• 통상정보연구
• /
• 제8권3호
• /
• pp.121-142
• /
• 2006

Recently regarding the ownership and proper operational forms of paperless trade infrastructure has become an issue. In this research the structural separation approach, different from the behavioral regulation approach, has been adopted. Following the structural separation, the core e-trade infrastructure which is separated from a vertically integrated provider, can be operated by three different forms such as a private sector; a public sector; finally a consortium among participants. As another option, the separated whole infrastructure including both core and non-core can be operated by a independent private entity. However, this option is not interesting case to us. As the last option, it can be considered that a new wholesale independent company for the separated core-infra can be set up for running. Additionally, three other alternative ways such as accounting separation, division separation, or corporation separation with keeping same ownership are also demonstrated. However the cautious investigation on cost and benefits of vertical separation are strongly recommended by OECD and agrees with the conclusion of this study.

• 한국철도학회논문집
• /
• 제12권6호
• /
• pp.844-851
• /
• 2009

본 논문에서는 수직분리 및 수직통합의 경험이 함께 존재하는 유럽철도의 자료를 기존연구에서 사용된 바 없는 Simar and Wilson(2008)의 붓스트랩을 활용한 효율성에 관한 가설검정방법으로 분석하여 수직분리가 철도산업의 운영효율성과 어떤 관련성을 가지고 있는지를 밝혀보고자 하였다. 1998년부터 2005년까지의 20개 유럽국가의 자료를 분석한 결과 검정통계량의 관측값은 수직분리구조를 가진 국가의 철도산업이 수직통합구조를 가졌거나 또는 지주회사의 형태로 수직통합을 유지하고 있는 국가의 철도산업보다 상대적으로 운영효율성이 높게 타나났으나 그러한 차이가 통계적으로 뒷받침되지는 못하였다.

• 한국정보통신학회논문지
• /
• 제18권8호
• /
• pp.2051-2056
• /
• 2014

함정의 탈자결과 평가를 위한 자계신호의 분리방법에 대한 이론적 근거와 해저 면에 설치되는 사각코일로부터 발생하는 불균일한 자계가 분리결과에 미치는 영향을 측정 신호와 FEM해석을 통해 검토하였다. 측정신호는 제작된 모델함에서 발생하는 자계를 자계센서로 측정한 것이며 FEM 계산은 제작된 모델함과 동일한 형상으로 수행되었다. ILM(induced longitudinal magnetization) 신호와 IVM(induced vertical magnetization) 신호는 함정이 가지는 투자율과 지자계의 수평과 수직방향 성분에 의해 각각 발생하는 자화에 의한 것이며, PLM(permanent longitudinal magnetization) 신호와 PVM(permanent vertical magnetization) 신호는 함정의 영구자화의 수평성분과 수직성분에 의한 것임이 확인되었다. 또한 사각 코일의 수직방향의 자계는 균일한 지자계를 완전히 상쇄할 수 없어 사각코일의 면적에 가까운 크기를 가지는 함정 일수록 사각코일의 자계 불균일성의 영향을 크게 받게 됨을 알았다.

• Geomechanics and Engineering
• /
• 제5권3호
• /
• pp.223-240
• /
• 2013

In the present study an attempt was made to predict the complex nonlinear parameters of the soil-pile system subjected to the vertical vibration of rotating machines. A three dimensional (3D) finite element (FE) model was developed to predict the nonlinear dynamic response of full-scale pile foundation in a layered soil medium using ABAQUS/CAE. The frequency amplitude responses for different eccentric moments obtained from the FE analysis were compared with the vertical vibration test results of the full-scale single pile. It was found that the predicted resonant frequency and amplitude of pile obtained from 3D FE analysis were within a reasonable range of the vertical vibration test results. The variation of the soil-pile separation lengths were determined using FE analysis for different eccentric moments. The Novak's continuum approach was also used to predict the nonlinear behaviour of soil-pile system. The continuum approach was found to be useful for the prediction of the nonlinear frequency-amplitude response of full-scale pile after introducing the proper boundary zone parameters and soil-pile separation lengths.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
• /
• pp.435-440
• /
• 2006

The Reduced Vertical Separation Minimum (RVSM), which is the reduced minimum from 2,000 ft to 1,000 ft at flight levels (FL) between 290 and FL410 inclusive, was implemented in 30 September 2005 within the Japanese domestic airspace. Prior to the implementation, safety assessment for the airspace in assumed RVSM environments was carried out. Some model parameter values of collision risk model were estimated using flight plan (progress) data and radar data. An estimate of vertical collision risk including operational risk was calculated using these together with given parameter values. The results obtained from this analysis are as follows. (1) Contribution of the vertical collision risk for the crossing routes is about 9 percents of the total technical risk. (2) The estimate of the collision risk is $4.1{\times}10^{-9}$ [fatal accidents / flight hour] and the value is smaller than a maximum allowable level of collision risk, i.e. $5{\times}10^{-9}$ [fatal accidents / flight hour], called the Target Level of Safety.

