• East Asian mathematical journal
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• v.30 no.1
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• pp.23-29
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• 2014

To solve inefficient spectrum usage problem under current static spectrum management policy, various kinds of dynamic spectrum access strategies have appeared. Myopic policy, which maximizes immediate throughput, is a simple and robust strategy with reduced complexity. In this paper, we present a simple mathematical model to evaluate the saturation throughput and medium access delay of a myopic policy in the presence of multiple channels.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.560-563
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• 2006

LED is promising for the application of specialty illumination. Thiscolor management system, V-core, with LED light sources and the structure of V-core for LCoS projector has been proposed to improve the primary saturation, uniformity and contrast. We designed the high efficient LED modules for high brightness requirement. The LED module can operate in narrow-direction indicator, $12^{\circ}$.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.2
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• pp.130-137
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• 2018

In the construction industry, research on alkali activated cement using fly ash or blast furnace slag fine powder has been published in Korea and abroad as a way to reuse industrial byproducts without using cement at all and to obtain economical effects at the same time. the purpose of this paper is to evaluate the effect of the ratio and coefficient of hydration ratio and lime saturation degree on the strength of alkali activated slag cement by chemical quantitative analysis of alkali activated slag cement used in the management of existing portland cement. as a result, it was confirmed that the ratio and coefficient of hydration ratio and lime saturation are all within a certain range.

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.4 no.2
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• pp.88-91
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• 2008

A female patient (14 years-old) with mental retardation was scheduled for ambulatory general anesthesia to treat peri-apical abscess and multiple dental caries. She had got cleft palate plasty at 5 years, but there was no past history of difficulty airway during general anesthesia or airway obstruction. Following induction of anesthesia using an inhalational anesthetic technique, conventional naso-tracheal intubation was tried. However, with conventional intubation technique we could not insert tube. And following several trial of intubation with laryngoscope, she developed an upper airway obstruction. Her lungs could not be ventilated using a facial mask and oxygen saturation was decreased. A #3 laryngeal mask airway (LMA) was inserted immediately, which allowed us to ventilate her lungs and restore the oxygen saturation. And dental treatment was carried out under LMA insertion successfully.

• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.4
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• pp.772-781
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• 1998

The purpose of this study was to assess the sedative effect of intranasal spray with midazolam for management of the uncooperative 20 children aged from 24 months to 92 months who required extensive treatment. The patients were given randomly a dose of 0.2mg/kg of intranasal placebo, intranasal spray with midazolam, and intranasal drop with midazolam. All the children were restrained in a pediwrap and were monitored with pulse oximeter for assessing the pulse rate and peripheral oxygen saturation. According to Fukuta's behavior rating scale, behavior was checked for evaluation of the clinical sedative effect. The obtained results were as follows: 1. Behavior score of intranasal spray with midazolam was lower than intranasal drop with midazolam(P<0.01). 2. Pulse rate was a significant change as a function of dental procedure(P<0.001), however the peripheral oxygen saturation was not influenced significantly by either adiministration route of drug or dental procedure. Clinically, intranasal spray with midazolam were safe and effective sedation in young children undergoing pediatric dental procedures.

• Child Health Nursing Research
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• v.4 no.2
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• pp.245-254
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• 1998

Prematurity is the main cause for respiratory disorders in neonates. The goal in respiratory management is to maintain respiration with adequate oxygenation. Chest vibration(CV) prior to on dotracheal suctioning(ETS) has been arbitrarily applied to ventilated premature infants without the scientific evaluation of its safety and efficacy. A repeated measure within subjects experimental study was conducted to investigate the effects of CV prior to 875 on oxygenation and lung secretions in twenty-one ventilated premature infants. The independent variable was the type of research protocol, the control type (275 without C.V) and t he intervention(ETS with CV). The dependent variables were oxygen saturation(SpO₂), heart rate (HR), measured by pulse oximeter, and the amount of lung secretions measured in gram. The results showed there was no difference in SpO₂ responses regardless CV employed before ETS. But there was a significant difference in HR responses between the control and the intervention, even without clinical significance. There was a significant difference in the amount of lung secretions retrieved during ETS with CV, compared to ETS without CV. This study suggested the safety of CV by demonstrating no clinically significant changes in SpO₂ and HR in premature infants. The efficacy of CV could be supported by the increases in the amount of sputum during ETS with CV compared to ETS without CV in premature infants.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.2
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• pp.114-121
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• 2013

