• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.2
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• pp.306-312
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• 2022

During the unprecedented COVID-19 outbreak, the public's information needs created an environment where they overwhelmingly consume information on the chronic disease. Given that news media affect the public's emotional well-being, the pandemic situation highlights the importance of paying particular attention to how news stories frame their coverage. In this study, COVID-19 news speech emotion from mainstream broadcasters in South Korea and the United States (US) were analyzed using convolutional neural networks. Results showed that neutrality was detected across broadcasters. However, emotions such as sadness and anger were also detected. This was evident in Korean broadcasters, whereas those emotions were not detected in the US broadcasters. This is the first quantitative vocal emotion analysis of COVID-19 news speech. Overall, our findings provide new insight into news emotion analysis and have broad implications for better understanding of the COVID-19 pandemic.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.9
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• pp.1357-1366
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• 2022

It is important to quickly and accurately build a disaster network or tactical mobile communication network adapting to the field. In configuring the traditional wireless communication systems, the parameters of the base station are set through cell planning. However, for cell planning, information on the environment must be established in advance. If parameters which are not appropriate for the field are used, because they are not reflected in cell planning, additional optimization must be carried out to solve problems and improve performance after network construction. In this paper, we present a rapid mobile communication network construction and optimization method using artificial intelligence and SON technologies in mobile communication base stations. After automatically setting the base station parameters using the CNN model that classifies the terrain with path loss prediction through the DNN model from the location of the base station and the measurement information, the path loss model enables continuous overage/capacity optimization.

• Journal of Advanced Navigation Technology
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• v.27 no.5
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• pp.502-509
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• 2023

This study presents a satellite constellation method that achieves optimal revisit performance by utilizing genetic algorithm techniques. The Walker method is a global coverage concept, and there are limitations to target-centered constellation considering the strategic environment of the Korean Peninsula. To overcome these limitations, targets are set in major areas of interest in North Korea, orbit elements with optimal revisit performance for each target are searched, and based on this, the number of satellites optimized for each target is derived using a genetic algorithm. The results of this study demonstrate the performance of the optimized constellation by applying phasing rules to achieve the desired revisit performance.

• Journal of Ecology and Environment
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• v.47 no.4
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• pp.250-260
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• 2023

Background: Crabgrass (Digitaria ciliaris, Poaceae) is a globally distributed weed, including in Afro-Eurasia, America, and Australia. As a highly gregarious plant, crabgrass is an important habitat for a diverse array of insects, and a potential habitat for agricultural pests. To compare the insect communities associated with the crabgrass community, insects were sampled using sweep sampling (100 sweeps per sample) at five sites, including Daejeon (Daejeon and Gap rivers), Anseong, Namhae, and Inje, with a focus on the Daejeon River. Results: A total of 5,888 individual insects belonging to eight orders, 42 families, and 115 species were collected from the five sites. Both the number of species and individuals of Hemiptera were the highest at all of the sites. In the present study, 73% of the insect population fed on D. ciliaris as a host plant. The dominant species in the D. ciliaris community was Laodelphax striatellus (Delphacidae), being ubiquitous at all the sites which showed a high abundance of rice pests in the communities and the suitability of D. ciliaris as an alternative host plant for them. The Shannon-Wiener diversity index was highest in Inje on 17 September (2.88), and the Chao1-bc diversity index was highest in the Gap River on 5 September (80). The sampling efficiency of 100 sweep samples (sample coverage) was calculated to be as high as 90%. The results of the samples taken from September to November in the Daejeon River showed that the number of species and individuals decreased gradually over time, and the number of dominant species decreased sharply between September and October. Similarity analysis indicated that sampling dates that were closer together yielded sampled assemblages with higher faunal similarity. In addition, in each sampling, the difference in the minimum temperature during the two-week period prior to sampling and faunal similarities were negatively correlated. Conclusions: This study provides foundational data that could enhance our understanding of insect diversity in D. ciliaris. The data can facilitate ecological conservation and management of Korean grasslands generally, as well as identification of potential pests that may disperse from D. ciliaris communities to nearby farmland.

• Korean Journal of Environment and Ecology
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• v.25 no.1
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• pp.17-30
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• 2011

This study has analyzed the vegetation composition in the areas using different slope revetment techniques of riverbanks, in a way to improve the vegetation induction in the future considering the ecological aspects of the induction in Garaeyoul Village, Gangdong-gu, Seoul. The result of the vegetation distribution in each different slope revetment technique was analyzed, that the naturalized herb was dominant in the pole block accounting for 70.7%, while native herb was dominant in the lawn block occupying 48.5% and in the crib block occupying 55.7%. The vegetation coverage measured by different slope revetment techniques was highest in the crib block(average 97.5%), followed by the lawn block(average 95.3%) and pole block(average 27.9%). The vegetation base area was the most wide in the crib block and the most narrowest in the pole block. The result of community analysis in areas using different slope revetment techniques, dry herbs and vine herbs were dominated and the coverage was very poor in the pole block. In the lawn block, the barb was fragmented into narrow areas due to the blocks, which prevented the creation of large-scale plant communities. In the crib block, Miscanthus sacchariflorus, Fescue arundinacea and Aster pilosus, which also consisted of large-scale communities. Average dry weight was also measured by each slope revetment technique. The weight was heaviest in the crib block with $187.63g/m^2$, followed by the lawn block($137.65g/m^2$) and pole block($6.75g/m^2$). The soil moisture contents in the crib block and lawn block was 16.3% and 15.2%, respectively, while that of the pole block was 4.7%, which revealed the highly dry condition of the pole block soil. The analysis result of soil chemical property showed that there was little difference in soil texture, soile acidity(pH), and exchangeable ion content, however, the soil organic matter(OM) content and available $P_2O_5$ were highest in the pole block. In the future, in order to induce more vegetation into river banks and walls, a proper construction method should be applied so that the vegetation area can be expanded as much as possible, considering the safety of the banks.

