• Journal of the Korean Institute of Rural Architecture
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• v.23 no.2
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• pp.9-16
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• 2021

The purpose of this study is to maintain the existing characteristics of the city by utilizing the physical decline status and floating population in small and medium cities residential areas. In addition, it intends to present the direction of flexible urban regeneration and maintenance by reflecting regional characteristics and current status. A total of three data were used in this study. Building data, floating population data, and census output area data were used. Building data and floating population data were classified into five classes. The graded data were joined to the census output area data and analyzed by overlapping the two data. As a result of analysis of 17 residential areas in 5 small and medium cities in Jeollanam-do, 4 types, 2 management models, and 4 indicators could be presented by grade and regional characteristics. This study is meaningful in that it is possible to plan regionally customized urban regeneration/maintenance management plans and projects through the typology of the current status and characteristics of the region, which is an important step in the bottom-up form.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.2
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• pp.183-192
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• 2022

Function and performance degradation in tunnel structure can cause road's function loss, proactive maintenance is needed to prevent the initial damage from progressing to intensified damage. Inspection and diagnosis are implemented in accordance with regulations, but it does not fully reflect maintenance processes such as inspection and diagnosis, planning rehabilitation and carrying out. It was carried out for 5,540 cases inspection and diagnosis result in 1,728 tunnels was analyzed to suggest rational maintenance plan in this study.

• Journal of Periodontal and Implant Science
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• v.23 no.2
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• pp.300-314
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• 1993

Periodontal disease research has been focused on understanding the immunopathologic mechanisms which may operate in the development and maintenance of peiodontal inflammatory changes. Immunologic and inflammatory responses may relate to the etiology and pathogenesis of periodontal disease. In order to research immunopathology of periodontal disease, previous investigators have spent much time on the distribution of lymphocyte subpopulations and NK cells but they have spent less time on the changes of those cells to the periodontal disease severity. The purpose of study was performed to investigate the changes of the distribution of T lymphocytes, B lymphocytes, T lymphocyte subsets, and Natural Killer cells in the gingival epithelium and connective tissue of the periodontal disease with the various clinical parameters including Gingival Index, Sulcular Bleeding Index, and pocket depth. Gingival tissues were obtained from 25 patients with different severity of periodontal disease. Serial cryostat sections displaying a cross section of gingiva were labelled with monoclonal antibody for pan T cells, T cytotoxic/suppressor cells, T helper/inducer cells, pan B cells, and NK cells were develped using an avidin-biotin-peroxidase system. Lymphocyte populations were enumerated in repeatable fields from gingival section. 1. T cells were more increased at grade 1 and 3 than at grade 0 of gingival index (p<0.05). Helper T cells and NK cells were significantly increased at grade 1, 2, 3 than at grade 0(p<0.05). 2. T cells were more decreased at grade 3 and 4 than at grade 1 of sulcular bleeding index (p<0.01, p<0.05). Especially, Natural Killer cells were significantly increased at grade 1, 2, 3, 4 than at grade 0 (p<0.05, p<0.001). 3. The ratios of helper T/suppressor T cells were more decreased at grade 4 than at grade 0 and at grade 4 than at grade 2 of sulcular bleeding index (p<0.05, p<0.05). 4. Helper T cells were significantly decreased at grade II and III than at grade I, however the Natural Killer cells showed a increasing tendency with the increase of the pocket depth, there were no significant differences between each grade of pocket depth. 5. The ratios of helper T/suppressor T cells were tended to be decreased with the increase of the pocket depth, there were no significant differences between each grades of pocket depth. There was a very weak change in the distribution of T lymphocytes, B lymphocytes, T lymphocyte subsets, and Natural Killer cells in the gingival epithelium and connective tissue of the periodontal lesion with the various clinical parameters including gingial index, sulcular bleeding index, and pocket depth. But, the number of T lymphocytes and Natural Killer cells were significantly changed in gingival index and sulcular bleeding index.

