• Convergence Security Journal
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• v.17 no.5
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• pp.41-47
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• 2017

The Marine Environment Observation Information System supplies oceanographic information elements such as water temperature, chlorophyll, float, etc. based on satellite images to consumers. The data produced by the Korean marine environmental observatories are located in the coastal areas of Korea. But if the range is too far from a particular area of interest, due to distance or spatial constraints, the accuracy and up-to-dateness of the data can not be relied upon. Therefore, it is necessary to perform fusion and complex operation to solve the difference between the field observation and the marine satellite image. In this study, we develop a system that can process marine environmental information in the user's area of interest in the form of layered character (numeric) information considering the readability and light weight rather than the satellite image. In order to intuitively understand satellite image information, we characterize (quantify) the marine environmental information of the area of interest and we process the satellite image band values into layered characters to minimize the absolute amount of transmitted / received data. Also we study modular location-based interest information service method to be able to flexibly extend and connect interested items that diversify various observation fields as well as application technology to serve this.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.55 no.2
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• pp.121-128
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• 2019

Various artificial reefs provide the fish habitat and nursery, and contribute the improvement of fisheries productivity. The evaluation methods of fishery resources in the artificial reefs have been done by fishing, scuba diving, underwater camera, and scientific echo sounder/sonar. There are a number of studies using echosounders on the quantitative and qualitative evaluations of artificial reefs in various seas around the world. This study focused on the spatial distribution of fishes around artificial reefs and the influential area of reefs off Bukchon, Jeju Island. Not only acoustic data but also various properties of artificial reefs were used in the geographic information system to extract relevant results. As a result, the major material of reefs on this study site was concrete and the number of reefs with that material was the most. The volume of reefs consisted of steel only and steel with riprap was considerably large compared to other reefs. The average NASC in the vertical distribution of fishes in artificial reefs was $31.6m^2/nm^2$ in April, and that was $61.3m^2/nm^2$ in June. The distance between the fish school and their nearest reef in June morning had a wide range from 750 to 3250 m. On the basis of the influence ray of artificial reefs, it had a tendancy of NASC to decrease with distance from the reef in the June morning. It is a preliminary study to present the geospatial analysis example to understand a better way of comprehensive artificial reef environments.

• Informatization Policy
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• v.26 no.1
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• pp.62-82
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• 2019

This study attempts to make an empirical analysis on how mobile devices affect users in building their social relationship and if their influences are negative or positive. The purpose of this research is to explain the results by considering all the possibilities and exploring everyday lives of using mobile devices. We used the survey data from the "Research on Mobile Environment Awareness" conducted by Gyeonggi Research Institute(GRI). The main question was about the use of mobile devices and social network services (SNS) and users' opinions on using the devices. All of the 31 municipalities in Gyeonggi Province were included as a spatial range, and the final validity sample was 1,004 residents. The extent of the relationship with people is selected as a dependent variable through the multinomial logistic model and the decision tree model. As a result of the multinomial logistic analysis on the questionnaire, the characteristics of the respondents with some changes in the scope of the human relationship were found to have a significant (+) effect on conversation with family, SNS usage, residence in the rural area but not urban area, and device usage for obtaining news. The largest variable affecting the extent of relationship was the SNS usage. As the amount of SNS usage increases, the extent of the relationship also changes a lot.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.30 no.6
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• pp.286-297
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• 2018

In the present study, wave measurements at KOGA-W01 were analyzed and then the numerical wind waves simulations have been conducted to investigate the characteristics of wind waves in the Yellow sea. According to the present analysis, even though the location of the wave stations are close to the coastal region, the deep water waves are prevailed due to the short fetch length. Chun and Ahn's (2017a, b) numerical model has been extended to the Yellow Sea in this study. The effects of tide and tidal currents should be included in the model to accommodate the distinctive effect of large tidal range and tidal current in the Yellow Sea. The wave hindcasting results were compared with the wave measurements collected KOGA-W01 and Kyeockpo. The comparison shows the reasonable agreements between wave hindcastings and measured data, however the model significantly underestimate the wave period of swell waves from the south due to the narrow computational domain. Despite the poorly prediction in the significant wave period of swell waves which usually have small wave heights, the estimation of the extreme wave height and corresponding wave period shows good agreement with the measurement data.

• Journal of the Korean GEO-environmental Society
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• v.20 no.1
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• pp.5-11
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• 2019

The main objective of this study was to analyse polycyclic aromatic hydrocarbons in surface sediments obtained from near Nakdong estuary, and to estimate ecological risks of PAHs using PAHs concentrations. The main constituents of sediments were $SiO_2$, $Al_2O_3$, CaO, $Fe_2O_3$, and ignition loss of sediments ranged from 2.97% and 8.39%. Total concentrations of PAHs ranged from $128.4ng\;g^{-1}$ and $507.4ng\;g^{-1}$, and the major PAHs were 2 ring and 4 ring aromatic hydrocarbons. Each concentrations of PAHs are all below effect range low, which indicated that each PAHs in 8 studying sites show low ecological risk. From M-ERM-Q analyses, M-ERM-Q values of 8 studying sites are below 0.1 indicating low ecological risk. From source apportionment analyses, PAHs come from grass, wood, charcoal combustion for N-1 and N-7, petroleum combustion for N-5 and N-6, petroleum pollution for N-2, N-3, N-4, N-8.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.363-373
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• 2018

In today's diversified society, it is hard to know which building style represents the architectural style of the time. The simplicity found in monolithic-style buildings forms a symmetrical point with fairly complex structure, and its value can be acknowledged. This study analyzes buildings made of insulating lightweight aggregate concrete in the early 21st century, defines the concept of monolithic expression, and examines how these characteristics are expressed in the space, forms, and structural methods in construction. Unlike a multi-layered exterior wall system, which features multiple layers composed of a variety of materials, the exterior walls built with insulating lightweight aggregate concrete comes in a lump form with a mold form that is tightly filled with concrete as a single material and is monolithic. This is attributed to the creation of spaces characterized by the homogeneity of inner and outer spaces with the use of the same material, continuity of the surface as solidity, spatial characteristics of the stereotomic construction, expression of materiality with the use of exposed concrete, and the contrast of the lump and the space. This not only reveals formal characteristics that expose a discourse about monolithic architecture in contemporary architecture but also provide an opportunity to extend the range of discussion to structures and materials and even to their effects on space.

