• International Journal of Automotive Technology
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• v.7 no.1
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• pp.25-34
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• 2006

For decades, simulation technique has been well validated in areas such as computer and communication systems. Recently, the technique has been much used in the area of transportation and traffic forecasting. Several methods have been proposed for investigating complex traffic flows. However, the dynamics of vehicles and diversities of driver characteristics have never been considered sufficiently in these methods, although they are considered important factors in traffic flow analysis. In this paper, we propose a traffic simulation tool called Multi-Agent for Traffic Simulation with Vehicle Dynamics Model (MATDYMO). Road transport consultants, traffic engineers and urban traffic control center managers are expected to use MATDYMO to efficiently simulate traffic flow. MATDYMO has four sub systems: the road management system, the vehicle motion control system, the driver management system, and the integration control system. The road management system simulates traffic flow for various traffic environments (e.g., multi-lane roads, nodes, virtual lanes, and signals); the vehicle motion control system constructs the vehicle agent by using various vehicle dynamic models; the driver management system constructs the driver agent capable of having different driving styles; and lastly, the integrated control system regulates the MATDYMO as a whole and observes the agents running in the system. The vehicle motion control system and driver management system are described in the companion paper. An interrupted and uninterrupted flow model were simulated, and the simulation results were verified by comparing them with the results from a commercial software, TRANSYT-7F. The simulation result of the uninterrupted flow model showed that the driver agent displayed human-like behavior ranging from slow and careful driving to fast and aggressive driving. The simulation of the interrupted flow model was implemented as two cases. The first case analyzed traffic flow as the traffic signals changed at different intervals and as the turning traffic volume changed. Second case analyzed the traffic flow as the traffic signals changed at different intervals and as the road length changed. The simulation results of the interrupted flow model showed that the close relationship between traffic state change and traffic signal interval.

• Journal of Korean Society of Transportation
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• v.27 no.3
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• pp.71-77
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• 2009

The ubiquitous transportation system environments make it possible to collect each vehicle's position and velocity data and to perform more sophisticated traffic flow management at individual vehicle or platoon level through V2V and V2I communications. The VISSIM simulation experiments were performed to address the issues in developing the preventive congestion management algorithm proposed in the companion paper. Traffic flow stability measures were developed based on the platoon profile, which enables us to explicitly consider traffic flow stability in traffic flow management. Traffic flow management strategies according to the traffic flow states were proposed: Maintain the equilibrium speed for free flow state, maintain the traffic flow stability by platoon control for critical state, and surpress the shock wave propagation for congested state. And finally potential benefit of the proposed traffic flow management scheme was evaluated based on the simulation experiment results. It is considered that extensive field experiments should be performed to confirm the simulated results.

• Journal of the Korea Society for Simulation
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• v.11 no.4
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• pp.43-55
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• 2002

Vessel traffic safety management means the managerial technical measures for improving the marine traffic safety in general terms. The main flow of vessel traffic safety management is that: 1) Traffic Survey, 2) Replay by Marine Traffic Flow Simulation, 3) Quantitative Assessment, 4) Policy Alternatives, 5) Prediction·Verification. In the management of vessel traffic safety, it is most important to establish assessment models that can numerically estimate the current safety level and quantitatively predict the correlation between the measures to be taken and the improvement of safety and the reduction of ship handling difficulties imposed on mariners. In this paper, the replay model for traffic flow simulation was made using marine traffic survey data, and the present traffic situation became replay in the computer. An attempt was made to rate the current safety of ports and waterways by applying the Environmental Stress model. And, as a countermeasure for traffic management, by taking of, the promotion of total traffic congestion in early morning rush hour, the correlation between traffic control rate and the reduction in ship handling difficulties imposed on mariners was predicted quantitatively.

• Journal of Korean Society of Transportation
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• v.26 no.3
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• pp.179-186
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• 2008

It is crucial in traffic flow management to maintain productivity and the traffic stability at the same time especially under congested traffic conditions. This issue has not been explicitly addressed under the intelligent transportation system environments. However, the ubiquitous transportation system environments make it possible to collect the data for each vehicle's position and velocity and to perform more sophisticated traffic flow management at individual vehicle or platoon level through V2V and V2I communications. In this paper, a preventive traffic flow management scheme is proposed, in which the objective is to maintain traffic flow stability while the productivity of the system is not decreased. The management scheme is proposed based on Greenshield's model because it is simple and easy to handle. It is considered that further research should be performed to evaluate the various traffic flow models.

