• Journal of Korean Society on Water Environment
• /
• v.22 no.2
• /
• pp.294-299
• /
• 2006

The Ministry of Environment in Korea has introduced Total Pollution Load Management System (TPLMS) in major 4 large rivers to protect the water quality from possible pollutants. In order to successfully achieve the TPLMS, the nonpoint source should be controled by applying the best management practices in highly polluted areas. Of the various nonpoint sources, the highways are stormwater intensive landuses because of its high imperviousness and high pollutant mass emissions. The EMC (Event Mean Concentration) is an important parameter to correctly determine the pollutant mass loadings from nonpoint sources. However, it has wide ranges because of various reasons such as first flush phenomenon, rainfall and watershed characteristics. Even though the EMC is closely related to the first flush phenomenon, the relationship have not proven until present. Therefore, in this paper, the dynamic EMC method will be introduced to clearly make the relationship between EMC and first flush phenomenon. Also by applying the dynamic EMC method to monitored data, we found that the highly concentrated stormwater runoff was washed off within 20~50 minutes storm duration. The first flush criteria for economical treatment was also determined to 5~10 mm (mean=7.4 mm) as a cumulative rainfall.

• Journal of the Korean Society for Railway
• /
• v.8 no.4
• /
• pp.308-313
• /
• 2005

In order to successfully propel the stormwater management program, administration plan of stormwater management is enacted in Spring, 2005. Hereafter, in a newly developing area such as a railway station, the best management practices should be established to control the nonpoint pollutant. Construction of a railway station means the increasing of imperviousness rate and lots of nonpoint pollutant emissions during rainfall. Therefore this research was performed to determine the pollutant EMC and to suggest the possible best management practice for treating nonpoint pollutants from a railway station. The $95\%$ confidence intervals of pollutant EMC were ranged to 69.4-115.2mg/L for TSS, 132.7-190.4mg/L for COD, 5.4-15.1ug/L for Oil & Grease, 4.9-12.4mg/L for TKN and 568.4-620.1ug/L for TP. The first flush criteria was ranged to 5-10mm accumulated rainfall using dynamic EMCs, Also laboratory reactor testing was performed. It shows that Zeolite media is useful for removing the washed-off pollutants from a railway station, especially for metal ions.

• Journal of Korea Multimedia Society
• /
• v.9 no.5
• /
• pp.658-670
• /
• 2006

As the educational media tends to be more digitalized and individualized, the learning paradigm is dramatically changing into e-learning. Existing on-line courseware gives a learner more chances to learn when they are home with their own PCs. However, it is of little use when they are away from their digital media. Also, it is very labor-intensive to convert the original off-line contents to on-line contents. This paper proposes education mobile contents(EMC) that can supply the learners with dynamic interactions using various multimedia information by recognizing real images of off-line contents using mobile devices. Content-based image retrieval based on object shapes is used to recognize the real image, and shapes are represented by differential chain code with estimated new starting points to obtain rotation-invariant representation, which is fitted to computational resources of mobile devices with low resolution camera. Moreover we use a dynamic time warping method to recognize the object shape, which compensates scale variations of an object. The EMC can provide learners with quick and accurate on-line contents on off-line ones using mobile devices without limitations of space.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 1993.10a
• /
• pp.896-905
• /
• 1993

Thin-layers of wheat and barley are dried at near-ambient temperatures(3.5$^{\circ}C$ -5$0^{\circ}C$) in order to obtain the intrinsic drying data. The well established apparatus was modified to enable it to record all the sample weight data in still air by using a purpose -built automatically controlled sliding valve. The air could be diverted in less than 0.5seconds and a 7 second period was required to attain a steady weight reading. With this apparatus, very smooth drying curves were obtained. The data of sample weight , drying temperature and dew point temperature wee recorded continuously . The drying process was terminated when the moisture content change in 24 hours was less than 0.004 d.b. This was achieved by drying a sample for about a week . The final points were recorded as the dynamic equilibrium moisture content(EMC). The drying data were than fitted to the exponential Newton model and the dynamic EMC data were fitted to the Modified-Chung-Pfost Model . All the fitted parameters are given and comparison is made with previous published data. The comparisons who that the current drying constants are lower than the previous data, the dynamic EMC data obtained for wheat and barely agree with the previous data. The results show that to obtain the drying constant in the exponential Newton model, adequate drying time is necessary.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.49 no.3
• /
• pp.165-171
• /
• 2000

This paper proposes a technique to design of air-core type Linear DC Motor(LDM) by using Equivalent Magnetizing Current(EMC) method and has performed its dynamic analysis. The magnetic flux density differ in accordance with airgap position due to difference of mechanical and magnetic air gap length and the coil shape has an influence on the thrust. Therefore, the analysis of magnetic field due to the magnets is carried out by EMC. The phenomena according to the various coil various coil shape under the same Magneto Motive Force(MMF) has been analyzed and its result is applied to the design process. The appropriateness of the proposed technique is confirmed by Finite Element Method(FEM) and its dynamic analysis is carried out from the coupling of the electrical circuit equation and mechanical kinetic equation.

