• International Journal of Highway Engineering
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• v.10 no.3
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• pp.79-86
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• 2008

This paper proposed the appropriate installation angle of skewed sensors for measuring vehicle wandering data, which are collected to figure out the location of dynamic weight of a moving vehicle on roadways. We developed a device using tape-switch sensors and a computer program and collected vehicle wandering data with the device and probe vehicles. As a result, the steeper the skewed sensor was installed, the lower the error was shown. However, we could not collect proper data when a skewed sensor was set up higher than $30^{\circ}$ due to tandem axle. Therefore, this study suggested the appropriate angle of skewed sensors as a degree of $20^{\circ}$ to $25^{\circ}$ for gathering wandering data.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.1
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• pp.177-184
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• 2023

In this paper, based on Arduino, a vehicle is installed at the bottom of the 3D printer so that Arduino controls the vehicle that can expand the moving space. A stepping motor was mounted on the front wheel of the vehicle and precisely controlled using a motor driver. As a result, when moving 5cm, 25cm, and 50cm, the mean value of error rate was 0.6%, 0.04%, and 0.02%, respectively, to enable accurate distance control.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.3
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• pp.625-637
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• 2015

This study aims to calculate optimal travel speeds based on analysis of the AVI data collected in the uninterrupted traffic flow, and the results are as follows. Firstly, we looked into the distribution of the sectional travel times of each probe vehicle and compared the difference in the sectional travel speeds of each probe vehicle. As a result, it is shown that outliers should be removed for the distribution of the sectional travel times. Secondly, there were differences among type 1(passenger automobiles) & type 2(automobiles for passengers and freight) and type 4(special automobiles) in the non-congestion section. thus it was revealed that there is a necessity to remove type 4(special automobiles) when calculating the sectional travel speeds. Thirdly, Based on the results of these, the optimal outlier removal procedures were applied to this study. As a result, it showed that the MAPE was between 0.3% and 2.0% and RMSE was between 0.3 and 2.3 which are very similar figures to the actual average traffic speed. Also, the minimum sample size was satisfied at the confidence level of 95%. The result of study is expected to serve as a useful basis for the local government to build the AVI. In the future, it will be necessary to study to integrate AVI data and other data for more accurate traffic information.

• Journal of Space Technology and Applications
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• v.1 no.3
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• pp.302-318
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• 2021

A basic study was conducted on how to determine the launch timing of a space probe targeting an Earth-approaching asteroid. In the future, when a probe mission targeting an asteroid approaching Earth's orbit is conducted in Korea, in order to determine the launch time, an appropriate solution should be obtained by applying the Global Optimization technique. For this, accurate current orbit information of each asteroid must be obtained first, and prior scenarios such as Earth's orbit information, main engine performance information of the probe and launch vehicle, the number of gravity-assisted maneuvers, and maximum flight time limit should be discussed. Also, the criteria for optimization should be determined first. In this paper, based on these prerequisites and information, a method for finding the launch time of an asteroid probe was studied using the open source software such as PyKEP and Evolutionary Mission Trajectory Generator (EMTG) which are the programs for interplanetary trajectory generation purpose.

• Journal of Astronomy and Space Sciences
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• v.39 no.3
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• pp.117-126
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• 2022

The Ionospheric Anomaly Monitoring by Magnetometer And Plasma-probe (IAMMAP) is one of the scientific instruments for the Compact Advanced Satellite 500-3 (CAS 500-3) which is planned to be launched by Korean Space Launch Vehicle in 2024. The main scientific objective of IAMMAP is to understand the complicated correlation between the equatorial electro-jet (EEJ) and the equatorial ionization anomaly (EIA) which play important roles in the dynamics of the ionospheric plasma in the dayside equator region. IAMMAP consists of an impedance probe (IP) for precise plasma measurement and magnetometers for EEJ current estimation. The designated sun-synchronous orbit along the quasi-meridional plane makes the instrument suitable for studying the EIA and EEJ. The newly-devised IP is expected to obtain the electron density of the ionosphere with unprecedented precision by measuring the upper-hybrid frequency (f_UHR) of the ionospheric plasma, which is not affected by the satellite geometry, the spacecraft potential, or contamination unlike conventional Langmuir probes. A set of temperature-tolerant precision fluxgate magnetometers, called Adaptive In-phase MAGnetometer, is employed also for studying the complicated current system in the ionosphere and magnetosphere, which is particularly related with the EEJ caused by the potential difference along the zonal direction.

