• Journal of Korean Society of Transportation
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• v.34 no.6
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• pp.499-509
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• 2016

The pedestrian traffic flow has more complicated microscopic features than vehicular traffic flow. Without any designated lanes or any guidance, pedestrians naturally move and change their routes in two dimensional domain with ease. Thus the assessment of pedestrian comfort level should be considering the microscopic features of pedestrian flow. This study is aimed at developing pedestrian comfort criteria based upon pedestrian flow simulation model. This study suggests three criteria to determine pedestrian comfort level; the deviation of route, the acceleration of walk, and the number of collision. Each criterion, which can address the unique walking patterns of pedestrian flow, is represented as each different function with respect to traffic flow rate. The criteria can be the additional indicators to determine the level of service of pedestrian flow together with traffic flow rate and walking speed.

• Journal of Korean Society of Transportation
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• v.24 no.3 s.89
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• pp.39-50
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• 2006

This study aims to introduce a basic principle to improve the incident detection algorithm using traffic flow diagrams that can classify traffic states with a high reliability on the basis of the analysis of traffic flow characteristics under the recurrent or incident congestions. It is tried to newly classify the traffic states with the speed-flow and speed-occupancy diagrams. This is because McMaster algorithm has a tendancy on not identifying the traffic states exactly using the flow-occupancy diagram. In this study it shows that the classification of traffic states is applicable to use speed-occupancy relationship Therefore, it is necessary to determine some parameters to correctly classify the areas representing the traffic states and it may be possible to develop a new algorithm to detect the incident with a high reliability.

• Journal of Korean Society of Transportation
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• v.20 no.5
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• pp.67-79
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• 2002

In this paper, observed trajectories of a vehicle platoon are viewed as one realization of a finite sequence of random trajectories. In this point of view, we develop novel and mathematically rigorous concept of traffic flow variables such as local traffic density, instantaneous traffic flow, and velocity field and investigate their nature on a general probability space of a sequence of random trajectories which represent vehicle trajectories. We present a simple model of random trajectories as an illustrative example and, derive the values of traffic flow variables based on the new definitions in this model. In particular, we construct the model for the sequence of random vehicle trajectories with a system of stochastic differential equations. Each equation of the system nay represent microscopic random maneuvering behavior of each vehicle with properly designed drift coefficient functions and diffusion coefficient functions. The system of stochastic differential equations nay generate a well-defined probability space of a sequence of random vehicle trajectories. We derive the partial differential equation for the expected cumulative plot with appropriate initial conditions. By solving the equation with numerical methods, we obtain the values of expected cumulative plot, local traffic density, and instantaneous traffic flow. In addition, we derive the partial differential equation for the expected travel time to a certain location with appropriate initial and/or boundary conditions, which is solvable numerically. We apply this model to a case of single vehicle trajectory.

• Journal of Korean Society of Transportation
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• v.29 no.4
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• pp.17-28
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• 2011

This study proposed a speed management strategy for the enhancement of traffic safety on freeways. A novel feature of the proposed strategy is to provide desirable speed information to individual vehicles. A microscopic traffic simulator, VISSIM, was used for the performance evaluation. Vehicle trajectory data were used to evaluate the various speed management scenarios including the different levels of proportions of heavy vehicles. The proposed speed management strategy would be a useful precursor for developing an effective traffic control and operations system to prevent traffic accidents on freeways.

• Journal of Korean Society of Transportation
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• v.25 no.2 s.95
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• pp.73-81
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• 2007

The purpose of this paper is to perform a basic study on the interaction between lanes, which can be achieved through analyzing traffic breakdown at the microscopic level. Using aerial photographic data for the microscopic analysis, this study analyzed the characteristics of traffic flow at a merging area. This research produced aggregated traffic data such as flows, speeds, and densities in 30 second intervals by lane for the macroscopic analysis and individual headway data by lane for the microscopic analysis. The paper contains an analysis of lane characteristics through flows, speeds, densities, and headway variations and also investigates the influence of ramp flows on mainline flows with space-time diagrams. Firstly, the merging area in this study is divided into three sections: before-merging, during-merging, and after-merging. The transition process was analyzed at each lane. Secondly, the breakdown was observed in detail with data divided in 50-foot units. The breakdown was checked through the relationships between ramp and freeway mainline flows, various techniques were proposed to analyze the breakdown, and the formation of breakdown was introduced as three stages in this study. In the near future, the findings of this study could contribute to determining the dynamic capacity on freeways by easily understanding changeable traffic breakdown patterns over time and space.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.11a
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• pp.275-277
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• 2018

선박 및 해상교통관제에 있어서 교통 혼잡구역에 대한 선박교통밀도 예측은 선박충돌사고 예방에 중요하다. 선박 교통밀도 예측정보는 사전에 진입하는 선박들에게 속력조정, 우회항로 이용 등 사전 조치가 가능하다. 본 연구에서는 해상 선박교통상황을 딥러닝 네트워크에 학습한 주의구역 선박교통류 예측 모델(Ship Traffic Extraction Network, STENet)을 제안하여 주의구역의 선박교통류 예측을 수행하고자 한다. STENet 모델 학습을 위해 여수해역 AIS 데이터를 전처리하고, 생성된 입력(해상교통상황)-출력(주의구역 교통밀도) 쌍 데이터를 적용하여 STENet 모델을 학습하였다. 학습된 모델을 이용하여 선박교통류 예측을 한 결과, 중기예측은 표준 절대 오차(mean absolute error)가 0.4-0.5척이 였으며, 장기예측은 0.7-0.8척의 오차로 기존의 Dead Reckoning에 의한 방법보다 50% 이상 교통밀도 예측성능이 향상 되었다.

