• Proceedings of the Korea Water Resources Association Conference
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• 2002.05a
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• pp.43-50
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• 2002

Accurate quantitative forecasting of rainfall for basins with a short response time is essential to predict streamflow and flash floods. Previously, neural networks were used to develop a Quantitative Precipitation Forecasting (QPF) model that highly improved forecasting skill at specific locations in Pennsylvania, using both Numerical Weather Prediction (NWP) output and rainfall and radiosonde data. The objective of this study was to improve an existing artificial neural network model and incorporate the evolving structure and frequency of intense weather systems in the mid-Atlantic region of the United States for improved flood forecasting. Besides using radiosonde and rainfall data, the model also used the satellite-derived characteristics of storm systems such as tropical cyclones, mesoscale convective complex systems and convective cloud clusters as input. The convective classification and tracking system (CCATS) was used to identify and quantify storm properties such as life time, area, eccentricity, and track. As in standard expert prediction systems, the fundamental structure of the neural network model was learned from the hydroclimatology of the relationships between weather system, rainfall production and streamflow response in the study area. The new Quantitative Flood Forecasting (QFF) model was applied to predict streamflow peaks with lead-times of 18 and 24 hours over a five year period in 4 watersheds on the leeward side of the Appalachian mountains in the mid-Atlantic region. Threat scores consistently above .6 and close to 0.8 ∼ 0.9 were obtained fur 18 hour lead-time forecasts, and skill scores of at least 4％ and up to 6％ were attained for the 24 hour lead-time forecasts. This work demonstrates that multisensor data cast into an expert information system such as neural networks, if built upon scientific understanding of regional hydrometeorology, can lead to significant gains in the forecast skill of extreme rainfall and associated floods. In particular, this study validates our hypothesis that accurate and extended flood forecast lead-times can be attained by taking into consideration the synoptic evolution of atmospheric conditions extracted from the analysis of large-area remotely sensed imagery While physically-based numerical weather prediction and river routing models cannot accurately depict complex natural non-linear processes, and thus have difficulty in simulating extreme events such as heavy rainfall and floods, data-driven approaches should be viewed as a strong alternative in operational hydrology. This is especially more pertinent at a time when the diversity of sensors in satellites and ground-based operational weather monitoring systems provide large volumes of data on a real-time basis.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.2
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• pp.17-29
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• 2020

The objective of this study was to find an optimum methane yield condition in anaerobic digestion of sewage sludge with microwave pretreatment. The pretreatment process was carried out using a lab scale industrial microwave unit (2,450 MHz frequency). The digestion efficiency of pretreated sludge was evaluated by biochemical methane potential (BMP) test. Box-Behnken design and Response Surface Analysis (RSA) were applied to determine the optimal combination of sludge mixing ratio (0 to 100%), power (400 to 1600 W), holding time (0 to 10 min) and pretreatment temperature (60 to 100℃). BMP test results showed that Volatile Solid (VS) removal efficiency was up to 48% at a condition of 0% for mixing ratio, 1600 W for power, 5 min for holding time, and 80℃ for pretreatment temperature. Methane production was up to 832.3 mL/g VS_removed at a condition of 50% for mixing ratio, 1000 W for power, 5 min for holding time, and 80℃ for pretreatment temperature. The results of the variance analysis (ANOVA) showed that the p-value of the power and pretreatment temperature among the independent variables were significant (p<0.05), and in particular, the pretreatment temperature significantly affected on the solubilization and methane production. The optimum condition for the maximum methane yield (847 mL/g VS_removed) was consist of 38.4% of mixing ratio, 909.1 W of power, 4.1 min of holding time, and 80℃ of temperature within the design boundaries.

• The Journal of Engineering Geology
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• v.30 no.3
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• pp.347-378
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• 2020

Based on monthly average groundwater recharge over a nearly 10 year period, results of fully integrated hydrologic modeling of SWAT-MODFLOW, land cover, land use, soil type and hydrologic response unit (HRU) was used to assess the dominant influencing factors of groundwater recharge spatial patterns in Jangseong district. As dominant factors, land cover was FRSE (forest-evergreen) and soil type was Samgag. Landsat-8 OLI imaging spectrometer data were acquired in the period 2003 to 2004 and seasonal bare soil lines (BSL) were estimated through NIR-RED plot. Extent of slope of BSL was from 1.092 to 1.343 and the intercept was from -0.004 to -0.015. To know correlation between spatial groundwater recharge and soil-vegetation indices (PVI, NDVI, NDTI, NDRI), this study employed frequency and regression analysis. On May, RED band increased up 3 to 4 times compared to other seasons and only one turning point appeared as recharge-index with upward parabola bell shape as results of existing research. Considering precipitation, if the various studies for relationship between groundwater recharge and soil-vegetation index just like NDVI are performed, it is possible to estimate groundwater recharge through analyzing remote sensing data.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.11
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• pp.1423-1433
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• 2018

