• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.7
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• pp.2534-2540
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• 2010

In this paper we propose contents and results on installation and commissioning test for ATP on-board unit, which has propelled as one of the research projects, so called, "Reliability assessment and operation technology development for Korean-type tilting trains" in order to ensure the safety and operation efficiency of tilting trains. In KRRI, we have developed tilting trains for the speed-up of existing lines and for the passenger service improvement where the KTX is not available. And we also make progress the operation trial test at the speed of 10km with the use of ATS units, used in existing lines, for the purpose of the reliability assessment of the developed tilting trains. In MLTM, they have decided to accelerate the speed at more than 200km/h for the 7 existing lines including Jungang-line and Chungbuk-line where KTX has not operated. According to this decision, Train control system is to be changed from ATS to ATP. We should install an ATP on-board unit in tilting trains and verify the operational suitability. Therefore, we have installed and tested the same ATP on-board unit on tilting trains that used in the ATP construction project on Gyeongbu-line and Honam-line.

• Review of KIISC
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• v.33 no.4
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• pp.23-29
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• 2023

대부분의 임베디드 시스템은 기계장치와 전자기기 장치가 함께 작동되는 물리 장치로써, 이기종 네트워크, 복잡한 보안체계 등을 고려하여 가상화 기반 사이버훈련 환경이 구성되어야 한다. 또한, 차량을 대상으로 물리적인 실험환경에서 모의침투 등 사이버훈련을 수행한다는 것은 교통사고를 비롯한 안전사고 발생에 있어 위험이 존재한다. 본 논문에서는 가상 개발환경에서의 공격 기반 차량용 사이버훈련 프레임워크를 제안하고자 한다. 먼저, 공격 기반 차량용 사이버훈련 프레임워크의 작동은 자동 활성화되는 가상의 CAN 네트워크 인터페이스로 시작된다. 가상의 CAN 네트워크 인터페이스는 가상 머신에서 간단한 부트스트랩 명령어 실행을 통해 파이썬 패키지와 Ubuntu 서비스 목록 설치 명령이 자동으로 실행되면서 설치된다. 이후 내부 네트워크 시뮬레이터와 공격모듈과 관련된 UI가 자동으로 Ubuntu Systemd에 의해 백그라운드에서 실행되어 시작과 동시에 준비 상태를 유지하게 된다. 사이버훈련 UI 내 공격 모듈은 사용자에 의한 공격 선택 및 파라미터 셋팅 이후 차량의 이상 상태를 사이버훈련 UI에 다시 출력되게 된다. 본 논문에서 제안하는 가상 개발환경 기반의 차량용 사이버훈련 프레임워크는 자율주행 차량 사고의 위험이나 다른 특수한 제약 없이 사용자의 학습 경험을 확장시킬 수 있다. 또한, 기존의 가상화 기반 사이버훈련 교육 콘텐츠와는 달리 일반 사용자들이 접근하기 쉬운 형태로 확장 개발이 가능하다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2023.01a
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• pp.35-38
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• 2023

포트홀은 주행하는 자동차와 접촉이 이뤄지면 차체나 운전자에게 충격을 주고 제어를 잃게 하여 도로 위 안전을 위협할 수 있다. 포트홀의 검출을 위한 국내 동향으로는 진동을 이용한 방식과 신고시스템 이용한 방식과 영상 인식을 기반한 방식이 있다. 이 중 영상 인식 기반 방식은 보급이 쉽고 비용이 저렴하나, 컴퓨터 비전 알고리즘은 영상의 품질에 따라 정확도가 달라지는 문제가 있었다. 이를 보완하기 위해 영상 인식 기반의 딥러닝 모델을 사용한다. 따라서, 본 논문에서는 사전 학습된 딥러닝 모델의 정확도 향상을 위한 Feature Level Ensemble 기법을 제안한다. 제안된 기법은 사전 학습된 CNN 모델 중 Test 데이터의 정확도 기준 Top-3 모델을 선정하여 각 딥러닝 모델의 Feature Map을 Concatenate하고 이를 Fully-Connected(FC) Layer로 입력하여 구현한다. Feature Level Ensemble 기법이 적용된 딥러닝 모델은 평균 대비 3.76%의 정확도 향상을 보였으며, Top-1 모델인 ShuffleNet보다 0.94%의 정확도 향상을 보였다. 결론적으로 본 논문에서 제안된 기법은 사전 학습된 모델들을 이용하여 각 모델의 다양한 특징을 통해 기존 모델 대비 정확도의 향상을 이룰 수 있었다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.6
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• pp.41-50
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• 2011

