• Journal of Family Resource Management and Policy Review
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• v.27 no.3
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• pp.67-75
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• 2023

This study will examine the changing nature of housework by analyzing participation in domestic work among 30-somethings according to generational and life cycle characteristics. To this end, 2,687 men and women in their 30s were taken from the 2020 Family Status Survey data, and a latent class analysis was conducted to categorize their participation in housework. The subjects were categorized into three groups: overall non-participation (18.05%), overall participation (59.96%), and intensive cleaning participation (21.99%). Gender, employment status, family life cycle, and attitudes about gender roles were significantly related to participation in housework. Men were more likely to be in the overall non-participation group, while women were more likely to be in the overall participation group. Individuals in the pre-formative period of the family life cycle were more likely to be in the overall non-participation group, while those in the formative and expanding periods were more likely to be in the overall participation group. The results of this study suggest that gender inequality in housework is common in the younger generation; the results also show that, in the same generation, individual participation in housework differs according to family life cycle.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.3
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• pp.323-334
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• 2008

According to the delivery condition, the breakage of a product occurs when it is delivered to the customers. Therefore product's makers evaluate the durability under the delivery process by accelerated life testing. In order to conduct this accelerated life testing accurately, it is very important to identify the acceleration-factor exactly between on-road and accelerated life test condition. In this paper, the acceleration-factor is identified by applying linear damage summation law, rain-flow cycle counting and Dirlik theory under the conditions of the random vibration. And approximated FEM model of the connecting-pipe to the compressor is developed for fatigue analysis. This model is finally verified by comparing the experiment results to the numerical analysis results.

• Development and Reproduction
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• v.19 no.4
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• pp.227-234
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• 2015

The objective of this study was to investigate the expression of bovine luteum expressed sequence tags (ESTs), vascular endothelial growth factor (VEGF), and tumor necrosis factor receptor 1 (TNFR1) and the presence of functional ESTs in the bovine corpus luteum (CL) during different stages of the estrus cycle. Reverse transcription-polymerase chain reaction (RT-PCR) analysis showed a difference in the expression of ESTs during the CL stage. Concentration of ESTs in the CL tissue increased significantly from the mid-luteal stage and decreased thereafter. RT-PCR analysis showed higher levels of the EST genes in the CL of the mid-luteal stage than in other stages, and the same level of expression of VEGF. Immunohistochemistry analysis of the tissue from CL formation to regression showed low cytosol and aggregation of the nucleus. And activity caspase 3 (apoptosis detector) was most strongly detected in the CL1 stage of bovine. During the estrous cycle, the cytosol was magnified and differentiation of the nucleus was clearly manifested. The ESTs affected the CL, and the relationship between VEGF and TNFR1 played a pivotal role for CL development and activation, dependent on the stage of CL. These results suggest local production of ESTs, the presence of functional ESTs in the bovine CL, and that ESTs play a role in regulating the function of cell death in bovine CL.

• International Journal of Automotive Technology
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• v.5 no.4
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• pp.297-302
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• 2004

This paper presents the low cycle thermal fatigue of the engine exhaust manifold subject to thermo-mechanical cyclic loading. As a failure of the exhaust manifold is mainly caused by geometric constraints of the less expanded inlet flange and cylinder head, the analysis is based on the exhaust system model with three-dimensional temperature distribution and temperature dependent material properties. The result show that large compressive plastic deformations are generated at an elevated temperature of the exhaust manifold and tensile stresses are remained in several critical zones at a cold condition. From the repetition of these thermal shock cycles, maximum plastic strain range (0.454%) could be estimated by the stabilized stress-strain hysteresis loops. It is used to predict the low cycle thermal fatigue life of the exhaust manifold for the thermal shock test.

• Journal of the Korea Society of Computer and Information
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• v.22 no.12
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• pp.145-153
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• 2017

Systemic management is required at each phase of the C4I system life cycle to achieve information advantage in the battlefield through stable operation of the C4I system under the NCOE. In particular, the maintenance phase is the longest period of the C4I system life cycle, and it is easy to utilize and analyze data such as faults that occur during system operation. However, according to the previous research, the maintenance is evaluated as a phase in which the definition and management of comprehensive indicators are insufficient compared to other phase. In this paper, we propose the method of C4I Maintenance Priority decision using Maintenance metric. As a result of modifying the Naval Tactical C4I System's preventive maintenance cycle according to the priority, the total number of faults is reduced and the maintenance efficiency is improved.