Recently, a permanent magnet synchronous motor of middle and small-capacity has high torque, high precision control and acceleration / deceleration characteristics. But existing control has several problems that include unpredictable disturbances and parameter changes in the high accuracy and rigidity control industry or nonlinear dynamic characteristics not considered in the driving part. In addition, in the drive method for the control of low-vibration and high-precision, the process of connecting the permanent magnet synchronous motor and the load may cause the response characteristic of the system to become very unstable, to cause vibration, and to overload the system. In order to solve these problems, various studies such as adaptive control, optimal control, robust control and artificial neural network have been actively conducted. In this paper, an incremental encoder of the permanent magnet synchronous motor is used to detect the position of the rotor. And the position of the detected rotor is used for low vibration and high precision position control. As the controller, we propose augmented state feedback control with a speed observer and first order deadbeat disturbance observer. The augmented state feedback controller performs control that the position of the rotor reaches the reference position quickly and precisely. The addition of the speed observer to this augmented state feedback controller compensates for the drop in speed response characteristics by using the previously calculated speed value for the control. The first order deadbeat disturbance observer performs control to reduce the vibration of the motor by compensating for the vibrating component or disturbance that the mechanism has. Since the deadbeat disturbance observer has a characteristic of being vulnerable to noise, it is supplemented by moving average filter method to reduce the influence of the noise. Thus, the new controller with the first order deadbeat disturbance observer can perform more robustness and precise the position control for the influence of large inertial load and natural frequency. The simulation stability and efficiency has been obtained through C language and Matlab Simulink. In addition, the experiment of actual 2.5[kW] permanent magnet synchronous motor was verified.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.6
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• pp.587-593
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• 2020

The securing safety of ferry ships on the domestic coast is evaluated by comparing the external force applied and the securing device based on the cargo weight and hull acceleration that can exist at the loaded position. The hull acceleration based on the domestic standard, which is the basis for securing safety evaluation, is applied without reflecting the characteristics of the ship and the sailing conditions. In this study, a total of 12 acceleration measurements were performed at four points of the hull of a ship with a DWT 6,800 ton class 15.5 knots passing through Busan-Jeju to analyze the hull acceleration of the domestic coastal ferry ship. Data were collected for the buoy. For a theoretical comparative analysis of the limited measurement results, the response amplitude operator (RAO) was analyzed through frequency-response analysis by numerical simulation, and acceleration analysis for the four points was performed using the RAO results. Based on the acceleration comparison, differences in the degree of each position were observed, but in the case of the Y-axis acceleration, the analysis was 1.81 m/s², and the measurement was 1.47 m/s². The analyzed simulation result was as high as 0.34 m/s². Moreover, analysis was performed at 22 % level, and measurement at 18 % level.

• Journal of Distribution Science
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• v.11 no.2
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• pp.71-81
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• 2013

Purpose - The TOEIC test has been leading the change in the quality and the globalization of companies for about last 30 years. The TOEIC test is taken by about two million people each year and is used as a criterion to select new employees in companies or government offices, for performance ratings, and for overseas posting selections. Universities also use TOEIC test in various ways. Since the TOEIC test is used for the selection of new students for admission, transferring extra credits, scholarships, graduation certification, and admission of international students studying abroad, many universities all over the country provide students with TOEIC study lectures through their own language institutes. Despite the fact, there has been no research on the service quality or even the current situation of these institutes. Thus, this study aims to evaluate the factors that impact TOEIC lecture service quality and analyzes the effect of the expectation related to the education service quality and the result of education on intentional behavior. Research design, data, methodology - Data was collected by administering a survey to current TOEIC students from different university language institutes. The survey questionnaire comprised of a five-point Likert scale. The demographic analysis was conducted using the frequency analysis method and the factor analysis was conducted to verify the validity of questionnaire over any variable. The reliability analysis was conducted to verify the reliability of the results. Besides, multiple regression analysis, regression analysis, and mediated effect verification were also conducted. For education service quality, four different independent variables such as reliability, response, conviction, and sympathy were considered using the SERVQUAL survey model. Based on the research models, the study hypotheses below were formulated in order to recognize an effect relationship between the variables. The four hypotheses are, "the hypothesis on education service quality and TOEIC study result expectation," "the hypothesis on education service quality and behavioral intention," "the hypothesis on study result expectation and behavioral intention," and "the hypothesis on study result expectation and mediated effect." Results - The results are as follows. First, the factors like response, conviction, and sympathy have a positive influence on TOEIC study result expectations. Second, the TOEIC study result expectation has a positive influence on the factors of behavioral intention such as re-sign up, positive word-of-mouth, "loyalty towards school." Third, it was verified that the mediated effect on behavioral intention was influenced by education service quality at university foreign language institute, while the study result expectation has only a partial mediated effect. Conclusions - The implications of this study are summarized as follows: First, it suggests a new research model for the effect of the expectation related to the education service quality and the result of education in the university language institutes on the behavioral intention. Second, it has established a relationship between the education service quality and study result expectation by verifying the mediated effect on them.

