• Journal of the Korean Geotechnical Society
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• v.35 no.7
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• pp.15-27
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• 2019

The purpose of this study is to investigate the mechanism about damages occurring at quay wall and backfill in Youngilman Port during Pohang earthquake (M5.4) on November 15, 2017. In the field investigation, the horizontal displacement of the caisson occurred between 5 cm and 15 cm, and the settlement at backfill occurred higher than 10 cm. 2D-effective Stress Analysis was performed to clarify the mechanism for the damage. The input earthquake motion used acceleration ($3.25m/s^2$) measured at bedrock of Pohang habor. Based on a numerical analysis, it was found that the effective stress decreased due to the increase of excess pore pressure in the backfill ground and the horizontal displacement of the caisson occurred by about 14 cm, and the settlement occurred by about 3 cm. In backfill, the settlements occurred between 6 cm and 9 cm. This is similar to field investigation results. Also, it was found that the backfill soil was close to the Mohr-Coulomb failure line due to the cyclic loading from the effective stress path and the stress-strain behavior. It may be related to decreasing of bearing capacity induced by the reduction of effective stress caused by the increase of the excess pore water pressure.

• Journal of Korean Society of Disaster and Security
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• v.13 no.4
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• pp.1-12
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• 2020

Recently, as the extreme drought continued due to the reckless development and the dramatical climate change, national concern about the water management issues has been increased rapidly around the world, especially in Korea. Meanwhile, it is necessary to analyze and review the related cases in Australia, where they have developed the consistently, eco-friendly and systematically management from the national level, which is similar to that of Korea in difficult circumstances. Australia has been suffered by repeated droughts and floods due to low rainfall and dryness, and water disputes were begun with immigrant settlement in the 1890s. In the early days, water management agreements for efficient distribution of water resources, water use regulation programs, and federal water laws were enacted, and now the established water management system in which development and conservation are assumed to be well balanced. In Korea, however, in the past, the Ministry of Environment was responsible for water quality issues while the quantity was managed by the Ministry of Land, Infrastructure and Transport, and the main local departments for water management were divided. Therefore, it was difficult to manage the integrated water management due to problems such as duplicated works, excessive investments, and inefficiency. To resolve this situation, in 2018, all water management functions were unified, such as enacting the fundamental water-related laws, thereby laying the foundation for the integrated water management system for each basin. From 2019, even the integrated water management system was implemented, we are promoting the effect of sustainable water resource management. In order to establish a management policy for efficient and eco-friendly water management, the IWRM (Integrated Water Resource Management) of Australia, which has been devised in various ways, was analyzed and compared with the present situations and cases occurred in Korea, and the implications from this study would be suggested the future of IWRM in Korea.

• Journal of Internet Computing and Services
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• v.22 no.4
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• pp.123-134
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• 2021

This paper suggests that the Internet is not free through analysis of U.S. Internet history and lawsuits related to the Charter merger in 2016. Generally speaking, the players in internet connectivity market agree to Non-Disclosure Agreement, when connecting their facilities and networks each other. So, I adopted the case study & analysis as research methodologies due to limitation of collecting the transaction data between them. The former finds that Internet access has never been free in U.S Internet history. As we know, some including Content Providers(CPs) argue that the Internet is a free network and there are many cases to use the internet for free, so they came to conclusion that ISPs have no right to charge the users like CPs. This study refutes these arguments in two ways. One is that using the internet has never been free. From ARPANET, known as the beginning of the U.S. Internet, to the commercialization of backbone, no Internet has been considered or implemented for free since the early Internet network was devised. Also, the U.S government was paying subsidies or institutions were paying fees to secure network operations for the NSFNET backbone. the other is that "free peering" refers to barter transactions between ISPs, not to free access to counterpart internet networks. Second, this study analyze the FCC' executive order of conditioned merger approval and the court's related ruling and verify that using the internet is not free. According to the analysis, this study finds that it's real situation to make paid settlements between ISP-CPs (including OTTs) in the US Internet market at the moment. This study concludes that the Internet has never been free in terms of its technical characteristics, network structure, network operation, and system. Also it proposes how to improve the domestic settlement system between ISPs-CPs in terms of policy and regulation.

