• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.359-359
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• 2000

Generally, level control in the steam generator of a nuclear power plant is difficulty process control, because the low power operating can lead nonminimum phase characteristics(swell and shrink phenomenon) and flow measurement are unreliable and nonlinear characteristics. This paper presents a framework for solving this problem based on the constrained linear model predictive control and introduces the design of method for the level of the controller in the entire operating power of the steam generator, and compares with conventional PI controller.

• Journal of Korea Water Resources Association
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• v.55 no.10
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• pp.835-841
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• 2022

The water level of the dam reservoir is an important data in the operation of the dam. reservoir storage can be calculated by using water levels or prepared for disasters such as drought and floods. However, the water level is measured near the dam, making it difficult to represent a reservoir with a large area, and there is a high possibility that the water surface will be distorted due to discharge. Furthermore, the results of the survey showed that the water level of the reservoir is irregular rather than constant, and the water level of the reservoir is repeatedly falling and rising by section. In order to calculate such a complex and irregular representative water level, the water level observation density of the reservoir must be increased. In this study, we tried to derive the optimum water level observation density for Hwacheon Dam. A reasonable water level measurement density was derived by investigating the water level elevation of the reservoir and statistically analyzing it. The observation density may vary depending on the size of the reservoir, so the same analysis was conducted on the Goesan Dam and Boseonggang Dam. According to the results, four Hwacheon dams, three Goesan dams, and seven Boseong River dams are needed for observation density.

• Economic and Environmental Geology
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• v.29 no.1
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• pp.21-24
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• 1996

Inductively coupled plasma atomic emission spectrophotometer (ICP/AES) is a versatile modern instruments for the multi-element analysis, but quantitative analysis using ICP/AES with normal pneumatic nebulizer is not applicable for the measurement of elemental concentrations in water down to the drinkining water standard level except a few elements because of poor detection limits. However, the detection limit can be lowered enough to measure drinking water standard, if ultrasonic nebulizer and/or hydride vapor generator is attached. This method is tested with groundwater samples from Tajeon area. It is confirmed that the elemental concentrations in these samples are within the limit of drinking water standard for the most elements. However, uranium concentration is very high in some samples compared with the concentrations suggested by Environmental Protection Agency of U.S.A. There is no standard concentration level to this element in Korea and it should be prepared immediately.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.5
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• pp.464-471
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• 2019

The acoustic power is a major acoustical characteristic of an underwater vehicle and could be measured in a reverberant water tank. In order to obtain accurate measurement results, the acoustic field formed by the sound source should be investigated quantitatively in the reverberant water tank. In this research, the acoustic field of a reverberant water tank containing an underwater sound source has been analyzed by using an acoustic radiosity method one of the numerical analysis methods suitable for the acoustic analysis of the highly diffused space. The source level of the underwater sound source and acoustical properties of the water tank input to the numerical analysis have been estimated by applying the reverberant tank plot method through a preliminary experiment result. The comparison of the numerical analysis result with that of the experiment has verified the accuracy of the acoustic radiosity method.

• Journal of Korean Society on Water Environment
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• v.33 no.2
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• pp.130-139
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• 2017

With the need to evaluate accuracy of real-time measurement of cyanobacterial fluorescence to determine cyanobacterial blooms, this research examined 357 paired data (2013-2016) comprising both microscopic toxic cyanobacterial cell counts and concurrent real-time cyanobacterial concentrations at 2 sites (YS1 and YS2) in Yeongsan river. The increase in real-time cyanobacterial concentration was closely associated with the exceedance of 5,000 cyanobacterial cells/ml (odds ratio [OR] 1.07, 95% confidence interval [CI] 1.03-1.12) and 10,000 cells/ml (OR 1.08, 95% CI 1.04-1.12) at YS2 site. The area under the receiver operating characteristic (ROC) curve for the real-time cyanobacterial measurement at the YS2 site was 0.93, which indicates the measurement provides a high accurate detection of cyanobacterial blooms. On the ROC curve, the early alert levels of real-time cyanobacteria ranging $16-23{\mu}g$ chl-a/L would produce acceptable sensitivity of 79% and specificities greater than 90%. The real-time fluorescence measurement was found to be an accurate indicator of cyanobacteria and can serve as a tool for detecting toxic cyanobacterial bloom events in Youngsan river.

• Journal of the Korean GEO-environmental Society
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• v.19 no.1
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• pp.25-30
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• 2018

Conventional monitoring method is used for evaluation of the reservoir and levee at the highest height sections. In recent years, automated measurement technology has been developed, and the measurement results are transmitted, collected and stored in real time into management office. Despite the development of real time monitoring technology, the measurement results are not used directly or indirectly with facility management at real time. Recently, as wireless sensor network measurement technology has been developed based on internet of things, this study proposed a real - time measurement and evaluation system based on wireless sensor network technology in the reservoir structure. As a result of the seepage analysis for the application, it was confirmed that the volumetric water content changes together with the change of the seepage line inside the embankment body according to the change of the water level of the embankment. In other words, the applicability of the measurement system with the volumetric water ratio set as the sensor node was verified.

