• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.1
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• pp.55-62
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• 2012

This study is to assess the reduction of nonpoint source pollution by applying Best Management Practice (BMP) in Chungju-dam watershed (6,585.1 $km^2$) using Soil and Water Assessment Tool (SWAT). The model was calibrated using 3 years (1998-2000) daily streamflow at 3 locations and monthly water quality of sediment (SS), total nitrogen (T-N) and total phosphorus (T-P) data at 2 locations and validated for another 3 years (2001-2003) data. The 5 BMPs of streambank stabilization, porous gully plugs, recharge structures, terrace, and contour farming were applied to stream and area with the specific criteria of previous researches. Through the parameter sensitivity analysis, the farming practice P-factor and Manning's roughness of stream were sensitive. Overall, the NPS reduction effect was high for streambank stabilization, terrace, and contour farming. At the watershed outlet, the SS, T-P, and T-N were reduced by 64.4 %, 62.8 % and 17.6 % respectively.

• The Journal of the Korea Contents Association
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• v.8 no.4
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• pp.48-54
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• 2008

This paper analyzes cost tradeoffs between memory usage and computation for window-based operators in data stream environments. It identifies generic operator network constructs, and sets up a cost model for the estimation of the expected memory reduction and the computation overheads when window memory relocations are applied to each operator network construct. This cost model helps to identify the utility of window memory relocations. It also helps to apply window memory relocation to improve a query execution plan to save memory usage. The proposed approach contributes to expand the scope of query processing and optimization in data stream environments. It also provides a basis to develop a cost estimation model for the query optimization using window memory relocations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.5B
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• pp.794-800
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• 2010

It is necessary to accurate and efficient management for measured digital data from various sensors in digital marine vessel. It is not efficient that sensor network process input stream data of mass storage stored in database the same time. In this paper, We propose to improve the processing performance of multidimensional stream data continuous incoming from multiple sensor. We propose that we arrange some sensors (temperature, humidity, lighting, voice) and process query based on sliding window for efficient input stream and found multiple query plan to Mjoin method and we reduce stored data using SVM algorithm. We automatically delete that it isn't necessary to the data from the database and we used to ship diagnosis system for available data. As a result, we obtained to efficient result about 18.3% reduction rate of database using 35,912 data sets.

• Journal of Korean Society on Water Environment
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• v.20 no.2
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• pp.151-156
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• 2004

A decision support system, Watershed Analysis Risk Management Framework(WARMF), was applied to the Kyungan Stream watershed, a tributary of Lake Paldang, for calculation of total maximum daily loads(TMDL). The WARMF system was developed by Systech Engineering, USA, and has been successfully used in several watersheds, for TMDL studies. The study area was divided into 14 sub-basins, based on digital elevation model(DEM). The integrated watershed and stream model of WARMF was validated by flow and BOD data measured during the year of 1999. There were reasonable agreements between model results and field data, both in water flow and BOD. The validated Kyungan WARMF was extensively utilized to study the quantitative relationship between waste loads and receiving water quality. Based on TMDL guideline at Paldang Lake and Kyungan Stream, the water quality criterion were set to be 3.0mg/L, 3.5mg/L, and 4.0mg/L at the watershed outlet. The allowable waste loads of BOD, both from point and non-point sources, were determined at each water quality criterion. From this study, it was concluded that the WARMF provided several advantages over the conventional application of watershed and stream models for TMDL study, such as time variable simulations, multiple possible soutions, and reduction loads for goal water quality, etc.

• The Journal of Society for e-Business Studies
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• v.14 no.4
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• pp.75-94
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• 2009

Since XML emerged as a standard for data exchange on the web, it has been established as a core component in e-Commerce and efficient query processing over XML data in ubiquitous computing environment has been also receiving much attention. Recently, the techniques were proposed whereby an XML document is fragmented into XML fragments to be streamed and the mobile clients receive the stream while processing queries over it. In processing queries over an XML fragment stream, the average access time significantly depends on the order of fragments in the stream. As such, for query performance, an efficient organization of XML fragment stream is required as well as the indexing for energy-efficient query processing due to the reduction of tuning time. In this paper, a technique of XML fragment stream organization based on query frequencies, fragment size, fragment access frequencies, and an active XML-based indexing scheme are proposed. Through implementation and performance experiments, our techniques were shown to be efficient compared with the conventional XML fragment stream organizations.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.4
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• pp.112-120
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• 2012

