• Journal of Korea Water Resources Association
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• v.46 no.10
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• pp.977-987
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• 2013

This study aims to develop a multiple criteria decision making (MCDM) approach for flood vulnerability assessment which considers uncertainty. The flood vulnerability assessment procedure consists of three steps: (1) use the Delphi process to determine the criteria and their corresponding weights-the adopted criteria represent the social, economic, and environmental circumstances related to floods, (2) construct a fuzzy data matrix for the flood vulnerability criteria using fuzzification and standardization, and (3) set priorities based on the number of assessed vulnerabilities. This study uses a modified fuzzy TOPSIS method based on ${\alpha}$-level sets which considers various uncertainties related to weight derivation and crisp data aggregation. Further, Spearman's rank correlation analysis is used to compare the rankings obtained using the proposed method with those obtained using fuzzy TOPSIS with fuzzy data, TOPSIS, and WSM methods with crisp data. The fuzzy TOPSIS method based on ${\alpha}$-cut level sets is found to have a higher correlation rate than the other methods, and thus, it can reduce the difference of the rankings which uses crisp and fuzzy data. Thus, the proposed flood vulnerability assessment method can effectively support flood management policies.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.3
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• pp.317-324
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• 2020

Plastic wastes generated from domestic waste are separated by mixed discharge with foreign substances, and the cost of the separation and screening process increases, so recycling is relatively low. In this study, as a fundamental study for recycling mixed plastic wastes generated from domestic waste into concrete aggregates, changes in concrete properties according to the plastic waste types and the substitution rate were evaluated experimentally. The mixed plastic waste aggregate(MPWA) was found to have a lower density and a higher absorption rate compared to the coarse aggregate with good particle size distribution. On the other hand, the single plastic waste aggregate(SPWA) was composed of particles of uniform size, and both the density and the absorption rate were lower than that of the fin e aggregate. It was found that the MPWA substitution concrete did not cause a material separation phenomenon due to a relatively good particle size distribution even with the largest amount of plastic waste substitution, and the amount of air flow increased little. The compressive strength and flexural strength of the PWA substitution concrete decreased as the amount of substitution of the PWA increased due to the low strength of the PWA, the suppression of the cement hydration reaction due to hydrophobicity, and the low adhesion between the PWA and the cement paste. It was found that the degree of deterioration in compressive strength and flexural strength of concrete substituted with MPWA having good particle size distribution was relatively small.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.11
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• pp.1612-1617
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• 2009

Aspergillus sp. 101 was isolated from the Korean traditional soybean paste for the production of a salt-tolerant protease. The optimal condition for the production of a salt-tolerant protease was determined with various energy sources such as carbon, nitrogen, and protein, and at different culture conditions such as temperature, pH, incubation time and NaCl concentration. The most favorable organic nitrogen sources were 2% defatted soybean flour (DSF) and soy protein isolate (SPI). Optimal pH and temperature were pH 6.0 and $25{\sim}27^{\circ}C$, respectively. Therefore, Aspergillus sp. 101 protease was a mild acid (or neutral) protease. Protease production was the highest at 0.1% concentration of $CaCO_3,\;K_2HPO_4$ and Arabicgum. Aspergillus sp. 101 could grow in culture medium at 15% NaCl concentration and produce a salt-tolerant protease even at 7% NaCl. The cell mass and protease activity of Aspergillus sp. 101 cultured in a modified medium was comparatively higher in Czapek dox and protease producing media. Hence, Aspergillus sp. 101 protease can be utilized in soy or fish sauce industry as a salt-tolerant protease starter.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.6
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• pp.1129-1136
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• 2001