• Herbal Formula Science
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• v.14 no.2
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• pp.57-66
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• 2006

Objectives : The objective of this study is to observe the effect of Saryuktangkamibang, Saryuktang with Liriopis Tuber, Lycii Fructus, Schizandrae Fructus, and Bombyx Batryticatus, on the experimental diabetes. Methods : In order to induce diabetes experimentally, injected streptozotocin to the vein in the tail of rats and then treated oral administration of Saryuktangkamibang water extracts. In the measurement of the variation levels of glucose, ALP, creatinine, and BUN concentration for each concentration levels for serum (0.2g/100g, 0.4g/l00g, 0.6g/100g), concentration level of glucose significantly decreased in 0.4g/l00g concentration level of Saryuktangkamibang. With this 0.4g/l00g concentration level of Saryuktangkamibang, the following conclusion was derived from the measurement of the serum levels of glucose. ALP, AST, ALT, creatinine, and BUN concentration for the injection of each 4th, 11th, and 18th day. Results : 1. In the measurement for each concentrations, the glucose concentration level in the serum significantly decreased on the 9th day in the Saryuktangkamibang-dosed group. 2. The creatinine and BUN concentration level in the serum significantly decreased on the 9th day in the Saryuktangkamibang-dosed group to which 0.6g/100g injected. 3. In the measurement for each dosage dates, the glucose concentration level in the serum significantly decreased on the 11th day in the Saryuktangkamibang-dosed group to which 0.6g/100g injected. 4. The AST concentration level in the serum significantly decreased on the 11th day in the Saryuktangkamibang-dosed group. Conclusion : Saryuktangkamibang, Saruktang with Liriopis Tuber, Lycii Fructus, Schizandrae Fructus, and Bombyx Batryticatus, has an effect of hypoglycemia, with no hepato-renal dysfunction. For the experimental results above, in that nephrotoxicity significantly decreased on the 0.6g/100g concentration, another research such as study for effect in other ranges and study for effect of dosage term except the concentration range of this study is necessary. Also dosage of appropriate concentration of Saryuktangkamibang is thought to provide valuable aid to cure on diabetes.

• Korean Journal of Remote Sensing
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• v.35 no.3
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• pp.389-400
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• 2019

Level meters are non-invasively capable of measuring the level of the medium, and a growing variety of level meters are being used in the industry in connection with safety and maintenance. The level meter can be measured according to various kinds of medium such as solid medium such as coal, flour, rice and liquid medium such as water and petroleum. In order to reduce the error depending on the medium, the measurement using the Doppler Effect can compensate the measurement error, However, the number of signal processing steps is increased, the operation speed is further increased, the hardware complexity increases, and a high cost structure is required. In this paper, we propose a method to improve the signal processing operation structure of the remote measurement level meter to reduce the amount of computation and the resource usage of the required FPGA.

• Journal of The Korean Society of Agricultural Engineers
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• v.53 no.6
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• pp.7-16
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• 2011

This study discussed the applicability of satellite SAR (Synthetic Aperture Radar) imagery with regard to reservoir monitoring, and tried the extraction of reservoir storage from multi-temporal C-band RADARSAT-1 SAR backscattering images of Yedang and Goongpyeong agricultural reservoirs, acquired from May to October 2005. SAR technology has been advanced as a complementary and alternative approach to optical remote sensing and in-situ measurement. Water bodies in SAR imagery represent low brightness induced by low backscattering, and reservoir storage can be derived from the backscatter contrast with the level-area-volume relationship of each reservoir. The threshold segmentation over the routine preprocessing of SAR images such as speckle reduction and low-pass filtering concluded a significant correlation between the SAR-derived reservoir storage and the observation record in spite of the considerable disagreement. The result showed up critical limitations for adopting SAR data to reservoir monitoring as follows: the inappropriate specifications of SAR data, the unreliable rating curve of reservoir, the lack of climatic information such as wind and precipitation, the interruption of inside and neighboring land cover, and so on. Furthermore, better accuracy of SAR-based reservoir monitoring could be expected through different alternatives such as multi-sensor image fusion, water level measurement with altimeters or interferometry, etc.

• Journal of Korean Elementary Science Education
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• v.32 no.2
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• pp.139-158
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• 2013

This study investigated elementary students' (grade 4~6) learning progressions for water cycling drawn from iterative assessments using ordered multiple-choice (OMC) items. An assessment system, which consisted of construct map, item design, outcome space, and measurement model, was employed in this study to examine children's learning progressions. At the first stage of the assessment system, a construct map was designed on which children's conceptual understandings from naive to most sophisticated were represented. At the item design stage, 8 OMC items were drawn from the construct map. Each item option of the OMC items was scored from 0 to 3 according to its level of understanding at the stage of outcome space. As a measurement model, Rasch model, a branch of item response theory, was applied to interpreting the outcomes of the OMC items. This cycle of assessment system was furtherly implemented iteratively in order to elaborate on the first version of water cycling learning progression. In conclusion, children's understanding of water cycling could be described in two aspects: water distribution and water movement. We identified children's conjectural developmental pathways about water cycling existed from superficial and naive accounts to more complex and abstract accounts.