• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.138-138
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• 2021

Flash floods are one of the types of natural hazards which has severe consequences. Flash floods cause high mortality, about 5,000 deaths a year worldwide. Flash floods usually occur in mountainous areas in conditions where the soil is highly saturated and also when heavy rainfall happens in a short period of time. The magnitude of a flash flood depends on several natural and human factors, including: rainfall duration and intensity, antecedent soil moisture conditions, land cover, soil type, watershed characteristics, land use. Among these rainfall intensity and antecedent soil moisture, play the most important roles, respectively. Flash Flood Guidance is the amount of rainfall of a given duration over a small stream basin needed to create minor flooding (bank-full) conditions at the outlet of the stream basin. In this study, the Sejong University Rainfall-Runoff model (SURR model) was used to calculate soil moisture along with FFG in order to identify flash flood events for the Geum basin. The division of Geum river basin led to 177 head-water catchments, with an average of 38 km². the soil moisture of head-water catchments is considered the same as sub-basin. The study has measured the threshold of flash flood generation by GIUH method. Finally, the flash flood events were used for verification of FFG. The results of the validation of seven past independent events of flash flood events are very satisfying.

• Journal of Ecology and Environment
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• v.31 no.3
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• pp.233-241
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• 2008

Functional feeding groups (FFGs) of benthic macroinvertebrates are guilds of invertebrate taxa that obtain food in similar ways, regardless of their taxonomic affinities. They can represent a heterogeneous assemblage of benthic fauna and may indicate disturbances of their habitats. The proportion of different groups can change in response to disturbances that affect the food base of the system, thereby offering a means of assessing disruption of ecosystem functioning. In this study, we used benthic macroinvertebrate communities collected at 650 sites of 23 different water types in the province of Overijssel, The Netherlands. Physical and chemical environmental factors were measured at each sampling site. Each taxon was assigned to its corresponding FFG based on its food resources. A multilayer perceptron (MLP) using a backpropagation algorithm, a supervised artificial neural network, was applied to evaluate the influence of environmental variables to the FFGs of benthic macroinvertebrates through a sensitivity analysis. In the evaluation of input variables, the sensitivity analysis with partial derivatives demonstrates the relative importance of influential environmental variables on the FFG, showing that different variables influence the FFG in various ways. Collector-filterers and shredders were mainly influenced by $Ca^{2+}$ and width of the streams, and scrapers were influenced mostly with $Ca^{2+}$ and depth, and predators were by depth and pH. $Ca^{2+}$ and depth displayed relatively high influence on all four FFGs, while some variables such as pH, %gravel, %silt, and %bank affected specific groups. This approach can help to characterize community structure and to ecologically assess target ecosystems.

• Korean Journal of Ecology and Environment
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• v.37 no.2 s.107
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• pp.137-148
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• 2004

Based on the Merritt-Cummins system, the Korean immature aquatic and semiaquatic insects were reviewed and categorized into 6 different functional feeding groups (FFG) at the generic levels (257 genera belonging to 96 families, 10 orders),Among 257 genera, the most abundant FFG was the predator type consisting of 122(47%) genera. The second and third major groups were gathering-collectors (33genera, 13%) and shredders (21, 8%), respectively. Next group was occupied by scrapers (20,7%), and followed by filtering-collectors (12,5%) and plant-piercers (6, 2%). In addition, a total of 43 genera in 7 orders were remained as uncategorized groups. Both relative degrees of resistance and resilience of each genus were also analyzed to evaluate the role of each FFG in maintaining community stability. The results elucidated that the gathering-collectors and the scrapers could play a role as a pioneer group and a functional mediator in the community, respectively. The results also indicated that the practical use of relative resistance and resilience degrees could be applied to conduct comprehensive studies in stream ecosystems.

• Journal of Fisheries and Marine Sciences Education
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• v.17 no.3
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• pp.324-339
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• 2005

