• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.63-69
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• 2002

Construction of Private networks is becoming easier due to the openness of telecommunication market, rapidly developing telecommunication technology. The size of existing private networks is becoming huge which resulted in surplus of capacity of the networks. These trends will generate a problem of efficient use of "national telecommunication resources" and which ill be a factor for the structure of domestic telecommunication market which will have a big impact on the existing telecommunication carriers. Therefore, national policy of private network issues should be considered along with the national efforts for the information infrastructure, control of telecommunication market, fairness of competition, strength power of national competition. In this paper it will be suggested that the efficient policy on the issue of domestic private network, by analyzing present situation, status quo, laws, regulation and procedure for domestic private networks and comparing it with those of U.S.A, Japan, EU.apan, EU.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.341-346
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• 2019

This study analyzed the relationship between the personality factors in pre-service early childhood teachers and teacher efficacy. To carry out the research, this experiment subjected 228 pre-service early childhood teachers in G city. The collected data were descriptive methods, Pearson correlation analysis and multiple regression using the SPSS 22.0 program. The results of this study were as follows. First, there were significant positive relationships among the personality factors and teacher efficacy. Second, the personality factors was an important factor for predicting the teacher efficacy of pre-service early childhood teachers. Also, the explanation power of personality factors for teacher efficacy of pre-service early childhood teachers was 25%, extroversion is one of the most personality factors of infant pre-serve early childhood teacher. Therefore, according to this research, a preserves early childhood teacher training program for improvement of extraversion in personality factors is strongly desired.

• Nuclear Engineering and Technology
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• v.54 no.6
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• pp.2077-2083
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• 2022

In the unlikely event of core disruptive accident in sodium cooled fast reactors, the reactor containment building would be bottled up with sodium and fission product aerosols. The behavior of these aerosols is crucial to estimate the in-containment source term as a part of nuclear reactor safety analysis. In this work, the evolution of sodium aerosol characteristics (mass concentration and size) is simulated using HAARM-S code. The code is based on the method of moments to solve the integro-differential equation. The code is updated to FORTRAN-77 and run in Microsoft FORTRAN PowerStation 4.0 (on Desktop). The sodium aerosol characteristics simulated by HAARM-S code are compared with the measured values at Aerosol Test Facility. The maximum deviation between measured and simulated mass concentrations is 30% at initial period (up to 60 min) and around 50% in the later period. In addition, the influence of humidity on aerosol size growth for two different aerosol mass concentrations is studied. The measured and simulated growth factors of aerosol size (ratio of saturated size to initial size) are found to be matched at reasonable extent. Since sodium is highly reactive with atmospheric constituents, the aerosol growth factor depends on the hygroscopic growth, chemical transformation and density variations besides coagulation. Further, there is a scope for the improvement of the code to estimate the aerosol dynamics in confined environment.

• Journal of dental hygiene science
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• v.22 no.2
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• pp.67-74
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• 2022

Background: Depression and cognitive function have a positive effect on the improvement of quality of life and extension of lifespan in the elderly. In addition, it appears as a major factor influencing oral health status. Therefore, this study looked at the relationship between the Geriatric Oral Health Assessment Index (GOHAI), depression, and cognitive function in the elderly using the Korea Longitudinal Study of Aging. Methods: In this study, 4,535 elderly people aged 65 years and over were targeted using the 7th data of the 2018 Korea Longitudinal Study of Aging. A t-test and ANOVA analysis were performed to compare GOHAI, depression, and cognitive function by group. In addition, hierarchical multiple linear regression was performed to understand the effect of the elderly's perceived depression scale and cognitive ability on GOHAI. Results: As a result of adding the depression scale and cognitive function variables to Model 2, the explanatory power was 22%. Educational level, marital status, private health insurance subscription, average monthly allowance, subjective health status, use of dentures, smoking status, economic activity, depression scale, and cognitive function were found to have significant influence (p<0.05). In addition, when controlled and viewed with all factors, depression and cognitive function were found to have an effect on oral health-related quality of life. Conclusion: The findings indicate that depression and cognitive function are associated with oral health-related quality of life in the Korean elderly. As the age increases, the quality of life declines due to depression and cognitive function problems, in addition to oral discomfort, eating disorders, and physical discomfort.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.3
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• pp.125-134
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• 2021

