• Journal of the Korean Institute of Intelligent Systems
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• v.13 no.3
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• pp.322-327
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• 2003

The water level of a steam generator of pressurized light water nuclear Power generator is known as a subject whose control is difficult because of a shrinking and swelling effect that is been mutually contradictory in a variation of feed water. In this paper, a neural network model selects first coordinative controller by a inappropriate gain of two PI controllers and the selected controller＇s gain is tuned by a fuzzy self-tuner. Model inputs consist of the water level, the feed water, and the stream flow. One controller of both coupling controllers whose gain is handled firstly is decided based upon above data. The proposed method can analyze patterns of signals using the characteristic of neural networks and select one controller that needs to be tuned through the observed result in this paper. If one controller between both the water level controller and the feed water controller is selected by the neural network model then a gain of the PI controller is suitably tuned by the fuzzy self-tuner. Rules of the fuzzy self-tuner drew from the pattern of input and output data. In the summary, the goal of this Paper is to select the suitable controller and tune the control gain of the selected controller suitably through such two processes.

• Child Health Nursing Research
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• v.6 no.3
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• pp.372-386
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• 2000

The purpose of this study was to provide basic data on preschool children for accident prevention and improve their health through sound, safe living environment with safety education established through more systematic method. Data were collected from 300 preschoolers(150 preschooler are assigned to experimental group and 150 preschoolers are assigned to control group) from 4 to 6 years old using APP paper test which consists of questions and drawings. To experimental group, safety education were done 4 times within the time of 30 minutes per 1 time using education books, video, OHP, slide. The findings of this study are as follows: 1. There were significant difference in behavioral character between experimental group and control group(χ2=11.690, p= 0.003). So, safety education have effect on the behavioral character of preschooler. 2. In the accident proneness on preschooler between experimental group and control group according to general characteristics, it proved significant difference in the case of accident prevention education were done, movement stability(χ2=8.844, p=0.012) and behavioral character(χ2=6.699, p=0.035), in the case of housing pattern is mixed-type, behavioral character(χ2=10.37, p=0.006), in the case of subjects' age is 4 years old, watchfulness(χ2=9.525, p=0.009), in the case of subjects' age is 5 years old, behavioral character(χ2=7.324, p=0.026), in the case of children's order is second, behavioral character(χ2=14.31, p=0.001), in the case of children's sex is boy, living safety(χ2=7.981, p=0.018), movement speed (χ2=6.661, p=0.036), bihavioral character(χ2=8.837, p=0.012), in the case of children's sex is girl, reasoning power(χ2 =9.78, p=0.008), in the case of childrens have no past accidental experience, behavioral character(χ2=9.862, p=0.007), in the case of nuclear family, movement speed(χ2=6.341, p=0.042) and behavioral character(χ2=9.326, p=0.009), in the case of mothers' age is under thirty behavioral character(χ2=16.40, p=0.000), in the case of mothers' school career is under high school graduate, behavioral character(χ2 =8.375, p=0.015), in the case of mothers' school career is beyond college graduate, reasoning power(χ2=9.803, p=0.007) and behavioral character(χ2=6.205, p=0.045), in the case of mothers' job is part time, movement speed(χ2=10.99, p=0.004), in the case of mothers have no job, movement stability(χ2=8.490, p=0.014) and behavioral character(χ2=10.11, p=0.006). The difference of accident proneness between experimental group and control group according to general characteristics, it also showed that there were significant difference in behavioral character compared to other area.. From this findings, we can guess that safety education change and guide preschoolers' behavioral character to desirable direction.

• Journal of the Korean Home Economics Association
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• v.39 no.11
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• pp.129-144
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• 2001

In spite of rapid sociocultural changes and an increase in the number of nuclear families in recent years, quite many families in Korea still have taken the extended family form where daughter-in-law provides care for the elderly parents. Even though the nature of the inter-generational relationship in Korea is reciprocal in many regards, most of the studies looked at the burden or costs of coresidence with the elderly parents while relatively little attention has been given to the positive side of the coresidence. This study is an attempt to fill this gap in the area. The purpose of this study is to examine not only the costs but also benefits of the coresidence with the elderly parents. We also explore whether there is a rural-urban differences in costs and benefits of coresidence and related factors. For the purpose, data were gathered from 876 daughters-in-law of three generational family both in rural and urban area, using structured questionnaire. The statistical methods used for data analysis were descriptive statistics, cross tables, and regression analysis with SPSS/PC+ program. The major findings of this study were as follows: Marital and economic status of the elderly parents, age, job status and filial responsibility attitude of caregiver, sibling support, and coresidence duration were the significant variables predicting the level of perceived benefits. Marital status of elderly parents, income, job status, educational level, and filial responsibility altitude of caregiver, residence region affected the level of perceived costs. Rural-urban differences are found in many aspects of coresidence experiences and related factors. Rural caregivers receive higher level of the sibling support, have more traditional final responsibility altitude and perceived less costs and more benefit than urban caregivers. There also are differences in the factors influencing the level of perceived costs and benefits between rural and urban area. Level of sibling support and final responsibility attitude have significant impact on both the perceived costs and benefits. But there are differences in terms of that perceived costs and benefits of urban caregivers are affected by job status of caregivers while those of rural caregivers are affected by educational level of caregivers and marital status of elderly. The results confirm that Korean caregivers experience both positive and negative aspects of coresidence and shows that the nature of the inter-generational relationships differ between rural and urban Korea.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.1
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• pp.38-45
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• 2017

