• Korean Journal of Construction Engineering and Management
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• v.23 no.1
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• pp.64-72
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• 2022

The retaining wall structure is essential for construction work that performs underground excavation. Displacement management of the retaining wall structure is important regardless of the size of the construction. However, in the case of small-scale construction sites with an excavation depth of less than 10m, displacement management of retaining wall structure not properly performed due to problems such as 1) companies' smallness, 2) lack of capacity of construction managers, 3) complexity of installation, dismantling and displacement of measuring instruments. As a result of analyzing previous research, it was analyzed that it is difficult to apply this to a small - scale construction site because most of the previous research has problems in using an expensive 3D scanner or installing many measuring instruments. This study aims to propose a conceptual design of a displacement measurement system for retaining wall structure based on laser sensor and to verify the displacement recognition performance of core technology applied to the conceptual design. A conceptual design was proposed using a 2D laser scanner. As a result of verifying the displacement recognition of the 2D laser scanner, a displacement of 15mm was analyzed to be sufficiently understandable. In the future, if the proposed conceptual design is developed and applied to the small-scale construction site, it is thought that it will contribute to the reduction of safety accidents at small-scale construction sites.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.2
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• pp.175-183
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• 2023

In a broadcasting market environment that has a close interdependence between platform operators and content operators, problems such as conflicts over program usage fees, and home shopping transmission fees are intensifying. This study attempted to analyze the environment of the domestic broadcasting market and present implications, analyze the cause of user fee conflict between the platform and PP, and propose detailed alternatives to resolve user fee conflict disputes. The results of environmental analysis on the domestic broadcasting market are as follows. First, the growth engine of the broadcasting industry has changed to direct resources such as service usage fees and content fees, and commerce is increasing. Second, as hegemony in the domestic broadcasting market changes from terrestrial to paid broadcasting and OTT, monopolies in the entire broadcasting area are being dismantled by voluntary entry. Third, the need to overhaul the existing regulatory system is increasing due to the dismantling and reorganization of the existing broadcasting market. On the other hand, this study proposed a strategy to diversify the profit structure of PP, supply program after pre-contracting, and strengthen CPS bargaining power in order to resolve disputes between paid broadcasting platforms and PP sharply. In particular, as strategies to strengthen CPS bargaining power of small and medium-sized SOs, it proposed to jointly improve CPS-related systems through IPTV and individual SOs, to redefine fees for programs and to voluntarily use programs.

• Journal of Advanced Navigation Technology
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• v.28 no.3
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• pp.348-355
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• 2024

A current source capable of stably supplying current as a measurement medium is required in order to measure and test important facilities that require large-scale measurement current, such as a control element drive mechanism control system(CEDMCS), in case of dismantling a nuclear power plant. However, it can provides only voltage power as a source, not current, although direct voltage controlled constant current source is essential to test major equipment. That kind of source is not available to supply stable constant current regardless of load variation. It is just voltage supplier. Developing current source is not easy other than voltage source. Very large-scale current source up to ampere class more than such ten times of normal current is inevitable to test above mentioned equipment. So, we developed large-scale current source which is controlled by input DC voltage and supplies constant stable current to object equipment according to this requirement. We measured and tested nuclear power plant equipment using given real site data for a long time and afforded long period load test, and then proved its validity and verification. The developed invetion will be used future installed important equipment measuring and testing.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.37 no.4
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• pp.51-59
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• 2019

This study aims to examine the design and construction methods of movable Pavilions. Through the literature analysis, the setting up of the construction background, location and direction, size and composition, materials and construction methods were analyzed. The results are as follows; First, the movable pavilion is designed to enjoy a wide range of views. It was a creation that reflected the way in which the ideal life was pursued based on the experience of enjoying scenery rather than owning one's own house and running a pavilion. Second, the formation of movable pavilion was intended to enjoy the scenery by season without restrictions on time and place. It can also relieve the hassle of having to move tools to enjoy the wind every time. Third, the movable pavilion faces to a place with good scenery and determines its position and direction. Most of them were built on a small scale and divided the space for viewing the scenery, playing GO(Baduk), writing poems, and playing musical instruments. Also, wood was used mainly. To reduce the load, roofs and walls were constructed with light materials such as bamboo, straw, thick sheet of oil, and cotton cloth. The construction method was mainly used by the method of fastening for easy coupling and dismantling. When a building was constructed on the upper part of a ship or cart, the wooden structure of a regular pavilion was constructed. Fourth, when comparing the design and construction characteristics of ordinary pavilion and movable pavilion, the movable pavilion is easy to see for contrast purposes, so there is no limit to setting the location and direction. Instead, more stringent systems and techniques were called for, because as mobility forces should be considered, structurally measures to withstand loads, and they should satisfy their function and form as pavilion.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.72-80
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• 2004

