• Aerospace Engineering and Technology
• /
• v.10 no.1
• /
• pp.89-97
• /
• 2011

This paper considers improved IGM (Iterative Guidance Mode), one of the explicit guidance algorithms, to determine the guidance algorithm for upper stages of a space launch vehicle. IGM, which has been employed successfully for the Saturn to put its payload into the parking orbit and lunar transfer orbit, is applied here for guidance of the launcher during the second and third stages. The orbit injection accuracy is evaluated through the 3-DOF computer simulations and an accurate prediction method, which can eliminate the prediction error of the downrange position at the orbit injection, is also proposed here.

• The Microorganisms and Industry
• /
• v.19 no.4
• /
• pp.62-67
• /
• 1993

의약품을 중심으로 한 광학활성 생리활성물질의 제조 즉, 정밀유기합성은 정밀화학의 꽃이라 할 수 있다. 이러한 광학활성물질은 통상의 유기화학적 수법으로 합성하면 라세미체로 얻어지고 광학활성체로 얻을 수 없다. 그래서 최근 chiral 중심을 가지는 간단한 화합물(광학활성합성원료-chiral building block, chiral synthon)을 원료로 해서 입체 선택적으로 반응을 조절함으로써 다양한 광학활성표적 화합물을 합성하는 방법이 활발히 진행되고 있다. chiral building block의 제조 방법을 살펴보기로하자.

• The Korean Journal of Nuclear Medicine
• /
• v.1 no.2
• /
• pp.27-34
• /
• 1967

1. Within experimental chromatin, the total protein: DNA ratio did not vary in the same organs of control and irradiated rats. However, the amount of RNA and total protein associated with the DNA varied considerably among the different types of chromatin. In particular, the content of chromatin was the highest in the irradiated tissue, and the lowest in the chromatin control tissue. RNA and total protein ratio of chromatins from brain, liver, testis and spleen declined with experimental organs. 2. There was the same quantitative relationship between the amount of RNA and the amount histone-protein associated with DNA in each chromatin. 3. RNA:DNA ratio of chromatin showed a $1.5{\sim}2$ times increase in the irradiated organs except brain. However, RNA:DNA ratio was decreased in chromatin by irradiation. 4. Histone-protein:Residual protein ratio was greatly varied among the organs. However, the effect was not found by irradiation. 5. Priming activity of chromatins showed a higher value in testis and the activity was greater in organs with higher metabolic activity. 6. Inhibition of Actinomycin D observable in chromatin for testis, liver, spleen and brain declined without relationship between irradiated and non-irradiated conditions. Ammonium sulfate in DNA of chromatin from histone showed increased priming activity with dissociation by Electrostatics. It may give different effect of ammonium sulfate on stimulation by property of chromatins. 7. It is suggested that the results support a proposal that the higher sensitivity of radioactive in testis, spleen by irradiated showed a increase and decrease lower-sensitivity of radioactive from brain, liver than did priming activity under the radioactive conditions.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.14 no.4
• /
• pp.321-328
• /
• 1989

The propagation characteristics of dielectric waveguides has been analyzed by finite element method. We have proposed the finite element formutation of the variational expression in the three-component magnetic field based on Galerkin's method which seek for the propagation constant by a given value of frequency. In this approach, the divergence relation for H is satisfied and spurious modes does not appear and finite element solustions agree with the exact solutions. In order to varify the validity of the present method the numerical results for a rectangular waveguide partilly filled with dielectric are compared with other results.

• Proceedings of the Acoustical Society of Korea Conference
• /
• spring
• /
• pp.237-240
• /
• 2002

지면에 가까이 있는 비행체나 수면에 가까이 있는 수중 운동체에서 도래하는 신호는 직접파와 반사파로 구성되어 있다. 그런 환경에서는 반사파가 직접파와 coherent한 관계를 갖는다. 이런 현상으로 해서 DOA추정을 위해 추정한 correlation 행렬이 singular한 성질을 갖게 된다. 이렇게 singular한 행렬은 DOA추정에 큰 오류를 내게 된다. 또 움직이는 대상의 경우 추정 correlation 행렬의 성질이 시간에 따라 변하게 된다. 본 논문에서는 위 두 상황을 함께 해결하기 위해서 PASTd알고리즘을 변형하여 Forward/Backward Variable forgetting factor를 도입한 PASTd알고리즘을 제안한다.

