• Title/Summary/Keyword: corrective action

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Developments in Hull Strength Monitoring (Developments in Hull Strength Monitoring)

  • P. A. Thomson;Ph. D BMT SeaTech Ltd.
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.2 no.1
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    • pp.143-143
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    • 1996
  • Recent Class requirements and IMO recommendations concerning Hull Strength Monitoring (HSM) have prompted an increasing number of shipowner to adopt monitoring systems on bulk carriers and tanker. Such systems are designed to give warning when stress levels and the frequency and magnitude of ship motions approach levels which require corrective action. When fitted these systems provide enhanced operational safety and efficiency. This paper describes a development beyond the standard BMT HSM system through the integration of stress, motion and radar-based sea state monitoring with powerful, on-board, artificial intelligence (AI) tools. The latter utilises conceptual clustering techniques as an aid to pattern recognition in stress, fatigue. motion and sea state data clusters. This, in turn, provides additional operational guidance for ship's staff. Feedback from applications of the standard BMT HSM and extended HSM systems on board the British Steel Bulk Shipping fleet is described.

Economic Design of a Process Monitoring Procedure for Dichotomous Performance Variable under 100% Inspection (이치형 성능변수를 이용한 전수검사 하에서의 공정감시절차의 경제적 설계)

  • Kwon, Hyuck-Moo
    • Journal of Korean Institute of Industrial Engineers
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    • v.24 no.3
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    • pp.359-365
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    • 1998
  • An economic process monitoring procedure is presented when the major quality characteristic of the item is dichotomous. Every item is inspected and decided whether it is conforming or not. If an item is found to be nonconforming, the previous number of the successive conforming items is compared with a predetermined number r to check the process for existence of any assignable cause of variation. A cost model is constructed on the basis of costs of inspection, illegal signal, undetected out-of-control state and corrective action. By minimizing the expected total cost per unit time, the optimal value of r is obtained. The effects of cost coefficients are studied numerically.

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Application of Reliability Growth Management for Construction Equipment Development Process (건설장비 개발과정에서 신뢰성성장관리 적용방법에 대한 연구)

  • So, Young-Kug;Jeon, Young-Rok;Ryu, Byeong-Jin
    • Journal of Applied Reliability
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    • v.13 no.3
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    • pp.175-190
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    • 2013
  • This study considers reliability growth management as the excellent method for construction equipment development with the effect on decreasing COPQ(Cost of Poor Quality Cost) of new products. MIL-HDBK-189A(1981) and RADC-TR-84-20(1984) standards provide a general concept of reliability growth management including to reliability growth test, models and FRACAS(Failure Reporting and Corrective Action System). There is no study how to apply reliability growth management to construction equipment(or machine) development. This paper propose the method to apply it to construction equipment development process from the reliability target setting for developing products to launching them at market. It is expecially showing how to set target reliability for new developing equipment and the development risk to reach the reliability target in detail.

Learning Assembly Strategies for Chamferless Parts (학습적 방법에 의한 챔퍼없는 부품의 조립에 관한 연구)

  • Ahn, D.S.;Kim, S.Y.;Cho, H.S.
    • Journal of the Korean Society for Precision Engineering
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    • v.10 no.3
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    • pp.175-181
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    • 1993
  • In this paper, a practical method to generate task strategies applicable to chamferless and high-precision assembly, is proposed. The difficulties in devising reliable assembly strategies result from various forms of uncertainty such as imperfect knowledge on the parts being assembled and functional limitations of the assembly devices. In approach to cope with these problems, the robot is provided with the capability of learning the corrective motion in response to the force signal trrough iterative task execution. The strategy is realized by adopting a learning algorithm and represented in a binary tree type database. To verify the effectiveness of the proposed algorithm, a series of simulations and experiments are carried out under assimilated real production environments. The results show that the sensory signal-to-robot action mapping can be acquired effectively and, consequently, the chamferless assembly can be performed successfully.

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A Study of Stress off City Gas Pipe Attached on the Bridge (교량에 부착된 도시가스 배관의 응력에 관한 연구)

  • Lee Su-Kyung;Lim Bong-Gwan
    • Journal of the Korean Institute of Gas
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    • v.10 no.3 s.32
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    • pp.20-26
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    • 2006
  • The survey team has conducted the on-the-site inspection of 53 bridges to which LNG gas pipelines are attached, to ascertain their level of safety, durability and any defect by adapting a method of computer data input process and precision analysis. In this way, we could estimate an effective corrective action on the defective gas pipelines found through this survey. Our survey team has analyzed carefully these 2 defective lines selectively out of 10 lines, which are considered to be most seriously weak. According to our elaborate analysis these two pipelines go over 70% of the set standard stress based on our Safety Manual Scale. We have taken corrective actions on these lines by repairing/replacing/obsolete damaged lines to ensure the distress of the bridges involved with the pipelines and could secure safety.

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The Koreans Apology Map: An Analysis of Apologies by Types during the Past 10 Years (한국인의 사과 지형: 지난 10년간 사과문의 조직 및 유형 별 분석)

  • Kim, Yung-Wook;Yang, Jung-Eun
    • Korean journal of communication and information
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    • v.59
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    • pp.180-210
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    • 2012
  • The purpose of the study was to analyze the apologies made in Korea for the past 10 years, and to diagnose how Koreans used crisis communication strategies. For the analysis, typology of crisis communication strategy was adopted from previous study as well as the new typology distinctively found in Korea. Also preferred crisis communication strategies were analyzed by crisis subject, by crisis type and by stage of crisis. Results showed that among the crisis communication strategies, apology and corrective action were the most used strategies, followed by bolstering and appealing to sympathy. Preferred crisis communication also differed by crisis subject, by crisis type and by stage of crisis. When the crisis subject were government or public institutions, when the locus of crisis responsibility was internal, and when the crisis was a controllable human/social crisis, the justification strategy was preferred. The results seemed to be related to the unique cultural characteristics of Koreans, especially to sense of Cheong and Chemyon. Indirect corrective action and transcendence were Chemyon-saving strategies while bolstering and appealing to sympathy were strategies appealing to Cheong. Future study should address the new typology of crisis communication strategy reflecting the cultural characteristic.