• Journal of Cadastre & Land InformatiX
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• v.50 no.2
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• pp.237-254
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• 2020

Housing vacancies have become a major issue in urban areas, there have been many efforts to address this issue at the national and local levels. The purpose of this paper is to investigate the factors contributing to housing vacancies in old town Incheon in South Korea. In particular, the research focuses on examining the effects of multiple levels of factors on housing vacancies in a comprehensive way; the three levels of factors were identified with a literature review including housing (Level 1), Neighborhood (Level 2), and Region (Level 3). A multi-level logistic regression model was used to examine the relationship between 13 factors in three spatial levels and housing vacancies. As a result, the factors in all three levels were able to explain housing vacancies including site area and shape, proximity to major roads (Level 1), ratio of houses in designated urban renewal area and slope (Level 2), and ratio of the elderly living alone, land price, changes in land price and ratio of new houses (Level 3). These results show that the combination of the physical inferiority of the housing site and the neighborhood environment and the economic and social vulnerability of the region is likely to increases the number of vacant houses. This study also suggested that a multi-dimensional policy strategy is needed to solve the problem of housing vacancies, and urban policies, such as supplying new housing or urban renewal area designation, should be carefully implemented in a way not to create housing vacancies.

• Journal of Korean Society of Forest Science
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• v.100 no.3
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• pp.466-475
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• 2011

This study purposed to analyze the spatial pattern and the amount of carbon emission at the deforestation area based on the administrative and GIS data. The total size of deforestation area in last nine years (2000-2008) was about 649 ha, and it was occurred annually about 72 ha. The occurrence rate of deforestation per administrative area in Wonju was about 0.74%. It was 0.34% higher than that of Kwangwondo, and 0.06% less than that of National rate. On the other hand, the forms of deforestation by purpose were not related to the administrative district unit. The number of deforestation forms was highest at settlements. second most frequent form is other land. Grassland showed the lowest score. In addition, the deforestations were more occurred which is closed to the existing housing and building rather than roads. The number of deforestation was 1.2 times higher based on 300m. Seventy percent of deforestation was occurred which is less than 0.5 ha in size, and it increased to 91% when the size is less than 1ha. The total size of theoretical carbon emission based on deforestation area was estimated at 23,424 tc, and average annual carbon emission was estimated by 2,603 tc. Carbon emission per ha was 36.1 tC/ha. This study results will be useful to construct the greenhouse gas statistical verification system against the Post-2012 by GIS.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.3
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• pp.346-354
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• 2021

Since 2015, Blockchain has experienced rapid development throughout the world, institutions including Central Banks, Government Departments, Commercial Banks, IT Giants are all accelerating their exploration on Blockchain, and investment on Blockchain related R&D departments and start-up companies also shows explosive growth. This paper studies the impact of blockchain technology on banks' conventional trade settlement methods and describes blockchain technology in term of its concepts, advantages, and disadvantages. It also studies the application processes of blockchain technology combined with conventional trade settlement methods (remittance, collection, and L/C), and analyzes the positive and negative impacts of blockchain technology on the conventional trade settlement methods. In addition, this paper lists the blockchain application cases, analyzes the technology development status and existing problems, and puts forward suggestions and measures for the development of blockchain finance in China based on the case analysis and impact research.

