• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.8
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• pp.1172-1180
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• 2017

This study analyzed competition in peak load plants between CCGT and GT instead of competition between base and peak load plants like in previous studies. In common overseas power markets, CCGT and GT claim certain market shares as peak load plants with the latter boasting a high utilization rate as reserve plants. In South Korea, however, there has been no introduction of GT in the market that opened in 2001 with no analysis cases of GT's economy as a peak load plant. The current power market of South Korea is run on the cost-based pool, which allows for no price spikes. Since the capacity payment criteria for compensations for missing money are set based on GT generators, the power market uses GT generators as marginal plants. The purposes of this study were to analyze the competitive edge of GT generators as peak load plants in the domestic power market of South Korea and identify the causes of GT's failure in market entry, thus assessing the adequacy of market signals in the domestic power market.

• Korean Journal of Adult Nursing
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• v.18 no.4
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• pp.660-667
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• 2006

Purpose: The purpose of this study was to investigate the effects of 12-week brisk walking and brisk walking plus diet program on C-Reactive Protein(CRP) in middle-aged obese hypertriglycemic($triglyceride{\geq}150mg/d{\ell}$) Korean women. Method: The subjects were 16 obese ($BMI{\geq}25$) hypertriglycemic middle-aged women (7 for brisk walking group, 9 for brisk walking plus diet group) who participated in a health promotion program at one public health center. Initially the brisk walking intervention consisted of walking for 20 minutes/day at an intensity of 40 to 50% of heart rate reserve(HRR) for 3 days/week and progressed to 50 minutes/day, 60 to 70% of their HRR, and 6 days/week. The diet intervention consisted of 60 minutes of group education and 20 to 30 minutes of individual counseling with a nutritionist every week. Data were analyzed with SPSS PC program. Results: There was no significant reduction in CRP levels in both brisk walking (Z=-1.70, p=0.088) and brisk walking plus diet group(Z=-0.31, p=0.752). In brisk walking only group, CRP levels were increased after the intervention. Conclusion: Brisk walking could increase the level of CRP when it is in the course of progression and diet could decrease the acute phase inflammatory response.

• Journal of Electrical Engineering and Technology
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• v.13 no.6
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• pp.2245-2253
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• 2018

With the increase of electrical consumption and the unbalance of power demand and supply, power reserve rate is getting smaller and also the reliability of the power supply is getting deteriorated. Under this circumstance, the electrical energy storage (EES) System is considered as one of essential countermeasure for demand side management. This paper proposes efficient evaluation algorithms of multiple functions for EES systems, especially the secondary battery energy storage systems, in the case where they are interconnected with the power distribution systems. It is important to perform the economic evaluation for the new energy storage systems in a quantitative manner, because they are very costly right now. In this paper, the multiple functions of EES systems such as load levelling, effective utilization of power distribution systems and uninterruptible power supply are classified, and then the quantitative evaluation methods for their functions are proposed. From the case studies, it is verified that EES systems installed at distribution systems in a dispersed manner have multiple functions involved with direct and indirect benefits and also they can be expected to introduce to distribution systems with respects to economical point of view.

• Journal of Applied Tourism Food and Beverage Management and Research
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• v.9
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• pp.163-185
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• 1998

It is expected that marketing environment of the hotel industry will change much this year. Hotels should make strategic marketing activities to cope with the rapid change of the environment positively. With the case study of marketing activities for American market of "L" Hotel, a deluxe hotel in Seoul, this study is to present the ways of improving marketing activities of a tourist hotel. U.S.A market has been emerging as the most important market in deluxe hotels with strong value of U.S. dollar currency. To get more Ameriean staying guests. hotels had better make effortis in American market as follow. First, hotels should select corporate market as main target market in U.S.A market. Second, hotels should make preferred corporate rate contracts with corporate travel departments of corporate accounts as their house agents Third, hotels should recognize Global Distribution System as major eservation network in U.S.A Fourth, hotels should advertise effectively in G.D.S in order that agents may reserve the hotel with its visual information. Fifth, hotels had better make the most use of three branch offices of K.N.T.O and sale offices of their affiliated reservation system to get useful information on corporates and travel agents.el agents.

• Nuclear Engineering and Technology
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• v.45 no.5
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• pp.589-596
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• 2013

In a pressurized heavy water reactor, following loss of the primary coolant, severe core damage would begin with the depletion of the liquid moderator, exposing the top row of internally-voided fuel channels to steam cooling conditions on the inside and outside. The uncovered fuel channels would heat up, deform and disassemble into core debris. Large inventories of water passively reduce the rate of progression of the accident, prolonging the time for complete loss of engineered heat sinks. The efficacy of available backup and ultimate heat sinks, available in a CANDU 6 reactor, in mitigating the consequences of a prolonged station blackout scenario was analysed using the MAAP4-CANDU code. The analysis indicated that the steam generator secondary side water inventory is the most effective heat sink during the accident. Additional heat sinks such as the primary coolant, moderator, calandria vault water and end shield water are also able to remove decay heat; however, a gradually increasing mismatch between heat generation and heat removal occurs over the course of the postulated event. This mismatch is equivalent to an additional water inventory estimated to be 350,000 kg at the time of calandria vessel failure. In the Enhanced CANDU 6 reactor ~2,040,000 kg of water in the reserve water tank is available for prolonged emergencies requiring heat sinks.

