• Journal of People, Plants, and Environment
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• v.24 no.1
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• pp.39-51
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• 2021

Background and objective: Urban topology can be characterized as impervious, which changes the hydrologic features of an area, increasing surface water flow during local heavy rain events. The pluvial flooding is also influenced by the vertical structures of the urban area. This study suggested a modified digital elevation model (DEM) to identify changes in urban hydrological conditions and segmentalized urban micro catchment areas using a geographical information system (GIS). Methods: This study suggests using a modified DEM creation process based on Rolling Ball Method concepts along with a GIS program. This method proposes adding realized urban vertical data to normal DEM data and simulating hydrological analyses based on RBM concepts. The most important aspect is the combination of the DEM with polygon data, which includes urban vertical data in three datasets: the contour polyline, the locations of buildings and roads, and the elevation point data from the DEM. DEM without vertical data (DCA) were compared with the DEM including vertical data (VCA) to analyze catchment areas in Shin-wol district, Seoul, Korea. Results: The DCA had 136 catchments, and the area of each catchment ranged from 3,406 m² to 423,449 m². The VCA had 2,963 catchments, with the area of each ranging from 50 m² to 16,209 m². The most important finding is that in the overlapped VCA; the boundary of areas directly affected by flooding and the direction of surface water flow could be identified. Flooding data from September 21, 2010 and July 27, 2011 in the Shin-wol district were applied as ground reference data. The finding is that in the overlapped VCA; the boundary of areas directly affected by flooding and the direction of surface water flow could be identified. Conclusion: The analysis of the area vulnerable to surface water flooding (SWF) was more accurately determined using the VCA than using the DCA.

• KNOM Review
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• v.23 no.2
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• pp.1-10
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• 2020

Network Function Virtualization (NFV) is a key technology of 5G networks that has the advantage of enabling building and operating networks flexibly. However, NFV can complicate network management because it creates numerous virtual resources that should be managed. In NFV environments, service function chaining (SFC) composed of virtual network functions (VNFs) is widely used to apply a series of network functions to traffic. Therefore, it is required to dynamically allocate the right amount of computing resources or instances to SFC for meeting service requirements. In this paper, we propose Deep Q-Networks (DQN)-based auto-scaling to operate the appropriate number of VNF instances in SFC. The proposed approach not only resizes the number of VNF instances in SFC composed of multi-tier architecture but also selects a tier to be scaled in response to dynamic traffic forwarding through SFC.

• KIPS Transactions on Software and Data Engineering
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• v.12 no.9
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• pp.399-406
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• 2023

Cloud computing has been evolved to support edge computing architecture that combines fog management layer with edge servers. The main reason why it is received much attention is low communication latency for real-time IoT applications. At the same time, various cloud task scheduling techniques based on artificial intelligence have been proposed. Artificial intelligence-based cloud task scheduling techniques show better performance in comparison to existing methods, but it has relatively high scheduling time. In this paper, we propose a deep learning-based dynamic scheduling with multi-agents supporting scalability in edge computing environments. The proposed method shows low scheduling time than previous artificial intelligence-based scheduling techniques. To show the effectiveness of the proposed method, we compare the performance between previous and proposed methods in a scalable experimental environment. The results show that our method supports real-time IoT applications with low scheduling time, and shows better performance in terms of the number of completed cloud tasks in a scalable experimental environment.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.136-136
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• 2021

In this study, a deep convolutional neural network (DCNN) model is proposed for short-term precipitation forecasting using weather radar-based images. The DCNN model is a combination of convolutional neural networks, autoencoder neural networks, and U-net architecture. The weather radar-based image data used here are retrieved from competition for rainfall forecasting in Korea (AI Contest for Rainfall Prediction of Hydroelectric Dam Using Public Data), organized by Dacon under the sponsorship of the Korean Water Resources Association in October 2020. This data is collected from rainy events during the rainy season (April - October) from 2010 to 2017. These images have undergone a preprocessing step to convert from weather radar data to grayscale image data before they are exploited for the competition. Accordingly, each of these gray images covers a spatial dimension of 120×120 pixels and has a corresponding temporal resolution of 10 minutes. Here, each pixel corresponds to a grid of size 4km×4km. The DCNN model is designed in this study to provide 10-minute predictive images in advance. Then, precipitation information can be obtained from these forecast images through empirical conversion formulas. Model performance is assessed by comparing the Score index, which is defined based on the ratio of MAE (mean absolute error) to CSI (critical success index) values. The competition results have demonstrated the impressive performance of the DCNN model, where the Score value is 0.530 compared to the best value from the competition of 0.500, ranking 16^th out of 463 participating teams. This study's findings exhibit the potential of applying the DCNN model to short-term rainfall prediction using weather radar-based images. As a result, this model can be applied to other areas with different spatiotemporal resolutions.

