• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.2
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• pp.137-147
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• 2004

Sea surface cooling (SSC) with the passage of typhoons is examined in the East Sea using the Japan Meteorological Agency buoy data $(37^{\circ}45'N,\;134^{\circ}23'E)$ during 1983-2000 and a three-dimensional primitive equation model (the Princeton Ocean Model). Forty typhoons in this period induced the SST decrease ranging from about $-0.5^{\circ}C\;to\;-4.3^{\circ}C.$ Intense SSC $(<-2^{\circ}C)$ occurs with typhoons that passed mainly through the left-hand side of the buoy station. The model is implemented to examine a physical process of SSC with a typical-track typhoon in the northwestern Pacific $(24^{\circ}N\;to\;52^{\circ}N).$ The model well reproduces prominent features in the observation and addresses how it happens; SSC is induced mainly by momentum mixing effect stirred with the typhoon rather than upwelling.

• Journal of Digital Convergence
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• v.17 no.12
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• pp.109-115
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• 2019

The purpose of this study is to analyze the effect of Prior Sales change on R&D Costs and each detail item, and to analyze what decision managers make when changing sales. In order to conduct a more in-depth analysis as well as a one-period model of Anderson et al. (2003), which was used in previous studies, the two-period model of Banker et al.(2014) And analyzed the detailed items. As a result of the analysis, it is possible to confirm cost stickiness behavior only in the depreciation cost and others due to the limit of the model in the one period model. For a more in-depth analysis, the analysis of two-period model showed that labor costs and other items showed cost stickiness behavior when prior sales increased, but total R&D costs showed a anti-cost stickiness behavior. When prior sales decline, consigned service costs showed a cost stickiness behavior. This study is meaningful because it analyzed the effect of prior sales change on R&D cost behavior which were not performed in previous studies. Furthermore, we expect to be able to conduct more detailed research by sales and industry in future studies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.858-864
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• 2011

There is no standard model for a Stated Period Check and a Precise Safety Diagnosis to remove electric fire and shock in the university Lab and institute. Especially, the research for the Stated Period Check and the Precise Safety Diagnosis of the Lab related to electrical field is very weak currently, and it is very necessary to build a detail safety plan. This paper informs the specific standard guideline of the safety check list, method and equipment and it shows the way to evaluate safety grade too. This paper also provides the information of R&D process through the analysis of electrical safety check list of ordinary R&D Lab. It shows a new detail guideline to R&D Lab, and the new guideline removes existing problem and deliver the effective standard model to each R&D Lab. The standard model developed in this research adopts the clear guideline of each check list for the electrical environment of current R&D Lab. This standard model can be applied for every R&D Lab to detect routine safety check and detail safety check immediately. This Research will generally improve not only the effective safety check, but also the safety level for R&D Lab to prevent the electrical accidents.

• International Journal of Concrete Structures and Materials
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• v.9 no.4
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• pp.439-451
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• 2015

This study analyzed the isolation effect for a 15-story reinforced concrete (RC) building with regard to changes in the beam-column stiffness ratio and the difference in the vibration period between the superstructure and an isolation layer in order to provide basic data that are needed to devise a framework for the design of isolated RC buildings. First, this analytical study proposes to design RC building frames by securing an isolation period that is at least 2.5 times longer than the natural vibration period of a superstructure and configuring a target isolation period that is 3.0 s or longer. To verify the proposed plan, shaking table tests were conducted on a scaled-down model of 15-story RC building installed with laminated rubber bearings. The experimental results indicate that the tested isolated structure, which complied with the proposed conditions, exhibited an almost constant response distribution, verifying that the behavior of the structure improved in terms of usability. The RC building's response to inter-story drift (which causes structural damage) was reduced by about one-third that of a non-isolated structure, thereby confirming that the safety of such a superstructure can be achieved through the building's improved seismic performance.

• Journal of the korean Society of Automotive Engineers
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• v.14 no.5
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• pp.30-40
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• 1992

Spark knock obstructs any improvement in the efficiency and performance of an engine. As the knock mechanism of spark ignition engine, the detonation and the autoignition theory have been offered. In this paper, the knock model was established, which was able to predict the onset of knock and knock timing of spark ignition engine by the basis of autoignition theory. This model was a function of engine speed and equivalent air-fuel ratio. When this established knock model was tested from 1000rpm to 3000rpm of engine speed data, maximum error was crank angle 2 degrees between measured and predicted knock time. And the main results were as follows by the experimental analysis of spark knock in spark ignition engine. 1) Knock frequency was increased as engine speed increased. 2) Knock amplitude was increased as mass of end gas increased. 3) Knock frequency was occured above minimum 18% mass fraction of end gas.