Purpose : This study applies inspiratory muscle resistance exercise with aerobic exercise to smokers and nonsmokers and then determines whether subjects' breathing functions (FVC, FEV1) are increased and how much effect smoking has on the difference in the increase of breathing functions between the two groups. Methods : For this experiment, 26 male adults were selected and randomly allocated to the smoker group (n=13) and nonsmoker group (n=13). The smokers and nonsmokers performed the inspiratory muscle resistance exercise with aerobic exercise three times a week for four weeks. Regarding the breathing functions, the forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were measured three times: week 0, week 2, and week 4. The aerobic exercise was performed using a stationary bicycle with 8 difficulty levels. The inspiratory muscle resistance exercise was performed using Power Breathe with 10 resistance levels. Results : The study found that the FVC and FEV1 values of the smoker group decreased slightly after four weeks of inspiratory muscle resistance exercise with aerobic exercise. In other words, the difference was not statistically significant. In contrast, the FVC and FEV1 values of the nonsmoker group increased by a statistically significant amount. In addition, the intergroup comparison of the average increases in FVC and FEV1 values showed statistically significant differences. Conclusion : The results of this study show that when inspiratory muscle resistance exercise with aerobic exercise was performed, the increase in the breathing functions of nonsmokers was higher than that of smokers. This confirms that, within the parameters of the study, smoking had a negative effect on the increase of breathing functions. This suggests that quitting smoking must be considered as an essential factor when applying a breathing physiotherapy or a breathing function improvement program in clinical settings

• Journal of Korean Academy of Nursing
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• v.53 no.1
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• pp.129-143
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• 2023

Purpose: This study aimed to examine the mediating effects of clinical nurses' job crafting on organizational effectiveness based on the job demands-resources model proposed by Bakker and Demerouti (2017). Methods: The participants consisted of 393 nurses working in nursing units of a tertiary general hospital located in Cheongju region. The data, collected using questionnaire from August 9 to August 20, 2021, were analyzed using SPSS 23.0 and AMOS 27.0. Results: The goodness-of-fit (GoF) test results on the modified model (χ² = 2.7, GFI = .94, SRMR = .03, RMSEA = .06, NFI = .92, CFI = .94, TLI = .92, AGFI = .90), indicated that the GoF index satisfied the recommended level. Regarding the effects of each variable on organizational effectiveness, job crafting showed statistically significant direct (β = .48, p < .001), indirect (β = .23, p < .001), and total effects (β = .71, p < .001). Burnout showed statistically significant direct effect (β = - .17, p < .001). Work engagement showed statistically significant direct (β = .41, p < .001) and total effects (β = .41, p < .001). The factors explaining organizational effectiveness were job crafting, burnout, and work engagement, which had an explanatory power of 76.7%. Conclusion: Nurses' job crafting is an important mediating factor for enhancing the organizational effectiveness of nursing organizations. Hospitals should develop job-crafting success cases and related education and training programs as a strategy for enhancing the job crafting of nurses and, consequently organizational effectiveness.

• Journal of Energy Engineering
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• v.29 no.2
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• pp.68-78
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• 2020

According to the new climate change agreement, technology development to reduce greenhouse gases is actively conducted worldwide, and research on energy efficiency improvement in the field of power generation and transmission and distribution is underway [1,2]. Economic analysis of the operation method of storing and supplying surplus electricity using energy storage devices, and using energy storage devices as a frequency adjustment reserve power in regional cogeneration plants has been reported as the most profitable operation method [3-7]. Therefore, this study conducted an economic analysis for the installation of energy storage devices in the combined heat and power plant in the Czech Republic. The most important factor in evaluating the economics of battery energy storage devices is the lifespan, and the warranty life is generally 10 to 15 years, based on charging and discharging once a day. For the simulation, the ratio of battery and PCS was designed as 1: 1 and 1: 2. In general, the primary frequency control is designed as 1: 4, but considering the characteristics of the cogeneration plant, it is set at a ratio of up to 1: 2, and the capacity is simulated at 1MW to 10MW and 2MWh to 20MWh according to each ratio. Therefore, life was evaluated based on the number of cycles per year. In the case of installing a battery energy storage system in a combined heat and power plant in the Czech Republic, the payback period of 3MW / 3MWh is more favorable than 5MW / 5MWh, considering the local infrastructure and power market. It is estimated to be about 3 years or 5 years from the simple payback period considering the estimated purchase price without subsidies. If you lower the purchase price by 50%, the purchase cost is an important part of the cost for the entire lifetime, so the payback period is about half as short. It can be, but it is impossible to secure profitability through the economy at the scale of 3MWh and 5MWh. If the price of the electricity market falls by 50%, the payback period will be three years longer in P1 mode and two years longer in P2 and P3 modes.