• Journal of Advanced Marine Engineering and Technology
• /
• 제27권6호
• /
• pp.721-727
• /
• 2003

Freezing of turbulent water flow between two horizontal cooled parallel plates with the separated region has been investigated experimentally. The flow separation was induced by vertical plates (two-dimensional plates) situated at the inlet of the rectangular channel. The degree of flow separation was varied by employing vertical thin plates with various heights. Three kinds of the vertical plates with 8.0, 9.8 and 12.5 mm in height were utilized. The Reynolds number and cooling temperature ratio were ranged from $3.45\times10^3 to 1.73\times10^4$ and 7.0 to 20.0 respectively, The measurements show that the flow separation influenced remarkably on the local ice formation characteristics. The location of the first ice layer and the average heat transfer at the ice surface were found be correlated as a function of the Reynolds number, the cooling temperature ratio, and the orifice height ratio.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제7권3호
• /
• pp.177-182
• /
• 2007

This paper presents the see-saw type RF MEMS switch based on a single crystalline silicon structure with narrow gap vertical comb. Low actuation voltage and high isolation are key features to be solved in electrostatic RF MEMS switch design. Since these parameters in conventional parallel plate RF MEMS switch designs are in trade-off relationship, both requirements cannot be met simultaneously. In the vertical comb design, however, the actuation voltage is independent of the vertical separation distance between the contact electrodes. Therefore, the large separation gap between contact electrodes is implemented to achieve high isolation. We have designed and fabricated RF MEMS switch which has 46dB isolation at 5GHz, 0.9dB insertion loss at 5GHz and 40V actuation voltage.

• 설비공학논문집
• /
• 제16권9호
• /
• pp.828-837
• /
• 2004

The present study investigated two-phase flow distribution, phase separation and pressure drop in multi-microchannel tubes under adiabatic condition. The test section consisted of inlet and outlet headers with the inner diameter of 19.4㎜ and 15 parallel microchannel tubes. Each microchannel tube brazed to the inlet and outlet headers and had 8 rectangular ports with the hydraulic diameter of 1.32㎜. The key experimental parameters were orientation of header (horizontal and vertical), flow direction of refrigerant into the inlet header (in-line, parallel and cross flow) and inlet quality (0.1, 0.2 and 0.3). It was found that the orientation of the header had relatively large effect on the flow distribution and phase separation, while the inlet quality didn't affect much on them. The horizontal header showed the better flow distribution and phase separation characteristics than the vertical one. The parallel flow condition with the horizontal header showed the best performance for the flow distribution and phase separation characteristics under the test conditions. Two-phase pressure drops through the microchannel tubes with the horizontal header were higher than those of the microchennel tubes with the vertical header due to gravitational effect.

• Structural Engineering and Mechanics
• /
• 제15권3호
• /
• pp.331-344
• /
• 2003

The plane contact problem for two infinite elastic layers whose elastic constants and heights are different is considered. The layers lying on a Winkler foundation are acted upon by symmetrical distributed loads whose lengths are 2a applied to the upper layer and uniform vertical body forces due to the effect of gravity in the layers. It is assumed that the contact between two elastic layers is frictionless and that only compressive normal tractions can be transmitted through the interface. The contact along the interface will be continuous if the value of the load factor, ${\lambda}$, is less than a critical value. However, interface separation takes place if it exceeds this critical value. First, the problem of continuous contact is solved and the value of the critical load factor, ${\lambda}_{cr}$, is determined. Then, the discontinuous contact problem is formulated in terms of a singular integral equation. Numerical solutions for contact stress distribution, the size of the separation areas, critical load factor and separation distance, and vertical displacement in the separation zone are given for various dimensionless quantities and distributed loads.

• Current Optics and Photonics
• /
• 제8권1호
• /
• pp.30-37
• /
• 2024

Implemented at the Geochang Observatory in South Korea, our slope detection and ranging (SLO-DAR) system features a 508 mm Cassegrain telescope (f /7.8), incorporating two Shack-Hartmann wave-front sensors (WFS) for precise measurements of atmospheric phase distortions, particularly from nearby binary or double stars, utilizing an 8 × 8 grid of sampling points. With an ability to reconstruct eight-layer vertical atmospheric profiles, the system quantifies the refractive index structure function (C_n²) through the crossed-beam method. Adaptable in vertical profiling altitude, ranging from a few hundred meters to several kilometers, contingent on the separation angle of binary stars, the system operates in both wide (2.5 to 12.5 arcminute separation angle) and narrow modes (11 to 15 arcsecond separation angle), covering altitudes from 122.3 to 611.5 meters and 6.1 to 8.3 kilometers, respectively. Initial measurements at the Geochang Observatory indicated C_n² values up to 181.7 meters with a Fried parameter (r₀) of 8.4 centimeters in wide mode and up to 7.8 kilometers with an r₀ of 8.0 centimeters in narrow mode, suggesting similar seeing conditions to the Bohyun Observatory and aligning with a comparable 2014-2015 seeing profiling campaign in South Korea.