• Journal of Korean Society of Water and Wastewater
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• v.26 no.6
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• pp.815-823
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• 2012

Non-point source pollutants in down stream of Nakdong river were simulated by SWAT. GIS was utilized to make input data of SWAT such as landuse pattern and soil. Meteorological data of 2007 and 2009 were applied for the calibration and validation of runoff in SWAT. It was difficult to calibrate and validate the runoff and nutrient results since a study area was influenced by the tidal effects. Jindong site was selected to escape from the bias of runoff simulation in the coastal area. $R^2$ values of calibration and validation were 0.8 and 0.79. However, $R^2$ values of water qualities were very low level in comparison to runoff. These resulted from the concentration scale of water qualities such as BOD, T-N and T-P. Additionally, tidal influence could effected on the measurements of nutrients. The simulated annual averages and patterns of BOD, T-N and T-P in SWAT were similar to the measurement data. 80 ~ 96 % of nonpoint source pollutants at Nakbon M site were released from April to August of 2009. The ratio of T-N and T-P from nonpoint source were above 50 % during the rainy season.

• Journal of the Korean Society of Industry Convergence
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• v.6 no.4
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• pp.361-366
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• 2003

Most sensor array signal processing methods for multiple source localization require knowledge of the correct shape of array(the correct positions of sensors that consist array), because sensor position uncertainty can severely degrade the performance of array signal processing. In particular, it is assumed that the correct positions of the sensors are known, but the known positions may not represent the true sensor positions. Various algorithms have been proposed for 2-D sensor array shape calibration in far field environment. However, they are not available in near field. In this paper, 3-D sensor array shape calibration algorithm is proposed, which is available in near field.

• Journal of Radiation Protection and Research
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• v.41 no.3
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• pp.211-215
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• 2016

Background: The moderated neutron calibration fields using $^{241}Am$-Be sources and a graphite moderator have been constructed at the Facility of Radiation Standard (FRS) in the Japan Atomic Energy Agency (JAEA). Materials and Methods: The neutron spectra of the fields were evaluated by the Monte-Carlo calculations and measurements using the Bonner Multi-sphere Spectrometer. Results and Discussion: The fields have continuous neutron spectra from several MeV to thermal neutron energy, with fluence-averaged energies of 0.84 MeV and 0.60 MeV. Reference values of fluence rates and ambient/personal dose equivalent rates were determined from neutron spectra by measurements. Conclusion: Currently, the fields are available for calibration or performance test of neutron measuring instruments.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.413-416
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• 1998

Sensitivity and calibration considerations are most important in the design and implementation of real control systems. Ideally parameter changes due to various causes should not appreciably affect the system's performances. But all the values of physical components of the plants and controllers as well as the relevant environmental conditions change in time, thus the output performance can be deteriorated during the operating span of the system. Naturally the duty of calibration or the prevention of performance deterioration due to excessive component sensitivity should be provided to the control system. In this paper, we propose a digital controller which has the capability of calibration and gain adjustment as well as the execution of control law. Specifically the problems of gain adjustment and offset calibration in the light source and CdS sensor module for position measurement in a flexible link system are considerably resolved. The parameters of measurement module are prone to change due to environmental brightness conditions resulting in poor steady state performance of the overall control system. Thus a proper method is necessary to provide correction to the changed values of gain and offset in the position measurement module. The proposed controller, whenever necessary, measures the open-loop characteristics, andthen calculates the offset and sensor gain correction values based on the prepared standard measurements. It is applied to the control of a flexible link system with the gain and offset calibration porblems in the light sensor module for position to show the applicability.

• ETRI Journal
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• v.38 no.3
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• pp.551-559
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• 2016

In this paper, we propose a hybrid sensor calibration scheme for mobile crowdsensing applications. As the number of newly produced mobile devices containing embedded sensors continues to rise, the potential to use mobile devices as a sensor data source increases. However, because mobile device sensors are generally of a lower performance and cost than dedicated sensors, sensor calibration is crucial. To enable more accurate measurements of natural phenomena through the use of mobile device sensors, we propose a hybrid sensor calibration scheme for such sensors; the scheme makes use of mobile device sensors and existing sensing infrastructure, such as weather stations, to obtain dense data. Simulation results show that the proposed scheme supports low mean square errors. As a practical application of our proposed scheme, we built a temperature map of a city using six mobile phone sensors and six reference sensors. Thanks to the mobility of the sensors and the proposed scheme, our map presents more detailed information than infrastructure-based measurements.

