• Korean Journal of Construction Engineering and Management
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• v.22 no.4
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• pp.59-65
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• 2021

Since the 2016 "Housing Act Partial Amendment" and the "2018 Housing Comprehensive Amendment Plan", interest in the pre sale system and post sale system of apartment houses has been on the rise. In order to compare the advantages and disadvantages of the pre sale system and the post sale system of apartment houses, and to establish the basis for the institutional policy of the post sale system, a questionnaire survey method was used for tenants of the apartment house from the public side, and issues of time and cost. The time series analysis method is intended to suggest an appropriate time for payment of contributions. Accordingly, through a review of existing theories and literature, the post sale system of public and private institutions was organized, and through a questionnaire survey, the path to securing pre sale money, product information of the model house, and the degree of awareness of the effect of the post sale system were investigated. For the post sale fund support and payment method, it is necessary to increase the commercial line for existing financiers from the user's point of view, and it is necessary to operate in consideration of the economic power of the pre sale market by region. Both 60% post sale and 80% post sale have a price range of up to KRW 10 million, and the total interest rate is 5.0%, and the annual interest rate is about 2.8% for 60% post sale, and about 2.1% for 80% post sale, which is lower than the current 3.1%. I need an interest rate. The research is a perception survey targeting a total of 5,213 households in a sample of after sale apartments in public institutions. As the actual values are analyzed using a time series on the effects of market supply and demand and market prices, there is a limit to applying them to prospective residents of private apartments. In addition, to respond to first time tenants, a questionnaire survey was conducted on five complexes that have moved in within the last five years.

• Journal of the Korean Association of Geographic Information Studies
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• v.12 no.2
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• pp.34-43
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• 2009

Based on previous research on ways of reducing an urban heat island phenomenon via an introduction of wind corridors, I conducted this study to see what influence a change in land cover arising of or going through urbanization has on wind corridors of urban space. As a target place, I chose Daegu city where is a representative extreme heat place in Korea and has been also largely expanded in size by incorporating its neighboring areas since the 1980s, expecially Dalseo District whose surface temperature gap is large. The population of Dalseo District has been sharply increased since its creation as a new administrative district in 1988. I studied on the urban microclimate change for a 20-year period by using satellite images on summer months in 1987, 1997 and 2007 in time frames. The finding of this study found that a reduction of natural land cover and an increase of artificial land cover serves as a disadvantageous factor for cold air creation and flowing and strikingly lowers the amount and height of cold air in the downtown area. It seemed that the cold air creation and flowing functions are influenced by land cover. In order to steadily create cold air and secure its flowing, it is thought that urban development or urban regeneration should be implemented by analysing the characteristics of the space surrounding the city. By doing so, a pleasant and healthy city could be formed.

• The Journal of Engineering Geology
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• v.24 no.2
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• pp.217-225
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• 2014

Water curtain cultivation (WCC) systems in Korea have depleted water resources in shallow aquifers through massive pumping of groundwater. The goal of this study is to simulate the groundwater variations observed from massive groundwater pumping at a site in Cheongweon. MODFLOW was used to simulate three-dimensional regional groundwater flow, and the SWAT (Soil and Water Assessment Tool) watershed hydrologic model was employed to introduce temporal changes in groundwater recharge into the MODFLOW model input. Additionally, the estimation method for groundwater discharge in WCC areas (Moon et al., 2012) was incorporated into a groundwater pumping schedule as a MODFLOW input. We compared simulated data and field measurements to determine the degree to which winter season groundwater drawdown is effectively modeled. A simulation time of 107 days was selected to match the observed groundwater drawdown from November, 2012 to March, 2013. We obtained good agreement between the simulated drawdown and observed groundwater levels. Thus, the estimation method using daily minimum temperatures, may be applicable to other cultivation areas and can serve as a guideline in simulating the regional flow of riverside groundwater aquifers.

