• Atmosphere
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• v.24 no.3
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• pp.445-456
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• 2014

A real-time quality control system for meteorological data (air temperature, air pressure, relative humidity, wind speed, wind direction, and precipitation) measured by an integrated meteorological sensor has been developed based on comparison of quality control procedures for meteorological data that were developed by the World Meteorological Organization and the Korea Meteorological Administration (KMA), using time series and statistical analysis of a 12-year meteorological data set observed from 2000 to 2011 at the Incheon site in Korea. The quality control system includes missing value, physical limit, step, internal consistency, persistence, and climate range tests. Flags indicating good, doubtful, erroneous, not checked, or missing values were added to the raw data after the quality control procedure. The climate range test was applied to the monthly data for air temperature and pressure, and its threshold values were modified from ${\pm}2{\sigma}$ and ${\pm}3{\sigma}$ to ${\pm}3{\sigma}$ and ${\pm}6{\sigma}$, respectively, in order to consider extreme phenomena such as heat waves and typhoons. In addition, the threshold values of the step test for air temperature, air pressure, relative humidity, and wind speed were modified to $0.7^{\circ}C$, 0.4 hPa, 5.9%, and $4.6m\;s^{-1}$, respectively, through standard deviation analysis of step difference according to their averaging period. The modified quality control system was applied to the meteorological data observed by the Weather Information Service Engine in March 2014 and exhibited improved performance compared to the KMA procedures.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.437-441
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• 2001

This paper describes the construction of a circular polariscope. Generally, a circular polariscope contains four optical elements and a light source. The first element following the light source is called the polarizer. It converts the ordinary light into plane-polarized light. The second element is a quarter wave plate which converts the plane-polarized light into circularly polarized light. Following the quarter wave plate, a specimen made of transparent photoelastic material is located in a loading device. The second quarter wave plate is set and the last element is the analyzer. These polarizing elements, two quarter wave plates and two polarizing filters, were purchased from the USA. Frames and other structures for holding polarizing filters were machined and assembled to be rotated. Light box, which include four incandescent lamps and two sodium-vapor lamps, was made. In order to proof the function of the newly built polariscope, Tardy compensation test was applied to a rectangular shaped specimen made of poly-carbonate material (PSM1). The error of the fringe constant, which was measured by the newly built polariscope, was within 4.4 percent compared to the standard value of this material. It is possible to make a good quality of polariscope if accurate polarizing filters will be used.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.4
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• pp.151-159
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• 2015

In this study, we developed an automated contact-type thickness measurement machine that continuously and precisely measures the thickness of a PCB module product using multi-LVDT sensors. The system contains a measurement part to automatically measure the thickness in real time according to the set conditions with an alignment supply unit and unloading unit to separate OK and NG products. The sensors were calibrated before assembly in the measuring machine, and precision and accuracy performance tests were also performed to reduce uncertainty errors in the measurement machine. In the calibration test, the precision errors of the LVDT sensor were determined to be $1-3{\mu}m$ as 0.1% at the measuring range. A measurement error of 0.8 mm and 1.0 mm thickness test standards were found to be $1{\mu}m$ and $4{\mu}m$, and the standard deviations of two 1.0 mm products were measured as $14{\mu}m$ and $8{\mu}m$, respectively. In the measurement system analysis, the accuracies of test PCB standards were found to be $2{\mu}m$ and $3{\mu}m$, respectively. From the results of gage repeatability and reproducibility (R & R) crossed, we found that the machine is suitable for the measurement and process control in the mass production line as 7.92% of total gage R & R and in seven distinct categories. The maximum operating speed was limited at 13 pcs/min, showing a value good enough to measure.

