• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.4
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• pp.871-876
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• 2011

In this paper, a voltage-controlled frequency tunable current-mode integrator and a 3rd-order current-mode Chebyshev filter in 1.8V-$0.18{\mu}m$ CMOS is realized for software radio applications in system-on-chips. This filter is used for reconstruction purposes between a current-steering DAC and a current-mode mixer. Power consumption of the designed filter can be reduced by using a current-mode small size integrator. And also, cutoff frequency of this filter is variable between 1.2MHz and 10.1MHz, the power consumption is 2.85mW. And the voltage bias compensated circuit is used to control the voltage variation.in the designed filter.

• Proceedings of the KSR Conference
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• 2009.05b
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• pp.585-592
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• 2009

The performance of screw compressor depends on lots of design parameters of rotor profile, such as length of seal line, wrap angle, blow hole, suction and discharge port size, number of rotor lobe, etc. The optimum rotor profile makes it possible to increase the compression efficiency with low energy consumption, and to minimize the loss of power. In this research, a new rotor profile design and performance analysis are done by computer simulation. It is expected that the volumetric efficiency is improved because the internal leakage is reduced due to the minimization of blow hole and clearance, and the stiffness of rotors is increased due to the reduction of length to diameter ratio. Also, the specific power consumption will be secured for use ranging from low to high operation speed.

• Journal of the Korean Society of Clothing and Textiles
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• v.43 no.3
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• pp.327-348
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• 2019

Among the many methods to make sustainable garments, convertible garments have the potential to change style and function that allow consumers to keep and use garments longer with the possibility of enhancing sustainability. This research analyzes consumer preferences in changeable design options for convertible dresses and the consumers' influence on environmentally responsible apparel consumption (ERC) behaviors on their preferences regarding changeable design options of dresses, which are popular items. An online survey collected data from a convenient sample of 321 female college students from four universities in the United States. Data were analyzed using IBM SPSS through descriptive analysis, cluster analysis, and independent samples t-test. There were significant differences between high and low ERC groups in design preferences that considered important aspects of purchasing, using convertible dresses, and purchase intentions. Detailed differences among sub-groups were analyzed. Designers are encouraged to make tying/folding/wrapping dresses with changes of size/fit, dress length, or color/pattern. The results are beneficial for apparel designers when developing convertible dresses with the guidance of consumers' design preferences and differences according to ERC levels.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.732-733
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• 2015

Currently, since the total energy amount has been increased continuously, the effort for energy efficiency of apartment building is necessary. Although the previous studies have been focused on the issue. Almost studies are about the simulation by applying the energy analysis tools and a lack of studies have been conducted the data analysis about real city gas amount of apartment building. Therefore, the objective of this study is to analyze the city gas consumption difference according to the exclusive dwelling in apartment building. To address this issue, the descriptive, correlation, analysis of variance (ANOVA) statistics are used in this study. As a result, in the case of annual total amount, the city gas is increased as the size of the exclusive dwelling area is increased. In the future, the findings of this study can be used as a basic material to develop the prediction model of city gas in apartment building.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.11
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• pp.827-834
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• 2013

The water footprint of product and service is the total volume of freshwater consumed, directly and indirectly, in the life cycle of a product and service. Up to date, water consumption data for industries and products were not well quantified and developed. Especially it is important to construct for agriculture industry which consumes lots of water. In this study, by using Cropwat 8.0 model, we tried to evaluate regionalized water consumption related with rice production in agriculture industry in eight regions (Gangwon, Gyeongi, Gyeongbuk, Gyeongnam, Jeonnam, Jeonbuk, Chungnam, Chungbuk). As a result, Gyeongbuk region has the lowest water consumption in rice production, which is $1,356.68m^3/ton$, on the other hand, Jeonnam region has the highest water consumption ($1,669.54m^3/ton$). By using the average indirect water consumption ($1,487.87m^3/ton$) of eight regions and direct water consumption, the total water footprint for the rice amount of rice bowl size (130 g), which is 193.6 L was calculated. Based on this research approach, we should develop water footprint database of all agriculture products and expand to other industrial sectors.

• Journal of Korean Society for Quality Management
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• v.50 no.2
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• pp.287-304
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• 2022

Purpose: The size of the salad consumption market has expanded since Covid-19, and continuous growth is predicted. Therefore, by extracting influential core purchasers in the salad consumption market and analyzing their purchasing behaviors and consumer types, this study intended to provide basic data for establishing a marketing strategy. Methods: The analysis data is the purchasing data of 576 people who have purchased salads between 2016 and 2020 (panel data of the Rural Development Administration), and in the social network analysis, the centrality structure was analyzed. Results: First, in the results of analyzing the causes of the rapid increase in salad consumption in 2020, it was found that the increase in consumption of new purchasers (n=102) had little effect. The existing consumer type (n = 474), which has been the majority of the salad consumption market so far, were consumers with stable income. However, the results of study indicated that the type of consumers has expanded since low-income class as well as high-income class increased consumption of purchasing salad. Second, in the results of analyzing the types of key purchasers with great influence in the salad consumption market, there was a difference from the results of frequency analysis in age, number of family members, existence/absence of children, and income decile. This suggests that there should be a difference between the type of customers according to the apparent quantitative figure and the actual influential purchasers. Third, in the results of analyzing the salad purchasing behaviors of core purchasers, the purchasing site for existing purchasers was large-scale marts and for new purchasers it was corporate-type supermarkets. Purchases were concentrated on Saturdays for both existing and new purchasers. As for the purchased products, existing purchasers had a high preference for products made of chicken, and new purchasers had a high preference for vegetable/fruit salad. In particular, in the results of purchased products by age group, in the case of 50s and 60s, it was an interesting result that there was a difference between the products purchased by the existing and new purchasers even though they were the same age. Conclusion: When establishing a marketing strategy in the salad consumption market, it is necessary to pay attention to the purchasing behavior of key buyers.

