• 한국도로학회논문집
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• 제16권5호
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• pp.99-108
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• 2014

PURPOSES : The travel times of expressway buses have been estimated using the travel time data between entrance tollgates and exit tollgates, which are produced by the Toll Collections System (TCS). However, the travel time data from TCS has a few critical problems. For example, the travel time data include the travel times of trucks as well as those of buses. Therefore, the travel time estimation of expressway buses using TCS data may be implicitly and explicitly incorrect. The goal of this study is to improve the accuracy of the expressway bus travel time estimation using DSRC-based travel time by identifying the appropriate analysis period of input data. METHODS : All expressway buses are equipped with the Hi-Pass transponders so that the travel times of only expressway buses can be extracted now using DSRC. Thus, this study analyzed the operational characteristics as well as travel time patterns of the expressway buses operating between Seoul and Dajeon. And then, this study determined the most appropriate analysis period of input data for the expressway bus travel time estimation model in order to improve the accuracy of the model. RESULTS : As a result of feasibility analysis according to the analysis period, overall MAPE values were found to be similar. However, the MAPE values of the cases using similar volume patterns outperformed other cases. CONCLUSIONS : The best input period was that of the case which uses the travel time pattern of the days whose total expressway traffic volumes are similar to that of one day before the day during which the travel times of expressway buses must be estimated.

• 대한산업공학회지
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• 제23권4호
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• pp.621-633
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• 1997

This paper is concerned with the multiobjective vehicle scheduling problem with time and area-dependent travel speeds(MVSPTD), in which two conflicting objectives are explicitly treated and the travel speed between two locations depends on the passing area and time of day. The two objectives are the minimization of total vehicle travel time and the minimization of total weighted tardiness. First, I construct a mixed integer linear programming formulation of the MVSPTD, and present o heuristic algorithm that builds the vehicle schedules based on the savings computed. The results of computational experiments showed that the heuristic performs very well. Finally, I propose an expert system for vehicle scheduling in the MVSPTD. Its whole process is executed under VP-Expert expert system environment.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1998년도 창립기념 춘계학술대회 논문집
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• pp.160-171
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• 1998

Express subway system is one of the effective systems adapting to improve service level. Express trains make fewer passenger stop, using a double track or a bypass track, than local trains which served all stations, Express service has been very popular with passengers who travel uninterrupted between terminals, but is has generated some dissatisfaction among passengers who experience longer waiting time on stations. This study aims at proposing the methodology to analyze changes of travel pattern in subway system adapting the express service and to estimate the time saving effects resulting from the installation of the express system. This methodology is evaluated in the fifth line under an assumpt ion that express subway system are adapted. Based on the results of the case study, the following conclusions are made: First, express system reduce a total travel time of 13% or above. Second, shorter headway of express trains increases the time saving effects on subway system. although it requests more waiting time to local train passenger. Third, an installation of Express system to Seoul subway system can augment subway demand in seoul metropolitan area.

• 상하수도학회지
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• 제11권4호
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• pp.80-90
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• 1997

The ILLUDAS and SWMM models were applied to the developing area of Dongsucheon for comparisons of the total runoff, peak discharge and travel time. For this purpose, the present and future urbanization rates were assumed 70% and 90%, respectively. The runoff analysis of two models has been performed based on 10, 20, 30 and 50 return periods and Huff's 4 quantiles for time distribution pattern of design rainfalls. As results, the total runoff based on Huff's pattern had an decreasing order of 1, 4, 3 and 2 quantiles for both models. The SWMM model showed that there were 4.3% increasing of the total runoff, 4.9% increasing of peak discharge, and 6.6% decreasing of travel time. Similarly, for ILLUDAS model, there were 7.3% and 9.2% increasing of total runoff and peak discharge, respectively and 9.1% decreasing of travel time.

• 대한토목학회논문집
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• 제26권4D호
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• pp.559-564
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• 2006

본 연구에서는 교통정보 제공의 부정적 영향을 최소화하면서 VMS 통행시간 정보를 제공하기 위하여 민감도 분석을 이용하여 링크 통행시간의 변화에 따른 링크 통행량의 변화를 추정하여 총 통행시간이 최소로 될 수 있도록 도로 이용자의 통행패턴을 유도하기 위한 정보제공 전략을 제시하였다. 이러한 분석의 틀은 최근에는 게임이론으로 확장되어 생각되어지고 있다. 실험의 결과에서 제시된 통행시간 정보제공 알고리즘이 총 통행시간을 감소시킬 수 있고 시스템 최적에 근접한 통행패턴을 유도할 수 있음을 확인할 수 있었다. 또한 정보 제공시 어떠한 경로의 통행시간 정보를 제공하는가가 중요한 문제가 될 수 있음을 확인하였다.