Electrolytic dissolution study was carried out to evaluate the applicability of electrochemical decontamination process using a neutral salt electrolyte as a decontamination technology for the recycle or self disposal with authorization of large amount of metallic wastes contaminated with uranium compounds generated by dismantling a retired uranium conversion plant using SUS-304 and Inconel-600 specimen as the main materials of internal system components of the plant. The effects of type of neutral salt as an electrolyte, current density, and concentration of electrolyte on the dissolution of the materials were evaluated. On the basis of the results obtained through the basic inactive experiments, electrochemical decontamination tests using the specimens contaminated with uranium compounds such as $UO_2$, AUC (ammonium uranyl carbonate) and ADU (ammonium diuranate) taken from an uranium conversion plant were peformed in $Na_2SO_4$ and $NaNO_3$ solution. It was verified that the electrochemical decontamination of the dismantled metallic wastes was quite successful in $Na_2SO_4$ and $NaNO_3$ neutral salt electrolyte by reducing $\beta$ radioactivities below the level of self disposal with authorization within 10 minutes regardless of the type of contaminants and the degree of contamination.

• The Journal of Art Theory & Practice
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• no.8
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• pp.123-144
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• 2009

The history of art during the first half of the last decade was founded the discussion with highly impressive and confident. The art might establish its unique area based on self recognition at that era. The self-confidence of modern art may be possible on enlightenment, which is the firm relationship for knowledge and reality. However the faith of modernism which shows rational tendency, objective, and the existence of universal knowledge has been drastically doubted and criticized thereafter. A internal ideological system which had leaded the modern art was exhausted. Postmodernism revolved to the dramatic openness leaning against the deoedipalizational confession. According to the dissipation of the vitality of modern art postmodern art has been evolved and then various phenomena which follow the trends has been emerged. The avant-garde and resisteive attribute of modern art was diluted fast due to the influx of popular culture. As time goes it can be attracted by spectacle taste than metaphysical peculiarity. It has to inevitably justified the drift of light and quick themes, contents, and images. Such as these phenomena realistically shows fact that postmodern art had been failed to open a new chapter of consilience which intermediates beauty and usual communication to overcome the solipsism of modernism. A trial to pursuit the opened esthetics conceived more 'heroic' 'Star-Subject' than before by dismantling the modern 'Hero-Subject'. Postmodernism has been recorded as a regression of art, which is the technology of profound spirit that mitigates antagonism and confrontation and mediates mutual encountering of human being. Prevailing of postmodern freedom had been accompanied by popularity, osetentation consumption, marketing, gambling level exitement, mixtures of desires with price fluctuations. We witness 'self-confinement' and 'lasting absence of exit' phenomena in postmodernism ideology and practice. We have to deal postmodernism as an 'ideology which closes the discussion for the future' in the context of 'absence of way' at this point. We are going to investigate how postmodern ideology and practice takes part in the prospection beyond thereafter through discussion. We also pay attention to the 'absence of prospection' as a internal problem in itself nevertheless mention the three merge points such as tradition or memory, earthy thought, the self who confrontation others as the clue of prospecting thought which is allowing coming over postmodern absence.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.4
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• pp.28-36
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• 2021