• Journal of Navigation and Port Research
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• v.32 no.1
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• pp.29-35
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• 2008

As the seriousness of the global environment is gaining our attention recently, studies on application of LCA(Life Cycle Assessment) to ship are being carried dynamically in various industry fields. However domestic study on LCA was not carried out in various fields. This study was carried out to examine the application of LCA to ship and was focused on the ship operation inventory analysis especially in life cycle assessment. Two training ships of Mokpo maritime university were adopted as ship models. Actual voyage data of at last several years was used to analysis the ship's exhaust gas inventory. The analysis shows how many weight of gas being exhaused per 1 gross tonnage and per 1 trainee in the training ships.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.145-150
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• 2007

This study is a LCC case analysis on the school one of the BTL projects which is constructed by private organizations and rented to government. According to the RFP to make out documents, it is performed the case analysis based on the results of LCC calculation about maintenance & conservation costs; repairing costs and replacement costs. It is analyzed LCC on maintenance & conservation costs for 20 years(rent period) and 65 years(life cycle). As a result of LCC analysis, about more than 50% of total LCC are architectural works and the rest of them are machinery works, electric works, and civil works in the order. And it is also suggested some problems and their solutions to perform LCC analysis on the current BTL projects of school.

• Journal of the Korean Society of Safety
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• v.27 no.4
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• pp.115-120
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• 2012

In order to establish preventive maintenance standards through analysis & reliability prediction of about 60,000pcs of 20kindsof relays and contractors used for Seoul subway trains, several life prediction methodologies were applied. Firstly, Occurrence, Severity, Detection were defined and predicted by applying operation characteristic of EMU to the number of actions of relays & contactors which the manufacturers generally offer as the life cycle data. Secondly, failure distribution and average life of parts were analyzed through interpretation of field data based on a lot of experience which had built up in the field for a long time. Finally, using the 217PLUS standard as a reliability prediction program, comparative analysis of use reliability and inherent reliability was done through reliability prediction at the part level and system level.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.9 s.180
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• pp.2183-2190
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• 2000

A thermal aging is observed in a primary reactor cooling system(RCS) made of a casting stainless steel when the RCS is exposed for long period at the reactor operating temperature, 290~3300C An investigation of effects of thermal aging on a low cycle fatigue characteristics included a stress variations caused by a reactor operation and trip, is required. The purpose of the present investigation is to find an effect of a thermal aging of the CF8M on a low cycle fatigue life. The specimen of CF8M are prepared by an artificially accelerated aging technique holding 300 and 1800hr at 4300C respectively. The low cycle fatigue tests for the virgin and two aged specimens are performed at the room temperature for various strain amplitudes($\varepsilon$ta), 0.3, 0.5, 0.8, 1.0, 1.2 and 1.5% strain. Through the experiment, it is found that the fatigue life is rapidly reduced with an creasing of the aging time. The experimental fatigue life estimation formulas between the virgin and two aged specimen are obtained and are proposed to a analysis purpose.

• Korean Journal of Microbiology
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• v.44 no.4
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• pp.299-304
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• 2008

Monocytic cells in myeloid lineage are known for latent site of HCMV Previous studies have suggested that HCMV regulates cell cycle progression in a variety of cells, but studies in monocytic cells are limited. In this study, we attempted to understand cell cycle changes after HCMV infection in the monocytic cell lines. Flow cytometric analyses using propidium iodide revealed that the proportion of G0-G1 phase was increased and the proportion of S phase decreased in HCMV-infected THP-1 cells, but not in HL-60 cells. BrdU-incorporation assay supported that cell proliferation was inhibited in HCMV-infected THP-1 cells by inhibition of de novo DNA synthesis. Western blot analysis revealed that p21, inhibitor of cell cycle progression from G1 phase to S phase, was induced in HCMV-infected THP-1 cells but not in HL-60 cells. Thus, HCMV inhibited cell pro-liferation by arresting the cell cycle at G0-G1 phase through induction of p21 protein in promocytic THP-1 cells.