• The Journal of the Korea Contents Association
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• v.7 no.1
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• pp.103-115
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• 2007

The vulnerability issue on IEEE 802.1x wireless LAN has been permits the malicious attack such as Auth/Deauth flooding more serious rather than we expected. Attacker can generate huge volume of malicious traffic as the same methods on existing wired network. The objective of wireless IP Traceback is to determine the real attack sources, as well as the full path taken by the wireless attack packets. Existing IP Traceback methods can be categorized as proactive or reactive tracing. But, these existing schemes did not provide enhanced performance against DoS attack on wireless traffic. In this paper, we propose a 'TTL based advanced Packet Marking' mechanism for wireless IP Packet Traceback with wireless Classification function. Proposed mechanism can detect and control DoS traffic on AP and can generate marked packet for reconstructing on the real path from the non-spoofed wireless attack source, by which we can construct secure wireless network based on AP with enhance traceback performance.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.11
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• pp.5005-5009
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• 2016

Introduction: Gutkha contains harmful and carcinogenic chemicals and oral cancer caused by tobacco usage has been reported as a major preventable cause of death worldwide by the World Health Organization. The Telangana state government implemented a ban on gutkha usage starting in 2013 but how effective this ban has been remains unclear. Objectives: The objective of this study was to determine the actual impact of the gutkha ban on users and vendors. Methodology: A cross-sectional study was conducted among gutkha users and tobacco vendors in Ranga Reddy district, Telangana. Based on a pilot study the sample size was determined as 368 and 384 for users and vendors respectively. Two separate questionnaires were administered to these groups. The parameters studied mainly included knowledge regarding the ban, and its impact. Results: About 49.1% of the users were aware of the ban on gutkha. Newspapers were the main source of information regarding the ban as reported by 45.3% of users. After the ban, 29.8% of gutkha users switched to other tobacco products. Awareness of health hazards and non-availability of gutkha was the most important reason stated for quitting or reducing consumption. Conclusion: The perspective of ban when visualized from the users point of view depicted a negative impact while the vendors portrayed a positive impact. Considering the addictive potential of the ingredients of gutkha, recording the effects of the ban on regular consumers and determining whether they can still obtain the products by illicit trade, would be noteworthy for implementation of strict rules.

• Journal of the Korean association of regional geographers
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• v.17 no.2
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• pp.245-258
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• 2011

Best management practices (BMPs) are widely accepted and implemented as a mitigation method for soil erosion and non-point source problems. Estimating the amount of soil erosion and the effectiveness of BMPs using hydrological models help to understand the condition, identify the problems, and make plans for conservation practices in an area, typically a watershed. However, the accuracy and reliability of assessment of BMP impacts estimated by hydrological models can be often questionable due to the uncertainties from various sources including GIS(Geographic Information System) data, scale, and model. This study reviewed the development and the background of hydrological models, and the modeling issues such as the selection of models, scale, and uncertainties of data and models. This study also discussed the advantage of a small scale and spatially distributed model to estimate the impacts of BMPs.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.4
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• pp.9-17
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• 2012

This study was aimed to characterize non-point source (NPS) pollutant runoff and estimate event mean concentrations (EMCs) from a small rural watershed located at the headwater area of the Gyeongan stream. The study watershed consists of the two major landuse, forest (72 %) and paddy field (28 %). The nine rainfall events ranging from 18.5 to 192.6 mm in amount were monitored in this study. Stream flow was measured at the watershed outlet using a water level gauge, while a number of water samples for each event were collected and analysed for water quality. Event pollutant loads varied greatly depending on rainfall events varying from 22.6 to 3,134.2 mg/L, 0.32 to 24.56 mg/L, 0.090 to 1.320 mg/L, and 2.3 to 149.8 mg/L for SS, TN, TP, and COD, correspondently. The respective mean EMCs were estimated by 104.2, 1.00, 0.168, and 7.9 mg/L. The Pearson correlation analysis showed that COD EMC was significantly correlated with those of SS, TN, and TP. Rainfall runoff ratio appeared to be negatively correlated with EMCs of SS, TP, and COD, although not statistically significant. The event loads from the largest rainfall was greater than the sum of those from the remaining eight events. The study results suggest that the appropriate management of intensified storm events are of greater importance in curbing NPS loads, while the estimated EMCs provide base data for the unit pollutant loads determination for the forest-paddy composite upstream watershed.

