• 한국추진공학회지
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• 제24권1호
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• pp.1-8
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• 2020

메탄/산소 이원추진제 소형로켓엔진의 성능평가를 위한 형상설계 및 시험평가시스템을 구축하였다. 인젝터는 추진제 미립화 성능이 우수하고, 연소불안정성이 적은 스월 동축형(swirl-coaxial) 방식을 채택하였다. 연소효율 비교를 위해 연소실의 종횡비는 1.5, 1.8, 2.1로 각각 설정하였다. 그리고 정밀추력측정장치의 측정 신뢰성을 높이기 위해 pre/post calibration을 실시하였다. 그 결과, 예비 지상연소시험에서 추력과 비추력은 89.2 N, 181.8 s로 78.4%의 효율을 가지고, 특성속도는 84.2%의 효율을 갖는 것이 확인되었다.

• 품질경영학회지
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• 제21권1호
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• pp.55-64
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• 1993

This article is concerned with procedures for detecting one or more outliers or influential observations in a linear regression model. A test procedure, based on recursive residuals is proposed and developed The power of the test procedure to identify one or more outliers is investigated through simulation, and its relevance to the number and configuration of the outlier.

• 한국축산시설환경학회지
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• 제21권1호
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• pp.9-20
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• 2015

The livestock manure recycling have been performed worldwide because of its environmental and economic benefits. However, domestic standard protocol was nothing for high solid manure. Therefore, This paper was conducted to review database configuration of manure characteristics, analysis methods, bio-methane potential test for high solid manure recycling. In American society of agricultural engineers standard, manure characteristics indicated about sort of thirty types. This is important information to determine for manure recycling method. Furthermore, in order to determine exact manure characteristics recommended that synchronized chemical analysis method among studies. Bio-methane potential tests are widely performed in studies about estimation of organic substrates methane production. Although various methods and parameters were used, was no standard protocol and guideline in domestic. Bio-methane potential test methods and parameters were reviewed through various researches. Consequently, this paper is expected that assist to additional studies and manure characteristic database.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권11호
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• pp.520-526
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• 2006

Corona interferences, such as radio noise, audible noise and television noise, need to be taken into account in the design of HVDC transmission line conductor configuration. Therefore the line designer requires data from which to estimate the corona performance of any set of conductors. To get a sufficiently complete set of design data, it is necessary to examine the corona test of a large number of conductor geometries. This paper presents the results of corona cage test among three types of candidate conductors. It is quite clear from test results that the conductor geometries play an important role in establishing the magnitude of corona noise. Corona noise data from corona cage test are expressed as a statistical distribution of results obtained over long periods of time and various weather conditions. Therefore we can determine an environmentally-friendly conductor bundle for HVDC overhead transmission line. Based on this finding results, various simulations about HVDC line configurations, such as pole space and pole height, will be conducted. And then finally an optimal configuration for HVDC transmission line will be decided.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 추계학술대회 논문집
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• pp.578-585
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• 2000

ATC/ATO/TWC System is the used for the train operation instead of drivels. It is interfaced with train, train equipment, wayside facilities. In this paper described configuration signaling system, construction of signaling system software and structure of system safety. This paper describes the method of performing automatic driving by ATC/ATO/TWC. Also, reported test result for mainline static test and mainline running test.

• 항공우주기술
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• 제4권1호
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• pp.31-38
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• 2005

체공형 부양선인 Aerostat에 대한 개념설계를 수행하였다. 기존의 풍동 시험자료를 참조하여, 정적 종안정성을 확보하기 위한 Aerostat의 외형 설계를 수행하였다. 주어진 동체형상과 길이에 대한 표면적 및 부피는 Cubic Spline을 이용하여 수치적으로 계산하였고, 반복계산을 통하여 동체의 길이를 결정하였다. 개념설계를 위한 케이블 장력과 중량, 그리고 임무장비 무게를 산정하였다. 중량과 임무고도 등과 같은 중요한 설계 변수에 대한 민감도를 분석하였으며, 그 결과로서 30m급의 Aerostat 시스템에 대한 개념 설계결과를 제시하였다.

• 한국자동차공학회논문집
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• 제9권1호
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• pp.171-180
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• 2001

Collision accident reconstruction algorithm are developed based on the deformation shape and severity of a car body. At first, the body stiffness equation representing the force-deformation relationship is derived using finite element analysis for head on collision of two cars. The database of deformation shapes and energies is constructed for five different collision configurations; each configuration contains three velocity conditions. Deformation shapes are obtained using a curve fitting method and result in cubic polynomials. Deformation energies are calculated using a stiffness equation and deformation data. Three algorithms are developed to reconstruct collision configuration compared with constructed database. The developed algorithms show reasonably good performance to find collisions conditions for some test problems.

• Journal of Mechanical Science and Technology
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• 제20권12호
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• pp.2087-2093
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• 2006

In this paper, auto focus actuator, which is used to move a lens module in the mobile phone having a camera module, is developed. Camera module containing auto focus actuator requires to minimize total size because of characteristics of the application area such as mobile phone, digital camera, and personal digital assistant. There are stepping motor, voice coil motor, and piezoelectric motor as auto focus actuator. In this paper, voice coil motor having new electromagnetic configuration is proposed. And actuator using proposed voice coil motor is developed by optimal design method using magnetic circuit analysis. The sectional area of the developed actuator is reduced to 32.4% compared with actuator using general electromagnetic configuration. From the performance test, the developed actuator has moving stroke of 0.64 mm for 2.1 volt, hysteresis of 40 $\mu$m, full stroke current of 54 mA, and unit step motion of 3 $\mu$m.

• 한국항공운항학회지
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• 제20권4호
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• pp.31-38
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• 2012

In this paper, requirements of GNSS receiver station installation are derived for optimizing the performance of network based GNSS precise positioning by concern of international organization(IGS, NGS) recommendation. Also a analysis method of network based GNSS precise positioning is suggested in order to evaluate the availability depending on various network configurations. To evaluate network candidates, a performance evaluation method is proposed for positioning of users according to a geometric configuration and the baseline distance. After the proposed method is used to Ochang region that is a the test area 6 network candidates are derived and the performance of positioning was analyzed. Finally, Ansung, Gongju, Eumsung, Boeun network configuration was selected as the best positioning performance. An optimal Receiving station network was selected using the proposed method.

• International Journal of Aeronautical and Space Sciences
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• 제6권2호
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• pp.33-45
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• 2005

The 1/9-scale model of a fighter-type configuration was tested in the Micro-Craft 8ft ${\times}$ 12ft wind tunnel facility. An abrupt lift dump was found at a certain range of angle of attack under the pre-scheduled approach configuration. To avoid a probable unsatisfactory flight behavior due to the lift dump, various aerodynamic devices were suggested. Extensive tests applying the cutoff leading edge flaps, boundary layer fences, saw tooth and vortex generators were performed with flow visualization as well as force and moment measurements. Test results showed that the origin of the lift dump was caused by the secondary boundary layer flow separation generated from the strong interaction between wing and flap. Various solutions for avoiding the unfavorable feature were suggested with the merits and demerits.