• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.3
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• pp.9-19
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• 2015

Internal air temperature of greenhouse is an important variable that can be influenced by the complex interaction between outside weather and greenhouse inside climate. This paper focuses on a data-based model approach to predict internal air temperature of the greenhouse. External air temperature, solar radiation, wind speed and wind direction were measured next to an experimental greenhouse supported by the Electronics and Telecommunications Research Institute and used as input variables for the model. Internal air temperature was measured at the center of three sections of the greenhouse and used as an output variable. The proposed model consisted of a transfer function including the four input variables and tested the prediction accuracy according to the sampling interval of the input variables, the orders of model polynomials and the time delay variable. As a result, a second-order model was suitable to predict the internal air temperature having the predictable time of 20-30 minutes and average errors of less than ${\pm}1K$. Afterwards mechanistic interpretation was conducted based on the energy balance equation, and it was found that the resulting model was considered physically acceptable and satisfied the physical reality of the heat transfer phenomena in a greenhouse. The proposed data-based model approach is applicable to any input variables and is expected to be useful for predicting complex greenhouse microclimate involving environmental control systems.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.5
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• pp.82-88
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• 2001

The EGR is needed fur one of various strategies to reduce NOx emission. But to get the proper EGR rate, the intake and exhaust system become complicated. That is a reason why we consider using the internal EGR system. The internal EGR is a system which reduces NOx by controling the residual gas fraction in cylinder by changing valve timing and valve lift of intake and exhaust. In this paper, characteristics of volumetric efficiency and residual gas fraction in cylinder were investigated for various engine speeds by changing valve timing and valve lift of intake and exhaust in the 4 stroke-cycle diesel engine. Volumetric efficiency and residual gas fraction were calculated by the method of characteristics. As the results, residual gas fraction and volumetric efficiency in cylinder by variable valve timing were visualized.

• Nuclear Engineering and Technology
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• v.31 no.3
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• pp.257-266
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• 1999

A simplified statistical methodology is developed in order to both reduce over-conservatism of deterministic methodologies employed for PWR fuel rod internal pressure (RIP) calculation and simplify the complicated calculation procedure of the widely used statistical methodology which employs the response surface method and Monte Carlo simulation. The simplified statistical methodology employs the system moment method with a deterministic approach in determining the maximum variance of RIP The maximum RIP variance is determined with the square sum of each maximum value of a mean RIP value times a RIP sensitivity factor for all input variables considered. This approach makes this simplified statistical methodology much more efficient in the routine reload core design analysis since it eliminates the numerous calculations required for the power history-dependent RIP variance determination. This simplified statistical methodology is shown to be more conservative in generating RIP distribution than the widely used statistical methodology. Comparison of the significances of each input variable to RIP indicates that fission gas release model is the most significant input variable.

• Structural Engineering and Mechanics
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• v.5 no.5
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• pp.587-598
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• 1997

A numerical model for masonry is proposed by following an internal variable approach originally developed in the field of elastic-plastic analysis. The general features of the theoretical framework are discussed by focussing on finite element models applicable to incremental elastic-plastic problems. An extremum property is derived and its implications in terms of convergence for convenient algorithms are briefly discussed, by including the case of softening materials and damage effects. Next, a numerical model is presented, which is suitable for masonry, can be developed according to the same internal variable formulation and enjoys similar properties. Some numerical results are presented and compared with the response of a masonry shear wall subjected to pseudodynamic tests.

• Tuberculosis and Respiratory Diseases
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• v.73 no.5
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• pp.282-287
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• 2012

Broncholiths are defined as calcified materials that occur in a tracheobronchial tree or in a cavity communicating with that. Broncholith has variable clinical features. The therapeutic options to remove broncholiths are so variable that clinicians need to select the most safe and effective methods by mass size, mobility, and location. As yet, there is no consistent guideline removing a broncholith. We report 2 successful cases of removing a fixed broncholith by flexible bronchoscopy guided cryoadhesion. With repeated technique of thawing and freezing with cryoprobe, we could extract the fixed broncholith safely. This method is promising as a way to remove broncholith in the future.

