray pressure, paint flow rate, tip size, spray distance, SVR(Solid Volume Ratio), etc. Present paper derives an empirical equation through the correlation analysis of parameters selected by spray experiments of anti corrosive painting in order to predict the coated status. Comparing the calculated results with practical data, we show that the empirical equation can successfully expect DFT(Dry Film Thickness).

• 한국철도학회논문집
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• 제14권5호
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• pp.411-415
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• 2011

DC/DC컨버터는 임의의 직류전원을 부하가 요구하는 형태의 직류전원으로 변환시키는 전력변환기이다. 전압모드 DC/DC 컨버터는 주기적으로 입력측에서 출력측으로 전달되는 에너지를 제어하는 기능을 수행하기 위해 MOSFET(산화물-반도체 전계 효과 트랜지스터), 인덕터, PWM 제어기(오실레이터, 연산증폭기, 비교기로 구성)를 이용한다. 본 논문에서 PWM(펄스폭 변조) 모듈과 스위칭모드로 제어하는 기본적인 승압과 강압컨버터를 연구하고, 전기적 특성을 SPICE로 시뮬레이션을 수행하며, 전력의 효율을 각 소자의 변화와 사양에 따라 분석하는데 있다.