• Journal of the Korean Data Analysis Society
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• v.20 no.6
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• pp.2917-2932
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• 2018

Many researches are accomplished as a result of the efforts of developing the production predicting model to solve the supply imbalance of onions which are vegetables very closely related to Korean food. But considering the possibility of storing onions, it is very difficult to solve the supply imbalance of onions only with predicting the production. So, this paper's purpose is trying to build a sentiment dictionary to predict the price of onions by using the internet articles which include the informations about the production of onions and various factors of the price, and these articles are very easy to access on our daily lives. Articles about onions are from 2012 to 2016, using TF-IDF for comparing with four kinds of TF-IDFs through the documents classification of wholesale prices of onions. As a result of classifying the positive/negative words for price by k-means clustering, DBSCAN (density based spatial cluster application with noise) clustering, GMM (Gaussian mixture model) clustering which are partitional clustering, GMM clustering is composed with three meaningful dictionaries. To compare the reasonability of these built dictionary, applying classified articles about the rise and drop of the price on logistic regression, and it shows 85.7% accuracy.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.2
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• pp.1-13
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• 2015

Traffic volume data is basic information that is used in a wide variety of fields. Existing missing traffic volume data imputation method did not take the effect on the rainfall. This research analyzed considering of the rainfall effect in missing traffic volume data imputation method. In order to consider the effect of rainfall, established the following assumption. When missing of traffic volume data generated in rainy days it would be more accurate to use only the traffic volume data of the past rainy days. To confirm this assumption, compared for accuracy of imputed results at three kinds of imputation method(Unconditional Mean, Auto Regression, Expectation-Maximization Algorithm). The analysis results, the case on consideration of the rainfall effect was more low error occurred.

• Journal of Korea Water Resources Association
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• v.33 no.S1
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• pp.720-725
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• 2000

• Proceedings of the Korea Water Resources Association Conference
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• 2000.05a
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• pp.720-725
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• 2000

• 한국해양학회지
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• v.23 no.4
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• pp.169-183
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• 1989

Polychaete assemblages and their responses to habitat conditions were investigated in the southeastern continental shelf of Korea. The result of cluster analysis revealed that the study area could be divided into two regions, one including the shallow coastal region and the other the offshore region. The shallow coastal region sustained 4 polychaete assemblages: Nothria holobranchiata assemblage in the most northern part of fine sediments off Pohang, Magelona-Maldane assemblage off Gampo, Ophelina acuminata assemblage in the middle coastal area off Ulsan, Nothria conchylega assemblage in the south part off Pusan. These coastal polychaete assemblages contained less than 10 species per station and showed very low species diversity (H' = 1.22-1.52). The offshore also contained 4 assemblages: Terebellides-Aglaophamus assemblage in the northern and deep area of very fine sediments, Myriochele oculata and Spiophanes kroyeri assemblages in the central area of sandy bottoms, and Ninoe palmata assemblage in the southern offshore of sandy bottom. The offshore assemblages showed rather more species and higher diversity than coastal assemblages (H' = 1.90-2.26). The offshore region consisting of sandy sediment showed very low population densities. Some dominant species showed specific preference to sediment types and this phenomenon could be detected through their feeding modes. Depth or bottom temperature seems to be related to the distribution of most dominant worms. Thus the polychaete assemblages of the study area are found to be under the control of both a gradient of sedimentary properties and that of bottom temperature.

• Journal of Korean Society of Transportation
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• v.36 no.2
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• pp.67-85
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• 2018

Vehicle platooning through wireless communication and automated driving technology has become realized. Platooning is a technique in which several vehicles travel at regular intervals while maintaining a minimum safety distance. Truck platooning is of keen interest because it contributes to preventing truck crashes and reducing vehicle emissions, in addition to the increase in truck flow capacity. However, it should be noted that interactions between vehicle platoons and adjacent manually-driven vehicles (MV) significantly give an impact on the performance of traffic flow. In particular, when vehicles entering from on-ramp attempt to merge into the mainstream of freeway, proper interactions by adjusting platoon size and inter-platoon spacing are required to maximize traffic performance. This study developed a methodology for establishing operational strategies for truck platoonings on freeway on-ramp areas. Average speed and conflict rate were used as measure of effectiveness (MOE) to evaluate operational efficiency and safety. Microscopic traffic simulation experiments using VISSIM were conducted to evaluate the effectiveness of various platooning scenarios. A decision making process for selecting better platoon operations to satisfy operations and safety requirements was proposed. It was revealed that a platoon operating scenario with 50m inter-platoon spacing and the platoon consisting of 6 vehicles outperformed other scenarios. The proposed methodology would effectively support the realization of novel traffic management concepts in the era of automated driving environments.