• Women's Health Nursing
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• v.8 no.1
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• pp.55-68
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• 2002

While the survival rate of preterm infants and employment rates of mothers with infants have been dramatically increasing, little is known about the impact of maternal employment and having premature infants on maternal health recovery after delivery. The purpose of this longitudinal study was to examine differences in postpartum health by mother's employment and infant's prematurity over time during the first 3 months postpartum. The study used a longitudinal design and was secondary data analysis from a large study. A convenience sample of 132 mothers was recruited with mothers who had fullterm or preterm infants through the postpartum unit. They were followed up for 3 times (at 1-2 days, 6 weeks, and 3 months) during the first 3 months postpartum period. Level of fatigue and hysical symptoms were indicators for postpartum physical health; Positive affect and negative affect were assessed for postpartum mental health, and role functional status after childbirth was for role performance. Finding indicated that health indicators changed significantly over time but there was no main or interaction effect for maternal employment status. There were main effects of infant's prematurity on positive affect, negative affect, and role functional status (self-care and social and community activities). This study enhanced the understanding of postpartum health of mothers with preterm infants as well as those with fullterm infants during the postpartum period.

• Journal of the Korean Applied Science and Technology
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• v.34 no.3
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• pp.587-594
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• 2017

The purpose of this study was to investigate the effect of rope skipping and band exercise on GH, IGF-1 and metabolic syndrome risk factors in female obese middle school students. Twenty female obese middle school students(%BF > 30%) were randomly assigned to a exercise group(EX, n=10) or control group(CON, n=10). The exercise group has performed rope skipping and band exercise for 12 weeks, 3time per week. Exercise intensity was increased gradually, from 40% to 70% of Heart Rate Reserve(HRR) and Rating of Perceived Exertion(RPE) 11-15. GH, IGF-1 and metabolic syndrome rist factors were GH, IGF-1 and metabolic syndrome risk factors were measured pre- and post-exercise program including rope skipping and band exercise. Levels of GH and IGF-1 were significantly increased (p<.01 and p<0.001, respectively) in exercise group after 12 weeks of exercise training. WC and TG were significantly decreased(p<.01) in exercise group after 12 weeks of training. HDL-C was significantly increased(p<.05) in exercise group after 12 weeks of training. In conclusion, rope skipping and band exercise were effective exercise program in improving GH, IGF-1 and metabolic syndrome risk factors in female obese middle school students.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.3
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• pp.358-364
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• 1996

Recently, much power demand from domestic power consumer is weakening the allowable power reserve margin in summer, especially at midday for one day due to a steep increase of air cooling loads such as air conditioner. Therefore solar airconditioning system can'be considered as one of the best remedies to meet the increase of peak power. Generally in solar air conditioning system, the diode rectifier is used to build up DC link voltage from AC source. The diode rectifier is simple and cheap but it brings out the problems of low power factor and plentiful harmonics at the AC source. Also It can derate the utilization rate of solar energy because the reverse of power flow cannot be made. Hence, in this paper to overcome the peak power problem in summer and to endure good AC input characteristics, solar air conditioning system using the PWM converter is proposed. As results, obtained are the characteristics of the PWM converter such as low distorted current waveform, high power factor and bidirectional power control. And also the stability of proposed system is verified by examining the dynamics of step load change and power reversal testing. (author). refs., figs., tabs.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.4
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• pp.717-725
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• 2011

In the power system with an electric storage system that can increase utilization rate of the source of such new renewable energy, this paper introduces the approach on the daily unit commitment scheduling that determines simultaneously optimum operational condition and output of thermal generators and electric storage device. The unit commitment is one of the most important issues in economic operation and security of short-term operational plan of the power system. It is to determine on/off status of generator to minimize operational cost during the given period. The committed generator should satisfy various operational limitation such as estimated demand by system, spinning reserve condition within minimum operational cost. In order to determine on/off or charge/discharge/idle condition and output level of units and electric storage system, the MILP(Mixed Integer Linear Programming) is suggested. The proposed approach is the mixed method between LP(Linear Programming) and IP(integer programming) which seeks the value of real number and integer that maximize or minimize function objective within given condition. The daily unit commitment problem with the electric storage system is applied to MILP algorithm through linearization and formulation process. The proposed approach is applied to the test system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.5
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• pp.601-610
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• 2018

The purpose of this paper is to establish a new optimum Generator Maintenance Scheduling(GMS) considering renewable energy generator. In this paper, the total renewable energy generation is estimated using hourly capacity factor of renewable energy generator. The GMS was optimized with the objective function of maximizing the minimum reserve rate, minimizing the probabilistic production cost, minimizing the loss of load expectation, and minimizing $CO_2$ emissions. In the case study of this paper, GMS considering renewable energy and GMS not considering renewable energy are shown by each objective function. And it shows scenarios of the reliability, the environmental and economical factors when two nuclear power plants inputted and ten coal thermal power plants shut downed respectively.