• Title/Summary/Keyword: travel time method

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Modelling and Evaluation of Traffic Flow with Variable Speed Limit on Highway (연속류 가변속도제어 모형개발 및 효과분석)

  • Cho, Hye-Rim;Kim, Young-Chan;Ha, Dong-Ik
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.10 no.1
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    • pp.16-26
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    • 2011
  • Variable speed limit(VSL) is one of the highway ITS techniques designed to prevent accidents and traffic slow down by reducing congestion or speed variation between vehicles and lanes prior to arrive at the accident location by limiting speed. In Korea, while people have recognized the need for variable speed limit beginning with Seoul's urban expressway and installed facilities in order to provide guide for speed limit per lane and lane use, there has not been enough development of algorithm for internal administration as well as research on the basic principles behind administering variable speed limit. This study is for modeling and evaluating the VSL strategies based on the traffic flow theory. Supply-Demand method of the Cell Transmission Model is applied to demonstrate the traffic features and shockwaves to upstream of the bottleneck with/without VSL. We verified the explanation of Cell Transmission Model for the numerical example. and as the result, it is found that VSL strategies can reduce the total travel time in the congested section and variation of the speed. It means VSL is useful to improve the traffic condition and the safety on highway

Hydraulic Relation of Discharge and Velocity in Small, Steep Mountain Streams Using the Salt-dilution Method (Salt-dilution 방법을 이용한 산지소하천의 유량과 유속 관계 분석)

  • Yang, Hyunje;Lee, Sung-Jae;Im, Sangjun
    • Journal of Korean Society of Forest Science
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    • v.107 no.2
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    • pp.158-165
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    • 2018
  • Reach-average velocity prediction in steep mountain streams is important for understanding fluvial processes and practical applications of erosion control in mountain streams. little studies have been conducted in reach-average velocity, but hydraulic researches have been carried out to examine the relationship between discharge and reach-average velocity in torrent reaches using a relatively large amount of discharge data. In this study, a total of 87 data were measured in 8 torrent reaches. Salt-dilution method was used to estimate discharge. Reach-average velocity was calculated from harmonic mean of travel time that were measured by salt-dilution technique. In order to exlpore the hydraulic relation, both discharge and velocity were non-dimensionalized by using $D_{50}$, $D_{84}$, ${\sigma}_{pro}$ and $IPR_{90}$. It also indicated that ${\sigma}_{pro}$ and $IPR_{90}$ were good variables as roughness height for develop the relationship between non-dimensional discharge and velocity in mountain streams. Generally, reach-average velocity could increase exponentially as discharge increases.

An Improved LOS Analysis Method for Pedestrian Walkways Using Pedestrian Space (보행 점유공간을 이용한 보행자도로 서비스수준 분석방법론 개선 연구)

  • JUN, Sung Uk;SON, Yonug Tae
    • Journal of Korean Society of Transportation
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    • v.34 no.2
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    • pp.168-179
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    • 2016
  • This study describes an improved model for estimating pedestrian LOS (Level of Service) by utilizing the space occupied by pedestrians. The method introduced the concept of conflict along the bi-directional pedestrian flow which enables calculating conflict area and average travel time in walking. Especially, the method incorporates the idea of generalized density concept which can consider effective walking area and pedestrian flow rates that might vary during the analysis period. After establishing methodology, adjustments of pedestrian LOS criteria in term of walking space occupied by pedestrians were performed. As a result, walking-occupied space at capacity level is 0.68 and corresponding pedestrian flow rate was calculated as 80 persons/min/m, while different pedestrian-occupied spaces were ordered to classify LOS at the points where the gradient changes. Furthermore, the statistical verification of service levels has shown that there is significant difference among all LOS categories at 5% significance level.

A Study on the Method of Ecological Restoration at the Abandoned Expressways - Focusing on the 192.4k(Incheon) Young-Dong Expressway - (폐고속국도의 생태복원 방안 -영동선 192.4K(인천) 지점을 중심으로-)