• Korean Journal of Environment and Ecology
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• v.33 no.5
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• pp.506-514
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• 2019

Unlike natural ecosystems, the urban ecosystem proVides an interdependent enVironment in which wild organisms and urban people co-exist. Hornets (genus Vespa) appearing in urban green and parks haVe a positiVe effect on urban ecosystems, but they also cause ecosystem disserVices that cause physical and psychological discomforts to the urban people. Children's parks, for example, are Very popular among children and residents for easy accessibility, and hornets also use them as bases and habitats. HoweVer, there is still a lack of spatial analysis of habitats and appearance characteristics of hornets in children's parks. This study installed hornet traps in 27 children's parks in Cheonan from April to NoVember 2018 in consideration of the life cycle of hornets. We captured a total of fiVe Vespa species (Vespa crabro, V. analis, V. mandarinia, V. ducalis, and V. Velutina) for 32 weeks and analyzed the emergence of hornets in relation to the composition of seasonal characteristics, species characteristics, and enVironmental spatial information. We captured a total of 818 hornets during the study period. They included 290 V. analis (35.4%), 260 V. crabro (31.8%), 100 V. ducalis (12.1%), 87 V. mandaninia (10.6%), and 81 V. Velutina(9.9%). Most of the hornets showed a common feature that queen hornets were largely captured in May through June after they awake from hibernation, and the number of caught hornets decreased sharply beginning in mid-June, which was the cooperatiVe period. HoweVer, V. Velutina showed a seasonal specificity that more than 80% were captured beginning in the third week of October when other hornet species had already entered a decline phase. The analysis of the number of hornets caught in each spot in children's parks showed significant difference among the spots as 363 hornets (44.3%) were captured in top children's parks, and 35 hornets (4%) were captured in bottom children's parks. In particular, the mean NDVI (Normalized difference Vegetation index) of the top six children's parks was 0.79, and that of the bottom six children's parks was 0.38 (t=2.67*, *=p<0.05), indicating a significant difference. The frequency of capturing hornets was high when the ground around the children's parks was grass or bare land. This study is meaningful as a reference study that confirms the ecological characteristics of hornets appearing in green and parks in the city. We expect it to be a foundation for effectiVe urban green area management in the future.

• Journal of the Korean Institute of Landscape Architecture
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• v.49 no.4
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• pp.15-29
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• 2021

The study aims to grasp the perception and appraisal of urban park users through text analysis. This study used Google review data provided by Google Maps. Google Maps Review is an online review platform that provides information evaluating locations through social media and provides an understanding of locations from the perspective of general reviewers and regional guides who are registered as members of Google Maps. The study determined if the Google Maps Reviews were useful for extracting meaningful information about the user perceptions and appraisals for parks management plans. The study chose three urban parks in Seoul, South Korea; Seoul Forest, Boramae Park, and Olympic Park. Review data for each of these three parks were collected via web crawling using Python. Through text analysis, the keywords and network structure characteristics for each park were analyzed. The text was analyzed, as were park ratings, and the analysis compared the reviews of residents and foreign tourists. The common keywords found in the review comments for the three parks were "walking", "bicycle", "rest" and "picnic" for activities, "family", "child" and "dogs" for accompanying types, and "playground" and "walking trail" for park facilities. Looking at the characteristics of each park, Seoul Forest shows many outdoor activities based on nature, while the lack of parking spaces and congestion on weekends negatively impacted users. Boramae Park has the appearance of a city park, with various facilities providing numerous activities, but reviewers often cited the park's complexity and the negative aspects in terms of dog walking groups. At Olympic Park, large-scale complex facilities and cultural events were frequently mentioned, emphasizing its entertainment functions. Google Maps Review can function as useful data to identify parks' overall users' experiences and general feelings. Compared to data from other social media sites, Google Maps Review's data provides ratings and understanding factors, including user satisfaction and dissatisfaction.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.41 no.3
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• pp.47-58
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• 2023

