• Journal of Korean Society of Transportation
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• v.26 no.2
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• pp.69-78
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• 2008

Tour traffic takes largely place at certain limited period of time so that it is desirable to adopt some kind of software-typed approaches like the introduction of a new traffic system rather than hardware-typed ones of extension or construction of roads, and which naturally leads to the need of establishing a new tour traffic policy that makes the most profit at the lowest cost. In this research, I studied cognitive characteristics of traffic congestion of tour traffic and non-tour traffic and constructed a transfer traffic-choice behavior model for the introduction of transfer-traffic system and examined its influence factors. As a result, it is revealed that respondents feel much more the cognitive strength of traffic congestion at tourist resorts than they feel usually at non-tourist sites. That means the necessity of the introduction of the policy that enhances access to tourist resorts. In closing, through the transfer-traffic choice behavior model, I identified the fact that the introduction of transfer-traffic system could convert the trend of highly frequent use of passenger cars on tourism season into public transportation use, which shows that relevant policy-makers ultimately need to make a comprehensive policy considering traffic aspect in revitalizing tour resorts.

• Journal of The Korean Association For Science Education
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• v.40 no.1
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• pp.77-87
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• 2020

Scientific inquiry has emphasized its importance in various aspects of science learning and has been performed according to various methods and purposes. Among the various aspects of science learning, it is emphasized to develop core competencies with science, such as scientific thinking. Therefore, it is necessary to support students to be able to formulate scientific reasoning properly. This study attempts to explore problem-finding and scientific reasoning in the process of performing scientific inquiry. This study also aims to reveal what factors influence this complex process. For this purpose, this study analyzed the inquiry process and results performed by two groups of college students who conducted the inquiry related to osmosis. To analyze, research plans, presentations, and group interviews were used. As a result, it was found that participants used various scientific reasoning, such as deductive, inductive, and abductive reasoning, in the process of problem finding for their inquiry about osmosis. In the process of inquiry and reasoning complexly, anomalous data, which appear regularly, and the characteristics of experimental instruments influenced their reasoning. Various reasons were produced for the purpose of constructing the best explanation about the phenomena observed by participants themselves. Finally, based on the results of this study, several implications for the development context of programs using scientific inquiry are discussed.

• Journal of the Korean Wood Science and Technology
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• v.38 no.3
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• pp.191-198
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• 2010

This research was performed to investigate the effect of hydrogen peroxide on the stain removal in japanese hackberry. Response surface method (RSM) was used to optimize the bleaching conditions such as reaction temperature, reaction time and the concentration of hydrogen peroxide. Fifteen different bleaching conditions were selected according to $2^3$ factorial central composite design (CCD). The bleaching effect were evaluated by lightness differences of wood surface before and after the bleaching. The RSM model was determined and its $R^2$ values were 0.93, showing it well represented the bleaching effect. The most affecting factor on the stain removal was the concentration of hydrogen peroxide, followed by reaction time and reaction temperature. Second degree of concentration was proved to have an effect on the bleaching. Bleaching rates above 3% concentrations of hydrogen peroxide were tended to be slightly decreased, and low bleaching effect was found at $20^{\circ}C$. The determined RSM model may offer very practical ways to obtain the desired levels of bleaching because it offers multiple solutions.

• Applied Chemistry for Engineering
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• v.20 no.2
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• pp.234-240
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• 2009

$Mg(OH)_2$ particles were prepared by precipitation and a hydrothermal treatment to examine the effect of $MgCl_2$ concentration, alkali type and concentration, temperature, hydrothermal treatment on the formation of $Mg(OH)_2$ particles using full factorial design, as one of DOE (Design of experiment) methods. The primary particle size is similar to the secondary particle size for the samples after the hydrothermal treatment, where the average particle size of $Mg(OH)_2$ increased with increasing the concentration of $MgCl_2$ and hydrothermal temperature and decreasing alkali/Mg molar ratio. On the other hand, for the samples prepared from precipitation, the secondary particle size is larger than the primary particles due to aggregation. The difference in alkaline source is that the particles prepared from $NH_4OH$ exhibit the larger size with better dispersion than those from NaOH. Low density polyethylene and ethylene-co-vinyl acetate (LDPE-EVA) resin composed of the smaller secondary particle size of $Mg(OH)_2$ shows a higher limited oxygen index (LOI) at 50 and 55% loading, but the smaller primary particle size may result in a better grade in UL-94 tests. At the high loading of 60%, all samples with any preparation methods exhibit V-0 grade but the LOI value depends on not only primary particle size but also dispersion state.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.225-231
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• 2002

The physicochemical characteristics of pine nuts gruel were investigated to find the effects of processing condition during the processing. Three-dimensional response surface methodology was applied to investigate effects of ratio of water volume and pine nuts weight to rice weight and heating time on dependent variables of the physicochemical characteristics. The dependent variables in physicochemical characteristics were viscosity (cP), spreadability (cm), pH, soluble solid content (%), color, total sugar (%) and amylose content (%). The F-value of ratio of water volume and pine nuts weight to rice weight and heating time to viscosity were 8.91, 4.54 and 5.02 respectively and they are significantly different at 5% level. The F-value to spreadability were 5.44, 7.88 and 8.04 respectively and they are significantly different at 5% level. These results suggest that water volume, pine nuts weight and heating time greatly affect the viscosity and spreadability of pine nuts gruel. The processing condition also affect the soluble solid content. The changes of the processing condition did not affect the pH of pine nuts gruel. We found that the L, a, b value were affected more by ratio of water volume and pine nuts weight to rice weight than by heating time. The water volume affected more the total sugar and amylose content of pine nuts gruel than pine nuts weight and heating time.

