• Journal of Korean Society of Transportation
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• v.22 no.3 s.74
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• pp.159-166
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• 2004

The capacity concept presented in the Highway Capacity Manual is for steady-state traffic flow assuming that there is no restriction in downstream flowing, which is traditionally used for planning, design, and operational analyses. In the congested traffic condition, the control objective should be to keep the congested regime from growing and to recover the normal traffic condition as soon as possible. In this control case, it is important to predict the spatial-temporal pattern of congestion evolution or dissipation and to estimate the throughput reduction according to the spatial-temporal pattern. In this context, the new concept of dynamic capacity for managing congested traffic is developed in terms of spatial-temporal evolution of downstream traffic congestion and in view of the 'input' concept assuming that flow is restricted by downstream condition rather than the 'output' concept assuming that there is no restriction in downstream flowing (e.g. the mean queue discharge flow rate). This new capacity is defined as the Maximum Sustainable Throughput that is determined based on the spatial-temporal evolution pattern of downstream congestion. And the spatial-temporal evolution pattern is estimated using the Newell's simplified q-k model.

• Journal of Korean Society of Transportation
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• v.17 no.2
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• pp.179-191
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• 1999

To device effective freeway traffic flow control strategies and freeway traffic information dissemination strategies, it is very important to estimate real physical queue length on the freeway. Shock wave theory and queueing theory have limitation to be used to estimate the queue length. The primary objective of this study is to develop a reliable method for estimating the physical queue length and level of congestion. Queueing propagation processes were analysed by using such traffic data as main line traffic volume, ramp volume, density. speed, and physical queue length collected by video photographing on Olympic Freeway. As a result of analysis, it has been confirmed that the real queue length can be estimated by using the traffic counts arriving the congested region and passing a bottleneck location. Further more, a reliable method for estimating the level of congestion could be developed on the basis of real-time traffic counts.

• The Journal of the Korea Contents Association
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• v.18 no.11
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• pp.643-654
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• 2018

In order to understand and manage traffic flows in urban areas in the past, a variety of traffic engineering theoretical indicators such as intersection lag and highway speed have been applied. However, these theories and indicators have been developed under the constraints of traffic engineering research before the construction of intelligent transportation system. Since the ATIS system currently exists, it is necessary to introduce a separate traffic engineering technology that utilizes the data. In this paper, it is aimed to confirm whether it is applicable to intermittent flow (approach road, intersection, control group, main road axis) by using 'congestion intensity' which is already used in traffic engineering field. The results of this study are as follows: (1) The traffic signal improvement effect of urban road access road, intersection road, control group, Two verification studies were performed to verify the derived congestion intensity index. (1) verification of congestion intensity threshold value analysis and (2) crossing improvement using the congestion intensity. Through verification, it was confirmed that it is possible to apply the congestion intensity in the inter - city intermittent flow using the 5 - minute unit speed data so as to be able to escape from the existing traffic signal operation management which is past passive and manpower limit.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1811-1825
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• 2011

This study analyzed the transit services with respect to transit service measures such as the load factor representing number of passengers between stops, dwelling time, and operational speed based on transit smart card data recorded in 2009. A case study on the local bus line 7024 connecting Seoul railway station to evaluate bus services at passenger perspectives was accomplished. From the results, we found that the dwelling time was not affected by the number of passengers which is because the tagging patterns are different among passengers. The operational speed was analyzed by calculating the average speed of the bus route and the speed of each bus stops based on dwelling time. Interestingly, calculating operation speed based on the transit smart card data is the first time effort ever made and this means that it is not necessary to observe travel speed of bus and railway at a field level any more. we hope that this study will be a basis of evaluation of transit services purely based on the transit smart card data and help to make better transit services for passengers and operators as well.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.2
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• pp.1-11
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• 2013

This research proposed integrated expressway traffic management strategy using ramp metering and toll mainline metering. This research suggested a traffic signal optimization model for integrated operation of ramp and mainline metering based on Demand-Capacity Model that is used to optimize allowable input volume for ramp metering in FREQ model. The objective function of this model is sectional throughput volume maximization, and this model can calculate optimal signal timings for mainline metering and ramp metering. This study conducted an effectiveness analysis of integrated metering strategy using PARAMICS and its API. It targeted Seoul's Outer Ring Expressway between Gimpo and Siheung toll gate. As a simulation result, integrated operation of mainline and ramp metering provided more smooth traffic flow, and throughput volume of mainline increased to 14% in congested section. In addition, a queue of 400 meter was formed at metering point of toll gate. This research checked that integrated traffic management strategy facilitates more efficient traffic operation of mainline and ramp from diffused traffic congestion.

• Journal of Korean Society of Transportation
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• v.20 no.3
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• pp.69-82
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• 2002

The objective of this study is to evaluate the performance of macroscopic traffic flow models with the analytical and field data. Five candidate models were selected as follows ; Lax Method Model, Upwind Scheme Model, Hilliges'Model, Papageorgiou's Model, and Cell-Transmission Model. In the analytical test scenario, the traffic condition was assumed that could cause the building and dissipation of queue, and each model was compared with analytical solutions and the numerical results. An analytical test indicated that both simple continuum and high order continuum models are able to reproduce queue building and dissipating behavior in a reasonable way A field test has shown that Upwind and Papageorgiou's model show similar performances. Considering the simplicity in model formulation and numerical computation, we firstly recommend Upwind scheme model , and secondly Papageorgiou's model that performed will to represent traffic flow in tests as candidate models for further development of simulation model for Naebu expressway in Seoul.