• International Journal of Automotive Technology
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• v.7 no.2
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• pp.145-154
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• 2006

In the companion paper, the composition and structure of the MATDYMO (Multi-Agent for Traffic Simulation with Vehicle Dynamic Model) were proposed. MATDYMO consists of the road management system, the vehicle motion control system, the driver management system, and the integration control system. Among these systems, the road management system and the integration control system were discussed In the companion paper. In this paper, the vehicle motion control system and the driver management system are discussed. The driver management system constructs the driver agent capable of having different driving styles ranging from slow and careful driving to fast and aggressive driving through the yielding index and passing index. According to these indices, the agents pass or yield their lane for other vehicles; the driver management system constructs the vehicle agents capable of representing the physical vehicle itself. A vehicle agent shows its behavior according to its dynamic characteristics. The vehicle agent contains the nonlinear subcomponents of engine, torque converter, automatic transmission, and wheels. The simulation is conducted for an interrupted flow model and its results are verified by comparison with the results from a commercial software, TRANSYT-7F. The interrupted flow model simulation is implemented for three cases. The first case analyzes the agents' behaviors in the interrupted flow model and it confirms that the agent's behavior could characterize the diversity of human behavior and vehicle well through every rule and communication frameworks. The second case analyzes the traffic signals changed at different intervals and as the acceleration rate changed. The third case analyzes the effects of the traffic signals and traffic volume. The results of these analyses showed that the change of the traffic state was closely related with the vehicle acceleration rate, traffic volume, and the traffic signal interval between intersections. These simulations confirmed that MATDYMO can represent the real traffic condition of the interrupted flow model. At the current stage of development, MATDYMO shows great promise and has significant implications on future traffic state forecasting research.

• Journal of the Korea Safety Management & Science
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• v.13 no.1
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• pp.127-131
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• 2011

Even if there are no causing factors such as car crash and road works, traffic congestion come from traffic growth on the road. In this case, estimation of traffic flow helps find the solution of traffic congestion problem. In this paper, we present a optimization model which used on traffic equilibrium problem and studied the problem of inverting shortest path sets for complex traffic system. And we also develop pivotal decomposition algorithm for reliability function of complex traffic system. Several examples are illustrated.

• Journal of Advanced Navigation Technology
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• v.28 no.4
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• pp.436-441
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• 2024

Urban air mobility (UAM) is an innovative air traffic management system that utilizes electric vertical take off and landing aircraft(eVTOL) to transport passengers and cargo in urban areas. The corridor can be defined as the airspace that the vehicle operates in and must be collaboratively managed. For the stable operation of UAM, it is essential to have strategic separation and a collaborative decision-making(CDM) system for cooperation and coordination among stakeholders. This study examines the application of time-based milestones from traditional air traffic flow management to the UAM system to ensure safe traffic volume and optimize air traffic flow. For traffic flow management, the milestone time information is categorized into a total of 13 key milestone time indicators based on the UAM movement status, and the sharing entities providing each time indicator and the flow of milestones are defined. Emphasizing the need for a CDM to balance UAM traffic and capacity, sharing and managing milestone information among stakeholders is expected to improve UAM aircraft departure flow and enhance operational efficiency.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1359-1363
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• 2009

The object of this research is to develop a simulation system for earthmoving operations in consideration of the impact of congestion in-between equipment and existing traffic flow around the site. The congestion in-between equipment and traffic flow affect work productivity. The conventional discrete event simulation, however, has limitations in simulating the flow of construction equipment. To consider the impact of congestion in-between equipment and existing traffic flow, in this paper, a multi-agent based simulation model that can realize characteristics of truck behavior more accurately to consider the impact of congestion was proposed. In this simulation model, multiple agents can identify environmental changes and adapt themselves to the new environment. This modeling approach is a better choice for this problem since it describes behavioral characteristics of each agent by sensing changes in dynamic surroundings. This study suggests a detailed system design of the multi-agent based simulation system.

• Journal of Korean Society of Transportation
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• v.28 no.4
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• pp.167-175
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• 2010

The ubiquitous transportation system environments make it possible to collect each vehicle's position and velocity data and to perform more sophisticated traffic flow management at the individual vehicle or platoon level through vehicle to vehicle (V2V) and vehicle to infrastructure (V2I) communication. It is necessary to develop a traffic flow management scheme to take advantage of the ubiquitous transportation system environments. This paper proposes an algorithm to advise the optimal speed for each vehicle according to the traffic flow condition. The algorithm aims to stabilize the traffic flow by advising the equilibrium speed to the vehicles speeding or crawling under freely flowing condition. And it aims to prevent or at least alleviate the shockwave propagation by advising the optimal speed that should dampen the speed drop under critical flow conditions. This paper builds a simulation testbed and performs some simulation experiments for the proposed algorithm. The proposed algorithm shows the expected results in terms of travel time reduction and congestion alleviation.

• Proceedings of the Korean Society of Computer Information Conference
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• 2017.07a
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• pp.322-323
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• 2017

본 논문은 대규모 트래픽을 처리하는 NFV환경의 서비스 기능 체이닝 영역에서 sFlow 기반의 트래픽 분류기를 이용한 트래픽 관리 기법을 제안하고 있다. sFlow의 실시간 트래픽 샘플링을 사용하여 실시간으로 변화하는 트래픽의 효과적인 관리를 기대할 수 있으며, 제안한 트래픽 관리 기법은 대규모 트래픽의 네트워크 안정성과 보안을 향상시킨다.