• The Journal of Asian Finance, Economics and Business
• /
• 제5권3호
• /
• pp.43-50
• /
• 2018

The paper aims to investigate the impact of trade cost on export: A Case Study Vietnam. The study conducts a static linear panel data analysis on annual data covering bilateral export between Vietnam and 70 major importers of Vietnam from 2001 to 2013. The gravity model has been one of the most successful applications in empirical trade. In this paper we apply the gravity model to estimate the impact of trade cost on Vietnamese bilateral export value. The paper uses gravity model to estimate the impact of trade cost on Vietnamese bilateral export value. The empirical results derive from a static linear panel data analysis (fixed effects model) indicates that trade cost plays a crucial role in determining the export value that occurs between Vietnam and trading partners. Besides, population of importing country, trade openness of importing country, gross domestic product of importing country and gross domestic product of Vietnam are also significant determinants of Vietnamese bilateral export value. The main findings indicates that trade cost plays a very important role in the Vietnamese bilateral export performance. This suggests that the Vietnamese government should attempt to improve domestic trade costs to enhance competitiveness and increase export growth sustainably.

• 한국측량학회:학술대회논문집
• /
• 한국측량학회 2010년 춘계학술발표회 논문집
• /
• pp.165-168
• /
• 2010

This paper describes the results of complete Bouguer anomalies computed from the Free-air anomalies that derived from Sandwell and DNSC08 mairne gravity models. Complete bouguer corrections consist of three parts: the bouguer correction (Bullard A), the curvature correction (Bullard B) and the terrain correction (Bullard C). These all corrections have been computed over the East Sea on a $1'{\times}1'$ elevation data (topography and bathymetry) derived from ETOPO1 global relief model. In addition, a constant topographic (sea-water) density of $2,670kg/m^3$ ($1,030kg/m^3$) has been used for all correction terms. The distribution of complete bouguer anomalies computed from DNSC08 are -34.390 ~ 267.925 mGal, and those from Sandwell are -32.446 ~ 266.967 mGal in East Sea. The mean and RMSE value of the difference between DNSC08 and Sandwell is $0.036{\pm}2.373$ mGal. The highest value of complete bouguer anomaly are found around the region of $42{\sim}43^{\circ}N$ and $137{\sim}139^{\circ}E$ (has the lowest bathymetry) in both models. Theses values show that the gravity distribution of both models, DNSC08 and Sandwell, are very similar. They indicate that satellite-based marine gravity model can be effectively used to analyze the geophysical, geological and geodetic characteristics in East Sea.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
• /
• pp.589-592
• /
• 2005

Gravity characteristics and Moho undulations are investigated in the Korean peninsula by using satellite gravity data. According to the development of satellite geodesy, gravity potential models which have high accuracy and resolution were released. Using the EIGEN-CGOIC model based on low orbit satellite data such as CHAMP and GRACE, geoid and gravity anomaly were calculated by spherical harmonic analysis. The study area is located at $123^{\circ}\sim132^{\circ}E, 33^{\circ}\sim43^{\circ}$N including Korea. Free-air anomalies, which show the effect of terrain, have the values between $-37\sim724 mgal. After Bouguer correction, the range of simple Bouguer anomalies is $-221\sim246$ mgal. Complete Bouguer anomalies after terrain correction increase from continent to marine. This phenomenon is related rise of Moho discontinuity. The cut-frequency for extraction of Moho undulation was determined by power spectrum analysis, and then 3D inversion modeling was implemented. The mean, maximum, minimum, and standard deviation of Moho depth undulation are -26, -36, -8, and 4.9 krn, respectively.

