• 자원환경지질
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• 제32권1호
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• pp.1-11
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• 1999

In the last decade, the supply of natural aggregates has been continuously increased due to the other types of aggregates. In general, aggregates constitute 70-80% of the total volume of concrete, so the quality of aggregates is main factor controlling physical characteristics of concrete. For this reason, physical properties of aggregate according to different rock types were studied. The majority of crushed aggregates is taken out of granite, gneiss, sandstone, andesite, basalt and so forth. The physical properties of these rock types were tested and most of them fell within the acceptable limit on the base of Korean standard regulation. The major lithology of the crushed aggregates is granite and gneiss, both of which are marked for more than 50% of total lithology thpes in Korea. A to the physical properties of granite, the high specific gravity coincides with low porosity, low absorption ratio, while the abrasion and soundness index show, in general, no specific trend. It has been assumed that slight differences of the physical properties of granite aggregates are related with those of the mineral composition, grain size, and so on. In comparison to granite, the physical properties of gneiss have little correlation one after another. This trend is related to different mineral composition, grain size and typical sheet fractures typically prevailing in the texture of gneiss. Spatial pattern of physical properties shows that high specific gravity of granite coincides only with low porosity and absorption ratio in all provinces except Cheolla province, and high specific gravity of gneiss coincides with low porosity and absorption ratio only in Cheolla and Gandwon provinces.

• 한국시스템다이내믹스연구
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• 제13권2호
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• pp.47-71
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• 2012

The purpose of this research is the examination of validity of data as well as simulation model, i.e. to simulate the real data in the SD model with the least error using the adjustments for the faithful reflection of real data to the simulation. In general, SD programs (e.g. VENSIM) utilize the Euler or Runge-Kutta method as an algorithm. It is possible to reflect the trend of real data via these two estimation methods however can cause the validity problem in case of the simulation requiring the accuracy as they have endogenous errors. In this article, the future population estimated by the Korea National Statistical Office (KNSO) to 2050 is simulated by the aging chain model, dividing the population into three cohorts, 0-14, 15-64, 65 and over cohorts by age and offering the adjustments to them. Adjustments are calculated by optimization with three different methods, optimization in EXCEL, manual optimization with iterative calculation, and optimization in VENSIM DSS, the results are compared, and at last the optimal adjustment set with the least error are found among them. The simulation results with the pre-determined optimal adjustment set are validated by methods proposed by Barlas (1996) and other alternative methods. It is concluded that the result of simulation model in this research has no significant difference from the real data and reflects the real trend faithfully.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 춘계 학술논문 발표대회 1부
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• pp.61-62
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• 2011

This study reviewed the effect of W/B, WO and curing method on the quality properties of RA using the BS brick under the zero cement condition. compressive strength was found to show an increasing trend as W/B increased, but to show a improvement in case steam curing was conducted, showing a higher increase at 1 day age in comparison with 7 day age. In addition, the compressive strength on the mixing of WO didn't show any specific trend. The absorption tended to decrease as W/B increased and met the less than 10% regulation value at 30~35% W/B in case WO was used, there appeared a decrease attributable to capillary pore filling effect due to saponification. On the other hand, compressive strength increases, th absorption showed a gradually decreasing tendency.

• 대한가정학회지
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• 제45권5호
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• pp.39-49
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• 2007

The purpose of this study was 1) to segment the middle-aged and elderly women's fashion market based on the clothing benefits sought by the buyer and 2) to compare the purchase criteria and fashion information sources among the segmented markets. The data were collected using a self-administered questionnaire in Seoul and its surrounding suburban areas. Factor analysis, ANOVA, Duncan test, and Dunnett's T3 tests were used to conduct the data analysis from 285 out of 300 questionnaires. The middle-aged and elderly women's fashion market was segmented into four groups; value-oriented, social status/trend-oriented, uniqueness-oriented, and protection/ convenience-oriented. All four groups were significantly different in terms of purchase criteria and fashion information sources. The social status/trend-oriented group used external purchase criteria, such as country of origin or brand and obtained fashion information from personal experience, advice from the salesperson, and celebrities. The protection/convenience-oriented group sourced fashion information from newspapers, the internet, and the radio. The uniqueness-oriented group put less importance on practical use/convenience criteria. Marketing strategies for these segmented markets were discussed.

• 한국측량학회지
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• 제33권3호
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• pp.193-202
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• 2015

The greenbelt of South Korea has been under the process of adjustment and removal since its first designated year. This research is aimed at predicting the effect that the removal of the greenbelt has on urban growth. The SLEUTH model was executed via three calibration phases using historical data between 1990 and 2010. The urban growth of Busan Metropolitan City was predicted under its historical trend, as well as two different scenarios including development and compact development up to the year 2030. The accuracy of model, as verified by ROC, was 85.7%. The historical trend scenario showed the smallest increase, with the urban area expanding from 175.96 km² to 214.68 km² in 2030. Scenario 2, the development scenario, showed the most increase, with a 39.9% growth rate from 2010 to 2030. However, according to scenario 3, the compact development scenario, the urban area decreased in comparison to scenario 2. Accordingly, it is necessary to have effective urban growth management to provoke eco-friendly development on the removed areas, and to strengthen the non-removed areas for sustainable development. The results obtained in this study showed that the SLEUTH model can be useful for predicting urban growth, and that it can help policy makers establish proper urban planning as a decision-support tool for sustainable development.