• Journal of the Korean Institute of Gas
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• v.8 no.2 s.23
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• pp.15-27
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• 2004

The purpose of this paper is to improve the performance of Polymer electrolyte fuel cell(PEMFC) by studying the channel dimension of bipolar plates using commercial CFD program 'Fluent'. Simulations are done ranging from 0.5 to 3.0mm for different size in order to find the channel size which shoves the highst hydrogen consumption. The results showed that the smaller channel width, land width, channel depth, the higher hydrogen consumption in anode. When channel width is increased, the pressure drop in channel is decreased because total channel length Is decreased, and when land width is increased, the net hydrogen consumption is decreased because hydrogen is diffused under the land width. It is also found that the influence of hydrogen consumption is larger at different channel width than it at different land width. The change of hydrogen consumption with different channel depth isn't as large as it with different channel width, but channel depth has to be small as can as it does because it has influence on the volume of bipolar plates. however the hydrogen utilization among the channel sizes more than 1.0mm which can be machined in reality is the most at channel width 1.0, land width 1.0, channel depth 0.5mm and considered as optimum channel size. The fuel cell combined with 2cm${\times}$2cm diagonal or serpentine type flow field and MEA(Membrane Electrode Assembly) is tested using 100W PEMFC test station to confirm that the channel size studied in simulation. The results showed that diagonal and serpentine flow field have similarly high OCV and current density of diagonal (low field is higher($2-40mA/m^2$) than that of serpentine flow field under 0.6 voltage, but the current density of serpentine type has higher performance($5-10mA/m^2$) than that of diagonal flow field under 0.7-0.8 voltage.

• Journal of the Korean Society of Clothing and Textiles
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• v.42 no.4
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• pp.657-670
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• 2018

This study investigated the wearing of jackets by down-aging middle-aged women in their 40s to 50s who enjoy wearing attire from ladies' apparel brands that target the 20s to 30s age group. As a method of research, a survey was done on middle-aged women in their 40s and 50s as the target age group. Based on the survey results, comparison and analysis was done on the wearing of jackets as well as preferred extra space and fitness of the clothes, with the distinction between the down-aging group and the non down-aging group. The down-aging middle-aged women purchased jackets mainly at department stores, outlets, discount outlets, and internet shopping malls, and showed the highest frequency of wearing the jackets once or twice a week. For the item "importance in selecting a jacket", both groups chose "the design" as the most important aspect; however, the non down-aging group took "size and fitness" and "activity and comfort" more than the down-aging group. Especially regarding the size of the jackets, size S (55) was the most often worn by the down-aging group, whereas size M (66) was the most often worn by the non down-aging group.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.6 no.2
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• pp.126-137
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• 2007

In this paper, a new method to reduce the size of ROM in the direct digital frequency synthesizer(DDFS) is proposed. And we design the phase-to-sine converter using the phase accumulator of parallel type for generating the high frequency. The new ROM compression method can reduce the ROM size by using the two ROM. The quantized value of sine is saved by the quantized-ROM(Q-ROM) and the differential ROM(D-ROM). So the total size of the ROM in the proposed DDFS is significantly reduced compared to the original ROM. The ROM compression ratio of 67.5% is achieved by this method. Also, the power consumption is decreased according to the ROM size reduction.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.30 no.4
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• pp.28-34
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• 1998

Polyvinyl acetate emulsion has been widely used as adhesives for wood and paper, paint additives and binders for fiber, leather, and other materials because it is an excellent adhesive with many advantages including low in toxicity risks and manufacturing cost. It is expected the consumption of polyvinyl acetate emulsion as adhesives will increase in cigarette industry as well as in paperboard coating industry. Recently the operation speed of the cigarette tip wrapper increased so substantially that improvement of the emulsion properties is required including good wet tack development, narrow and controlled particle size distribution, low viscosity, etc. In this study the effects of such polymerization conditions as the type and amount of emulsifier, internal or external plasticizing, and emulsification methods on the viscosity and particle size of polyvinyl acetate emulsions were examined. Results showed that polyvinyl alcohol with a high degree of hydrolysis and low molecular weight and nonionic surfactants are superior to anionic surfactant in improving adhesion and emulsion stability. They also tend to produce emulsions with smaller particle size. External plasticization with dipropylene glycol dibenzoate was more effective in improving flexibility than internal plasticization with butyl acrylate. Monomer emulsification under high shear was more effective in decreasing the particle size.