• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.133-133
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• 2021

The performance of radar Quantitative Precipitation Estimation (QPE) using Long Short-Term Memory (LSTM) networks in hydrological applications depends on either the quality of data or the three-dimensional CAPPI structure from the weather radar. While radar data quality is controlled and enhanced by the more and more modern radar systems, the effect of CAPPI structure still has not yet fully investigated. In this study, three typical and important types of CAPPI structure including inverse-pyramid, cubic of grids 3x3, cubic of grids 4x4 are investigated to evaluate the effect of CAPPI structures on the performance of radar QPE using LSTM networks. The investigation results figure out that the cubic of grids 4x4 of CAPPI structure shows the best performance in rainfall estimation using the LSTM networks approach. This study give us the precious experiences in radar QPE works applying LSTM networks approach in particular and deep-learning approach in general.

• YAKHAK HOEJI
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• v.52 no.6
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• pp.419-425
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• 2008

A qualitative and quantitative analytical method was developed for detection of methamphetamine (MA) and its main metabolite amphetamine (AM) in oral fluid. Oral fluids of eleven drug abusers were provided by Police, specimens were collected by stimulation with a cotton swab treated with 20 mg of citric acid ($Salivette^{(R)}$; Sarstedt, USA). As the preliminary test, oral fluid samples were screened for amphetamines by Fluorescence Polarization Immunoassay (TDxFLx, Abbott Co.). Extraction for MA was performed using solid-phase extraction (SPE) by $RapidTrace^{TM}$ (Zymark, USA) with mixed mode cation exchange cartridge, CLEAN $SCREEN^{(R)}$ (130 mg/3 ml, UCT) after dilution with phosphate buffer. Samples were evaporated and derivatized by pentafluoropropionic acid anhydride (PFPA). Quantitation of MA and AM was performed by gas chromatography-mass spectrometry (GC-MS) using selective ion monitoring (SIM), the quantitation ions were m/z 204 (MA), 208 (MA-$D_5$), 190 (AM) and 194 (AM-$D_5$). The selectivity, linearity of calibration, limit of detection (LOD) and quantification (LOQ) within- and between day precision, accuracy and recoveries were examined as parts of the method validation. All oral fluid samples gave positive results to immunoassay for MA (cut-off level, 50 ng/ml as d-amphetamine). Concentrations of MA and AM by GC-MS in eleven samples were ranged 104.2${\sim}$4603.3 ng/ml and 32.4${\sim}$268.6 ng/ml, respectively. Extracted calibration curves of MA and AM were linear over the two concentration range of 1${\sim}$100 and 50${\sim}$1000 ng/ml with correlation coefficient of above 0.999. LOQ of MA and AM was 1 and 3 ng/ml, respectively. The intraand inter-day run precisions (CV) for MA and AM were less than 10%, and the accuracies (bias) for MA and AM were also less than 10% at the two different concentrations 5 and 100 ng/ml at low calibration range, 50 and 1000 ng/ml at high calibration range. The absolute recoveries of MA and AM at low and high calibration ranges were more than 82% and 75%, respectively. In this study the qualitative and quantitative analytical method of MA in oral fluid was established. Oral fluid testing may detect drug use in past hours because of its shorter detection window than urine, and be useful in post-accident situations. So oral fluids will be most useful for testing drug abuse in the driving under the influence of drug (DUID) as the alternative specimens of urine.

• Journal of Environmental Health Sciences
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• v.31 no.2 s.83
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• pp.134-146
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• 2005

Environmental monitoring system has been adopted and supplemented as inspection measures for the quantitative and qualitative changes of environmental impact assessment (EIA). This study compares the results of environmental impact assessment with the results of post-environmental investigation using a correction and principal component analysis (PCA) in the housing development project. Correlation analysis showed that most of air quality variables including TSP, $PM_{10},\;NO_2$, CO were linearly correlated with each other in the environmental impact assessment and the post-environmental investigation. In the water quality, pH and BOD were well correlated with the DO and SS, respectively. As a result of correlation analysis in the noise and vibration, noise in day and night and vibration in day and night were related to each other between EIA and the post-environmental investigation. From the results of analysis of soil, Cu with Cd, Cu with Pb, and Cd with Pb were related to each other in EIA. Principal component analysis (PCA) showed a powerful pattern recognition that had attempted to explain the variance of a large dataset of inter-correlated variable with a smaller set of independent variables (principal components). Principal component (PC1) and principal component (PC2) were obtained with eigenvalues> 1 summing almost $90\%$ of the total variance in the all of the items(air, water, noise, vibration and soil) in EIA and post-environmental investigation.

