• 드라이브 ㆍ 컨트롤
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• 제15권4호
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• pp.39-47
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• 2018

Recently, as environmental regulations for earth-moving equipment have been tightening, advanced systems such as electronic control, have been introduced for energy savings. An IMV (Independent Metering Valve) consisting of four 2-way valves, is an electro-hydraulic control systems that provides more flexible controllability, and potential for energy savings in excavators, when compared to the conventional 4-way spool valve system. To fully maximize use of an IMV, the bi-directional flow control valve that can regulate a large amount of flow in both directions, should be adopted. The hydraulic circuit of an IMV applied to an excavator from an overseas construction equipment company, reveals the flow control valve with the compound of proportional solenoid valve for first stage, and 2-way spool valve for the second stage. Moreover, the two spools are interconnected by a feedback spring, presumed to compensate for flow force acting on the second stage spool. This paper addresses the static analysis of flow control valve in an IMV to investigate the improvement of robustness, against flow force by the feedback spring. From the steady-state analysis of flow control valve model, it can be concluded that the feedback spring facilitates maintaining linearity of spool displacement for control input, and relatively constant flow for load disturbance.

• 한국의류산업학회지
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• 제3권5호
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• pp.455-465
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• 2001

Assessing soil removal is of interest to the washing machine industry because of government-mandated energy savings and changes in detergent formulation and consumer laundry practices. We designed this study to examine the laundry process from a holistic perspective by integrating factors perceived to be of importance. Our purpose was to assess the impact of selected variables (fabric and soil type, wash temperature and time. detergent amount, and degree of agitation) on soil removal using accelerated laundry conditions. We used the Taguchi method to develop the research design and ANOVA to analyze the data. Although soil removal was affected by fabric type, soil type, type and amount of detergent, degree of agitation, wash time and temperature, and water hardness and volume, wash temperature was the most significant variable.

• International Journal of Human Ecology
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• 제9권1호
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• pp.81-95
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• 2008

This paper examined the impact of psychological characteristics of consumers on household debt decisions. With the use of the Heckit models (the traditional approach to the selection problem) this study undertook an empirical study of the influence of a wide range of factors on financial decisions. This study used U.S. household-level data that offers detailed information on household debt, expectations about future income, expectations about future economic conditions, the amount of financial risk the respondent was willing to take, and the amount of time allotted for planning family savings and spending. This study showed that respondents with both substantial financial risk tolerance and positive expectations about future income were likely to have larger household debt showing that researchers and policy-makers need to consider consumer sentiment and preference measures in modeling behavior in credit markets. Additional results showed that household debt is significantly related to two key economic variables: income and net worth.

• 조명전기설비학회논문지
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• 제28권1호
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• pp.105-113
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• 2014

Currently, the energy consumption rate in buildings is approximately 28.5% of the total energy consumption in Korea. Therefore the amount of the consumption of petroleum resourses is at a worrying level of the blackout. The system of the amount of the Architectural Energy Efficiency Grade [AEEG] is in force by the government to apply the technologies of the Emissions Trading System and the Target Management System to mitigate the Green House Gases for buildings according to the climate change. On the account the mitigation of the Green House Gases and the reduction of the energy, from the view of maintenance and management, for the new and remodeling buildings should be under consideration. The author wants to present the possible ways how to improve the AEEG for the existing buildings by trying to establish the foundation of the BEMs, and by confirming the potential of the energy savings.

• 조명전기설비학회논문지
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• 제19권6호
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• pp.1-8
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• 2005

건물 내에 존재하는 자연광은 조명원으로 국한되지 않고 시각적, 심리적 자극을 통한 실내 환경의 질적 향상에 이르기까지 에너지절약 및 공간의 쾌적성에 큰 영향을 미친다. 유입되는 자연광량에 비례적으로 연동되는 건물에너지는 전기조명에너지를 절감시키고 난방 기간동안 일사열의 유입에 따른 난방에너지를 절감시킨다. 여름철에는 전기조명의 소등으로 인한 조명원의 발열량이 감소됨으로써 냉방부하의 감소에 이르기까지 포괄적인 영향을 미친다. 조명개발분야의 선진국에서는 에너지 절약형 광원의 대체와 아울러 자연채광과 통합된 최적 조명제어 기술의 운용만이 건물이 가지고 있는 에너지 절약의 잠재력을 현실화시킬 수 있다고 판단하고 있다. 따라서 본 연구는 일반적인 사무소 모델 공간의 에너지 절약형 인공조명을 대상으로 자연광 유입에 따른 연동적 조명제어 기법을 적용하는 경우를 대상으로, 인공조명의 소등량에 따른 조명에너지의 절감량과 이에 수반되는 냉방에너지의 점감량 및 일사열 취즉에 따른 겨울철 난방 부하 절감량을 분석함으로써 자연채광의 건물에너지에 대한 연간 기여도를 통합 분석하였다. 특히 자연채광의 성능은 실험을 통한 측정 데이터를 이용하고 에너지 해석 프로그램을 재구성하여 실질적인 절감량을 도출하도록 시도하였다.

