• Journal of the Korea Institute of Information Security & Cryptology
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• v.34 no.2
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• pp.217-228
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• 2024

LiDAR(Light Detection And Ranging) sensors, which play a pivotal role among cameras, RADAR(RAdio Detection And Ranging), and ultrasonic sensors for the safe operation of autonomous vehicles, can recognize and detect objects in 360 degrees. However, since LiDAR sensors use lasers to measure distance, they are vulnerable to attackers and face various security threats. In this paper, we examine several security threats against LiDAR sensors: relay, spoofing, and replay attacks, analyze the possibility and impact of physical jamming attacks, and analyze the risk these attacks pose to the reliability of autonomous driving systems. Through experiments, we show that jamming attacks can cause errors in the ranging ability of LiDAR sensors. With vehicle-to-vehicle (V2V) communication, multi-sensor fusion under development and LiDAR anomaly data detection, this work aims to provide a basic direction for countermeasures against these threats enhancing the security of autonomous vehicles, and verify the practical applicability and effectiveness of the proposed countermeasures in future research.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.5
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• pp.1969-1980
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• 2013

The Traffic congestion is caused by the increasing traffic demand. Thus, economic losses have been increasing every year. To solve these problems, car sharing and rental car systems that are equipped with IT technologies emerge. Car sharing has many advantages-the alleviation of the traffic congestion, the saving of maintenance cost for cars, the reduction of car possessiveness, the solution for the hassle of car ownership, for business and personal duty, and the improvement of connectivity between public transportations-. The goal of the car sharing is to achieve low-carbon and eco-friendly transportation. In this study, we review papers related to the car sharing system and the cost system of traffic systems. We estimate the optimal cost of the cloud traffic system that is one of the car sharing services. We suggest a methodology to estimate operational cost and use cost through the analysis of cost system between similar traffic means. The range of the maximum and minimum cost was determined through the comparison and analysis of similar traffic means. Expected demand and the cost that people are willing to pay were estimated through optimized value pricing. The minimum cost per hour that was compared to the cost of rental car was estimated at 5,333 won and the maximum cost per hour that was compared to taxi cost was estimated at 17,700 won. The cost for users was estimated at 6,930 won. The cost of 50% demands was estimated at 6,550won. Future studies should analyze service hours of users, weather, demand pattern and trend and consider them into the cost estimation.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.1
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• pp.186-195
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• 2017

Recently, autonomous vehicles have been studied actively. There are various technologies such as ITS, Connected Car, V2X and ADAS in order to realize such autonomous driving. Among these technologies, it is particularly important to recognize where the vehicle is on the road in order to change the lane and drive to the destination. Generally, it is done through GPS and camera image processing. However, there are limitations on the reliability of the positioning due to shaded areas such as tunnels in the case of GPS, and there are limitations in recognition and positioning according to the state of the road lane and the surrounding environment when performing the camera image processing. In this paper, we propose that LED lights should be installed for autonomous vehicles in tunnels which are shaded area of the GPS. In this paper, we show that it is possible to measure the position of the current lane of the autonomous vehicle by analyzing the color temperature after constructing the tunnel LED lighting simulation environment which illuminates light of different color temperature by lane. Based on the above, this paper proposes a lane positioning technique using tunnel LED lights.

• Journal of Korean Society of Transportation
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• v.21 no.2
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• pp.7-16
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• 2003

To minimize the death and injury by a collision, the installation of an air bag is recommended as a mandatory practice together with the wearing of the seat belt. By using simulated collision experiments, this research focused on the effect of an air bag and seat belt on the driver safety. The vehicle deceleration characteristics were obtained from impact experiment. LSDYNA, a software program for vehicle collision analysis, and MADYMO. a software program for driver motion after collision, were used for simulated experiment. Four cases such as air bag installed and seat belt wearing (case A), air bag installed but seat belt not wearing (case B), air bag not installed but seat belt wearing (case C), air bag not installed and seat belt not wearing (case D) were analyzed. The impact of acceleration on the injury of driver's head was analyzed by Head Injury Criterion (HIC) as well. It was found that having air bag and wearing seat belt effectively reduced driver's head injury about 52.9% to 70.5% compared with the case of having neither air bag nor wearing seat belt.

• Journal of Energy Engineering
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• v.23 no.2
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• pp.28-34
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• 2014

Automatic transmission fluid (ATF) is used for automatic transmissions in the vehicle as the characterized fluid. Recently, the vehicle manufacture usually guarantee for fluid change over 80000~100000 km mileage or no exchange, but most drivers usually change ATF below every 50000 km driving in Republic of Korea. It can cause to raise environmental contamination by used ATF and increase the cost of driving by frequently ATF change. In this study, we investigate the various physical properties such as flash point, fire point, pour point, kinematic viscosity, cold cranking simulator, total acid number, and metal component concentration for fresh and used ATF after driving (50000 km, 100000 km). The result showed that the total acid number, pour point, Fe, Al and Cu component had increased than fresh ATF, but 2 kind of used oil (50000 km and 100000km) had similar physical values and metal component concentration.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.419-425
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• 2019

The objective of this study was to investigate the cooling performance characteristics of a hybrid refrigeration system in a heavy duty vehicle. The tested hybrid refrigeration system had additionally an electric compressor besides the present mechanical compressor for selective use according to the operating conditions. The applied electric compressor was a scroll type and with 18.0 cc displacement. In order to analyze the performance characteristics of the hybrid refrigeration system with respect to the cooling capacity and Coefficient of Performance (COP), other components, including two different types of compressors, were installed and tested under various operating conditions such as compressor speed and air flow rate of the evaporator. When the electric compressor was operated at 4,500 rev/min, the cooling capacity was about 4.0kW and COP was 3.5. When the mechanical compressor was operated, whereas the cooling capacity was higher than the electric controlled compressor, COP was lower due to the larger displacement and higher power consumption. To analyze the hybrid system operating characteristics due to reasonable cooling capacity with electric compressor operation, the mechanical compressor and electric compressor were operated by turns every 10 minutes under certain system operating conditions. Because surge pressure occurred when both compressors were switched on, the operating strategy required some time to balance the system pressure.

