• Title/Summary/Keyword: Safety lines

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Protecting electronic equipment against lightning surge (옥외용 전자장비의 낙뢰 서지 대책)

  • 임순재;이주광;이완규;최만용
    • Journal of the Korean Society of Safety
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    • v.12 no.1
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    • pp.29-36
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    • 1997
  • Precision electronic equipments for outdoor use are composed of sophisticated microcircuits that are extremely vulnerable to lightning-caused voltage spike. This transient voltage spike may cause upset, latent failure or Interference on electronic equipments. In order to develop efficient lightning protection measures on AC power lines of a road traffic controller as a electronic equipment for outdoor use, experimental surge immunity tests were conducted according to IEC standard 801-5. The combination of gas tube arrester and metal-oxide varistor was installed at the input of AC power lines and the silicon avalanche suppressor installed at the output of DC power supply for the lightning protection measures.

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Line Balancing in the Multiple U-Type Lines Using Genetic Algorithms (유전알고리듬을 이용한 복수 U라인의 라인밸런싱)

  • 김동묵;김용주
    • Proceedings of the Safety Management and Science Conference
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    • 1999.11a
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    • pp.501-514
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    • 1999
  • Multiple U-typed production lines are increasingly accepted in modern manufacturing system for the flexibility to adjust to changes in demand. This paper considers multiple U line balancing with the objective of minimizing cycle time considering of moving time of workforce given the number of workstation. Like the traditional line balancing problem this problem is NP-hard. In this paper, we show how genetic algorithm can be used to solve multiple U line balancing. For this, an encoding and a decoding method suitable to the problem are presented. Proper genetic operators are also employed. Extensive computational experiments are carried out to show the performance of the proposed algorithm. The computational results show that the algorithm is promising in solution quality.

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Sequencing Problem to Keep a Constant Rate of Part Usage In Mixed Model Assembly Lines : A Genetic Algorithm Approach (혼합모델 조립라인에서 부품사용의 일정률 유지를 위한 생산순서 결정 : 유전알고리즘 적용)

  • Hyun, Chul-Ju
    • Journal of the Korea Safety Management & Science
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    • v.9 no.4
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    • pp.129-136
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    • 2007
  • This paper considers the sequencing of products in mixed model assembly lines under Just-In-Time (JIT) systems. Under JIT systems, the most important goal for the sequencing problem is to keep a constant rate of usage every part used by the systems. The sequencing problem is solved using Genetic Algorithm Genetic Algorithm is a heuristic method which can provide a near optimal solution in real time. The performance of proposed technique is compared with existing heuristic methods in terms of solution quality. Various examples are presented and experimental results are reported to demonstrate the efficiency of the technique.

Sequencing to keep a constant rate of part usage in car assembly lines (자동차 조립라인에서 부품사용의 일정율 유지를 위한 투입순서 결정)

  • 현철주
    • Journal of the Korea Safety Management & Science
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    • v.4 no.3
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    • pp.95-105
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    • 2002
  • This paper considers the sequencing of products in car assembly lines under Just-In-Time systems. Under Just-In-Time systems, the most important goal for the sequencing problem is to keep a constant rate of usage every part used by the systems. In this paper, tabu search technique for this problem is proposed. Tabu search is a heuristic method which can provide a near optimal solution in real time. The performance of proposed technique is compared with existing heuristic methods in terms of solution quality and computation time. Various examples are presented and experimental results are reported to demonstrate the efficiency of the technique.

Virus-resistant and susceptible transgenic Nicotiana benthamiana plants expressing coat protein gene of Zochini green mottle mosaic virus for LMO safety assessment

  • Park, M.H.;B.E. Min;K.H. Ryu
    • Proceedings of the Korean Society of Plant Pathology Conference
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    • 2003.10a
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    • pp.146.1-146
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    • 2003
  • Transgenic Nicotiana benthmiana plants harboring and expressing coat protein (CP) gene of Zucchini green mottle mosaic virus (ZGMMV) were generated for both virus-resistant screening and complementation analysis of related viruses and environmental safety assessment (SA) of living modified organism (LMO) purposes. Transformation of leaf disc of N. benthamiana was performed using Agrobacterium-mediated method and the pZGCPPGA748 containing the ZGMMV CP and NPTII genes. Two kinds of transgenic homozygous groups, virus-resistant and -susceptible lines, were obtained by screening of challenging homologous virus for T1 generations. Complementation of CP-deficient related virus was analyzed using the susceptible line of ZGMMV. These two pathologically different lines can be useful for host-virus interactions and LMO environmental SA.

