• Proceedings of the KSME Conference
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• 2003.04a
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• pp.513-518
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• 2003

The piston slap phenomenon is one of the major noise source of reciprocating compressors used in household electric appliances. In response to public demand, strict regulations are increasingly being imposed on the allowable noise level which is caused mostly by household electric appliances. In this paper, the dynamic behavior of suction and discharge valves are analytically calculated and the lubricant behavior between piston and cylinder are investigated using two-dimensional Reynolds equation. And the piston slap caused by the piston secondary motion is investigated by the finite element method.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.733-736
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• 2002

The inside configuration of intake nozzle of vacuum cleaner greatly affects the dust-collection efficiency and acoustic-noise effect generated from flow separation Interaction between high-speed flow and internal structure. In order to improve the performance of the vacuum cleaner, flow fields inside the intake nozzles were investigated using flow visualization and FIV (Particle Image Vetocimetry) technique. The measurement to aerodynamic power, suction efficiency and noise level were also carried out. Valuable information was obtained from the experiments, revealing how to modify the intake nozzle. In this paper, the results of visualization, velocity distribution of flow fields, aerodynamic power, suction efficiency and noise level are discussed.

• Journal of the Korean Home Economics Association
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• v.31 no.3
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• pp.113-125
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• 1993

The purpose of this paper was to investigate the relations among wife's job and family life structure of couples, and to compare them between Japan and Korea. The data for this study was obtained from a survey of 247 Japanese couples who were risiding in Osaka and 235 Korean couples in Deagu, 1992. The major findings of this study can be summarized as follow: 1. The contents of Household works is classified into three factors-daily routine houseworks, child-rearing, economic-management of household, in Korea, and into two factors-daily routine houseworks, child and economic management, in Japan. The contents of descision making is classified into four factors-husband's personal sphere, family life management, wife's personal sphere, and home economic sphere, in Korea, and three factors-husband's personal sphere, economic life management of family, and wife's personal sphere, in Japan. 2. In Korea and Japan, wife's job have not effect on couple's marital satisfaction, directly. However, wife's job contribute to husband's share of daily routine houseworks.

• KDI Journal of Economic Policy
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• v.28 no.2
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• pp.1-49
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• 2006

Considering the fact that households' demographic characteristics affect consumption decision, it is conjectured that rapid demographic changes would lead to a substantial change in the composition of private consumption expenditure. This paper estimates the demand functions of various consumption items by applying the Quadratic Almost Ideal Demand System(QUAIDS) model to Household Income and Expenditure Survey data, and then provides a long-term forecast of the composition of household consumption expenditure for 2005-2020. The paper shows that Korea's consumption expenditure will maintain the recent years' rapid change, of which a considerable portion is due to rapid demographic changes. Results of the paper can be utilized in forecasting the change in the industrial structure of the economy, as well as in firms' investment planning.

• Journal of the Korea Furniture Society
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• v.27 no.3
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• pp.237-245
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• 2016

Single households currently account for 26.5% of all households and their number is expected to continue to rise, reaching 34.5% by 2035. An analysis of the consumption trends and needs of single households shows that they are rising as a new consumer group with a focus on investment on the individual and favouring: small but high-tech products: efficient use of limited resources: safety and peace of mind: self-improvement and leisure. Products which meet such demands are having an impact on the growth of home-furnishing market. An analysis of companies in Korea's home-furnishing market, with examples like the lifestyle company IKEA, shows a variety of brands such as SPA brand, furniture specialist, distributor and character products. And yet most are OEM products which lack differentiated product lines and compete with similar display and distribution structure. We needs the Single household consumption tendency of home-furnishing market and differentiation strategy through product analysis. In order to increase the value of companies in the home-furnishing market, in addition to differentiated design, product competitiveness must aspire to higher customer satisfaction with easy assembly, innovation in logistics, innovative sales methods such as virtual-reality simulation for products and space, individually-tailored furniture for the needs of single household and products which combine smart technology. For home-grown home-furnishing brands to have competitiveness, they must leverage on the strengths of the industry, offering differentiated and competitive products in a wider range of areas with convergence functions as well as differentiation in consumer interface and application of advancing technology; in-depth product research is called for.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.45 no.2
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• pp.139-150
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• 2019

