• 한국경영과학회지
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• 제40권1호
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• pp.91-116
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• 2015

This study aims to provide public sectors with eco-efficiency information. To implement the purposes of the study, environmental and economic variables of Eco-Efficiency were identified through decision tree model, then the relative Eco-Efficiencies of 243 public sectors were evaluated through input-oriented DEA (Data Envelopment Analysis) model. Specifically, the amount of public purchasing per a staff and the amount of energy use per a staff were considered as input factors. Sales per a staff was considered as output factor. The result shows that most of the public sectors (94.2%) were evaluated as "inefficient" taking into consideration of average value, 0.501 from market-based public corporations, 0.288 from local public corporations, 0.28 from quasi-market-based public corporations, 0.269 from fund-management-based quasi-governmental institutions, 0.09 from non-classified public institutions, and 0.078 from commissioned-service-based quasi-governmental institutions. Furthermore, it is possible to establish a plan for internal Eco-Efficiency improvement based on information of the reference set. In order to improve the Eco-Efficiency in the public sectors in the long term, environmental impacts of the overall public sectors' operations (e.g., energy saving, water saving, waste reduction, and purchasing of green products) needs to be properly proposed in consideration of BSC (Balanced Scorecard) indicators of public sectors.

• 가정과삶의질연구
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• 제24권5호
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• pp.251-270
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• 2006

This study examined how the households used and combined financing sources to pay for college education. It compared the probability of using each source (current incomes, saving, education loans and grants) by households' socio-economic characteristics and analyzed which factors influence the decision to use each source and the amounts from each source for financing college education. Data for this study were from a questionnaire completed by 4-year college students (n=623) and were analyzed by t-tests, ANOVA and Heckman's two-step estimation models. The findings of this study were as follows: First, the most frequent source for college education was parents' savings and the second one was parents' incomes. Also, the most frequent combination of sources was saving and current incomes and the second was combination of three sources, saving, incomes and education loans. Second, the probability of using incomes was higher for younger students than for older students. The number of siblings showed significant differences among income, savings and education loans. Those who had higher incomes were more likely to use current incomes, saving, but less likely to borrow for financing college education. Middle-class income groups were more likely to borrow for education. Third, household incomes and asset holdings had generally positive impacts on the probability of using incomes and savings for college education, while total debt burden decreased both the probability and amounts of income and saving sources. The college costs had significantly positive effects on both the probability and the amounts of all of financing sources. Total grants received significantly decreased the amounts from incomes, savings and borrowing sources.

• ETRI Journal
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• 제34권6호
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• pp.807-815
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• 2012

In this paper, we propose a scheme for partially dynamic lane control for energy saving in multilane-based high-speed Ethernet. In this scheme, among the given transmission lanes, at least one lane is always operating, and the remaining lanes are dynamically activated to alleviate the network performance in terms of queuing delay and packet loss in the range of acceptance. The number of active lanes is determined by the decision algorithm based on the information regarding traffic and queue status. The reconciliation sublayer adjusts the transmission lane with the updated number of lanes received from the algorithm, which guarantees no processing delay in the media access control layer, no overhead, and minimal delay of the exchanging control frames. The proposed scheme is simulated in terms of queuing delay, packet loss rate, lane changes, and energy saving using an OPNET simulator. Our results indicate that energy savings of around 55% (or, when the offered load is less than 0.25, a significant additional savings of up to 75%) can be obtained with a queuing delay of less than 1 ms, a packet loss of less than $10^{-4}$, and a control packet exchange time of less than $0.5{\mu}s$ in random traffic.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2010년도 한국컴퓨터종합학술대회논문집 Vol.37 No.1(D)
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• pp.360-365
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• 2010

In this paper, we present a distributed algorithm for detecting dynamic event regions in wireless sensor network with the consideration on energy saving. Our model is that the sensing field is monitored by a large number of randomly distributed sensors with low-power battery and limited functionality, and that the event region is dynamic with motion or changing the shape. At any time that the event happens, we need some sensors awake to detect it and to wake up its k-hop neighbors to detect further events. Scheduling for the network to save the total power-cost or to maximize the monitoring time has been studied extensively. Our scheme is that some predetermined sensors, called critical sensors are awake all the time and when the event is detected by a critical sensor the sensor broadcasts to the neighbors to check their sensing area. Then the neighbors check their area and decide whether they wake up or remain in sleeping mode with certain criteria. Our algorithm uses only 2 bit of information in communication between sensors, thus the total communication cost is low, and the speed of detecting all event region is high. We adapt two kinds of measure for the wake-up decision. With suitable threshold values, our algorithm can be applied for many applications and for the trade-off between energy saving and the efficiency of event detection.

