• 산업공학
• /
• 제25권4호
• /
• pp.405-415
• /
• 2012

The reliability performance measures for low and high or continuous demand modes of operation of safety instrumented systems(SISs) are examined and compared by analyzing the official definitions in IEC 61508 standard. This paper also presents a status of common cause factor(CCF) models used in IEC 61508 and problems relating CCF modelling are discussed and ideas to solve these ones are suggested. An example with mixed M-out-of-N architecture is carried out to illustrate the proposed methods.

• 한국안전학회지
• /
• 제37권6호
• /
• pp.71-80
• /
• 2022

Since the 2000s, the demand for private demolition works has been gradually increasing as the apartment housing market has been led by redevelopment and reconstruction. In the case of the military, the Ministry of National Defense is consolidating troops from each military unit to reorganize the unit structure in accordance with Defense Reform 2.0; the plan includes reducing the garrison used by each unit to 70% of its current level. Accordingly, the demand for demolition work in the military is also expected to increase. However, the military regulations do not reflect the relevant laws that have been revised recently. This study identifies regulations and system improvements for demolition work suitable for the military based on an analysis of accident cases that have occurred during demolition work, of domestic and foreign laws and regulations related to military demolition work, and of the problems with current military safety management at each stage of planning, design, and construction. The study subsequently proposes improvements for military demolition work, including budget execution adjustment, the establishment of training courses, on-site inspections, the development of guidelines for military demolition work, the provision of risk assessment standards, and the need for the qualification of equipment operators.

• 해양환경안전학회지
• /
• 제25권7호
• /
• pp.819-826
• /
• 2019

정확한 도선사 수요와 공급을 예측하기 위해서는 수요산정의 결정요인을 도출할 필요가 있다. 왜냐하면 이는 선박과 항만의 안전을 확보하는 것과 직결되어 있기 때문이다. 적절한 도선사 수의 확보는 도선사의 수입과도 직결되는 문제이기 때문에 도선관계자, 정부 및 도선이용자간의 이해가 상충되기도 한다. 따라서 도선서비스 관련 이해관계자를 모두 만족시킬 수 있는 합리적인 도선사 수요산정 결정요인의 도출 및 그 수요예측을 통해 적절한 수의 도선사를 확보하여 양질의 도선서비스가 제공될 수 있도록 하여야 할 것이다. 이 연구는 현행 중앙도선운영협의회에서 사용하는 도선사 수요산정 결정요인의 문제점을 밝히고 그 개선점을 도출하기 위하여 현행 도선사 수요산정 결정요인의 산식에 대한 현황조사 및 분석, 이해당사자들에 대한 설문분석 및 해외사례조사 등의 방법론을 통해 합리적인 도선사 수요산정의 결정요소로서 총연평균도선시간, 연평균 도선사 근무시간 및 현행 도선사 수 3가지 요소를 도출하였다.

• 대한안전경영과학회지
• /
• 제8권5호
• /
• pp.139-150
• /
• 2006

The aim of this study is to establish an efficient distribution planning for a capacitated multi-stage supply chain. We assume that the demand information during planning horizon is given a deterministic form using a certain forecasting method. Under such a condition, we present a cost effective heuristic method for minimizing chain-wide supply chain inventory cost that is the sum of holding and backorder costs by using look-ahead technique. We cope with the capacity restriction constraints through look-ahead technique that considers not only the current demand information but also future demand information. To evaluate performance of the proposed heuristic method, we compared it with the extant research that utilizes echelon stock concept, under various supply chain settings.

• 대한안전경영과학회지
• /
• 제13권2호
• /
• pp.267-273
• /
• 2011

Since 'The Act on Private Investment of The Infrastructure' was established in 1994, private investment as well as government's investment in transport infrastructure has been active. However investment in transport infrastructure has more risks than others' due to uncertainty both in traffic volume and in construction cost. In the current appraisal procedure of deciding transportation infrastructure investment, instead of risk management, the sensitivity analysis considering only the changes of benefit, cost and social discount rate which are main factor affecting economic feasibility is carried out. Therefore the uncertainty of various factors affecting demand, cost and benefit are not considered in feasibility study. In this study the problems in current investment appraisal system were reviewed. Using Delphi technique the major factors which have high uncertainty in feasibility study were surveyed and then improvement plan was suggested in the respective of classic 4 step demand forecasting method. The range estimation technique was also mentioned to deal with the uncertainty of the future.

