• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전력기술부문
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• pp.118-120
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• 2001

This paper presents a distance relaying algorithm based on the Discrete Fourier Transform(DFT) for elimination of DC-Offset. When the DFT is applied to current signal. the real and imaginary parts of fundamental component consist of fundamental component itself and DC-Offset. The DC-Offset is calculated by four consecutive values of the imaginary components, so that the fundamental component can be accurately estimated. Performance evaluation is presented for A-phase ground faults on 154kV 80km overhead transmission line. The proposed algorithm is inspected by software simulation and hardware simulation.

• 한국식품저장유통학회지
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• 제9권4호
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• pp.396-399
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• 2002

An attempt was made in this study to investigate the optimum extracting time from meat with bone of goat and the nutritional component of its extract. for the trials, the mixtures of meat with bone and water were adjusted to the ratios of five to four by weight and extracted for 6, 9 and 12 hours at 120$\^{C}$ under autoclave. Judging from the content of mineral and amino acid, nonenzymatic browning and yield, the optimum extracting time was 9 hours. The major components of mineral were composed of 47.7mg％ potassium, 12.7mg% calcium, 150.0mg% sodium, 105.3mg% phosphorus and 0.5mg% iron, and of amino acids composed of 1,308.0mg% glutamic acid, 1,464.2mg% glycine, 750.2mg% alanine and 828.lmg% proline in extract. The yield of extract was 32.1 percentage by dry basis.

• 한국항공운항학회지
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• 제20권3호
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• pp.35-43
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• 2012

Medium size rotorcraft consist of approximately 5,000 key components. The components must satisfy the target weight and performance requirement through optimization. Therefore a rotorcraft component has approximately 100 times higher unit cost for mass production than the equivalent of an automobile's, along with huge development cost. Configuration management consists of four main parts : configuration identification, configuration control, configuration audit, and data management. In development programme, configuration management is one of the methods to save development cost, and setting a well-structured configuration management system according to the Military Standard is an important factor in success of the programme. The paper proposes a configuration management system suitable for development of various multi-use components development and presents that the configuration management was performed successfully during dual-use component development programme using the established system.

• 동력기계공학회지
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• 제6권1호
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• pp.27-35
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• 2002

In this paper, the effect of oxygen component in fuel on the exhaust emissions has been investigated for direct injection diesel engine. It is tested to estimate change of engine performance and exhaust emission characteristics for the commercial diesel fuel and oxygenate blended fuel which has four kinds of mixed ratio. And, the effects of exhaust gas recirculation(EGR) on the characteristics of NOx emission and brake specific fuel consumption rate have been investigated. Dimethyl carbonate(DMC) contains oxygen component 53.3% in itself, and it is a kind of effective oxygenated fuel of carbonate group that the smoke emission of DMC is reduced remarkably in comparison with commercial diesel fuel, that is, it can supply oxygen component sufficiently at higher loads and speeds in diesel engine. It was found that simultaneous reduction of smoke and NOx was achieved with oxygenated fuel and EGR method.

• 농업과학연구
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• 제8권2호
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• pp.139-151
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• 1981

육종재료(育種材料)를 얻기 위해 수집(蒐集)된 한국(韓國) 재래종(在來種) 옥수수 57계통(系統)에 대(對)하여 주성분(主成分) 분석(分析)을 적용(適用)하여 재래종(在來種) 옥수수르 해석(解釋)하고 계통분류(系統分類)를 하였던 바 다음과 같은 결과(結果)를 얻었다. 1. 27개(個) 형질(形質)을 이용(利用)하여 실시(實施)한 주성분(主成分) 분석(分析)에서 제(第)4 주성분(主成分)까지를 가지고 전변동(全變動)의 67.09% 설명(說明)할 수 있었고, 제(第)1주성분(主成分)까지를 취(取)하면 전변동(全變動)의 88.63%를 설명(說明)할 수 있었다. 2. 형질(形質)의 주성분(主成分)에 대(對)한 기여율(寄與率)은 형질(形質)과 주성분(主成分)에 따라 큰 차이(差異)가 있었다. 3. 주성분(主成分)과 형질문(形質問)에 상관계수(相關係數)는 주성분(主成分)의 생물학적(生物學的) 의의(意義)와 주성분(主成分)에 대응(對應)한 식물체의 type을 명확(明確)히 하였다. 4. 계통간거리(系統間距離)에 의(依)해 57계통(系統)을 4개(個)의 계통군(系統群)으로 분류(分類)하였다.

