• Proceedings of the Safety Management and Science Conference
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• 2007.11a
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• pp.275-298
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• 2007

Recently, all kind of 21C-typed electronic goods show the tendency of hightechnology and digital convergence rapidly. Also, failure mechanism which differs from original goods concept presents. Today, failure mechanism which differs from one that was happened by restricted harmful environment material before adapted the raw of environment material is changing the paradigm of reliability engineering. Thus, when applied the environment matter of original and secondary material at the electronic goods were removed, reliability assessment method and prediction stay into low level. This study suggests as solution to overcome these phenomenon. The study on the management method of environmental restriction substances which is recognized as important element in the reliability assessment about environment material of electronic goods and the study on reliability assessment method of PWB without environment material are progressed.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.111-112
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• 2008

Although two types of uncertainty such as randomness and fuzziness simultaneously exist in power systems, yet they have been treated as distinct fields to evaluate the power system reliability. Thus, this paper presents a reliability assessment method based on a combined concept of fuzzy and probability. To reflect the two-fold uncertainty, a modified load duration curve(MLDC) is proposed using the probability distribution of historical load data in which a fuzzy model for the peak load forecast is embedded. IEEE RTS system was used to demonstrate the usefulness and applicability of the proposed method, and the reliability indices were obtained using the proposed MLDC. The results show a wider insight into impact of load fuzziness on uncertainties of reliability indices for power systems.

• Journal of Korean Society of Steel Construction
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• v.14 no.5 s.60
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• pp.627-639
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• 2002

Bridge construction is almost complete in many countries. Thus, the government and highway agencies change their focus from constructing to maintaining. Effectively maintaining bridges require predicting their lifespan using a system reliability viewpoint. Likewise, maintenance models based on the system reliability concept should be developed. Thus, this study developed maintenance models for preventive maintenance and essential maintenance using system reliability and lifetime distributions. The optimal maintenance strategy for an existing bridge was obtained using the developed maintenance models.

• Proceedings of the KSR Conference
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• 2001.05a
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• pp.319-326
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• 2001

Railway signaling safety system organizes equipments and facilities of railway, increases transport efficiency and assures safe operation of railway. In the early days of signaling system railway managers made sure of safety by using relay logic technology based on fail-safe concept. But the development result of computer and science having been introduced to railway industry, railway signaling equipments begin to be operated through micro electronic control system. Accordingly high speed and high density operation of train became possible. Software reliability and safety technology that controls important systems of railway was highlighted. In the middle of 1990s the standard or guideline of railway reliability and safety were studied and established, and are being reviewing in Europe, Japan etc. Our reliability and safety technology have depended largely on foreign countries. In this study we performed a basic study about the reliability of software that controls the railway signaling system.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.30 no.1
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• pp.1-7
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• 2007

This paper addresses a the maintenance system based on the concept of RAMS (Reliability, Availability, Maintenance, Safety) for the effective maintenance of the urban transit. A systematic approach for developing a cost-effective maintenance strategy based on the component reliability of the system in question is performed according to the following steps : definition of function, functional failures of the systems, construction of RBD (Reliability Block Diagram), and the calculation of reliability indices. The developed preventive maintenance system generates maintenance plan and repair request based on the analysed RAMS data of components and maintenance experience.

• Journal of The Korean Association For Science Education
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• v.22 no.2
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• pp.398-409
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• 2002

The purpose of this study was to investigate the validity, reliability and practicality of a concept map as an assessment tool in the context of biology concept learning. Forty undergraduate students participated in concept mapping, and the maps were scored by preservice science teachers, using one of three different scoring methods, that is, concept map scoring methods developed by Burry-Stock, Novak & Gowin and McClure & Bell. Two scorers were assigned to each scoring method. As far as the validity of the assessment methods was concerned, two of the three methods were found to be very valid, while Burry-Stock's scoring method was shown little valid. As far as the internal consistency of the methods was concerned, considerably high consistencies were shown between every pair of scorers, judging from high correlation coefficients between the pair of scorers for each scoring method. It took from 1.13 minutes to 3.70 minutes to assess a map at the average. It showed that concept mapping could be used in school classrooms with the limited resources of time and people. These findings suggest that the concept mapping can be an appropriate tool for assessing biology concept understandings.

• Women's Health Nursing
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• v.7 no.2
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• pp.131-140
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• 2001

As one of the important purpose of the concept is mutual communication, the concept should be defined clearly concerned concept, differed from others concept, identified intersubjectiveness, and could communicated readily and easily between researcher and practitioner through concept analysis. By analysing and synthesizing the concept of "Sanhujori" according to concept analysis of Walker and Avant. The author has tried to establish the term "Sanhujori" which gas been widly used from the past till now in Korea as a scholarly terminoloy and to develop a tool for the assessment of "Sanhujori". The conceptional attributes of the "Sanhujori" were figured out such as (1) hospitality; (2) physical and emotional recovery; (3) caring; (4) maternal role attainment. The assessment tool for the "Sanhujori" was constituted of 40 items of the conceptional attributes and tested on the 30 mothers more than 8 weeks of postpartal period. The reliability was that Cronbach's $\alpha$ is .9238.

• Journal of the military operations research society of Korea
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• v.8 no.1
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• pp.53-70
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• 1982

This thesis develops a more realistic and applicable new set covering model that is adjusted and supplied by the existing set covering models, and induces an algorithm for solving the new set covering model, and applies the new model and the algorithm to an actual set covering problems. The new set covering model introduces a probabilistic covering aistance ($0{\eqslantless}p{\eqslantless}1$)or time($0{\eqslantless}p{\eqslantless}1$) instead of a deterministic covering distance(0 or 1) or time (0 or 1) of the existing set covering model. The existing set covering model has not considered the merit of the overcover of customers. But this new set covering model leads a concept of this overcover to a concept of the parallel system reliability. The algorithm has been programmed on the UNIVAC 9030 for solving large-scale covering problems. An application of the new set covering model is presented in order to determine the locations of the air surveillance radars as a set covering problem for a case-study.

• Tribology and Lubricants
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• v.19 no.1
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• pp.36-42
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• 2003

Nowadays the importance of equipment reliability and efficiency is increasing and the concept of Total Fluid Management is introduced to make production cost down and improve equipment reliability. In this paper, basic survey on the current status of lubricants application and equipment maintenance is made. Lubrication point of the factory was 233 and 60 percent of the point was lubricated by hydraulic oils. Lubricants used at 87 points were different from those of original equipment manufacturers' recommendation. And 40 percent of the points are heavily contaminated. Exchange of oils, use of filter, computerization and so on were recommended. And introduction of Total Fluid Management concept is required.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1989.10a
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• pp.19-24
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• 1989

The current load combination criteria for design of nuclear power plant structures are not based on the probability-based design concept but rely on the conventional design concept. In this paper, a load combination criteria for design of NPP coin-tainment structures are proposed based on a FEM-based random vibration analysis. More accurate reliability analyses under various dynamic loads such as earthquake loads were made possible by incorporating the FEM and random vibration theory, which is different from the conventional reliability analysis method. In this paper, the load factors for the design of NPP structures in Korea are proposed by considering appropriate fond combination criteria for design.