• The Journal of Advanced Prosthodontics
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• v.11 no.2
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• pp.75-80
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• 2019

PURPOSE. The purpose of this study is to investigate the effects of aging and various risk factors on the oral environment and to analyze them in 3-dimensions. MATERIALS AND METHODS. A total of 800 patients were enrolled in this study, and subjects were divided into 4 groups by age-under 55, 56 - 65, 66 - 75, and over 76. Based on their most recent visit, the number of crowns, bridges, implants, and the remaining natural teeth were recorded. Smoking habits, along with presence of diabetes and hypertension, were surveyed, as risk factors were also set as a variable. Comparisons among the groups or within the groups were performed by independent t-test, and one-way and two-way ANOVA. Kruskal-Wallis test and Mann-Whitney U test were used for analysis. It was assumed to be statistically significant when P value is below .05. RESULTS. Changes in the number of crowns, bridges, implants, and the remaining natural teeth by age were statistically significant. When we examined the effect of risk factors on the change of variables with age, hypertension was found to affect the number of bridges. Diabetes and smoking were found to affect the number of the remaining natural teeth. The other variables were not statistically significant. CONCLUSION. Aging is considered to be an important variable affecting the change of oral environment. Among the risk factors, the presence of smoking habit and diabetes is thought to have a great influence on the change of the number of the remaining natural teeth.

• The Journal of Internal Korean Medicine
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• v.42 no.6
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• pp.1255-1268
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• 2021

Objectives: This study aimed to analyze the healthcare utilization behavior of patients visiting the department of Korean internal medicine in the Korean medicine hospital of Wonkwang University in Jeon-ju from July 2018 to June 2021. Methods: We retrospectively analyzed the medical records of 26,108 patients and sorted the data by period, month, visiting types, new or returning types, sex, and age group. IBM SPSS 26.0 and the R 4.05 'changepoint' package were used with various statistical methods, such as Independent t-test, Mann-Whitney test, Chi-square test, Simple regression analysis. The P-value was set at 0.05. Results and Conclusions: Females outnumbered males regardless of period, and the ratio of females fell after COVID-19. Regardless of visiting types, patients in their 50s, 60s, and 70s outrated any other age group. The average number of females among the returning patients decreased significantly after COVID-19, but did not in males. Outpatients under 10 and in their 10s decreased significantly after COVID-19, as did inpatients in their 40s and 60s. The average duration of hospitalization was extended significantly after COVID-19. The number of outpatients and inpatients decreased as time passed after COVID-19. We expect that the results of this study will be used as reference materials in analyzing the effects of COVID-19 on healthcare utilization.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.690-693
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• 2002

According to the growth of communication biz, embedded market rapidly developing in domestic and overseas. Embedded system can be used in various way such as wire and wireless communication equipment or information products. There are lots of developing performance applying speech recognition to embedded system, for instance, PDA, PCS, CDMA-2000 or IMT-2000. This study implement minimum memory of speech recognition engine and DB for apply real time embedded system. The implement measure of speech recognition equipment to fit on embedded system is like following. At first, DC element is removed from Input voice and then a compensation of high frequency was achieved by pre-emphasis with coefficients value, 0.97 and constitute division data as same size as 256 sample by lapped shift method. Through by Levinson - Durbin Algorithm, these data can get linear predictive coefficient and again, using Cepstrum - Transformer attain feature vectors. During HMM training, We used Baum-Welch reestimation Algorithm for each words training and can get the recognition result from executed likelihood method on each words. The used speech data is using 40 speech command data and 10 digits extracted form each 15 of male and female speaker spoken menu control command of Embedded system. Since, in many times, ARM CPU is adopted in embedded system, it's peformed porting the speech recognition engine on ARM core evaluation board. And do the recognition test with select set 1 and set 3 parameter that has good recognition rate on commander and no digit after the several tests using by 5 proposal recognition parameter sets. The recognition engine of recognition rate shows 95%, speech commander recognizer shows 96% and digits recognizer shows 94%.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.4
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• pp.469-479
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• 2015