The WTO/DDA Negotiation on the Fisheries Subsidies started by DDA(Doha Development Agenda : 2001.11)at early 2002 has been held about 20 times until the fist half of 2005. The Negotiation will be terminated until the end of 2005 but now, it is impossible to predict the exact conclusion of the Negotiation. There is a sharp conflict of opinion on the WTO/DDA Negotiation on the Fisheries Subsidies between FFG(Fish Friends Groups : USA, New Zealand etc) and Anti-FFG(Rep. Korea, Japan etc). The Fisheries Subsidies is regulated by the WTO/DDA Negotiation that regulates on the subsidies of industrial products, fisheries products, forest products. Considering the progress of the WTO/DDA Negotiation on the Fisheries Subsidies, Guidelines for the Fisheries Subsidies Negotiation were established in Doha Ministerial Declaration at 2001 and a necessity of a special regulation on the Fisheries Subsidies has been discussed from 2002 to 2004. After june, 2004, the Negotiation was proceeding as Rep. Korea, Japan and Taiwan agreed with discussing a special regulation on the Fisheries Subsidies and At 1st, August, 2004, they reached an agreement on a necessity of a special regulation on the Fisheries Subsidies. At Feb, 2005, discussion was suspended because of presenting the joint proposal from 3 countries(Rep. Korea, Japan and Taiwan) and now discussion on the Fisheries Subsidies is giving the first consideration to classification of prohibited/non-actionable subsidies, S&D of a developing countries, small fisheries, problems of farming, grace period etc. From now on, Considering the 18th~the 20th negotiations, it is expected that discussion of fisheries subsidies regulation including property and range of prohibited/non-actionable subsidies, S&D of a developing countries, a definition of small fisheries is accelerated. In this point of view, this paper analyzed and arranged every country's proposals holding our own position and took a survey to fishermen and fisheries experts about prohibited/non-actionable subsidies. In addition, this paper intends to suggest the way of future-negotiation and provides essential data to help government's policy making through analyzing prohibited/ non-actionable subsidies, farming subsidies, S&D of a developing countries, small scale fisheries.

• Proceedings of the Korean Society of Life Science Conference
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• 2008.10a
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• pp.43.1-43.1
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• 2008

• Journal of Aerospace System Engineering
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• v.14 no.5
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• pp.58-65
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• 2020

In this paper, the combat effectiveness of ship guidance rockets to counter the threat of multiple USV(Unmanned Surface Vehicle) was analyzed in three cases. The probability of sinking a number of USVs approaching by distance was compared using various weapon systems and guided rocket systems installed on the naval vessels. As a result of the analysis, it was found that the combat effectiveness of the guided rocket was improved compared to the close defense system of the anti-ship missile installed on the naval vessels.

• Journal of IKEEE
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• v.24 no.2
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• pp.497-501
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• 2020

Dehaze is essential for autonomous driving and intelligent CCTV to operate normally even in foggy weather. The method of airlight estimation is particularly important in dehaze technology. In this paper, we propose a patch-based airlight estimation algorithm and hardware structure that can reduce the amount of unnecessary computation and effectively estimate the airlight in various input images. Proposed algorithm is compared with the popular quad-tree method, and the hardware design is implemented by using XILINX's xc7z045-ffg900 target board as a structure that can satisfy to international standard 4K video in real time.

• Journal of IKEEE
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• v.24 no.1
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• pp.243-247
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• 2020

As the autonomous driving market is rapidly growing, research on autonomous driving is being conducted. Self-driving functions should be performed regardless of the weather for the driver's safety. However, misty weather is difficult to autonomous driving because of the lack of visibility, so a defog algorithm should be used. The image obtained through the fog removal algorithm causes the image quality to deteriorate. To improve this problem, HSV color correction is used to increase the sharpness. In this paper, we propose a color correction hardware using HSV that can cope with 4K images. The hardware was designed with Verilog and verified by Modelsim. In addition, the FPGA was implemented with the goal of Xilinx's xc7z045-2ffg900.

• Journal of IKEEE
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• v.23 no.3
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• pp.984-987
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• 2019

Recently, autonomous driving technology based on object recognition and lane recognition has attracted attention. However, in foggy weather, haze removal technology is needed because it is difficult to recognize surrounding objects. The technology of removing hazy is currently being studied in many ways, and a single image based haze removal algorithms are typical. In this paper, we design the hardware for haze removal by estimating the hazy partical map. Proposed hardware architecture is designed to have a cumulative histogram based filter that does not affect the hardware size even if the window size of filter increases. The hardware design is implemented with XILINX's xc7z045-ffg900 as the target board.

• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.1
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• pp.99-118
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• 2012

The aim of this study is to define a correlation between spatial distribution characteristics of FFG(Functional Feeding Groups) of aquatic insects and related environmental factors in the Geum River based on the theory of RCC(River Continuum Concept). For that objective we had used SMRA(Stepwise Multiple Regression Analysis) method to analyze close relationship between the distribution of aquatic insects and the physical and chemical factors that may affect their inhabiting environment in the study area. And then, a probabilistic method named Frequency Ratio Model(FRM) and spatial analysis function of GIS were applied to produce a predictive distribution map of biota community considering their distribution characteristics according to the environmental factors as related variables. As a result of SMRA, the values of decision coefficient for factors of elevation, stream width, flow velocity, conductivity, temperature and percentage of sand showed higher than 0.5. Therefore these 6 environmental factors were considered as major factors that might affect the distribution characteristics of aquatic insects. Finally, we had calculated RMSE(Root Mean Square Error) between the predicted distribution map and prior survey database from other researches to verify the result of this study. The values of RMSE were calculated from 0.1892 to 0.4242 according to each FFG so we could find out a high reliability of this study. The results of this study might be used to develop a new estimation method for aquatic ecosystem with macro invertebrate community and also be used as preliminary data for conservation and restoration of stream habitats.