• Journal of Korea Water Resources Association
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• v.49 no.6
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• pp.495-507
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• 2016

This study aims at hydrologically demonstrating the universality of power law distribution by analyzing runoff aggregation structures of river basins. Power law distribution is fitted to cumulative drainage area of basins of interest by maximum likelihood, which results in the power law exponents. And then those exponents are assessed in terms of the shape of catchment plan-form. As a main result all of the basins in this study have similar distributions of catchment area. The exponents from this study tend to be higher than the ones from previous researches reflecting self-similar property of the catchment plan-forms of interest. Further study is required about the universality of power law distribution by means of the more realistic flow routing scheme within the framework of DEM.

• IEIE Transactions on Smart Processing and Computing
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• v.5 no.3
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• pp.193-198
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• 2016

Lane change is an important issue in microscopic traffic flow simulations and active safety. Overtaking and changing lanes are dangerous driving maneuvers. This approach presents a lane-changing system based on speed and a minimum gap between vehicles in a vehicular ad hoc network (VANET). This paper proposes a solution to ensure the safety of drivers while changing lanes on highways. Efficient routing protocols could play a crucial role in VANET applications, safeguarding both drivers and passengers, and thus, maintaining a safe on-road environment. This paper focuses on the development of an intelligent transportation system that provides timely, reliable information to drivers and the concerned authorities. A test bed is created for the techniques used in the proposed system, where analysis takes place in an on-board embedded system designed for vehicle navigation. The designed system was tested on a four-lane road in Neemrana, India. Successful simulations were conducted with real-time network parameters to maximize quality of service and performance using Simulation of Urban Mobility and Network Simulator 2 (NS-2). The system implementation, together with the findings, is presented in this paper. Illustrating the approach are results from simulation using NS-2.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.9
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• pp.4287-4306
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• 2016

Network resilience provides an effective way to overcome the problem of network failure and is crucial to Internet protocol (IP) network management. As one of the main challenges in network resilience, recovering from link failure is important to maintain the constancy of packets being transmitted. However, existing failure recovery approaches do not handle the traffic engineering problem (e.g., tuning the routing-protocol parameters to optimize the rerouting traffic flow), which may cause serious congestions. Moreover, as the lack of QoS (quality of service) restrictions may lead to invalid rerouting traffic, the QoS requirements (e.g., bandwidth and delay) should also be taken into account when recovering the failed links. In this paper, we first develop a probabilistically correlated failure model that can accurately reflect the correlation between link failures, with which we can choose reliable backup paths (BPs). Then we construct a mathematical model for the failure recovery problem, which takes maximum rerouting traffic as the optimizing objective and the QoS requirements as the constraints. Moreover, we propose a heuristic algorithm for link failure recovery, which adopts the improved k shortest path algorithm to splice the single BP and supplies more protection resources for the links with higher priority. We also prove the correctness of the proposed algorithm. Moreover, the time and space complexity are also analyzed. Simulation results under NS2 show that the proposed algorithm improves the link failure recovery rate and increases the QoS satisfaction rate significantly.

• Journal of the Korean Society of Industry Convergence
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• v.11 no.1
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• pp.11-18
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• 2008

After execute quantitative analysis that choose station and compose floodgate quality of water net and use floodgate data and quality of water data analysis target Sign of the cock as 1 dimension access for Non-point pollution source pollution and estimate of Gaeuncheon's at Kyongsangbukdo report to the Throne in this research, presented parameter conclusion notation model (AGNPS) in real condition of our agricultural area through comparison with spot value and result is as following in reply. With result observation and analysis result of the AGNPS model the comparison which it will pay from the hazard which it analyzes 2005, the rainfall thought which is used in the analysis to select 8 heavy rain thoughts 2005 July - is data until of September. Actual amount of rainfall 6.0~195.0 mm one time the antecedent precipitation showed API5 case 0.0~507.0mm and were observed peak flows (Qpeak) each from the P-1 $0.026m^3/sec{\sim}9.265m^3/sec$, from the P-2 $0.010m^3/sec-2.747m^3/sec$ and from the P-3c $0.064m^3/sec-13.482m^3/sec$ to show. Also amendment AMC condition it will be cool and it uses and the AGNPS model conference the result which it occurs, analysis and regression analysis of actual flow for as 0.992 very the possibility of getting the result which is good there was a decisive coefficient which is cool. But the gun is (T-P) with the total nitrogen (T-N) decisive coefficient each as 0.794 and 0.849 the presumption which is reliability generally will pay and with the fact that it will be the possibility of getting it is judged.