• 한국HCI학회:학술대회논문집
• /
• 2009.02a
• /
• pp.68-73
• /
• 2009

As various haptic algorithms and haptic equipments have developed, the computer simulation includes the haptic simulation. Basically, the haptic simulation requires very fast refresh rate approximately 1000 Hz. The traditional haptic simulations have satisfied that requirement by simplifying the target model. In soft body simulation, simplifying the deformation is not good because the visual feedback is important. Separating haptic model from deformable model can be solution of that problem. However, the user may feel a subtle distiction because the relationship between two models are not clear. In this paper, we propose the hybrid model to manipulate haptic rendering and deformation and define the relationship between two models.

• Journal of Information Management
• /
• v.6 no.6
• /
• pp.151-155
• /
• 1973

기업체(企業體)의 정보수요(情報需要)를 충족(充足)시킨다고 하는 것은 어느 국가(國家)에서나 대단히 어려운 문제(問題)이다. 새로운 발견(發見)의 적용발명(適用發明) 및 기술전달(技術傳達)은 단순(單純)한 문제(問題)가 아니며, 과학기술정보(科學技術情報)의 협동적(協同的)인 전달(傳達)도 또한 복잡(複雜)한 문제(問題)이다. 이유(理由)는 여러 가지이다. 즉 기업(企業)이라고 하는 것은 광범위(廣範圍)하고 복합적(複合的)이며 비교적(比較的) 비조직적(非組織的)이다. 기업(企業)의 임무(任務)는 생산(生産)이며 정보(情報)에 대한 기업(企業)의 인식(認識)은 퍽 낮기 때문이다. 기업체(企業體)에 정보(情報)를 제공(提供)하는 다양(多樣)한 외적(外的)인 서어비스는 대개 제공(提供)된 자료(資料)를 평가(評價)하지도 못하고 때로는 기업체(企業體)의 신임(信任)도 얻지 못하고 있다. 개발도상국(開發途上國)에 관(關)한 한(限) 기업(企業)의 성장(성장)에 대해 과학기술정보(과학기술정보)가 담당한 정확(정확)한 역할(역할)에 관(관)해서는 아직 불확실(不確實)하다. 정확(正確)한 정보수요(情報需要)를 정(定)하기에는 너무 많은 문제(問題)들이 있다. 즉 정보(情報)의 수요(需要)는 매우 복합적(複合的)인 과정(過程)임을 인정(認定)하여야 한다. 앞으로 개발도상국(開發途上國)들은 기술협력계획(技術協力計劃)에 의거(依據)하여 과거(過去)보다도 더 정보전달(情報傳達)에 역점(力點)을 두어야 하리라 생각한다.

• Bulletin of the Society of Naval Architects of Korea
• /
• v.6 no.2
• /
• pp.1-4
• /
• 1969

The added mass coefficients $K_2$ of two-dimensional cylinders of straightline-element sections for vertical viblation are presented as functions of parameters such as the beam-draf ratio B/H and the sectional area coefficient $\sigma$. The results are compared with those of Lewis forms and curvilinear-elements sections with single chine.

• Bulletin of the Society of Naval Architects of Korea
• /
• v.5 no.2
• /
• pp.1-26
• /
• 1968

This work is a general treatment of added mass calculation of two-dimensional cylinders with straight-framed sections and chines oscillating in the free surface of an ideal fluid with high frequencies. Two and three parameter families in vertical oscillations are treated by employing Schwarz-Christoffel transformation. The results are presented with regards to geometrical parameters such as chine engles, sectional area coefficient and beam draft ratio.

• Current Industrial and Technological Trends in Aerospace
• /
• v.7 no.2
• /
• pp.3-11
• /
• 2009

On August 25th, Korea launched KSLV-1(Naro), the first Korean launch vehicle with the payload of a small satellite. The launch itself was successful in that the first and second stage of the launch vehicle functioned properly but unfortunately the satellite was unable to be put into earth orbit due to the failure of a nose faring detachment. As the history of human space activities shows, it is recognized as a difficult task to be a launching state requiring efforts to obtain enough technical ability. But along with the technical ability, there has to be an understanding on international legal systems on space launch vehicle. It is because the launch may cause cross-border losses and because the launcher is regarded as a strategic technology resulting in international control. This paper aims to study the international status of launching state and to consider legal regimes necessary for launcher development.