• Journal of the Korean GEO-environmental Society
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• v.23 no.12
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• pp.17-23
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• 2022

This paper analyze the precast panel retaining wall's safety factor changes based on the numerical analysis using PLAXIS 2D software. Numerical analysis conditions include construction method, nail and panel fixing method, backfill material compaction conditions, rainfall conditions. The classification according to the construction method of the precast panel retaining wall includes the top-down and bottom-up methods. The difference between the top-down and bottom-up methods is the presence or absence backfill material and the ground excavation method. The top-down method involves vertically excavating the ground and attaching the panel using mortar, but in the bottom-up method, the ground is vertically excavated and harden the backfill material. As a result of numerical analysis, the top-down method secured a higher safety factor in all cases except the rainfall conditions.

• Korean Management Science Review
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• v.31 no.1
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• pp.41-48
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• 2014

This study presents a bottom-up approach for analyzing greenhouse gas (GHG) emissions for the shipbuilding industry in Korea. The overall procedures for deriving GHG emissions from the Korean shipbuilding industry are presented. Based on the long-term forecast on energy demands of the Korean shipbuilding industry, reference energy system (RES) and energy balance (EB) for the shipbuilding process are derived for bottom-up modeling.

• Journal of Korean Society of Rural Planning
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• v.21 no.3
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• pp.67-84
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• 2015

Although the bottom-up rural area development project was conceived with great expectations, the general evaluation of the project so far reveals that it does not significantly differ from projects carried out in a top-down manner. This paper examines the nature of the bottom-up rural area development project with a focus on its background, including the roles of authority and project participants. Results revealed that the project was designed to be implemented in line with the state affairs ideology of the leader in a negative position of bureaucratic society. Though the form of implementation for the project seemed bottom-up as seen in the process of the roles and authorities in supporting organizations the top-down method of implementation can be seen in the authorities and roles of the central government. It was also noticed that the private sector, designed to elicit participation of various experts, looked to be managed and controlled by public organizations. The abovementioned signifies that the Korea rural area development project has been implemented not in a bottom-up manner but rather in an ever-strong top-down manner, which means that the central government holds more responsibility for the project's results, evaluation, and discussions. Furthermore, as seen in the background of the project, policies have been implemented in a top-down manner without the confidence of the bureaucratic society. Therefore, in order to implement a proper bottom-up rural area development project, there is a need for the bureaucratic society to have confidence in the rural societies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.758-764
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• 2018

Digital documents such as patents, scholarly papers and research reports have author keywords which summarize the topics of documents. Different documents are likely to describe the same topic if they share the same keywords. Document clustering aims at clustering documents to similar topics with an unsupervised learning method. However, it is difficult to apply to a large amount of documents event though the document clustering is utilized to in various data analysis due to computational complexity. In this case, we can cluster and connect massive documents using keywords efficiently. Existing bottom-up hierarchical clustering requires huge computation and time complexity for clustering a large number of keywords. This paper proposes an inverted index based bottom-up clustering for keywords and analyzes the results of clustering with massive keywords extracted from scholarly papers and research reports.

• Journal of the Korean Geotechnical Society
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• v.36 no.12
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• pp.99-106
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• 2020

Man-made slope is inevitable to make a new road, which may result in environmental problems as well as collapse of slope. To prevent these problems, various methods such as geogrid reinforced retaining wall, precast concrete-panel retaining wall, and so on, have been introduced and developed. Among these methods, this paper presents the evaluation of field application of precast concrete-panel retaining wall attached to in-situ ground (so called top-down) compared to the conventional construction method of precast concrete-panel retaining wall (so called bottom-up) through the field test and numerical analysis. As a result, the safety factor of both methods in final stage is similar, however, top-down method guarantees the slope stability during the construction compared to bottom-up method.

• Korean Management Science Review
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• v.32 no.1
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• pp.101-111
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• 2015

The glass production is classified into an energy intensive industry. This study develops a systematic procedure to derive Greenhouse Gas (GHG) emission inventory for the Korean glass industry. Based on the bottom-up approach in which the energy intensity in each production process is characterized, the EBs (energy balances) of glass production processes are derived. And the GHG emission is calculated for each of four types of glasses-flat glass, container glass, fiber glass, and LCD glass.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.1
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• pp.18-26
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• 2014

Purpose: The purpose of this study was to estimate the cost of dental implant using the bottom-up approach with the current data from dental clinics. Materials and methods: In this study, direct and indirect costs required for each treatment were calculated using the bottom-up approach. In the bottom-up costing, the average monthly total cost of dental clinic includes labor and material costs, administrative expenses, medical malpractice costs, and opportunity costs of invested capital. For the dental implant cost components, those include direct costs (labor costs, laboratory costs, material costs, depreciation or other operating costs), indirect costs (administrative costs), and the opportunity costs of investment for dental clinic. Results: Dental implant costs of metal crown, porcelain crown and over-denture were 1,449,000 won, 1,583,000 won, and 2,471,000 won respectively. The proportion of cost components was as follows. The labor cost were 50%, and material, administrative and other cost were 33%, 15% and 2%, respectively. For direct, indirect and investment cost, the ratio were 83%, 15% and 2%, respectively. Conclusion: The labor costs were evaluated to comprise largest proportion (about 50%, 730,000 won). Dental implant cost using Bottom-up costing was 1,450,000 won for metal crown and 1,580,000 won for porcelain crown.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.404-411
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• 2002

The PSC 2-span-continuous-bridge by Up-Down Method on construction process is used for this research. It is measured the strain of lower-steel-plate at continuous section on the active range of negative moment at the stage of introducing compressive stress to bottom-plate and compared with results of structural analysis. On the basis of these results, it is confirmed the introduced compressive stress tか bottom-plate. The object of this research is presenting the degree of continuity at the stage of lifting up process.

• Journal of Energy Engineering
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• v.24 no.1
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• pp.58-68
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• 2015

A marginal abatement cost analysis has been conducted to analyze the effects of abatement measures on greenhouse gas (GHG) emissions for the Korean residential sector. A bottom-up model using MESSAGE has been developed by defining the energy demand and constructing the reference energy system for the residential sector. A great amount of activity data has also been analyzed. Abatement potentials and related costs of individual abatement measures are investigated. The result from the marginal abatement cost analysis may provide general guidelines and procedures for the establishment of GHG abatement polices.

• KEPCO Journal on Electric Power and Energy
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• v.8 no.2
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• pp.97-101
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• 2022

In this study we investigated the gas to solid heat transfer of bubbling fluidized bed bottom ash cooler installed at the Donghae power plant in South Korea. Several different analyses are done through 1-D calculations and 3-D CFD simulation to predict the bottom ash exit temperatures when it exits the ash cooler. Three different cases are set up to have consideration of unburnt carbon in the bottom ash. Sensible heat comparison and heat transfer calculation between the fluidization air and the bottom ash are conducted and 3-D CFD analysis is done on three cases. We have obtained the results that the bottom ash with unburnt carbon is exiting the ash cooler, exceeding the targeted temperature from both 1-D calculation and 3-D CFD simulation.