• The Korean Journal of Pharmacology
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• v.19 no.2
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• pp.25-34
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• 1983

In this isolated study, it was aimed to elucidate the pharmacological properties of non-cholinergic, non-adrenergic inhibitory responses in the longitudinal strips of rabbit portal vein. 1) The portal vein responded inhibitory to electrical field stimulation in a frequency - and calcium-dependent manner after pretreatment with atropine, guanethidine and ergotamine, simultaneously. 2) When exogenous ATP, ADP, adenosine and cyclic AMP were added, respectively, they only showed the relaxations in the higher concentration without mimicing or affecting the inhibitory response induced by the electrical stimulation. The antagonist of purine substances, neither quinine nor isobutyl-methyl xanthine did influence on the relaxation. 3) The inhibitory response was significantly increased in the presence of $1{\mu}g/ml 4-amino-pyrineine (4-AP) which is $K^+-conduction$ blockade, but higher concentration of 4-AP directly decreased the vascular tone. 4) Though repeated application of ATP revealed the inhibitory effect on the relaxation, however, that of adenosine resulted rather increase of the amplitude. 5) After pretreatment with $^3H-adenosine$, $^3H-efflux$ induced by ATP or adenosine was markedly enhanced, but the electrical stimulation caused less $^3H-efflux$. 6) ^3H-efflux by electrical stimulation was not affected by the administration 4-AP, tetrodotoxin and adenosine.

• Journal of Korean Public Health Nursing
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• v.12 no.2
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• pp.236-251
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• 1998

This study aimed at comprehending the meaning of sexual life for aged people, their strength of sexual desire and causes of change in their sexual life. It was another purpose to understand the extent of aged people's acknowledging the necessity of sexual consultation. This study adopted descriptive method using open-ended questionaires. The data for study was collected from 26 people over 65 years who reside in communities. It was gathered from April to June of 1998 through interview. The interviewee includes 16 males, 9 females and their average age was 73.3. 19 people among them have spouses. The conclusion of this study can be summarized as follows. 1) Attitude to sexual life: The meaning of sexual life for aged people is categorized as 'sense of duty', 'feeling of intimacy', 'basic desire', 'decrease of meaning' and 'meaningless'. 2) Sexual desire: Sexual desire of aged people is categorized as 'extinction', 'decrease', 'continuation' and 'restraint'. Restraint of sexual desire is due to social convention or the difficulty in fulfilling desire. 3) Causes of troubles in sexual life Causes which lead to troubles in sexual life of aged people can be categorized as 'physical', 'psychological' and 'social'. 'Physical' elements include 'incompetence of erection', 'decrease in duration of erection', 'increase in time needed to re-erection', 'declining of physical strength', 'decrease in vagina secretion' and 'worsening of health'. Among 'psychological' elements 'decrease of self-confidence', 'diminished concern of female aged people' are. 'Social elements' are 'absence of sexual parter', 'circumstances of living' and 'recognition of neighbor'. 4) Response to change of sexual life The reaction of aged people to change of sexual activities is classified as 'positive' and 'negative'. 5) Attitude to the consultation of sexual life of aged people The attitude to the consultation of sexual life in old age is classified as 'negative', 'doubtful' and 'positive'. This study explored the meaning which aged people in community attach to sexual life, the extent of their sexual desire, the causes of troubles in their sexual life, their emotional response to changes in sexual life, their recognition of necessity in sexual consultation. Considering the frequency of the statement, most of aged people who were interviewed thought much of sexual life and put emphasis on it. Those who said that sexual life has decreased meaning or is not important to them are few, Though aged people still maintain sexual desire, most of them have some trouble in sexual life. These trouble changes the sexual life, and results in negative feeling such as depression, renunciation and difficulty in relations. So they acknowledged that sexual consultation is necessary to them.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.8
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• pp.1193-1198
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• 2003