• Journal of the Korean Society of Systems Engineering
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• v.8 no.2
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• pp.37-45
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• 2012

About 20 years have passed since Systems Engineering(SE) was introduced in Korea. KCOSE(Korean Council On Systems Engineering) and KOSSE(The Korean Society of Systems Engineering) were established during that period and Korean SE community has increased quantitatively. But We can not answer "Yes!" for the questions "Did Korean SE community increase qualitatively? and How about SE education or training?" Many participants at SE lecture classes said that they were not able to understand SE concept. I analyzed current SE lecture materials and then proposed new model of SE concept lecture for SE novices. The new model consists of Vee diagram, life cycle model, PMTE paradigm, technical review, SE sample and definition of SE. I expect that the proposed model will contribute to upgrade a quality of domestic SE education.

• Communications for Statistical Applications and Methods
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• v.11 no.2
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• pp.227-233
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• 2004

This paper presents our work on constructing a model that is intended to predict the probability of attrition at specified points in time among customers of an insurance company. There are some difficulties in building a data-based model because a data set may contain possibly censored observations. In an effort to avoid such kind of problem, we performed logistic regression over specified time intervals while using explanatory variables to construct the proposed model. Then, we developed a Cox-type regression model for estimating the probability of attrition over a specified period of time using time-dependent explanatory variables subject to changes in value over the course of the observations.

• Journal of Dental Anesthesia and Pain Medicine
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• v.20 no.2
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• pp.73-81
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• 2020

Background: The international organization for standardization (ISO) 80601-2-61 dictates that the accuracy of a pulse oximeter should be assessed by a controlled desaturation study. We aimed to characterize the relationship between the fraction of inspired oxygen (FiO₂) and peripheral oxygen saturation (SpO₂) using a turnover model by retrospectively analyzing the data obtained from previous controlled desaturation studies. Materials and Methods: Each volunteer was placed in a semi-Fowler's position and connected to a breathing circuit to administer the hypoxic gas mixture containing medical air, oxygen, nitrogen, and carbon dioxide. Volunteers were exposed to various levels of induced hypoxia over 70-100% arterial oxygen saturation (SaO₂). The study period consisted of two rounds of hypoxia and the volunteers were maintained in room air between each round. FiO₂ and SpO₂ were recorded continuously during the study period. A population pharmacodynamic analysis was performed with the NONMEM VII level 4 (ICON Development Solutions, Ellicott City, MD, USA). Results: In total, 2899 SpO₂ data points obtained from 20 volunteers were used to determine the pharmacodynamic characteristics. The pharmacodynamic parameters were as follows: k_out = 0.942 1/min, Imax = 0.802, IC₅₀ = 85.3%, γ = 27.3. Conclusion: The changes in SpO₂ due to decreases in FiO₂ well explained by the turnover model with inhibitory function as a sigmoidal model.

• Journal of Korean Society for Atmospheric Environment
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• v.26 no.2
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• pp.161-176
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• 2010

We examined high ozone episodes observed during the intensive measurement periods (11 May~21 June and 30 July~11 August 2009) in the Gulf of Gwangyang. During that period, there were a few events (or days) in which 1 hr averaged ozone concentrations were greater than 100 ppbv. The analysis of ozone budget and photochemical characteristics related to the ozone production was carried out using a photochemical box model. Ozone sensitivity to $NO_x$ and VOCs was also examined in the study area during the measurement period. Diurnal variation of ozone during the episodes was similar to that of odd hydrogen radicals ($HO_2,CH_3O_2$, and $RO_2$), suggesting significant correlation with photochemical production of ozone during the episodes. In general, ozone concentration in the study area during the measurement period was sensitive to VOCs, whereas ozone was sensitive to $NO_x$ under certain conditions. Ozone sensitivity assessment using a radical budget analysis and $NO_x$/VOCs-control strategy was consistent with that using indicator species ($H_2O_2/HNO_3$ ratio).

• Korean Journal of Agricultural and Forest Meteorology
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• v.7 no.3
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• pp.185-191
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• 2005

An accurate prediction of dormancy release and bud burst in temperate zone fruit trees is indispensable for farmers to plan heating time under partially controlled environments as well as to reduce the risk of frost damage in open fields. A thermal time-based two-step phenological model that originated in Italy was applied to two important grapevine cultivars in Korea for predicting bud-burst dates. The model consists of two sequential periods: a rest period described by chilling requirement and a forcing period described by heating requirement. It requires daily maximum and minimum temperature as an input and calculates daily chill units (chill days in negative sign) until a pre-determined chilling requirement for rest release is met. After the projected rest release date, it adds daily heat units (anti-chill days in positive sign) to the chilling requirement. The date when the sum reaches zero isregarded as the bud-burst in the model. Controlled environment experiments using field sampled twigs of 'Campbell Early' and 'Kyoho' cultivars were carried out in the vineyard at the National Horticultural Research Institute (NHRI) in Suwon during 2004-2005 to derive the model parameters: threshold temperature for chilling and chilling requirement for breaking dormancy. The model adjusted with the selected parameters was applied to the 1994-2004 daily temperature data obtained from the automated weather station in the NHRI vineyard to estimate bud burst dates of two cultivars and the results were compared with the observed data. The model showed a consistently good performance in predicting the bud burst of 'Campbell Early' and 'Kyoho' cultivars with 2.6 and 2.5 days of root mean squared error, respectively.