• Journal of the Korea Institute of Building Construction
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• v.23 no.1
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• pp.57-68
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• 2023

To maintain the normal function of an aging building, regular inspection, repair, and reinforcement must be performed. However, the form of information and decision-making generated in the current building maintenance stage still depends on inefficient methods. This causes an increase in cost and waste of time in building maintenance. Therefore, this study proposed a COBie-IM document for building inspection and maintenance information management by benchmarking COBie, and suggested a method of checking information by linking it with BIM. In addition, a method for visualizing the designation of colors according to the damage grade of defects occurring in the building was suggested. Through this, we are able to systematically integrate and manage the information generated during inspection and maintenance in the building maintenance stage. This is expected to increase work efficiency by supporting decision-making that determines the priority of repair and reinforcement for defects.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.2A
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• pp.223-231
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• 2008

This research presents a new maintenance planning method for deteriorating bridges considering simultaneously the minimization of the maintenance cost and maximization of the bridge performance. Optimal maintenance planning is formulated as a multi-objective optimization problem that treats the maintenance cost as well as the bridge performance such as the condition grade of the bridge deck, girder and pier. To effectively address the multi-objective optimization problem and decision making process for the obtained solution set, we apply a genetic algorithm as a numerical searching technique and adopt a preference-based optimization method. A numerical example for a typical 5-span prestressed concrete girder bridge shows that the maintenance cost and the performance of the bridge can be balanced reasonably without severe trade-offs between each objectives.

• Korean Journal of Food Science and Technology
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• v.38 no.1
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• pp.10-15
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• 2006

Quality changes of first grade Hanwoo beef were compared with those of third grade Hanwoo beef to investigate effect of initial raw meat quality on maintenance of meat quality during storage for 28 days at $1\;{\pm}\;1^{\circ}C$. Crude fat content of first grade meat was higher, whereas water content was lower, than those of third grade meat. Total bacterial counts of first and third grade beef packaged with polyethylene for 21 days storage at $1\;{\pm}\;1^{\circ}C$ were 106 and $108\;CFU/cm^2$, respectively. Volatile basic nitrogen (VBN) value of first grade meats was lower than that of third grade meat during storage for 28 days at $1\;{\pm}\;1^{\circ}C$. Drip loss percents of first and third grade meats were 4.19 and 6.06% during 14 days storage at $1^{\circ}C$, respectively. L, a, and b values decreased gradually during storage regardless of meat grade, with a value of first grade meat being higher than that of third grade meat at early stage of storage at $1^{\circ}C$.

• Korean Institute of Interior Design Journal
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• v.22 no.1
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• pp.307-317
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• 2013

Elementary school's physical environment is critical to lower grade students. Among the many physical conditions, Toilet, which belongs to health and sanitation category is very important to those who start school for the first time. The purpose of this study is for suggesting the guidelines of toilet design reflecting psychological and behavioral aspects of lower grade students. The research was executed as follows. Firstly, focused survey groups were carefully chosen. Five elementary schools were selected, being all open after 2005 under Seoul Gangseo District Office of Education. Secondly, field study was executed to find out toilet usage, during the period between April to June 2012, by visiting schools to see basic facilities, taking pictures and making actual measurement in each toilets. The architectural analysis was focused on location, moving line, actual size and space zoning, while the interior analysis being on finishing materials and the design of sanitary equipments. And the design elements such as color, lighting fixture, art works or signage were analysed, too. Finally, questionnaire survey was done to find out preferences of lower grade students. As a result, the guidelines of toilet design can be divided into two main parts, Physical and Psychological. For the Physical part, it is necessary for related facilities to be concentrated in order to give easy access. In addition, good ventilation, better lighting and to install sanitary equipments ergonomically are required. Furthermore, safe and clean maintenance should be considered. Psychologically, the design should be directed for making lower grade students come to toilets with comfort and more pleasantly.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.2
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• pp.1-12
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• 2017

