• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.35 no.5
• /
• pp.1157-1163
• /
• 2015

The purpose of this study is to reveal the effects of the number of users and their spatial distribution on the evacuation time in a road tunnel in the event of a fire. An agent-based evacuation model was implemented using Netlogo following the ODD protocol. The proposed model illustrates how the evacuation behavior of one can hinder others across different evacuation environments. Simulations show that evacuation time increases with the number of users when they are randomly located in a road tunnel.

• International Journal of Highway Engineering
• /
• v.10 no.4
• /
• pp.139-150
• /
• 2008

In this study, It is focused on development of the forecasting model about trumpet InterChange(IC) ramp accident because of the frequency of accident in ramp more than highway basic section and trend the increasing accident in ramp. The independent variables was selected through statistical analysis(correlation analysis, multi-collinearity etc) by ramp types(direct, semi-direct and loop). The independent variables and accident rate is non-linear relationship. So it made new variables by transformation of the independent variables. The forecasting models according to exit-ramp type (direct, semi-direct and loop) are built with statistical multi-variable regression using all possible regression method. And the forecasts of the models showed high accuracy statistically. It is expected that the developed models could be employed to design trumpet IC ramp more cost-efficiently and safely and to analyze the causes of traffic accidents happened on the IC ramp.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.15 no.2
• /
• pp.69-80
• /
• 2013

This study evaluates the seismic performance of road tunnels designed before the provisions for seismic design of tunnels were first established in 1999. Extensive design data and site investigation reports are investigated to select tunnels sections that are considered to be most susceptible to seismically induced damage under earthquake loading. Detailed analyses are performed on selected tunnels. The methods used are method of displacement and dynamic analysis. In performing the method of displacement, which is a type of pseudo-static analysis method used for underground structures, full domain and reduced domain modeling were used. The dynamic analyses are performed using finite difference method and using nonlinear constitutive model. Comparisons show that the reduced domain method of displacement match very closely with the dynamic analysis, demonstrating that it is the most suitable method for evaluating the seismic performance of road tunnels built in rocks. It is also shown that road tunnels, for which seismic design were not applied, are safe under the seismic risks corresponding to an earthquake with a return period 1000 years. It is concluded that additional seismic retrofit of tunnels is not necessary.

• Journal of the Korea Society of Computer and Information
• /
• v.27 no.9
• /
• pp.13-20
• /
• 2022

It's proposed and analyzed ML(Machine Learning) models to predict vehicle FC(Fuel Consumption) in real-time. The test driving was done for a car to measure vehicle speed, acceleration, road gradient and FC for training dataset. The various ML models were trained with feature data of speed, acceleration and road-gradient for target FC. There are two kind of ML models and one is regression type of linear regression and k-nearest neighbors regression and the other is classification type of k-nearest neighbors classifier, logistic regression, decision tree, random forest and gradient boosting in the study. The prediction accuracy is low in range of 0.5 ~ 0.6 for real-time FC and the classification type is more accurate than the regression ones. The prediction error for total FC has very low value of about 0.2 ~ 2.0% and regression models are more accurate than classification ones. It's for the coefficient of determination (R²) of accuracy score distributing predicted values along mean of targets as the coefficient decreases. Therefore regression models are good for total FC and classification ones are proper for real-time FC prediction.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.28 no.2D
• /
• pp.155-162
• /
• 2008

This study shows how to estimate the design hour factor when the counting stations don't have all of the hourly volumes such as in a coverage survey. A coverage survey records traffic volume from 1 to 5 times in a year so it lacks the detailed information to calculate the design hour factor. This study used the traffic volumes of permanent surveys to estimate the design hour factor in coverage surveys using correlation and regression analysis. A total 7 independent variables are used : the coefficient of variance of hourly volume, standard deviation of hourly volume, peak hour volume, AADT, heavy traffic volume proprotion, day time traffic volume proportion and D factor. All of variables are plotted on a curve, so it must use non-linear regression to analyze the data. As a result the coefficient of determination and MAE are good at logarith model using AADT.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.26 no.3
• /
• pp.263-273
• /
• 2008

The precision of sensors' position is particularly important in the application of road extraction or digital map generation. In general, the various ranging solution systems such as GPS, Total Station, and Laser Ranger have been employed for the position of the sensor. Basically, the ranging solution system has problems that the signal may be blocked or degraded by various environmental circumstances and has low temporal resolution. To overcome those limitations a IMU/range integrated system could be introduced. In this paper, after pointing out the limitation of extended Kalman filter which has been used for workhorse in navigation and geodetic community, the two sampling based nonlinear filters which are sigma point Kalman filter using nonlinear transformation and carefully chosen sigma points and particle filter using the non-gaussian assumption are implemented and compared with extended Kalman filter in a simulation test. For the ranging solution system, the GPS and Total station was selected and the three levels of IMUs(IMU400C, HG1700, LN100) are chosen for the simulation. For all ranging solution system and IMUs the sampling based nonlinear filter yield improved position result and it is more noticeable that the superiority of nonlinear filter in low temporal resolution such as 5 sec. Therefore, it is recommended to apply non-linear filter to determine the sensor's position with low degree position sensors.