• Fire Science and Engineering
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• v.32 no.4
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• pp.1-6
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• 2018

As a preliminary study to quantify the measurement uncertainty of the Schmidt-Boelter type heat flux gauge, the present study has been conducted to evaluate the measurement error due to the calibration constant supported by manufacturer. Calibrations of heat flux gauges are performed at NIST Fire Research Division using a calibration facility with heat source of a 2000 W halogen-tungsten filament lamp and the calibration constant is obtained by comparing the response of the reference and a standard heat flux gauge at the same irradiance conditions. Calibration for heat flux gauges made by three different manufacturers is compared with their factory calibration constant. Relative error due to fluctuation of output signal from heat flux gauges does not exceed 1% of the mean value and the relative error between calibration of this study and factory calibration constant ranged from 1.5% to 14.3%. The present study shows that a continuous and periodic calibration is necessary for accurate heat flux measurement.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.12
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• pp.109-117
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• 2015

In this paper, we proposed error-reducing method to source or measure a current or voltage for LED in the I-V characteristic analysis system using a digital signal processor (DSP). this method has the advantage of reducing a non-linear circuit error and random error. random error can be reduced using recursive averaging technique and non-linear circuit error can be reduced using 2rd polynomial regression calibration parameters fitting with measured sample data. it corrects measured error of IR, VR, VF1, VF2, VF3 of LED using calibration parameters. experimental results show that can be performed with about 0.017~0.043% accuracy.

• Journal of Korean Society on Water Environment
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• v.31 no.5
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• pp.507-522
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• 2015

In this study, some of the model verification results of STREAM (Spatio-Temporal River-basin Ecohydrology Analysis Model), a newly-developed hybrid watershed model, are presented for the runoff processes of nonpoint source pollution. For verification study of STREAM, the model was applied to a test watershed and a sensitivity analysis was also carried out for selected parameters. STREAM was applied to the Mankyung River Watershed to review the applicability of the model in the course of model calibration and validation against the stream flow discharge, suspended sediment discharge and some water quality items (TOC, TN, TP) measured at the watershed outlet. The model setup, simulation and data I/O modules worked as designed and both of the calibration and validation results showed good agreement between the simulated and the measured data sets: NSE over 0.7 and $R^2$ greater than 0.8. The simulation results also include the spatial distribution of runoff processes and watershed mass balance at the watershed scale. Additionally, the irrigation process of the model was examined in detail at reservoirs and paddy fields.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.73.2-73.2
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• 2016

We present the results of KaVA SgrA* observation together with Takahagi(32m), Yamaguchi(32m) and Nobeyama(45m) telescopes at 22 and 43GHz, respectively. In early 2014, G2 cloud was expected to encounter with SgrA* and to make a significant flux variation, but it has not been measured yet. So it's worth to check our amplitude calibration method to confirm if we have a missing flux caused by uncertainty in measuring it. We have tested both a standard method using system noise temperature(Tsys) with antenna gain information, and a template method in order to calibrate antenna gain using nearby maser source. As a result, we found that the latter method is useful for antennas which have inaccurate gain information or poor Tsys measurements, and is especially effective for sources at low elevation like SgrA*. In addition, the comparison shows that the amplitude calibration by standard method can be improved up to 10% with a correction factor using a template method. This result implies we can get more accurate flux from a standard method when any maser source not exists around target.

• Nuclear Engineering and Technology
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• v.53 no.11
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• pp.3717-3722
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• 2021

In this study, the recovery rates of the dissolution method for radioactivity analysis of expandable polystyrene (EPS) with a liquid scintillation counter (LSC) using tetrahydrofuran (THF), toluene, and acetone as solvents were estimated. The detection efficiency calibration curve for each solvent was derived. Two methods-the volumetric ratio method and the quenching agent method-were used to prepare quench source sets, and calibration curves were derived by linking the data from the two quench source sets. The R² value of the calibration curve for THF was found to be 0.984. The relationship between the mass of dissolved EPS and the quench level was estimated: the quench level increased as the mass of dissolved EPS increased. Premix and postmix dissolution methods were tested. The recovery rates using THF with the premix method were 84.9 ± 0.9% and 96.5 ± 1.5% for ³H and ¹⁴C, respectively. Furthermore, the stability of the recovery rate over time when using THF was evaluated. The dissolution method with the premixed solution exhibited a more stable recovery rate over time. The dissolution methods were found to be applicable for analysis using LSC, and THF was found to be the most suitable solvent for the proposed method.