• Steel and Composite Structures
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• v.47 no.4
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• pp.523-537
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• 2023

This paper proposed a new self-centering brace (SCB), which consists of four post-tensioned (PT) high strength steel strands and energy absorbing steel plate (EASP) clusters. First, analytical equations were derived to describe the working principle of the SCB. Then, to investigate the hysteretic performance of the SCB, four full-size specimens were manufactured and subjected to the same cyclic loading protocol. One additional specimen using only EASP clusters was also tested to highlight the contribution of PT strands. The test parameters varied in the testing process included the thickness of the EASP and the number of EASP in each cluster. Testing results shown that the SCB exhibited nearly flag-shape hysteresis up to expectation, including excellent recentering capability and satisfactory energy dissipating capacity. For all the specimens, the ratio of the recovered deformation is in the range of 89.6% to 92.1%, and the ratio of the height of the hysteresis loop to the yielding force is in the range of 0.47 to 0.77. Finally, in order to further understand the mechanism of the SCB and provide additional information to the testing results, the high-fidelity finite element (FE) models were established and the numerical results were compared against the experimental data. Good agreement between the experimental, numerical, and analytical results was observed, and the maximum difference is less than 12%. Parametric analysis was also carried out based on the validated FE model to evaluate the effect of some key parameters on the cyclic behavior of the SCB.

• Steel and Composite Structures
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• v.44 no.6
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• pp.899-912
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• 2022

To study the seismic performance of the all-steel buckling-restrained brace (BRB) using the novel soft steel LY315 for core member, a total of three identical BRBs were designed and a series of experimental and numerical studies were conducted. First, monotonic and cyclic loading tests were carried out to obtain the mechanical properties of LY315 steel. In addition, the parameters of the Chaboche model were calibrated based on the test results and then verified using ABAQUS. Second, three BRB specimens were tested under cyclic loads to investigate the seismic performance. The failure modes of all the specimens were identified and discussed. The test results indicate that the BRBs exhibit excellent energy dissipation capacity, good ductility, and excellent low-cycle fatigue performance. Then, a finite element (FE) model was established and verified with the test results. Furthermore, a parametric study was performed to further investigate the effects of gap size, restraining ratio, slenderness ratio of the yielding segment, and material properties of the core member on the load capacity and energy dissipation capacity of BRBs.

• Journal of Platform Technology
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• v.12 no.2
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• pp.45-57
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• 2024

Smart cities are the product of modern urban planning that seeks to innovate information and communication technology and improve the quality of urban life. For the efficient operation of smart cities, data collected, stored, and processed in real time is a key resource. Therefore, data from smart cities collected in various fields must be managed safely, and personal information protection is paramount. In this study, a smart city data security model using blockchain technology was proposed to safely manage smart city data. The proposed model integrates IPFS into the blockchain network to distribute and store data to ensure data confidentiality and integrity, and encrypts data using CP-ABE to efficiently control access to data from users. In addition, privacy was guaranteed while enhancing the usability of data by using Homomorphic Encryption with data access control policies.

• Journal of Nutrition and Health
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• v.44 no.6
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• pp.551-561
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• 2011

Given that household food security issues have become the concern of the Korean society, this study aimed to develop food security measures for the Korean population. Based on the literature reviews on previously developed food security measures, the 18-item US household food security survey module (US HFSSM) was adapted. The developed food security measures was assessed by qualitative validity method. It was evaluated and modified by face validity by expert focus groups belong to university, public health center, and government agencies and by cognitive interview by 40 subjects with low household income who live in an urban community and are participants in welfare programs of local districts. Then, it was reviewed and revised by the National Institute of the Korean Language and the advisory committee for nutrition survey of Korean National Health and Nutrition Examination Survey (KNHANES). The results showed that the developed questionnaire items were well adapted by expert focus groups and general subjects, showing the feasibility of measuring food security with the developed measures although there were discrepancies in some expressions of questionnaire items between experts focus groups and general subjects. The study to assess reliability and quantitative validity of the developed food security measures should be further needed to examine its application for KNHANES.

• Journal of the Korean Professional Engineers Association
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• v.16 no.1
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• pp.20-34
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• 1983

A phenomenon in the unplanned urban sprawl of Cheong-ju city has to be rest-rained from disposing and to develop, though progress in urbanization inevitably decreases rural area. So, this thesis aims at reviewing, revising and guiding toward the more effective land use planning practice and zoning mechanism and system of Cheong-ju city. I proposed that land use planning should be had several factors and thereupon that Korean zoning mechanism and system including Building Code should be amended because of inducing human activities in buildings and facilities not to demarcate and plan every one of them. First, the factors of urban planning are a rather diversified approach to it than a unified, supplementation of the applicable difference in time between preparing and appling it, a solid controlling system, a micro and macro planning theory and giving serious consideration for the inertia from the existing land use. Second, the applicable amendments for our zoning mechanism including Eluding Code are as follows; a need of reorganization for Zoning Ordinance appricated to different regulation concerning a scale and peculiarity of a oily, a decision of the different earmarked confinement in area to different zone ana from Zoning Ordinance in City Planning Law, a demarcated facilities and the more detailed land use concerning human activies than the exsisting and entrusting decision on the ways and processes of it to every rural city planning committee, a settlement of zone ana area considering for block-unit and Planned Unit Development(P. U. D.), and a need of security jurisprudence in order to solve the zoning regulation rather in City Planning Law than in Building Code that our zoning regulation and controlling system are depended on. According to these applicable amendments to Cheong-ju city, I proposed the conceptions of Cheong-ju city land use planning are as follows; a reinforcement with one cored pattern of urban land use, a selection of gradual urban sprawl by way of city development and renewal, a strengthening accessibility to the core of the city with Plurizing the system of arterial roads, a choice of priority to conservation at the core of tile city and security of open spaces and parking area at the area of the city, a harmonization between development and conservation at the inner ring area that is situated between the core and periphery reserved area in order to develop in the future, a buffered open space situated at the congested area with heterogenous functions, and a completion of urban open space system. The proposal made here so far is for the hope of the better structure of Cheong-ju city that should be granted to the peculiarity developed with educational, cultural, conservative and self-sufficient city functions.

