• Korean Journal of Agricultural and Forest Meteorology
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• v.24 no.2
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• pp.83-94
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• 2022

In order to actively prepare to frost damage that occurs in the process of growing crops, the spatial and temporal distribution of frost occurrence in South Korea was derived using frost observation data from 20 regions over the past 21 years (2000~2020). The main products are the number of frost days, first frost day, and last frost day by region. And the climatic trends of these results were identified by performing the Mann-Kendall trend test and Sen's slope estimator. In South Korea, a lot of frost occurs in the inland area to the west of the Taebaek and Sobaek Mountains. Relatively closer to the coastal area, the number of frost days is small, the first frost day is slow, and the last frost day is early. The east coast region has fewer frost days, the first frost day is later, and the last frost day is earlier than the west coast region. The southern sea, the southeastern sea region, and the island region rarely experience frost. As a result of the annual time series trend analysis, although South Korea is a country where climate warming is progressing, there was no trend in reducing the number of frost days and slowing the first frost day, and it was found that the last frost day is delayed by 0.5 days per year.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.34 no.5
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• pp.144-155
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• 2022

The Korea Coast Guard evaluates the risk of major coastal activity places to prevent coastal accidents, and patrols and manages them based on that, but it is not responding properly to the continuously increasing number of coastal accidents. The reason for this is that, despite the gradual expansion of coastal activity places, there is a lack of manpower to manage and supervise them, resulting in blind spots in coastal accident safety management. Therefore, in order to solve this problem, it is necessary to prepare more efficient and effective measures that check and supplement the current coastal safety management system. Coastal accidents show different characteristics of accident causes and places due to differences in the activity characteristics of users according to time. As a result of analyzing coastal accident data (2017~2021), the frequency of daytime accidents is high in the case of sea rock, beach, and offshore, where family leisure activities are frequent. In the case of wharf, tidal flat and bridge, where accidents due to drinking, disorientation, and suicide mainly occur, the frequency of accidents at night is high. In addition, there were more accidents on weekends when the number of users increased compared to weekdays. This trend indicates that the user's temporal activity characteristics must be reflected in the risk assessment of coastal activity places. Therefore, in this study, based on the case of coastal accidents, the characteristics of accidents at coastal activity places according to time were identified, and the criteria were presented for risk evaluation by grading them. It is expected that it will be possible to lay the foundation for reducing coastal accidents by efficiently managing and supervising coastal activity places over time using the presented evaluation criteria.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.40 no.4
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• pp.275-292
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• 2022

In order to detect climate changes using satellite imagery, the GCOS (Global Climate Observing System) defines requirements such as spatio-temporal resolution, stability by the time change, and uncertainty. Due to limitation of GK-2A sensor performance, the level-2 products can not satisfy the requirement, especially for spatial resolution. In this paper, we found the optimal pan-sharpening algorithm for GK-2A products. The six pan-sharpening methods included in CS (Component Substitution), MRA (Multi-Resolution Analysis), VO (Variational Optimization), and DL (Deep Learning) were used. In the case of DL, the synthesis property based method was used to generate training dataset. The process of synthesis property is that pan-sharpening model is applied with Pan (Panchromatic) and MS (Multispectral) images with reduced spatial resolution, and fused image is compared with the original MS image. In the synthesis property based method, fused image with desire level for user can be produced only when the geometric characteristics between the PAN with reduced spatial resolution and MS image are similar. However, since the dissimilarity exists, RD (Random Down-sampling) was additionally used as a way to minimize it. Among the pan-sharpening methods, PSGAN was applied with RD (PSGAN_RD). The fused images are qualitatively and quantitatively validated with consistency property and the synthesis property. As validation result, the GSA algorithm performs well in the evaluation index representing spatial characteristics. In the case of spectral characteristics, the PSGAN_RD has the best accuracy with the original MS image. Therefore, in consideration of spatial and spectral characteristics of fused image, we found that PSGAN_RD is suitable for GK-2A products.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.1
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• pp.175-183
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• 2022

The collision between a ship and bridge across a waterway may result in extremely serious consequences that may endanger the safety of life and property. Therefore, factors affecting ship bridge collision must be investigated, and the impact force should be discussed based on various collision conditions. In this study, a finite element model of ship bridge collision is established, and the peak impact force of a ship bridge collision based on 50 operating conditions combined with three input parameters, i.e., ship loading condition, ship speed, and ship bridge collision angle, is calculated via numerical simulation. Using neural network models trained with the numerical simulation results, the prediction model of the peak impact force of ship bridge collision involving an extremely short calculation time on the order of milliseconds is established. The neural network models used in this study are the basic backpropagation neural network model and Elman neural network model, which can manage temporal information. The accuracy of the neural network models is verified using 10 test samples based on the operating conditions. Results of a verification test show that the Elman neural network model performs better than the backpropagation neural network model, with a mean relative error of 4.566% and relative errors of less than 5% in 8 among 10 test cases. The trained neural network can yield a reliable ship bridge collision force instantaneously only when the required parameters are specified and a nonlinear finite element solution process is not required. The proposed model can be used to predict whether a catastrophic collision will occur during ship navigation, and thus hence the safety of crew operating the ship.

