• Title/Summary/Keyword: target failure/safety level

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Problems and suggested improvement plans for occupational health service in Korea

  • Dongmug Kang
    • Annals of Occupational and Environmental Medicine
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    • v.35
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    • pp.10.1-10.10
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    • 2023
  • The purpose of this paper was to review the problems relating to Korea's occupational health services and suggest ways to improve them. Korea can be classified as a welfare state type of conservative corporatism partially interwoven with liberalism. While experiencing compressed economic growth, the economic sectors of developed (excess areas) and developing (deficient areas) countries are interwoven. Therefore, it is necessary to perfect conservative corporatism along with a complementary reinforcement of liberal contents and to apply a multilayered approach focusing on complementing the deficient areas. It is essential to form a national representative indicator related to occupational health, and a strategy for selection and concentration is needed. The proposed central indicator is the occupational health coverage rate (OHCR), which is the number of workers who have applied for mandatory occupational health services under the Occupational Safety and Health Act in the numerator with the total working population in the denominator. This paper proposes ways to raise the OHCR, which is currently at the level of 25%-40%, to 70%-80%, which is the level of Japan, Germany, and France. To achieve this target, it is necessary to focus on small businesses and vulnerable workers. This is an area of market failure and requires the active input of community-oriented public resources. For access to larger workplaces, the marketability of services should be strengthened and personal intervention using digital health resources should be actively attempted. Taking a national perspective, work environment improvement committees with tripartite (labor, management, and government) participation for improvement of the working environment need to be established at the center and in the regions. Through this, prevention funds linked to industrial accident compensation and prevention could be used efficiently. A national chemical substance management system must be established to monitor the health of workers and the general public.

An Investigation into differences between codes for the Moment Strength of Deck Plates (데크플레이트의 휨 강도에 관한 기준 비교 연구)

  • Shin, Tae Song
    • Journal of Korean Society of Steel Construction
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    • v.15 no.1
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    • pp.25-31
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    • 2003
  • This research aimed to experimentally and theoretically investigate the moment strength of deck plates. A moment experiment was carried out using a full-scale 14 specimen. To prevent local buckling, the point load was applied at 1/4 points. After the experiment, theoretical analysis was conducted and the differences between various codes were identified. The experimental results were compared with AISI (the American Iron and Steel Institute), EC (Euro Code) 3, and KS (Korea Standard) codes. Analysis results are summarized as follows: (1) the failure mode was influenced by local buckling at the midpoint of the beam and/or at the intermediate loading point: (2) if yielding first occurred at the tension side, the moment strength would increase as the plastic reservation of the tension zone acted: (3) the experimental results were closest to the EC3 codes in which the partial plastic reservation was considered; (4) statistical evaluation based on the EC3 Annex Z showed that the partial resistance safety coefficient calculated applying to the EC3 formula, $^{\circ}{_M}$, was placed within 1.1 which was the target value of EC3 code; and (5) the analytical power of AISI and KS codeswere expected to improve into the level of EC3 codes if the concept of plastic reservation of the tension side would be introduced to them.

Evaluation of Service Life in RC Column under Chloride Attack through Field Investigation: Deterministic and Probabilistic Approaches (염해 실태조사를 통한 철근 콘크리트 교각의 내구수명 평가 - 결정론적 및 확률론적 해석방법)

  • Kwon, Seung-Jun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.19 no.5
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    • pp.67-74
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    • 2015
  • RC (Reinforced Concrete) structures are considered as cost-benefit and durable however performances of structural safety and durability are degraded due to steel corrosion. Service life in RC structure is differently evaluated due to different local environmental conditions even if it is exposed to the same chloride attack. In the paper, 25 concrete cores from field investigation are obtained from 4 RC columns with duration of 3.5~4.5 years exposed to sea water. Through total chloride content measurement, surface chloride contents and apparent diffusion coefficients are evaluated. Service life of the target structure is estimated through deterministic method based on Fick's $2^{nd}$ Law and probabilistic method based on durability failure probability, respectively. Probability method is evaluated to be more conservative and relatively decreased service life is evaluated in tidal zone and splash zone over 40.0 m. Chloride penetration behavior with coring location from sea level and the present limitations of durability design method are investigated in the paper.