Objectives: Radon may be second only to smoking as a cause of lung cancer. Radon is a colorless, tasteless radioactive gas that is formed via the radioactive decay of radium. Therefore, radon levels can build up based on the amount of radium contained in construction materials such as phospho-gypsum board or when ventilation rates are low. This study provides our findings from evaluation of radon gas at facilities and offices in an industrial complex. Methods: We evaluated the office rooms and processes of 12 manufacturing factories from May 14, 2014 to September 23, 2014. Short-term data were measured by using real-time monitoring detectors(Model 1030, Sun Nuclear Co., USA) indoors in the office buildings. The radon measurements were recorded at 30-minute intervals over approximately 48 hours. The limit of detection of this instrument is $3.7Bq/m^3$. Also, long-term data were measured by using ${\alpha}-track$ radon detectors(${\alpha}-track$, Rn-tech Co., Korea) in the office and factory buildings. Our detectors were exposed for over 90 days, resulting in a minimum detectable concentration of $7.4Bq/m^3$. Detectors were placed 150-220 cm above the floor. Results: Radon concentrations averaged $20.6{\pm}17.0Bq/m^3$($3.7-115.8Bq/m^3$) in the overall area. The monthly mean concentration of radon by building materials were in the order of gypsum>concrete>cement. Radon concentrations were measured using ${\alpha}-track$ in parallel with direct-reading radon detectors and the two metric methods for radon monitoring were compared. A t-test for the two sampling methods showed that there is no difference between the average radon concentrations(p<0.05). Most of the office buildings did not have central air-conditioning, but several rooms had window- or ceiling-mounted units. Employees could also open windows. The first, second and third floors were used mainly for office work. Conclusions: Radon levels measured during this assessment in the office rooms of buildings and processes in factories were well below the ICRP reference level of $1,000Bq/m^3$ for workplaces and also below the lower USEPA residential guideline of $148Bq/m^3$. The range of indoor annual effective dose due to radon exposure for workers working in the office and factory buildings was 0.01 to 1.45 mSv/yr. Construction materials such as phospho-gypsum board, concrete and cement were the main emission sources for workers' exposure.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.119-130
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• 2016

This study was conducted to investigate the effects of individual patient behavior regarding health and medical care level on doctor's diagnoses of hypertension. A X2-test was used to compare therapeutic compliance in individual characteristics and two-stage multilevel logistic regression to identify community variance of the related index of high blood pressure therapeutic compliance using data from 229,229 adults over the age of 19 in a community health survey conducted in 2010. The experience rate of doctors' diagnoses of hypertension was higher for people of older age, higher level of education, higher BMI, and among heavy drinkers (no recipients of basic living). Furthermore, there was a higher rate for those visiting health and medical institutions, having more frequent checks of blood pressure in a month, having a higher stress level, and having depression. Among paid workers, the ratio was lower for employers and owner/operators with more daily exercise (such as walking), infrequent smokers, and private health insurance holders. Doctor's diagnoses of hypertension was affected by individual health behavior and health and medical care level. Further studies employing multilevel analyses considering regional level data should be conducted in the future.

• Korean Journal of Soil Science and Fertilizer
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• v.28 no.2
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• pp.160-164
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• 1995

This study was conducted to obtain quantitative data on the behavior of surface-applied urea to a paddy field which would help to protect against environmental pollution as well as to increase the efficiency of nitrogen fertilizer. The percolating water samples were collected with porous ceramic cups installed at 25, 50 and 75cm depths in a paddy field during the rice growing season(June 1992-September 1992) and analyzed for urea-N. NHAN and $NO_3-N$. In the paddy field to which urea fertilizer was applied at the rates of 12 and 24kg N/10a, the surface-applied urea was detected even at 75cm depth as the form of urea-N upto 12days after application. The maximum concentrations of urea-N in the percolating water sampled at 25, 50 and 75cm depths were the same irrespective of soil depth and the values were 0.06 and $0.12{\mu}g/m{\ell}$ for the application rates of 12 and 24kg N/10a respectively. The concentrations of $NH_4-N$ gradually decreased with time during the vegetative growth period : thereafter. the concentrations remained nearly constant. The maximum concentrations of $NH_4-N$ at 25cm depth were 1.2 and $5.6{\mu}g/m{\ell}$ for 12 and 24kg N/10a rate respectively. The $NO_3-N$ concentrations of percolating water ranged 0.1~0.5 and $0.2{\sim}0.5{\mu}g/m{\ell}$ for urea application rates of 12 and 24kg N/10a respectively. The nitrate concentration data suggest that nitrification process occurred continuously in paddy field during the rice growing season.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.16 no.4
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• pp.473-478
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• 2018

