• The Journal of Engineering Geology
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• v.7 no.1
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• pp.81-90
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• 1997

The Korean historical 1iteratures describe that great eaathquakes with destructive damages occurred mainly in Kyongju-Ulsan areas during the period of 1 to 8 century and 16 to 17 century. It seems that the Ulsan fault system shows a little curved ttend with N-S strike in the southern part and diverges into three directions from the mid-northern lart of the fault. The dominant trends of the lineaments are NNE-SSW, NE-SW and NS directions. Trench excavation in the mid-northern part of the Ulsan fault shows thrust facies cutting slope deposit containing a compacted laminar structure whose origin may due to severe cryogenic activities of the last cold period(ahout 25OOO B.P.). Detailed observation of the facies gives some evidences related to two earthquake episodes of thrust components along the Ulsan fault system. Fault outcrop and trench study suggest that Ulsan fault seems to he one of the active fault which has reworked several times even in the late Quaternary.

• Journal of Internet Computing and Services
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• v.3 no.4
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• pp.37-50
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• 2002

XML document repositary system(XDRS) should be able to manage vertical and horizontal versions of documents to store, update and manage XML documents without loss of information, However, most of existing XDRSs do not support a versioning method Although a few systems support versioning method. they only manage vertical versions of XML documents, While the vertical versioning preserves the update history of documents. the horizontal versioning branches a document to many other versions of documents so that users can easily create new documents from the original version and edit them to have different meanings. In this paper, we propose a new version numbering scheme to support both vertical and horizontal versioning efficiently. We also design a schema that supports versioning and preserves the paradigm of structure information.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.107-110
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• 2009

A basic design for a Technical Development Model (TDM) of liquid oxygen lines from the turbopump exit to the oxidizer valves of the combustion chamber and the gas generator was conducted to develop a turbopump-fed liquid rocket engine. The TDM is composed of straight lines, elbows, bellows, a branch, an orifice, flanges and a heat insulator. Materials were determined by consideration of operation conditions, weight constraint and manufacturing procedures. The size and the location of each component were determined by flow analysis of the required flowrate and the pressure loss. Basic designs of the components were conducted by consideration of the operating temperature and the maximum expectation operating pressure. The safety factors were evaluated by structural analysis of design of each component.

• Journal of the KSME
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• v.35 no.7
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• pp.603-609
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• 1995

요즘 우리의 경제는 선진국의 호경기와 개도국의 고성장 지속 및 초엔고의 영향으로 산업전반에 걸쳐 커다란 호황을 누리고 있다. 이 덕택에 국내 산업의 수출량은 전년도에 비해 30% 이상 증가하여 1분기 현재 수출은 262억 달러에 달하고 있으나, 수입은 더욱 늘어나 무역수지는 40억 달러의 적자를 보이고 있다. 이러한 무역수지 적자의 가장 큰 원인은 수출이 증가하면 할수록 그 기본적인 기자재(기계류, 부품, 소재)를 외국, 특히 일본으로부터 수입해야 하는 우리의 선업구 조의 취약성 때문이다. 따라서 모처럼 맞이한 엔고의 호기에 우리의 경제는 적자의 부담만 가 득안고, 우리의 노력으로 얻은 수익의 대부분을 남의 호주머니에 넣어주는 결과를 초래하고 있는 상황이다. 이를 해결하기 위해서는 무역적자의 근본원인이 되고 대일 의존성향이 강한 기계류, 부품, 소재 등 자본재 산업의 국산화를 통한 우리 산업의 구조적 체질개선, 즉 기술 자립이 필 수적이다. 이러한 관점에서 '87년부터 추진하고 있는 기계류, 부품, 소재의 국선화계획의 의의를 알아보고 이것이 가지는 문제점과 대책에 대해서 알아보는 것은 상당한 의미가 있을 것이다. 최근의 엔고는 '80년대 후반 엔고시대 이후 2번째 맞이하는 절호의 기회로서, 너무 근시안적인 이익에만 급급해 하지 말고 장래에 얻을 수 있는 효과를 극대화하기 위한 투자가 필요한 시기 임을 깨닫고 우리의 근본문제와 대책을 다시 한 번 검토해 볼 수 있는 좋은 기회로 삼아야 할 것이다.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.4
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• pp.106-112
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• 1997

We demonstrate a novel wavelength -division add/drop multiplexer employing fiber bragg gratings and polarization beam splitters. the multiplexer is easy to fbricate without any special technique such as UV trimming, and yet shows very stable performance with less than 0.3-dB crosstalk power penalty in a 0.8-nm-spaced, 2.5Gbps-per-channel WDM transmission system. We find that the rejection of adjacent channels is more than -6dB, and the signal leakage through output port is less than -34dB.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.132-132
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• 1999