This study was conducted through reviewing Aspects of Design and Construction in Entrance Space of the World Heritage Royal Tombs of the Joseon Dynasty, which is equipped with parking lots, ticket offices, toilets, exhibition halls, information boards, and rest facilities for the convenience of visitors and the purpose of this study was to propose a direction for improvement. The results of the study are as follows: First, the reduced area of Royal Tombs of the Joseon Dynasty was unable to fully accommodate the ritual movement line, and as a result, the location of the entrance space in the current royal tomb was decided to accommodate minimal convenience functions. In the meantime, the entrance space of the royal tombs has been relocated or renovated in order to achieve its integrity as a World Heritage Site, rational arrangement of movement lines and spatial utility. Second, the size of the entrance space ranges from 1,000 square meters in Jeongneung in Seoul to 16,000 square meters in Hongyuneung in Namyangju, and the number of annual users varies greatly from 12,000 in Onneung in Yangju to 410,000 in Seonjeongneung in Seoul. Considering the conditions of the 16 royal tombs, the entrance space should be provided at an appropriate scale, reflecting the surrounding land use and accessibility that affect the influx of users, the size of the site, and the king's awareness and preferences. Third, the location of the parking lot, the presence or absence of an outer courtyard and an internal courtyard bordering the ticket and check offices, and the location of the Historical and Cultural Museum made it possible to know the aspects of entrance space of the Joseon Royal Tombs, where the spatial configuration is determined Fourth, according to the royal tombs, it was found that the entrance space should have essential parking, access control, information, and convenience functions, and that support, exhibition, passage, and recess functions should be optional. At this time, the management office and the Historical and Cultural Center are in charge of support and exhibition functions. The function of passage can be a strategy that provides a sense of entry and the function of recess which has been introduced in only four royal tombs requires an appropriate location and landscape access.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.2
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• pp.41-53
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• 2010

Traffic safety assessment is often accomplished by analyzing the number of crashes occurring in some geographic space over certain specific time duration. In this paper, we introduce a procedure that can efficiently analyze spatial and temporal changes in traffic crashes before-and-after implementation of a certain traffic controlling measure. For the analysis, crash frequency data before-and-after closing a major highway around St. Louis in Missouri was collected through Transportation Management System(TMS) database that is maintained by Missouri Department of Transportation (MoDOT). In order to identify any spatial and temporal pattern in crashes, each crash is pinpointed on a map using the dynamic segmentation in GIS. Then, the identified pattern is statistically confirmed using an analysis of variance table. The advantage of this approach is to easily assess spatial and temporal trend of crashes that are not readily attainable otherwise. The results from this study can possibly be applied in enhancing the highway safety assessment procedure. This paper also makes several suggestions for future development of a comprehensive transportation data system in Korea which is similar to MoDOT's TMS database.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.12
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• pp.7430-7437
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• 2014

Owing to the increase in large and complex construction projects, the design paradigm of architecture and civil engineering projects has changed from 2D CAD to 3D CAD. For this reason, to meet the strong requirements of project contractors, various efforts have been made to adopt a Building Information Modeling (BIM) technology for effective construction management. On the other hand, compared to architectural projects, only a few civil engineering project cases have been conducted in the perspective of public contractors. This is because the characteristics of civil project contractors and the negative pursuit of adopting BIM technology due to the lack of a current BIM system and technologies. Recently, positive changes in adopting BIM technology for public projects were anticipated by public owners, such as the Public Procurement Service and the Ministry of Land, Infrastructure and Transport. In this regard, this study analyzed the current BIM technology status of public owners in Korea to adopt the BIM policies and guidelines of the Korean government. Strategies for adopting BIM technologies for Korean public owners are also discussed based on an analysis of civil engineering BIM project cases.

• Information Systems Review
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• v.14 no.3
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• pp.115-129
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• 2012

A matchmaking system is a type of recommender systems that provides a set of dating partners suitable for the user by online. Many matchmaking systems, which are widely used these days, require users to specify their preferences with regards to ideal dating partners based on criteria such as age, job and salary. However, some users are not aware of their exact preferences, or are reluctant to reveal this information even if they do know. Also, users' selection standards are not fixed and can change according to circumstances. This paper suggests a new matchmaking system called Decision Tree based Matchmaking System (DTMS) that automatically adjusts the stated standards of a user by analyzing the characteristics of the people the user chose to contact. AMMS provides recommendations for new users on the basis of their explicit preferences. However, as a user's behavioral records are accumulated, it begins to analyze their hidden implicit preferences using a decision tree technique. Subsequently, DTMS reflects these implicit preferences in proportion to their predictive accuracy. The DTMS is regularly updated when a user's data size increases by a set amount. This paper suggests an architecture for the DTMS and presents the results of the implementation of a prototype.