• Korean Journal of Ecology and Environment
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• v.57 no.2
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• pp.92-101
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• 2024

Current distribution of Korean Cottus pollux was investigated by conducting field surveys and environmental DNA analysis in September to November 2022 and March to May 2023. As a result of the field survey, the presence of C. pollux was confirmed in the uppermost stream of Hyeongsangang River, as well as in Deokdongcheon, Jeolgolcheon, and Hoamcheon Streams. The main habitat of C. pollux was the riffle area in the upper reaches of streams with clean water and boulder-cobble bottoms. As a result of environmental DNA analysis, the samples determined to be positive included all streams in which the presence of C. pollux was confirmed in the field survey. In addition, Namcheon and Singwangcheon Streams were determined to be positive, indicating potential as its habitats. Since C. pollux has a narrow distribution area and a small population size, continuous monitoring and conservation measures are required to immediately respond to damage caused by typhoons and river works, which are the main causes of habitat disturbance, in order to maintain a stable population.

• Journal of Intelligence and Information Systems
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• v.21 no.1
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• pp.143-159
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• 2015

Predicting IT trends has been a long and important subject for information systems research. IT trend prediction makes it possible to acknowledge emerging eras of innovation and allocate budgets to prepare against rapidly changing technological trends. Towards the end of each year, various domestic and global organizations predict and announce IT trends for the following year. For example, Gartner Predicts 10 top IT trend during the next year, and these predictions affect IT and industry leaders and organization's basic assumptions about technology and the future of IT, but the accuracy of these reports are difficult to verify. Social media data can be useful tool to verify the accuracy. As social media services have gained in popularity, it is used in a variety of ways, from posting about personal daily life to keeping up to date with news and trends. In the recent years, rates of social media activity in Korea have reached unprecedented levels. Hundreds of millions of users now participate in online social networks and communicate with colleague and friends their opinions and thoughts. In particular, Twitter is currently the major micro blog service, it has an important function named 'tweets' which is to report their current thoughts and actions, comments on news and engage in discussions. For an analysis on IT trends, we chose Tweet data because not only it produces massive unstructured textual data in real time but also it serves as an influential channel for opinion leading on technology. Previous studies found that the tweet data provides useful information and detects the trend of society effectively, these studies also identifies that Twitter can track the issue faster than the other media, newspapers. Therefore, this study investigates how frequently the predicted IT trends for the following year announced by public organizations are mentioned on social network services like Twitter. IT trend predictions for 2013, announced near the end of 2012 from two domestic organizations, the National IT Industry Promotion Agency (NIPA) and the National Information Society Agency (NIA), were used as a basis for this research. The present study analyzes the Twitter data generated from Seoul (Korea) compared with the predictions of the two organizations to analyze the differences. Thus, Twitter data analysis requires various natural language processing techniques, including the removal of stop words, and noun extraction for processing various unrefined forms of unstructured data. To overcome these challenges, we used SAS IRS (Information Retrieval Studio) developed by SAS to capture the trend in real-time processing big stream datasets of Twitter. The system offers a framework for crawling, normalizing, analyzing, indexing and searching tweet data. As a result, we have crawled the entire Twitter sphere in Seoul area and obtained 21,589 tweets in 2013 to review how frequently the IT trend topics announced by the two organizations were mentioned by the people in Seoul. The results shows that most IT trend predicted by NIPA and NIA were all frequently mentioned in Twitter except some topics such as 'new types of security threat', 'green IT', 'next generation semiconductor' since these topics non generalized compound words so they can be mentioned in Twitter with other words. To answer whether the IT trend tweets from Korea is related to the following year's IT trends in real world, we compared Twitter's trending topics with those in Nara Market, Korea's online e-Procurement system which is a nationwide web-based procurement system, dealing with whole procurement process of all public organizations in Korea. The correlation analysis show that Tweet frequencies on IT trending topics predicted by NIPA and NIA are significantly correlated with frequencies on IT topics mentioned in project announcements by Nara market in 2012 and 2013. The main contribution of our research can be found in the following aspects: i) the IT topic predictions announced by NIPA and NIA can provide an effective guideline to IT professionals and researchers in Korea who are looking for verified IT topic trends in the following topic, ii) researchers can use Twitter to get some useful ideas to detect and predict dynamic trends of technological and social issues.

• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.4
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• pp.126-138
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• 2017

Recently, the national interest in environment is increasing and for dealing with water environment-related issues swiftly and accurately, the demand to facilitate the analysis of water environment data using a GIS is growing. To meet such growing demands, a spatial network data-based stream network analysis map(Korean Reach File; KRF) supporting spatial analysis of water environment data was developed and is being provided. However, there is a difficulty in delineating catchment areas, which are the basis of supplying spatial data including relevant information frequently required by the users such as establishing remediation measures against water pollution accidents. Therefore, in this study, the development of a computer program was made. The development process included steps such as designing a delineation method, and developing an algorithm and modules. DEM(Digital Elevation Model) and FDR(Flow Direction) were used as the major data to automatically delineate catchment areas. The algorithm for the delineation of catchment areas was developed through three stages; catchment area grid extraction, boundary point extraction, and boundary line division. Also, an add-in catchment area delineation module, based on ArcGIS from ESRI, was developed in the consideration of productivity and utility of the program. Using the developed program, the catchment areas were delineated and they were compared to the catchment areas currently used by the government. The results showed that the catchment areas were delineated efficiently using the digital elevation data. Especially, in the regions with clear topographical slopes, they were delineated accurately and swiftly. Although in some regions with flat fields of paddles and downtowns or well-organized drainage facilities, the catchment areas were not segmented accurately, the program definitely reduce the processing time to delineate existing catchment areas. In the future, more efforts should be made to enhance current algorithm to facilitate the use of the higher precision of digital elevation data, and furthermore reducing the calculation time for processing large data volume.

• Journal of Intelligence and Information Systems
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• v.20 no.2
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• pp.109-122
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• 2014

People are nowadays creating a tremendous amount of data on Social Network Service (SNS). In particular, the incorporation of SNS into mobile devices has resulted in massive amounts of data generation, thereby greatly influencing society. This is an unmatched phenomenon in history, and now we live in the Age of Big Data. SNS Data is defined as a condition of Big Data where the amount of data (volume), data input and output speeds (velocity), and the variety of data types (variety) are satisfied. If someone intends to discover the trend of an issue in SNS Big Data, this information can be used as a new important source for the creation of new values because this information covers the whole of society. In this study, a Twitter Issue Tracking System (TITS) is designed and established to meet the needs of analyzing SNS Big Data. TITS extracts issues from Twitter texts and visualizes them on the web. The proposed system provides the following four functions: (1) Provide the topic keyword set that corresponds to daily ranking; (2) Visualize the daily time series graph of a topic for the duration of a month; (3) Provide the importance of a topic through a treemap based on the score system and frequency; (4) Visualize the daily time-series graph of keywords by searching the keyword; The present study analyzes the Big Data generated by SNS in real time. SNS Big Data analysis requires various natural language processing techniques, including the removal of stop words, and noun extraction for processing various unrefined forms of unstructured data. In addition, such analysis requires the latest big data technology to process rapidly a large amount of real-time data, such as the Hadoop distributed system or NoSQL, which is an alternative to relational database. We built TITS based on Hadoop to optimize the processing of big data because Hadoop is designed to scale up from single node computing to thousands of machines. Furthermore, we use MongoDB, which is classified as a NoSQL database. In addition, MongoDB is an open source platform, document-oriented database that provides high performance, high availability, and automatic scaling. Unlike existing relational database, there are no schema or tables with MongoDB, and its most important goal is that of data accessibility and data processing performance. In the Age of Big Data, the visualization of Big Data is more attractive to the Big Data community because it helps analysts to examine such data easily and clearly. Therefore, TITS uses the d3.js library as a visualization tool. This library is designed for the purpose of creating Data Driven Documents that bind document object model (DOM) and any data; the interaction between data is easy and useful for managing real-time data stream with smooth animation. In addition, TITS uses a bootstrap made of pre-configured plug-in style sheets and JavaScript libraries to build a web system. The TITS Graphical User Interface (GUI) is designed using these libraries, and it is capable of detecting issues on Twitter in an easy and intuitive manner. The proposed work demonstrates the superiority of our issue detection techniques by matching detected issues with corresponding online news articles. The contributions of the present study are threefold. First, we suggest an alternative approach to real-time big data analysis, which has become an extremely important issue. Second, we apply a topic modeling technique that is used in various research areas, including Library and Information Science (LIS). Based on this, we can confirm the utility of storytelling and time series analysis. Third, we develop a web-based system, and make the system available for the real-time discovery of topics. The present study conducted experiments with nearly 150 million tweets in Korea during March 2013.