• Korean Journal of Ecology and Environment
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• v.49 no.3
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• pp.197-207
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• 2016

This study aims at providing basic data to objectively evaluate the areas suitable for reintroduction of the species of Asiatic black bear (Ursus thibetanus) in order to effectively preserve the Asiatic black bears in the Korean protection areas including national parks, and for the species restoration success. To this end, this study predicted the potential habitats in East Asia, Southeast Asia and India, where there are the records of Asiatic black bears' appearances using the Maxent model and environmental variables related with climate, topography, road and land use. In addition, this study evaluated the effects of the relevant climate and environmental variables. This study also analyzed inhabitation range area suitable for Asiatic black and geographic change according to future climate change. As for the judgment accuracy of the Maxent model widely utilized for habitat distribution research of wildlife for preservation, AUC value was calculated as 0.893 (sd=0.121). This was useful in predicting Asiatic black bears' potential habitat and evaluate the habitat change characteristics according to future climate change. Compare to the distribution map of Asiatic black bears evaluated by IUCN, Habitat suitability by the Maxent model were regionally diverse in extant areas and low in the extinct areas from IUCN map. This can be the result reflecting the regional difference in the environmental conditions where Asiatic black bears inhabit. As for the environment affecting the potential habitat distribution of Asiatic black bears, inhabitation rate was the highest, according to land coverage type, compared to climate, topography and artificial factors like distance from road. Especially, the area of deciduous broadleaf forest was predicted to be preferred, in comparison with other land coverage types. Annual mean precipitation and the precipitation during the driest period were projected to affect more than temperature's annual range, and the inhabitation possibility was higher, as distance was farther from road. The reason is that Asiatic black bears are conjectured to prefer more stable area without human's intervention, as well as prey resource. The inhabitation range was predicted to be expanded gradually to the southern part of India, China's southeast coast and adjacent inland area, and Vietnam, Laos and Malaysia in the eastern coastal areas of Southeast Asia. The following areas are forecast to be the core areas, where Asiatic black bears can inhabit in the Asian region: Jeonnam, Jeonbuk and Gangwon areas in South Korea, Kyushu, Chugoku, Shikoku, Chubu, Kanto and Tohoku's border area in Japan, and Jiangxi, Zhejiang and Fujian border area in China. This study is expected to be used as basic data for the preservation and efficient management of Asiatic black bear's habitat, artificially introduced individual bear's release area selection, and the management of collision zones with humans.

• The Korean Journal of Ecology
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• v.28 no.5
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• pp.305-320
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• 2005

Recently 64 species in Korea have been ranked as rare and endangered taxa by the Ministry of Environment using two categories, I and II. The original threat categories produced by the Ministry of Environment were developed to provide a standard for specifying animals and plants in danger of extinction and has been influential sources of information used in species conservation in Korea. However, the criteria by Ministry of Environment were applied to the whole taxa only by regional boundaries, especially in South Korea, rather than international context, and it also lacked an explicit framework that was necessary to ensure repeatability among taxa because of the absence of quantitative criteria to measure the likelihood of extinction. The World Conservation Union (IUCN) has developed quantitative criteria for assessing the conservation status of species. The threatened species categories, the 2000 IUCN Red List, proposed by SSC (Species Survival Commission) of IUCN have become widely recognized internationally. Details of threatened Korean plants, identified by applying the IUCN threat categories and definitions, were listed and analyzed. The number of species identified as threatened was only 34 out of 64 taxa (48.4%), while the rest of taxa were rejected from the original lists. Many of the species (51.6%, 33 taxa) excluded from the original list proposed by Ministry of Environment do not qualify as Critically Endangered, Endangered or Vulnerable because these taxa were widely distributed either in Japan or in China/far eastern Russia and there is no evidence of substantial decline in these countries. An evaluation of taxa in Korea has been carried out only based on subjective views and qualitative data, rather than quantitative scientific data, such as rates of decline, distribution range size, population size, and risk of extinction. Therefore, the national lists undermine the credibility of threatened species lists and invite misuse, which have been raised by other cases, qualitative estimate of risk, political influence, uneven taxonomic or geographical coverage. The increasing emphasis on international responsibilities means that global scale is becoming more significant. The current listings by Environment of Ministry of Korea should be challenged, and the government should seek to facilitate the resolution of disagreements. Especially the list should be flexible enough to handle uncertainty and also incorporates detailed, quantitative data. It is suggested that the highest priorities for the Red List should be given to endemic species in Korea first. After setting up the list of endemic species to Korea, quantitative data on population size and structure, distributional range, rated of decline, and habitat fragmentation should be collected as one of long term projects for the Red list categories. Transparency and accountability are the most important key factors. Also, species assessors are named and data sources referenced are required for the future objective evaluations on Korean plant taxa.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.34 no.3
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• pp.28-37
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• 2016