• The Journal of the Korea Contents Association
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• v.21 no.5
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• pp.877-888
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• 2021

This study used three types of temporary shelters, tents, and prefabricated houses provided by the Chinese government for victims after the Wenchuan earthquake in 2008 as case study objects. Through literature review, 12 evaluation items were selected from the social, economic, and environmental elements of the sustainability of residential space design to analyze and evaluate three types of temporary shelters, and derive their respective characteristics and problems. The analysis results show that the temporary centralized settlements and tents had problems such as imperfect infrastructure, poor sanitation, narrow living space, no personal space, and inconvenience in life. Prefabricated houses had problems such as high construction costs, non-environmentally friendly building materials, occupation of arable land, low recycling rate of materials, and environmental pollution by waste. The common problem of the three types of shelters was that the government took the lead in the construction and distribution of shelters, and the disaster victims passively accept government support. Therefore, disaster victims were not actively involved in the construction and management of temporary communities. Secondly, the designs of all three types of temporary shelters did not fully consider the psychological needs of the victims, especially the need for safe and hygienic personal space. Finally, this research proposes improvement plans for the problems in the sustainable design of three temporary shelters and the construction and management of temporary communities.

• The Journal of Engineering Geology
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• v.31 no.2
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• pp.135-148
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• 2021

Ground subsidence risk ratings obtained from the site investigation during pre-excavation stages could be changed depending on the parameters revealed during construction activities. A method of correcting the pre-excavation ground subsidence risk ratings based on the site conditions observed in the field is suggested in this study. The elevation of groundwater table during the excavation may be different from the predicted value depending on the application of waterproofing methods and construction conditions. The drastic drawdown of groundwater table during the excavation could cause ground subsidence due to soil volume decrease related to consolidation or compression of the ground, whereas the rising of groundwater table caused by the intense rainfall may result in a high potential for ground subsidence due to heaving or boiling of the excavation bottom. Excessive displacements of retaining walls or ground settlements may cause ground subsidence, which also results in a high risk of ground subsidence caused by the destruction of buried pipelines. Reevaluation of ground subsidence risk ratings is suggested considering the fluctuation of groundwater table, condition of groundwater leakage, measured ground displacements, and soil types. Finally, the ground subsidence risk rating system is improved for better evaluation by using 12 factors in 5 categories.

• Journal of the Korea Institute of Building Construction
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• v.21 no.6
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• pp.677-687
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• 2021

If a fire breaks out in a building, occupants can evacuate more rapidly if they are able to identify the location of the fire, the exits, and themselves. This study derives the requirements of system development, such as distance non-limitation, a non-additional device, a non-centralized server system, and low power for an emergency, to identify information about the fire and the location of evacuees. The objective is to receive and transmit information and reduce the time and effort of the database for location tracking. Accordingly, this study develops a server-independent system that collects information related to a building fire and an evacuee's location and provides information to the evacuee on their mobile device. The system is composed of a transmitting unit to disseminate fire location information and a mobile device application to determine the locations of the fire and the evacuee. The developed system can contribute to reducing the damage to humans because evacuees can identify the location of the fire, exits, and themselves regardless of the impaired server system by fire, the interruption of power source, and the evacuee's location. Furthermore, this study proposes a theoretical basis for reducing the effort required for database construction of the k-nearest neighbor fingerprint.

• Journal of Cadastre & Land InformatiX
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• v.52 no.1
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• pp.17-36
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• 2022

The purpose of this study is to diagnose problems in the regulation and management of Restricted Development Zone and to prepare a construction plan to convert it to a data-based monitoring system. Unlike other land-use zones, the Restricted Development Zone is a exceptional zone that prohibits all development activities other than the minimum maintenance and must be strictly controlled and managed by the local government. However, the current Restricted Development Zone management is distributed according to the conditions of each local government, and it is not possible to monitor changes in the entire Restricted Development Zone as shown in the survey results. In particular, in this study, by introducing an AI-based monitoring system, MOLIT sends the results of detecting changes across the country at regular time points(monthly and quarterly) to the local governments based on the same regulation standards, and the local governments can be trusted while inputting the regulation results into the system. To propose this methodology, first, a survey and interview were conducted with local government officials and experts. Second, we analyzed cases in which AI analysis was applied to local governments and proposed a plan to improve the efficiency of regulation work according to the introduction of the monitoring system. Third, a plan was prepared to establish a monitoring system based on the advancement of the management information system. This monitoring system can be expanded and applied to land that needs periodic regulation and management in the future, and this study tried to propose a methodology and policy for this.