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Investigation of Effective Maintenance System for the Infra on the Conventional Line Prepared for the Tilting Train Service (틸팅열차 상용화대비 기존선 인프라시스템의 효율적 유지보수체계 검토)

  • Yoo, Keun-Su;Lee, Chang-Hun;An, Gang-Yell;Kim, Joung-Tea
    • Proceedings of the KSR Conference
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    • 2008.11b
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    • pp.79-87
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    • 2008
  • The major objective of this study is to investigate the effective maintenance system for the infrastructure on the conventional lines in which the tilting train runs. In order to the speed-up of conventional lines that have many curve lines, there needs a improvement construction of substructure such as the straight or double track work and so on. But in this case, it needs to have a plenty of the cost and the period. Therefore, the tilting train which provides the high-speed service effectively in curve tracks was developed. Besides, the efficiency prediction and the linear fitness of the existing conventional lines for a tiling train service were examined on the preceding study which was the development of track system innovation technology for speed-up of them. So, in this paper we propose the more effective maintenance method than the existing it in order to securing the high reliability and safety classified by the infrastructure, in analyzing foreign materials and the maintenance as well as the inspection cycle concerning domestic infrastructures of the track and the catenary etc. on the railway. And we look forward to playing a decisive role as reference material for the effective improvement of the existing maintenance about the infra on the conventional lines for the commercial service of the tilting train.

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An Assessment of Notice Exposure by Job and Dosimeter Parameters Setting in Automobile Press Factory (자동차 프레스 공정에 있어서 직무 및 누적소음기 설정치 차이에 따른 작업자의 소음노출 평가)

  • Jeong, Jee Yeon;Park, Seunghyun;Yi, GwangYong;Lee, Naroo;You, Ki Ho;Park, Junsun;Chung, Ho Keun
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.11 no.3
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    • pp.190-197
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    • 2001
  • Noise-induced hearing loss(NIHL) was the highest rate (43.5%~58.5% from 1996 to 1998) of positive findings through specific medical program in Korea. There were much more NIHL at workers of automobile manufacturing factories than other manufacturing factories. The specific aim of the present study was to determine the noise exposure of automobile press lines, according to their job titles, press line types(auto, semiauto), dosimeter parameters setting. There were a total 11 press lines sampled at a automobile manufacturing company. Among those press lines, 10 press lines were autolines with acoustic enclosure, one semiauto press line was no aucostic enclosure Noise exposure data were sampled for an work shift using noise dosimeter, which recorded both time-weighted average(TWA) and 1-min average. The mean OSHA TWA(Korea TWA with threshold 90) was $80.7dB(A){\pm}4.7dB(A)$ for leader, $82.8dB(A{\pm}4.5dB(A)$ for pallette man, $76.7dB(A){\pm}4.3dB(A)$ for press operators, $76.6dB(A){\pm}5.6dB(A)$ for crane operators, $77.1dB(A){\pm}2.8dB(A)$ for forklift drivers, whereas the mean NIOSH TWA was $88.9dB(A){\pm}1.7dB(A)$ for leader, $89.6dB(A){\pm}2.1dB(A)$ for pallette man, $86.7dB(A){\pm}1.8dB(A)$ for press operators, $88.5dB(A){\pm}2.0dB(A)$ for crane operators, $87.7dB(A){\pm}1.0dB(A)$ for forklift drivers. While L10 for NIOSH TWA samples was 84.8 dB(A) ~ 87.3 dB(A), L10 for OSHA TWA samples was 69.5 dB(A) ~ 77.4 dB(A). L10 means that the TWA for 90% of the samples exceeded L10. Among OSHA TWA(Korea TWA with threshold 90) samples for pallette man, 7.7 % exceeded 90 dB(A), the OSHA permissible exposure level, but OSHA TWA samples for the other job titles didn't. Among NIOSH TWA samples, the samples over 85 dB(A), the NIOSH recommended exposure limit, was 100% (leaders), 83.3 %(operators), 97.4%(palletteman), 100%(forklift drivers), 91.7 %(crane operator). The results of One-way random effects analysis of variance models shows that the difference between job titles was significant by OSHA TWA(p<0.05), but not significant by NIOSH TWA(p>0.05). NIOSH TWA samples were significantly higher than OSHA TWA samples(P<0.05). Regression analysis was used to obtain relationships between OSHA TWA samples and NIOSH TWA samples. In this case the coefficient of determination = 0.90, which shows the high degree association between two methods. Regression equation, NIOSH TWA = 0.552 * OSHA TWA + 42.13 dB(A), shows that if OSHA TWA is known, NIOSH TWA can be predicted by the equation. The mean TWA difference between threshold 80 dBA and 90 dBA was significant(p<0.01). While the TWA noise exposures were 7.7% above the Korea(OSHA) PEL, they were more than 83.3% over NIOSH REL. Automobile workers were exposed to noise level that could be potentially damaging to their hearing. It found that there is approximately 25% excess risk of hearing loss even if a worker is protected to the PEL in according to NIOSH study.