• Journal of the Korean Society for Library and Information Science
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• v.56 no.3
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• pp.73-91
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• 2022

For everyone, books are not only a passage to break down temporal and spatial barriers, but also a passport to the world. However, books are neither a passage nor a passport for persons with print disabilities. They are suffering from a severe book famine, with only 1-7% of alternative materials in accessible formats. The Marrakesh Treaty is an international agreement promoted by the WBU and WIPO to reduce such access gaps and inequalities. Accordingly, this study intensively analyzed and linked the global book famine and the Marrakesh Treaty for the persons with print disabilities including the blind and visually impaired, and suggested strategic tasks and implementation plans to strengthen the services of the disabled in domestic libraries. The government and libraries should concentrate all their competencies on improving awareness, inducing standardization of alternative materials in the publishing industry, amending and supplementing the copyright act and related laws, strengthening the digital file collection and service of the National Library for the disabled, and developing and applying library guidelines to implement the Marrakesh Treaty. This is because if food supports the body of the disabled, reading fosters their spirit. In order to solve the global book famine for persons with print disabilities, it is necessary to improve the publishing industry's cartels, copyright holders' barricades, and the weak platform of the library industry. All copyright holders, publishers, and libraries should participate in reducing the 95% gap in access between non-disabled and disabled people. That is the mantra of the book famine.

• Journal of Korean Society on Water Environment
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• v.39 no.2
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• pp.162-174
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• 2023

In order to prevent water pollution caused by organic matter, Total Organic Carbon(TOC) has been adopted indicator and monitored. TOC can be divided into Dissolved Organic Carbon(DOC) and Particulate Organic Carbon(POC). POC is largely precipitated and removed during stream flow, which making DOC environmentally significant. However, there are lack of studies to define spatio-temporal distributions of DOC in stream affected by various land use. Therefore, it is necessary to estimate the past DOC concentration using other water quality indicators to evaluate status of watershed management. In this study, DOC was estimated by correlation and regression analysis using three different organic matter indicators monitored in mixed land-use watersheds. The results of correlation analysis showed that DOC has the highest correlation with TOC. Based on the results of the correlation analysis, the single- and multiple-regression models were developed using Biochemical Oxygen Demand(BOD), Chemical Oxygen Demand(COD), and TOC. The results of the prediction accuracy for three different regression models showed that the single-regression model with TOC was better than those of the other multiple-regression models. The trend analysis using extended average concentration DOC data shows that DOC tends to decrease reflecting watershed management. This study could contribute to assessment and management of organic water pollution in mixed land-use watershed by suggesting methods for assessment of unmeasured DOC concentration.

• Journal of the Daesoon Academy of Sciences
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• v.26
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• pp.215-253
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• 2016

In 2007, according to the records, I made an on-the-spot survey of the place where Doju Cho Jeongsan and his family might have lived in exile in Manchuria and released a paper in which I decided that the site could be the Shuidongchun (village) of Luotongshanzhen in Liuhexian, Jilin Province. Thereafter, sponsored by the Doju Cho Jeongsan's Memorial Project from 2008 to 2013, many times, I carried out the field investigations and researches on Liuhexian, including the visits of the institutions which have the historical documents, in order to find the data related to the participation of him and his family in the anti-Japanese movement. I was, hence, able to reconfirm that the village had been the place of their exile, based on my collected data and the oral reports which the local historians and ethnic Korean elders had provided. In this study, using the historical documents and maps and the oral materials, I made an attempt to prove the historical truth thoroughly once again. First, the existing sources of Doju Cho and his family's settling in Manchuria from March 1909 to 1917, were carefully analyzed which were described in The Jin-gyeong. In doing so, the misspelling of the names and the spatio-temporal errors of the people's activities were corrected. Next, I researched on another town, Shuitungou of Liuhexian in Fengtian Province (in West Gando of Manchuria), which it is known that Doju and his family stayed in, and the Laogushan (mountain), which it is believed that Doju cultivated himself in. Finally, through the attempt, I reached the conclusion that Doju and his family had settled at Shuidongchun (once called Shuidonggou or Shuitongchun) of Luotongshanzhen (once called Datonggou) in Liuhexian, Jilin Province. In the Liuhexian-related documents and maps published in the eras of Republican China and Manchuria, the place name called Shuitungou was not found. However, I discovered a map in the era of Republican China on which Shuitongchun was recorded as Shuidonggou. In addition, considering the administration system of Republic China, tun(屯) and gou(溝) could not be used together in the place names. Accordingly, Shuitungou was more likely misspelled as Korean people in those days mispronounced Shuidonggou. Furthermore, people in China has habitually called the Dagushan(大孤山), located in the north of Gushanzizhen of Liuhexian, as the Laogushan(老孤山). This means that the Korean people who lived in the area then perhaps recorded the mountain as the Nogosan(老姑山), the mountain of the old goddess, according to Korean enunciation, because they had the custom of worshipping the mountain goddess. I tried my best to find the historical documents regarding Doju and his family's anti-Japanese activities to prove the location of exile in which they settled in northeastern China (Manchuria). However, I was not able to reach the initial goal completely due to the shortage of objective evidences, only to leave tasks to be solved. I hope that this study can give a little help to researchers who are interested in this matter.

