• KDI Journal of Economic Policy
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• 제40권1호
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• pp.1-30
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• 2018

Ongoing demographic changes have brought about a substantial shift in the size and age composition of the population, which are having a significant impact on the global economy. Despite potentially grave consequences, demographic changes usually do not take center stage in many macroeconomic policy discussions or debates. This paper illustrates how demographic variables move over time and analyzes how they influence macroeconomic variables such as economic growth, inflation, savings and investment, and fiscal balances, from an empirical perspective. Based on empirical findings-particularly regarding inflation-we discuss their implications on macroeconomic policies, including monetary policy. We also highlight the need to consider the interactions between population dynamics and macroeconomic variables in macroeconomic policy decisions.

• Journal of Communications and Networks
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• 제12권2호
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• pp.114-121
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• 2010

In this paper, an auctioning strategy is proposed for cellular networks that ensures net energy savings. The pricing scheme, in conjunction with a two dimensional bid structure, incentivizes cooperation at the terminal nodes for better interference management at receivers and for cooperative relaying. It is shown that, for the proposed auctioning strategy, network operators are guaranteed revenue gains, mobile nodes' dominant strategy is to bid their true valuation of their energy resources, and overall effective energy gains occur under the assumption of a reserve price for bidding. Simulation results show that significant energy savings can be achieved by employing this auctioning mechanism for a 3G cellular set-up.

• 제어로봇시스템학회논문지
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• 제6권10호
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• pp.936-941
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• 2000

Advanced space transportation systems, such as the National Aerospace Plane or an Orbital Transfer Vehicle, have atmospheric maneuvering capabilities. For such vehicles the use of aeroassisted orbital transfer from a high Earth orbit to a low Earth orbit, with unpowered flight in the atmosphere, has the potential for significant fuel savings compared to exoatmospheric Hohmann transfer. However, to exploit the fuel savings that can be achieved by using the Earths atmosphere to reduce the vehicles energy, a guidance law is required, and it must be able to handle large unpredictable fluctuations in atmospheric density, on the order of ${\pm}$50% relative to the 1962 US Standard Atmosphere. In this paper aeroassisted orbital transfer is considered as a differential game, with Nature controlling the atmosphere density to yield a worst case (min-max fuel required) atmosphere, from which the guaranteed playable set boundary are achieved. Inside the playable set, it is guaranteed that the vehicle achieves the optimal atmospheric exit condition for the minimum fuel consumption regardless of the atmospheric density variations.

• 대한전자공학회논문지
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• 제25권6호
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• pp.629-636
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• 1988

The reduction of recovery time for delay, in the train movements, is generally realized through train operations in the shortest running time and it leads to maximum energy consumption. At the region of this shortest running time, the amount of energy consumption is sharply reduced according to the running time. So the effect for the energy savings can be largely obtained by furnishing a little spare time on train operations. In this paper, it has been modelized the delay and it's enlargement phenomena and formualted the relief patterns in order to restore the delay by restraint and relief of precedent traints. Also it has been proved the number of relief trains for minimum energy consumption exists and then represented one example of relief patterns.

• 가족자원경영과 정책
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• 제18권1호
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• pp.93-114
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• 2014

This study aims to investigate the levels of assets and debts that male- and female-headed households have in comparison to married-couple households. Toward this end, a series of analyses of data from the 2011 Korean Household Finance Survey on the assets and debts of single-parent households are conducted. The empirical results reveal that the amounts of assets and net worth of married-couple households were significantly larger than those of male- and female-headed households. A comparison between male- and female-headed households show that the latter were more likely to hold financial assets such as savings accounts, savings insurance and mutual funds. The amounts of assets of female-headed households were significantly larger than those of male-headed households. Furthermore, the amount of credit card debt in mele-headed households was significantly larger than that in female-headed households.

• 대한가정학회지
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• 제43권1호
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• pp.85-103
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• 2005

This study attemped to analyze the financial stati of single households. The financial stati of single households were analyzed using the income and expense stati, balance sheet status and selected financial ratios as components. The data of 757 single household's from the 1998 Korean Household Panel Study were utilized. The major findings are summarized as follows; 1. Male single households had higher income and expense stati than those of females but lower holdings of other asset with the exception of liquid assets. Single elderly households had the highest holdings of both real assets and debt. 2. Usually single households were retained more short-term than long-term liquid assets. The debt burden ability in using net assets was the lowest of all assets. To accumulate capital those in single household were more likely to have savings than investment assets.

• 자연, 터널 그리고 지하공간
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• 제22권1호
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• pp.26-35
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• 2020

Tunnelling to bypass major landslide areas is considered as a good and long-term environmentally friendly solution to reduce an existing hazard. In Norway, hundreds of kilometres of tunnels have been constructed in areas prone to landslides and snow avalanches. Although tunnelling is considered as an expensive mitigation strategy for bypassing landslides, analysis indicate that in some cases the cost of building a tunnel can be repaid by savings in driving costs (fuel) alone over a period of 5-10 years due to reduced driving distances. The other benefits of constructing tunnels in landslide areas include savings in time and increased safety. The Norwegian Method of Tunnelling (NMT) is considered safe, efficient and cost effective compared to other tunnelling techniques. Some aspects of NMT, which are considered safe and cost efficient, are presented. The application of updated rock support techniques, including reinforced ribs of shotctrete (RRS), which is a key component of the Norwegian Method of Tunnelling (NMT), is highlighted.

• Journal of applied mathematics & informatics
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• 제5권1호
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• pp.191-200
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• 1998

There are two types of composition systems for the Korean alphabet: a combined system and a composite system. This paper decribes an efficient coding method for both of these two types. Using this coding method with the combined system yields about 10.5% code-length savings per a Korean character while it yields about 45% savings with the composite system. In other words the coding method produces a better result(i.e. 34.5% better) with the composite system than with the combined system. The simulation has been performed on a MasPar machine having 64 processors. The results show that the combined system achieved a 45.851-fold speedup while the composite system achieved a 47.274-fold speedup.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.1925-1928
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• 2007

Water cycle analysis was performed for Gunja basin located in metropolitan Seoul using Aquacycle model in order to assess the problems of urban water cycle. From the water cycle analysis of Gunja basin, it was found that 75% of total rainfall occurred in the form of surface runoff, and groundwater recharge only accounted for about 7%. This suggests serious distortion of water cycle which can be attributed to urbanization. Feasibility analysis of reuse scenarios such as rainwater use and wastewater reuse was then performed to examine their influences on improving the water cycle. From the analysis of water reuse options, it was shown that imported water supply savings of 13% can be achieved through rainwater use, and water supply savings of 31% through wastewater reuse.

• 대한가정학회지
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• 제39권8호
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• pp.121-136
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• 2001

The purpose of this study was to analyze the effects of financial attitudes and financial communication on financial satisfaction. For this study, in 2000, questionnaires developed by the researcher were given to 320 households in Kwangju. resulting in 262 households with usuable data. The data were analyzed by various statistical methods such as frequency, percentile, correlation analysis, t-test, Anova, Multiple Regression analysis. The major findings of this study were as follows; 1) Financial attitudes were significantly different according to age and monthly savings 2) Financial communication was significantly different according to age and financial subjective variables. 3) Financial satisfaction was significantly different according to monthly income, monthly savings, monthly living costs, debt, financial subjective variables and financial communication. The set of socio- economic characteristics variables accounted for 3% of the variance in the financial satisfaction. But the addition of subjective characteristics variables, financial attitude, financial communication resulted in an $R^2$ change of 20, 23, 26%.