This study is investigated sunscreen formulation that enhances UV absorption efficiency by UV light. Ethylhexyl methoxycinnamate (OMC) is one of the most common UV filters. Many studies have been conducted about photostability of OMC. It is well known that under the UV exposure, trans-OMC could turn to cis-OMC, or produce various photoproducts including its dimers. Those chemical structure changes were understood as the reason of a decrease in UV absorption efficiency upon UV exposure. However, it was found that OMC and isoamyl p-methoxycinnamate (IMC) could even enhance its UV absorption efficiency when it was exposed to UV light in an environment similar to actual use. In order to develop sunscreen formulation that enhances UV absorption efficiency by UV light, emollient with high polarity and compatibility should be avoided from the formular. Those emollient seemed to prevent OMC or IMC from producing photoproducts under UV light. Finally, a sunscreen formulation (UV sensing SPF boosting formular) enhancing UV absorption efficiency by UV was developed by the UV activated SPF boosting technology, and the effect of the sunscreen was evaluated. in vitro SPF of the sunscreen was increased from 50.69 to 72.33 when it was exposed to UV light and its in vivo SPF (53.7) was 56.10% higher than that of the control sunscreen (below 34.4).

• The Korean Journal of Applied Statistics
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• v.35 no.4
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• pp.553-568
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• 2022

The Household Income and Expenditure Survey is a representative survey of Statistics Korea, which aims to measure and analyze national income and consumption levels and their changes by understanding the current state of household balances. Recently, the disconnection problem in these time series caused by the large-scale reorganization of the survey methods in 2017 and 2019 has become an issue. In this study, we model the characteristics of the time series in the Household Income and Expenditure Survey up to 2016, and use the modeling to compute forecasts for linking the expenditures in 2017 and 2018. In order to evenly reflect the characteristics across all expenditure item series and to reduce the impact of a specific forecast model, we synthesize a total of 8 models such as regression models, time series models, and machine learning techniques. In particular, the noteworthy aspect of this study is that it improves the forecast by using the optimal combination technique that can exactly reflect the hierarchical structure of the Household Income and Expenditure Survey without loss of information as in the top-down or bottom-up methods. As a result of applying the proposed method to forecast expenditure series from 2017 to 2019, it contributed to the recovery of time series linkage and improved the forecast. In addition, it was confirmed that the hierarchical time series forecasts by the optimal combination method make linkage results closer to the actual survey series.

• Korean Journal of Rural Living Science
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• v.7 no.1
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• pp.81-97
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• 1996

The purpose of this study was to analyze the structure of time use by housewives in rural households, and to compare the time use structure of housewives with that of their husbands. To attain this goals, we have selected 108 farmhouses considering agricultural area and size in L993. Data was collected by observing how (i. e., doing what kinds of work) housewives and husbands spend time, Time use was divided into four categories : physiological time, socio-cultural time, household work time and agricultural labor time. The results in this study present a valuable insight to assuage the overloaded works of rural housewives. The major results can be outlined as follows : 1. Rural housewives worked 1.2 times longer hours a day than their husbands did. 2, There existed a severe labour time imbalance between housewives and husbands during the busy farming season. 3. The time use patterns of housewives and husbands were significantly different across agricultural areas. Also, the education level of a housewife was associated with the length of her labor time.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.2
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• pp.184-189
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• 2013

Compared to a multiphase SRM, a single-phase SRM has some advantages, such as lower number of switches and power converter size, which leads to gradually increasing in the household appliances and industrial applications. But the torque dead zone is existed in the single-phase SRM which decreases the starting capability of the motor and increases the torque ripple. In order to solve the aforementioned problems, a single-phase hybrid SRM with commercial ferrite permanent magnet is proposed in this paper. Basic design principle for the proposed structure is described. To verify the proposed structure, FEM is employed to get the characteristics of the proposed structure. Based on the analysis, a prototype is designed and manufactured. And, the experimental system is also constructed. The validity of the proposed structure is verified by the experimental results.

• Korean Journal of Human Ecology
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• v.7 no.1
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• pp.131-143
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• 2004

The purpose of this study was to examine the consumption expenditure structure for leisure & recreational service in urban households. For these purpose, the data collected 175 households in Pusan metropolitan city. Statistics employed for the analys were frequencies, means, one -way ANDVA, and multiple regression analysis. The major results of this study were as follows; Average monthly expenditure for leisure, recreational service was 190,342 won. And their expenditure for leisure & recreational service share was 12.89 % of total expenditure. Those expenditure with high income elasticity were hobby & culture education, and journey. And those with low income elasticity were play & inspection, and health & sports. In leisure & recreational service expenditure, the variables which influence were job and degree of household head, and income.