This article is concerned with the technology to provide car driver the car's status which are composed of car trouble code in car engine and many sensors. In addition, it installs vehicle diagnostic programs on wireless communication's portable device, for example, Smart phone, PDA, PMP, UMPC. As a result, this is to provide car manager with many information of car sensors when we go to car maintenance. it can monitor relevant information on vehicle by portable device in real time, alert drivers with specific messages and also enable them to address abnormalities immediately. Moreover, the technology could help the drivers who perhaps don't know very well about their vehicles to drive safely and economically as well; the reason is because the whole system is composed of just Vehicle-information collecting device and personal wireless communication's portables and transfers the relating data to server computers through wireless network in order to handle information on vehicles. This technology make us monitor vehicle's running, failure and disorder by using wireless communication's portable device. Finally, this study system is composed of a lot of application to display us the car's status which get car's inner sensor information while driving a car.

• Smart Media Journal
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• v.13 no.3
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• pp.18-26
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• 2024

Road surface monitoring is essential for maintaining road environment safety through managing risk factors like rutting and crack detection. Using autonomous driving-based UGVs with high-performance 2D laser sensors enables more precise measurements. However, the increased energy consumption of these sensors is limited by constrained battery capacity. In this paper, we propose a fusion sensor system for efficient surface monitoring with UGVs. The proposed system combines color information from cameras and depth information from line laser sensors to accurately detect surface displacement. Furthermore, a dynamic sampling algorithm is applied to control the scanning frequency of line laser sensors based on the detection status of monitoring targets using camera sensors, reducing unnecessary energy consumption. A power consumption model of the fusion sensor system analyzes its energy efficiency considering various crack distributions and sensor characteristics in different mission environments. Performance analysis demonstrates that setting the power consumption of the line laser sensor to twice that of the saving state when in the active state increases power consumption efficiency by 13.3% compared to fixed sampling under the condition of λ=10, µ=10.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.8
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• pp.26-33
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• 2017

Vehicle communication can facilitate efficient coordination among vehicles on the road and enable future vehicular applications such as vehicle safety enhancement, infotainment, or even autonomous driving. In the $3^{rd}$ Generation Partnership Project (3GPP), many studies focus on long term evolution (LTE)-based vehicle communication. Because vehicle speed is high enough to cause severe channel distortion in vehicle-to-vehicle (V2V) environments. We can utilize channel estimation methods to approach a reliable vehicle communication systems. Conventional channel estimation schemes can be categorized as least-squares (LS), decision-directed channel estimation (DDCE), spectral temporal averaging (STA), and smoothing methods. In this study, we propose a smart channel estimation scheme in LTE-based V2V environments. The channel estimation scheme, based on an LTE uplink system, uses a demodulation reference signal (DMRS) as the pilot symbol. Unlike conventional channel estimation schemes, we propose an adaptive smoothing channel estimation scheme (ASCE) using quadratic smoothing (QS) of the pilot symbols, which estimates a channel with greater accuracy and adaptively estimates channels in data symbols. In simulation results, the proposed ASCE scheme shows improved overall performance in terms of the normalized mean square error (NMSE) and bit error rate (BER) relative to conventional schemes.