Seismic Performance Evaluation of Dry Precast Concrete Beam-Column Connections With Intermediate Moment Frame Details (중간모멘트골조 상세를 갖는 건식 프리캐스트 콘크리트 보-기둥 접합부의 내진성능평가)

  • Kim, Seon Hoon;Cho, Jong;Oh, Hyo Keun;Choi, Seok Dong;Yeo, Un Yong;Lee, Deuck Hang
    • Journal of the Earthquake Engineering Society of Korea
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    • v.27 no.3
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    • pp.129-137
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    • 2023
  • This study presents a dry precast concrete (PC) beam-column connection, and its target seismic performance level is set to be emulative to the reinforced concrete (RC) intermediate moment resisting frame system specified in ACI 318 and ASCE 7. The key features include self-sustaining ability during construction with the dry mechanical splicing method, enabling emulative connection performances and better constructability. Test specimens with code-compliant seismic details were fabricated and tested under reversed cyclic loading, which included a PC beam-column connection specimen with dry connections and an RC control specimen. The test results showed that all the specimens failed in a similar failure mode due to plastic deformations in beam members, while the hysteretic response curve of the PC specimen showed comparable and emulative performances compared to the RC specimen. Seismic performance evaluation was quantitatively addressed, and on this basis, it confirmed that the presented system can fully satisfy all the required performance for the intermediate RC moment resisting frame.

A Study on the Concept of a Ship Predictive Maintenance Model Reflection Ship Operation Characteristics (선박 운항 특성을 반영한 선박 예지 정비 모델 개념 제안)

  • Youn, Ik-Hyun;Park, Jinkyu;Oh, Jungmo
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.27 no.1
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    • pp.53-59
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    • 2021
  • The marine transport industry generally applies new technologies later than other transport industries, such as airways and railways. Vessels require efficient operation, and their performance and lifespan depend on the level of maintenance and management. Many studies have shown that corrective maintenance (CM) and time-based maintenance (TBM) have restrictions with respect to enabling efficient maintenance of workload and cost to improve operational efficiency. Predictive maintenance (PdM) is an advanced technology that allows monitoring the condition and performance of a target machine to predict its time of failure and helps maintain the key machinery in optimal working conditions at all times. This study presents the development of a marine predictive maintenance (MPdM; maritime predictive maintenance) method based on applying PdM to the marine environment. The MPdM scheme is designed by considering the special environment of the marine transport industry and the extreme marine conditions. Further, results of the study elaborates upon the concept of MPdM and its necessity to advancing marine transportation in the future.

Implementation of Responsive Web-based Vessel Auxiliary Equipment and Pipe Condition Diagnosis Monitoring System (반응형 웹 기반 선박 보조기기 및 배관 상태 진단 모니터링 시스템 구현)

  • Sun-Ho, Park;Woo-Geun, Choi;Kyung-Yeol, Choi;Sang-Hyuk, Kwon
    • Journal of Navigation and Port Research
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    • v.46 no.6
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    • pp.562-569
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    • 2022
  • The alarm monitoring technology applied to existing operating ships manages data items such as temperature and pressure with AMS (Alarm Monitoring System) and provides an alarm to the crew should these sensing data exceed the normal level range. In addition, the maintenance of existing ships follows the Planned Maintenance System (PMS). whereby the sensing data measured from the equipment is monitored and if it surpasses the set range, maintenance is performed through an alarm, or the corresponding part is replaced in advance after being used for a certain period of time regardless of whether the target device has a malfunction or not. To secure the reliability and operational safety of ship engine operation, it is necessary to enable advanced diagnosis and prediction based on real-time condition monitoring data. To do so, comprehensive measurement of actual ship data, creation of a database, and implementation of a condition diagnosis monitoring system for condition-based predictive maintenance of auxiliary equipment and piping must take place. Furthermore, the system should enable management of auxiliary equipment and piping status information based on a responsive web, and be optimized for screen and resolution so that it can be accessed and used by various mobile devices such as smartphones as well as for viewing on a PC on board. This update cost is low, and the management method is easy. In this paper, we propose CBM (Condition Based Management) technology, for autonomous ships. This core technology is used to identify abnormal phenomena through state diagnosis and monitoring of pumps and purifiers among ship auxiliary equipment, and seawater and steam pipes among pipes. It is intended to provide performance diagnosis and failure prediction of ship auxiliary equipment and piping for convergence analysis, and to support preventive maintenance decision-making.