카본 박막은 내마모성, 내산성, 윤활성 및 높은 경도를 가지고 있어, 경질 박막 및 기능성 박막으로 주목을 받고 있으며 그 응용 분야가 매우 크다. 본 연구는 전자빔(Electron Beam)을 카본 grain을 증발시킴과 동시에 아르곤 보조 이온빔을 조사시켜 이온에너지에 따른 박막의 물성변화를 관찰하였다. 특히 본 연구에서 이용한 이온빔 증착 장치의 장점은 이온 충돌 에너지의 조절이 가능하다는 것이다. 카본 박막의 제조는 이온빔이 증착된 고진공 증착 장치를 이용하였고 이원빔원으로는 Oxford Applied Research 사의 RF 방전형 이온빔을 이용하였다. 배기장치는 유회전펌프와 터보펌프를 사용하였다. 기판은 홀더에 장착하기 전에 전처리를 거친 후 용기 내에서 이온빔에 의해 2차 청정을 하였다. 빔전압이 500V, 빔 전류는 4mA/cm2 및 RF power를 400W로 하여 기판 청정을 거친 후 전자빔을 이용하여 흑연을 증발시켜 박막을 제조하였다. 이때 이온빔 전압을 100~500V, RF power를 400~550W 으로 조절하였다. 카본 grain을 Si 및 Slide Glass 기판위에 1$\AA$/sec의 증착율을 유지하면서 증착하였다. 카본 박막의 박막은 평균두께는 0.3~0.4$\mu\textrm{m}$이며 SEM을 이용하여 단면을 관찰하였다. 라만 분광분석을 통하여 비정질 카본 박막의 결합특성을 조사하였고 scratch tester를 이용하여 박막의 밀착력을 관찰하였다. 그리고 카본 박막의 전도도 특성을 알고자 비저항을 측정하였으며, 박막의 성분 분석을 위한 AES 분석을 하였다. 1)AES 결과:표면에서와 박막 내부에서는 불순물인 산소나 질소의 함량이 거의 존재하지 않음을 관찰하였다. 2)경도:1,000~1,400kg/mm2 3)라만 분광 분석:300V의 이온 에너지를 분기로 박막 구조의 변화에 의한 스팩트럼의 변화를 보였다. 4)비저항:10-2~10-1$\Omega$.cm

• Journal of Life Science
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• v.11 no.5
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• pp.400-404
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• 2001

A new human endogenous retroviral family (HERV-S) has recently been identified from human X chromosome. It is 6.7 kb in length and has a typical retroviral structure with LTR-gag-pol-env-LTR. Using the PCR and sequencing approach, we investigated LTR elements of the HERV-S family from a human genomic DNA. Four LTR elements (HSL-1, HSL-5, HSL-10, HSL-11) were identified and have a high degree of sequence similarity(96-99%) with that of the HERV-S. Phylogenetic analysis from the HERV-S family indicated that the LTR elements were mainly divided into 2- groups through evolutionary divergence in the primate evolution. Further investigation of the HERV-S LTR elements in primates may cast light on the integration timing into the primate genome and understanding of human evolution.

• Journal of the Society of Naval Architects of Korea
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• v.36 no.2
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• pp.94-104
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• 1999

Plate buckling is very important design criteria when the ship is composed of high tensile steel plates. In general, the plate element contributes to inplane stiffness against the action of inplane load. If the inplane stiffness of the plating decreases due to buckling including the secondary buckling, the flexural rigidity of the cross section of a ship's hull also decreases. In these cases, the precise estimation of plate's behaviour after buckling is necessary, and geometric nonlinear behaviour of isolated plates is required for structural system analysis. In this connection, the author investigated the geometric nonlinear behaviour of simply supported rectangular plates under uniaxial compression in the longitudinal direction in which the principle of minimum potential energy method is employed. Based on the energy method, elastic large deflection analysis of isolated palate is performed and simple expression are derived to discuss the bifurcation paint type buckling and limit point type buckling.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.6A
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• pp.547-555
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• 2006

We implemented DPU(Double-Pass Gain-Clamped) L-band EDFA for highly efficient amplification. A lasing signal generated within the linear cavity, can minimize the fluctuation of surviving channels when several WDM(Wavelength Division Multiplexing) channels are added or dropped. The new method measuring the characteristics of transient response of surviving channels quantitatively is suggested. It is to measure the ratio of lasing output before add or drop to that after add or drop. We investigated dynamic characteristics by using this method according to lasing wavelengths and propagation directions within the cavity. Experimental measurements show that the short lasing wavelength and backward propagation direction is the best condition for small fluctuation of surviving channels.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.694-698
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• 2005

The operation speed improvement of the train in electric railway must pursue continuously and need the investigation of whole railway system whole. The high-speed of the train is related to not only vehicle technique but also the infrastructure, signal system, operation technique, the trolley line and catenary, economical efficiency. Specially, in case of electric railway, we have to consider a technical investigation which is current collection efficiency improvement, voltage drop countermeasure, equipment capacity, track force, signal system. In this paper, we presents the technical investigation of AT feeder system in order to achieve high speed train in exist real railroad. We proved this approach which will use the whole domestic lines in the future.