• Title/Summary/Keyword: Travel range

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Study on Enhancement of TRANSGUIDE Outlier Filter Method under Unstable Traffic Flow for Reliable Travel Time Estimation -Focus on Dedicated Short Range Communications Probes- (불안정한 교통류상태에서 TRANSGUIDE 이상치 제거 기법 개선을 통한 교통 통행시간 예측 향상 연구 -DSRC 수집정보를 중심으로-)

  • Khedher, Moataz Bellah Ben;Yun, Duk Geun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.3
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    • pp.249-257
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    • 2017
  • Filtering the data for travel time records obtained from DSRC probes is essential for a better estimation of the link travel time. This study addresses the major deficiency in the performance of TRANSGUIDE in removing anomalous data. This algorithm is unable to handle unstable traffic flow conditions for certain time intervals, where fluctuations are observed. In this regard, this study proposes an algorithm that is capable of overcoming the weaknesses of TRANSGUIDE. If TRANSGUIDE fails to validate sufficient number of observations inside one time interval, another process specifies a new validity range based on the median absolute deviation (MAD), a common statistical approach. The proposed algorithm suggests the parameters, ${\alpha}$ and ${\beta}$, to consider the maximum allowed outlier within a one-time interval to respond to certain traffic flow conditions. The parameter estimation relies on historical data because it needs to be updated frequently. To test the proposed algorithm, the DSRC probe travel time data were collected from a multilane highway road section. Calibration of the model was performed by statistical data analysis through using cumulative relative frequency. The qualitative evaluation shows satisfactory performance. The proposed model overcomes the deficiency associated with the rapid change in travel time.

Travel Time Prediction Algorithm using Rule-based Classification on Road Networks (규칙-기반 분류화 기법을 이용한 도로 네트워크 상에서의 주행 시간 예측 알고리즘)

  • Lee, Hyun-Jo;Chowdhury, Nihad Karim;Chang, Jae-Woo
    • The Journal of the Korea Contents Association
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    • v.8 no.10
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    • pp.76-87
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    • 2008
  • Prediction of travel time on road network is one of crucial research issue in dynamic route guidance system. A new approach based on Rule-Based classification is proposed for predicting travel time. This approach departs from many existing prediction models in that it explicitly consider traffic patterns during day time as well as week day. We can predict travel time accurately by considering both traffic condition of time range in a day and traffic patterns of vehicles in a week. We compare the proposed method with the existing prediction models like Link-based, Micro-T* and Switching model. It is also revealed that proposed method can reduce MARE (mean absolute relative error) significantly, compared with the existing predictors.

Short-term Prediction of Travel Speed in Urban Areas Using an Ensemble Empirical Mode Decomposition (앙상블 경험적 모드 분해법을 이용한 도시부 단기 통행속도 예측)

  • Kim, Eui-Jin;Kim, Dong-Kyu
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.38 no.4
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    • pp.579-586
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    • 2018
  • Short-term prediction of travel speed has been widely studied using data-driven non-parametric techniques. There is, however, a lack of research on the prediction aimed at urban areas due to their complex dynamics stemming from traffic signals and intersections. The purpose of this study is to develop a hybrid approach combining ensemble empirical mode decomposition (EEMD) and artificial neural network (ANN) for predicting urban travel speed. The EEMD decomposes the time-series data of travel speed into intrinsic mode functions (IMFs) and residue. The decomposed IMFs represent local characteristics of time-scale components and they are predicted using an ANN, respectively. The IMFs can be predicted more accurately than their original travel speed since they mitigate the complexity of the original data such as non-linearity, non-stationarity, and oscillation. The predicted IMFs are summed up to represent the predicted travel speed. To evaluate the proposed method, the travel speed data from the dedicated short range communication (DSRC) in Daegu City are used. Performance evaluations are conducted targeting on the links that are particularly hard to predict. The results show the developed model has the mean absolute error rate of 10.41% in the normal condition and 25.35% in the break down for the 15-min-ahead prediction, respectively, and it outperforms the simple ANN model. The developed model contributes to the provision of the reliable traffic information in urban transportation management systems.

