• 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.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.3
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• pp.285-289
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• 2013

The coastal area of Republic of Korea is very clean compared to other countries. In this reason, west coastal area of our country is a good place for breeding up a fish such as shrimp. In winter season, the heating system is required for preventing shrimp death caused by freezing in the farm. The heater in the heating system for fishery's farm is operated very severe combating corrosion due to high accumulation by feeding material and high temperature in heated sea water. Almost all manufactured heaters of STS 316L and Ti material are scrapped every year due to heavy corrosion such a general and crevice corrosion. For comparing the general and galvanic corrosion in new heater material, the test material of Zirconium (Zr), Titanium (Ti) and STS 316L are tested by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), current density-time methods and microscopic examination in a 3.5% NaCl solution. The corrosion potential (Ecor) measured by potentiodynamic polarization for Zr, Ti and STS 316L reveals -198, -250 and -450mV, corrosion current density 0.5, 2.5 and $6.5{\mu}A/cm^2$ respectively. The film resistance measured by EIS are Zr 63,000, Ti 39,700 and 316L $3,150{\Omega}$, and the current of Zr-Ti couple is $0.03{\mu}A$, whereas Zr-316L SS is $0.1{\mu}A$. According to the result of this experiment in 3.5% NaCl solution, Zr is excellent corrosion resistance material than Ti and STS 316L.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.7
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• pp.3284-3292
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• 2013

The purpose of this study was to translate QUEST 2.0 in Korean with valid translation process and to measure psychometric characteristics. Translation process was consist of six steps. Internal consistency was analyzed by Cronbach's ${\alpha}$. Test-Retest reliability was analyzed by Spearman Rank Correlation Coefficient. Internal consistency of 'Assistive device' was .88, 'Services' .92. There was no statistically significant difference according to repetitive measure. The spearman correlation coefficient was .64 for "Assistive Device" and .66 for "Services". This result reflects K-QUEST 2.0's (Korean-Quebec User Evaluation of Satisfaction Assistive Technology 2.0) safety, consistency, and predictability in aspect of measure. In this study, the K-QUEST 2.0 was translated into Korean and the reliability of K-QUEST 2.0 was tested. Decisively, the K-QUEST 2.0 can be applied to evaluate user satisfaction of assistive technology.

• Journal of Environmental Impact Assessment
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• v.6 no.2
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• pp.35-59
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• 1997

In this study, for the effective environmental investigation at the level of planning, environmental assessment model to be integrated with urban comprehensive plans was developed. This model was applied to the Suwon City urban comprehensive plan and was tested to derive the future application program and the adaptability to the current research issues. The results of this study can be summarized as follows: First, we defined basic items for environmental assessment as to be used in the developed SEA model. We also defined three ranges and twelve items for the environmental assessments, which can be used in the assessment of the urban comprehensive plan through the expert advices. Second, we performed the case study by applying the developed SEA model to the Suwon City urban comprehensive assessment, and investigated the environmental impacts through an expert inquiry at the "phase 5" of the model. The results of the case study showed that Suwon City urban comprehensive plan contained partially discrepancies at the goal of the planning. The spatial strategy for leisure, park and open space, and green belt was analysed not to be effective in energy use. The case study also indicated that the environments of Suwon City are expected to be much worse in each sectional plan, if the City was to implement the present five sectional plans for life boundary and distribution of population, land use plan, transportation plan, industrial development plan, and life environmental plan. Third, according to the result of the case study, an mitigation plan for urban comprehensive plan of Suwon City was proposed as the following four stages; modification of planning goal, modification of site alternatives, modification of planning contents, and proposal of mitigation measures.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.4
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• pp.381-389
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• 2005

To Analysis of Correlation of Visual Function Findings, by assessing convergence and accommodation, 92 selected objects without any ocular diseases by apperatuses of visual chart(Shinnippon CT30) and phoropter(Shinnippon VT10) at a shan distance(40 cm) were tested upon MEM retinoscopy(Welch Allyn, USA), BELL retinoscopy(Welch Allyn, USA), binocular accommodative facility (${\pm}2.00$ D nipper, Bernell Co., USA), vergence facility(prism nipper, Bernell Co., USA). The results showed as follows. MEM retinoscopy(accommodative lag) showed the same result of a right eye and left eye. Bell retinoscopy(accommodative lag) showed higher correlations between right and left eye than MEM. The lower accommodative lag meant the higher accommodative facility. The binocular accommodative facility(polaroid) was higher than binocular accommodative facility(red-green). Correlations of accommodative facility between right and left eye were higher, and as the higher monocular accommodative facility also meant the higher binocular accommodative facility, monocular and binocular accommodative facilities were relative to vergence facility, These findings can be used as a clinical guide by curing patients' visual function.

