• Safety and Health at Work
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• v.13 no.2
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• pp.148-154
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• 2022

Background: Bus driving is a mentally demanding activity that requires prolonged attention to ensure safety. The aim of the study was to assess mental fatigue caused by driving a public bus and to find a profile of workers at higher risk. Methods: We evaluated changes of critical flicker fusion (CFF) (index of central arousal) and heart rate variability (HRV) (index of autonomic balance) in a 6-hour driving shift on a real route, in 31 professional bus drivers, and we tested the influence of personal factors such as sleep quality, BMI, and age. Paired t-test was used to test differences of CFF and HRV between both initial and final phase of driving, while multiple linear regression tested the influence of personal variables on the indexes of mental fatigue. Results: Results showed that CFF significantly decreased after 6 hours of bus driving (41.91 Hz, sd 3.31 vs. 41.15 Hz, sd 3.15; p = 0.041), and heart rate significantly decreased in the final phase of driving, with respect to the initial phase (85 vs. 78 bpm, p = 0.027). Increasing age (beta = -0.729, p = 0.022), risk of obstructive sleep apnea syndrome (beta = -0.530, p = 0.04), and diurnal sleepiness (beta = -0.406, p = 0.017) showed a significant effect on influencing mental fatigue. Conclusion: Elderly drivers at higher risk of sleep disorders are more prone to mental fatigue, when exposed to driving activity. Monitoring indexes of central arousal and autonomic balance, coupled with the use of structured questionnaires can represent a useful strategy to detect profile of workers at higher risk of mental fatigue in such duty.

• Journal of the Korean Society of Safety
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• v.20 no.2 s.70
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• pp.61-66
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• 2005

This paper presents an human reliability assessment(HRA) for a installation task of the temporary power cable in construction fields. HRA is evolved to ensure that the workers could reliably perform critical tasks such as a process of the temporary power cable. Human errors are extremely commonplace, with almost everyone committing at least some errors every day. The considerable parts of electric shock accidents in the construction field are caused by a series of human errors. Therefore it is required to analyze the human errors contained in the task causing electric shock event, the event tree analysis(ETA) is adopted in this paper, and particularly human reliability was estimated for a installation task of the temporary power cables. It was assumed that the error probabilities of the human actions may be obtained using the technique for human error rate prediction(THERP). The results show that the predominant task on reliability in the cable installation tasks is check-out tasks and the probability causing electric shock by human errors was calculated as $1.0\times10^{-9}$.

• Journal of the Korean Society of Safety
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• v.38 no.3
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• pp.93-101
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• 2023

The COVID-19 pandemic has significantly impacted how people work, resulting in a massive shift towards working from home or remotely. Work from home has played a critical role in reducing the transmission of COVID-19 by limiting in-person interactions and reducing the density of people in office buildings. It also enabled businesses and organizations to continue operating while keeping their employees safe and healthy. The COVID-19 pandemic accelerated the adoption of work from home in business and organizational sectors worldwide, and it is likely to continue as a preferred mode of work even after the pandemic is over. This shift towards working from home has not only impacted the way people work but also has significant implications for urban development, transportation, and the environment. This study intends to develop measures for addressing potential physical and mental health issues among remotely working employees. Additionally, it identifies the major influencing factors of home workers' health hazards and proposes improvement measures that can be applied to working from home, along with existing laws and prevention methods.

• Journal of the Korea Institute of Building Construction
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• v.21 no.5
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• pp.397-408
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• 2021

The construction industry has the highest occupational accidents/injuries and has experienced the most fatalities among entire industries. Korean government installed surveillance camera systems at construction sites to reduce occupational accident rates. Construction safety managers are monitoring potential hazards at the sites through surveillance system; however, the human capability of monitoring surveillance system with their own eyes has critical issues. A long-time monitoring surveillance system causes high physical fatigue and has limitations in grasping all accidents in real-time. Therefore, this study aims to build a deep learning-based safety monitoring system that can obtain information on the recognition, location, identification of workers and heavy equipment in the construction sites by applying multiple object tracking with instance segmentation. To evaluate the system's performance, we utilized the Microsoft common objects in context and the multiple object tracking challenge metrics. These results prove that it is optimal for efficiently automating monitoring surveillance system task at construction sites.

• Journal of Food Hygiene and Safety
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• v.14 no.3
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• pp.293-304
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• 1999

The purpose of this study was to evaluate the microbiological quality, and to assure the hygienic safety of the food production in the university food service facility located in Seoul in accordance with the Hazard Analysis Critical Control Point(HACCP) concepts. In the hygienic state assessment of kitchen, it has revealed that it was very important to remove water from the kitchen floor and to establish standard method for disinfection of cooking utensils. And foodservice workers were required to have training program for the safe handling of food and utensils since they did treat food without hygienic gloves. The kitchen layout had to be improved because the near distance of table with heating unit and shelf might cause the growth of microorganisms when prepared food was kept on the shelf. In terms of the timetemperature measurement and microbiological quality assessment during each of the food production phases, most of sengchae (raw vegetable dish) and namul (cooked vegetable dish) were treated within danger zone for food safeness ($5~60^{\circ}C$). It has shown that the microbiological quality of raw materials was very much inferior at the time of receiving based on the TPC($10^{5}~10^{7}$), coliform($10^{3}~1O^{6}$), which was not acceptable level(TPC:$10^{6}$, coliform:$10^{3}$) suggested by Solberg. Microbiological growth has increased in the both of sengchae and namul considerably during most of food production phase. Therefore, it is extremely important to reduce holding and serving time and to avoid treating food within the danger zone for food safeness. In addition, the prevention of cross-contamination during mixing the ingredients with improper equipments and with insanitary treatments by workers was also important to keep the food safety in this speciqic university foodservice facility.

