• Spatial Information Research
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• v.22 no.3
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• pp.89-99
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• 2014

The aim of this study is to represent the residential population distribution in Seoul, Korea more precisely through the dasymetric mapping method. Dasymetric mapping can be defined as a mapping method to calculate details from truncated spatial distribution of main statistical data by using ancillary data which is spatial data related to the main data. In this research, there are two types of data used for dasymetric mapping: the population data (2010) based on a output area survey in Seoul as the main data and the building footprint data including register information as ancillary spatial data. Using the binary method, it extracts residential buildings as actual areas where residents do live in. After that, the regression method is used for calculating the weights on population density by considering the building types and their gross floor areas. Finally, it can be reproduced three-dimensional density of residential population and drew a detailed dasymetric map. As a result, this allows to extract a more realistic calculating model of population distribution and draw a more accurate map of population distribution in Seoul. Therefore, this study has an important meaning as a source which can be applied in various researches concerning regional population in the future.

• Journal of Korea Multimedia Society
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• v.8 no.3
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• pp.297-312
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• 2005

Aggregation is an operation that plays a key role in multidimensional OLAP (MOLAP) systems of data warehouse. Existing aggregation operations in MOLAP have been proposed for file structures such as multidimensional arrays. These tile structures do not work well with skewed distributions. This paper presents a physical design methodology for storage structures ni MOLAP that use the multidimensional tile organizations adapting to a skewed distribution. In uniform data distribution, we first show that the performance of multidimensional analytical processing is highly affected by the similarity of the shapes between query regions and page regions in the domain space of the multidimensional file organizations. And than, in skewed distributions, we reflect the effect of data distributions on the design by using the shapes of the normalized query regions that are weighted with data density of those query regions. Finally, we demonstrate that the physical design methodology theoretically derived is indeed correct in real environments. In the two-dimensional file organizations, the results of experiments indicate that the performance of the proposed method is enhanced by more than seven times over the conventional method. We expect that the performance will be more enhanced when the dimensionality is more than two. The result confirms that the proposed physical design methodology is useful in a practical way.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.05a
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• pp.273-280
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• 2005

Robust magneto-telluric (MT) response function estimators are now in standard use in electromagnetic induction research. Properly devised and applied, these methods can reduce the influence of unusual data (outlier) in the response (electric field) variable, but often not sensitive to exceptional predictor (magnetic field) data, which are termed leverage points. A bounded influence estimator is described which simultaneously limits the influence of both outlier and leverage point, and has proven to consistently yield more reliable MT response function estimates than conventional robust approach. The bounded influence estimator combines a standard robust M-estimator with leverage weighting based on the statistics of the hat matrix diagonal, which is a standard statistical measure of unusual predictors. Further extensions to MT data analysis are proposed, including a establishment of data rejection criterion which minimize the influence of both electric and magnetic outlier in frequency domain based on statistical distribution of electromagnetic field. The rejection scheme made in this study seems to have an effective performance on eliminating extreme data, which is even not removed by BI estimator, in frequency domain. The effectiveness and advantage of these developments are illustrated using real MT data.

• Fire Science and Engineering
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• v.15 no.4
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• pp.24-33
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• 2001

This article proposes a strategy for producing accident scenarios in quantitative risk, which is peformed in process design or operation steps. Present worldwide chemical processes need off-site risk assessment as well as on-site one. Most governments in the world require industrial companies to submit the proper emergency plans through off-site risk assessment. Korea is also preparing for executing Integrated Risk Management System along with PSM and SMS. However.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.12
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• pp.2221-2229
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• 2006

Optimal path search algorithm which is a killer application of mobile device to utilize location information should consider traffic flows of the roads as well as the distance between a departure and destination. The existing path search algorithms, however, are net able to cope efficiently with the change of the traffic flows. In this paper, we propose a new optimal path search algorithm. The algorithm takes the current flows into consideration in order to reduce the cost to get destination. It decomposes the road network into Fixed Grid to get variable heuristics. We also carry out the experiments with Dijkstra and Ar algorithm in terms of the execution time, the number of node accesses and the accuracy of path. The results obtained from the experimental tests show the proposed algorithm outperforms the others. The algorithm is highly expected to be useful in a advanced telematics systems.

