• Annual Conference of KIPS
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• 2020.11a
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• pp.698-701
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• 2020

여러 대의 자율주행 차량이 하나의 그룹을 형성하여 주행하는 군집주행은 미래 고속도로 교통 시스템의 핵심 기술이다. 이러한 군집주행에서 발생할 수 있는 다양한 상황에서의 안전을 고려하는 일은 단독 자율 주행에서의 경우보다 더 어렵다. 다양한 군집주행의 안전 위협 요인 중, 의도하지 않은 동작으로부터 자율주행 차량의 안전성을 향상하는 방법을 가이드하기 위하여 새로운 표준 ISO/PAS 21448이 제정되었다. 본 논문에서는 ISO/PAS 21448 표준이 다루는 시나리오를 통해 군집주행에서 발생할 수 있는 의도하지 않은 상황의 극복을 위한 방법을 제시하였다. 특히 군집주행 시뮬레이터인 VENTOS를 이용하여 본 논문에서 제시하는 방법이 안전한 군집주행이라는 목표를 달성할 수 있음을 확인하였다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.4
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• pp.693-702
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• 2002

The aim of this study is to develop a 3-dimensional dynamic analysis model, capable of considering the interaction between vehicles and bridges more accurately. The dynamic analysis model is developed with the high-speed train (KTX) and a 2-span continuous prestressed concrete box girder bridge with a double track. The 20-car model is developed using the moving vehicle model for the regular trainset. Three-dimensional frame elements are used for the bridge model. Using the developed models, a dynamic behavior analysis program is coded. The analytical results are compared with the dynamic field test results and found to be valid to yield quite accurate dynamic responses. Based on the results of this study, the hybrid model, made up of the moving vehicle model for the heaviest power car and the moving force model for the other cars, is quite simple and effective without loosing the accuracy that much. Under the coincidence condition of two trains traveling with resonance velocity in the opposite directions, it is necessary to check not only the dynamic responses of the bridge with one-way traffic but those with two- way coincidence.

• Journal of Korean Society of Steel Construction
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• v.24 no.1
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• pp.47-58
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• 2012

Dynamic behaviors of a corrugated steel plate tunnel lining system are examined under wind loads due to passing vehicles. Applied wind loads are simulated by applying the time functions as a vehicle moves through the tunnel. Wind loads are described by the pressure and suction as a vehicle arrives and leaves target positions in the tunnel. The tunnel lining is modeled using the simplified shell elements that retain the characteristics of the corrugated shapes. The displacements of the tunnel lining are evaluated under various conditions regarding wind velocity and the passing vehicles. The responses are found to increase as the vehicle velocity and wind velocity increase. A maximum displacement of 25mm occurs when two vehicles are crossing at the speed of 120km/h. A row of vehicles running consecutively minimally affects the dynamic responses with less than 2.5% of the dynamic responses enlarged and attributed to one running vehicle. It should be noted that the dynamic responses of the tunnel lining should be considered when there is no shotcrete applied.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.475-478
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• 2009

안개가 교통사고를 유발시키는 원인을 살펴보면 운전자의 시거와 밀접한 관련이 있다. 짙은 안개가 발생하게 되면 돌발상황이 발생하였을 때 도로를 주행하던 차량이 안전하게 정지하기 위해서 필요한 최소 정지거리가 증가하게 되나 안개로 인한 시정이 나빠지게 되어서 사고발생확률이 높은 것이다. 또한 안전한 시거가 확보되지 않기 때문에 단독사고 발생 후 뒤따르던 차량이 전방을 확인하지 못한 상황에서 연쇄 충돌하게 되어 사고가 대형화된다. 이에 본 연구에서는 IT기술인 RFID와 USN을 이용하여 안개로 인한 시정거리에 따라 도로에 있는 과속카메라가 도로주행 한계속도를 자기 스스로 판단하여 자동조절하게 만들고 변경된 한계속도를 그 도로를 이용하는 차량운전자 휴대폰에 문자로 전송해주고 도로전광판에서도 정확하게 주행속도정보를 볼 수 있게 한다. 그리하여 도로주행 한계속도를 어기는 차량에는 범칙금을 부과하게 만든다. 본 연구를 통해 안개에 대한 교통사고의 위험을 줄이고 사회적 경제적으로 이익이 되도록 하기위해 기상상태 변화에 따른 USN 기반의 도로주행 한계속도 지능적 조정 관리시스템을 제안하고자 한다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.739-748
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• 2013

In this study, analytical works for the induced winds due to traveling vehicles on highway have been conducted by Computation Fluid Dynamics (CFD). The traveling condition was considered in two cases: (a) single direction and (b) bi-direction. The analysis was focused on the effects of the induced winds on the upper part of a median strip while the aerodynamic characteristics of the vehicles were directly analyzed in the previous studies. From the analysis results, it has been found that the maximum magnitude of the induced winds was 2.2 m/s when the vehicles travel with the speed of 50 km/h. Additionally, 4.0 m/s and 5.3 m/s were obtained with the speed of 90 km/h and 120 km/h, respectively. Especially, the induced winds was generated about 84% of the vehicle speed at 1.0 m above from the median strip when the vehicles travel with the speed of 120 km/h. The induced winds was maintained during the very short period while the traveling. conclusively, it is noted that the wind power generation can be possible by using the small-sized wind power generators installed on median strips throughout the analytical results in this study.