• Journal of Environmental Science International
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• v.23 no.2
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• pp.207-218
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• 2014

A ventilation model was developed for predicting the air change per hour(ACH) in buildings and the airflow rates between zones of a multi-room building. In this model, the important parameters used in the calculation of airflow are wind velocity, wind direction, terrain effect, shielding effect by surrounding buildings, the effect of the window type and insect screening, etc. Also, the resulting set of mass balance equations required for the process of calculation of airflow rates are solved using a Conte-De Boor method. When this model was applied to the building which had been tested by Chandra et al.(1983), the comparison of predicted results by this study with measured results by Chandra et al. indicated that their variations were within -10%~+12%. Also, this model was applied to a building with five zones. As a result, when the wind velocity and direction did not change, terrain characteristics influenced the largest and window types influenced the least on building ventilation among terrain characteristics, local shieldings, and window types. Except for easterly and westerly winds, the ACH increased depending on wind velocity. The wind direction had influence on the airflow rates and directions through openings in building. Thus, this model can be available for predicting the airflow rates within buildings, and the results of this study can be useful for the quantification of airflow that is essential to the research of indoor air quality(temperature, humidity, or contaminant concentration) as well as to the design of building with high energy efficiency.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.1
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• pp.1-7
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• 2014

Nanofluids, suspending nano-particles of various materials, have a good heat transfer characteristics compared with pure base fluids. For the reason, nanofluids have been considered as one of the measure to improve energy efficiency, and studied to apply on a working fluid of a high performance heat exchanger. This study tested thermal conductivities of nanofluids applying diamond nano-powder on DI water, ethylene glycol, and ethyl alcohol. Nanofluids are fabricated by matrix synthetic method, and the volume percent of diamond nano-powder contained in the base fluid are 0.1, 0.3, 0.5, and 1vol%. As a result, thermal conductivities are enhanced with applying diamond nano-power. Especially, the conductivity is highly increased up to 23% at 1vol% nanofluid applying diamond nano-powder on DI water.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.1
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• pp.15-22
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• 2014

Multiple devices have been installed to reduce exhaust emissions and to increase thermal efficiency. Those devices reduce the exhaust pipe opening area and increase the exhaust gas pressure. The pressure increase disturbs a gas flow and has a bad effect on the engine performance. However there is some study that NOx can be reduced with exhaust gas pressure increase. In this study an engine performance is tested with various opening ratios. The result shows that the fuel consumption rate is reduced in case of little amount of the pressure increase, and NOx is reduced with the pressure increase, while the concentration of the toxic exhaust gases are increased in the case of high back-pressure.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.1
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• pp.207-214
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• 2014

Recently, smartphone spyware resembles various types of virus components in PCs and has trends getting more and more severe. Users do not perceive the risk factors severely even if smartphone security is very vulnerable in spite of the smartphone spyware growth. Thus, this study observes the influence of information security in selecting smartphone based on the personal inclinations and spyware perceptions. The main variables of study model are such as the degree of personal risk-accepting and the risk of smartphone spyware as independent variables and smartphone purchasing intention as a dependent variable. The model is tested using SPSS 21 packages on the effective 200 samples gathered through questionnaire survey on the present smartphone users. As a result, the two main hypotheses which are "the degree of personal risk-accepting will influence on the perceiving risk of smartphone spyware" and "the perceiving risk of smartphone spyware will influence on smartphone purchasing intention" were significant statistically. Therefore, we could find out information security's influence on the selecting smartphone.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.1850-1858
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• 2014

The object of this study is to develop an cooling control algorithm for electronics devices of the electric vehicle. In order to estimate the existing cooling control logic of the electronic devices for the small and medium sized electric vehicle, the experiments on the coolant temperature variation of the cooling system were conducted under 4 different seasons conditions. As a result, the existing cooling control logic were overcooled when it was compared with the reference temperature for a required cooling load. In addition, the newly developed optimum cooling control logic for improving the mileages of the tested electric vehicle with consideration of the ambient temperature, vehicle speed, and refrigerant temperature of the air conditioning on/off is necessary.