• Journal of Korean Society of Transportation
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• v.19 no.1
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• pp.101-114
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• 2001

Transportation enterprises should maintain constant and qualitative operation. Thus, in short period, transportation enterprises don't change supply in accordance with demand. In the result, transportation enterprises don't reduce operation in spite of management deficit at will. In freight transportation type, less-than-truckload(LTL) has more relation with above transportation feature than truckload(TL) does. Because freight transportation supply of TL is more flexible than that of LTL in correspondence of freight transportation demand. Relating to above mention, it appears that shortage of road and freight terminal of LTL is larger than that of TL. Especially in road and freight terminal comparison, shortage of freight terminal is larger than that of road. Shortage of road is the largest in 1990, and improved after-ward. But shortage of freight terminal is serious lately. So freight terminal needs more expansion than road, and shows better investment condition than road. Freight terminal expansion brings road expansion in LTL, on the contrary, freight terminal expansion substitutes freight terminal for road in TL. In transportation revenue, freight terminal's contribution to LTL is larger than that to TL. However, when we adjust quasi-fixed factor - road and freight terminal - to optimal level in the long run, in TL, diseconomies of scale becomes large, but in LTL, economies of scale becomes large. Consequently, it is necessary for TL to make counterplans to activate management of small size enterprises and owner drivers. And LTL should make use of economies of scale by solving the problem, such as nonprofit route, excess of rental freight handling of office, insufficiency of freight terminal, shortage of driver, and unpreparedness of freight insurance.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.3 no.2 s.5
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• pp.19-28
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• 2004

This paper shows how to compensate the skew from the traffic sign included in the natural image and extract the text. The research deals with the Process related to the array image. Ail the process comprises four steps. In the first fart we Perform the preprocessing and Canny edge extraction for the edge in the natural image. In the second pan we perform preprocessing and postprocessing for Hough Transform in order to extract the skewed angle. In the third part we remove the noise images and the complex lines, and then extract the candidate region using the features of the text. In the last part after performing the local binarization in the extracted candidate region, we demonstrate the text extraction by using the differences of the features which appeared between the tett and the non-text in order to select the unnecessary non-text. After carrying out an experiment with the natural image of 100 Pieces that includes the traffic sign. The research indicates a 82.54 percent extraction of the text and a 79.69 percent accuracy of the extraction, and this improved more accurate text extraction in comparison with the existing works such as the method using RLS(Run Length Smoothing) or Fourier Transform. Also this research shows a 94.5 percent extraction in respect of the extraction on the skewed angle. That improved a 26 percent, compared with the way used only Hough Transform. The research is applied to giving the information of the location regarding the walking aid system for the blind or the operation of a driverless vehicle

• Journal of Korea Port Economic Association
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• v.33 no.3
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• pp.17-34
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• 2017

This study aims to analyze the freight transport demand and benefit for the introduction of an automated freight transport system focusing on the Global Industry and Logistics City (GILC) in Busan. In pursuit of this aim, four alternatives were calculated - using the freight volume estimating methods and included, the number of businesses, the number of employees set up, future estimated cargo volume, and switched volume from other transport modes into the GILC. Economic benefits were analyzed against social benefits and costs accordingly. The result of the freight transport demand forecast found, the cargo volume of "Alternative 2-1" to be the most advantageous, applying the number of employee unit method and proportion of employees in Gangseo-gu, Busan. In addition to the conventional analysis of direct benefit items (reduction of transport time, traffic accidents and environmental costs), this study also considered additional benefit items (congestion costs savings, and road maintenance costs in terms of opportunity cost). It also considered advanced value for money research in guidance on rail appraisal of U.K, Federal Transport Infrastructure Plan 2003 of Germany, and RailDec of the United States. The study aims to further contribute to estimating minimum cargo transport demands and assess the economic feasibility of the introduction of new intermodal automated freight transport systems in the future.

• The Journal of Engineering Geology
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• v.12 no.1
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• pp.53-61
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• 2002

Cut-slope due to the road construction is one of the most significant problems in the domestic case, that is, 70% of the land is covered by mountain. Moreover, typhoons or heavy rains concentrated in summer season causes the failure of cut-slope. Rock-fall and soil slope failure take 40.8% and 29.5% out of the entire domestic cut-slope failure, respectively. Rock-fall is quickly occurred by the free fall or rolling of rock fragments generally in the upper slope. Soil slope failure produces a clastics-flow and increases casualty especially when caused by heave rainfall because the velocity of the movement is verb high. Considering the car speed and rock-fall velocity, it will take a life in a moment. This study analyzes a set of field data of most recently collapsed domestic road cut-slopes to characterize these cut-slopes and the nature of rock-falls and clastics flows at each site. Based on the results, design criteria for a road alarm system are proposed, considering the relationship between the time required for clastics-flow and the velocity and braking distance of a cat at the incidence. The road alarm system proposed herein would operate instantly after a rock-fall and it will minimize damages, by warning drivels approaching to the collapse or collapsing location in advance.