  • Cho, Dong-Gil;Choi, Jae-Yong;Jeon, Young-Chul
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.13 no.5
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    • pp.38-50
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    • 2010
  • Expressways are often upgraded by widening the lanes and/or by reshaping the roads to be more linear for faster travel time. However, during the process of improving the route of the expressways, the areas where the old expressways used to be are often unused and abandoned. When these neglected sites are left alone, they often become dump sites causing pollution and impacting the surrounding environment. Therefore, it is important to restore the abandoned expressway sites to its full natural beauty. In this study, the abandoned expressway at the Soksa interchange in Pyungchang county, located in Kangwon province was studied for establishing the model of ecological restoration project. Considering the characteristics of the site, the target flora species was chosen to be Quercus species and the target fauna species as amphibians. After the target species were carefully chosen, each species' habitat requirements were studied in order to figure out the appropriate methods toward habitat restoration specifically for these species. In addition, to determine the most efficient method toward restoration of abandoned expressways, the study utilized the planting hole techniques, the crack techniques, and the colonization techniques. In terms of the spatial organization, public education program is incorporated at the main entrance area and the programs for experimenting, and developing vegetation and habitat restoration techniques are placed in the vicinity. In the master plan-to provide natural ecosystem at the site-ASCON (asphalt concrete) was removed first, then plans for restoration including species' habitat restoration were established. Furthermore, the project included plans for improving water quality polluted through non-point source considering the surrounding nearby road and farm lands. Finally, the study established a planning process that will experimentally apply to the abandoned expressway restoration method. In the future, there will be a continuous monitoring of the methods applied to verify if the restoration methods are effective. Also, new restoration techniques should be available according to a variety of abandoned expressways' characteristics.

A Study on the Benefit of Driving Amenity Based on Highway Density (도로 밀도에 따른 운전쾌적성 편익에 관한 연구)

  • Cho, Hanseon
    • Journal of Korean Society of Transportation
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    • v.31 no.5
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    • pp.48-59
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    • 2013
  • Normally the benefits concerned in the feasibility study for highway constructions are travel time saving, vehicle operation cost, etc. which can be calculated using the simulation tool(EMME3). However, there must be extra benefits of driving amenity improvement that drivers can perceive through decreasing driving fatigue and improving driving comfortability. In this study, the definition of driving amenity was established and a method of estimation for the benefit of driving amenity improvement was developed. Highway type (urban/rural highway) and highway density was considered to estimate the driving amenity. And Double-bounded Dichotomous Choice among Contingent Valuation Method(CVM) was applied to survey the willingness-to-pay of drivers when highway density decreases. Finally the value of driving amenity was estimated using the results of survey and logit medel. As the existing highway density is high, willingness-to-pay increases in both urban and rural highways. Even though the changing rates of highway density are same, willingness-to-pay is different based on the existing highway density.

Query Routing in Road-Based Mobile Ad-Hoc Networks (도로 기반 이동 애드 혹 망에서 질의 처리 방법)

  • Hwang So-Young;Kim Kyoung-Sook;Li Ki-Joune
    • The KIPS Transactions:PartD
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    • v.12D no.2 s.98
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    • pp.259-266
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    • 2005
  • Recently data centric routing or application dependent routing protocols are emerged in mobile ad hoc networks. In this paper, we propose a routing method for query processing in MANET(Mobile Ad hoc NETwork) environment, called road-based query routing, with consideration on real time traffic information of large number of vehicles. In particular, we focus on the method that process arrival time dependent shortest path query in MANET without a central server on the road networks. The main idea of our approach lies in a routing message that includes query predicates based on the road connectivity and on data gathering method in real time from vehicles on the road by ad-hoc network. We unify route discovery phase and data delivery(query processing) phase in our mechanism and reduce unnecessary flooding messages by pruning mobile nodes which are not on the same or neighboring road segments. In order to evaluate the performances of the proposed method, we established a model of road networks and mobile nodes which travel along the roads. The measurement factor is the number of nodes to whom route request is propagated according to each pruning strategy. Simulation result shows that road information is a dominant factor to reduce the number of messages.

Comparison of Dynamic Origin Destination Demand Estimation Models in Highway Network (고속도로 네트워크에서 동적기종점수요 추정기법 비교연구)

  • 이승재;조범철;김종형
    • Journal of Korean Society of Transportation
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    • v.18 no.5
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    • pp.83-97
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    • 2000
  • The traffic management schemes through traffic signal control and information provision could be effective when the link-level data and trip-level data were used simultaneously in analysis Procedures. But, because the trip-level data. such as origin, destination and departure time, can not be obtained through the existing surveillance systems directly. It is needed to estimate it using the link-level data which can be obtained easily. Therefore the objective of this study is to develop the model to estimate O-D demand using only the link flows in highway network as a real time. The methodological approaches in this study are kalman filer, least-square method and normalized least-square method. The kalman filter is developed in the basis of the bayesian update. The normalized least-square method is developed in the basis of the least-square method and the natural constraint equation. These three models were experimented using two kinds of simulated data. The one has two abrupt changing Patterns in traffic flow rates The other is a 24 hours data that has three Peak times in a day Among these models, kalman filer has Produced more accurate and adaptive results than others. Therefore it is seemed that this model could be used in traffic demand management. control, travel time forecasting and dynamic assignment, and so forth.

