• Journal of the Korea Society for Simulation
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• v.17 no.4
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• pp.29-39
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• 2008

Recently, an ALV (Automated Lifting Vehicle) is studied as an efficient transporter, which can reduce the waiting time during ship operation in a container terminal. There are little of studies on an ALV system considering dynamic factors after analysing the cooperation between equipments. The performance of an ALV depends on self-loading & unloading of an ALV, vehicle’s interference, and occupancy of an available transfer point under dynamic environment. So, it is very difficult to evaluate the productivity of a container terminal with an ALV system. Therefore the simulation model with operational rules that be apt for an ALV system must be developed. Also the model has to consider the characteristics of interface operations and vehicle traffic. Supposing an container terminal with perpendicular layout, this study analyses the process of container handling operation and proposes operational rules such as the ALV dispatching, routing algorithm and so on for a model. We developed a simulation model for a container terminal with an ALV system using object-oriented simulation software, Anylogic.

• Journal of Positioning, Navigation, and Timing
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• v.4 no.3
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• pp.123-130
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• 2015

In this study, a carrier smoothed global positioning system / dead reckoning (CSGPS/DR) integrated system for high-precision trajectory estimation for the purpose of vehicle navigation was proposed. Existing code-based GPS has a low position accuracy, and carrier-phase differential global positioning system (CPDGPS) has a long waiting time for high-precision positioning and has a problem of high cost due to the establishment of infrastructure. To resolve this, the continuity of a trajectory was guaranteed by integrating CSGPS and DR. The results of the experiment indicated that the trajectory precision of the code-based GPS showed an error performance of more than 30cm, while that of the CSGPS/DR integrated system showed an error performance of less than 10cm. Based on this, it was found that the trajectory precision of the proposed CSGPS/DR integrated system is superior to that of the code-based GPS.

• Journal of Electrical Engineering and Technology
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• v.12 no.5
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• pp.1916-1924
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• 2017

Fossil oil, as the main energy of transportation, is destined to be exhausted. The electrification of transportation is a sustainable solution to the energy crisis, since electric power could be acquired from the inexhaustible sun, wind and water. Among all the problems that hinder the development of Electric Vehicle (EV) industry, charging issue might be the most prominent one. In this paper, the service process of a charging station with Battery Energy Storage System (BESS) is analyzed by means of $Cram{\acute{e}}r$ - Lundberg model which has been intensively utilized in ruin theory. The service quality is proposed in two dimensions: the service efficiency and the service reliability. The arrival rate and State of Charge (SOC) upon arrival are derived from 2009 National Household Travel Survey (NHTS). The simulations are performed to show how the service quality is determined by the system parameters such as the number of servers, the service rate, the initial capacity, the charge rate and the maximum waiting time. At last, the economic analysis of the system is conducted and the best combination of the system parameters are given.

• Journal of Korea Multimedia Society
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• v.11 no.8
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• pp.1051-1058
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• 2008

The advancement of technology for image processing and communications makes it possible for current traffic signal controllers and vehicle detection technology to make both emergency vehicle preemption and transit priority strategies as a part of integrated system. Present]y traffic signal control in crosswalk is controlled by fixed signals. The signal control keeps regular signals traffic even with no traffic, when there is traffic, should wait until the signal is given. Waiting time causes the risk of traffic accidents and traffic congestion in accordance with signal violation. To help reduce the risk of accidents and congestion, this paper explains traffic signal control system for the adaptive priority order so that signal may be preferentially given in accordance with the situation of site through the object detect images.

• IEMEK Journal of Embedded Systems and Applications
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• v.4 no.1
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• pp.42-49
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• 2009

Most Vehicular Ad hoc Network (VANET) applications rely heavily on broadcast transmission of traffic related information to all reachable nodes within a certain geographical area. Among various broadcast approaches, flooding is the first broadcasting technique. Each node rebroadcasts the received message exactly once, which results in broadcast storm problems. Some mechanisms have been proposed to improve flooding in Mobile Ad hoc Networks (MANET), but they are not effective for VANET and only a few studies have addressed this issue. We propose two distance-based and timer-based broadcast suppression techniques: 15P(15percent) and slotted 15P. In the first (distance based) scheme, node's transmission range is divided into three ranges (80%,15%and5%). Only nodes within 15% range will rebroadcast received packet. Specific packet retransmission range (15%) is introduced to reduce the number of messages reforwarding nodes that will mitigate the broadcaststorm. In the second (timer-based) scheme, waiting time allocation for nodes within 15% range isused to significantly reduce the broadcaststorm. The proposed schemes are distributed and reliedon GPS information and do not requireany other prior knowledge about network topology. To analyze the performance of proposed schemes, statistics such as link load and the number of retransmitted nodes are presented. Our simulation results show that the proposed schemes can significantly reduce link load at high node densities up to 90 percent compared to a simple broadcast flooding technique.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.8
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• pp.2473-2489
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• 2022