• Journal of Broadcast Engineering
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• v.16 no.5
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• pp.750-761
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• 2011

Currently, 3DTV technologies are being developed as the future services of the HD digital broadcast environment. As one of the various research topics to apply 3DTV technologies to the conventional broadcasting network, methods to configure stereoscopic videos are being studied. In this paper, we proposed a method to broadcast high quality stereoscopic videos based on analysis of a method to add a stereoscopic descriptor to the PMT of MPEG-2 transport streams and a method to transmit stereoscopic videos by the expansion of MPEG-C part 3 which are from precedent studies. The proposed technique maintains compatibility with conventional MPEG-2 transport streams by showing only reference video for models that do not support 3D broadcasting. Therefore, the compatibility between conventional broadcasting and stereoscopic videos should make this method useful when activating 3D services in the communications and broadcasting area

• The Journal of Engineering Geology
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• v.21 no.1
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• pp.79-85
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• 2011

We investigated the flow properties of groundwater in areas of carbonate rocks at Yeongwol and Jeongseon, Gangwon Province, based on measurements of hydraulic conductivity. Existing hydraulic conductivity data were compiled from 46 wells in the study area. These wells were sunk close to Golji stream and the Joyang and Dong rivers, which flow through the study area. The hydraulic conductivities range from 0.004 to 1.1 m/day, and show a gradually decreasing trend with decreasing well depth (y=-0.003x - 0.927, $r^2$=0.129). The study area was classified into zone A (< 0.1 m/day), zone B (0.1-1.0 m/day), and zone C (> 1 m/day) according to hydraulic conductivity. Zones A, B, and C make up 87% (n = 40), 11 % (n = 5), and 2% (n = 2) of the surface of the study area, respectively. Among the three zones, zone A contains few fractures whereas zone C contains many fractures. These results indicate that groundwater flow in carbonate regions is strongly influenced by the fracture network.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.2
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• pp.103-112
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• 2011

This study aims to demonstrate the relationship between various factors and soil erosion or deposition, simulated from distributed rainfall-sediment-runoff model applications. We selected area, overland flow length, local slope as catchment representative characteristics among many important geographic factors and also used the grid-based accumulated rainfall as a representative hydro-climatic factor to assess the effect of these two different types of factors on erosion and deposition. The study catchment was divided based on the Strahler's stream order method for analysis of the relationship between area and erosion or deposition. Both erosion and deposition increased linearly as the catchment area became larger. Erosion occurred widely throughout the catchment, whereas deposition was observed at the grid-cells near the channel network with short overland flow lengths and mild slopes. In addition, the relationship results between grid-based accumulated rainfall and soil erosion or deposition showed that erosion increased gradually as rainfall amount increased, whereas deposition responded irregularly to variations in rainfall. Within the context of these results, it can be concluded that deposition is closely related with the geographic factors used in this study while erosion is significantly affected by rainfall.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.2B
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• pp.187-197
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• 2008

This study is to assess the impact of future land use change on hydrology and water quality in Gyungan-cheon watershed ($255.44km^2$) using SWAT (Soil and Water Assessment Tool) model. Using the 5 past Landsat TM (1987, 1991, 1996, 2004) and $ETM^+$ (2001) satellite images, time series of land use map were prepared, and the future land uses (2030, 2060, 2090) were predicted using CA-Markov technique. The 4 years streamflow and water quality data (SS, T-N, T-P) and DEM (Digital Elevation Model), stream network, and soil information (1:25,000) were prepared. The model was calibrated for 2 years (1999 and 2000), and verified for 2 years (2001 and 2002) with averaged Nash and Sutcliffe model efficiency of 0.59 for streamflow and determination coefficient of 0.88, 0.72, 0.68 for Sediment, T-N (Total Nitrogen), T-P (Total Phosphorous) respectively. The 2030, 2060 and 2090 future prediction based on 2004 values showed that the total runoff increased 1.4%, 2.0% and 2.7% for 0.6, 0.8 and 1.1 increase of watershed averaged CN value. For the future Sediment, T-N and T-P based on 2004 values, 51.4%, 5.0% and 11.7% increase in 2030, 70.5%, 8.5% and 16.7% increase in 2060, and 74.9%, 10.9% and 19.9% increase in 2090.

