• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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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.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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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.

• 대한가정학회지
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• 제31권3호
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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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• 제28권2호
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• pp.1-49
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• 2006

가구원의 연령 및 성별, 가구원 수 등 인구학적 특성이 가계의 소비구조에 영향을 미친다는 점을 고려할 때, 급격한 인구구조 변화는 우리나라 전체의 가계소비지출 구성에 지대한 영향을 미칠 것으로 짐작된다. 인구학적 특성의 변화가 소비지출에 미치는 영향을 분석하기 위하여 본 논문에서는 가계소비지출 통계자료에 Quadratic Almost Ideal Demand System(QUAIDS) 모형을 적용하여 소비지출 항목별 구성비 함수를 추정하였으며, 경제 성장률, 인구, 가구구성 등 추정에 사용된 설명변수들의 전망치를 이용하여 2005~2020년 기간 중 우리나라 가계소비지출의 구성 변화를 전망하였다. 전망 결과에 따르면, 우리나라의 가계소비지출은 향후에도 상당한 변화를 보일 것이며, 이 가운데 많은 부분은 인구학적 특성 변화에 기인하는 것으로 분석되었다. 소비구조의 변화는 산업구조의 변화를 야기한다. 따라서 자원의 효율적 배분을 위해서는 생산요소의 유연한 산업 간 이동을 촉진하기 위한 정책적 노력이 필요하다. 한편, 본 논문의 전망 결과는 기업의 투자계획 수립에 있어 유용한 정보로 사용될 수 있다.

• 한국가구학회지
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• 제27권3호
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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.

• 대한화장품학회지
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• 제45권2호
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• pp.139-150
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• 2019

자외선에 의해 자외선 차단 효율이 상승하는 선크림에 대한 연구를 수행하였다. Ethylhexyl methoxycinnamate (OMC)는 가장 널리 쓰이는 자외선 차단제이고, OMC에 대한 광안정성 연구는 오랫동안 수행되어왔다. OMC는 자외선에 의해 trans구조가 cis구조로 변하거나, dimer를 비롯한 광반응물을 생성하여 자외선 차단효율이 떨어진다고 알려져 왔다. 하지만 본 연구에서는 OMC나 isoamyl p-methoxycinnamate(IMC)와 같이 메톡시신나메이트 구조를 공유하는 자외선 차단제들이 실제 사용조건과 유사한 조건에서 자외선에 노출 시키고 잘 설계된 실험 방법으로 in vitro SPF 수치를 측정하였을 때 오히려 자외선 차단 효율이 증가하는 것을 발견하였다. 이것은 자외선에 의해서 생성된 광반응물과 OMC간의 ${\pi}-{\pi}$ stacking을 통한 ${\pi}-{\pi}^*$ 전이 에너지 변화(UV activated transition) 때문인 것으로 생각된다. 이 발견을 선크림 개발에 적용하기 위해서는 함께 사용되는 에몰리언트의 극성 및 상용성을 적절히 고려해야 한다. 상용성이 좋은 극성 에몰리언트를 포함하면 자외선에 의해 OMC가 광반응물을 생성하지 않기 때문에 발견의 효과가 감소하는 것으로 보인다. 이러한 작용 기전(UV activated SPF boosting)을 바탕으로 상업용 수준의 선크림을 제조하여 평가해보았다. 그 결과 자외선(2 MED)에 노출되었을 때 in vitro SPF 수치는 50.69에서 72.33으로 42.69%로 증가하였고 in vivo SPF 평가에서는 53.7을 얻어 같은 조건의 대조군의 선크림(SPF 34.4 이하) 대비 56.10% 이상 높게 측정되었다. 따라서 OMC와 IMC가 특정 조건에서 UV sensor처럼 작용하여, 자외선에 노출 되었을 때 자외선 차단 효율을 높일 수 있는 선크림을 제조할 수 있었다.

• 응용통계연구
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• 제35권4호
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• pp.553-568
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• 2022

가계동향조사는 가구에 대한 가계수지 실태를 파악하여 국민 소득·소비 수준과 그 변화의 측정 및 분석 등을 목적으로 하는 통계청의 대표적인 조사이다. 최근 여러 기관들에서 2017년과 2018년의 가계동향 지출부문에서 발생한 시계열 단절에 대한 문제를 인식하고, 이 기간에 대한 시계열 연계를 위한 관련 연구를 진행하고 있다. 본 연구에서는 2016년까지의 가계동향 조사 시계열 특성을 파악하고, 이를 반영하여 2017년과 2018년의 지출액에 대한 시계열을 연계하는 예측값을 도출한다. 본 연구에서는 각 지출 항목들의 시계열적 특성을 골고루 반영하는 동시에 특정 예측 모형의 영향을 줄이기 위하여 총 8개의 회귀모형, 시계열모형, 머신러닝 기법을 합성하여 사용하였다. 특히 본 연구의 주목할 만한 특징은, Top-down 또는 Bottom-up 방식이 아닌, 정보의 손실없이 가계동향조사의 계층 구조를 반영할 수 있는 optimal combination 기법을 사용하여 예측력을 향상시켰다는 점이다. 2017년부터 2019년 자료에 대한 가계동향 지출 부문의 연계 분석 결과, 본 연구가 제안하는 연계 방식이 시계열 단절성 회복 및 예측력 향상에 기여하며, 또한 optimal combination 기법에 의한 계층 조정 후의 예측값이 조사자료에 보다 근접한 결과를 보여줌을 확인하였다.

• 한국농촌생활과학회지
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• 제7권1호
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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.

• 전기학회논문지
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• 제62권2호
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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.

• 한국가정과학회지
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• 제7권1호
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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.