• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2007년도 추계학술대회 논문집
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• pp.333-334
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• 2007

• 천문학회보
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• 제40권1호
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• pp.63.1-63.1
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• 2015

In this study, we determine coronal electron density distributions by analyzing DH type II radio observations based on the assumption: a DH type II radio burst is generated by the shock formed at a CME leading edge. For this, we consider 11 Wind/WAVES DH type II radio bursts (from 2000 to 2003 and from 2010 to 2012) associated with SOHO/LASCO limb CMEs using the following criteria: (1) the fundamental and second harmonic emission lanes are well identified; (2) its associated CME is clearly identified in the LASCO-C2 or C3 field of view at the time of type II observation. For these events, we determine the lowest frequencies of their fundamental emission lanes and the heights of their leading edges. Coronal electron density distributions are obtained by minimizing the root mean square error between the observed heights of CME leading edges and the heights of DH type II radio bursts from assumed electron density distributions. We find that the estimated coronal electron density distribution ranges from 2.5 to 10.2-fold Saito's coronal electron density models.

• 대한교통학회지
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• 제5권2호
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• pp.19-35
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• 1987

Transportation energy saving is a national concern because all national petroleum energy is imported. A number of intersections are operating as semi-protected intersections, which have left-turn signal but not exclusive left-turn lanes, because of limited roadways in urban areas. Since the traffic signal methods for the intersections having left-turn signal/lanes cannot be applied to the semi-protected intersection, it is needed to develop a new technique. The purpose of this study was to develop a traffic signal timing method at semi-protected intersections for energy saving and to computerize the method for the practical use. A probability model which could estimate left-turn utilization factors of through traffic during green signal was developed based on field studies. Employing the factors, macro-models to estimate vehicular average delay and proportions of vehicles stopped at the semiprotected intersections were developed. The calculated values of the delay model agreed well with the simulated values of a simulation model using SLAM Ⅱ, a simulation language. Using the two models and the idling fuel consumption rate and the excess fuel consumption per stop-go speed change of vehicles. a traffic signal timing method at semi-protected intersections for energy saving was developed and computerized. The method can be used for other measures of effectiveness such as minimum delay, minimum stop ratio, etc.

• 대한토목학회논문집
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• 제31권6D호
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• pp.765-769
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• 2011

기존의 이동식 기준장비는 갓길의 폭이 1.5m 이하인 도로 구간에는 설치가 어려우며 장비가 크고 무거워서 차량과의 충돌 시 피해가 클 수 있으며 한 번에 다차로 검지가 불가능하다. 본 연구에서는 이러한 문제점을 노정하고 있는 기존의 이동식 기준장비의 단점을 극복하기 위하여 연구 개발된 USN-기반 이동식 기준장비의 특징을 기술하고 그 성능수준을 현장 적용을 통하여 평가하였다. 그 결과 본 연구에서 개발된 장비는 기존의 이동식 기준장비가 가지고 있는 운영상의 단점을 극복할 뿐 아니라 기준장비가 가져야 할 성능수준을 만족하는 것으로 나타났다.

• 정보처리학회논문지A
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• 제14A권7호
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• pp.391-398
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• 2007

본 논문에서는 차세대 모바일 단말 카메라 표준 인터페이스인 MIPI CSI-2 및 D-PHY를 설계하였다. 제안된 CSI-2는 레인별로 존재하는 버퍼를 하나로 통합하여 송수신단이 지원하는 레인의 개수가 다른 경우에도 유연하게 관리 될 수 있는 멀티레인관리계층을 가진다. 설계된 CSI-2 및 D-PHY는 테스트 벤치를 통해 RTL 검증되었다. 또한 FPGA로 합성된 후 테스트 베드를 통해 기능 검증이 이루어 졌으며, 실제 단말기에 적용하여 동작 여부를 확인 하였다. 설계된 CSI-2 및 D-PHY 모듈은 브리지 형태로 제공되어 기존의 카메라 센서와 호스트 프로세서와 오프 칩 형태로 사용할 수 있을 뿐 아니라, 차세대 모바일 카메라 컨트롤러와 온 칩 화 가능한 IP 형태로도 사용 가능하다.