This study was to investigate the suitability of six domestic wheat cultivars for the Korean-style steamed bread made under optimal conditions. Six wheat flours milled from cultivars of Greu, Kumgang, Eunpa, Taptong Kobun, and Allgreu contained 13.8, 13.7, 13.7, 13.0, 11.7, 11.0% of protein. Control bread was made from blend (protein 10.5%) of 50% high strength and 50% low strength wheat flours milled from imported wheats. The volume of steamed bread made from Kumgang was highest followed by Eunpa, Tapdong, Kobun, Greu, control bread, Allgreu. Especially, the bread qualities of Kumgand and Kobun were superior to the control bread, showing better surface characteristics such as smoothness, glossiness, and whiteness, better shapes and desirable texture. Domestic wheat flours, having medium strength with high protein content above 13.0% were suitable for steamed bread except for Greu. Volumes of steamed bread made from domestic wheat flours were correlated with protein and ash content, flour color (L value), farinograph dough development time and stability, whereas spread ratio, total bread score and overall acceptability were correlated with farinograph dough stability It is concluded that flour quality is more important factor than protein content when domestic wheat flours are chosen for Korean-style steamed bread

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.10
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• pp.1484-1490
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• 2006

This study was carried out to prepare spaghetti sauce with adductor muscle of pearl oyster (SSAM) and to compare with commercial spaghetti sauce (CSS). From the results of organic acid, pH, hunter color value and sensory evaluation, the optimal addition ratio of adductor muscle of pearl oyster was 11% based for preparing SSAM and reasonable $F_0$ value was about 4 min for keeping storage of SSAM. The proximate composition of SSAM was 69.8% for moisture, 3.7% for protein, 4.2% for crude lipid and 3.4% for crude ash. SSAM was superior in sensory flavor and texture to CSS. There was, however, no significant difference (p<0.05) in sensory color between CSS and SSAM. The total amino acid content (3,033.4 mg/100 g) of SSAM was higher than that (2,305.7 mg/100 g) of CSS and the major amino acids were aspartic acid, glutamic acid, leucine and lysine. Calcium and phosphorus contents in SSAM were 48.5 mg/100 g and 27.1 mg/100 g, respectively. Calcium level based on phosphorous was 1.78, which was a good ratio for absorbing calcium. The free amino acid content and taste value of SSAM were 989.4 mg/100 g and 141.04 mg/100 g, respectively These results suggested that the major taste active compounds among free amino acid were glutamic acid and aspartic acid.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.559-562
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• 2017

In city, tracing of power transmission lines is difficult due to compound installation of overhead and underground lines, transposition, bad view caused by trees or big buildings. It is hard problem for electrical technician on site to trace power transformers or power lines to serve customers in 3 phase -4 wires power distribution systems. It is necessary that the correct and fast tracing method is required for load balancing among distribution lines. Old technology use to trace off-lines with high power impulse injection. Our proposed method use to trace live lines with very small power high frequency signal injection. Typical power transformers in the distribution system prevent propagating the higher frequency carrier signal. The proposed method uses the limited propagation ability to identify the power transformer to serve customers. Two end communication terminals are required to be synchronized between them for determination on electrically same phases. Challenging issue is to achieve synchronization without GPS providing synchronizing time. A novel power transformer and wire identification system is designed and implemented. The system consists of a transmitter and a receiver with power-line communication module. Some experiments are conducted to verify the theoretical concepts in a big commercial building. Also some simulations are done to help and understand the concepts by using MATLAB Simulink simulator.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.505-508
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• 2016

In city, tracing of power transmission lines is difficult due to compound installation of overhead and underground lines, transposition, bad view caused by trees or big buildings. It is hard problem for electrical technician on site to trace power transformers or power lines to serve customers in 3 phase -4 wires power distribution systems. It is necessary that the correct and fast tracing method is required for load balancing among distribution lines. Old technology use to trace lines with high power impulse injection. Our proposed method uses to trace lines with very small power high frequency signal injection. Simulation models for 3-phase power transformers, 3-phase wire lines, and customer loads are described to investigate the transmission characteristics of high frequency power line carrier. Distribution lines have only a limited ability to carry higher frequencies. Typically power transformers in the distribution system prevent propagating the higher frequency carrier signal. The proposed method uses the limited propagation ability to identify the power transformer to serve customers. The system consists of a transmitter and a receiver with power-line communication module. Some experiments are conducted to verify the theoretical concepts in a big commercial building. Also some simulations are done to help and understand the concepts by using MATLAB Simulink simulator.

• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.356-362
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• 2018

Hot pepper is a kind of seasoning vegetables, which is a major item in the Korean vegetable market. Since the use of hot pepper is processed into pepper powder, which is a powder form of dried hot pepper, improvement of quality and productivity of dried hot pepper is important. Therefore, this experiment was conducted to suggest proper drying method by comparing the changes of hot pepper powder ingredients considering production cost according to the drying method. As a drying method, we used sun drying and heat drying which are widely used in practice. We also compared the productivity and quality of dried hot pepper by applying a dehumidifying drying method using a dehumidifier. Drying rate of hot pepper was highest of 85.1% at heat drying. Accordingly moisture content of hot pepper powder was lowest of 13.5% at heat drying. The American Spice Trade Association (ASTA) color value, which influenced the coloring of red pepper, showed higher in heat drying and dehumidified drying treatment than the sun drying treatment. The content of capsaicinoids was higher at sun drying treatment than that of at both heat drying and dehumidified drying treatments. The content of sugar was higher at heat drying and dehumidified drying treatment where drying time was relatively short than that of sun drying treatment. Also, there was no significant difference in sugar content between the two treatments. The production cost of dried hot pepper with dehumidified drying was 9.9% more efficient than heat drying. Through this study, it was found that heat and dehumidified drying method were effective in increasing sugar content and coloring of hot pepper powder. In order to improve the capsaicinoid content of red pepper, it is considered that appropriate drying temperature and drying time should be added in the process of heat drying and dehumidified drying.

• The Korean Journal of Community Living Science
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• v.12 no.1
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• pp.69-85
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• 2001

The purpose of this study was to replace the highly imported wheat consumption with rice in order to improve the rate of food self-sufficiency. Also, the study focused on the possibility of compounded bread making with rice flour, its taste for the Korean who have westernized eating styles, and the development of rice flour compounded bread as an alternative for wheat allergic people. Therefore, the researcher produced the soaked-rice flour, toasted-rice flour, and Extrusion-Expansion of Rice (E-ER) flour by different processing methods to bake rice wheat bread with the 10～50% mixing proportion. The volume and structure of bread were observed with Scanning Electron Microscope (SEM), and the sensory quality and the baking property were analyzed with a seven-point Likert type scale of Quantitative Descriptive Analysis (QDA). The sensory quality consisted of seven qualities such as color, size and distribution of air cell, flavor, softness, chewing, and overall quality that were evaluated as higher rating showed the better quality. The results of this study are: 1. The volume of the three types of rice wheat bread was almost same or bigger than wheat bread with the 20% of mixed proportion. 2. The size and distribution of air cell of E-ER wheat bread observed by SEM were more evenly distributed that toasted-rice wheat bread. The E-ER wheat bread had soft structure and was relatively similar to wheat flour bread. However, the structure of soaked-rice wheat bread was significantly different to other types of rice wheat bread. The structure of 10% mixed all three types of rice wheat bread was similar and evenly distributed to wheat bread but was bigger and coarser as higher mixing proportion of rice flour. 3. The dark brown color of rice wheat bread showed low sensory quality. 4. Both soaking-rice flour and E-ER flour were able to be mixed with wheat flour up to the 50%, and the seven sensory quality of these wheat bread were better than those of wheat bread. Among the three types of rice flour, toasted-rice wheat bread showed low bread property and sensory quality compared to soaked-rice or E-ER wheat bread. Consequently, this study showed that rice wheat bread that contains 20～30% of rice flour was better than wheat bread in the appropriate volume, seven sensory qualities and bread property.

• 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.