• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2020.11a
• /
• pp.175-176
• /
• 2020

시뮬레이션 기반의 해상교통 분석 방법은 대상 항만의 항적 데이터를 이용하여 교통 특성 모델을 구축하고, 이를 통해 해상교통 현상을 재현함으로써 분석을 수행하는 방법이다. 교통 특성 모델은 교통 현상을 수치적으로 표현한 일반화 된 모형을 말하며, 모델링 작업에 많은 시간과 노력이 소요된다. 본 논문에서는 해상 교통 특성을 생성하기 위한 자동화 된 프로세스를 제안하며, 실제 목포항의 항적 데이터에 적용하여 교통특성 정보 생성 방법으로서의 활용 가능성을 검토하였다.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2019.05a
• /
• pp.240-244
• /
• 2019

본 연구에서는 2차원 수치모형(Nays2DH)을 적용하여 금강 상류에 건설된 세종보를 중심으로 보 개방 후에 홍수량 변화에 의한 하도의 지형변화 과정을 분석하였다. 수치모의를 위한 홍수량은 금남수위표에서 2018년 1월부터 2018년 12월까지 각 시간별 유량을 일반화(normalizing) 하여 하였다. 부정류 홍수량은 2018년 7월의 홍수량 $3,341m^3/s$을 적용하였으며, 부정류의 첨두유량($3,341m^3/s$)이 발생시간은 28시간이고 유출량은 $108.1m^3/s$으로 설정하였다. 수치모의 시간은 120시간으로 설정하여 사주의 발달, 이동, 사주의 형상 및 하도 지형변화를 분석하였다. 첨두유량은 $2,281m^3/s$, 2차 첨두유량은 $3,515m^3/s$, 3차 첨두유량은 $4,259m^3/s$으로 각각 26시간, 107시간, 200시간 동안 발생하는 부정류를 적용하였다. 수치모의 구간은 세종보를 중심으로 상하류 6.5 km 구간을 설정하였으며, 보는 완전히 개방된 것으로 설정하였다. 단일 홍수가 유입될 때 보다, 3개의 홍수가 연속으로 유입될 때에는 보 상류에서 사주의 크기가 크고, 사주의 수가 증가하며, 저수로의 변화가 다양하였다. 흐름이 집중되는 구간에서 하상은 깊게 세굴 되어 하천구조물의 안정과 주의가 필요하다. 그러나 하도의 다양성과 역동성이 크게 개선되는 특성을 보여주었다. 하상의 종방향 특성을 고려할 때, 세종보 하류에서는 하상고가 상승하는 특성을 보여 주었으나, 하상고가 불규칙한 특성을 보여주었다. 이는 단일홍수에 비해하여 하도의 역동성이 큰 것을 의미한다, 사주의 이동속도는 1차 첨두유량일 때 가장 빠르게 나타났지만, 이후 2차 및 3차의 유량이 더 많았지만 사주의 이동속도가 감소하였다. 보를 완전개방 하였을 때는 흐름이 안정화 되어 이동속도 변동폭이 작아졌다.

• Journal of Korean Society of Transportation
• /
• v.34 no.2
• /
• pp.168-179
• /
• 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.

• Journal of Korean Society of Transportation
• /
• v.26 no.4
• /
• pp.41-49
• /
• 2008

Signalized intersection analysis using lane groups often generalizes distinct characteristics of individual lanes. An individual lane level analysis procedure is proposed. The method can assess individual lane LOS without additional data collection efforts. Analysis results of the proposed method were compared with the current HCM analysis results and outputs of aaSIDRA, which can calculate intersection performance lane-by-lane. The results showed individual lane analysis mostly produces similar results with HCM and aaSIDRA. However, lane analysis results for permitted left lanes showed some differences with aaSIRDRA due to the different method of assessing saturation flow rate of the permitted left turn movement. It is expected that the proposed method could complement the weaknesses of current HCM signalized intersection analysis.

• Journal of Korea Water Resources Association
• /
• v.54 no.8
• /
• pp.629-641
• /
• 2021

In this study, a two-dimensional numerical model (Nays2DH) was applied to analyze the process of morphological changes in the river channel bed depending on the changes in the amount of flooding after fully opening the Sejong weir, which was constructed upstream of the Geum River. For this, numerical simulations were performed by assuming the flow conditions, such as a non-uniform flow (NF), unsteady flows (single flood event, SF), and a continuous flood event (CF). Here, in the cases of the SF and CF, the normalized hydrograph was calculated from real flood events, and then the hydrograph was reconfigured by the peak flow discharge according to the scenario, and then it was employed as the flow discharge at the upstream boundary condition. In this study, to quantitatively evaluate the morphological changes, we analyzed the time changes in the bed deformation the bed relief index (BRI), and we compared the aerial photographs of the study area and the numerical simulation results. As simulation results of the NF, when the steady flow discharge increases, the ratio of lower width to depth decreases and the speed of bar migration increases. The BRI initially increases, but the amount of change decreased with time. In addition, when the steady flow discharge increases, the BRI increased. In the case of SF, the speed of bar migration decreased with the change of the flow discharge. In terms of the morphological response to the peak flood discharge, the time lag also indicated. In other words, in the SF, the change of channel bed indicates a phase lag with respect to the hydraulic condition. In the result of numerical simulation of CF, the speed of bar migration depending on the peak flood discharges decreased exponentially despite the repeated flood occurrences. In addition, as in the result of SF, the phase lag indicated, and the speed of bar migration decreased exponentially. The BRI increased with time changes, but the rate of increase in the BRI was modest despite the continuous peak flooding. Through this study, the morphological changes based on the hydrological characteristics of the river were analyzed numerically, and the methodology suggested that a quantitative prediction for the river bed change according to the flow characteristic can be applied to the field.