• Journal of Korean Society of Disaster and Security
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• v.13 no.1
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• pp.13-23
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• 2020

In 2005, Urban railway seismic design was introduced in Rep. Of Korea, and many studies on seismic performance evaluation and reinforcement methods were conducted. In accordance with the Enforcement Decree of the Earthquake Disaster Countermeasures Act issued in March 2009, during April 2010 to October 2013, some of local governments established detailed evaluation and reinforcement measures for seismic performance of the urban railway underground structure. Afterwards, the seismic performance reinforcement of the existing urban railway structures was conducted for the sections that a long period of used until the end of 2018, and the reinforcement works are carried out by various methods using the previously studied methods. However, various reinforcing materials and construction methods using have been studied, but the classification research on the construction methods currently applied to reinforcement construction of urban railways is insufficient. The purpose of study is to analysis the cases currently applied to seismic reinforcement construction and to show the characteristics of each construction method, the reasons for its application and problems.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.1
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• pp.1-8
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• 2007

The Anyang River which located in an urban area near Seoul had been managed focusing on supplying home and industrial water and preventing floods, coping with rapid industrialization and urbanization. Consequently, it was changed into a deadly river during 25 years. Its channel was straightened by concrete and water quality deteriorated to BOD 190mg/l. In addition, water quantity has been rapidly decreased and has been drying up. Also, as the river ecosystem, landscape, water-friendly function, and so forth were seriously deteriorated, people turn away from the urban river. From 2001, the master plan under the 10-year has been actively carried out centering on the preceding items, which are healthy river in which fishes inhabit, safe river free from floods and droughts, and pleasant river where citizens visit. As a result, its water quality was remarkably improved by BOD 5mg/l in 2005 and some upper zones were improved enough to allow people to swim. Moreover, various animals including fish and birds gather around the river. Now, the 'Anyang River Restoration Project' is recognized as the first comprehensive and systematic nature-friendly urban river improvement in Korea.

• Journal of the Korea Fashion and Costume Design Association
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• v.12 no.2
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• pp.41-54
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• 2010

This paper aims at studying about spatial structures and formative characteristics of Lucy Orta's fashion design. Her works utilizes the thought related on the architectural space that has been revealed sharp change of the paradigm since the late of 20th century. Lucy Orta against individualism of the urban life, and manufactures portable and moving housing and multi-functional fashion that is paved with individual rest unit and give a sense of security through simple combination among the units. Besides, she has development multiple portable clothing and equipments for the rescuethrough exploiting pioneering high technology. The results of this study can be summarized as the following: 1) refuge habitant creates individual space for physical and mental protection from the urban surrounding, 2) nomadic dwelling shows multi-functional fashion space fit for digital nomads' life style aims at continuous movement, 3) connective nexus and urban life guard are comprise of detachable individual unit in public space for remaking of the bonds, affinity, and relationship, and the complex of rescue clothing and equipments for meeting a challenge of the threat about human existence from uncertain environmental change in the future.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1259-1267
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• 2008

One of the most important item for insuring the stability of ground in urban deep excavation site near by major structure such as subway is displacement control of earth retaining wall. The field monitoring system is classified by two types as manual system and automatic system. The application case of latter type of field monitoring is increased because real time measurement is possible in automatic system and that is correspondent with the recent constructional trend. Though the automatic monitoring system is more useful and advanced than manual monitoring system, accuracy of the system is not verified sufficiently. It was examined that the reliance of automatic monitoring system in this paper through the comparison of monitoring result obtained one of deep urban excavation site in which the each type of monitoring system was executed concurrently. Result of the examination is that the two types of monitoring system is generally alike in view of monitoring result, so the engineering reliance of automatic system was confirmed in case site. This study was researched in restricted one case site, so it is expected more precise analysis from security of more data monitored and progressive study.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.3
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• pp.117-128
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• 2018

The purpose of this study is to identify the physical safety factors and indicators needed to create an age-friendly city where elderly people can live safely and continuously in the era of aging and to evaluate the differences between the five urban communities. For the study, AHP analysis was conducted to calculate the importance of factors and indicators, based on a checklist was made this. A questionnaire survey was conducted on the degree of physical safety perceived by the elderly people aged 65 and older living in Seoul, the difference between the five urban communities in Seoul was confirmed. The research finding are summarized as follows: The score of evaluating grade was the highest in the northwest, northeast was the lowest followed by the northwest, downtown, southeast, southwest, northeast. Among the physical safety factors, the safety of outdoor spaces and buildings was the highest in the downtown and the lowest in the southwest. On pedestrian safety, the downtown was the highest and the lowest was northeast. Regards to the transportation safety, the northwest was the highest and the northeast was the lowest. Housing security was the best in the northwest and the lowest was the northeast.