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Empty Time, Empty Space, and Non(非)-Place in World of Warcraft: The Accumulated Experience and the Recovery in Reality (<월드 오브 워크레프트>(World of Warcraft)의 빈 시간, 빈 공간, 비(非) 장소: 축적된 체험과 실감의 회복)

  • Song, Kyong-Won
    • Cartoon and Animation Studies
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    • s.19
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    • pp.127-143
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    • 2010
  • The purpose of this study is to aesthetically approach a game, which was popular at home, through microscopic analysis on World of Warcraft. World of Warcraft(hereunder called WOW), which improved a game method of MMORPG that had been popular conventionally at home, from several angles, is suggesting new paradigm of MMORPG game. This study aims to propose new vision on game analysis by approaching this new method from the perspective of player. For this, it divided WOW into shift method, instruction implementation method, and communication configuration method, and analyzed this, respectively, by introducing a concept of empty time, empty space, and non-place, which was borrowed from Zygmunt Bauman's "Liquid Modernity". WOW's shifting method rather extends empty time, that is, the waiting time, contrary to the conventional MMORPG, which used a method of removing. Instead of maximally reducing boring, which becomes disturbance of a game, it is what overwhelmingly enlarges time that needs to be waited, thereby being what induces a sense of time, which a player experiences daily life, to the inside of a game. WOW's instruction implementation method offers one of hugely single map instead of zone-system necessary for map loading in the discontinued form. This minutely implements even a greatly insignificant place in playing a game, thereby stirring up a sense of travel, which explores there in reality. Finally, WOW's community configuration method makes a hunting-targeted group clear, which added a concept of hunting called the raid to the existing gild system. The raid, which is a large party of being bound to the inside of Instant Dungeon, clearly gives a performance role to each of party members, thereby allowing the identity in character to be connected directly to the identity of player. Through this, the player filled the suggested 'space' with experience, thereby being able to change it into 'place' that is significant to an individual.

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Predictive Modeling of the Bus Arrival Time on the Arterial using Real-Time BIS Data (실시간 BIS자료를 이용한 간선도로의 버스도착시간 예측모형구축에 관한 연구)

  • Kim, Tae Gon;Ahn, Hyeun Chul;Kim, Seung Gil
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.1D
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    • pp.1-9
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    • 2009
  • Bus information system(BIS), as a part of the intelligent transportation system(ITS), is one of the most advanced public transportation systems which provide the real-time bus traffic information for the users waiting the buses at the bus stop. However, correct bus information data, such as the present bus location, the user waiting time, the bus arrival time, etc. are not provided for the bus users because the proper bus arrival time predictive models are not used yet in most of the cities operating the bus information system, including the metropolitan City of Ulsan. Thus, the purpose in this study is to investigate real-time bus traffic characteristic data for identifying the bus operation characteristics on the arterial under the study in the metropolitan City of Ulsan, analyze real-time bus traffic characteristic data on the ID locations of the arterial under the study, construct the optimal unit segment models for the unit segments which are the bus stop, node and travel section using the exponential smoothing, weighted smoothing and Kalman Filter methods, respectively, and finally suggest the optimal integrated model for predicting the real-time bus arrival time at the bus stop of the arterial under the study.

Development of Bus Arrival Time Estimation Model by Unit of Route Group (노선그룹단위별 버스도착시간 추정모형 연구)

  • No, Chang-Gyun;Kim, Won-Gil;Son, Bong-Su
    • Journal of Korean Society of Transportation
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    • v.28 no.1
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    • pp.135-142
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    • 2010
  • The convenient techniques for predicting the bus arrival time have used the data obtained from the buses belong to the same company only. Consequently, the conventional techniques have often failed to predict the bus arrival time at the downstream bus stops due to the lack of the data during congestion time period. The primary objective of this study is to overcome the weakness of the conventional techniques. The estimation model developed based on the data obtained from Bus Information System(BIS) and Bus management System(BMS). The proposed model predicts the bus arrival time at bus stops by using the data of all buses travelling same roadway section during the same time period. In the tests, the proposed model had a good accuracy of predicting the bus arrival time at the bus stops in terms of statistical measurements (e.g., root mean square error). Overall, the empirical results were very encouraging: the model maintains a prediction job during the morning and evening peak periods and delivers excellent results for the severely congested roadways that are of the most practical interest.