• Journal of The Korean Society of Agricultural Engineers
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• v.53 no.6
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• pp.111-119
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• 2011

The main objective of this study was to evaluate the effects of control-release fertilizer (CRF) on pollutant loadings from a small watershed. The Baran watershed, 386 ha in size, was selected as the study site, and the AGNPS (Agricultural Non-point Source Pollution) model was used to evaluate the effects of fertilizer types. Digital maps of digital elevation (DEM), slope distribution, channel, flow direction, landuse, soil, and curve number were extracted from the study watershed. Model parameters related to hydrology and water quality were calibrated and validated by comparing model predictions with the observed data collected for 2 years (1999 to 2000). Calibration and validation resulted in $R^2$ values of 0.75-0.91 for all the water quality parameters. All the paddy fields (21.2 %) of the study watershed were sprayed by either CRF or NPK (standard fertilizer). In CRF application, total nitrogen (TN) load was 4.9% less than NPK application, however total phosphorus (TP) load was 0.7 % more than NPK application. In CRF application, considering only paddy fields in the study area, TN load was 38.7 % less than NPK application. Using CRF in paddy fields could be one of the ways to reduce pollutant loadings from agricultural watersheds, however, in order to confirm it, more researches about effects of using CRF are necessary.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.4
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• pp.119-122
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• 2008

The paved area like a road or bridge where having high impermeable rates were accumulated various non-point sources(NPS) by passing vehicles during dry season periods. They are flowed in the river continuous when it rains and could negative impact on environment. Therefore, this study monitoring NPS for two years and determinating for each pollutant EMCs and mass loading. The result shows that the EMC ranges are 11.60$\sim$230.90 mg/L for TSS, 4.58$\sim$31.90 mg/L for BOD, 1.86$\sim$9.20 mg/L for TN and 0.14$\sim$1.55 mg/L for TP. Also, the ranges of washed-off mass loading are determined to 0.78$\sim$18.01 kg/day for TSS, 0.47$\sim$1.17 kg/day for BOD, 0.00$\sim$0.01 kg/day for Pb and 0.01$\sim$0.06 kg/day for Zn.

• Journal of Korean Society on Water Environment
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• v.26 no.3
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• pp.413-419
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• 2010

A silica mine monitoring was conducted from March to December in 2008 to measure rainfall, runoff amounts and pollution loads. A total of 13 rainfall-runoff events were measured and analyzed with respect to runoff ratio, pollutant concentration and load, and initial flush. Over rainfall-runoff events, 95% confidence range of SS concentration was 942.5~2,056.2 mg/L. Other measured water quality indices also showed relatively large variation. This wide concentration variation was thought to be caused by the bare working ground of the mine that was used to store, process and transport the mined silica. Total pollution load of the 13 rainfall-runoff events was SS 17,901 kg/ha, $COD_{Cr}$ 160.9 kg/ha, $COD_{Mn}$ 111.24 kg/ha, BOD 79.6 kg/ha, T-N 13.8 kg/ha, T-P 3.5 kg/ha, and TOC 39.3 kg/ha. Initial flush was not well observed except SS. Very high SS concentration and load was occurred when rainfall was large. Therefore, it was recommended to manage the bare ground not to discharge excessive pollutants during wet days by covering the ground or constructing runoff treatment systems such as a sediment basin.