• Journal of Korean Society on Water Environment
• /
• v.24 no.6
• /
• pp.773-783
• /
• 2008

In this paper, data collected from 22 different rural watersheds during stormflow conditions were analyzed. Those watersheds consisted of forest and cultivated land. EMC data analysis indicates that as agricultural land use increases, EMC values of TSS, COD and TN clearly tends to increase, but TP does not show a significant increase. Pattern of the pollutographs mostly has a similarity in hydrograph shape except nitrogen which inherently shows a variability and complication. The fraction of soluble reactive-P to TP increases as cultivated land use increases while mobile-nitrogen portion was higher in the runoff from forested watersheds than agricultural areas. During stormflow, pollutograph of the nitrogen was determined mainly by change in Particle-TKN as other pollutants but its effect is thought to be masked by decrease of dissolved form of nitrogen due to the dilution.

• Korean Journal of Materials Research
• /
• v.10 no.8
• /
• pp.551-557
• /
• 2000

Cu-based leadframe sheets were oxidized ic a hot alkaline solution to black-oxide layer on the surface and molded with epoxy molding compound(EMC), and finally machined to form sandwiched double-cantilever beam(SDCB) and sandwiched Brazil-nut(SBN)specimers to measure the adhesion strength of leadframe-EMC interface. The SDCB and the SBN specimens were designed to measure the adhesion strength in terms fracture toughness under puasi-mode I and mixed mode loadinf, respectively. After the tests, fracture surfaces were analyzed paths were observed in the SDCB-tested speciments, failure paths varied with crack speed and loading conditions.

• Journal of Korean Society on Water Environment
• /
• v.21 no.4
• /
• pp.385-392
• /
• 2005

The control of nonpoint source pollution is essentially needed to successfully perform the Total Maximum Daily Load program. Of the various land uses in the nonpoint source, the paved areas such as a parking lot and a bridge are stormwater intensive land uses because of high imperviousness and high pollutant mass emissions. This research was performed to understand the magnitude and nature of the stormwater emissions with the purposes of quantifying stormwater pollutant concentrations and mass emission rates from a parking lot and a bridge. Two monitoring sites in Kongju city were equipped with an automatic rainfall gages and an automatic flow meter for accumulating the data such as rainfall, water quality and runoff flow rates. This paper will summarize the metal concentration changes during the storm duration and metal EMCs to characterize the concentration profiles in a parking lot and a bridge. Also a new concept, dynamic EMC, will be proposed to find the relationship between EMC and first flush effect. It can be used to determine the economical treatment criteria in best management practices.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.23 no.5
• /
• pp.41-46
• /
• 2023

It is very important to meet the maximum detection range in a radar system. In order to meet the maximum detection Range, the sensitivity of the received signal of the radar system must be high. In addition, the dynamic range should be wide in the radar signal processing board. To meet these requirements, the signal processing board must be designed to be robust against external and internal noise. In particular, a design is required to minimize the effect of noise generated by various switching circuits inside the board on the received radar signal. In this paper, we derive the requirements of the signal processor board to meet the radar system performance and describe the design to meet the derived requirements. In addition, the EMC design to minimize the influence of noise input from the outside or generated from the inside is described. Confirm the secured performance through the test of the manufactured board.

• Journal of the Korean Chemical Society
• /
• v.54 no.5
• /
• pp.594-602
• /
• 2010

Since the requirement of the high density integration and thin package technique of semiconductor have been increasing, the main package type of semiconductor will be a chip scale package (CSP). The changes of diffusion coefficient and moisture content ratio of epoxy resin systems according to the change of liquid type epoxy resin and fillers for CSP applications were investigated. The epoxy resins used in this study are RE-304S, RE310S, and HP-4032D, and Kayahard MCD as hardener and 2-methylimidazole as catalyst were used in these epoxy resin systems. The micro-sized and nano-sized spherical type fused silica as filler were used in order to study the moisture absorption properties of these epoxy molding compound (EMC) according to the change of filler size. The temperature of glass transition (Tg) of these EMC was measured using Dynamic Scanning Calorimeter (DSC), and the moisture absorption properties of these EMC according to the change of time were observed at $85^{\circ}C$ and 85% relative humidity condition using a thermo-hygrostat. The diffusion coefficients in these EMC were calculated in terms of modified Crank equation based on Ficks' law. An increase of diffusion coefficient and maximum moisture absorption ratio with Tg in these systems without filler can be observed, which are attributed to the increase of free volume with Tg. In the EMC with filler, the changes of Tg and maximum moisture absorption ratio with the filler content can be hardly observed, however, the diffusion coefficients of these systems with filler content show the outstanding changes according to the filler size. The diffusion via free volume is dominant in the EMC with micro-sized filler; however, the diffusion with the interaction of absorption according the increase of the filler surface area is dominant in the EMC with nano-sized filler.