Urban development has brought about the increasing saturation of urban traffic demand, and traffic congestion has become the primary problem in transportation. Roads are in a state of waiting in line or even congestion, which seriously affects people's enthusiasm and efficiency of travel. This paper mainly studies the discrete domain path planning method based on the flow data. Taking the traffic flow data based on the highway network structure as the research object, this paper uses the deep learning theory technology to complete the path weight determination process, optimizes the path planning algorithm, realizes the vehicle path planning application for the expressway, and carries on the deployment operation in the highway company. The path topology is constructed to transform the actual road information into abstract space that the machine can understand. An appropriate data structure is used for storage, and a path topology based on the modeling background of expressway is constructed to realize the mutual mapping between the two. Experiments show that the proposed method can further reduce the interpolation error, and the interpolation error in the case of random missing is smaller than that in the other two missing modes. In order to improve the real-time performance of vehicle path planning, the association features are selected, the path weights are calculated comprehensively, and the traditional path planning algorithm structure is optimized. It is of great significance for the sustainable development of cities.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.1
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• pp.143-160
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• 2023

It is important to secure the golden time of emergency vehicles for quick responses in disaster situations, such as fire, rescue, and first aid. This study proposes plans Emergency Vehicle Preemption (EVP) based on the analysis of emergency vehicle operation to secure the golden time of emergency vehicles and increase driving safety. The emergency vehicle dispatch statistics, emergency vehicle traffic accident statistics, and survey were used for the analysis. As a result of the analysis, the frequency of dispatch of emergency vehicles and traffic accidents are increasing gradually, but the rate of securing the golden time of emergency vehicles is approximately half, indicating that improvement measures are urgent. In the questionnaire survey, most citizens consent to the necessity of introducing EVP. In addition, the criteria for the range of emergency vehicles that could provide EVP and the allowable time for waiting were derived. These results could be used to prepare EVP operation strategies, and it is expected to contribute to improving emergency vehicle operation safety and increasing the golden time securing rate through a rapid expansion of EVP.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.32-35
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• 1996

Traffic signal cycle optimization is one of the most efficient ways for reducing fuel consumption and improving vehicle waiting time of highsaturated traffic conditions. But most research focused on lowsaturated traffic conditions. Only a few studies have researched traffic control for highsaturated traffic conditions. In this paper reviews the problem of conventional traffic signal system and creates optimal traffic cycle of at the bottom traffic intersection using 27 fuzzy rules. Moreover, to prevent spillback, it can adapt control even though upper traffic intersection has a different saturation rate, road length, road slope and road width.

• Journal of Korean Society of Transportation
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• v.2 no.1
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• pp.33-68
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• 1984

수요감응교통체계는 승객들의 통행요구에 따라 보다 신속하고 효율적으로 안락하고 편리하게 경제적으로 교통서비스를 제공하는 것이다. 특히 기존의 공공교통수단이 미치지 못하는 저밀도 도시 지역의 통행수요를 만족시키는데 좋은 수단으로써 관심의 대상이 되고 있다. 즉 리무진 같은 소형차량을 이용하여 승객의 통행요청에 따라 개인적인 door-to-door 서비스를 제공하는 것이다. 본연구는 수요감응교통체계의 대안으로서 도시 서비스에 있어서 고정.노선변경승객 써비스에 대한 $\ulcorner$스케쥴 알고리즘$\lrcorner$을 개발하는데 목표를 둔바 목적함 수는 Waiting time, Riding time,Scheduled vehicle의 노선용량제한등과 같은 승객써비스 시 간제약에 대해서 각기 개별차량 여행과의 차를 극대화하여 보았다. 사용자중심 Sub-program과 PASS의 두 Sub-program으로 구성된 Simulation 모형을 활용할 경우 어떠 한 도시 써비스지역에서의 고정노선 혹은 변경노선 각각에 대해서 임시적인 차량운행의 감 응식 효율 증진에 크게 기여할 수 있는 것으로 나타났다.

• Journal of Korean Society of Transportation
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• v.14 no.3
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• pp.27-44
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• 1996

The purpose of the thesis is providing a new formulation for the transit assignment problem. The existing models dealing with the transit assignment problem don't consider the congestion effects due to the insufficient capacity of transit vehicles. Besides, these models don't provide solutions satisfying the Wardrop's user equilibrium conditions. The congestion effects are considered to be concentrated at the transit stops. For the transit lines, the waiting times at the transit stops are dependent on the passenger flows. The new model suggests the route section cost function analogous to the link performance function of the auto assignment to reflect the congestion effects in congested transit network. With the asymmetric cost function, the variational inequality programming is used to obtain the solutions satisfying Wardrop's condition. The diagonalization algorithm is introduced to solve this model. Finally, the results are compared with those of EMME/2.