• 한국자동차공학회논문집
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• 제20권4호
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• pp.16-24
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• 2012

This paper proposes a method utilizing Differential Global Position System (DGPS) with Real-Time Kinematic (RTK) and pre-built Geo-graphic Information System (GIS) to detect lane departure of a vehicle. The position of a vehicle measured by DGPS with RTK has 18 cm-level accuracy. The preconditioned GIS data giving accurate position information of the traffic lanes is used to set up coordinate system and to enable fast calculation of the relative position of the vehicle within the traffic lanes. This relative position can be used for safe driving by preventing the vehicle from departing lane carelessly. The proposed system can be a key component in functions such as vehicle guidance, driver alert and assistance, and the smart highway that eventually enables autonomous driving supporting system. Experimental results show the ability of the system to meet the accuracy and robustness to detect lane departure of a vehicle at high speed.

• International Journal of Automotive Technology
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• 제7권5호
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• pp.609-618
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• 2006

This paper presents the lateral control of an autonomous vehicle by using a look-ahead sensing system. In look-ahead sensing by an absolute positioning system, a reference lane, constructed by straight lanes or circular lanes, was switched by a segment switching algorithm. To cope with sensor noise and modeling uncertainty, a robust LMI-based $H_{\infty}$ lateral controller was designed by the feedback of lateral offset and yaw angle error at the vehicle look-ahead. In order to verify the safety and the performance of lateral control, a scaled-down vehicle was developed and the location of the vehicle was detected by using an ultrasonic local positioning system. In the mechatronic scaled-down vehicle, the lateral model and parameters are verified and estimated by a J-turn test. For the lane change and reference lane tracking, the lateral controllers are used experimentally. The experimental results show that the $H_{\infty}$ controller is robust and has better performance compared with look-down sensing.

• 한국도로학회논문집
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• 제20권2호
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• pp.67-74
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• 2018

PURPOSES : The goal of this study is the development of roundabout accident models for urban and non-urban areas. METHODS : This study performed a comparative analysis of the regional factors affecting accidents. Traffic accident data were collected for the period 2010~2014 from the TAAS data set of the Road Traffic Authority. To develop the roundabout accident models, the Poisson and negative binomial regression models were used. A total of 25 explanatory variables such as geometry, and traffic volume were used. RESULTS : The key findings are as follows: First, it was found that the null hypotheses that the number of accidents is the same should be rejected. Second, three Poisson regression accident models, which are statistically significant (${\rho}^2$ of 0.154 and 0.385) were developed. Third, it was noted that although the common variable of the three models (models I~III) is the number of entry lanes, the specific variables are entry lane width, roundabout sign, number of circulatory roadways, splitter island, number of exit lanes, exit lane width, number of approach roads, and truck apron. CONCLUSIONS : The results of this study can provide suggestive countermeasures for decreasing the number of roundabout accidents.

• 한국도로학회논문집
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• 제20권2호
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• pp.119-126
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• 2018

PURPOSES : The purpose of this study is to develop a crash prediction model at signalized intersections, which can capture the randomness and uncertainty of traffic accident forecasting in order to provide more precise results. METHODS : The authors propose a random parameter (RP) approach to overcome the limitation of the Count model that cannot consider the heterogeneity of the assigned locations or road sections. For the model's development, 55 intersections located in the Daejeon metropolitan area were selected as the scope of the study, and panel data such as the number of crashes, traffic volume, and intersection geometry at each intersection were collected for the analysis. RESULTS : Based on the results of the RP negative binomial crash prediction model developed in this study, it was found that the independent variables such as the log form of average annual traffic volume, presence or absence of left-turn lanes on major roads, presence or absence of right-turn lanes on minor roads, and the number of crosswalks were statistically significant random parameters, and this showed that the variables have a heterogeneous influence on individual intersections. CONCLUSIONS : It was found that the RP model had a better fit to the data than the fixed parameters (FP) model since the RP model reflects the heterogeneity of the individual observations and captures the inconsistent and biased effects.

• 제어로봇시스템학회논문지
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• 제20권9호
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• pp.950-956
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• 2014

In this paper, the real-time detection method of a DDP (Driving Direction Point) is proposed for an unmanned vehicle to safely follow the center of the road. Since the DDP is defined as a center point between two lanes, the lane is first detected using a web camera. For robust detection of the lane, the binary thresholding and the labeling methods are applied to the color camera image as image preprocessing. From the preprocessed image, the lane is detected, taking the intrinsic characteristics of the lane such as width into consideration. If both lanes are detected, the DDP can be directly obtained from the preprocessed image. However, if one lane is detected, the DDP is obtained from the inverse perspective image to guarantee reliability. To verify the proposed method, several experiments to detect the DDPs are carried out using a 4 wheeled vehicle ERP-42 with a web camera.