It is known that buried rebars inside concrete structures are protected from corrosion due to passive layer. It is very important to delay the timing of corrosion or evaluate a detection of corrosion initiation for the purpose of cost-beneficiary service life of a structure. In this study, corrosion monitoring was performed on concrete specimens considering 3 levels of cover depth(60 mm, 45 mm, and 30 mm), W/C(water to cement) ratio(40.0%, 50.0%, and 60.0%) and chloride concentration(0.0%, 3.5%, and 7.0%). OCP(Open Circuit Potential) was measured using agar-based socket type sensors. The OCP measurement showed the consistent behavior where the potential was reduced in wet conditions and it was partially recovered in dry conditions. In the case of 30 mm of cover depth for most W/C ratio cases, the lowest OCP value was measured and rapid OCP recovery was evaluated in increasing cover depth from 30 mm to 45 mm, since cover depth was an effective protection against chloride ion ingress. As the chloride concentration increased, the effect on the cover depth tended to be more dominant than the that of W/C ratio. After additional monitoring and physical evaluation of chloride concentration after specimen dismantling, the proposed system can be improved with increasing reliability of the corrosion monitoring.

• Journal of the Korean Society of Systems Engineering
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• v.17 no.1
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• pp.65-75
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• 2021

When the decommissioning of South Korea nuclear power plants is promoted in earnest with the permanent shutdown of Kori Unit 1 in 2017, a large amount of various types of radioactive waste will be generated. For minimal generation and safe management of decommissioning waste, the waste should be made by appropriate classification of the dismantling waste characteristics in accordance with physical, chemical and radiological characteristics to meet the acceptance criteria of disposal facilities. Replacing the preliminary inspection at the site for the compliance of the waste acceptance criteria (WAC) of medium and low-level radioactive waste with the generator's own radioactive waste certification program (WCP), from the perspective of disposal, the optimization of waste management at the national level contributes to the efficient availability of disposal, such as the processing of non-conforming radioactive wastes at the site. To this end, it is important to evaluate radioactivity in each system and area such as nuclear reactors before decommissioning is carried out in earnest, and the prior removal of harmful wastes is important. From waste collection to waste disposal, decommissioning waste should be managed at each stage in consideration of the acceptance criteria of disposal facilities to minimize the generation of non-conforming waste.

• Journal of the Korea Institute of Building Construction
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• v.22 no.4
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• pp.403-414
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• 2022

Many studies have been conducted on asset management of public facilities, as the importance of such management has been increasing. This basic study aims to present strategies for the practical use of public asset management, and seeks to propose efficient management and utilization measures from a cost perspective by comparing and analyzing the importance and impact relationship between cost items for public asset management. In this study, 19 sub-items and the top 4 items were chosen by deriving cost factors based on the previous literature. A survey was conducted, and the results of the survey were analyzed by using the Analytic Hierarchy Process(AHP) and Interpretive Structural Modeling (ISM) methods. The AHP was used to derive the priority between items, and ISM was used to identify major groups and mutual influences. As a result, those items showing both high priority and high importance, such as user cost, dismantling/disposal cost, replacement cost, maintenance/repair cost, etc. are determined as priority items to be considered for public asset management of public facilities. Also, it is necessary to minimize the impact on other items in public asset management by those items which are impacted less by other items but have significant impact on the items such as initial construction costs, conceptual design costs, construction costs, and supervision costs. It is expected that the results and analysis methods presented in this study can be used to provide strategies for asset management of public facilities.

• Resources Recycling
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• v.31 no.6
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• pp.81-91
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• 2022

The use of lithium-ion batteries increases significantly with the rapid spread of electronic devices and electric vehicle and thereby an increase in the amount of waste batteries is expected in the near future. Therefore, studies are continuously being conducted to recover various resources of cathode active material (Ni, Co, Mn, Li) from waste battery. In order to recover the cathode active material, black mass is generally recovered from waste battery. The general process of recovering black mass is a waste battery collection - discharge - dismantling - crushing - classification process. This study focus on the crushing/classification process among the processes. Specifically, the particle size distribution of various samples at each crushing/classification step were evaluated, and the particle shape of each particle fraction was analyzed with a microscope and SEM (Scanning Electron Microscopy)-EDS(Energy Dispersive Spectrometer). As a result, among the black mass particle, fine particle less than 74 ㎛ was the mixture of cathode and anode active material which are properly liberated from the current metals. However, coarse particle larger than 100 ㎛ was present in a form in which the current metal and active material were combined. In addition, this study developed a PBM(Population Balance Model) system that can simulate two-species mixture sample with two different crushing properties. Using developed model, the breakage parameters of two species was derived and predictive performance of breakage distribution was verified.