• Korean Journal of Environmental Agriculture
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• v.37 no.3
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• pp.189-196
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• 2018

BACKGROUND: Water quality management of river requires quantification of pollutant loads and implementation of measures through monitoring study, but it requires labour and costs. Therefore, many researchers are performing nonpoint source pollution analysis using computer models. However, calibration of model parameters needs observed data. Nitrogen concentration in rainfall is one of the factors to be considered when estimating the pollutant loads through application of the nonpoint source pollution model, but the default value provided by the model is used when there are no observed data. Therefore, this study aims to provide the representative nitrogen concentration of the rainfall for the administrative district ensuring rational modeling and reliable results. METHODS AND RESULTS: In this study, rainfall monitoring data from June 2015 to December 2017 were used to determine the nitrogen concentration in rainfall for each administrative district. Range of the $NO_3{^-}$ and $NH_4{^+}$ concentrations were 0.41~6.05 mg/L, 0.39~2.27 mg/L, respectively, and T-N concentration was 0.80~7.71 mg/L. Furthermore, the national average of T-N concentration in this study was $2.84{\pm}1.42mg/L$, which was similar to the national average of T-N 3.03 mg/L presented by the Ministry of Environment in 2015. Therefore, the nitrogen concentrations suggested in this study can be considered to be resonable values. CONCLUSION: The nitrogen concentrations estimated in this study showed regional differences. Therefore, when estimating the pollutant loads through application of the nonpoint source pollution model, resonable parameter estimation of nitrogen concentration in rainfall is possible by reflecting the regional characteristics.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.2
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• pp.270-275
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• 2012

This paper presents a portable and compact optical device which can conveniently be used to perform a functional analysis of human liver function. The proposed system employed red/green LEDs, as a light source, and CMOS image sensor, which is commonly used in cellular phones. With this system, several blood serum samples have been evaluated for liver functional analysis by measuring light absorption level through the blood serum samples depending on aspartate aminotransferase (AST), alanine aminotransferase (ALT), and total bilirubin concentration. The light absorption through the blood serum samples containing AST, ALT, or total bilirubin can provide their concentrations. The green light absorption is more sensitive to the concentration of AST or ALT, and the red light absorption is more sensitive to the total bilirubuin concentration. Additional calibration steps were performed by using a MATLAB program in order to eliminate the light scattering effects from the extraneous particles existing in each blood serum sample. From the blind test, three standard light intensity curves through each enzyme have been obtained and the enzyme concentration values have been compared to those obtained from a commercially available biochemistry analyzer (Toshiba 200 FR). The average percent difference in the obtained concentrations from two systems for AST, ALT, and total bilirubin concentration came out to be 7.79%, 7.98%. and 7.56%, respectively, with the adjusted coefficient of determination (R2) higher than 0.98. This system can possibly lead to a low-cost and simple system that can be used as a point-of-care (POC) system in a condition without advanced equipments.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.3
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• pp.891-900
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• 1996

The vision sensor which is based on the optical triangulation theory with the laser as an auxiliary light source can detect not only the seam position but the shape of seam. In this study, a vision sensor using the scanning laser beam was investigated. To design the vision sensor which considers the reflectivity of the sensing object and satisfies the desired resolution and measuring range, the equation of the focused laser beam which has a Gaussian irradiance profile was firstly formulated, Secondly, the image formaing sequence, and thirdly the relation between the displacement in the measuring surface and the displacement in the camera plane was formulated. Therefore, the focused beam diameter in the measuring range could be determined and the influence of the relative location between the laser and camera plane could be estimated. The measuring range and the resolution of the vision sensor which was based on the Scheimpflug's condition could also be calculated. From the results mentioned above a vision sensor was developed, and an adequate calibration technique was proposed. The image processing algorithm which and recognize the center of joint and its shape informaitons was investigated. Using the developed vision sensor and image processing algorithm, the shape informations was investigated. Using the developed vision sensor and image processing algorithm, the shape informations of the vee-, butt- and lap joint were extracted.

• Bulletin of the Korean Chemical Society
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• v.34 no.9
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• pp.2760-2764
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• 2013

Geniposide is a biologically active ingredient of gardenia fruit. A liquid chromatography-tandem mass spectrometric method was developed and validated for the determination of geniposide in rat plasma. The plasma samples were pretreated by solid-phase extraction and introduced into a BDS Hypersil $C_{18}$ column ($50{\times}2.1mm$, $5{\mu}m$) for chromatographic separation. The mobile phase consisted of 0.1% formic acid and 0.1% formic acid in acetonitrile, and gradient elution was performed at a flow rate of 0.25 mL/min. For mass spectrometric detection, multiple reaction monitoring was performed via an electrospray ionization source in positive mode. The calibration curve for geniposide was linear ($r^2=0.997$) in the concentration range of $0.005-1{\mu}g/mL$. The intra- and inter-day accuracies and precisions fulfilled the required criteria (${\pm}15%$). The developed method was subsequently used for pharmacokinetic analysis of geniposide after oral administration to rats at a dose of 50 mg/kg. The mean maximum plasma concentration of geniposide was $0.68{\pm}0.29{\mu}g/mL$ at $0.44{\pm}0.13h$, and the mean area under the plasma concentration versus time curve was $1.46{\mu}g{\cdot}h/mL$.

