• Journal of Korean Society of Transportation
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• v.22 no.6
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• pp.145-157
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• 2004

Microscopic freeway simulation models project the uncertain values of performance measures for subject traffic conditions by explaining drivers' driving behavior with lane changing and car-following models. However, the existing lane changing models are limited to gap acceptance oriented passive behavior of drivers and not able to capture more-or-less aggressive driving behavior(e.g. cut-in lane changing) ordinarily obseved in field. This paper suggests the definition of cut-inlane changing and presents its characteristics based on the findings from two different freeway on- and off-ramp sections. In addition, this paper proposes a new lane changing model capable of handling both passive and active drivers' driving behavior for better performance of simulations. The proposed lane changing model was tested with Hanyang Simulatin (HYTSIM), a microscopic freeway simulation program developed for this study. The HYTSIM simulation results reflecting the performance of the proposed lane changing model were compared against the field data. The test results showed that the distribution of gaps collected when vehicles change lanes were statistically identical to the field data at 95% confidence level.

• Journal of Korean Society of Transportation
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• v.28 no.5
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• pp.141-153
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• 2010

The study is about the development of operating speed prediction models aimed for an evaluation of design consistency of four lane rural roads. The main differences of this study relative to previous research are the method of data collection and classification of road alignments. The previous studies collected speed data at several points in the horizontal curve and approaching tangent. This method of collection is based on the assumption that acceleration and deceleration only occurs at horizontal tangents and the speed is kept constant at horizontal curves. However, this assumption leads to an unreliable speed estimation, so drivers' behavior is not well represented. Contrary to the previous approach, speed data were collected with one and data analysis using a speed profile is made for data selection before building final models. A total of six speed prediction models were made according to the combination of horizontal and vertical alignments. The study predicts that the speed data analysis and selection for model building employed in this study can improve the prediction accuracy of models and be useful to analyze drivers' speed behavior in a more detailed way. Furthermore, it is expected that the operating speed prediction models can help complement the current design-speed-based guidelines, so more benefits to drivers as real road users, rather than engineers or decision makers, can be achieved.

• Journal of Korean Society of Transportation
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• v.35 no.3
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• pp.220-233
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• 2017

Traffic volumes are fundamental data widely used in various traffic analysis, such as origin-and-destination establishment, total traveled kilometer distance calculation, congestion evaluation, and so on. The low number of links collecting the traffic-volume data in a large urban highway network has weakened the quality of the analyses in practice. This study proposes a method to estimate the traffic volume data on a highway link where no collection device is available by introducing a spatial statistic technique with (1) the traffic-volume data from TOPIS, and National Transport Information Center in the Ministry of Land, Infrastructure, and (2) the navigation data from private navigation. Two different component models were prepared for the interrupted and the uninterrupted flows respectively, due to their different traffic-flow characteristics: the piecewise constant function and the regression kriging. The comparison of the traffic volumes estimated by the proposed method against the ones counted in the field showed that the level of error includes 6.26% in MAPE and 5,410 in RMSE, and thus the prediction error is 20.3% in MAPE.

• Journal of Korean Society of Transportation
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• v.29 no.5
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• pp.121-138
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• 2011

More affordable and available cutting-edge technologies (e.g., wireless vehicle communication) are regarded as a possible alternative to the fixed infrastructure-based traffic information system requiring the expensive infrastructure investments and mostly implemented in the uninterrupted freeway network with limited spatial system expansion. This paper develops an advanced decentralized traveler information System (ATIS) using vehicle-to-vehicle (V2V) communication system whose performance (drivers' travel time savings) are enhanced by three complementary functions (autonomous automatic incident detection algorithm, reliable sample size function, and driver behavior model) and evaluates it in the typical $6{\times}6$ urban grid network with non-recurrent traffic state (traffic incident) with the varying key parameters (traffic flow, communication radio range, and penetration ratio), employing the off-the-shelf microscopic simulation model (VISSIM) under the ideal vehicle communication environment. Simulation outputs indicate that as the three key parameters are increased more participating vehicles are involved for traffic data propagation in the less communication groups at the faster data dissemination speed. Also, participating vehicles saved their travel time by dynamically updating the up-to-date traffic states and searching for the new route. Focusing on the travel time difference of (instant) re-routing vehicles, lower traffic flow cases saved more time than higher traffic flow ones. This is because a relatively small number of vehicles in 300vph case re-route during the most system-efficient time period (the early time of the traffic incident) but more vehicles in 514vph case re-route during less system-efficient time period, even after the incident is resolved. Also, normally re-routings on the network-entering links saved more travel time than any other places inside the network except the case where the direct effect of traffic incident triggers vehicle re-routings during the effective incident time period and the location and direction of the incident link determines the spatial distribution of re-routing vehicles.

• Journal of the Daesoon Academy of Sciences
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• v.46
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• pp.69-122
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• 2023

This study is an integral exploration of Feng Shui associated with the area around the birthplace of Kang Jeungsan, a sacred site of Daesoon Jinrihoe which holds that the Supreme God descended in human form at that location (through Kang Jeungsan). Through an on-site Feng Shui survey, the main focus of the research method was to explore the Feng Shui configurations around Kang Jeungsan's birthplace especially as it pertains to the connections among geomagnetic veins which lead to the Mount Shiru area. As a method of investigation, this study explored the Feng Shui of Gaekmang-ri Village and the geomantic veins leading up to Mount Shiru. This involved examining the landforms, topography, water flow, and geomantic veins of the area to reveal the overall Feng Shui configurations. Throughout the course of that on-site survey, this study first examined Mount Duseung and Mount Bangjang, also known as Mount Yeongju (sometimes collectively known as Mount Samshin), Mount Dongjuk, Mount Mangje-bong, Mount Maebong, and Mount Shiru. Then, this study stated some of the underlying issues through a scholarly approach based on various theories such as traditional geographical texts and theories on mountain-growth and water-flow from the perspective of Feng Shui. In particular, attention was paid to theoretical aspects of the uninterrupted and undulating flow of the terrain leading to Shiru Mountain. As a result, from a Feng Shui point of view, the connected network geomantic veins in the area of Kang Jeungsan's birthplace and the feng shui features and conditions were all examined through an on-site survey. The survey results revealed that the area forms a large Feng Shui site due to the vast interconnectivity among all the mountains that extend from the Honam vein and form organic relationships with one another. This even includes Mount Samshin in Honam. Considering the geographical conditions that formed a site that enabled harmony between divine beings and humankind, the surrounding place names also provide allusions to the understanding of the birth of Kang Jeungsan as the descent of Supreme God into the human world through the historical figure, Kang Jeungsan. This area is an ideal spot with a propitious spatial arrangement in terms of its Feng Shui. Feng Shui analysis reveals the site to be a place that holds an earth energy-hub transmitting a great energy of nature that cannot be measured by human power alone.