• Korean Journal of Heritage: History & Science
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• v.54 no.3
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• pp.204-227
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• 2021

This paper proposed the validity and necessity of establishing the Jungwon Historical and Cultural Area by reviewing the historical characteristics of the name Jungwon and its temporal and spatial range. We also explored ways to utilize the Jungwon historical and cultural Area under the Special Act on the Maintenance of Historical and Cultural Areas. Jungwon, which means the center of the country, has strategic value as a key area connecting the Korean Peninsula to the north and south through the Geripryeong and Jukryeong. It also includes Chungju, which connects the Namhan and Bukhan Rivers . From the Mahan period, the areas of Cheongju and Jincheon, the Miho Stream basin to the west, and Chungju to the east were closely connected to each other. Afterwards, Baekje, Koguryo, and Silla engaged in a fierce battle to occupy the Jungwon area. Jungwon culture was born through the negotiation and fusion of the cultures of the three kingdoms. In particular, Silla continued to value the Jungwon area, demonstrated by the installation of Seowongyeong in Cheongju and Bukwongyeong in Wonju, centering on the Jungwongyeong. Since we have a historical view with a focus on ancient kingdoms, we have overlooked the full value of the history and culture of Jungwon. We need to recognize the importance of Jungwon area and think about how to utilize it. Therefore, we suggested in this paper that there be more public information services on the cultural heritage of Jungwon, the historical heritage experience, and the education programs for local residents. The development and operation of Jungwon's history, culture, and tourism contents, as well as the various academic research papers should be used to reveal the identity of the Jungwon historical and cultural area.

• Journal of Korea Water Resources Association
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• v.54 no.5
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• pp.301-309
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• 2021

In this study, we tried to improve the performance of the existing U-net-based deep learning rainfall prediction model, which can weaken the meaning of time series order. For this, ConvLSTM2D U-Net structure model considering temporal consistency of data was applied, and we evaluated accuracy of the ConvLSTM2D U-Net model using a RainNet model and an extrapolation-based advection model. In addition, we tried to improve the uncertainty in the model training process by performing learning not only with a single model but also with 10 ensemble models. The trained neural network rainfall prediction model was optimized to generate 10-minute advance prediction data using four consecutive data of the past 30 minutes from the present. The results of deep learning rainfall prediction models are difficult to identify schematically distinct differences, but with ConvLSTM2D U-Net, the magnitude of the prediction error is the smallest and the location of rainfall is relatively accurate. In particular, the ensemble ConvLSTM2D U-Net showed high CSI, low MAE, and a narrow error range, and predicted rainfall more accurately and stable prediction performance than other models. However, the prediction performance for a specific point was very low compared to the prediction performance for the entire area, and the deep learning rainfall prediction model also had limitations. Through this study, it was confirmed that the ConvLSTM2D U-Net neural network structure to account for the change of time could increase the prediction accuracy, but there is still a limitation of the convolution deep neural network model due to spatial smoothing in the strong rainfall region or detailed rainfall prediction.

• Journal of Convergence for Information Technology
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• v.11 no.1
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• pp.136-142
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• 2021

Open-pit mine development requires continuous management because of topographical changes and there is a risk of accidents if the current status survey is performed directly in the process of calculating the earthwork. In this study, the application of UAV photogrammetry, which can acquire spatial information without direct human access, was applied to open-pit mines development area and analyzed the accuracy, earthwork, and mountain restoration plan to determine its applicability. As a result of accuracy analysis at checkpoint using ortho image and Digital Surface Model(DSM) by UAV photogrammetry, Root Mean Square Error(RMSE) is 0.120 m in horizontal and 0.150 m in vertical coordinates. This satisfied the tolerance range of 1:1,000 digital map. As a result of the comparison of the earthwork, UAV photogrammetry yielded 11.7% more earthwork than the conventional survey method. It is because UAV photogrammetry shows more detailed topography. And result of monitoring mountain restoration showed possible to determine existence of rockfall prevention nets and vegetation. If the terrain changes are monitored by acquiring images periodically, the utility of UAV photogrammetry will be further useful to open-pit mine development.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.6
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• pp.1201-1208
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• 2020

A mass of seawater with similar properties in the ocean is called a water mass, and the front is a sea area where two masses of different properties meet. The gradient algorithm is a method of extracting where the sea water temperature pixel changes rapidly assuming that the slope is large, and the place with the large slope is assumed to be a front. This method is able to process large amounts of satellite data at once. Therefore, in this study, we tried to find the front lines in the sea area around the Korean Peninsula by using a gradient algorithm. The study data used gridded sea surface temperature satellite data. The resolution was 1/4°, and the monthly average data from January 1993 to December 2018 were used. There were major five fronts representatively, China Coastal Front, South Sea Coastal Front, Kuroshio Front/ Kuroshio Extension Front, Subpolar Front and the Subarctic Front. As a result of comparing the distribution of front by season, more types of front were distributed in winter and spring than in summer and autumn, and the distribution range was wider.