• Journal of Korean Society of Transportation
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• v.27 no.1
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• pp.143-155
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• 2009

A dynamic traffic assignment (DTA) has recently been implemented in many practical projects. The core of dynamic model is the inclusion of time scale. If excluding the time dimension from a DTA model, the framework of a DTA model is similar to that of static model. Similar to static model, with given exogenous travel demand, a DTA model loads vehicles on the network and finds an optimal solution satisfying a pre-defined route choice rule. In most DTA models, the departure pattern of given travel demand is predefined and assumed as a fixed pattern, although the departure pattern of driver is changeable depending on a network traffic condition. Especially, for morning peak commute where most drivers have their preferred arrival time, the departure time, therefore, should be modeled as an endogenous variable. In this paper, the authors point out some shortcomings of current DTA model and propose an alternative approach which could overcome the shortcomings of current DTA model. The authors substitute a traditional definition for time-dependent OD table by a new definition in which the time-dependent OD table is defined as arrival time-based one. In addition, the authors develop a new DTA model which is capable of finding an equilibrium departure pattern without the use of schedule delay functions. Three types of objective function for a new DTA framework are proposed, and the solution algorithms for the three objective functions are also explained.

• Journal of Navigation and Port Research
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• v.30 no.10 s.116
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• pp.819-823
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• 2006

Since the north port in Busan started to operate in general pier (1, 2, central, 3 and 4), the business area had been expanded to Jasungdae, Shinsundae, Gamman zone and so on However, these zones adjoin the Busan city and have caused problems to both logistics and city activities. The operation of Off-Dock Container Yard (ODCY) is a representative example due to the limited sphere of Container Yard in this city. It increases logistics costs and causes serious social problems as a result of increasing traffic in the trunk roads such as Uam and Chungjang roads. This paper aims to analyze the effects of the reduction in traffic of trunk roads in Chungjan, Uam roads and so on, when General Pier and Jasungdae Pier are Re-developed. The effects of the reduction in social cost from traffic congestion are also analyzed. Finally, we predict and evaluate the effects according to the re-development of two piers, north pier and Jasungdae pier.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.275-279
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• 2006

Since the North port in Busan started to operate in general pier (1, 2, central, 3 and 4), the business area had been expanded to Jasungdae, Shinsundae, Gamman zone and so on. However, these zones adjoin the Busan city and have caused problems to both logistics and city activities. The operation of Off-Dock Container Yard (ODCY) is a good representative example due to the limited sphere of Container Yard in this city. It increases logistics costs and causes serious social problems as a result of increasing traffic in the truck roads such as Uam and Chungjang roads. This paper aims to analyze the effects of the reduction in traffic of trunk roads in Chungjan, Uam roads and so on, when General Pier and Jasungdae Pier are Re-developed. The effects of the reduction in social cost from traffic congestion are also analyzed. Finally, we predict and evaluate the effects according to the re-development of two piers, north pier and Jasungdae pier.

• Journal of Korean Society of Transportation
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• v.22 no.4 s.75
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• pp.107-116
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• 2004

VMS를 통한 정보제공에는 과도반응과 통행집중의 위험부담이 따른다. 즉 대안경로간에 이루어져야 할 통행배분을 정확히 유도할 수 있는 VMS 메시지란 존재치 않는다. VMS 메시지에 의해 특정 경로가 교통상황이 타 경로에 비해 좋다고 정보가 주어질 때, 그 정보에 대한 과도반응과 그 특정경로에 대한 통행집중 문제가 발생하여 정보제공에 의해 오히려 상황이 악화될 수 있다. 본 연구에서는 대안경로간의 물리적 특성 측면에서 우열이 있는 가상 네트워크를 대상으로 하여, 과도반응과 통행집중 문제를 극복하고 대안경로간의 적절한 통행배분을 달성하기 위한 VMS 운영알고리즘을 개발하는 것을 목표로 한다. VMS정보제공 결과, 즉 VMS를 통해 상황이 좋다고 알려준 경로에 통행이 집중할 경우 문제가 될 것인가 여부를 미리 예측해 보고, 문제가 될 경우 정보제공 전략을 수정하도록 하는, 피드백 제어에 예측적 방식을 접목하였다. 본 연구에서 제안한 알고리즘의 주요 기능은 다음과 같다. 1. 교통량, 속도 등에 대한 실시간 모니터링 시스템이 구축되어 있음을 전제로 한다. 2. 실시간 제어에는 모니터링 결과와 이에 근거한 정보제공전략의 시행사이에는 시간차가 존재한다. 이러한 시간차이로 인하여 단기예측이 필요하고, 이를 수행하는 모듈이 있다. 3. 정보제공 결과로 특정 경로에 과부하가 걸리는지 여부를 예측하기 위하여, 그 판단기준으로 그 경로의 실제 용량 산정이 필요하다. 이에 혼잡의 시공간적 전개에 따라 변하는 동적 용량을 산정하는 모듈이 있다. 4. 대안 경로간 통행배분 목표치를 수리적으로 산정할 수는 있으나, 이를 자동적으로 이루어 주는 메시지는 존재하지 않는다. 아울러 현실적으로 예측 불가능한 외란을 모형에 의존하여 예측하기 보다는, 계속적인 피드백 레귤레이터(Regulator) 작동에 의해 보정하여 목표를 달성해 가는 자동제어 기능을 갖고 있다.