An increase in frequency of administration of exogenous growth hormone (GH) or GH-releasing hormone was reported to be a model to increase blood circulating insulin-like growth factor-1 (IGF-1) and to improve growth performance in animals. We have investigated the effect of twice daily administration of GH-releasing peptide-2 (GHRP-2) on growth performance, GH responsiveness and plasma insulin-like growth factor IGF-1 in swine. We administered to eight swine, 3 control and 5 treatment, a twice daily s.c. injections of GHRP-2 ($30{\mu}g/kg\;BW$) for a period of 10 days. Every day blood samples immediately taken before injections of GHRP-2 or saline, at 08:00 h and 16:00 h, were measured for IGF-1 concentrations. Blood samples for GH assay were collected every 20 min on days 1, 6 and 10, from 1 hour before and 3 h after GHRP-2 or saline injections at 08:00 h. GH peak concentrations and GH area under curve (GH AUC) on day 1, 6 and 10 in treatment group of swine were higher than those in control swine (p<0.05). Twice daily administration of GHRP-2 caused a significantly attenuation (p<0.05) of GH peak concentrations ($80.25{\pm}13.87$, $39.73{\pm}5.72$ and $27.57{\pm}6.06ng/ml$ for day 1, 6 and 10, respectively) and GH AUCs ($3,536.15{\pm}738.35$, $1,310.31{\pm}203.55$ and $934.37{\pm}208.99ng/ml$ for day 1, 6 and 10, respectively). However, there was no significant difference in GH peak concentration and GH AUC between day 6 and 10. Plasma IGF-1 concentration levels were higher in treatment than control group of swine (p<0.05) after 3 days of the treatment, and the levels reached a plateau from day 3 to 10 of experiment. Growth performance did not alter by GHRP-2 administration, even though a numerical increase of body weight gain and feed efficiency was observed. These results indicate that twice daily administration of GHRP-2 for 10 days in swine did not significantly influence on growth performance, caused an overall attenuation of GH response, and that elevation of plasma GH concentrations caused by GHRP-2 administration increased plasma IGF-1 concentrations, even though an attenuation of GH response was observed.

• Journal of the Korean School Mathematics Society
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• v.5 no.2
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• pp.1-15
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• 2002

The purpose of this study came to start to be helpful in that the teachers in field produced evaluation subject about the mathematics and applied by analyzing the performance capacity for the students about the subject developed through the application of subject about the teaching-learning model that can utilize the learners' learning experience and the development of items that can evaluate it by utilizing various and concrete operational materials as an object of the first year at the middle schools. The concrete purpose of realizing it is as follows. 1. This study is to develop the teaching-learning model centered on activities adequate to utilize various and concrete operational materials. 2. This study is to develop evaluation data for utilizing the concrete operational materials by making construction through the application of developed teaching-learning model as possible. 3. This study is to present standards initiative for reliable and fair marking about the evaluation data and to analyze the students' practice capacity by using it effectively. For accomplishing the purpose of this research, this study is the work-oriented teaching and learning model using learning data that can be easily found around the surroundings and 8 evaluation programs in order that the experience-oriented learning based on circumstances learning among the learning models of constructivism. Also, it is to examine the result after applying that on a basis of 25 students, consisted of only on class in a year, in the first year at the small size of agricultural middle schools. The result of this study from this research is as follows. First, as a result of frequency survey, of response about the developed evaluation data it showed positive response more than 80% of all the items. The atmosphere of self-directed learning was produced because the developed evaluation data could induce activity-based learning naturally by stimulating the students' curiosity and promoting interest. Second, this study executed t-test for the result of questionnaire about the mathematics propensity, and there were significant differences in 19 items among 25 items. It presented that the application of data about the teaching-learning and evaluation directly using concrete operational materials to the constructional learning by level might have desirable affect on the students' mathematical propensity. It came to be a motive that could increase value recognition and interest on the subject of mathematics by investigating a mathematical principle rule and confirming it through activity learning using the concrete operational materials.