• Journal of the Korean Home Economics Association
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• v.35 no.5
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• pp.163-175
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• 1997

This study investigated the relationship between mother's verbal control modes and children's social competency, the relationship between mother's verbal control modes and children's internal-external control, and the relationship between children's internal-external control and children's social competency. The subjects of this study were 157 boys and 144 girls attending elementary schools and their mothers in Busan. Lee's(1993) questionnaire on mother's verbal control modes, the modified version of Nowicki and Strickland's CN-SIE on internal-external control and Choi's(1992) questionnaire on social competence were used. The results were as follows: 1) The mothers control their children mostly by position-oriented mode. And mother's imperative mode for boys differed significantly from that for girls. Boys perceived mother's verbal control mode as more imperative. 2) There were significant negative correlations between mother's imperative mode and boy's social competency, between mother's imperative mode and boy's anxiety, and between mother's imperative mode and boy's internal-external control and boy's social competency, and between boy's internal-external control and boy's leadership. There were significant correlations between mother's position-oriented mode and girl's leadership, between mother's position-oriented mode and girl's, affection on parents, between mother's position-oriented mode and girl's internal-external control. There were significant negative correlations between girl's internal-external control and girl's anxiety. 3) Children's internal-external control was the predictor variable influencing on children' social competency, children's leadership. Children's sex was the predictor variable influencing on children' anxiety. And the mother's imperative mode and the mother's position-oriented mode were the predictor variables influencing on children' affection on parents.

• Korean Journal of Food Science and Technology
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• v.23 no.2
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• pp.157-160
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• 1991

Copper constantan thermocouples connecting to a recording potentiometer were inserted at the center of the patties and the samples were fried. In general, the internal temperature of the patty samples increased approximately $11.1^{\circ}C$ after the samples were removed from the fryer. The desired internal temperature and maximum internal end-point temperature, at different frying temperatures, can be obtained by adjusting the frying time. The yields of the patties decreased as maximum internal end-point temperature increased or as frying time increased. The internal temperature and maximum internal end-point temperature of the patty samples at three frying temperatures were predicted using polynominal regression of a third-order model with one independent variable, frying time. Polynominal regression of a second-order model with maximum internal end-point temperature as the independent variable was used to predict frying yields at three frying temperatures.

• Tuberculosis and Respiratory Diseases
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• v.43 no.3
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• pp.449-454
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• 1996

Functional upper airway obstruction due to vocal cord dysfunction is being increasingly recognized and has been variously described as "Munchausen's stridor", "Emotional laryngeal wheezing", "Nervous asthma". It's features are symptoms of acute reversible recurrent dyspnea associated with an inspiratory stridor, normal anatomy of the upper airway, demonstration of variable severe exthrathoracic upper airways obstruction with pathologic adduction of the vocal cord at bronchoscopy. The patients with this condition are frequently misdiagnosed as asthma and the diagnosis is often delayed. So they can present a serious medical problem and are exposed to the complication of treatment and investigation. We report a case of functional upper airway obstruction due to vocal cord dysfunction who showed paradoxical vocal cord motion at bronchoscopy and typical features of variable exthrathoracic obstruction on Flow-volume loop during a symptomatic period.

• Tuberculosis and Respiratory Diseases
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• v.86 no.3
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• pp.158-165
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• 2023

Asthma is a chronic inflammatory airway disease that is characterized by variable airflow obstruction. The Korean Asthma Study Group of the Korean Academy of Tuberculosis and Respiratory Diseases has recently updated the Korean Asthma Guideline. This review summarizes the updated Korean Asthma Guideline. Asthma prevalence is increasing worldwide, and in Korea. Variable airflow obstruction can be confirmed by bronchodilator response or other tests, and should be established prior to the controller medication. A low-dose inhaled corticosteroid-formoterol is used to alleviate symptoms in all treatment step, and it can be used as a controller as well as reliever in steps 3-5. This approach is preferred, because it reduces the risk of severe exacerbations, compared to the use of short-acting β2-agonist as reliever. In severe asthma, phenotype/endotype based on the underlying inflammation should be evaluated. For type 2 severe asthma, the biologics should be considered.

• Journal of the Korean institute of surface engineering
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• v.13 no.4
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• pp.211-220
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• 1980

Internal stress of electrodeposited metals affect physical and mechanical characteristics of deposits. Internal stress of nickel deposits was reviewed intensively. Important outcomes are as follows. Substrate have an important effect on internal stress of electrodeposit. Origin of its internal stress could be explained mismatch of crystal lattice and coalescence of crystallites. When surface cleaning is not satisfying, instantaneous stress is low but the electrodeposited layer being thickened increasingly stress become to high and peeling phenomenon occurs. Effect of current density and temperature on internal stress is variable. Internal stress increases rapidly at pH 5 and above because of codepositing colloidal materials caused hydrolysis. Concentrations of nickel ion and $H_3BO_3$ ion affect little on internal stress and solution which contains impurities tend to increase stress. Especially impurities of $H_2O_2$ and iron ion have a great effect on internal stress. Additives are divided in two kind. One is increasing tensile stress another is increasing compressive stress. Concentrations of additives have a great effect on internal stress.