In this study, It was purpose to provide preliminary data for extension of the applicability of deep corrugated steel plate composite members by steel grade and shear reinforcement method. From the result of flexural test on deep corrugated plates composite members using GR40 and SS590, positive moment capacity was increased about 28% by SS590 steel. But to change steel grade was proved to have insignificant effects for increasement of negative moment capacity. In the moment test result of same overlapping length, Increasement rate of positive and negative moment capacity was not significantly improved by increasing the number of bolt. It was estimated to be due to the characteristics of bolt connection such as distance between centers of bolts, edge distance of bolt. In the test result on the spacing of shear reinforcement, positive moment capacity was increased and deformation of negative moment was reduced as the distance decrease. In the test result on the shape of shear reinforcement, positive and negative moment resistance was increased about 2% ~ 7% by U shaped shear reinforcement. In conclusion It was estimated that moment capacity of deep corrugated steel plate composite members are depend on steel grade of deep corrugated steel plate, spacing of shear reinforcement and reinforcing bar.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.4
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• pp.96-102
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• 2019

When GGBFS(Ground Granulated Blast Furnace Slag) with high blaine is incorporated in concrete, compressive strength in the initial period is improved, but several engineering problems arise such as heat of hydration and quality control. In this paper, compressive strength and durability performance of concrete with 3,000 Grade-low fineness slag are evaluated. Three conditions of concrete mixtures are considered considering workability, and the related durability tests are performed. Although the strength of concrete with 3,000 Grade slag is slightly lower than the OPC(Ordinary Portland Cement) concrete at the age of 28 days, but insignificant difference is observed in long-term compressive strength due to latent hydration activity. The durability performances in concrete with low fineness slag show that the resistances to carbonation and freezing/thawing action are slightly higher than those of concrete with high fineness slag, since reduced unit water content is considered in 3,000 Grade slag mixture. For the long-term age, the chloride diffusion coefficient of the 3000-grade slag mixture is reduced to 20% compared to the OPC mixture, and the excellent chloride resistance are evaluated. Compared with concrete with OPC and high fineness GGBFS, concrete with lower fineness GGBFS can keep reasonable workability and durability performance with reduced water content.

• Nuclear Engineering and Technology
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• v.40 no.1
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• pp.49-68
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• 2008

The purpose of this paper is to extensively review the condition monitoring (CM) techniques using empirical models in an effort to reduce or eliminate unexpected downtimes in general industry, and to illustrate the feasibility of applying them to the nuclear industry. CM provides on-time warnings of system states to enable the optimal scheduling of maintenance and, ultimately, plant uptime is maximized. Currently, most maintenance processes tend to be either reactive, or part of scheduled, or preventive maintenance. Such maintenance is being increasingly reported as a poor practice for two reasons: first, the component does not necessarily require maintenance, thus the maintenance cost is wasted, and secondly, failure catalysts are introduced into properly working components, which is worse. This paper first summarizes the technical aspects of CM including state estimation and state monitoring. The mathematical background of CM is mature enough even for commercial use in the nuclear industry. Considering the current computational capabilities of CM, its application is not limited by technical difficulties, but by a lack of desire on the part of industry to implement it. For practical applications in the nuclear industry, it may be more important to clarify and quantify the negative impact of unexpected outcomes or failures in CM than it is to investigate its advantages. In other words, while issues regarding accuracy have been targeted to date, the concerns regarding robustness should now be concentrated on. Standardizing the anticipated failures and the possibly harsh operating conditions, and then evaluating the impact of the proposed CM under those conditions may be necessary. In order to make the CM techniques practical for the nuclear industry in the future, it is recommended that a prototype CM system be applied to a secondary system in which most of the components are non-safety grade. Recently, many activities to enhance the safety and efficiency of the secondary system have been encouraged. With the application of CM to nuclear power plants, it is expected to increase profit while addressing safety and economic issues.