• Proceedings of the Korean Reliability Society Conference
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• 2001.06a
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• pp.269-269
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• 2001

Maintainability refers to the ease with which maintenance work can be done. It involves the process of ensuring that products can be easily and safely maintained and that the maintenance support requirement is minimized. When a product has a reasonably long life, the cost of operation and support during that life can greatly exceed the initial capital cost. The value to the customer of optimizing maintainability should be evident. Some effort and expense applied to achieving a product which can be easily and cheaply maintained will make very significant savings in the life cycle costs. In this paper, the International Standard IEC 60300-3-10, which is the application guide for maintainability, is considered. This standard can be used to implement a maintainability program covering the initiation, development and in-service phases of a product. It provides guidance on how the maintenance aspects of the tasks should be considered in order to achieve optimum maintainability. The elements of a maintainability program, which are maintenance policy and concept, maintainability studies, project management, design for maintainability, analysis and prediction methods, maintenance verification and validation, analysis of life cycle cost, maintenance support planning, and collection and analysis of maintenance data, are fully discussed in this paper.

• Computational Structural Engineering : An International Journal
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• v.2 no.1
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• pp.11-17
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• 2002

Cost-effectiveness in design is considered for determining the target reliability of concrete bridges under seismic actions. This objective can be achieved based on the economic optimization of the expected life-cycle cost of a bridge, which includes initial cost, direct losses, and indirect losses of a bridge due to strong earthquakes over its lifetime. A separating factor is defined to consider the redundancy of a transportation network. The Park-Ang damage model is employed to define the damage of a bridge under seismic action, and a Monte Carlo method based on the DRAIN-2DX program is developed to assess the failure probability of a bridge. The results for an example bridge analyzed in this paper show that the optimal target failure probability depends on the traffic volume carried by the bridge and is between 1.0×10/sup -3/ to 3.0×10/sup -3/ over a life of 50 years.

• Steel and Composite Structures
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• v.33 no.6
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• pp.777-792
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• 2019

This paper presents a new efficient approach to estimate the S-N type fatigue life assessment curve for S550 high strength steels under low-cycle actions at -60℃. The proposed approach combines a single set of monotonic tension test and one set of fatigue tests to determine the key material damage parameters in the continuum damage mechanics framework. The experimental program in this study examines both the material response under low-cycle actions. The microstructural mechanisms revealed by the Scanning Electron Microscopy (SEM) at the low temperature, furthermore, characterizes the effect due to different strain ratios and low temperature on the low-cycle fatigue life of S550 steels. Anchored on the experimental results, this study validates the S-N curve determined from the proposed approach. The S-N type curve determined from one set of fatigue tests and one set of monotonic tension tests estimates the fatigue life of all specimens under different strain ratios satisfactorily.

• Proceedings of the Korean Society of Life Science Conference
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• 2008.10a
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• pp.23.2-23.2
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• 2008

• 시스템엔지니어링워크숍
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• s.4
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• pp.17-22
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• 2004

This paper present the brief generation process of system requirements or mart UAV from a development obejective. The current Snart UAV requirements deal with the restricted life cycle from development to test and verification exclusive of full life cycle beacuse of the new technology demonstration research program funded by goverments. The Smart UAV system consists of flight vechicle, avionics, communication link, payload, ground control stationand ground supporting system. In thus paper, top-down flown requirememts are intoduced how to allocate to each sub-system.

• Journal of the Korean Home Economics Association
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• v.38 no.7
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• pp.117-132
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• 2000

The purpose of this study is to develop a computer software titled "Compare & Evaluation Program for Household Consumption". This software is developed in Microsoft Visual Basic 6.0. For the data of this program, the family Income and Expenditure Survey(1998) produced by the National Statistical Office in Korea is used. This program compares income and consumption expenditure for each household with those for standard household according to income level and family life cycle. This program gives information and suggestion for household consumers to manage rational household consumption. Also this study investigates validity and usefulness of the software program by interviewing 20 households used this program.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.13-20
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• 2016

The computerized management system for bridges is required due to the increased service life and number of bridges. This paper provides information and communication technology (ICT) - based bridge management system (BMS) to enable life cycle management through a comparative study with the development trend and function of domestic and foreign BMSs. BMS developed as an operation system combined an internet and mobile program, and was based on GIS technology and an object-based information management system. BMS supports the establishment of long-term strategies and short-term plans based on predicting the life-cycle performance profile and the necessary budget by object-based informatization for the whole life-cycle information of bridges. Useful knowledge information for supporting decision making was derived from the life-cycle management strategies establishment for approximately 6,000 existing bridges. BMS was developed to be applicable to all nationwide road bridges. In addition, it can be used practically to maintain the performance based on accurate maintenance result management, reducing cost by reasonable budget management, and enhancing the convenience and reliability of field data collection.