• Journal of Korean Society of Transportation
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• v.20 no.2
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• pp.93-104
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• 2002

The purpose of this study was to develop a improved high-order continuum model among macroscopic traffic flow models. This study was mainly performed for uninterrupted flow. In the first step, the proposed model described traffic flow at dropped lane. (no exits) It was possible to describe the traffic flow during short-term considering lane change. The proposed model was based on Payne's model. Our model was newly applied to uninterrupted traffic flow in consideration of geometry condition and driver behavior. It is possible to establish efficient control strategies, simulation and assess the effects of geometric improvements using this model. This model was simulated with field data for the actual adaption. The results of the model tests, traffic volume and density is suitably represented. we think that the results in the article can be led to predicting the situation in the near future.

• Journal of Korean Society of Transportation
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• v.19 no.2
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• pp.107-107
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• 2001

• Proceedings of the KOR-KST Conference
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• 1998.10b
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• pp.295-295
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• 1998

고속도로에서 교통류의 특성에 파악하여 교통류의 특성을 파악하여 동적행태로 교통상황을 분석하고 효과적인 제어전략, 시뮬레이션, 그리고 기하구조 개선등의 효율적이고 실용적인 적용을 위해서는 교통류의 정확한 모사가 필요하다. 시공간으로 표현되는 상태방정식을 포함하는 거시적 시뮬레이션 모델에 사용되는 연속류 모델은 이러한 교통류 특성을 모사하는데 적절하다. Lighthill과 Whitham(1955), Richard(1956)에 의해 일계도함수의 형태를 가지는 단순모델이 제시된 이후 모델의 결점을 보완하기 위해 많은 고계도 모델이 제시되었지만 고계도 모델이 가진 이론적인 결점에 대해서는 여러 연구들이 제시되어 있다. 또한 고계도 모델은 운동량 방정식의 유도, 정산, 구현의 어려움으로 널리 사용되기 힘들다는 단점을 가지고 있다. 만일 적절히 구현할 수 있다면 적용이 간단한 단순모델로도 보다 정확한 교통류 상황 모사가 가능하다. Ansorge는 혼잡교통류상황을 보다 정확하게 모사하기 위해 단순모델에 엔트로피 조건을 결합시킨 모델을 제시했다. Bui는 이 제안된 모델이 적절한 시뮬레이션 결과를 나타낸다는 것을 밝혔다. 그러나 이 모델은 차량의 재가속이 이루어지는 교통상황-stop-start wave의 경우 비현실적인 값을 가진다. 엔트로피조건에 의해 구해진 해는 실제보다 과다한 교통량을 추정하게 되는데 이런 결과는 위와 같은 교통상황에서 중요한 요소로 작용하는 가속효과가 무시되고 있기 때문이다. 따라서 본 연구에서는 stop-start wave 조건에서 가속도에 경계치를 부여하여 교통류율을 상한경계조건을 제시함으로써 교통상황에 맞는 교통류율을 산정하는 방법에 대해 제안하고자 한다.환승이라는 특정대안변수(Specific alternative variable)를 첨가하여 그것이 수단선택에 미치는 영향을 분석한다. 또한, 대중교통의 속성을 가지고 있는 지하철과 버스를 하나의 대안으로 묶어서 효용함수를 구한 다음 다시 승용차, 택시, 대중교통을 독립된 대안으로 두고 모형을 정립하는 NESTED LOGIT모형으로 파라메타를 추정하여 대중교통의 효용에 관해 분석·비교하였다. 본 논문에 이용된 자료는 공항을 이용하는 이용객들을 대상으로 직접 설문·면접조사한 자료이며 대상 교통수단은 승용차, 택시, 지하철, 버스로 설정하였다. 결과 적응형 알고리즘이 개개인의 최단시간 경로를 제공하는 사용자 평형 경로안내전략에 비해 교통혼잡도와 정체시간의 체류정도에 따라 3%에서 10%까지 전체통행시간을 절약할 수 있다는 결론을 얻었다.출발참, 구성대외개방선면축심, 실현국제항선적함접화국내항반적전항, 형성다축심복사식항선망; 가강기장건설, 개피포동제이국제기장건설, 괄응포동개발경제발전적수요. 부화개시일은 각 5월 26일과 5월 22일이었다. 11. 6월 중순에 애벌레를 대상으로 처리한 Phenthoate EC가 96.38%의 방제가로 약효가 가장 우수하였고 3월중순 및 4월중순 월동후 암컷을 대상으로 처리한 Machine oil, Phenthoate EC 및 Trichlorfon WP는 비교적 약효가 낮았다.>$^{\circ}$E/$\leq$30$^{\circ}$NW 단열군이 연구지역 내에서 지하수 유동성이 가장 높은 단열군으로 추정된다. 이러한 사실은 3개 시추공을 대상으로 실시한 시추공 내 물리검층과 정압주입시험에서도 확인된다.. It was result

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.6
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• pp.47-54
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• 2021

The number of freeway traffic accidents in Korea is about 4,000 as of 2020, and deaths per traffic accident is about 3.7 times higher than other roads due to non-recurring congestion and high driving speed. Most of the accident types on freeways are side and rear-end collisions, and one of the main factors is hazard traffic flow caused by merge, diverge and accidents. Therefore, the hazard traffic flow, which appears in a continuous flow such as a freeway, can be said to be important information for the driver to prevent accidents. This study tried to classify hazard traffic flows, such as the speed change point and the section where the speed difference by lane, using individual vehicle information. The homogeneous segment of speed was classified using spatial separation based on geohash and space mean speed that can indicate the speed difference of individual vehicles within the same section and the speed deviation between vehicles. As a result, I could extract the diverging influence segment and the hazard traffic flow segment that can provide dangerous segments information of freeways.