• 대한안전경영과학회:학술대회논문집
• /
• 대한안전경영과학회 2005년도 추계학술대회
• /
• pp.194-198
• /
• 2005

Inventory information system is providing the benefits of smoother demand, lower inventories(work in process, safety stock) and reduced costs. This study focused on improvement of safety level inventory efficiency by inventory information system. The results indicated that inventory information system allowed the company to serve its customers more surely and efficiently.

• Safety and Health at Work
• /
• 제11권3호
• /
• pp.353-360
• /
• 2020

Background: Urban bus drivers work under conditions that are among the most demanding, stressful, and unhealthy with higher rates of mortality and morbidity as well as absenteeism and turnover. Methods: Drawing on the job demand-resource model, this study investigates the impacts of job characteristics on emotional exhaustion and the effects of emotional exhaustion on job outcomes (including job satisfaction, life satisfaction, organizational commitment, and turnover intention) in the context of bus drivers. Results: Using self-reported survey data collected from a sample of 320 Taiwanese urban bus drivers, results reveal that role overload and work-family conflict (as job demand factors) positively relate to emotional exhaustion, and organizational support (as a job resource factor) is negatively associated with emotional exhaustion. Emotional exhaustion has negative effects on both job satisfaction and organizational commitment. Job satisfaction positively leads to life satisfaction, whereas organizational commitment negatively relates to turnover intention. Conclusion: This study concludes that role overload and work-family conflict as two stressors related to job demands and organizational support as the job resource factor to affect emotional exhaustion which further influence well-being in bus driver context. The moderating effects of both extraversion and neuroticism on the relationship between job demands and emotional exhaustion are evident.

• Safety and Health at Work
• /
• 제13권4호
• /
• pp.469-474
• /
• 2022

Background: Nowadays, counter-productive work behaviors (CWBs) have turned into a common and costly position for many organizations and especially health centers. Therefore, the study was carried out to examine and compare the demand-control-support (DCS) and effort-reward imbalance (ERI) models as predictors of CWBs. Methods: The study was cross-sectional. The population was all nurses working in public hospitals in Hamadan, Iran of whom 320 were selected as the sample based on simple random sampling method. The instruments used were Job Content Questionnaire, Effort-Reward Imbalance Questionnaire, and Counterproductivity Work Behavior Questionnaire. Data were analyzed using correlation and regression analysis in SPSS18. Results: The findings indicated that both ERI and DCS models could predict CWB (p ≤ 0.05); however, the DCS model variables can explain the variance of CWB-I and CWB-O approximately 8% more than the ERI model variables and have more power in predicting these behaviors in the nursing community. Conclusion: According to the results, job stress is a key factor in the incidence of CWBs among nurses. Considering the importance and impact of each component of ERI and DCS models in the occurrence of CWBs, corrective actions can be taken to reduce their incidence in nurses.

• 해양환경안전학회지
• /
• 제27권7호
• /
• pp.918-923
• /
• 2021

정부는 공유수면 매립사업의 계획적인 관리를 위해, 10년 주기의 공유수면 매립기본계획을 수립하고 있다. 그러나 수시변경을 통한 매립사업을 추진하는 경우가 상당한 비중을 차지하고 있는 것으로 나타났다. 이에 기본계획의 실효성에 대한 의문이 제기되고 있으며, 이를 보완하기 위한 장기 매립 수요 추세 분석에 대한 필요성이 증가하고 있다. 이에 본 연구에서는 그간의 연간 매립 실적 자료를 활용하여 매립 수요 추세 분석을 수행하였다. 분석 결과, 국내 공유수면 매립 수요는 지속적으로 하락하는 추세인 것으로 나타났으며, 특히 매립기본계획 체제로 전환된 1990년대 이후에는 그 추세가 뚜렷하게 나타나고 있는 것으로 나타났다. 또한 2021-2030년까지 총 매립 수요는 최대 13.8 km²에서 최소 1.7 km² 수준으로 산정되었다.

• 해양환경안전학회:학술대회논문집
• /
• 해양환경안전학회 2017년도 공동학술발표회
• /
• pp.267-267
• /
• 2017