• Title/Summary/Keyword: Useful life

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A risk-based framework for design of concrete structures against earthquake

  • Hassani, Mohammadhassan;Behnam, Behrouz;Maknoon, Reza
    • Computers and Concrete
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    • v.25 no.2
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    • pp.167-179
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    • 2020
  • Optimal design of structures against earthquake loads is often limited to reduce initial construction costs, while the cost induced to structures during their useful life may be several times greater than the initial costs. Therefore, it is necessary to consider the indirect costs due to earthquakes in the design process. In this research, an integrated methodology for calculating life cycle cost (LCC) of moment-resisting concrete frames is presented. Increasing seismic safety of structures and reducing human casualties can play an important role in determining the optimal design. Costs incurred for structures are added to the costs of construction, including the costs of reconstruction, financial losses due to the time spent on reconstruction, interruption in building functionality, the value of people's life or disability, and content loss are a major part of the future costs. In this research, fifty years of useful life of structures from the beginning of the construction is considered as the life cycle. These costs should be considered as factors of calculating indirect costs of a structure. The results of this work represent the life cycle cost of a 4 story, 7 story, and 10 story moment-resisting concrete frame by details. This methodology is developed based on the economic conditions of Iran in 2016 and for the case of Tehran city.

Useful Image Back-projection Properties in Cameras under Planar and Vertical Motion (평면 및 수직 운동하는 카메라에서 유용한 영상 역투영 속성들)

  • Kim, Minhwan;Byun, Sungmin
    • Journal of Korea Multimedia Society
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    • v.25 no.7
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    • pp.912-921
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    • 2022
  • Autonomous vehicles equipped with cameras, such as robots, fork lifts, or cars, can be found frequently in industry sites or usual life. Those cameras show planar motion because the vehicles usually move on a plane. Sometimes the cameras in fork lifts moves vertically. The cameras under planar and vertical motion provides useful properties for horizontal or vertical lines that can be found easily and frequently in our daily life. In this paper, some useful back-projection properties are suggested, which can be applied to horizontal or vertical line images captured by a camera under planar and vertical motion. The line images are back-projected onto a virtual plane that is parallel to the planar motion plane and has the same orientation at the camera coordinate system regardless of camera motion. The back-projected lines on the virtual plane provide useful information for the world lines corresponding to the back-projected lines, such as line direction, angle between two horizontal lines, length ratio of two horizontal lines, and vertical line direction. Through experiments with simple plane polygons, we found that the back-projection properties were useful for estimating correctly the direction and the angle for horizontal and vertical lines.

Survey of the Life Expectancy Management of Fire Products (소방용품 내용연수 관리실태 조사 분석)

  • Park, In-Seon;Baek, Chang Sun
    • Fire Science and Engineering
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    • v.30 no.2
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    • pp.133-140
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    • 2016
  • Currently, the maintenance of fire products at the site of fire-fighting property are presumably carried out by a fireand/or self. On the other hand, of the special fire-fighting property, only 3.4% of them are the target for a comprehensive precision inspection, which is performed by fire protection management firms. Aging fire products for the rest of special fire-fighting property are absolutely beyond any inspection and reliability verification. This is also true with respect to general households. In this report, the current practice of fire products' useful life management at the site of fire-fighting property were studied. For this study, 32 items of fire products were identified. For the sample data, public institutions and 17 cities and provinces were classified into 18 groups, from which 30 sample targets for each group were determined. Of these targets 422 samples were recovered, based on which this study for establishing a useful 'Management Control System of the Fire Products and its Useful Life' was conducted.

A Study on the "Praxis" which are Perceived by Elementary Students on Practical Arts Education (초등학생들의 생활과 연계된 실과교과의 실천성 연구)

  • Byun, Hyo-Jun;Lee, Ki-Young;Lee, Soo-Hee
    • Journal of the Korean Home Economics Association
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    • v.47 no.8
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    • pp.71-85
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    • 2009
  • The purpose of this study is to find out the practical problems that 6th grade students are facing, how they perceive Practical Arts education and the praxis of Practical Arts education relating to the problems, and whether the content of Practical Arts curriculum is useful for solving practical problems of 6th grade students. The data used in this study are collected from questionnaires and include in-depth interviews in order to make up for the quantitative research. The major findings of this study were summarized as follows. 1. Elementary school students regarded Practical Arts education as the subject matter through which they learn skills of life. They thought it is useful to their present and future life and to nurture environment-friendly attitude. Furthermore, elementary school students perceive that the meaning of practice in Practical Arts education lies not in praxis as practical action, but in just practice as technical action. 2. According to the survey based on their perception and their practical problems, 66.9% of students answered the learning content of Practical Arts education is not useful in solving their problems. And only 33.4% of students answered the learning content of Practical Arts education is useful in solving their problems. Negative view was predominant among elementary school students. And the Practical Arts curriculum does not reflect much of the practical problems that 6th grade students face. Through these results, Practical Arts education turns out to be hardly related with students' life, though it is the subject matter of students' real life.