• Korean Journal of Social Welfare
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• v.69 no.4
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• pp.41-65
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• 2017

This study aimed to examine the social transition, which is often metaphorized as the Fourth Industrial Revolution, within the context of social work practice and to explore measures to improve social work practice in such transition. Four social welfare researchers held seven discussions to predict the social changes in the near future centered on the Fourth Industrial Revolution and find the corresponding development strategies in social work practice; collective autobiography method was used to analyze the discussion. The analysis ascertained hyper connectivity, the advent and expansion of new communities, diversification and individualization, and the emergence of new criteria for the assessment of one's quality of life as the distinctive qualities of the near future. It was analyzed that humans and organic materials will be interconnected through spatial and temporal transcendence and that humans liberated from labor will seek for diverse communities while the number of atomized individual will increase simultaneously. Furthermore, the rise of new order of life accompanied by both the expansion of diversification and individualization and the ecological worldview brought forth by post materialistic trend was predicted. Meanwhile, the disengagement from macroscopic context, a biased inclination towards technique orientated professionalism, and individualistic social work practices without integrity were identified as the limitations of the current social work practice. This study presented three goals for social work practice to help it overcome its current shortcomings and correspond to the social changes: first, the rearrangement of practice knowledge, technique, and value so that it is based on humans and society, which are the essence of social practice work; second, the practice, such as sharing economy, that expands the individuals' boundaries of life to the community; three, the restoration of the desirability of professional social works by examining its special nature.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1B
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• pp.61-67
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• 2006

Various methods have been applied for the research to model the relationship between rainfall-runoff, which shows a strong nonlinearity. In particular, most researches to model the relationship between rainfall-runoff using artificial neural networks have used back propagation algorithm (BPA), Levenberg Marquardt (LV) and radial basis function (RBF). and They have been proved to be superior in representing the relationship between input and output showing strong nonlinearity and to be highly adaptable to rapid or significant changes in data. The theory of artificial neural networks is utilized not only for prediction but also for classifying the patterns of data and analyzing the characteristics of the patterns. Thus, the present study applied self?organizing map (SOM) based on Kohonen's network theory in order to classify the patterns of rainfall-runoff process and analyze the patterns. The results from the method proposed in the present study revealed that the method could classify the patterns of rainfall in consideration of irregular changes of temporal and spatial distribution of rainfall. In addition, according to the results from the analysis the patterns between rainfall-runoff, seven patterns of rainfall-runoff relationship with strong nonlinearity were identified by SOM.

• Korean Journal of Social Welfare Studies
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• v.41 no.3
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• pp.135-162
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• 2010

The Purpose of this study is to get basic material about voluntary association in local community and its utilization. In order to achieve the purpose of this study, it was considered that trust of social capital plays a leading part in voluntary association to maintain or strengthen its role and activities. For this reason we attempt to find the process of trust building in voluntary association. The revised ground theory that is complementary weaknesses of ground theory is used in this study and in 11months, four times researches have investigated. As a result, it was analyzed that the structure of building trust can be categorized into three structure, building up relationship, dynamic interaction and structural stabilization in voluntary association. In the space that is structured spatially and temporal, role, activity, accomplishment, attitude, conflict and environment acted as basic attributes. These attributes can be found in every building process of trust and influence on continuance and growth of voluntary association. The fact that this study offers in-depth understanding of voluntary association and empirical directivity regarding the community welfare services is of great significant.