• Journal of Korean Society on Water Environment
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• v.25 no.5
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• pp.785-791
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• 2009

Using artificial rainfall simulator, the soil loss, which is deemed as the most cause of muddy water problem among Non-point source (NPS) pollutant, was studied by the analysis of direct runoff, groundwater discharge, and soil water storage properties concerned with rainfall intensity, slope of area, and land cover. The direct runoff showed increasing tendency in both straw covered and bared soil as slope increases from 5% to 20%. The direct runoff volume from straw covered surface were much lower than bared surface. The infiltration capacity of straw covered surface increased, because the surface sealing by fine material of soil surface didn't occur due to the straw covering. Under the same rainfall intensity and slope condition, 2.4~8.2 times of sediment yield were occurred from bared surface more than straw covered surface. The volume of infiltration increased due to straw cover and the direct runoff flow decreased with decrease of tractive force in surface. To understand the relationship of the rate of direct runoff, groundwater discharge, and soil water storage by the rainfall intensity, slope, and land cover, the statistical test was performed. It shows good relationship between most of factors, except between the rate of groundwater storage and rainfall intensity.

• Journal of Wetlands Research
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• v.19 no.4
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• pp.393-402
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• 2017

This study was designed to provide basic information for an effective wetland design by analyzing the correlation between wetland size and water quality improvement effect in regard to an artificial wetland inside the Biopark Basin by means of applying the modelling technique. It is expected that this study will contribute to a rational design, operation and management of the artificial wetland in the basin. The following conclusions are obtained through the results and discussion of this study. The results of respective design scenarios that expanded the size of the artificial wetlands in the range of 0-100 % showed that when the wetland is 'expanded 75 % compared with the existing size', water quality improved best compared with the design criteria of 'the current operation of the existing size'. The improved data are: 66.7 % in BOD5, 69.9 % in TSS, 64.7 % in T-N, 85.5 % in T-P and 51.8 % in Chl-a. In particular, with the exception of Chl-a, water quality improvement stood out in the quality items in summer among the four seasons. And that there in no direct relationship between facility scale and water quality improvement.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.92-96
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• 2008

최근에 이상기후로 인한 집중호우는 단시간의 높은 강우 강도의 발생을 증가시켜 재해 유발의 측면에서 뿐만 아니라 유역 내 비점오염원이 합류식 관거의 월류수인 CSOs(Combined Sewer Overflows)의 형태로 강우와 함께 유입되어 수질 및 환경을 오염시키는 문제점이 발생한다. 이에 따라 월류수의 유출특성에 대한 정량적인 분석을 통하여 유량 및 수질 등의 오염부하량에 대한 적절한 저감 방안이 요구되고 있는 실정이다. 이에 본 연구에서는 비점오염원의 농도가 상대적으로 높은 도시유역에 강우로 인한 월류수의 유출 특성 변화를 분석함과 동시에 월류수가 하천에 방류되었을 때의 하천에 미치는 영향 분석을 통하여 하천의 효율적인 수질 관리 방안을 제시하고자 한다. 경기도 구리시를 대상유역으로 선정하였으며, 도시 강우-유출 모델인 SWMM을 사용하여 유역의 유출량 및 월류수의 수질 모의를 수행하였으며, 유역의 최종 방류구에 비점오염 저감을 위해 설치된 저류지를 통해 하천으로 배출되는 유출수와의 연계는 미국 환경청에서 개발된 WASP 모델을 적용하여 왕숙천 본류에 대한 월류수 변화가 하천에 미치는 영향을 분석하였다. 저류지 설치 전 후의 하천에 월류수가 미치는 영향을 BOD 농도를 중심으로 비교 분석하였다. 분석 결과 저류지 설치 후 BOD 농도의 저감율은 설치 전 보다 최소 1.9%, 최대 81.2%의 저감 효과가 있는 것으로 분석되었다. 향후 신뢰도 높은 수질모의를 위해서는 월류수 발생시 월류수와 하천의 지속적인 모니터링을 통해 현장 여건을 반영할 수 있는 입력변수의 도출이 매우 중요한 것으로 나타났다.