• Journal of Family Resource Management and Policy Review
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• v.11 no.4
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• pp.93-114
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• 2007

The purpose of this study was to analyze the educational program that is offered on the information menu in the homepage (Familynet) of the Healthy Family-Support Center (HFSC) and suggest developmental directions. For this purpose, first, it deduced that the managerial principles of the education program, from related theories, are included in the family-system, family-structure, family-structure analysis, family life-cycle and ecological system theories. Second, it analyzed the educational programs of 44 local centers that are connected to the homepage (familynet.or.kr) of HFSC. Finally, it suggested developmental directions for managerial improvements of educational programs. As a result, the most popular part in the educational program was parent education, especially the visiting-father education program. The number of couple-related education programs were fewer than those for parent education, because it is difficult for couples to be present at the same time. Family and Self-Cognition programs cover insufficient contents in the parent-education program. Though total program in familylife education is quite large, the number of programs in each separate part is far too small for such a wide subject. So, each part in the program should be made more sufficient. Finally, it suggested the development of an evaluation system and a coaching process as special services for families that are in different development stages and have different family experiences, resources, needs and goals.

• Journal of the Korean Society of Costume
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• v.56 no.3 s.102
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• pp.81-90
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• 2006

The objective of the study is to review trends of clothing export in important countries of the world and thus to know the present stage of clothing export in Korea. For the purpose, changes of export amount, competitiveness and product life cycle were analysed in the countries from the 1960's to the 1990's. The results are as following: First, on the aspect of export amount, industrialized countries lost the lead to newly industrializing countries from the 1960's. Developing countries, as China, win the lead. Second, on the competitiveness aspect, industrialized countries lost competitiveness to newly industrializing countries before the 1960's. And newly industrializing countries were outpaced by China in the export competitiveness from the early 1990's. Third, on the aspect of product life cycle, industrialized countries go first through each period of product life cycle, introduction, growth, maturity and decline, and they all, excluding Japan, sustained period of Maturity for a long time. newly industrializing countries and developing countries go orderly through each period of product life cycle after industrialized countries. As to Korea, duration of each period was short. Specially characteristics of decline period appeared partly in the early 1990's. From the results, the theory of product life cycle, helping to explain changes in production and trade in new product lines, estimated to applicable to clothing export. The phenomena, Italy, Hong Kong and America sustain high competitiveness in the world clothing market for a long time, is needed to be studied carefully. The study about strong points in their clothing industries and competitiveness drive program be to influence Korean export policy in the future.

• Journal of Applied Biological Chemistry
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• v.51 no.6
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• pp.262-271
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• 2008

Natural abundances of stable isotopes of nitrogen and carbon (${\delta}^{15}N$ and ${\delta}^{13}C$) are being widely used to study N and C cycle processes in plant and soil systems. Variations in ${\delta}^{15}N$ of the soil and the plant reflect the potentially variable isotope signature of the external N sources and the isotope fractionation during the N cycle process. $N_2$ fixation and N fertilizer supply the nitrogen, whose ${\delta}^{15}N$ is close to 0%o, whereas the compost as. an organic input generally provides the nitrogen enriched in $^{15}N$ compared to the atmospheric $N_2$. The isotope fractionation during the N cycle process decreases the ${\delta}^{15}N$ of the substrate and increases the ${\delta}^{15}N$ of the product. N transformations such as N mineralization, nitrification, denitrification, assimilation, and the $NH_3$ volatilization have a specific isotope fractionation factor (${\alpha}$) for each N process. Variation in the ${\delta}^{13}C$ of plants reflects the photosynthetic type of plant, which affects the isotope fractionation during photosynthesis. The ${\delta}^{13}C$ of C3 plant is significantly lower than, whereas the ${\delta}^{13}C$ of C4 plant is similar to that of the atmospheric $CO_2$. Variation in the isotope fractionation of carbon and nitrogen can be observed under different environmental conditions. The effect of environmental factors on the stomatal conductance and the carboxylation rate affects the carbon isotope fractionation during photosynthesis. Changes in the environmental factors such as temperature and salt concentration affect the nitrogen isotope fractionation during the N cycle processes; however, the mechanism of variation in the nitrogen isotope fractionation has not been studied as much as that in the carbon isotope fractionation. Isotope fractionation factors of carbon and nitrogen could be the integrated factors for interpreting the effects of the environmental factors on plants and soils.