• Journal of Power Electronics
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• v.9 no.6
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• pp.949-959
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• 2009

This paper presents a systematic investigation of the fault-mode behaviors of matrix converter systems. Knowledge about converter behaviors after fault occurrence is important from the standpoint of reliable system design, protection and fault-tolerant control. Converter behaviors have been, in detail, examined with both qualitative and quantitative approaches for key fault types, such as switch open-circuited faults and switch short-circuited faults. Investigating the fault-mode behaviors of matrix converters reveals that converter operation with switch short-circuited faults leads to overvoltage stresses as well as overcurrent stresses on other healthy switching components. On the other hand, switch open-circuited faults only result in overvoltage to other switching components. This study can be used to predict fault-mode converter behaviors and determine additional stresses on remaining power circuit components under fault-mode operations.

• Journal of The Korean Society of Agricultural Engineers
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• v.48 no.3
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• pp.11-20
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• 2006

In this study, the actual water management were investigated and analyzed on site for effective use of the paddy irrigation water. And this study is tried to analyze the difference between simulated irrigation water according to current design method and actual water supply in experimental reservoirs. The reservoirs in Idong, Yongdeok and Misan, which are managed by Korea Rural Community & Agriculture Corporation, were selected fur field investigation. The purpose of this study is to suggest an improved method for irrigation water calculation through quantitative and periodical analysis considering the difference between design and actual field condition.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1024-1028
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• 2009

Government imposed a duty to perform feasibility investigation on huge development projects which cost are higher than 50 million dollars on May 1999. This is to prevent waste of money occur from lack of review on huge public projects and raise the efficiency of government budget. Although maintenance and managing analysis method for public infrastructures are developed and proposed by other institutions as Korea Infrastructure Safety & Technology Corporation but it is not well applied on the aspect of the railway fixed time and costumer costs. Therefore a good point of quantitative and qualitative reference which fits railway character is need and following guidelines from the phase of feasibility study are need to prevent governments budget waste.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.286-289
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• 2009

This paper deals with the experimental investigation of the steel cord straightening during the stranding process. The over-twisting and roller straightening process are essential to improve the product quality during the stranding process. To investigate the effectiveness of two processes, four experimental cases are constructed according to the use of an over-twister and two roller straighteners. Three assessment items, such as the residual torsion, the arc-height and the preforming ratio, are measured in each experimental case for the quantitative evaluation of a steel cord. The steel cord shape is also measured to investigate the variation of the straightness efficiently after passing through each process. Finally, the effectiveness of the over-twisting and the roller straightening process is explained based on the experimental results.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.169.1-169.1
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• 2003

This study was designed to compare the results and concentraions of methamphetamine (MA) and its metabolite amphetamine (AP) in head hair and hair collected from different parts of the body (axullae, pubis, and leg). Hair of subjects (N=15) suspected for MA abuse was simultaneously collected. (omitted)

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.112.1-112.1
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• 2003

The qualitative and quantitative analysis of MDMA and MDA in hair samples by GC/MS were reported. Hairs were collected from subjects aged 22-37 years, who were suspected of abusing MDMA. After washing with methanol, hair samples were cut into small pieces, extracted with methanol containing 1 percent hydrochloric acid for 20th, and the solution was evaporated. MDMA or MDA in the extract were determined by GC/MS using selected ion monitoring after derivatization with trifluoroacetic anhydride. (omitted)

• Journal of the Korean Society of Marine Environment & Safety
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• v.6 no.1
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• pp.69-76
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• 2000

Bubble boom may be a good alternative for the prevention of oil spill pollution due to its easy deployment and clean post-process tasks. The present work is focused on the experimental investigation of air bubble movement for the bubble boom by visualization and quantitative PIV measurements. Bubble plume was generated by adjusting the pressure of pressure vessel ranging 6.7 kpa to 14.7 kpa. The results showed at lower inlet velocity and higher supply air flow rate that bubble boom maintained its containing capability reasonably well up to the maximum containing limit.