This study have been conducted to analyze the feasibility of establishing Contamination Warning System(CWS) that is capable of monitoring early natural or intentional water quality accidents, and providing active and quick responses for domestic C_water supply system. In order to evaluate the water quality data set, pH, turbidity and free residual chlorine concentration data were collected and each statistical value(mean, variation, range) was calculated, then the seasonal variability of those were analyzed using the independent t-test. From the results of analyzing the distribution of outliers in the measurement data using a high-pass filter, it could be confirmed that a lot of lower outliers appeared due to data missing. In addition, linear filter model based on autoregressive model(AR(1) and AR(2)) was applied for the state estimation of each water quality data set. From the results of analyzing the variability of the autocorrelation coefficient structure according to the change of window size(6hours~48hours), at least the window size longer than 12hours should be necessary for estimating the state of water quality data satisfactorily.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.10
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• pp.73-81
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• 2015

The paper proposes a prototype selection method and evaluates the generalization performance of standard algorithms and prototype based classification learning. The proposed prototype classifier defines multidimensional spheres with variable radii within class areas and generates a small set of training data. The nearest-neighbor classifier uses the new training set for predicting the class of test data. By decomposing bias and variance of the mean expected error value, we compare the generalization errors of k-nearest neighbor, Bayesian classifier, prototype selection using fixed radius and the proposed prototype selection method. In experiments, the bias-variance changing trends of the proposed prototype classifier are similar to those of nearest neighbor classifiers with all training data and the prototype selection rates are under 27.0% on average.

• Bulletin of the Korean Chemical Society
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• v.31 no.8
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• pp.2163-2169
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• 2010

G-protein coupled receptors (GPCRs) are involved in a wide variety of physiological processes and are known to be targets for nearly 50% of drugs. The various functions of GPCRs are affected by their cognate ligands which are mainly classified as agonists and antagonists. The purpose of this study is to develop a Bayesian classification model, that can predict a compound as either human GPCR agonist or antagonist. Total 6627 compounds experimentally determined as either GPCR agonists or antagonists covering all the classes of GPCRs were gathered to comprise the dataset. This model distinguishes GPCR agonists from GPCR antagonists by using chemical fingerprint, FCFP_6. The model revealed distinctive structural characteristics between agonistic and antagonistic compounds: in general, 1) GPCR agonists were flexible and had aliphatic amines, and 2) GPCR antagonists had planar groups and aromatic amines. This model showed very good discriminative ability in general, with pretty good discriminant statistics for the training set (accuracy: 90.1%) and a good predictive ability for the test set (accuracy: 89.2%). Also, receiver operating characteristic (ROC) plot showed the area under the curve (AUC) to be 0.957, and Matthew's Correlation Coefficient (MCC) value was 0.803. The quality of our model suggests that it could aid to classify the compounds as either GPCR agonists or antagonists, especially in the early stages of the drug discovery process.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1363-1369
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• 2015

The frequency of a power system should be maintained within the allowed limits for stable operation. When a disturbance such as generator tripping occurs in a power system, the frequency is recovered to the nominal value through the inertial, primary, and secondary responses of the operating synchronous generators (SGs). However, for a power system with high wind penetration, the system inertia will decrease significantly because wind generators (WGs) are operating decoupled from the power system. This paper proposes a dynamic droop-based inertial control for a WG. The proposed inertial control determines the dynamic droop depending on the rate of change of frequency (ROCOF). At the initial period of a disturbance, where the ROCOF is large, the droop is set to be small to release a large amount of the kinetic energy (KE) and thus the frequency nadir can be increased significantly. However, as times goes on, the ROCOF will decrease and thus the droop is set to be large to prevent over-deceleration of the rotor speed of a WG. The performance of the proposed inertial control was investigated in a model system, which includes a 200 MW wind power plant (WPP) and five SGs using an EMTP-RV simulator. The test results indicate that the proposed scheme improves the frequency nadir significantly by releasing a large amount of the KE during the initial period of a disturbance.