• The Korean Journal of Applied Statistics
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• v.31 no.4
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• pp.427-446
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• 2018

Korea will have a super-aged society within only 30 years according to the United Nations' definition of an aging society and the statistics on Korea's Population projections (2016), indicates that Korea has the fastest ageing speed in the world. There is a lack of data on long-term time-series data on death as related to pension and welfare policies compared to the rapid rate of aging. This paper estimates life expectancy over 245 years (from 1955 to 2200) through past and future forecasts as well as compares the expected life expectancy of the synthetic cohort and the real cohort. In addition, an international comparisons were made to understand the level of aging in Korea. Estimates of the back-projection period were compared with previous studies and the LC model to improve accuracy and objectivity. In addition, the predictions after 2016 reflected the declined mortality rate effect of Korea using the LC-ER model. The results showed an increase in life expectancy of about 30 years over 60 years (1955-2015) with an expected life expectancy of the real cohort over the second century (1955-2155) higher than the synthetic cohort. The comparative advantage of life expectancy of real cohorts was confirmed to be a common trend among comparative countries. In addition, Japan and Korea have a higher life expectancy and starting from 85 to 90 years old, all comparative countries show that the growth rate for the life expectancy of synthetic and real cohorts is less than previous years.

• Journal of Technology Innovation
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• v.19 no.1
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• pp.1-27
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• 2011

This paper aims to measure and analyze R&D productivities and efficiencies of 17 major OECD countries including Korea over the 1984-2008 period by using the Malmquist Productivity Index and Data Envelopment Analysis, classifying R&D performance into an output and outcome aspects. It also searches the Korea's current status and characteristics in each R&D stage to enhance Total Factor Productivity (TFP) compared with other developed countries. Our major findings are the followings: (i) Korea's productivity index of R&D input vis-a-vis R&D output is very high (13.39% annual growth rate) compared with those of major advanced countries, whereas the annual average of efficiency index is very low (0.33), i.e. Korea's technical efficiency index has risen to 0.83 at the last time series started at 0.10 point and come up to the level of major advanced countries. (ii) the Korea's productivity index of R&D output vis-a-vis R&D outcome is very low (14.02% annual reduction rate) compared with those of major advanced countries, whereas the annual average of efficiency index is very high (0.22), i.e. Korea's integrated frontier technical efficiency index has dropped to 0.057 at the last time series started at 1.00 point and coming up to the level of major advanced countries. (iii) The productivity of R&D input vis-a-vis R&D outcome is positively correlated with that of R&D output vis-a-vis R&D outcome and the growth of R&D input factors. In a nutshell, it implicates that the effort to take advantage of R&D outputs, namely establishing the diffusion and commercialization system of technical knowledge to the level of developed countries, should be strengthened over that on the growth of R&D investment and output for enhancing R&D productivity and efficiency in Korea.

• Journal of Technology Innovation
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• v.25 no.1
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• pp.61-89
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• 2017

This study aims to estimate empirically the respective impacts of R&D expenditure, R&D labor, overseas direct investment, commodity trade balance, and technology trade openness on technology balance of payments. To examine the presence of co-integration between them, this paper employed the ARDL-bounds test using time series data from 1981 to 2014, and the result shows that there is a stable long-run equilibrium relationship among them. Furthermore, we estimated long- and short-run coefficients of the technology balance of payments with respect to each variables based on long-run equilibrium equation and error correction model. As a result, the technology balance of payments respond negatively to R&D labor and technology trade openness, and R&D expenditure does produce positive effects in the long-run, while coefficients of overseas direct investment and commodity trade balance in the long-run are not statistically significant. Besides, according to results of error correction model, overseas direct investment only has clearly a positive effects in the short-run, in contrast, the short-term relationships between the other variables and the technology balance of payments could not definitively derived. This implies that it is necessary to procure and cultivate talented personnel, as well as to enlarge gradually technology trade size in order to improve technology balance of payments from a long-term point of view.

