• Journal of the Korean Society of Safety
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• v.38 no.2
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• pp.104-111
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• 2023

Rolling stock maintenance, which focuses on preventive maintenance, is typically implemented considering the potential harm that may be inflicted to passengers in the event of failure. The cost of preventive maintenance throughout the life cycle of a rolling stock is 60%-75% of the initial purchase cost. Therefore, ensuring stability and reducing maintenance costs are essential in terms of economy. In particular, private railroad operators must reduce government support budget by effectively utilizing railroad resources and reducing maintenance costs. Accordingly, this study analyzes the reliability characteristics of components using field data. Moreover, it resolves the problem of determining an economical replacement interval considering the timing of scrapping railroad vehicles. The procedure for determining the optimal replacement interval involves five steps. According to the decision model, the optimal replacement interval for the onboard signal device components of the "A" line train is calculated using field data, such as failure data, preventive maintenance cost, and failure maintenance cost. The field data analysis indicates that the mileage meter is 9 years, which is less than the designed durability of 15 years. Furthermore, a life cycle in which the phase signal has few failures is found to be the same as the actual durability of 15 years.

• Archives of Pharmacal Research
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• v.29 no.11
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• pp.1032-1041
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• 2006

Extracellular adenosine 5'-triphosphate (ATP) affects the function of many tissues and cells. To confirm the biological activity of ATP on human myeloid leukemic cells, F-36P and HL-60, cells were treated with a variety of concentrations of ATP. The stimulation with extracellular ATP induced the arrest of cell proliferation and cell death. from the analysis of Annexin-V staining and caspase activity by flow cytometry. The Annexin-V positive cells in both cell lines were dramatically increased following ATP stimulation. The expression of P2 purinergic receptor genes was confirmed, such as P2X1, P2X4, P2X5, P2X7 and P2Y1, P2Y2, P2Y4, P2Y5, P2Y6, P2Y11 in both leukemic cell lines. Interestingly, ATP induced intracellular calcium flux in HL-60 cells but not in F-36P cells, as determined by Fluo-3 AM staining. Cell cycle analysis revealed that ATP treatment arrested both F-36P and HL-60 cells at G1/G0. Taken together, these data showed that extracellular ATP via P2 receptor genes was involved in the cell proliferation and survival in human myeloid leukemic cells, HL-60 and F-36P cells by the induction of apoptosis and control of cell cycle. Our data suggest that treatment with extracellular nucleotides may be a novel and powerful therapeutic avenue for myeloid leukemic disease.

• Journal of Ocean Engineering and Technology
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• v.4 no.2
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• pp.100-111
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• 1990

In this paper, fatigue tests were carried out at stress test levels of 461 MPa, 441 MPa, and 431 MPa by using smooth specimen of$2_{1/4}$ Cr-1 Mo steel with the stress ratio(R) of 0.05. The initiation, growth and coalescense process of the major cracks and sub-cracks among the fatigue cracks on the smooth specimen are investigated and measured under each stress level at a constant cycle ratio by the replica technique with optical microscope. Some of the important results are as follows: In spite of the difference of stress levels, the major crack data gather into a small band in the curve of surface crack length and crack depth against cycle ratio N/Nf. The sub-crack data, however, deviate from the band of the major crack. The growth rates, da/dN, of major and sub-crack plotted against the stress intensity factor range, ${\Delta}K$, have the tendency to be compressed on a relatively small band. But it is more effective to predict fatigue life through major cracks. The propagation behavior of surface microcracks on the smooth specimens coincides with that of the specimen having an artificial small surface defect or through crack.

• Korean Journal of Construction Engineering and Management
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• v.13 no.4
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• pp.132-140
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• 2012

Along with the increasing interest in environmental problems such as global warming, the South Korean government has established policies and regulations to reduce the amount of greenhouse gases, targeting a 30% reduction of $CO_2$ compared to business-as-usual levels by 2020. Thus, there have been many studies in construction field to control and reduce the amount of $CO_2$ emitted from buildings. $CO_2$ emission from the building construction could be obtained by using the life cycle assessment(LCA) methodology. In LCA, it is essential to have life cycle inventory(LCI) data of construction materials consisting of $CO_2$ emission data that have been defined and examined in a detailed way in order to obtain more accurate and detailed $CO_2$ emission of buildings. To date, however, the LCI data have been acquired only for the representative materials. Accordingly this study aimed to propose detailed $CO_2$ emission data for steel rebar and H-beam, which are the essential structural steel materials, by strength and type. To accomplish the objective, this study used Input-Output LCA methodology which is based on the Input-Output table. It is believed that the $CO_2$ emission data of steel materials acquired from this study would allow a more accurate assessment of $CO_2$ emission for diverse structural design alternatives.