A Study of Measuring Traffic Congestion for Urban Network using Average Link Travel Time based on DTG Big Data (DTG 빅데이터 기반의 링크 평균통행시간을 이용한 도심네트워크 혼잡분석 방안 연구)

  • Han, Yohee;Kim, Youngchan
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.16 no.5
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    • pp.72-84
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    • 2017
  • Together with the Big Data of the 4th Industrial Revolution, the traffic information system has been changed to an section detection system by the point detection system. With DTG(Digital Tachograph) data based on Global Navigation Satellite System, the properties of raw data and data according to processing step were examined. We identified the vehicle trajectory, the link travel time of individual vehicle, and the link average travel time which are generated according to the processing step. In this paper, we proposed a application method for traffic management as characteristics of processing data. We selected the historical data considering the data management status of the center and the availability at the present time. We proposed a method to generate the Travel Time Index with historical link average travel time which can be collected all the time with wide range. We propose a method to monitor the traffic congestion using the Travel Time Index, and analyze the case of intersections when the traffic operation method changed. At the same time, the current situation which makes it difficult to fully utilize DTG data are suggested as limitations.

Methodology for Estimation of Link Travel Time using Density-based Disaggregated Approach (밀도기반 비집계 접근법을 이용한 구간통행시간 추정 방법론)

  • Chang, Hyunho;Lee, Soong-bong;Han, Donghee;Lee, Young-Ihn
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.16 no.5
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    • pp.134-143
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    • 2017
  • In the case of highway, there may be a large number of travel time groups when there are a bus exclusive lane, a rest area, a sleeping shelter, etc. in the corresponding section. In most of the conventional travel time estimation studies, one representative travel time (assuming normal distribution) group is assumed in the low sample collection state, and if it is out of the specified range, it is determined as outliers and then the travel time is estimated. However, if there is a bus exclusive lane, a rest area, or a sleeping shelter in the relevant section, such as the highway, the distribution of travel time will be in the form of a bi-modal or a multi-modal, rather than a regular distribution. Therefore, applying the existing estimation methodology may result in distorted results. To solve this problem, first, it should be reliable even in the case of insufficient number of samples. Second, we propose a methodology to select the representative time group among a number of time groups and to estimate the representative time using individual time data of the selected time group.

Control of Decoupled Type High Precision Dual-Servo (Decoupled Type의 초정밀 이중 서보의 제어에 관한 연구)

  • Nam Byoung-Uk;Kim Ki-Hyun;Choi Young-Man;Kim Jung-Jae;Lee Suk-Won;Gweon Dae-Gab
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.2 s.179
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    • pp.43-50
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    • 2006
  • Recently, with rapid development of semiconductor and flat panel display, the manufacturing equipments are required to have large travel range, high productivity, and high accuracy. In this paper, an ultra precision decoupled dual servo (DDS) system is proposed to meet these requirements. And a control scheme for the DDS is studied. The proposed DDS consists of a $XY{\Theta}$ fine stage for handling work-pieces precisely and a XY coarse stage for large travel range. The fine stage consists of four voice coil motors (VCM) and air bearing guides. The coarse stage consists of linear motors and air bearing guides. The DDS is mechanically decoupled between coarse stage and fine stage. Therefore, both stages must be controlled independently and the performance of the DDS is mainly determined by the fine stage. For high performance tracking, the controller of fine stage consists of time delay control (TDC) and perturbation observer while the controller of coarse stage is TDC alone. With these individual controllers, two kinds of dual-servo control strategies are suggested: master-slave type and parallel type. By simulations and experiments, the performances of two dual-servo control strategies are compared.