In this paper, we manufactured the wireless video stream system after we scanned EMI(Electro Magnetic Interference)noise in the system. and then, we analysed the noise frequency in the interface, circuit and PCB(Printed Circuit Board). we suggested EMI noise reduction technique. The applied reduction method is low pass filtering, the internal layer placement for high speed video data line and optimization of the system ground condition. the manufactured system improved about 2 ~ 20[dB] margin for EMI limit 40[dBuV/m] at 30 ~ 230[MHz] and 47[dBuV/m] at 230 ~ 1000[MHz].

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.11C
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• pp.1112-1123
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• 2002

Providing a multimedia service requires efficient network bandwidth allocation scheduling. Typically, transmission of information with bursty characteristics, such as a video data stream, utilizes some type of smoothing technique that reduces the transmission rate fluctuation. While capable of a drastic reduction in the peak transmission rate, even the optimum smoothing algorithm proposed to date, however, is rather inadequate for multi-stream applications that share network bandwidth since such an algorithm has been designed and applied toward handling each independent stream. In this paper, we proposed an efficient bandwidth allocation algorithm that addresses these shortcomings. The proposed bandwidth allocation algorithm is divided into two steps, a static bandwidth allocation and a dynamic bandwidth allocation. In the former case, the peak rate reduction is achieved by maintaining the accumulated data in the user buffer at a high level, whereas the concept of real demand factor is employed to meet the needs of multi-stream bandwidth allocation in the latter case, Finally, the proposed algorithm's performance was verified with ExSpect 6.41, a Petri net simulation tool.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2000.10a
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• pp.536-542
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• 2000

The purpose of this study is to evaluate the effect of stream quality by the farmer＇s livestock wastes management in a typical small agricultural watershed. AGNPS model has the capability to adjust the level of pollutant load from farmstead and the fertilization level of upland field. A small agricultural watershed(4.12 $\textrm{km}^2$) which has as livestock farmhouses located in Gosan-myun, Ansung-gun was selected. AGNPS data were prepared by using Arc/info and Idrisi. 4 storm events in 1999 was used for runoff calibration, and 2 storm event which is measured in hourly-base at 4 locations along the stream were used for water quality(TN, TP) calibration. Model＇s behavior to stream quality for 3 cases was investigated. First, the variation of pollution produced from the cattle shed affected little to the stream quality because the cattle sheds were roofed. Second, the good management of ground in farmstead affected to stream quality with 11% and 17% decrease in TN and TP, respectively. Third, the reduction of fertilization level to upland field affected to stream quality with 27.2% and 38.5% decrease in TN and TP, respectively.

• Water for future
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• v.25 no.3
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• pp.79-86
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• 1992

ARF(Areal Reduction Factor) have been developed and used to convert point I-D-F to areal I-D-F in many countries. In Korea, through ARF was calculated in Han river basin by several researchers, it has limit to apply to other regions \ulcorner 새 low density of rainfall gauge station and shortage of data. In this study ARF has developed in areas of high density of rainfall gauge station, Pyungchang river(han river), Wi stream(nakdong river), and Bochung stream(Guem river) basin by fixed-area method. And coefficient of variation of annual mean precipitation was presented to use ARF in othere areas and its applicability was analyzed.

• Korean Journal of Hydrosciences
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• v.4
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• pp.105-116
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• 1993

Areal Reduction Factor(ARF) has been developed and used to convert point Rainfall intensity-Duration-Frequency(I-D-F) to areal I-D-F in many countries. In Korea, though ARF was estimated in Han river basin by several researchers, it has some limitations to apply to other regions due to low denisity of rainfall gauging station and shortage of data. In this study ARF has been developed in area of relatively high density of rainfall gauging station, i.e., Pyungchang river(Han river), Wi stream(Nakdong river), and Bochung stream(Guem river) basin by geographically fixed-area method. And coefficient of variation of mean annual precipitation was presented to use ARE in other areas and its applicability was analyzed.