• Journal of Korean Society of Transportation
• /
• v.24 no.7 s.93
• /
• pp.41-51
• /
• 2006

In this paper, a fundamental study on the characteristics of traffic accidents according to the alignment and traffic conditions on the ramp of freeway is addressed. The macro-and-micro scope analysis of characteristics about traffic accidents on the trumpet-IC ramps is conducted depending on the entering and exit ramp types under the various conditions of traffic volume and alignment And it is turned out that the conditions of alignment. such as radius, differences of curvatures, and main road grade, and traffic volume relate to the ramp accidents of trumpet IC according to ramp types, such as direction, semi-direction, and loop. Macroscopically, AR (Accident Rate) according to trumpet IC types, A and B, is analyzed nearly equal, but Number of accidents occurred in IC type B shows about 1.5 times higher than type A. And AR of exit ramps shows three times more than entrance ramps. Microscopically, ARs for each exit-ramp type, according to the increment of traffic volume, the difference of curvatures. and the first radius, exponentially decrease respectively. But relationships between AR and the second radius or exit ramp shows inverted U-shaped. AR according to main-road grade Peaks between -1.5% and -0.5%. It is expected that the developed models not only are employed to make design of trumpet-IC ramp more cost-efficiently and safely, but also contribute to making alternatives to the reduction of traffic accidents on trumpet IC ramps under the conditions of high traffic accident rate.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2006.05a
• /
• pp.1256-1260
• /
• 2006

하천 복개나 하상 도로 등 교각이 밀집된 군교각은 홍수시에 큰 수위 상승을 유발할 수 있다. 이런 군교각에 의한 배수위 효과를 분석하기 위해 다양한 경우에 대한 실험과 2차원 수치 모의를 수행하였다. 수리 실험은 수치 모형의 정확도를 검증하기 위해 수행되었으며, 다양한 종류의 교각 배치 경우에 대해서는 수치 모의를 위주로 분석하였다. 수리 모형 실험을 통하여 2차원 수치 모형인 RMA-2의 신뢰성에 대해 검토한 결과 이 모형은 교각에 의한 수위 상승 효과를 상당한 정확도로 모의할 수 있음을 알 수 있었다. 군교각에 의한 수위상승 인자를 흐름 횡단면 교각 수, 흐름 방향의 교각 간격, 흐름방향의 교각 수로 선정하여 이들 변수들을 조합하여 다양한 경우에 대하여 수리 실험과 수치 모의를 병행하였다. 단일 횡단면의 교각 수 증가에 따른 배수위 상승은 횡단면의 차단율 증가에 따라 선형적으로 증가한다. 그러다가 차단율이 어느 정도 이상에 이르면 수위 상승이 매우 급격히 증가하는 경향을 보인다. 또한 흐름방향 교각 수 증가에 따라 배수위는 선형적으로 증가함을 알 수 있는데, 이는 교각에 의한 상호 간섭 및 중첩에 의한 것으로 생각된다. 흐름방향 교각 간격을 증가시켜도 배수위 상승이 크게 증가하였으나, 교각의 지름의 약 9배 (9D) 이상 떨어진 다음부터는 배수위 상승량이 감소하는 것을 알 수 있다. 이런 점에서 볼 때, 군교각은 교각 지름의 9배 정도 떨어진 경우 배수위 상승 효과가 중첩되지 않음을 알 수 있었다.

• The KIPS Transactions:PartB
• /
• v.11B no.7 s.96
• /
• pp.885-892
• /
• 2004

In this paper, we propose a multi-modal biometrics system based on face and signature recognition system. Here, the face recognition system is designed by fuzzy LDA, and the signature recognition system is implemented with the LDA and segment matching methods. To effectively aggregate two systems, we obtain statistical distribution models based on matching values for genuine and impostor, respectively. And then, the final verification is Performed by the support vector machine. From the various experiments, we find that the proposed method shows high recognition rates comparing with the conventional methods.

• The Journal of the Acoustical Society of Korea
• /
• v.13 no.5
• /
• pp.15-23
• /
• 1994

We developed an electronic lens for acoustic imaging systems, which is linear array with 31 microphones equally spaced with distance 34mm. Resonant frequency fo receiver circuit coupled to microphone is 20 kHz. We arranged 16 microphones horizontally and 15 microphones vertically, so that the array allows us to obtain a 2 dimensional angle of source, and to track the motion of source in real time. Due to the problem of aliasing in discrete Fourier Transfrom, the maximum observable angle of the lens is limited to 15${\circ}$. We also employed quadrature phase detection scheme to adjust the focus. We have tested the acoustic lens with a personal computer in an anechoic room and obtained the results agreed with the acoustic imaging theory.