• The Journal of Bigdata
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• v.5 no.2
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• pp.85-95
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• 2020

In this study, a mobility analysis method is suggested to estimate an O/D trip demand estimation using Mobile Phone Signaling Data. Using mobile data based on mobile base station location information, a trip chain database was established for each person and daily traffic patterns were analyzed. In addition, a new algorithm was developed to determine the traffic characteristics of their mobilities. To correct the ping pong handover problem of communication data itself, the methodology was developed and the criteria for stay time was set to distinguish pass by between stay within the influence area. The big-data based method is applied to analyze the mobility pattern in inter-regional trip and intra-regional trip in both of an urban area and a rural city. When comparing it with the results with traditional methods, it seems that the new methodology has a possibility to be applied to the national survey projects in the future.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.3 no.1 s.4
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• pp.31-44
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• 2004

The study of Estimation model for the short-term travel time prediction. There is a different solution which has predicted the link travel time to solve this problem. By using this solution, the link travel time is predicted based on link conditions from time to time. The predicated link travel time is used to search the shortest path. Before providing a dynamic shortest path finding, the prediction model should be verified. To verify the prediction model, three models such as Kalman filtering, Stochastic Process, ARIMA. The ARIMA model should adjust optimal parameters according to the traffic conditions. It requires a frequent adjustment process of finding optimal parameters. As a result of these characteristics, It is difficult to use the ARIMA model as a prediction. Kalman Filtering model has a distinguished prediction capability. It is due to the modification of travel time predictive errors in the gaining matrix. As a result of these characteristics, the Kalman Filtering model is likely to have a non-accumulative errors in prediction. Stochastic Process model uses the historical patterns of travel time conditions on links. It if favorably comparable with the other models in the sense of the recurrent travel time condition prediction. As a result, for the travel time estimation, Kalman filtering model is the better estimation model for the short-term estimation, stochastic process is the better for the long-term estimation.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.1
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• pp.101-116
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• 2017

This Study estimates the actual night traffic using the smart card data used by most of the public transportation users, and compares it with the current night bus routes by KT Telecom based on the night time call volume. In order to compare the current night bus and night trips evaluated by smart card data, we presented indicators related to the degree of matching, and estimated the volume of service currently provided. The unique approach of the study is that we chose subway station instead of bus stop for the unit of the study. Bus stops has their complexity in a way that stops with same name could belong to different administrative area depending on its direction. For this reason, we decided to use subway station and defined its adjacent administrative district as the scope of influence. Since night bus is the primary means of transportation during the late night, it is anticipated that they will be able to provide better service by calculating the actual traffic and selecting the routes.

• Journal of Korean Society of Transportation
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• v.16 no.3
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• pp.37-45
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• 1998

교통영향평가는 1985년 서울시에서 실시된 이후 사업 시행자에 의해 개발지 주변 도로 교통상황을 개선하는데 크게 기여하여 왔으며 향후 이러한 교통유발 원인자 부담원칙 에 의한 교통개선체제는 지방 자치화 시대를 맞이하여 계속 유지될 전망이다. 하지만 교통 영향 평가시 도로개선의 판단 기중이 되는 개발에 따른 교통발생 예측량이 평가자에 따라 상이한 결과가 나타나고 이에 따른 상이한 주변 도로 서비스수준(LOS)이 도출되어 합리적 교통처리 방안 제시에 문제가 되고 있다. 이러한 문제는 광역적 교통량 예측 프로그램 이 용, 상이한 통행 발생원단위 사용, 그리고 일률적 교통량 예측범위에 기인한다. 따라서 본 연구는 교통영향 평가시 국내와 미국의 교통량 예측 방법 비교·분석을 통해 합리적 교통량 예측방법을 제시하였다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.719-727
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• 2013

Four-step travel-demand modeling based on a trip-level has been widely used over many decades. However, there has been a wide variance between forecasted- and real-travel demands, which leads less reliable on the model implications. A primary reason is that person's real travel behavior is not properly captured throughout the model developments. An activity-based modeling (ABM) approach was proposed and developed toward increasing the accuracy and reality of person's travel behavior in the U.S. since 1990', and stands as a good alternative to replace the existing trip-based approach. The paper contributes to the understanding of how the ABM approaches are dissimilar to the trip-based modeling approach in terms of estimation units, estimation process, their pros and cons and etc. We examined three activity-based travel demand model systems (DaySim, CT-Ramp, and CEMDAP) that are most commonly applied by many MPOs (Metropolitan Planning Organization). We found that the ABM approach can effectively explain multi-dimensional travel decision-makings and be expected to increase the predictive accuracy. Overall, the ABM approach can be a good substitute for the existing travel-demand methods having unreliable forecasts.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.3
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• pp.51-61
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• 2023

Travel demand estimation of E-Scooter is the start point of solving the regional demand-supply imbalance problem and plays pivotal role in a linked transportation system such as Mobility-as-a-Service (a.k.a. MaaS). Most focuses on developing trip generation model of shared E-Scooter but it is no study on selection of an appropriate zone scale when it comes to estimating travel demand of E-Scooter. This paper aimed for selecting an optimal TAZ scale for developing trip distribution model for shared E-Scooter. The TAZ scale candidates were selected in 250m, 500m, 750m, 1,000m square grid. The shared E-Scooter usage historical data were utilized for calculating trip distance and time, and then applying to developing gravity model. Mean Squared Error (MSE) is applied for the verification step to select the best suitable gravity model by TAZ scale. As a result, 250m of TAZ scale is the best for describing practical trip distribution of shared E-Scooter among the candidates.