• 품질경영학회지
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• 제17권2호
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• pp.142-148
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• 1989

In order to determine the level of service which minimizes the total of expected cost of service and the expected cost of waiting for that service, the important considerations are to evaluate the distance traveled to and from a service facility (D) and the expected number of mechanics in queueing system (L). The travel-time models are very useful when the servers must travel to the customer from the service facility. Thus, in this paper we studied on the determination of the optimal service level by the travel-time models. In order to decide the optimal service level, (D) has been introduced as a uniform distribution and (L) has been introduced as M/M/S model of queueing theory.

• 지구물리와물리탐사
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• 제13권4호
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• pp.330-335
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• 2010

시추공 주시 토모그래피에 의하여 도출된 속도 영상의 신뢰도 평가를 위하여 파선-속도격자의 결합도와 시스템 행렬의 역산 특성 분석에 대한 연구를 실시하였다. 분석 대상은 SIRT법에 의하여 도출된 속도 모델과 이를 도출한 초동 주시와 파선 정보이다. 파선-속도격자 결합도는 파선 밀도 즉 격자 당 투사 파선 수와 파선 선분들의 합으로 산출하였고, 도출된 속도모델의 분해능 및 불확실성에 대한 정보는 데이터 공간(초동주시)과 모델 공간(속도모델)을 관련짓는 시스템 행렬의 특이 값 분해로부터 도출하였다.

• 대한교통학회지
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• 제14권4호
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• pp.91-106
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• 1996

This paper deals with on the efficiency questions of the left-turn prohibit at an isolated intersection and a corridor with 5-phase signal system. Its objectives are three-fold ; (1) to analyze the efficiency of the left-turn prohibit with the use of an imaginary network, (2) to evaluate various factors under consideration in decision making on the left-turn prohibit, (3) to provide a framework for estimating and evaluating overall impacts of the left-turn prohibit in traffic network. the major findings using an imaginary network and computer packages such as MINUTP, TRANSYT-7F and STATGRAPH are followings. First, left-turn prohibit reduces cycle length by 33 seconds and delay time per vehicle by 36 seconds at an isolated intersection, and cycle length by 31 seconds and delay time per veicle by 43 seconds along a corridor. Second, total vehicle mile of travel and total travel time at an isolated intersection seem up to increase 38.85 miles(57.36km), 14.4 hour on the average, Regarding to a corridor, total vehicle mile of travel is increased by 50.14 miles(80.22km), but total travel time is decreased by129.9 hours. Third, the efficiency of left-turn prohibit are affected the following eight factors including left-turn volume(veh/hr) and ratio(%), average delay time per vehicle(sec/veh) and others. Finally, several simple and multiple regression models to evaluate the impacts on the left-turn prohibit are formulated from the above eight factors. It can be expected that these models will take an important role in decision-making of left-turn prohibit.

• 정보통신설비학회논문지
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• 제8권3호
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• pp.122-131
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• 2009

Ubiquitous-Transportation sensor network is able to realize a vehicle ad-hoc network. Since there are some problems in an existing ITS system, the new technology and traffic information strategies are requirements in this advanced system, u-TSN. The purposes of this paper is to introduce the components on u-TSN system, establish new traffic strategies for this system, and then evaluate these strategies by making a comparative study of ITS and using micro traffic simulator, AIMSUN. The strategy evaluated by AIMSUN is position-based multicast strategy which provides traffic information to vehicles using V2I (vehicle to Infrastructure) communication. This paper focuses on the providing real-time route guidance information when congestion is occurred by the incidents. This study estimates total travel time on each route by API modules. Result from simulation experiments suggests that position-based multicast strategy can achieve more optimal network performance and increased driver satisfaction since the total accumulated travel times of both the major road and the total system on position-based multicast strategy are less than those on VMS.

• 대한교통학회지
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• 제14권4호
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• pp.107-129
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• 1996

Recently, surveillance system designed to collect various trsffic information are becoming new areas of development . Among these, the image detector is a ayatem which can measure the travel time and speed in realtime and this is emerging as the most effcient tool to be available in future related areas. But in measuring wide-area information in realtime, the image detector are yet full of problem in its accuracy. The aim of this ahesis is to develop an algorithms which can collect wide-area information such as travel time and travel speed in urban networks and freeways in realtime. The information on wide-area such as travel time and travel speed is important in accomplishing strategic function in traffic control. The algorithm developed from this study is based on the image tracking model which tracks a moving vehicle form image datas collected continuously, and is constructed to perform realtime measurement. To evaluate the performance of the developed algorithms, 600 ind vidual vehicles in total were used as data for the study, and this evaluation was carried out with the differenciation of day and night condition at the access roads in front of AJou University, In the statistical analysis results, the error rate was recorded as 5.69% and it has proved to be applicable on the field in both day and noght conditions.