Through the research and analysis on the hydrological environment and soil environment of habitats through documentary and field studies over 14 habitats of Euryale ferox Salisb. within Jeollabukdo, with the objective of acquiring the basic data for forming an environment based on plantation of reservoirs that are composed with Euryale ferox, the following results were obtained. As a result of analyzing the construction period of the habitats of Euryale ferox from a total of 14 places, the average period of duration after construction of all subject reservoirs appeared to be 71.8 years. Moreover, when examining the relationship between the age of reservoirs and eutrophication, it could be judged that at least the eutrophication of subsoil and water environment is not an obstacle to the growth of Euryale ferox grows in habitats that have a reservoir age of approximately 70 years or more. As a result of analyzing the gardening of soil sediment of the Euryale ferox habitats, the component ingredients appeared to be composed of 80.2% of clay, 16.7% of silt and 3.1% of sand, and the soil class pursuant to such was classified as 'heavy clay'. The organic matter contents of soil sediment appeared to be an average of 36g/kg, and there appeared to be no noticeable difference between the habitats and non-habitats of Euryale ferox. The water quality environment of Euryale ferox habitat appeared to be pH 6.5~7.9, concentration of dissolved oxygen to be $1.8{\sim}8.8mg/{\ell}$, concentration of COD to be $6.8{\sim}74mg/{\ell}$, floating materials to be $2.0{\sim}213mg/{\ell}$, total nitrogen to be $0.422{\sim}10.723mg/{\ell}$, and phosphate to be $0.003{\sim}0.126mg/{\ell}$. The average DO concentration of Aedang Reservoir at Jeongeup, Daejeong Reservoir at Imsil, and Myeongdeokji at Gimje with high vitality and green coverage ratio of Euryale ferox appeared to be $3.5mg/{\ell}$, total nitrogen to be $1.33mg/{\ell}$, and concentration of phosphorus-phosphate to be $0.061mg/{\ell}$. When comparing such with the entire average value, the DO and total nitrogen concentration appeared to be rather low, and the phosphorus-phosphate concentration appeared to be higher by two times or more, thus, an in-depth study on the correlation of the vitality of Euryale ferox Salisb. and concentration of phosphorate-phosphorus will be needed in the future.

• Korean Journal of Environment and Ecology
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• v.16 no.2
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• pp.141-148
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• 2002

This study was carried out to estimate the effect of forest fire on herb layer development and chemical properties of soil. The forest fire was in April 2000 in Pinus rigida(softwood) and Robinia pseudoacacia(hardwood) dominant forests at Gaejoksan, Daejeon. Vegetation studies were in the two communities and herb layer development study was in July using dominance of Dierssen. The coverage of herb layer was higher in the burned area than in the unburned area in the two study communities. There was no different herb layer species number between the burned and unburned areas, but there was different herb layer species number between the two communities. Soil samples were collected at 0～10cm and 10～20cm soil depths from the unburned and burned sites after 3 days and 8 months of forest fire. There was no forest floor in burned site, but unburned site has the forest floor of 1.5cm thick. There were no significant differences in soil organic matter, total N, available P, exchangeable K, Ca, Na, and Mg, and CEC, pH in all soil depth, between unburned and burned sites after 3 days of forest fire and between burned site after 3 days and 8 months of forest fire, except in organic matter in 10～20cm soil depth in hardwood sites and in exchangeable Ca in the 10～20cm soil depth, and in Mg in the two soil depths in hardwood sites. It seems to be that forest fire had not changed the chemical soil properties in this study.

• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.1
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• pp.1-8
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• 2013

This study focuses on a ship detection and tracking method using Frequency Modulated Continuous Wave (FMCW) radar used for horizontal surveillance. In general, FMCW radar can play an important role in maritime surveillance, because it has many advantages such as low warm-up time, low power consumption, and its all weather performance. In this paper, we introduce an effective method for data and signal processing of ship's detecting and tracking using the X-band radar. Ships information was extracted using an image-based processing method such as the land masking and morphological filtering with a threshold for a cycle data merged from raw data (spoke data). After that, ships was tracked using search-window that is ship's expected rectangle area in the next frame considering expected maximum speed (19 kts) and interval time (5 sec). By using this method, the tracking results for most of the moving object tracking was successful and those results were compared with AIS (Automatic Identification System) for ships position. Therefore, it can be said that the practical application of this detection and tracking method using FMCW radar improve the maritime safety as well as expand the surveillance coverage cost-effectively. Algorithm improvements are required for an enhancement of small ship detection and tracking technique in the future.