• Korean Journal of Food Science and Technology
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• v.35 no.5
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• pp.777-782
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• 2003

Response surface methodology (RSM) was used to monitor the characteristics of ethanol extracts from Hericium erinaceus. A central composite design was applied to investigate the effects of independent variables, ethanol concentration $(X_1)$, and sample ratio $(X_2)$ on dependent variables, soluble solid $(Y_1)$, total phenols $(Y_2)$, crude protein $(Y_3)$, electron donating ability $(Y_4)$, and browning color $(Y_5)$ of the extracts. As the sample ratio increased, the soluble solid content increased. Ethanol concentration played a minor role. Total phenols and crude protein increased with sample ratio. Sample ratio had a greater effect than alcohol concentration in the extraction of soluble solid, total phenols, crude protein, and browning color, with an exception of electron donating ability. The optimum ranges at 2 hr extraction was $3.9{\sim}5.0\;g/l00\;mL$ in sample ratio and $36{\sim}52%$ in ethanol concentration. Predicted values at the optimized conditions were acceptable when compared to experimental values.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.11
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• pp.1123-1129
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• 2015

A pair of two-way valves typically is used in automotive washing machines, where the water flow direction is frequently reversed and highly pressurized clean water is sprayed to remove the oil and dirt remaining on machined engine and transmission blocks. Although this valve system has been widely used because of its competitive price, its application is sometimes restricted by surging effects, such as pressure ripples occurring in rapid changes in water flow caused by inaccurate valve control. As an alternative, one three-way reversing valve can replace the valve system because it provides rapid and accurate changes to the water flow direction without any precise control device. However, a cavitation effect occurs because of the complicated bottom plug shape of the valve. In this study, the cavitation index and percent of cavitation (POC) were introduced to numerically evaluate fluid flows via computational fluid dynamics (CFD) analysis. To reduce the cavitation effect generated by the bottom plug, the optimal shape design was carried out through a parametric study, in which a simple computer-aided engineering (CAE) model was applied to avoid time-consuming CFD analysis and difficulties in achieving convergence. The optimal shape design process using full factorial design of experiments (DOEs) and an artificial neural network meta-model yielded the optimal waist and tail length of the bottom plug with a POC value of less than 30%, which meets the requirement of no cavitation occurrence. The optimal waist length, tail length and POC value were found to 6.42 mm, 6.96 mm and 27%, respectively.

• Food Science and Preservation
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• v.14 no.3
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• pp.269-275
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• 2007

This paper was study to develop an extract of Elaeagnus multiflora as a beverage component, and was part of a broader research project for at the development of processed foods using extract of Elaeagnus multiflora. Acceptable mixing properties of the beverage were significantly related to brix values, pH, total acidity, and total phenol contents. When brown rice vinegar was used as a supplement, the vinegar contributed only 1% of total acidity content, and the brix was below 5% of acceptable level. Maximal total acidity of the mixed beverage was attained which added 19.2%(v/v) of Elaeagnus multiflora extract and 7.6%(v/v) of brown rice vinegar. The mixed beverage contributed 0.88% of the total acidity content. The maximum condition of brix(11.5) of the mixed beverage was arrived to 24.7%(v/v) of Elaeagnus multiflora extract and 4.9%(v/v) of brown rice vinegar. The maximum polyphenol contents of beverage(14.47 mg%) was achieved which added 25.0%(v/v) of Elaeagnus multiflora extract and 4.3%(v/v) of brown rice vinegar.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.57-62
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• 2006

Busan New Port, under construction aiming for the hub of Northeast Asia and Partly in operation, had damaged up to 48 billion Won due to Typhoon 'maemi' in 2003. The present criteria of domestic harbor design only describes about the critical wave height with respect to the size of vessel for harbor tranquility. The berth operation ratio which represents the annual available berthing days is depending on the efficiency of cargo handling work and this depends on the motion of the moored vessel due to the wave action and the characteristics of cargo gears. The motion of moored vessel might be related not only to the wave height but also to wave period. Furthermore, the berth operation ratio relies on external forces such as currents and winds, including the characteristics of mooring system and the specification of the moored vessel. In this study we only deal with berth operation ratio in normal sea state, considering wave and current by measured data and numerical calculation. Especially we tried to evaluate the berth operation ratio for each berth adopting the variation of dredging and reclamation plan and the change of wave environment during the process of the new port construction. For better understanding and analysis of wave transformation process, we applied the steady state spectral wave model and extended mild-slope wave model to the related site. This study summarizes comparisons of harbor responses predicted by two numerical predictions obtained at Busan New port site. Field and numerical model analysis was conducted for the original port plan and the final corrected plan.

• Journal of the Korea Society of Computer and Information
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• v.29 no.3
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• pp.67-74
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• 2024

In this paper, we present a study aimed at analyzing how different rainfall measurement methods affect the performance of reservoir water level predictions. This work is particularly timely given the increasing emphasis on climate change and the sustainable management of water resources. To this end, we have employed rainfall data from ASOS, AWS, and Thiessen Network-based measures provided by the KMA Weather Data Service to train our neural network models for reservoir yield predictions. Our analysis, which encompasses 34 reservoirs in Jeollabuk-do Province, examines how each method contributes to enhancing prediction accuracy. The results reveal that models using rainfall data based on the Thiessen Network's area rainfall ratio yield the highest accuracy. This can be attributed to the method's accounting for precise distances between observation stations, offering a more accurate reflection of the actual rainfall across different regions. These findings underscore the importance of precise regional rainfall data in predicting reservoir yields. Additionally, the paper underscores the significance of meticulous rainfall measurement and data analysis, and discusses the prediction model's potential applications in agriculture, urban planning, and flood management.