• International Journal of Highway Engineering
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• v.11 no.1
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• pp.145-151
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• 2009

Current highway design standards is based on the safety under the free flow condition. The length of deceleration lane is also determined in terms of the deceleration distance which is necessary for the driers to adjust the vehicle speed from the speed limit on the main road to that on the exit ramp of the interchange. However, the queues are frequently developed on the deceleration, and the following vehicles to exit must decelerate on the main road. It may cause delay on the main road and traffic accidents. This study is to suggest a methodology to minimize such problems with the shock-wave theory. The queue length of exiting vehicles can be estimated by the design speeds, traffic volumes of main road and the exiting ramp, and the countermeasures to the operational problems. According to the results, the queue length can be shortened to 80% by upgrading the design speed of exit ramp as the amount of 10km/h. Fifty percent of queue length can be shortened by adding an additional lane on the ramp to two lanes.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.10a
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• pp.240-242
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• 2012

2011년 6월 '해상교통안전법'이 '해사안전법'으로 전부 개정된 후 진단시행지침의 전부 개정을 통해 선박안전기술공단 해사안전연구센터가 진단전문기관으로 지정되었다. 하지만 국가업무를 대행 또는 위탁하는 형식이 아닌 진단서에 대한 의견을 제시하는 수준으로 전문기관의 설립 및 역할이 불명확하여 정부의 예산지원이나 수수료 등의 징수 근거로 한계가 있는 것으로 조사되었다. 따라서 본 연구에서는 도로교통안전진단, 시설물안전진단, 환경영향평가 등 유사제도의 전문기관 운영현황을 분석한 결과, 법에서 전문기관의 존재 및 역할을 명확히 규정하여 정부의 예산지원이나 수수료 등 징수근거가 명확한 상태에서 전문기관의 역할을 수행하고 있으며, 담당 공무원의 업무 연속성 및 전문성 부재로 제도의 효율적 운영을 위해서는 전문기관의 역할 및 권한 확대와 더불어 진단기술관련 역량 강화를 통해 전문성 향상이 필요한 것으로 조사되었다. 향후과제로 안정적인 전문기관의 역할 수행을 위해 관련법령을 정비하여 전문기관의 설립 및 업무 위탁을 명확히 규정할 필요가 있다.

• Journal of Korean Society of Transportation
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• v.23 no.6 s.84
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• pp.55-67
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• 2005

There are 24 airways in Incehon IFR, including 11 domestic routes and 13 international routes. The airways designated by ministry of Transportation and Construction are the routes for aircraft to fly being serviced by air traffic control system for flight safety. This study reviewed safety situation of existing permanent airways within Incheon IFR and temporary airways connecting North and South Korea. The study tried to identify the problems related to airway operation and to suggest solutions to the questionable area. The main findings are as follows: It is necessary to improve the existing normal airway systems and enlargement of the route. The airway A593 has to be upgraded to normal route. The temporary airways established to connect Seoul and Pyongyang also needs to be upgraded by air traffic control transfer agreement between two Koreas.

• Journal of Korean Society of Transportation
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• v.20 no.6
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• pp.17-30
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• 2002

부산항은 컨테이너터미널 운영사별로 마케팅 전략 수립 및 마케팅 활동이 개별적으로 이루어질 뿐 항만 관련 유관기관(부산시, 부산지방해양수산청, 한국컨테이너부두공단, 부산본부세관)의 조화된 항만 마케팅 전략 및 역할이 수립되지 않은 상태이다. 따라서 본 연구에서는 부산항 활성화를 위한 각 주체별 활동 현황을 조사하고, 항만 이용자인 선사 및 포워더를 대상으로 마케팅 믹스(Mix, 4P: Product, Place, Price, Promotion)에 대한 설문조사를 토대로 부산항 마케팅 분석을 실시한다 이를 바탕으로 부산항이 동북아 중심항만으로 성장하는데 필요로 하는 부산항 관련 각 주체별 마케팅 관계 그리고 역할을 제시한다. IPA(Importance-Performance Analysis) 분석 결과를 살펴보면 전체 고객을 대상으로 평가했을 때 가격 믹스와 촉진믹스는 가장 중요도가 높은 것으로 분석되었으며 특히, 촉진믹스는 중요도는 매우 높으나 만족도가 낮은 것으로 분석되었다. 그러므로 마케팅 전략 수립 시 촉진 부문에도 높은 비중을 두어 선사들에게 공격적인 마케팅 활동이 요구된다고 할 수 있다. 부산항 관련 각 주체별 마케팅 역할에서 부산광역시는 부산지방해양수산청과 함께 촉진믹스에 중점을 두어야하고, 부산지방해양수산청은 촉진믹스 외에 가격믹스에서 항만 요율의 적절성과 경로믹스인 철도 수송 망의 확보가 시급한 것으로 나타났다. 한국컨테이너부두공단은 촉진믹스 외에 가격믹스에서 항만시설 사용료의 체계적인 개편이 요구되고, 터미널 운영사는 제품믹스 서비스인 공컨테이너의 효율적인 재고관리 업무서비스와 가격믹스에서 하역요율의 탄력적인 제공이 필요하다.