• Reproductive and Developmental Biology
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• v.37 no.3
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• pp.149-154
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• 2013

The aim of this study was to evaluate the changes of protein patterns in granulosa cells and corpus luteum in ovaries during the estrus cycle in cows. The estrus cycle was devided into five steps of follicular, ovulatory, early-luteal, mid-luteal and late-luteal phases. In results, 61 spots of total 85 spots were repeated on follicular phase and 51 spots of total 114 spots were repeated on ovulatory phase. The 40 spots of total 129 spots were repeated on early-luteal phase and 49 spots of total 104 spots were repeated on mid-luteal phase. Also 41 spots of total 60 spots were repeated on late-luteal phase. On the other hands, the 16 spots were indicated difference in follicular phase and ovulation phase had a difference 10 spots. It was showed difference No. 103 spot in ovulation phase, No. 135 spot in early-luteal phase and No. 175 and 176 spots in mid-luteal phase. Also, the 11 spots were expressed specifically in mid-luteal phase and No. 178 and 179 spots were difference of expression in late-luteal phase. We confirmed that there were 7 spots for ovulation, 4 spots for luteinization and 2 spots for luteolysis. Spot No. 89~93 in ovulation phase were transferrin, and spot No.94~98 were HSP60. Spot No. 103 was Dusty PK, spot No. 135 was OGDC-E2, and spot No. 175 and 176 were Rab GDI beta from luteinization. Spot No. 178 and 179 in luteolysis were vimentin. This results suggest that will be help to basic data about infertility.

• The Journal of Society for e-Business Studies
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• v.2 no.2
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• pp.1-30
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• 1997

In this research, the concept of CM (configuration management) is introduced for proper applications to the life-cycle product data management. In addition, the activities for CM - CM management and planning, configuration identification, configuration control, configuration status accounting, and configuration verification and audit - are described in detail. For the management of distributed configuration data among governments, prime contractors, and subcontractors, development environments and functions for the configuration management information system (CMIS) are proposed.

• Proceedings of the CALSEC Conference
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• 1999.11a
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• pp.85-92
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• 1999

The current R＆B system has a lot of problems caused by complexity of the system and lack of IDE concept among the related offices and organizations. IDE concept is building Integrated database with data which applied standards and digitalized. So R＆D CALS system should be established for the related offices and organizations can use data which created during R＆D life-cycle in IDE. In this paper, I suggested system requirements and system quality factors for building IDE based upon SSS form.

• Proceedings of the KSR Conference
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• 2002.10a
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• pp.376-381
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• 2002

In this study, we have analyzed the cost of korea high-speed rail project. The predicted cost in planning phase and adjustment data to 5th year are collected. Then, predicted cost is compared with adjustment in year/item/system base. We make a project history table for criteria to review project history and research ＆ development activity. We have developed CBS(cost breakdown structure) and allocated adjustment data to them. It is shown that cost prediction related to research St development activity in planning phase is relatively correct.

• Journal of Applied Reliability
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• v.14 no.1
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• pp.21-28
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• 2014

This paper presents an accelerated life test to estimate the lifetime of thermoelectric module for home water purifier. Clamping force and thermal cycle are selected as accelerating variables through the technical review about failure mechanism. It is assumed that its lifetime follows weibull distribution. The relationship, acceleration factor, and BP life at design condition are estimated by analyzing the accelerated life test data.

• IE interfaces
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• v.6 no.2
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• pp.37-51
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• 1993

This paper studies the economic replacement method for production facilities which requires huge investment but are necessary for higher productivity and competability of products. That is, the general models for the decision of economic life of properties which minimizes the total costs throughout the usage life(Life cycle costs) are generated. Main factors which make influences for the decision of econmic life can be divided by three. These are the change of salvage value, repair and maintenance costs, and availability of production facilities with the passage of usage time. In this paper, the real world data for these three factors are collected and analyzed for the extraction of representative standard forms with the passage of time. And general models for economic replacement methods and optimal usage terms are presented through tables with the combination of the standard forms of these three main factors.