• Korean Journal of Agricultural and Forest Meteorology
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• v.25 no.3
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• pp.226-235
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• 2023

This study aimed to supplement the shortcomings of the Multiple-sensor-based Frost Observation System (MFOS). The developed frost observation system is an improvement of the existing system. Based on the leaf wetness sensor (LWS), it not only detects frost but also functions to predict surface temperature, which is a major factor in frost occurrence. With the existing observation system, 1) it is difficult to observe ice (frost) formation on the surface when capturing an image of the LWS with an RGB camera because the surface of the sensor reflects most visible light, 2) images captured using the RGB camera before and after sunrise are dark, and 3) the thermal infrared camera only shows the relative high and low temperature. To identify the ice (frost) generated on the surface of the LWS, a LWS that was painted black and three sheets of glass at the same height to be used as an auxiliary tool to check the occurrence of ice (frost) were installed. For RGB camera shooting before and after sunrise, synchronous LED lighting was installed so the power turns on/off according to the camera shooting time. The existing thermal infrared camera, which could only assess the relative temperature (high or low), was improved to extract the temperature value per pixel, and a comparison with the surface temperature sensor installed by the National Institute of Meteorological Sciences (NIMS) was performed to verify its accuracy. As a result of installing and operating the MFOS v2, which reflects these improvements, the accuracy and efficiency of automatic frost observation were demonstrated to be improved, and the usefulness of the data as input data for the frost prediction model was enhanced.

• Journal of Korea Water Resources Association
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• v.44 no.7
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• pp.553-563
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• 2011

According to the improvement of computer's performance, the development of Geographic Information System (GIS), and the activation of offering information, a distributed model for analyzing runoff has been studied a lot in recently years. The distribution model is a theoretical and physical model computing runoff as making target basin subdivided parted. In the distributed model developed by this study, the volume of runoff at the surface flow is calculated on the basis of the parameter determined by landcover data and a two-dimensional diffusion wave equation. Most of existing runoff models compute velocity and discharge of flow by applying Manning-Strickler's mean velocity equation and Manning's roughness coefficient. Manning's roughness coefficient is not matched with dimension and ambiguous at computation; Nevertheless, it is widely used in because of its convenience for use. In order to improve those problems, this study developed the runoff model by applying not only Manning-Strickler's equation but also Chezy's mean velocity equation. Furthermore, this study introduced a power law of exponential friction factor expressed by the function of roughness height. The distributed model developed in this study is applied to 6 events of fan-shape basin, oblong shape test basin and Anseongcheon basin as real field conditions. As a result the model is found to be excellent in comparison with the exiting runoff models using for practical engineering application.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.8 no.4
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• pp.243-248
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• 2015

Since phase noise is one of the most important parameters in the design of microwave oscillators, several methods have been proposed to reduce the phase noise. These methods have focused on improving the quality factor of resonators, which result in low phase noise oscillators. Dielectric resonators have been widely used for low phase noise in microwave oscillators due to their high quality factor. However this cannot be used in MMIC oscillators because they have a 3D structure. In this paper, to overcome this problem a novel resonator using open ring type DGS is proposed for improvement of phase noise characteristics that is weak point of oscillator using planar type microstrip line resonator, and oscillator for 5.8GHz band is designed using proposed DGS resonator. The open ring type DGS resonator is composed of DGS cell etched on ground plane under $50{\Omega}$ microstrip line. At the fundamental frequency of 5.8GHz, 6.1dBm output power and -82.7 dBc@100kHz phase noise have been measured for oscillator with ring type DGS resonator. The phase noise characteristics of oscillator is improved about 96.5dB compared to one using the general ${\lambda}/4$ microstrip resonator.