• Proceedings of the KIPE Conference
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• 2010.11a
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• pp.215-217
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• 2010

This paper describes the test results of radiated compatibility with Ariane 5 launcher performed on the COMS Satellite test facility. Firstly, the Radiated Emission test results are analyzed in compliance with the Radiated Susceptibility requirement specification of Ariane 5 launcher. The satellite nominal operation is monitored during injection a radiated electric field corresponding to the launcher emissions levels in critical frequency ranges. And also, E-field are measured through a probe located at external units level in order to assess the EMC safety margin in Radiated mode.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.1595-1597
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• 2011

과거에는 고속도로 상에 일정간격으로 설치하여 운영 중인 VDS(Vehicle Detection System)에서 주기적으로 검지되는 지점자료나 실제로 도로를 주행하면서 교통상황을 측정하는 프로브 차량(Probe Vehicle)들을 이용하여 통행시간을 추정해 왔으나 단순한 현시점에서의 통행시간을 나타내는 점이나 설치구간이 조밀하지 못한 곳에서의 정확성 등 많은 문제점이 있어왔다. 이에 본 연구에서는 고속도로 통행료 수납자료(Toll Collection System)를 출발시각 기준으로 정렬하고, 이를 Fuzzy c-means 클러스터링 기법을 사용하여 고속도로 통행료 수납자료의 특성에 따라 분류한 후 하나의 대푯값으로 추출하여 Kalman Filter 기법에 적용하는 고속도로 통행시간 예측 모형을 설계한다.

• Journal of Korean Society of Transportation
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• v.27 no.5
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• pp.63-74
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• 2009

One of the effective countermeasures for preventing traffic accidents is to provide traffic safety warning information to drivers. Provision of warning information would lead to safer driving to avoid accident occurrence. This study investigated the effects of in-vehicle warning information on driver's behavior. A variety of warning information contents using text, sound, and pictograms were prepared for the field experiments. Individual vehicle speed and acceleration data, which represent quantitative drivers' behavior in response to in-vehicle warning information, were collected using differential global positioning systems (DGPS). Statistical analyses including ANOVA and Tukey's pairwise comparison were conducted. It is expected that the results could be invaluable for designing more effective warning information.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.149-153
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• 2012

We propose a traffic information service for which traffic data are collected over ad-hoc networks from neighbor vehicles, processed to minimize the data size, and eventually provided to its destination. The proposed scheme simply relies on the existing navigtion systems in vehicles and wireless communication devices for vehicle-to-vehicle communication, rather than on a separately established server. It allows collecting and analyzing traffic status of large areas without incorporating separated monitoring systems, e.g., probe cars and enables to provide accurate traffic information to drivers in timely manner. We also evaluate its performance by ns-3 simulation.

• Wind and Structures
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• v.28 no.4
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• pp.203-213
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• 2019

The topography and geomorphology are complex and changeable in western China, so the railway transition section is common. To investigate the aerodynamic effect of the subgrade-tunnel transition section, including a cutting-tunnel transition section, an embankment-tunnel transition section and two typical scenarios for rail infrastructures, is selected as research objects. In this paper, models of standard cutting, embankment and CRH2 high-speed train with the scale of 1:20 were established in wind tunnel tests. The wind speed profiles above the railway and the aerodynamic forces of the vehicles at different positions along the railway were measured by using Cobra probe and dynamometric balance respectively. The test results show: The influence range of cutting-tunnel transition section is larger than that of the embankment-tunnel transition section, and the maximum impact height exceeds 320mm (corresponding to 6.4m in full scale). The wind speed profile at the railway junction is greatly affected by the tunnel. Under the condition of the double track, the side force coefficient on the leeward side is negative. For embankment-tunnel transition section, the lift force coefficient of the vehicle is positive which is unsafe for operation when the vehicle is at the railway line junction.