• 한국농공학회지
• /
• 제38권4호
• /
• pp.125-136
• /
• 1996

In order to investigate the characteristics of gravity drainage for geotextile, small-scale model tests for the geotextile chimney drain of earth dam which is a typical type of gravity drainage were carried out using 15 kinds of nonwoven and composite geotextiles. According to the results of this study, the drainage discharge of geotexgile drain generally increases with exponential function as hydraulic head increases and the increasing rate is greater in the coarser soil of dam material. It has a trend to increase when the construction slope of geotextile drain is steeper and the number of layers of geotextile is more. The relationship between the transmissivity of geotextile and the drainage discharge has positive correlation and the rate of increase is greater in the coarser soil. The geotextile products must be carefully selected in consideration of transmissivity of geotextile when the soil to be drained is coarser and the seepage flow is relatively high. Most of staple fiber nonwoven geotextile used in this study are found to be appropriate for drainage purpose. Among them, the composite geotextile the type of which geotextile is evaluated to be the most excellent material. But the geotextile of low permeability such as filament thermal bonded and filament spunbonded nowovens closely examined their transmissivity especially to be used for drainage function.

• Journal of Astronomy and Space Sciences
• /
• 제27권2호
• /
• pp.97-106
• /
• 2010

To prepare for a Korean lunar orbiter mission, a precise lunar orbit propagator; Yonsei precise lunar orbit propagator (YSPLOP) is developed. In the propagator, accelerations due to the Moon's non-spherical gravity, the point masses of the Earth, Moon, Sun, Mars, Jupiter and also, solar radiation pressures can be included. The developed propagator's performance is validated and propagation errors between YSPOLP and STK/Astrogator are found to have about maximum 4-m, in along-track direction during 30 days (Earth's time) of propagation. Also, it is found that the lifetime of a lunar polar orbiter is strongly affected by the different degrees and orders of the lunar gravity model, by a third body's gravitational attractions (especially the Earth), and by the different orbital inclinations. The reliable lifetime of circular lunar polar orbiter at about 100 km altitude is estimated to have about 160 days (Earth's time). However, to estimate the reasonable lifetime of circular lunar polar orbiter at about 100 km altitude, it is strongly recommended to consider at least $50\;{\times}\;50$ degrees and orders of the lunar gravity field. The results provided in this paper are expected to make further progress in the design fields of Korea's lunar orbiter missions.

• 한국멀티미디어학회논문지
• /
• 제13권2호
• /
• pp.225-236
• /
• 2010

본 논문은 카메라 영상 정보와 기울기 센서 정보를 통합한 바이모달 응급상황 인식방법을 제안한다. 제안된 방법은 어느 한 센서가 오작동 하거나 사용자가 착용형 기울기 센서를 착용하지 않거나, 영상 획득의 어려움이 있는 욕실과 같은 곳에 있는 경우에도 응급 상황을 감지하여 센서 간에 상호 협력과 보완을 함으로써 응급 상황을 인식할 수 있다. 본 논문에서는 HMM 학습 및 인식을 통해 걷는 동작, 바닥에 앉는 동작, 소파에 앉는 동작, 눕는 동작, 기절 동작을 판단할 수 있도록 하였다. 영상의 특징 벡터와 기울기 센서의 특징 벡터를 결합하여 학습하고 인식했을 때, 인식률의 향상을 가져올 수 있었다. 또한 다양한 조명의 변화에도 적응적 배경 모델을 통해 움직이는 객체를 강건하게 검출할 수 있어서 높은 인식률을 유지할 수 있었다.

• 한국지구물리탐사학회:학술대회논문집
• /
• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
• /
• pp.379-382
• /
• 2003

In gravity data correction process, mass effect of the upper part of base level is removed with Bouguer density. Usually, Bouguer density is estimated as a mean density in the field area. But, this may causes a serious problem when ore body is in the area. To overcome this problem, we tried to apply a new method mixing up mass corrections and inversion (3DGTI). 3-D Gravity Terrain Inversion (3DGTI) includes information of topography and distribution of Bouguer density. For this method does not remove the mass effect above base level, it is no longer useless to use Bouguer density. Numerical model tests have shown that the 3DGIT successfully retrieves the anomalous subsurface density distribution of both surface and deeper layers. Model tests shows that this method shows better results than those of conventional one, especially when main target is ore body. The inversion result well delineates the three-dimensional shape of the intruded granite body and basement.