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Qualitative Analysis on the Results of the Integrated Railway Safety R&D Project (철도종합안전기술개발사업 성과 분석)

  • Kim, Sang-Ahm;Cho, Yun-Ok
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.2952-2960
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    • 2011
  • The railway safety in Koreaisthreatenedduetotherestructuring of the railway industries, introduction of the Korea Train eXpress (KTX) and electrification of the conventional lines. Many technical backgrounds are required to control railway accidents as low as reasonably practicable, such as a railway safety act, safety standards, and safety assessment infrastructures. Korean government and the Korea Railroad Research Institute (KRRI) are conducting an integrated R&D program for improvement of the railway safety, where the target is to reduce the accident fatalities by half. The program is composed of three parts; the safety system engineering and the program management, the establishment of a safety management system, and the development of techniques for assessing and preventing major railway accidents. Details of the research programs are explained in this paper, where risk is used as the major control measure.

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Research for the Mainly Cause of Safety-Management Sharp-type of Semiconductor Industry (To Center with Corporate Company) (반도체 산업의 안전관리 형태별에 따른 원인에 관한 연구 (협력업체 중심(中心)으로))

  • Yoon, Yong-Gu
    • Proceedings of the Safety Management and Science Conference
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    • 2008.04a
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    • pp.19-33
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    • 2008
  • The study on semiconductor industrial accident in korea has been focused on frequencies of each type, employee, characteristics, cause and un-safety condition, behaviour and so on. Those attributes of semiconductor industrial accidents were usually analyzed independently, so that it was hard to provides a well-process and systematic guide lines for efficient safety management. There fore, there were a few studies based on comprehensive survey in terms of sharp-type of safe management. The questionnaire survey carried out for the workers(284) who were responsible for safety management in to center with corporate company with semiconductor industry the factor analysis showed that there were three factor of safety management. They were 1) Investment and operation and management for accident prevention, 2) Unsafe, safety management 3) General human error and behavior the industries of respondents were correlative with three group. Three Groups showed a statistically significant differences on the number of cases. Actually, the group with the larger investment and the better unsafe cause, human error a of accident prevention had a smaller cause of accident cases.

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The Evaluation of the Egress Performance in the Buildings Installed with Luminous Egress Guide-lines (건축물내 자체발광식 피난유도선 설치에 따른 피난성능 평가)

  • Park, Yong-Hwan;Kim, Beom-Gyu;Lim, Chae-Hyun
    • Fire Science and Engineering
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    • v.25 no.6
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    • pp.120-126
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    • 2011
  • Recently luminous egress guide-lines are introduced for the fire safety of residents in the multi-use buildings such as Gosiwon. Little literature, however, on the quantitative and qualitative estimation for the egress performance of the luminous egress guide-lines can be found. This study carried out experimental investigations to evaluate the egress performance of the existing egress guide-lights and new luminous egress guide-lines. The results showed that both luminous egress guide-lines and egress guide-light satisfied the basic performance of KFI requirements. Under the 7 % smoke transmittance, however, luminous egress guide-lines showed 3 times longer visibility and less evacuation time than egress guide-lights. The evacuation density and smoke transmittance have significant effect on the evacuation time increase without the luminous egress guide-lines, however little effect with the installation.