• Journal of Korea Water Resources Association
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• v.44 no.4
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• pp.295-304
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• 2011

For effective water quality management, it is necessary to secure reliable water quality information. There are many variables that need to be included in a comprehensive practical monitoring network : representative sampling locations, suitable sampling frequencies, water quality variable selection, and budgetary and logistical constraints are examples, especially sampling location is considered to be the most important issues. Until now, monitoring network design for water quality management was set according to the qualitative judgments, which is a problem of representativeness. In this paper, we propose network design system for optimal water quality monitoring using the scientific statistical techniques. Network design system is made based on the SAS program of version 9.2 and configured with simple input system and user friendly outputs considering the convenience of users. It applies to Excel data format for ease to use and all data of sampling location is distinguished to sheet base. In this system, time plots, dendrogram, and scatter plots are shown as follows: Time plots of water quality variables are graphed for identifying variables to classify sampling locations significantly. Similarities of sampling locations are calculated using euclidean distances of principal component variables and dimension coordinate of multidimensional scaling method are calculated and dendrogram by clustering analysis is represented and used for users to choose an appropriate number of clusters. Scatter plots of principle component variables are shown for clustering information with sampling locations and representative location.

• Journal of Korea Water Resources Association
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• v.45 no.11
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• pp.1157-1168
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• 2012

In this study, we assess changes in water quality trends over time based on certain control measurements in order to identify and analyze the cause of the trend in water quality. The current water pollution in the Nakdong River was analyzed, as it suggests that the significant changes in water quality have occurred in between 2006 and 2010. Based on monthly average data, we have examined for trends of the Nakdong River watershed in water temperature, Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Nitrogen (TN), and Total Phosphorus (TP). Moreover, we have investigated seasonal variation of water quality of sites within the Nakdong River Basin by implementing further analyses such as, Correlation Coefficient, Regression Analysis, Hierarchical Clustering Method, and Time Series Analysis on SPSS. Geology and topography of the watershed, controlled by various conditions such as, climate, vegetation, topography, soil, and rain medium, have been affected by the non-homogeneity. Our study suggests that such variables could possibly cause eutrophication problems in the river. One possible way to overcome this particular problem is to lay up a ship on the river by increasing the nasal flow measurement of the Nakdong River during rainy season. Moreover, the water management requires arranging the measurement of the flow in order to secure the river while the numerous construction projects need to be continuously observed. However, the water is not flowing tributary of the reason for the timing to be flowing in a natural state of river water and industrial water intake because agriculture. Therefore, ongoing research is needed in addition to configuration of all observations.

• Korean Journal of Cognitive Science
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• v.11 no.1
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• pp.1-8
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• 2000

Most of the important visual information is presented to driver through the display panel that is related to the vehicle. If display panel is designed with the c consideration of driver's visibility, drivers can get broad visual field and visual I information related to vehicle promptly and exactly during driving situation. Therefore display panel has direct relationship with the driver's task performance and it can be considered as an important device that affects the driver-automotive interaction. Many r researches about shape, characteristic and color of display panel have been performed, but not sufficient in this country Nowadays most of vehicles has an analog type display. but its shape and arrangement a are various without any definite standards about position. Therefore. experiments using evaluation tool (VISVEC System) were conducted to inquire the driver's preference on the major objects arrangement of display panel (speedometer. tachometer. fuel meter. and t thermometer) and to ascertain the factors that have an effect on drivers according to the objects position of the display panel The experiment results showed that there was no correlation between the arrangement c characteristics preferred by subjects and the cognitive accuracy but the cognition of V visual information more easy when the each major object has its area.

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.10
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• pp.293-302
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• 2016

Since the electricity is produced and consumed simultaneously, predicting the electric load and securing affordable electric power are necessary for reliable electric power supply. In particular, a university campus is one of the highest power consuming institutions and tends to have a wide variation of electric load depending on time and environment. For these reasons, an accurate electric load forecasting method that can predict power consumption in real-time is required for efficient power supply and management. Even though various influencing factors of power consumption have been discovered for the educational institutions by analyzing power consumption patterns and usage cases, further studies are required for the quantitative prediction of electric load. In this paper, we build an electric load forecasting model by implementing and evaluating various machine learning algorithms. To do that, we consider three building clusters in a campus and collect their power consumption every 15 minutes for more than one year. In the preprocessing, features are represented by considering periodic characteristic of the data and principal component analysis is performed for the features. In order to train the electric load forecasting model, we employ both artificial neural network and support vector machine. We evaluate the prediction performance of each forecasting model by 5-fold cross-validation and compare the prediction result to real electric load.