• 가정과삶의질연구
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• 제19권1호
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• pp.111-129
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• 2001

This study was performed to develope a money management education program for elementary school students graded from 3 to 6 in order to enhance their money management skill. Based on the developmental stages of the children, this program covered five financial issues such as value of money, financial planning, allowance planning, saving and investment, and consuming and purchasing. Total 15 specific education programs were developed. The contents included in each program were value of money & economic circulation, types of money and the importance of money management, the issues related on choice and resource use, long-term and short-term planning, the relationship between occupation and earnings, career planning, budgeting, the reasons and types of saving, understanding of interest, investment methods, the functions of market and trade, intra family income distribution, consumptions, and consumer decision making process.

• Journal of Advanced Marine Engineering and Technology
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• 제11권1호
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• pp.39-52
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• 1987

Recently, the design problem of heat insulation have been reappraised in the aspect of energy saving due to the rising trend of energy cost. For example, that design problem is increasingly requsted in the fields of accommodation air conditioning systems, hot water supply systems, cargo handling systems, district heating or cooling systems. The rational design of heat insulation of piping systems can not only improve the overall efficiency of energy transfer but also give energy saving. In this paper, the heat insulation problem of district heating systems is therefore modeled as the multi-stage decision processes, suitable for dynamic programming technique. And take the object function as the sum of heat insulation material cost involved construction cost and heat loss cost, and propose the design method to minimize the object function for overall piping systems by dynamic programing. Effectiveness of design method presented here is proved by a computer simulation.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2000년도 학술발표회 발표논문집
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• pp.181-186
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• 2000

Recently a strong request for the improvement in irrigation water management in order to flexibly meet the spacial and time changes of water demand for agricultural and other uses by saving agricultural water. Thereby, the purpose of this study is to design of Basin Water Management Program(BWMP). BWMP is operate with Open Control System. Accordingly, BMWP is easy to acquire data and control irrigation and drainage facilities. BWMP are consist of Data Base Management System(DBMS) and Model System. DBMS make it possible to analyze data related with planing for water schedul and establish database. Model System are calculate reservoir inflow, reservoir effluent and basin water demand. Finally, operator is decide reservoir operation in consider of Model System and DBMS. BWMP might be nicely adapted to the planning and decision for saving water.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.1540-1547
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• 2009

Steel frame factories were surveyed in this study in order to explore the possibility of shortening the construction time and save on construction cost through overlapping at the stages of design or construction. In the survey, construction professionals were interviewed in order to collect quantitative data. Hypotheses were then formulated, and the data was thereby analyzed using the simulation technique in order to analyze the effects of the concurrent engineering method on shorter construction time and cost saving. In addition, actual cases were analyzed to determine the overlapping rates of major processes in terms of shorter construction time and cost saving and to analyze the relationship between time and cost due to overlapping.

• 한국통신학회논문지
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• 제33권1C호
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• pp.34-44
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• 2008

본 논문에서는 H.264 부호화기에서 고속의 율-왜곡 최적화된 모드 결정을 위한 효과적인 율-왜곡 예측 방식을 제안한다. 비트율과 왜곡치가 최소가 되는 율-왜곡 최적화된 모드를 결정하기 위해서는 각 매크로 블록 모드를 부호화하고 복호화 하여 비트율과 왜곡치를 계산해야 한다. 이 과정에서 요구되는 계산량을 줄이고자 DCT 영역에서 비트율과 왜곡치를 효과적으로 예측하는 방식을 제안한다. 모의실험 결과는 제안 방식을 이용하여 모드 결정을 하였을 때 율-왜곡 성능은 거의 유지되면서 H.264의 율-왜곡 최적화된 모드 결정 계산량의 약 81%를 감소시키고 전체 부호화 계산량의 약 26%를 감소시킴을 보여준다.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2004년도 제5회 정기학술발표대회 논문집
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• pp.515-520
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• 2004

최근 건설산업은 구조물의 일부 또는 전체를 대상으로 제조업의 체계적인 생산시스템인 공장생산방식을 활용하여 생산성을 향상시키기 위한 방안을 마련하고 있다. 하지만 효과를 검증하지 않고 무조건적으로 공장생산방식을 도입한다면 생산 규모와 위치에 따라 현장생산보다 공사비용이나 공기가 증가되는 경우도 있다. 공장생산방식을 보다 효과적으로 활용하기 위해서는 공장생산방식과 현장생산방식을 다양한 기준으로 비교해본 후 적용여부에 대한 의사결정이 이루어져야한다. 본 연구는 기존의 연구와 사례분석을 통하여 공장생산방식의 적용에 필요한 의사결정요인을 도출하고 이를 고려한 의사결정모델을 제시하고자한다 크게 3단계의 연구방법을 거쳐 의사결정을 내릴 수 있는 의사결정순서도와 의사결정모형도를 작성하였다. (1) 공장생산방식 적용 의사결정요인을 도출하고 구조화하여 (2) 공장생산의 규모와 공장의 위치의 변화에 따른 이익, 비용, 공기를 산출한 후 (3) 현장생산방식과 공장생산방식을 반복적으로 비교함으로써 의사결정을 내릴 수 있는 모델을 제시하였다.