In order to estimate the efficiency of an evaporative heat exchanger having mini channel, the equations to calculate heat exchanger properties, those are air temperatures and water temperatures etc, are derived from the governing equations based on the Navier-Stokes equation, even though there are several assumptions to make problem simplify. There are three heat transfer zones at the mini channel heat exchanger depending on the water condition. So, there are three governing equations and solutions to calculate the properties. As the results of this study, the equations to calculate a saturation point and a dry point are derived to evaluate an evaporative heat exchanger having micro channel. It is supposed to predict and evaluate the performance of a mini channel heat exchanger with evaporation of liquid.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.157-165
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• 2016

Among high-tech products, the mobile phone has experienced a rapid rate of innovation and a shortening of its product life cycle. The shortened product life cycle poses major challenges to those involved in the creation of forecasting methods fundamental to strategic management and planning systems. This study examined whether the best model applies to the entire diffusion life span of a mobile phone. Mobile phone sales data from a specific mobile service provider in Korea from March of 2013 to August of 2014 were analyzed to compare the performance of two S-shaped diffusion models and two non-linear regression models, the Gompertz, logistic, Michaelis-Menten, and logarithmic models. The experimental results indicated that the logistic model outperforms the other three models over the fitted region of the diffusion. For forecasting, the logistic model outperformed the Gompertz model for the period prior to diffusion saturation, whereas the Gompertz model was superior after saturation approaches. This analysis may help those estimate the potential mobile phone market size and perform inventory and order management of mobile phones.

• Journal of the Korean Institute of Landscape Architecture
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• v.18 no.3 s.39
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• pp.115-135
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• 1990

The purpose of this study was to suggest an improvement proposal for colors in urban environment with special regard to the surface color and their situations of apartment buildings in Seoul. For this goal, 167 cases of different color types of apartment buildings were surveyed. And, the survey was performed in the view of color by areas, by localtion, by builder, by paint year, by built year, by appearance of building, and by surface texture to prove the influencing factors on the surface colors. These collected data analyzed and compared with the existing studies to find out the changing trend of colors. The results are as follows : 1) The use of neutral gray($26.4{\%}$) and warm color(YR, Y, GY; 56.4%) were dominant and the usage trend of higher 'value'(87.4%) and lower 'saturation'(73.0%) was obvious. Especially, the use of PB and P was noticeable. 2) In comparing the existing studies, the changing trend in the surface color pattern was found. That is, neutral gray was used dominantly in 1970's, warm color(YR, Y)in the middle of 1980's. In the end of 1980's, warm color were also used dominantly same as before and GY, PB, P were used noticeably with some rising tendency of higher 'value' and lower 'saturation' was obvious. 3) The results of analysis by localtion shows that the different color groups might exist in Seoul city. Neutral gray and YR were dominant in zone I. Warm colors(YR, Y, GY)were prevailed in zone II, III, IV. In zone V, many colors were evenly used. In zone VI, middle values at warm color were dominant. Progressively, these color groups with further study could be considered in the color management in urban environment possibly. 4) Surface color of apartment buildings were different from their builders. 5) Concerned with the painted year, the use of higher 'value' and lower 'saturation' was increased gradually with the change of times. 6) the analysis by the built year revealed that the 'value' of surface colors on the old buildings was lower than that of the new ones. 7) The 'value' of colors on the surface with texture was higher than that of the surface without texture. 8) In the combination of two colors, the use of 'value' with difference at the same 'hue' was found harmonions in many cases, but the 'saturation' in usage was included in the ambiguity (Moon & Spencer's term). The ambiguity in color harmony should be improved in the near future.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.324-327
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• 1996

In this paper, the affecting factors of the access demand for the cellular service are derived, and the access demand function of the cellular service is estimated. The results obtained in this study are as follows: First, the price (access charge) and the income elasticities of cellular services there exists a network externality in cellular communication services. Third, the technological capability of the service provider has played an essential role in expanding the size of subscribers. Fourth, the access demand of cellular communication service is not sensitive to the usage charge. According to the above results, it can be inferred that if the access charge is lowered, the number if subscribers will increase to the critical mass, and then the cellular communication market will grow up to a saturation point naturally.