Radioactive aerosol generated in cutting and melting work during the NPP decommissioning process can cause internal exposure to body through workers' breath. Thus, it is necessary to assess worker internal exposure due to the radioactive aerosol during decommissioning. The actually measured value of the working environment is needed for accurate assessment of internal exposure, but if it is difficult to actually measure that value, the internal exposure dose can be estimated through recommended values such as the fraction of amount of intake and the size of particles suggested by the International Committee on Radiological Protection (ICRP). As for the selection of particle size, this study applied a value of $5{\mu}m$, which is the size of particles considering the worker recommended by the ICRP. As for the amount of generation, the amount of intake was estimated using data on the mass of aerosol generated in a melting facility at a site in Kozloduy, Bulgaria. In addition, using these data, this study calculated the level of radioactivity in the worker's body and stool and conducted an assessment of internal exposure using the BiDAS computer code. The internal exposure dose of Type M was 0.0341 mSv, that of Type S was 0.0909 mSv. The two types of absorption showed levels that were 0.17% and 0.45% of the domestic annual dose limit, respectively.

• Korean Journal of Otorhinolaryngology-Head and Neck Surgery
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• v.61 no.12
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• pp.697-701
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• 2018

Background and Objectives The aim of this study was to evaluate surgical completeness in endoscopic total thyroidectomy with central neck dissection via unilateral axillo-breast approach (UABA) compared with bilateral axillo-breast (BABA) and open approach (OA) by means of the radioactive iodine uptake (RAIU) ratio and thyroglobulin (Tg) of remnant thyroid. Subjects and Method From July 2010 to March 2013, 82 patients who had underwent total thyroidectomy with central neck dissection and postoperative radioactive iodine (RAI) ablation for papillary thyroid carcinoma were enrolled. Of these patients, 27 patients underwent UABA, 24 patients BABA, and 31 patients OA. Clinicopathologic data, surgical outcome, stimulated Tg and RAIU ratio on the first postoperative RAI ablation scan were compared among 3 groups. Results Patients in the endoscopic surgery groups (UABA, BABA) were younger than those in the OA groups. Invasiveness such as operation time, postoperative pain, and drain amount in UABA was less than that in BABA and severer than that in OA. Other variables regarding clinicopathologic and surgical data were not significantly different. Stimulated Tg and RAIU ratio did not show significant differences among 3 groups (p=0.659 and p=0.664). Conclusion The completeness of UABA was comparable with that of BABA and OA. The UABA may be a safe option for patients who need endoscopic thyroidectomy for papillary thyroid carcinoma.

• Explosives and Blasting
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• v.39 no.4
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• pp.22-33
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• 2021

Recently, the frequent occurrence of ground subsidence in urban areas has caused increasing anxiety in residents and incurred significant social costs. Among the causes of ground subsidence, the rupture of old water and sewer pipes not only halts the operation of the buried pipes, but also leads to ground and water pollution problems. However, because most pipes are buried after construction and cannot be seen with the naked eye, the importance of maintenance has underestimated compared to other structures. In recent years, integrated physical exploration has been applied to the maintenance of underground pipes and structures. Currently, to investigate the internal conditions and vulnerable portions of the ground, consolidated physical surveys are executed. Consolidated physical surveys are analysis techniques that obtain various material data and add existing data using multiple physical surveys. Generally, in geotechnical engineering, consolidated physical surveys including electrical and surface wave surveys are adopted. However, it is difficult to investigate time-based changes in under ground using these surveys. In contrast, surveys using cosmic-ray muons have been used to scan the inner parts of nuclear reactors with penetration technology. Surveys using muons enable real-time observation without the influence of vibration or electricity. Such surveys have great potential for available technology because of their ability to investigate density distributions without requiring as much labor. In this paper, survey technologies using cosmic ray muons are introduced, and the possibilities of applying such technologies as new physical survey technologies for underground structures are suggested.

• Journal of Korea Water Resources Association
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• v.55 no.7
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• pp.515-529
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• 2022

Identifying the available water resources amount is an essential process in establishing a sustainable water resources management plan. Dam facility is a major infrastructure storing and supplying water during the dry season, and the water supply yield of the dam varies depending on dam inflow conditions or operation rule. In South Korea, water supply yield of dam is calculated by reservoir simulation based on observed historical dam inflow data. However, the water supply capacity of a dam can be underestimated or overestimated depending on the existence of historical drought events during the simulation period. In this study, probabilistic inflow data was generated and used to estimate the appropriate range of the water supply yield of hydropower dams. That is, a method for estimating the probabilistic dam inflow that fluctuates according to climatic and socio-economic conditions and the range of water supply yield for hydropower dams was presented, and applied to hydropower dams located in the Han river in South Korea. It is expected that the understanding water supply yield of the hydropower dams will become more important to respond to climate change in the future, and this study will contribute to national water resources management planning by providing potential range of water supply yield of hydropower dams.