Molecular Characterization and Expression Analysis of Adrenergic Receptor Beta 2 (ADRB2) Gene before and after Exercise in the Horse

  • Cho, Hyun-Woo;Shin, Sangsu;Song, Ki-Duk;Park, Jeong-Woong;Choi, Jae-Young;Lee, Hak-Kyo;Cho, Byung-Wook
    • Asian-Australasian Journal of Animal Sciences
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    • v.28 no.5
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    • pp.686-690
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    • 2015
  • The adrenergic receptor beta 2 (ADRB2) plays a role in various physiological responses of the muscle to exercise, such as contraction and relaxation. Given its important role in muscle function, we investigated the structure of the horse ADRB2 gene and its expression pattern after exercise to determine if it can serve as a putative biomarker for recovery. Evolutionary analyses using synonymous and non-synonymous mutation ratios, were compared with other species (human, chimpanzee, mouse, rat, cow, pig, chicken, dog, and cat), and revealed the occurrence of positive selection in the horse ADRB2 gene. In addition, expression analyses by quantitative polymerase chain reaction exhibited ubiquitous distribution of horse ADRB2 in various tissues including lung, skeletal muscle, kidney, thyroid, appendix, colon, spinal cord and heart, with the highest expression observed in the lung. The expression of ADRB2 in skeletal muscle was significantly up-regulated about four folds 30 minutes post-exercise compared to pre-exercise. The expression level of ADRB2 in leukocytes, which could be collected with convenience compared with other tissues in horse, increased until 60 min after exercise but decreased afterward until 120 min, suggesting the ADRB2 expression levels in leukocytes could be a useful biomarker to check the early recovery status of horse after exercise. In conclusion, we identified horse ADRB2 gene and analyzed expression profiles in various tissues. Additionally, analysis of ADBR2 gene expression in leukocytes could be a useful biomarker useful for evaluation of early recovery status after exercise in racing horses.

A Study on Fatigue Life Assessment Procedure for a Container Crane (컨테이너 크레인의 피로수명 평가 방법에 관한 연구)

  • 정동관;윤기봉
    • Journal of the Korean Society of Safety
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    • v.14 no.2
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    • pp.11-18
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    • 1999
  • Proper fatigue life prediction procedures are needed for mechanical structures which requires high durability and reliability. In this paper, a fatigue life prediction procedure has been developed for predicting fatigue life of moving structure under variable loadings. The developed procedure was efficiently applied for a fatigue life calculation of a container crane. Especially, the procedure is useful for safety assessment by computer simulation. A computer program was developed for fatigue life assessment by adopting the forementioned procedure.

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State of the Art in Life Assessment for High Temperature Components Using Replication Method (표면복제기법을 이용한 고온 설비의 수명평가 현황과 적용사례)

  • Kim, Duck-Hee;Choi, Hyun-Sun
    • Journal of the Korean Society for Nondestructive Testing
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    • v.30 no.5
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    • pp.489-496
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    • 2010
  • The power generation and chemical industry have been subjected to further material degradation with long term operations and need to predict the remaining service life of components, such as reformer tube and steam turbine rotor, that have operated at elevated temperatures. As a non-destructive technique, replication method with reliable metallurgical life and microstructural soundness assessment has been recognized with strongly useful method until now. Developments of this method have variously accomplished by new quantitative approach, such as carbide analysis, with A-parameter and grain deformation method. An overview of replication, some new techniques for material degradation and life assessment were introduced in this paper. Also, on-site applications and its reasonableness were described. As a result of having analyzed microstructure by replication method, carbide approach was quantitatively useful to life assessment.

Life Cycle Cost Analysis of Main Conversion System in 8200 Series Electric Locomotive (8200호대 전기기관차 주변환장치 LCC 분석)

  • Kim, Wan-il;Lee, Kye-Seung;Choi, Jong-Rok;Kim, Jae-Moon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.12
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    • pp.1830-1835
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    • 2017
  • 8200 Series Electric Locomotives are mostly imported from overseas due to aging and uncertainty of source technology, and it's the maintenance cost is increasing. We are analyzed life cycle costs based on international standards such as IEC 60300-3-3 and IEC62278. The main conversion system of the 8200 series electric locomotive is closely related to vehicle operation and is one of the subsystems requiring frequent maintenance. In this paper, the life cycle cost of the main conversion unit in 8200 series electric locomotive is analyzed based on the maintenance manual. As a result of analysis, maintenance cost of GTO module and control device is relatively high, and it is confirmed that the cost increases according to the useful life.