• The Journal of the Acoustical Society of Korea
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• v.18 no.2
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• pp.11-17
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• 1999

This paper proposes an observation probability smoothing technique for the robustness of a discrete hidden Markov(DHMM) model based speech recognizer. Also, an appropriate noise robust processing in car environment is suggested from experimental results. The noisy speech is often mislabeled during the vector quantization process. To reduce the effects of such mislabelings, the proposed technique increases the observation probability of similar codewords. For the noise robust processing in car environment, the liftering on the distance measure of feature vectors, the high pass filtering, and the spectral subtraction methods are examined. Recognition experiments on the 14-isolated words consists of the Korean digits and command words were performed. The database was recorded in a stopping car and a running car environments. The recognition rates of the baseline recognizer were 97.4% in a stopping situation and 59.1% in a running situation. Using the proposed observation probability smoothing technique, the liftering, the high pass filtering, and the spectral subtraction the recognition rates were enhanced to 98.3% in a stopping situation and to 88.6% in a running situation.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2009.11a
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• pp.168-173
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• 2009

The purpose of this study was to analyze behavioral patterns of elderly residents and to identify the characteristics of using furniture and home appliances by elderly-headed households. For this purpose, field studies that included observation and open-ended interview were conducted with 52 households. The data was analyzed with frequency, chi-square test by SPSS 14.0 for windows. The major findings of this study were that: 1) Elderly households had more sitting-down style furniture which was a traditional living mode than western style furniture. 2) They experienced inconvenience to use home appliances that were not designed for the aged. 3) Their behavioral patterns were related with family type and income.

• Electronics and Telecommunications Trends
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• v.30 no.5
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• pp.39-48
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• 2015

최근 스마트카 기술은 안전운전지원 센서 기반의 단독형 시스템에서 도로 인프라와 빅 데이터를 기반으로 ICT와 연계하여 교통흐름을 예측하고 대응할 수 있는 협력형 자율주행 서비스 개발로 발전하고 있다. 협력형 자율주행 서비스를 실현하거나, IoT 환경과 스마트카의 융합을 위해서는 스마트카에서 커넥티비티 역량이 무엇보다도 중요하게 되었으며 이를 위한 요소기술로 차량용 이더넷, V2X(Vehicle to Everything) 네트워킹, 네트워크 보안기술을 꼽을 수 있다. 본고에서는 스마트카에 적용되는 차량 내부 네트워크 및 게이트웨이, V2X 네트워킹 및 보안에 관한 최근 표준 기술동향 및 이슈를 살펴보고자 한다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.14 no.4
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• pp.309-320
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• 2012

Dynamic behaviors of the tunnel linings of curved tunnels with various curvatures are investigated to examine the effect of wind loads due to passing vehicles. In the case without backfill, the responses of the tunnel lining should be considered to examine the clearance of the lining. A steel tunnel lining is selected to see the influence of the wind load upon the tunnel lining more clearly. The wind pressure upon the lining is simplified into the pressure and suction while the vehicle passing the loading positions. As the radius of curvature decreases, the response decreases, showing that the strength against the deformation is found to increase since the asymmetry of the deformation shape is reduced. It is found that the responses increase as the passing vehicle speed increases.

• Journal of Korean Society of Transportation
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• v.32 no.1
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• pp.1-12
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• 2014

The tier 3 methodology used in estimation of greenhouse gas emissions from road sectors is based on mileage data. However, such data can neither accurately represent the mileage of regional unit nor have sufficient integrated data reflecting the characteristics by region, vehicle type, fuel type and road type. Such estimation of greenhouse gas emissions is not reliable. Accordingly, the purpose of this study is, firstly to accumulate activity data based on distance traveled which enables us to accurately estimate the amount of green gas emitted by regional unit(emission point), and secondly, to develop a methodology for estimation of greenhouse gas emissions using these data. To do this, the study utilizes the mileage data of Korea Transportation Safety Authority(TS), statistics of registered motor vehicles, statistical yearbook of traffic volume from the Ministry of Land, Infrastructure and Transport(MLIT), the Korea Transport Database of the Korea Transport Institute(KOTI), and average road speed by local government. Methodology for estimation by local government level(emission point) is meaningful, because it reflects traffic pattern data including flow in and out and internal traffics. Finally, to verify the methodology presented in this study, it is applied to Seoul. Both greenhouse gas estimates, one by multiplying the average mileage and the number of registered vehicles and the other by multiplying traffic volume and road extension, are less than the amount estimated by the methodology presented in this study.