• Journal of the Korean Association of Geographic Information Studies
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• v.8 no.2
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• pp.125-135
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• 2005

Generation and transport of nonpoint source pollution, especially sediment-associated pollutants, are profoundly influenced by hydrologic features of runoff. In order to identify pollutant export rates, hence, clear knowledge of rainfall-runoff relationship is a pre-requisition. In this study, performance of AnnAGNPS model was assessed based on the ability of the model to predict rainfall-runoff relationship. Three catchments, each under different nearly single land use, were simulated. From the results, it was found that the model was likely to produce better predictions for larger catchments than smaller catchments. Because of using the daily time scale, the model could not account for short durations less than 24 hours, especially high intensity events with multiple peak flow that significantly contribute to the generation and transport of pollutants. Since CN information for regional areas has not been built up, a careful selection of CN is needed to achieve accurate prediction of runoff volume. Storm distribution also found to be considered as an important calibration parameter for the hydrologic simulation.

• Journal of Korean Society on Water Environment
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• v.34 no.1
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• pp.33-45
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• 2018

In this study, we discussed the application of Watershed model and Load Duration Curves (LDC) in Total Water Load Management System. The Flow Duration Curves (FDC) and the LDC were generated using the results of the daily HSPF model and analyzed on monthly or yearly flow duration variability, and non-point pollutant discharge loads by entire flow conditions. As a result of the calibration and verification of the HSPF model, both the flow and the water quality were appropriately simulated. The simulated values were used to generate the Flow Duration Curve and the Load Duration Curve, and then the excess rate by entire flow conditions was analyzed. The point and non-point pollutant discharge loads for entire flow conditions were calculated. It is possible to evaluate the variability of water quality in specific flow duration through the curves reflecting the flow duration variability and to confirm the characteristics of the pollutant source. For a more scientific Total Water Load Management System, it is necessary to switch from a current system to a system that can take into account the entire flow conditions. For this, the application of the watershed model and load duration curve is considered to be the best alternative.

• Safety and Health at Work
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• v.7 no.4
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• pp.381-388
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• 2016

Background: Relationships among portable scanning mobility particle sizer (P-SMPS), condensation particle counter (CPC), and surface area monitor (SAM), which are different metric measurement devices, were investigated, and two widely used research grade (RG)-SMPSs were compared to harmonize the measurement protocols. Methods: Pearson correlation analysis was performed to compare the relation between P-SMPS, CPC, and SAM and two common RG-SMPS. Results: For laboratory and engineered nanoparticle (ENP) workplaces, correlation among devices showed good relationships. Correlation among devices was fair in unintended nanoparticle (UNP)-emitting workplaces. This is partly explained by the fact that shape of particles was not spherical, although calibration of sampling instruments was performed using spherical particles and the concentration was very high at the UNP workplaces to allow them to aggregate more easily. Chain-like particles were found by scanning electron microscope in UNP workplaces. The CPC or SAM could be used as an alternative instrument instead of SMPS at the ENP-handling workplaces. At the UNP workplaces, where concentration is high, real-time instruments should be used with caution. There are significant differences between the two SMPSs tested. TSI SMPS showed about 20% higher concentration than the Grimm SMPS in all workplaces. Conclusions: For nanoparticle measurement, CPC and SAM might be useful to find source of emission at laboratory and ENP workplaces instead of P-SMPS in the first stage. An SMPS is required to measure with high accuracy. Caution is necessary when comparing data from different nanoparticle measurement devices and RG-SMPSs.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.3
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• pp.10-16
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• 2004

In this paper the aeroacoustic characteristics of a helicopter main rotor system is measured by using a pair of scaled rotor blades. A low noise rotor test jig is developed for noise measurement and the rotational speed, thrust and torque are measured simultaneously in order to match the aerodynamic conditions with the full scale rotor. The accuracy of the force measurement device was checked through a calibration procedure. The measured thurst and torque with a 1.2m rotor are compared to the results of analytical prediction and showed that the thrust data at various rotational speed followed the prediction relatively well, but the torque data considered less accurate. It is also found that the background noise level of the test rig is sufficiently low, and the measured noise level from the rotor can be scaled with rotor tip speed. However, the Mach number dependancy and the directivity changes depend on the noise source characteristics.

• Korean Journal of Optics and Photonics
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• v.10 no.1
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• pp.21-26
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• 1999

The technique for calibrating standard particles larger than 1 $\mu$m by using an optical array sizing method has been established. The system consists of an optical microscope with transmission light source, a CCD camera, and a computer equipped with a frame grabber. The center distance between two spheres located at both ends of a row which consists of N spheres is measured in terms of pixel numbers, and divided by (N-1) to obtain the average pixel numbers per particle. This value is multiplied by length conversion constant, which has been determined in advance, to obtain the mean diameter of polystylene spheres. The length conversion constant is found from the microscopic image of calibrated standard stage micrometer plate. In order to reduce error in finding center positions of the scale and particles in the image, a software filter which dilates bright (or dark) object has been used. Spheres having nominal size of 1, 2, 3, 5, and 10$\mu$m were measured, and the maximum deviation of the measured mean diameter valus from their certified values was 0.7%. Standard particles which is larger than 1 $\mu$m can be calibrated by this method with measuredment uncertainy (k=2) lees than 1.53%.

• Journal of Korea Water Resources Association
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• v.37 no.12
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• pp.1009-1018
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• 2004

A systematic method using an optimal estimation algorithm is presented for simultaneous estimation of diffuse pollution distributed along a stream reach and model parameters for a stream water quality model. It was applied with the QVAL2E model to the South Han River for optimal estimation of kinetic constants and diffuse loads along the river. Initial calibration results for kinetic constants selected from a sensitivity analysis reveal that diffuse source inputs for nitrogen and phosphorus are essential to satisfy the system mass balance. Diffuse loads for total nitrogen and total phosphorus were estimated solving the expanded inverse problem. Comparison of kinetic constants estimated simultaneously with diffuse sources to those estimated without diffuse loads, suggests that diffuse sources must be included in the optimization not only for its own estimation but also for adequate estimation of the model parameters. Application of optimization method to river water quality modeling is discussed in terms of the sensitivity coefficient matrix structure.