• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.1
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• pp.1-16
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• 2020

With the advent of the fourth industrial revolution era, there has been a growing interest in deep learning using big data, and studies using deep learning have been actively conducted in various fields. In the transportation sector, there are many advantages to using deep learning in research as much as using deep traffic big data. In this study, a short -term travel speed prediction model using LSTM, a deep learning technique, was constructed to predict the travel speed. The LSTM model suitable for time series prediction was selected considering that the travel speed data, which is used for prediction, is time series data. In order to predict the travel speed more precisely, we constructed a model that reflects both temporal and spatial effects. The model is a short-term prediction model that predicts after one hour. For the analysis data, the 5minute travel speed collected from the Seoul Transportation Information Center was used, and the analysis section was selected as a part of Gangnam where traffic was congested.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.2
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• pp.1-11
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• 2014

In this paper, travel speed patterns were deducted based on historical DSRC travel speed data using Decision Tree technique to improve availability of the massive amount of historical data. These patterns were designed to reflect spatio-temporal vicissitudes in reality by generating pattern units classified by months, time of day, and highway sections. The study area was from Seoul TG to Ansung IC sections on Gyung-bu highway where high peak time of day frequently occurs in South Korea. Decision Tree technique was applied to categorize travel speed according to day of week. As a result, five different pattern groups were generated: (Mon)(Tue Wed Thu)(Fri)(Sat)(Sun). Statistical verification was conducted to prove the validity of patterns on nine different highway sections, and the accuracy of fitting was found to be 93%. To reduce travel pattern errors against individual travel speed data, inclusion of four additional variables were also tested. Among those variables, 'traffic condition on previous month' variable improved the pattern grouping accuracy by reducing 50% of speed variance in the decision tree model developed.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.5
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• pp.75-82
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• 2021

The number of traffic accidents is about 230,000, and due to non-recurring congestion and high driving speed, the number of deaths per traffic accident on freeways is more than twice compared to other roads. Currently, traffic information is provided based on nodes and links using the centerline of the road, but it does not provide detailed speed information. Recently, installing sensors for vehicles to monitor obstacles and measure location is becoming common not only for autonomous vehicles but also for ordinary vehicles as well. The analysis using large-capacity location-based data from such sensors enables real time service according to processing speed. This study presents an mapping method for individual vehicle data analysis based on space. The processing speed of large-capacity data was increased by using method which applied a quaternary notation basis partition method that splits into two directions of longitude and latitude respectively. As the space partition was processed, the average speed was similar, but the speed standard deviation gradually decreased, and decrease range became smaller after 9th partition.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.6 no.2
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• pp.81-94
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• 2007

In order to solve the traffic problem which comes to be serious at day, the impotance of Intelligent Transport Systems(ITS) that accomplish information gathering, information processing, information offering with up-to-date scientific techniques is coming to be high. But many local self-government group want to solve the traffic problems with introduction of ITS, however, it is a actual condition where the systematic effective analysis is insufficient. This study establishes the methodology of effective analysis as introduction of ITS, which refers to the inside and outside of the country instance. And then, this research accomplishes direct and indirect effective analysis with the case study. As a result of SUWON ITS introduction effect analysis, the travel speed of TRC mode is increased 31%, and the delay of TRC mode is diminished 43.9% than before introducing case. Most of the citizen felt the improvement effect of ITS system operation, and the majority wanted the expansion of the ITS system in survey. The analysis of economic result that B/C ratio is 5.12. So, The the effect and economic propriety of the ITS enterprise appeared with the fact that it is sufficient.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.5
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• pp.38-48
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• 2017

Link attributes, such as speed, occupancy, and flow, are essential factors for transportation planning and operation. It is, therefore, one of the most important decision-making problems in intelligent transport system (ITS) to determine the optimal location of a sensor for collecting the information on link attributes. This paper aims to develop a model to determine the optimal location of a sensor to minimize the variability of traffic information on whole networks. To achieve this, a network sensor location model (NSLM) is developed to reflect discrete characteristics of data collection. The variability indices of traffic information are calculated based on the summation of diagonal elements of the variance-covariance matrix. To assess the applicability of the developed model, speed data collected from the dedicated short range communication (DSRC) systems were used in Daegu metropolitan area. The developed model in this study contributes to the enhancement of investment efficiency and the improvement of information accuracy in intelligent transport system (ITS).