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Human Risk Assessment of a Contaminated Site Using Korean Risk-Based Corrective Action (K-RBCA) Software (한국형 소프트웨어를 이용한 유류.중금속 복합오염지역의 인체위해성평가 및 RBCA Tool Kit과의 비교분석)

  • Nam, Taek-Woo;Ryu, Hye-Rim;Kim, Young-Jin;Ko, Seok-Oh;Baek, Ki-Tae;Nam, Kyoung-Phile
    • Journal of Soil and Groundwater Environment
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    • v.16 no.1
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    • pp.32-41
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    • 2011
  • By using a newly developed Korean risk-based corrective action (K-RBCA) software (K-RBCA) and the RBCA Tool Kit, risk assessment was performed on a site that was contaminated with aromatic hydrocarbons and heavy metals. Eight chemicals including benzene, ethylbenzene, xylenes, naphthalene, benz(a) anthracene, benzo(b) fluoranthene, benzo(a) pyrene, and arsenic that exceeded the US EPA Soil Screening Level were chosen as the target pollutants. A conceptual site model was constructed based on the site-specific effective exposure pathways. According to the RBCA Tool Kit the carcinogenic risk of arsenic was larger than $10^{-6}$, which is the generally acceptable carcinogenic risk level. The K-RBCA estimated the same level of carcinogenic risk for arsenic. With the RBCA Tool Kit, the carcinogenic risk of benzo(a) pyrene was estimated to be about $1.3{\times}10^{-6}$. However, with the K-RBCA benzo(a) pyrene did not exhibit any risk. The inconsistency between the softwares was attributed to the different fundamental settings (i.e., medium division) between the two softwares. While the K-RBCA divides medium into surface soil, subsurface soil, and groundwater, the RBCA Tool Kit divides medium into only soil and groundwater. These differences lead to the different exposure pathways used by the two softwares. The K-RBCA considers the exposure pathways in surface soil and subsurface soil separately to estimate risk, however, the RBCA Tool Kit considers the surface soil and subsurface soil as one and uses the integrated exposure pathways to estimate risk. Thus the resulting risk is higher when the RBCA Tool Kit is used than when the K-RBCA is used. The results from this study show that there is no significant difference in the risks estimated by the two softwares, thus, it is reasonable to use the K-RBCA we developed in risk assessment of soil and groundwater. In addition, the present study demonstrates that the assessor should be familiar with the characteristics of a contaminated site and the assumptions used by a risk assessment software when carrying out risk assessment.

Development of a Posture Classification Scheme Reflecting the Effects of External Load and Motion Repetition (외부 부하, 동작 반복 효과가 반영된 자세 분류 체계의 개발)

  • Kee, Do-Hyung
    • Journal of the Ergonomics Society of Korea
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    • v.26 no.1
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    • pp.39-46
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    • 2007
  • The purpose of this study was to develop a comprehensive posture classification scheme considering the effects of external load and motion repetition as well as those of working posture. The scheme was developed based on a series of existing empirical studies dealing with postural classification scheme, effects of external load and motion repetition. Ranges of joint motions, external load and motion repetition were divided into the groups with the same degree of discomforts. Each group was assigned a numerical relative discomfort score of code on the basis of discomfort values for the neutral position of elbow flexion. The criteria for evaluating stress of working postures were proposed based on the four distinct action categories, in order to enable practitioners to apply appropriate corrective actions. The proposed scheme was compared with OWAS, RULA and REBA. The comparison revealed that while the proposed scheme and RULA showed similar results for the working postures with light external load and non-repetitive postures, the former overestimated postural load for postures with moderate or heavy external load and repetitive postures than the latter.

Applicability of NIOSH Lifting Equation to analysis of Workload for Patients Transferring (병원 환자 운반 업무의 작업 부하 분석에 NIOSH 들기 작업 공식의 적용 가능성)

  • Gi, Do-Hyeong
    • Journal of the Ergonomics Society of Korea
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    • v.25 no.2
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    • pp.43-50
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    • 2006
  • The purpose of this study was to investigate applicability of NIOSH lifting equation(NLE) to analysis of workload for patient transferring. In principle, the NLE is not applied to analyzing workload of patient transferring, because 1) the task is generally performed by two or more persons; 2) unlike ordinary objects, human body of patients is basically unstable load with their location of the center of mass significantly varying during lifting activity; and 3) the task is done in a restricted work space. This study was conducted through comparison of NIOSH lifting indexes(LIs) and L5/S1 compressive forces by 3DSSPP for patient transferring tasks performed by 2~6 persons. The results showed that LIs are linearly correlated with L5/S1 compressive forces with correlation coefficient of 0.92, which resulted in a significant simple linear regression equation for LIs and L5/S1 compressive forces. Consequently, it was concluded that the NLE is applicable to transferring patient only with slight modification. Based on the results, instead of 1.0 originally used by NIOSH, the LI of 1.5 was proposed as a gauge to estimate whether or not the task needs corrective action to reduce risk for developing lifting-related low back pain.