• Journal of Wetlands Research
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• v.18 no.4
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• pp.394-403
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• 2016

This study was carried out to verify change and relationship between the concentration of chlorophyll-a and environmental factors including weather, water quality and discharge at before & after Gangcheon and Ipoh weir construction at Namhan river, based on the weather and water quality data provided by the measuring network. We classified the period of before & after weir construction by the cluster analysis with Ward's method, and also through the correlation analysis between the concentration of chlorophyll-a and environmental factors, the influence factors related with algae occurrence(Chlorophyll-a) were analyzed. The result by cluster analysis based on data of the total 12 factors (water temperature, rainfall, daylight, pH, DO, BOD, COD, T-N, $NH_3-N$, $NO_3-N$, T-P, $PO_4-P$) from 2005 to 2015 indicated a clear classification into two periods, before(2006-2007) & after (2012-2013) weir construction. After weir construction, class of BOD at Gangcheon weir was better than before, changed from II class to Ia class, and likewise class of BOD at Ipoh weir was improved from II-III class to Ia-IIclass. Also T-P and T-N concentration also were to be improved in general after weir construction. Concentraion of Chlorophyll-a afterGangcheon and Ipoh weir construction was to be decreased. However, frequency of algae warning was increased from 9 to 15 after Ipoh weir construction due to increasing of HRT and water temperature. After weirs construction, the result of correlation analysis between weather, water quality and discharge and concentration of chlorophyll-a indicated a positive correlation, order of BOD(0.579) > COD(0.413) > temperature(0.237), and a negative correlation, order of $NO_3-N$(-0.344) > T-N(-0.293) at Gangcheon weir. And there were likewise positive correlation, order of BOD(0.795) > pH(0.581) > Water temperature(0.422), and negative correlation, order of $NO_3-N$(-0.457) > T-N(-0.371) > $NH_3-N$(-0.326) > $PO_4-P$(-0.288) > Discharge(-0.213) after Ipoh weir construction. Although water quality after Ipoh weir construction was generally improved, increase of frequency of algae warning occurrence was influenced by change of water conditions such as reduction of the velocity, increase of HRT and water temperature, etc impacted strongly by change of the stream flow more than change of water environments after weir construction.

• Korean Journal of Ecology and Environment
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• v.52 no.3
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• pp.245-265
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• 2019

Biotope, which represents the characteristic habitats of living organisms, need to be identified as essential for the efficient creation and sustainable management of urban ecosystems. This study was carried out to provide the basic information for ecological urban planning by analyzing types and attributes of the biotop established throughout the whole area of the Pohang city, a representative industrial city in Korea. The biotop established in Pohang city is composed of 12 types including forests (coniferous, deciduous, and mixed forests), agricultural fields (rice paddy and upland field), green facilities, river, reservoir, bare ground, residential area, public facilities, commercial area, industrial area, roads, and schools. As a result of analyzing the properties according to biotop types, industrial, commercial and residential areas, which represent urban areas, was dominated by introduced vegetation. Moreover the introduced vegetation is usually composed of exotic plants or modified forms for landscape architecture and horticulture rather than native plants, which reflects ecological property of both region and site. As the distance from the urban center increases, the agricultural field showed a form of typical farmland, whereas the closer it is, the more form of greenhouse farming. Natural green spaces were divided into riparian vegetation established along the stream and forest vegetation. Forest vegetation is consisted of secondary forests (seven communities) and plantations (three communities). The urban landscape of Pohang city is dominated by the industrial area. Among them, the steel industry, which occurs large amounts of heat pollution and carbon dioxide, occupies a large proportion. On the other hand, green space is very insufficient in quantity and inferior in quality. This study proposed several restoration plans and further, a green network, which ties the existing green spaces and the green space to be restored as a strategy to improve the environmental quality in this area.