• 한국건설관리학회논문집
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• 제19권6호
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• pp.124-134
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• 2018

모듈러 주택은 많은 장점이 있음에도 불구하고, RC구조에 익숙한 소비자들의 모듈러 주택에 대한 낮은 선호도가 모듈러 주택의 높은 공사비를 초래하고 있다. 모듈러 건축물의 공사비는 RC 구조 대비 130% 전후로 형성되어 있어 모듈러 건축물의 경제성 확보가 시급하다. 따라서 본 연구에서는 모듈러 주택의 공종별 절감가능 금액을 산출한 후, 장기적 관점에서의 경제성 분석을 진행하였다. 연구 진행을 위해 모듈러 주택의 내역서를 공장제작분 및 현장설치분으로 분개하여 공종별 발생하는 재료비, 노무비, 경비를 비교 분석을 진행했다. 그 후 파레토도를 작성하여 비용 누계 80% 내외에 포함되는 핵심 공종을 찾아 공사비 절감 가능대상으로 선정하였다. 국내 모듈러 건축의 시장규모가 일본, 유럽 국가 등 모듈러 선진국 수준과 비슷하다는 가정하에 전문가 인터뷰를 통해 모듈러 공법의 특성을 반영한 비용절감 방법을 설정하였고, 모듈러 업체 전문가를 대상으로 한 설문조사를 통해 비용절감 방법을 적용했을 때의 공종별 절감 가능 금액을 산출하고, 총 절감가능 금액을 산출했다. 비용절감 방법 중 '자동화 및 기계화'방법을 적용했을 때의 절감가능성이 1.54%로 가장 큰 것을 알 수 있었고, 국내 모듈러 생산 과정이 전자동화 및 기계화가 된다면 공사비 절감 뿐만 아니라 공기 단축도 기대해 볼 수 있다고 판단한다.

• 한국기후변화학회지
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• 제1권3호
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• pp.205-210
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• 2010

LED 조명이 기존 조명 대비 80% 이상의 에너지 절감 효과 및 환경 친화적 특성 등 다양한 장점을 가지고 있으면서도, 높은 가격으로 인해 시장이 제대로 형성되지 못하고 있다. 이에 본 논문은 공공부문의 기존 백열 전구를 LED 조명으로의 교체로 인한 에너지 절감 및 유지 보수 측면에서의 효율성을 분석하기 위해 LED 조명에 대한 경제성 평가를 통해 보급 확대에 대한 타당성을 논하였다. 분석대상은 에너지관리공단에서 시행한 "퇴출관리시스템"을 바탕으로 지식경제부에서 발표한 '백열 전구 현황 및 퇴출실적'을 이용하였다. 공공기관의 백열 전구의 LED 조명 교체에 대한 타당성 분석을 위해서 교체 비용, 연간 절전량 및 전기요금 절감액, 유지보수 비용, $CO_2$ 저감량, 탄소배출권 판매수익을 고려하였다. 경제성 분석 결과, 기존의 백열 전구를 LED 조명으로 교체 시 할인율이 3.26%일 때, 8,648.4백만원으로 NPV가 '양(+)'의 값을 가지는 것으로 분석되어 수익성이 있는 것으로 나타났다.

