• 한국지하수토양환경학회지:지하수토양환경
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• 제8권3호
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• pp.13-22
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• 2003

현장공기분사공정의 복원효율에 있어서 중요한 인자로 작용 할 수 있는 것은 공기가 지하 포화대수층을 통과하면서 생기는 공기분사에 따른 흐름 양상과 토양입자크기에 따른 공기의 영향반경이다. 토양입자크기별 AMG 0.34, 1.38, 3.89 mm diameter 3가지 입자크기로 실험한 결과 AMG 0.34 mm diameter의 포화 대수층에서는 공기가 처음 결정된 방향으로만 흐르는 채널링 현상(channelized air flow)과 포화 대수층 가장 윗면에서는 확장모양(expansion state)을 가졌으며, 공기영향반경은 단위 면적당 15.2%/$\textrm{m}^2$이었다. AMG 1.38, 3.89 mm diameter의 포화 대수층에서는 공기가 퍼지는 현상(pervasive air flow)과 포화 대수층 가장 윗면에서는 각각 붕괴의 조짐(onset of collapse), 안정한 상태로 퍼짐모양(approach to steady state)을 가졌으며, 단위면적당 각각 37.0%/$\textrm{m}^2$, 30.0%/$\textrm{m}^2$영향반경이 계산되었다. 이 실험을 통해서 현장공기분사공정에 있어서 토양입자 크기에 따른 최대 영향반경효율을 얻을 수 있는 토양입자의 크기는 AMG 1.5-2.5 mm diameter로 사료된다.

• Asian Journal of Innovation and Policy
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• 제10권2호
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• pp.195-211
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• 2021

This paper measures the economic impacts of the U.S. port investment strategies coping with the Panama Canal expansion. Using secondary import data, negative and positive estimates of the impacts were presented in this study. Reduced port activities into the West Coast Customs Districts negatively affect transportation and warehousing industries, among other effects. Still, they have simultaneous positive effects in other states from increased imports resulting from modal shifts and changes in the entry port located in the South and East coasts. This study applied the supply-driven National Interstate Economic Model that measures all interstate trade among the U.S. states to divert foreign imports from 15 Pacific Rim countries. For this purpose, the following assumption was adopted: larger ships using the canal will lead to a redirection of seaborne trade among U.S. (and other) ports and result in secondary effects, e.g., using different freight modes and regional growth spillovers. This study also accounted for the entry point change and significant port investments for foreign trade under alternative scenarios. The choice of ports for international trade depends on decisions about how to minimize multimodal delivery costs. The total direct reduction of transportation and warehousing activities associated with foreign imports in the West Coast ports was estimated at $3.3 billion, leading to total negative effects of $5.8 billion. Total positive impacts from the shift of transportation modes with the choice of an entry port and new warehousing activities for foreign imports in the selected 12 states varied. As expected, states that involved an entry port had the most prominent benefits, but Texas, New York, and New Jersey may be benefited through all the port enhancement projects in the U.S. Also, except for Transportation and Postal, and Warehousing industries, Construction is another dominant positive affected industry of the Canal expansion in the U.S.

• 대한토목학회논문집
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• 제35권6호
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• pp.1329-1338
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• 2015

본 연구에서는 서울시 지하철 분담률의 지역적 차이에 대한 원인분석을 통하여 올바른 정책적 수단을 찾기 위한 모형을 개발하고자 한다. 이를 통해 가장 영향력 있는 두 개의 변수를 찾아내어 Portfolio 분석을 실시하였다. 분석결과, 첫째, 지하철 분담률에 영향을 미치는 요인은 크게 역세권 요인과 마을버스 요인으로 나타났다. 이는 줄어들고 있는 지하철 분담률을 개선하기 위해서 역세권지역의 확장, 역사수 증설, 마을버스 노선수의 증대가 요구됨을 의미한다. 둘째, Portfolio 분석결과 지하철 연계 강화를 위한 개선유형은 역세권 중심 개선과 마을버스 중심 개선지역으로 구분되었다. 역세권 중심 개선지역은 강북구, 서대문구, 금천구, 관악구로 나타났고, 송파구와 중구는 마을버스 중심 개선지역으로 나타났다. 따라서 향후 지하철 분담률 향상을 위해서는 두 가지 측면의 주요 요인을 유형별(지역)로 적절히 고려하는 대중교통 관련 정책을 제시하는 것이 필요할 것으로 판단된다.