• KIPS Transactions on Software and Data Engineering
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• v.6 no.11
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• pp.537-542
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• 2017

Aggressive driving is a major cause of car accidents. Previous studies have mainly analyzed young driver's aggressive driving tendency, yet they were only done through pure clustering or classification technique of machine learning. However, since elderly people have different driving habits due to their fragile physical conditions, it is necessary to develop a new method such as enhancing the characteristics of driving data to properly analyze aggressive driving of elderly drivers. In this study, acceleration data collected from a smartphone of a driving vehicle is analyzed by a newly proposed ECA(Enhanced Clustering method for Acceleration data) technique, coupled with a conventional clustering technique (K-means Clustering, Expectation-maximization algorithm). ECA selects high-intensity data among the data of the cluster group detected through K-means and EM in all of the subjects' data and models the characteristic data through the scaled value. Using this method, the aggressive driving data of all youth and elderly experiment participants were collected, unlike the pure clustering method. We further found that the K-means clustering has higher detection efficiency than EM method. Also, the results of K-means clustering demonstrate that a young driver has a driving strength 1.29 times higher than that of an elderly driver. In conclusion, the proposed method of our research is able to detect aggressive driving maneuvers from data of the elderly having low operating intensity. The proposed method is able to construct a customized safe driving system for the elderly driver. In the future, it will be possible to detect abnormal driving conditions and to use the collected data for early warning to drivers.

• Journal of Internet Computing and Services
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• v.17 no.6
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• pp.81-91
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• 2016

VANET is one of the most developed technologies many people have considered a technology for the next generation. It basically utilizes the wireless technology and it can be used for measuring the speed of the vehicle, the location and even traffic control. With sharing those information, VANET can offer Cooperative ITS which can make a solution for a variety of traffic issues. In this way, safety for drivers, efficiency and mobility can be increased with VANET but data between vehicles or between vehicle and infrastructure are included with private information. Therefore alternatives are necessary to secure privacy. If there is no alternative for privacy, it can not only cause some problems about identification information but also it allows attackers to get location tracking and makes a target. Besides, people's lives or property can be dangerous because of sending wrong information or forgery. In addition to this, it is possible to be information stealing by attacker's impersonation or private information exposure through eavesdropping in communication environment. Therefore, in this paper we propose Privacy Assurance Architecture for VANET to ensure privacy from these threats.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.475-486
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• 2021

The purpose of this study was to propose a policy direction to improve the service of public bicycles in Seoul by identifying the physical characteristics that affect the satisfaction level in the Seoul Metropolitan Government's public bicycle use environment. To this end, a survey was conducted on users regarding their experiences using public bicycles in Seoul, and the responses of 567 people were analyzed. IPA analysis and ordinal logistic analysis were used. An analysis of the Seoul Metropolitan Government's public bicycle IPA showed that the satisfaction level was lower than that of importance in all categories. Among them, the most urgent need for improvement was the installation of bicycle roads, improved connectivity of bicycle roads, improved road management, classification of roads and bicycle roads, improved safety during night driving, and low satisfaction levels. Second, an analysis of the factors affecting the satisfaction in the public bicycle use environment showed that the model's explanatory power increased significantly from 0.062 to 0.437 after incorporating perceived variables, confirming that the perceived neighborhood environment characteristics are an important variable for determining the satisfaction level in the public bicycle use environment, among the perceived neighborhood environmental characteristics, accessibility, convenience, manageability.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.3A
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• pp.211-219
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• 2010

The design concept of high speed railway bridges is applied to a method for increasing the stiffness of existing bridge structures considering the impact factor by a static load. Generally, the process of structural design would be relied upon an advanced foreign technology. However, the dynamic amplification factor (DAF) and dynamic capacity assessment of high speed railway bridges may be conducted essentially a detailed estimation because the resonance phenomenon is affected by the long length (380 m) and high speed (300 km/h) moving of a high speed railway (Korea Train eXpress: KTX). Therefore, this study will be examined the dynamic capacity of the typical PSC Box Girder high speed railway bridge efficiently, and offered the basic information for the reasonable structural design. For this, the static analysis is conducted considering the load line diagram of KTX based upon existing references. In addition, the KTX moving load is transformed into the time series load considering various analytical variables. The time history analysis is assessed reasonable using the transformed time series load. At that time, analytical variables for calculating the time series load are considered loading node distance, time increment and KTX velocity variation etc. The dynamic capacity of the PSC Box Girder high speed railway bridge is examined based upon the FE analysis result systematically. The structural safety is assessed quantitatively in accordance with the related regulation of the inside and outside of the country.