• Membrane and Water Treatment
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• v.7 no.3
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• pp.223-240
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• 2016

In this study, poly(vinyl-alcohol) and water insoluble ${\beta}$-cyclodextrin polymer (${\beta}$-CDP) cross-linked with citric acid, have been used as macrocyclic carrier in the preparation of polymer inclusion membranes (PIMs) for aniline (as molecule model) extraction from aqueous media. The obtained membranes were firstly characterized by X-ray diffraction, Fourier transform infrared and water swelling test. The transport of aniline was studied in a two-compartment transport cell under various experimental conditions, such as carrier content in the membranes, stirring rate and initial aniline concentration. The kinetic study was performed and the kinetic parameters were calculated as rate constant (k), permeability coefficient (P) and flux (J). These first results demonstrated the utility of such polymeric membranes for environmental decontamination of toxic organic molecules like aniline. Predictive modeling of transport flux through these materials was then studied using design of experiments; the design chosen was a two level full factorial design $2^k$. An empirical correlation between aniline transport flux and independent variables (Poly ${\beta}$-CD membrane content, agitation speed and initial aniline concentration) was successfully obtained. Statistical analysis showed that initial aniline concentration of the solution was the most important parameter in the study domain. The model revealed the existence of a strong interaction between the Poly ${\beta}$-CD membrane content and the stirring speed of the source solution. The good agreement between the model and the experimental transport data confirms the model's validity.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.969-974
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• 2008

As the railway becomes higher, the reliable stability and riding comfort of higher railway are required. To improve the riding comfort of high-speed trains, it is very helpful to use active suspension system for railway. In Japan, the high-speed train, Shinkansen has adopted semi-active suspension system and now it is running in the main trunk. In this paper, the authors introduce several technical trends of vibration control methods of Japanese Shinkansen. And the installation of semi-active suspension to HSR 350x and the test result of test run on the Kyoung-Bu high speed ling are also explained. After development of HSR 350x, new R&D national project of high speed train is progressed by Ministry of Land, Transport, and Maritime Affairs. This project is the development of Electric Multiple Unit of high speed train with 400km/h of maximum test speed. These result would be helpful to progress next generation high speed project.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.1
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• pp.77-84
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• 2015

In 2011, greenhouse gas emissions of transport sector were 85.04 million $tonCO_2eq$ and road emissions accounted for 95% of total emissions in the transport sector. There are few innovative technologies to reduce greenhouse gas emissions aside from eco-driving education and public relation program. Therefore, this paper focused on analyzing optimal acceleration by certain road grades and suggested fuel-efficient driving method for various uphill sections. Scenarios were established by driving modes. Speed profiles were generated by scenarios and speed variations. Each speed profile applied to Comprehensive Modal Emission Model and then each fuel consumption was estimated. Driving mode and speed variation that minimized fuel consumption were driven according to grade percent and uphill distance. When driving in the eco-friendly mode of the driving and speed variation, reduction rate of fuel consumption was evaluated by comparison between eco-driving and cruise control mode. When a vehicle drove under eco-driving mode at 100kph, 90kph and 80kph on uphill road, fuel consumptions were reduced by 33.9%, 30.8% and 5.3%, respectively.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.11
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• pp.38-45
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• 1998

A new set of MQW LD rate equations is proposed that include the interwell carrier transport effect assuming it is dominated by holes. Solving the rate equations, the DC transient response of MQW was obtained and it was shown that uneven carrier concentrations exist due to the interwell carrier transport effect. In addition, it was found that the large number of quantum wells can limit the LD modulation speed and InGaAlAs barriers with smaller valence band offsets can have larger modulation speeds. It is expected that the proposed rate equations can find useful applications in designing the optimal MQW LD structures for high speed applications.

• Journal of Communications and Networks
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• v.12 no.3
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• pp.275-284
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• 2010

The current multihome-aware protocols (like stream control transmission protocol (SCTP) or parallel TCP for concurrent multipath data transfer (CMT) are not designed for high-capacity and large-latency networks; they often have performance problems transferring large data files over shared long-distance wide area networks. It has been shown that SCTP-CMT is more sensitive to receive buffer (rbuf) constraints, and this rbuf-blocking problem causes considerable throughput loss when multiple paths are used simultaneously. In this research paper, we demonstrate the weakness of SCTP-CMT rbuf constraints, and we then identify that rbuf-blocking problem in SCTP multihoming is mostly due to its loss-based nature for detecting network congestion. We present a simulation-based performance comparison of FAST TCP versus SCTP in high-speed networks for solving a number of throughput issues. This work proposes an end-to-end transport layer protocol (i.e., FAST TCP multihoming as a reliable, delaybased, multihome-aware, and selective ACK-based transport protocol), which can transfer data between a multihomed source and destination hosts through multiple paths simultaneously. Through extensive ns-2 simulations, we show that FAST TCP multihoming achieves the desired goals under a variety of network conditions. The experimental results and survey presented in this research also provide an insight on design decisions for the future high-speed multihomed transport layer protocols.