• Ocean Systems Engineering
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• 제1권4호
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• pp.337-353
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• 2011

In the present study, an offshore platform having large partial porous cylindrical members, which are composed of permeable and impermeable cylinders, is suggested. In order to calculate the wave force on large partial porous cylindrical members, the fluid domain is divided into three regions: a single exterior region, N inner regions and N beneath regions, and the scattering wave in each fluid region is expressed by an Eigen-function expansion method. Applying Darcy's law to the porous boundary condition, the effect of porosity is simplified. Wave excitation forces and wave run up on the structures are presented for various wave conditions. For the idealized three-dimensional platform having large partial porous cylindrical members, the dynamic response evaluations of the platform due to wave forces are carried out through the modal analysis. In order to examine the effects of soil-structure interaction, the substructure method is also applied. The displacement and bending stress at the selective nodal points of the structure are computed using various input parameters, such as the shear-wave velocity of soil, the wave height and the wave period. Applying the Monte Carlo Simulation (MCS) method, the reliability evaluations at critical structure members, which contained uncertainties caused by dynamic forces and structural properties, are examined by the reliability index with the results obtained from MCS.

• Journal of Mechanical Science and Technology
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• 제20권9호
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• pp.1323-1338
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• 2006

An analytical method to estimate the coupled frequencies of the circular plate submerged in fluid is developed using the finite Fourier-Bessel series expansion and Rayleigh-Ritz method. To verify the validity of the analytical method developed, finite element method is used and the frequency comparisons between them are found to be in good agreement. For the perforated plate submerged in fluid, it is almost impossible to develop a finite element model due to the necessity of the fine meshing of the plate and the fluid at the same time. This necessitates the use of solid plate with equivalent material properties. Unfortunately the effective elastic constants suggested by the ASME code are found to be not valid for the modal analysis. Therefore in this study the equivalent material properties of perforated plate are suggested by performing several finite element analyses with respect to the ligament efficiencies.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1764-1768
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• 2004

In the near future, robots will be used for the personal use. To provide useful services to humans, it will be necessary for robots to understand human intentions. Consequently, the development of emotional interfaces for robots is an important expansion of human-robot interactions. We designed and developed an intelligent emotional interface for the robot, and applied the interfaces to our humanoid robot, AMIET. Subsequent human-robot interaction demonstrated that our intelligent emotional interface is very intuitive and friendly

• 한국항만경제학회지
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• 제20권1호
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• pp.21-42
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• 2004

This paper addresses the operation, problems, and development policy of Gwangyang Port, Korea. This paper aims to analyze the operation condition and problems of Gwangyang Port and suggest long-term policies for developing Gwangyang Port as a logistic hub in northeast period. It is made up of three main sections: the operation, problems, and forecast of freight volumes; analysis of operational results of Gwangyang Port; development strategies of Gwangyang Port as a Logistics Hub. This paper was mainly based on a review of current papers/reports, an analysis of secondary data, and questionnaire survey. The major development strategies identified consisted of expansion regular service sea-route, formation of inter-modal transportation system, strengthening of port sales for Gwangyang port's recognition, securing operation-profits by fixed cargo volume, and promotion of free tread zone.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.405-412
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• 2004

This study measures the investment effects of railroad industries on Korean economics, using the table of industry relation analysis. Until now, few studies have analyzed the economic effects of railroad in Korea so that this study can have a big implication for transportation policies in making decisions on its investment level as top priority. This study finds that railroad investment effects are larger than those of road on the national economics and, thus, impling that the expansion of railroad investment is required to grow continuously national economics as well as a major modal of transportation networks.

• 대한기계학회논문집
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• 제2권3호
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• pp.62-68
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• 1978

The influences of the large amplitude free vibrations of simply supported Timoshenko beams with ends restrained to remain a fixed distance apart and with no axial restraints, which cause a longitudinal elastic force and a longitudinal inertia force, respectively, are investigated. The equations of motion derived by an appropriate linearizarion of the nonlinear strain- displacement relation have nonlinear terms arising from large curvature, longitudinal elastic force and longitudinal inertia force. The fourth order nonlinear partial differential equations for the deflection, can be reduced to the nonlinear ordinary differential equations by means of Galerkin procedure and a modal expansion. The general response and frequensy-amplitude relations are derived by the perturbation method of strained parameters. Comparison with previously published results is made.

• 전자공학회논문지D
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• 제35D권2호
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• pp.70-77
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• 1998

An aerial image simulator for the synchroton X-ray proximity lithography system has been developed. The modal expansion method and Rayleigh-Sommerfeld diffraction theory are used in calculating the aerial image which is formed by diffracting of the partially coherent X-ray, Experimental results of PALC(POSTECH Advanced Lithography Center) lighography system and simulated results are compared. The experimental and theoretical values of the width of replicated lines are consisted with the relative error less than ~5%. The method to determine the divergent angle of X-ray from the analysis of the width of replicated lines is given.