• 가족자원경영과 정책
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• 제16권4호
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• pp.131-152
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• 2012

The aims of this study were to analyze middle-aged households' financial preparation for retirement. Specifically, this study surveyed the relation between human capital investment for children and the middle-aged households' financial preparation for retirement and investigated factors influencing financial preparation for retirement. Data were obtained from the 3rd Korean Retirement and Income Study (KReIS) in 2009, and a sample of 757 households was selected. The statistical methods were frequency, percentile, mean, standard deviation, ${\chi}^2$, t-test, Pearson's correlation coefficient, and logistic regression analysis. The findings of this study are as follows. First, the percentile of preparation for living costs for old age was 49.9% for the middle-aged households. In terms of the types of preparation for living costs for old age, the results showed 61.6% of personal preparation, 33.9% of pension system, and 1.3% for children and relatives. In relation to the adequacy of the preparations for living costs for old age, preparations made by 57.4% of the middle-aged households were inadequate. Observing the minimum living costs for old age and adequate living costs after retirement for single and couple, the minimum living costs of the middle-aged households was 1.46 million won for couple and 0.91 million won for single. The adequate living costs for old age was 2.07 million won for couple and 1.34 million won for single. Second, there were 757 households with total education expenditure. Of these, 208 incurred annual expenditure on public education, and the annual expenditure for public education was 7.28 million won. There were 170 households with annual expenditure for private education, and the annual expenditure for private education was 2.50 million won. 243 households of middle-aged households had annual expenditure for human capital investment, including both public and private education, with annual expenditure for human capital investment for children of 7.82 million won. Furthermore, in the human capital investment factor, there was a difference in the middle-aged households' financial preparation for retirement according to their annual expenditure for human capital investment including both public and private education. In addition, there was a difference in financial preparation for retirement based on their public education expenditure. Third, in the logistic regression model 1, which included human capital investment, the significant variables affecting the preparation for retirement of the middle-aged households were as follows : annual household income, total amount of annual household income, experience of inadequate living costs, existence of financial assets, total amount of annual household savings, financial independence, adequate living costs (for single) for old age, and human capital investment. In the logistic regression model 2, which included annual expenditure for public education and annual expenditure for private education, the significant variables affecting the preparation for retirement of the middle-aged households were as follows : annual household income, total amount of annual household income, experience of inadequate living costs, existence of financial assets, total amount of annual household savings, financial independence, adequate living costs (for single) for old age, and annual expenditure for public education.

• The Journal of the Acoustical Society of Korea
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• 제18권3E호
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• pp.37-43
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• 1999

In this paper, we present a new technique for the optimal local decomposition of convex structuring elements on a hexagonal grid, which are used as templates for morphological image processing. Each basis structuring element in a local decomposition is a local convex structuring element, which can be contained in hexagonal window centered at the origin. Generally, local decomposition of a structuring element results in great savings in the processing time for computing morphological operations. First, we define a convex structuring element on a hexagonal grid and formulate the necessary and sufficient conditions to decompose a convex structuring element into the set of basis convex structuring elements. Further, a cost function was defined to represent the amount of computation or execution time required for performing dilations on different computing environments and by different implementation methods. Then the decomposition condition and the cost function are applied to find the optimal local decomposition of convex structuring elements, which guarantees the minimal amount of computation for morphological operation. Simulation shows that optimal local decomposition results in great reduction in the amount of computation for morphological operations. Our technique is general and flexible since different cost functions could be used to achieve optimal local decomposition for different computing environments and implementation methods.

• 가족자원경영과 정책
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• 제16권3호
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• pp.153-176
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• 2012

This study gives an account of the state of baby-boomer households in regard to assets and liabilities utilizing the 2006 Household Asset Survey and the 2011 Survey of Household Finances. Using the data gathered from each year, this study examined the proportion of households who had each type of asset and liability, and the amount of them. This study also compared the amount of assets and liabilities of baby-boomer households with those of non baby-boomer households in 2006 and 2011 respectively. Finally, this study examined the amount of change and composition ratio of assets and liabilities of baby-boomer households between 2006 and 2011. Selected financial ratios were also presented for both years. Major findings are as follows. The average asset amount for baby-boomer households was approximately 296 million in 2006 and 392 million in 2011. Of total assets, 78% and 76.5% were real assets in 2006 and 2011 respectively. The average financial assets of 2006 baby-boomer households were approximately 66 thousand and the average amount of debt was 42 thousand. For 2011 baby-boomer households, the average amount of financial assets was 92 thousand and the average amount of debt was 73 thousand. Results from the 2011 survey showed that baby-boomer households had a significantly higher proportion of total assets, total debt, and net worth than non baby-boomer households. The proportion of savings, saving insurance, stocks, and mutual funds were significantly higher for baby-boomer households than non baby-boomer households in 2011. In regard to financial ratios, the emergency fund index and debt burden index were appropriate to the guidelines of asset quality, although the propensity to investment indexes were not.