• 한국정밀공학회지
• /
• 제28권8호
• /
• pp.959-965
• /
• 2011

This paper presents the dynamic modeling and vibration suppression methods for axially deploying beams subjected to gravity. A modal modeling method is employed to develop the lateral vibration model for axially deploying beams. Simulation is made to validate the proposed model as well as to investigate the dynamics of axially deploying beams. This paper rigorously investigates the gravity effect as a source of vibration for axially deploying beams. In order to suppress lateral vibration for deploying beams, the moving speed command is modified by using the input shaping method, Experiments are also performed to prove the proposed vibration suppression method. The simulations and experiments show that the proposed modeling and input shaping methods are effective for the dynamic analysis and vibration suppression of axially deploying beams subjected to gravity.

• 한국측량학회지
• /
• 제24권2호
• /
• pp.183-191
• /
• 2006

최대 차수 10800의 초 고차 구 조화함수를 전개하여 중력을 모델링 하고, 이를 이용하여 상향 연속의 정확도를 검증하였다. 초 고차 구조화 함수에 의한 중력 모델링에 있어 수치계산적 난점인 르장드르 함수의 언더플로와 오버플로를 128 비트 연산에 의하여 성공적으로 수행하였으며, 이를 이용하여 지오이드상의 중력이상값을 공간 상도 $1'{\times}1'$ 으로 계산하였다. 생성된 중력이상값에 다양한 크기의 잡음을 첨가하고 자료의 간격을 달리하여 상향연속을 수행하였으며, 이로부터 도출된 중력 섭동 벡터와 중력 모델로부터 직접 계산된 섭동 벡터와의 비교를 통하여 실제적인 상향연속의 정확도를 할당하였다. 상향연속 방법의 비교에 있어, 직접방법이 포아송 방법에 비해 월등히 좋은 정확도를 보였고, 지상 중력자료의 잡음이 적을수록 또한 자료의 간격이 작을수록 상향연속에 의한 중력 섭동벡터의 정확도가 높게 나타남을 확인하였다. 특히 차세대 관성항법장치의 정밀 항법을 위한 중력의 필요조건인 5mGal의 정확도를 위해선, 지상 중력의 잡음 정도가 5mGal 이하, 자료의 간격이 2arcmin 이하이어야 함을 도출하였다.

• 대한교통학회지
• /
• 제29권2호
• /
• pp.81-89
• /
• 2011

통행분포(trip distribution)는 4단계 통행수요추정의 첫 단계인 통행발생(trip generation)에서 구해진 통행생성(trip production)과 통행 유인(trip attraction)을 연결시키는 작업이다. 즉 하나의 존에서 생성 또는 유인되는 통행량을 다른 존에 분포시키는 과정이다. 이에 반해, 통행수단선택(transport mode choice)은 통행자들이 어떤 교통수단을 선택할 것인지를 결정하는 단계이다. 그러나, 이들 통행분포단계와 통행수단선택단계는 서로 밀접한 관계가 있음에도 불구하고, 서로 독립적으로 수행되어온 경향이 있었다. 본 연구에서는 통행분포단계와 통행수단선택단계를 통합한 모형을 제시하고 이를 풀기 위한 알고리듬도 제시한다. 통합모형의 통행분포모형으로는 중력모형(gravity model)을 적용되며, 수단선택모형으로는 로짓모형(logit model)을 이용한다. 본 연구의 통합모형은 각 단계별로 개별적으로 진행되는 추정단계가 하나의 모형 틀 안에서 통합적으로 이루어져 좀 더 현실적이며, 통행비용의 불일치 문제가 해소될 수 있다. 또한, 통합모형에서도 균형조건(equilibrium condition)이 존재함을 증명하며, 통합모형의 민감도 분석을 통하여 기존 모형과의 차이점을 설명한다.