• The Korean Journal of Applied Statistics
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• v.27 no.4
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• pp.629-643
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• 2014

It is common to check the validity of an assumed model with the heavy use of diagnostics tools when conducting data analysis with regression techniques; however, outliers and influential data points often distort the regression output in undesired manner. Jang and Anderson-Cook (2013) proposed a graphical method called a firework plot for exploratory analysis that could visualize the trace of the impact of possible outlying and/or influential data points on individual regression coefficients and the overall residual sum of squares(SSE) measure. They developed 3-D plot as well as pair-wise plot for the appropriate measures of interest. In this paper, the approach was extended further to tell the strength of their approach; in addition, a more meaningful interpretation was possible by adding a measure not mentioned in their paper. This approach was applied to the mixture experiment because we felt that a detailed analysis of statistical measure sensitivity is required in a small experiment.

• Journal of the Korean Society for information Management
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• v.35 no.1
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• pp.231-250
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• 2018

In this paper, we propose a new methodology for extracting and formalizing subjective topics at a specific time using a set of keywords extracted automatically from online news articles. To do this, we first extracted a set of keywords by applying TF-IDF methods selected by a series of comparative experiments on various statistical weighting schemes that can measure the importance of individual words in a large set of texts. In order to effectively calculate the semantic relation between extracted keywords, a set of word embedding vectors was constructed by using about 1,000,000 news articles collected separately. Individual keywords extracted were quantified in the form of numerical vectors and clustered by K-means algorithm. As a result of qualitative in-depth analysis of each keyword cluster finally obtained, we witnessed that most of the clusters were evaluated as appropriate topics with sufficient semantic concentration for us to easily assign labels to them.

• The Journal of Korean Association of Computer Education
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• v.11 no.6
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• pp.1-9
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• 2008

The goal of the education of Information Communication Ethics(ICE) is to improve the consciousness level of adolescents so that they themselves are able to judge between what's ethically right and wrong and, as a result, to take the right behavior. For this, we need to preferentially identify the primary factors in understanding and diagnosing the consciousness level of adolescents on the ICE. To solve this problem, in this paper, we identified four major indices that consist of the ICE consciousness through the meta analysis of the both domestic and international researches from the past 5 years in the related area and then, they are validated by experts. We also analyzed the factors in assessing the ICE consciousness level of adolescents by using the Delphi technique, which, during its analysis, even considers elements that are qualitative or cannot be objectified. Finally we deduced 22 ICE factors given the weight through the AHP of an expert group that consists of experienced teachers and professors in the related area.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.3
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• pp.557-565
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• 2015

Sea level rise due to global warming causes seawater intrusion into aquifers in coastal areas. Seawater intrusion vulnerability index was developed using PSR (Pressure, State, Response) model and analysis hierarchy process (AHP). Coastal regions in Korea, Gangwon-do Sokcho-si, Incheon-si Ganghwa-gun, Chungcheongnam-do Taean-gun, Jeollanam-do Yeosu-si, Jindo-gun were chosen and 14 indicators were selected by considering the humanities, economic, social, environmental aspects. Re-scaling method was used for the standardization of indices and questionnaire survey was performed to calculate weight values for each index. The results showed that Yeosu-si was selected as the most vulnerable region to seawater intrusion. The seawater intrusion index developed in this research can be used to analyze the vulnerable regions to seawater intrusion and to establish a policy to minimize the seawater intrusion problems in coastal regions.

• Journal of Korean Society for Geospatial Information Science
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• v.18 no.2
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• pp.99-105
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• 2010

Photovoltaic system is the core one among the new and renewable energy of the low Carbon and green growth. Recently, the necessity developing PV is emerging since its of less green hose gas emissions. However, a survey or research on the PV system has been hardly performed. It's not easy to find a appropriate location in consideration of environment. These circumstances encourages a systematic approach for the PV system development. The purpose of this study is to propose a methodology of the location analysis for developing PV system. With this, constraint and location criteria with weights of Analytic Hierarchy Process are established and quantification method of each factor is presented. The location analysis of PV system using the GIS were generalized and the results of analysis for redundant topographic features were presented as 3 criteria of the suitability rank.