• 대한기계학회논문집A
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• 제34권6호
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• pp.771-780
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• 2010

본 논문에서는 제작이 용이한 십자형 구조를 기본구조로 사용하여 판스프링 고정단을 가진 유연한 6축 로드셀을 설계하였다. 이를 위하여 유한요소법해석을 이용하여 강체 고정단과 판스프링 고정단에 대한 변형 분석을 하였으며 이로부터 특성이 우수한 6축 힘/토크 센서를 설계하였다. 변형률 분포를 이용하여 각 축의 하중에 대한 출력변형률이 비슷한 수준이 되도록 스트레인 게이지 위치를 정하고 상호간섭 변형률이 최소화 되도록 이들로 연결된 브리지회로를 구성하였다. 강체 고정단 대신에 스프링판 고정단을 이용하면 고정 경계부의 조건을 변화시킬 수 있어서 십자형 로드셀의 특성을 획기적으로 개선시킬 수 있었다. 치수 변경을 통하여 설계된 6축 로드셀에 대한 상호 간섭오차는 모든 축에서 0으로 계산되었으며 각 축에서 발생하는 출력변형률 값도 $400\;{\mu}m/m$의 비슷한 수준으로 결정되었다.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2000년도 추계 기술심포지움 논문집
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• pp.89-92
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• 2000

테입 캐스터를 이용하여 바인더/가소제, 글말함량 비율이 다른 LTCC 테입을 제작한 후 특성평가를 하고자 하였다. 슬러리 조성은 서로 다른 바인더/가소제 그리고 분말함량에 따라 각각 4개 조성으로 구성하였다. 모든 슬러리에서 발포나 핀홀이 없는 미려한 표면을 갖는 테입을 얻을 수 있었다. 가장 우수한 기계적 특성 특성은 B/P=3.0, 분말함량 70vo1%인 두께 52 $\mu\textrm{m}$인 테입에서 인장강도 4.6MPa, 신을 29.5%의 특성을 얻을 수 있었다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제15권4호
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• pp.233-240
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• 2015

We analyse reliability of multi-state UH-60 helicopter hydraulic pump system with a multi-functional standby component using Markov analysis method. The system consists of seven components: 2 main pumps, 1 standby pump, 2 primary servos, and 2 tail rotor servos. The standby pump can take over when one more than components fail. Therefore the standby pump is multi-functional standby component. The system has four states: good, deteriorated, dangerous, and failed. The components have 2 states: working and failed. We assume the system is unrepairable when the components fail. We estimate failure distributions and rates using collected failure time data in field. And we classify multi-state of the system according to emergency procedure of UH-60A student handout. We obtain the reliabilities of multi-state system using Visual Basic program because the differential equations is extremely complicated and tedious to solve.

• 한국대기환경학회지
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• 제18권1호
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• pp.25-37
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• 2002

The purpose of the study was to survey the distribution patterns of inorganic elements of PM-10 in the various indoor environments and analyze the pollution patterns of aerosol in various places of indoor environment using a pattern recognition method based on cluster analysis and disjoint principal component analysis. A total of 40 samples in the indoor had been collected using mini-vol portable samplers. These samples were analyzed for their 19 bulk inorganic compounds such as B, Na, Mg, Al, K, Ca, Ti, V, Cr, Fe, Ni, Cu, Zn, As, Se, Cd, Ba, Ce, and Pb by using an ICP-MS. By applying a disjoint principal component analysis, four patterns of the indoor air pollutions were distinguished. The first pattern was identified as a group with high concentrations of PM-10, Na, Mg, and Ca. The second pattern was identified as a group with high concentrations B, Mg, At, Ca, Fe, Cu, and Ba. The third pattern was a group of sites with high concentrations of K, Zn. Cd. The fourth pattern was a group with low concentrations PM-10 and all inorganic elements. This methodology was found to be helpful enough to set the criteria standard of indoor air quality, corresponding pollutants, and classification of indoor environment categories when making an indoor air quality law.

• 천문학회지
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• 제19권1호
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• pp.33-49
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• 1986

Radial distribution of internal density has been determined for thirteen subclouds in the three giant molecular cloud complexes accompanying Mon OB1, Mon OB2 and CMa OB1 associations, We modeled their radial density structures with the density distribution of isothermal gas spheres. Most of the subclouds, nine out of the thirteen, are well described by isothermal spheres of single component; while the rest four require an additional component. Total mass and potential energy of each subcloud are also derived from the radial density structure; thermal energy and internal velocity dispersion required for sustaining the density structure are deduced from the isothermal gas model. Our derived masses of the clouds are comparable to the values determined by Blitz (1978) under LTE assumption. This agreement suggests that the correction factor for non-LTE effect on mass-estimate is not far from unity. The ratio of the gravitational potential energy to the kinetic energy of thermal motion is as large as 250; hence the thermal motion alone cannot support these clouds against the gravity. Being supported by turbulence motion with velocities of six to seven times the thermal velocity, the clouds of one-component type seem to be in equilibrium with the gravity; while the clouds of two-component type are likely to be in the stage of gravitational collapse.