• Korean Journal of Environment and Ecology
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• v.6 no.1
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• pp.25-43
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• 1992

A survey of Orimok, Yongsil and Donnaeko area forest in Mt. Halla. was conducted using 71 sample plots of 500$m^2$ size. In the analysis of -actual vegetation, Carpinus tschonoskii and C. laxiflora community covered 53.7%, Quercus grosseserrata - Q. serrata community 25.8%, Pinus densiflora community 8.3%, Abies koreana community 4.5% and these communities covered 92.2% of Mt. Halla forest. The degree of 8, 9 and 10 in human disturbance of vegetation covered 64.5, 28.6 and 6.9% respectively. The classification by TWINSPAN and DCA ordination were applied to the study area in order to classify them into several groups based on woody plants and environmental variables. By two techniques, the plant community were divided into several groups by the aspect and altitude. The dividing groups are C. tschonoskii community, C. tschonoskii - Q. serrata community, P. densiflora - C. tschonoskii community, P. densiflora - C. laxiflora community, C. laxiflora community, C. laxifrora - Daphniphyllum macropodum - Eurya japonica community, P. densiflora community. The successional trends of tree species by both techniques seem to be from P. densiflora. Sorbus alnifolia through Q. serrata. Maackia faurier to C. tsihonoskii in Orimok and Yongsil area and from P. densifiora to C. laxiflora in Donnaeko area. There was no difference between the stand scores of. DCA and environmental variables.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.480-490
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• 2018

This study investigated the profiles of anger expression (anger control, anger in, anger out) and their variation in forms, and determined the differences in depression, aggression, and negative affect intensity of middle school students. For this purpose, the survey responses of 296 middle school students in Seoul were analyzed. The major study results are as follows. (1) Cluster analyses yielded four anger expression profiles: cluster 1 was characterized by high scores for anger control, anger in and anger out, cluster 2 by low scores for anger control, high scores for anger in and anger out, cluster 3 by low scores for anger control, anger in and anger out, and cluster 4 by low scores for anger in, high scores for anger control and anger out. (2) Between-cluster differences in depression, aggression, and negative affect intensity were all significant. The posteriori test indicated that cluster 4 was higher than the other three clusters in terms of depression. Cluster 3 was higher than the other three clusters on aggression, cluster 2 was higher than cluster 4 in terms of aggression. The interventions by aggression expression cluster are discussed and the implications of this research to education and counseling are explained.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.3
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• pp.119-131
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• 2010

Drought is one of disaster causing factors to produce severe damage in the World because drought is destroyed to the ecosystem as well as to make difficult the economy of the drought area. This study, using Palmer Drought Severity Index carries out correlation analysis with sea surface temperatures. Comparative analysis carries out by calculated Palmer Drought Severity Index and past drought occurrence year. Result of comparative analysis, PDSI indexes were in accord with the past drought. Cluster analysis for correlation analysis carries out using precipitation and temperature that is input datas palmer drought severity index, and the result of cluster analysis was classified as 6. Also, principal component carries out using result of cluster analysis. 14 principal component analyze out through principal component analysis. Using analyzed 14 principal component carries out correlation analysis with sea surface temperature that is delay time from 0month until 11month. Correlation analysis carries out sea surface temperatures and calculated cycle component of the low frequency through Wavelet Transform analysis form principal component. Result of correlation analysis, yang(+) correlation is bigger than yin(-) correlation. It is possible to check similar correlation statistically the area of sea surface temperature with sea surface temperature in the Pacific. Forecasting possibility of the future drought make propose using sea surface temperature.

• Korean Journal of Environment and Ecology
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• v.32 no.1
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• pp.39-46
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• 2018

Breeding bird surveys provide the reference information for understanding bird community structure and function in the ecosystem and conserving biodiversity. Recent rapid change of biodiversity due to climate change and other factors has made it necessary to utilize acoustic sensors for accuracy and spatial expansion of forest bird survey data and for time-series monitoring of forest birds. The objective of this study is to investigate the possibility of using acoustic recording sensor to evaluate the diversity of forest birds at breeding season by comparing and analyzing the recorded data of bird songs and field bird survey data. We conducted the site survey and recording in 186 points in 48 areas of 4 regions of Gombaeryeong and Jochimryeong around Jeombongsan Mountain and Jugryeong and Gochiryeong around Sobaeksan Mountain from May 2nd to 16th in 2013. The analysis of the correlation between the recording result and Bird Community Index based on the field survey showed that the number of bird species, population, and the number of bird songs by recording was significantly correlated to the number of species and population by field survey. Moreover, the number of bird species and the number of bird songs by recording showed a significant correlation to species diversity and species richness but no or low significant correlation to species evenness by the field study (observation and listing in parallel). As a result, it was possible to check species composition and species diversity of bird communities by analyzing acoustic recording data on the field. The acoustic recordings of bird songs in the breeding period were more reliable than the non-breeding period in the correlation of recording result and species diversity and for utilization.