• Journal of Information Processing Systems
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• 제15권3호
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• pp.694-706
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• 2019

In this study, we applied the long short-term memory (LSTM) model to classify the cryptocurrency price time series. We collected historic cryptocurrency price time series data and preprocessed them in order to make them clean for use as train and target data. After such preprocessing, the price time series data were systematically encoded into the three-dimensional price tensor representing the past price changes of cryptocurrencies. We also presented our LSTM model structure as well as how to use such price tensor as input data of the LSTM model. In particular, a grid search-based k-fold cross-validation technique was applied to find the most suitable LSTM model parameters. Lastly, through the comparison of the f1-score values, our study showed that the LSTM model outperforms the gradient boosting model, a general machine learning model known to have relatively good prediction performance, for the time series classification of the cryptocurrency price trend. With the LSTM model, we got a performance improvement of about 7% compared to using the GB model.

• 대기
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• 제29권1호
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• pp.53-59
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• 2019

The quality of troposphere ozone in three reanalysis datasets is evaluated with longterm ozonesonde measurement at Pohang, South Korea. The Monitoring Atmospheric Composition and Climate (MACC), European Centre for Medium-Range Weather Forecasts Interim Reanalysis (ERAI) and Modern Era Retrospective-Analysis for Research and Applications version 2 (MERRA2) are particularly examined in terms of the vertical ozone structure, seasonality and long-term trend in the lower troposphere. It turns out that MACC shows the smallest biases in the ozone profile, and has realistic seasonality of lower-tropospheric ozone concentration with a maximum ozone mixing ratio in spring and early summer and minimum in winter. MERRA2 also shows reasonably small biases. However, ERAI exhibits significant biases with substantially lower ozone mixing ratio in most seasons, except in mid summer, than the observation. It even fails to reproduce the seasonal cycle of lower-tropospheric ozone concentration. This result suggests that great caution is needed when analyzing tropospheric ozone using ERAI data. It is further found that, although not statistically significant, all datasets consistently show a decreasing trend of 850-hPa ozone concentration since 2003 as in the observation.

• 한국식생활문화학회지
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• 제37권3호
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• pp.196-212
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• 2022

This study examines the trend of research on food and culture in papers published in the Journal of The Korean Society of Food Culture from 1986 to 2020. The journals published a total of 329 papers, which we classified into 5 main categories and 13 middle categories. Of these, 204 articles were on "Korean traditional food culture." The most studied topic in the entire period was "Perception of Koreans towards traditional food, preference, satisfaction, and usage." A total of 76 studies related to "Korean contemporary food culture." The most advanced topic researched concerned "Recognition and attitude"; these studies were consistently carried out throughout the research period. The main classification of "World food culture" encompassed 32 studies, with major research focused on "World's Modern Food Culture" and the most advanced being "Comparison of Food Cultures of Foreign and Korean Food Cultures." All studies were consistently spaced out during the study period. These studies provide an integrated knowledge in the field of food and culture and can be used as a basic material for related research in the future.

• International Journal of Computer Science & Network Security
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• 제23권9호
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• pp.37-46
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• 2023

The main aim of the article is to solve the problem of automating price monitoring using marketing forecasting methods and Excel functionality under martial law. The study used the method of algorithms, trend analysis, correlation and regression analysis, ANOVA, extrapolation, index method, etc. The importance of monitoring consumer price developments in market pricing at the macro and micro levels is proved. The introduction of a Dummy variable to account for the influence of martial law in market pricing is proposed, both in linear multiple regression modelling and in forecasting the components of the Consumer Price Index. Experimentally, the high reliability of forecasting based on a five-factor linear regression model with a Dummy variable was proved in comparison with a linear trend equation and a four-factor linear regression model. Pessimistic, realistic and optimistic scenarios were developed for forecasting the Consumer Price Index for the situation of the end of the Russian-Ukrainian war until the end of 2023 and separately until the end of 2024.

• 한국콘텐츠학회논문지
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• 제9권12호
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• pp.710-717
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• 2009

연구동향을 분석하기 위해서 일반적으로 연구자와 기획자는 특허맵/논문맵 분석을 이용하고 있으나, 한의학계의 특수성으로 기존 시스템을 이용할 수 없는 상황이다. 그래서 선행연구와 선행시스템을 파악하여 적용 가능한 분석모델을 도출하여 한의학 관련 연구동향을 체계적으로 분석할 수 있는 기본분석, 상세분석, 복합분석의 14개 모델을 설계하였다. 약 16,000건의 한의학 논문이 수록되어 있는 오아시스 데이터베이스에 '경락'의 키워드를 사용하여 103건의 논문을 검색하였다. 추출된 논문에 제안된 분석모델을 적용하여 한의학의 경락 연구는 성숙기에 접어들고 있으며 생리학 등 타 분야와 밀접한 관련이 있는 결과를 얻었으며, 선행 시스템의 분석모델과의 비교를 통해서 제안된 분석모델을 검증하였다. 개발된 분석모델은 한의학 논문맵 분석 시스템을 위한 서비스 시나리오 개발 및 시스템 구현에 이용될 수 있을 것으로 기대된다.