• Water for future
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• v.26 no.3
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• pp.125-135
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• 1993

This study was conducted for two purposes. The first was the selection of the proper model for the urban runoff, and NPS(non-point source) loads and the second was the adjustment of the selected model through the calibration and the verification of the observed data on an urban drainage basin. The selected model for this study was the Storm Water Management Model(SWMM) developed and maintained by the US Environmental Protection Agency(EPA). In particular, the Runoff Block for the surface discharge and the Transport Block for the flow routing was used. The study basin is Youngdu basin, which is a typical developed urban drainage basin. The four rainfall events for the runoff and the two for the four NPS pollutants(SS, BOD, COD and TN) were used for the calibration and the estimation of the model parameters. This study performed the calibration with regard to the peak discharge, the time to peak discharge, the volume and the relative error for three items. It was shown that SWMM can successfully be used for the prediction of the runoff and the NPS pollutants discharge. The result of this study can be used as the basis for the analysis of the correlation between the runoff and the NPS pollutants discharges, and the analysis of the mass balance with the monthly and annual NPS loads in an urban drainage basin.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.213-221
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• 2005

In the present maritime traffic conditions of Gwangyang harbor, there exists many hazardous factors which may lead to huge accidents including marine oil pollution. To mitigate the danger to vessels in Gwangyang harbor and to secure the safety of maritime environment, we established one way traffic between No.3 Route and No.4 Route, Designed of deep water line on No.3 route, Extended one-way route for Myo-Do Passage etc.

• Journal of Advanced Navigation Technology
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• v.16 no.5
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• pp.744-751
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• 2012

Air Traffic Management(ATM) is to control air traffic flow quickly and safely. For efficient ATM, the ability which calculate optimal route using filight plan and filght information is required. Especially for the time-sensitive air cargo, it is essential. In this paper, therefore, we present a dynamic route search algorithm which calculate optimal route dynamically. The conventional method using Dijkstra algorithm has a problem that recalculate the entire route when some airways are closed. However, the proposed algorithm recalculates only affected waypoints, so it finds optimal route quickly and accurately. Comparisons with the conventional method and the proposed algorithm show that the proposed algorithm provides better.

• Magazine of the Korean Society of Agricultural Engineers
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• v.19 no.2
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• pp.4377-4384
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• 1977

The curvilinear hydrograph can be replaced by an equivalent triangular hydrograph which is more easily constructed and, for routing through reservoirs or stream channels, gives results about as accurate as those obtained using the curvilinear hydrograph. A synthetic hydrograph is prepared using the data from a number of watersheds to develop a dimensionless unit hydrograph applicable to ungauged watersheds. The dimensionless unit hydrograph for the NakDong River Basin was prepared from the unit hydrographs of a variety of nine subwatersheds. The equation for the peak rate of flow (unit volume of runoff in 1.0mm) was derived as {{{{ { q}_{p } = { 0.21AR} over { {T }_{p } } }}}} The results summarized in this study are as follows: 1) It found that the watershed lag time (Lg, hrs) could be expressed by Lg=0.253(L.Lca)0.4171 The product L.Lca is a measure of the size and shape of the watershed. Correlation coefficient for Lg was 0.97 which defined with high significance. 2) The base length of the unitgraph, in hours, was adopted as Tb=17.51+2.073Lg with high significant correlation coefficient, 0.92. 3) Time in hour from start of rise to peak rate (TP) generally occured at the position of 0.289 Tb with some indication of higher values for larger watershed. 4) Triangular hydrograph is a dimensionless unitgraph prepared from the 40 unitgraphs. The equation is shown as {{{{ { q}_{p } = { K.A.R} over { { T}_{p } } }}}}. The constant K=0.21 is defined to NakDong River basin. 5) In the light of the results analyzed in this study, average errors in the peak discharge of the Trjangular unitgraph was estimated as 5.34 percent to the peak of observed average unitgraph. Each ordinate of the Triangular unitgraph was approached closely to the observed one.

• Journal of Korea Water Resources Association
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• v.38 no.7 s.156
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• pp.585-593
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• 2005

Recent concerns regarding protecting, identifying, isolating, redundant routing and dewatering of subsystems of water distribution networks have led to the realization of the importance of valves in these systems. Valves serve two purposes namely, flow and pressure control and isolating subsystems due to breakage or contaminant containment. In this paper, valves are considered from the point of view of subsystem isolation. When a water main is required to be closed, it may be in general necessary to close several other pipes in addition to the broken pipe itself depending on the distribution of adjacent valves. This set of pipes is defined as a segment. In this paper a segment analysis for isolating pipes is present and based on the segment analysis, we suggested the Valve Importance Index and the 7 performance indicators to evaluate the system performance. The suggested methodology is applied to a real network to verify the applicability of the methodology.

• Journal of Korea Water Resources Association
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• v.51 no.5
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• pp.405-415
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• 2018

Hydraulic variables such as discharge coefficient, gate opening, and upstream water depth are required to calculate the discharge of vertical lift gate. It is very important for a precise gate design, because it may affect the rest, to predict the behavior of gate opening during operation. In this study, an equation by which gate opening could be predicted with any upstream water depths was derived from the relation between the calculated value from buoyancy theory and measured one from experiment for a floating gate model. Downpull force was the reason for the differences between the calculated and the measured and it was verified using pressure coefficient. Also, the relation of discharge coefficient with gate opening ratios was derived. The derived relations were used for flood routing and it was realized that downpull force effect should be fully taken into account during gate design.