Tilling Load Characteristics and Power Requirement for Rotary Tillers (로우터리 경운(耕耘)의 부하특성(負荷特性) 및 소요동력(所要動力)에 관(関)한 연구(硏究))

  • Choi, Kyu Hong;Ryu, Kwan Hee
    • Journal of Biosystems Engineering
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    • v.9 no.2
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    • pp.27-36
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    • 1984
  • This study was carried out to investigate the effects of the tilling depth, tilling travel speed and soil shear stress on the tilling load characteristics and power requirement for rotary tillers. The results obtained from the study are summarized as follows. 1. The average and maximum PTO torque increased as the tilling depth, tilling pitch and soil shear stress increased. A multiple linear regression equation to estimate the average PTO torque in terms of the above parameters was developed. 2. The ratios of maximum PTO torque to the average torque were in the range of 1.17 to 1.65 for the various tilling conditions tested. The variation in PTO torque increased greatly as the tilling pitch and soil shear stress increased, but decreased as the tilling depth increased. 3. Power requirement for the PTO shaft increased with the tilling depth, travel speed and soil shear stress, but decreased slightly as the tilling pitch increased. A multiple linear regression equation to estimate power requirement for the PTO shaft in terms of the above parameters was developed. 4. The specific power requirement for the rotary tiller was in the range of $0.008-0.015ps/cm^2$ for the various tilling conditons tested. The specific tilling capacity decreased as the tilling depth and soil shear stress increased, but increased with the tilling pitch. A multiple linear regression equation to estimate the specific tilling capacity in terms of the above parameters was developed.

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Cladding of Cu and Bronze/Al Alloy by $CO_2$ Laser (고출력 $CO_2$레이저빔에 의한 구리, 청동/알루미늄 합금 클래딩)

  • 강영주;김재도
    • Journal of Welding and Joining
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    • v.15 no.4
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    • pp.109-115
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    • 1997
  • Laser cladding is a technique for modification of metal surface. In this laser cladding experiment a metal powder feeding system was developed for more efficient laser cladding. This system can reduce processing time and be used simpler than the conventional method. The feeding of metal powder has given a rise to the process for sequential buildup of bulk rapidly solidified materials in the form of fine powder stream to the laser cladding process. The parameters of laser cladding have been investigated using this experimental equipment. Bronze on aluminum alloy and copper on aluminum alloy were experimented by using defocused beam, powder feeding system, and gas shielding. Good cladding was achieved in the range of beam travel speed of 2.25m/min. In the case of copper/aluminum and bronze/aluminum substrate, the absorption of laser beam was too high to produce low diluted clad. In the case of copper/1050 aluminum, the optimal laser cladding condition was of laser power of 2.8kW, powder feed rate of 0.31g/s and beam travel speed of 2.25m/min. In the case of bronze/aluminum the optimal condition is of laser power of 2.5kW, powder feed rate of 0.31g/s, and beam travel speed of 2.36m/min.

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Valuing Ecotourism in Palutungan Resort, Gunung Ciremai National Park, Indonesia

  • Adi, Saputra Nur;Lee, Don Koo;Park, Joowon;Lee, Yohan
    • Journal of Forest and Environmental Science
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    • v.32 no.4
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    • pp.344-352
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    • 2016
  • In this paper, we conducted an empirical study on the economic value of Palutungan Resort, Gunung Ciremai National Park (Indonesia), using an individual travel cost method. Gunung Ciremai is the highest mountain in West Java Province which has high biodiversity and constitutes the home range of the endangered species, Nisaetus bartelsi and leopards. Using the individual travel cost method, we estimated the annual consumer surplus of ecotourism for Palutungan Resort to be approximately $19, while its total economic value was $0.23 million. However, Palutungan Resort does not benefit exclusively, because the total economic value is divided diversely among the central government (non-tax revenue), local government (taxes), and local communities, while the transportation agencies, retailers, and gas station companies also reap some valuable benefits. In regard to the benefit allocation, all of the associated parties should participate in the conservation and preservation of natural resources in Palutungan Resort to improve the ecotourism services.