• Journal of Korea Port Economic Association
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• v.27 no.4
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• pp.165-185
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• 2011

Transshipment traffic has significant meanings because it gives positive effects on increasing the container handling volumes in seaports, and revitalizes the regional and national development. Korean container port's transshipment traffic volumes, however, will slowly decrease due to the direct ships' calling into Chinese ports, which recently has a huge development plan. There are a lot of stress on forecasting the transshipment traffic volumes because the Korean container port development plans are designed based on this container traffic which consists of import and export traffic, and transshipment traffic. The transshipment traffic volumes are assumed to occupy 40% of total container traffic volumes. Despite of the importance of forecasting the transshipment traffic, a little studies are suggested using the concepts of the port competitiveness. In this respect, this study aims to estimate the Port Competitiveness Index and Transshipment traffic Volumes using the System Dynamics methodology. As a result, transshipment traffic volumes are predicted as: 20 million TEUs in Korea under the 4% annual increasing rates, 90 million TEUs in China under the 6% annual increasing rates, and 2.5 million TEUs in Japan under the 1% annual increasing rates respectively. The suggested results can be used to enhance the container port competitiveness and produce more transshipment traffic volumes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.7
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• pp.1293-1295
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• 2015

In this letter, an adaptive multi-antenna channel estimation scheme is proposed for uplink multiuser environments such as LTE-A systems to accurately estimate time-varying channels within an affordable complexity. It is confirmed that the proposed channel estimator can achieve accurate channel tracking performance even when various time-varying channel environments and traffic patterns are provided.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.3
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• pp.199-205
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• 2011

This paper presents an algorithm capable of detecting free space for the autonomous vehicle navigation. The algorithm consists of two main steps: 1) estimation of longitudinal profile of road, 2) detection of free space. The estimation of longitudinal profile of road is detection of v-line in v-disparity image which is corresponded to road slope, using v-disparity image and hough transform, Dijkstra algorithm. To detect free space, we detect u-line in u-disparity image which is a boundary line between free space and obstacle's region, using u-disparity image and dynamic programming. Free space is decided by detected v-line and u-line. The proposed algorithm is proven to be successful through experiments under various traffic scenarios.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.871-872
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• 2009

FDP(Flight Data Processor) is processing of flight data for safety air traffic management. FDPs takes core function in aviation safety. Position estimation of aircraft is a key feature of the FDPs. In this paper, the requirements for position estimation of aircraft was defined.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.883-890
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• 2008

Dynamic instability of the railway bridge can cause track irregularities and be directly connected with unstable passenger comfort and derailment of the train. Europe and Japan had studied on this problem for a long time since 1960's, Results of those studies are reflected in recent Eurocode and the bridge design code of Japanese railway bridges. However, even though some traffic safety requirements were applied in Kyoung-bu highspeed railway by French engineers, we experienced many difficulties from insufficient information of criteria background and application procedures. In the present study, various studies will be presented for the estimation of dynamic performance will be proposed and procedures and methods of estimation will be shown.

• Journal of Korean Society of Transportation
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• v.20 no.3
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• pp.159-168
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• 2002

The Highway Capacity Manual(HCM) suggests estimating the average green time for the performance evaluation of the traffic actuated operation and Provides the average green time estimation model. However, the model provides with much room for improvements. This document proposes a new analytical model that overcomes the shortage of the HCM model. The average green times estimated by the HCM model and the proposed model were compared. A computer program using the proposed model was coded for the study, while the ACT348 program was used for the implementation of the HCM model Through the comparison study based on the 1,196 hypothetical simulation data surrogating field data, it was found that the average green times estimated by the proposed model yields much nicer one-to-one linear relationship to the simulation results than the ones from the HCM model in both exclusive-only and shared-permitted cases. The R2 values of the proposed and the HCM models with those cases are 0.90 and 0.56, and 0.86 and 0.57, respectively.

• Journal of Korean Society of Transportation
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• v.24 no.6 s.92
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• pp.33-43
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• 2006

This research is to the selection of optimal probability distribution as well as the estimation for design hourly factor in consideration of traffic characteristic, such as road function, lane number and AADT. To accomplish the objectives, we are applied to various probability distribution using traffic data that observed at permanent traffic count points in 2005. The parameters or the selected 14 probability distribution were estimated based on the method of maximum likelihood and the validity condition of the estimated parameter The goodness-of-fit test, such as chi-square test. was performed as well as the estimation of design hourly factor. As a result, An appropriate distributions of each case were selected : Pearson V for two lane of rural roads, LogLogistic for the four lane of rural roads, LogLogistic for the urban roads, Extreme value for recreation roads. And optimal K factor are as following : $0.1{\sim}0.2 $ for two lane of rural roads, $0.09{\sim}0.14$ for the four lane of rural roads. $0.07{\sim}0.13$ for the urban roads, $0.1{\sim}0.2$ for recreation roads.

• 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.

• Journal of Korean Society of Transportation
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• v.21 no.5
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• pp.61-71
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• 2003

Existent DDHV draws and is calculating K coefficient. D coefficient from sum of traffic volume two-directions time. There is difference of design order and actuality order, error of DDHV estimation value, problem of irregular change etc. of DDHV thereby. In this study, among traffic volume of each other independent two direction(going up, going down), decide design target order in the directional traffic volume, presented way(way) applying without separating K coefficient and D coefficient at the same time. The result were analysis about national highway permanent count point 360 points 30 orders by existing DDHV estimation value method(separation plan) analysis wave and following variation appear. - design order and actuality order are collision at 357 agencies(99.2%) - actuality order special quality : Measuring efficiency of average 80 orders, maximum 1,027 order, minimum 2 orders - error distribution of design order and actuality order : inside 10 hours is(30$\pm$10hour) 106 points(29.4%), 254 points(70.6%) more than 30 orders and $\pm$10 orders error occurrence be - DDHV estimation value : Average 8.4%, maximum 46.7% The other side, average 50 orders. error improvement effect of DDHV 8.4% was analysed that is at design hourly volume computation by inseparability method in case of AADT premises correct thing because inseparability plan agrees actuality order at whole agency with design order and measuring efficiency of DDHV estimation value is "0".t;0".uot;.

• Journal of Korean Society of Transportation
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• v.29 no.1
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• pp.17-27
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• 2011

This paper investigates some critical errors influencing travel demand estimation in Korea Transportation Data Base (KTDB), and through this investigation reasonable traffic analysis zone (TAZ) size and internal trips ratio are analyzed. With varying zone size, the accuracy of travel demand estimation is studied and appropriate level of zone size in KTDB is also presented. For this purpose zonal structure consisting of location of zone centroid, number of centroid connecters has been constructed by social economic index, and then some descriptive statistical analyses such as F-test, coefficient of correlation are performed. From the results, this paper shows that the optimum levels of zone system were various according to the order and capacity of roads, and also shows that the smaller TAZ, the less error in this research. In conclusion, in order to improve accuracy of traffic demand estimation it is necessary to make zone size smaller.