• Journal of the Korean Home Economics Association
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• v.41 no.10 s.188
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• pp.101-116
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• 2003

The study was conducted to establish hygienic standards of salad items for pizza restaurant located in Seoul by applying HACCP system during the summer of 2000. The study measured temperature, time, pH, Aw and microbial assessments. The hygienic conditions of the kitchen and workers were on the average(1.21, 1.0 out of 3 pts.), but some improvement should be made: separate use of trash can and leftover disposal, separate use of knives and cutting boards, habits for hand washing and wearing hygienic gloves. For salad production, all procedures were peformed under food safety danger zone ($5{\~}60^{\circ}C$). The ingredients were mostly above pH 5.0 and high in Aw($0.94{\~}0.99$). Microbial assessments for salad production revealed that TPC($1.8{\times}10^3{\~}1.0{\times}10^{10}CFU/g$) and coliforms($1.5{\times}10{\~}5.2{\times}10^5 CFU/g$) exceeded the standards by Solberg et al.(TPC: $10^6CFU/g$, coliforms: $10^3CFU/g$). S. aureus was not detected but Salmonella was found in three food items(egg, macaroni and macaroni salad). Moreover, the workers' hands contained 3.1 104 CFU/g of TPC and 4.2 102 CFU/g of S. aureus requiring further remedy since it exceeded the safety standards suggested by Harrigan and McCance (500 CFU/g of TPC per $100cm^2$ and 10 CFU/g of coliforms per $100cm^2$). According to the critical control point(CCP) decision tree analysis, vegetable receiving, vegetable holding, mixing, display on coleslaw, macaroni draining, display on macaroni salad, egg peeling & cutting, apple cutting, and display on salad bar were determined as CCPs. From the findings it would be suggested that purchase of Quality materials, short holding and display time, storing food at right temperature, using sanitary cooking utensils, and improvement of workers' food handing practices are needed to ensure the safe salad production in this specific pizza restaurant.

• Safety and Health at Work
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• v.3 no.1
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• pp.43-49
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• 2012

In recent years, various international organizations have raised awareness regarding psychosocial risks and work-related stress. European stakeholders have also taken action on these issues by producing important documents, such as position papers and government regulations, which are reviewed in this article. In particular, 4 European models that have been developed for the assessment and management of work-related stress are considered here. Although important advances have been made in the understanding of work-related stress, there are still gaps in the translation of this knowledge into effective practice at the enterprise level. There are additional problems regarding the methodology in the evaluation of work-related stress. The European models described in this article are based on holistic, global and participatory approaches, where the active role of and involvement of workers are always emphasized. The limitations of these models are in the lack of clarity on preventive intervention and, for two of them, the lack of instrument standardization for risk evaluation. The comparison among the European models to approach work-related stress, although with limitations and socio-cultural differences, offers the possibility for the development of a social dialogue that is important in defining the correct and practical methodology for work stress evaluation and prevention.

• Safety and Health at Work
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• v.14 no.3
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• pp.243-249
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• 2023

Background: Southeast Asia has many people who work in the agriculture sector. Not many stakeholders pay special attention to the health of farmers, even though they are exposed to various types of hazards. One of the most common health complaints among farmers is related to work-related musculoskeletal disorders (WMSDs). This study aims to assess the prevalence of WMSDs and factors associated with them among farmers in Southeast Asia. Methods: A literature search on PubMed, ScienceDirect, Scopus, and EBSCO was conducted. Articles were included if they studied ergonomic problems among farmers from 11 countries in the Southeast Asia region and were published during 2015-2022. The Critical Appraisal Skills Program was used to evaluate the quality of the articles. The search process and retrieval process reflected PRISMA's recommendation. Result: There were 14 studies found from 3 countries that had published articles in PubMed and ScienceDirect, including Thailand [8], Indonesia [4], and Malaysia [2]. The prevalence of WMSDs in Thailand, Indonesia, and Malaysia was 78,31%, 81,27%, and 88,39%, respectively. Common factors associated with WMSDs include age, sex, smoking habits, drinking alcohol habits, working period (years), type of work, awkward position, non-ergonomic equipment, repetitive movements, and lifting heavy loads. Conclusion: The prevalence of WMSDs among farmers in Southeast Asia is considerably high. Effective intervention is essential for reducing the prevalence and protecting workers' health and well-being.

• Korean Journal of Construction Engineering and Management
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• v.24 no.5
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• pp.73-82
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• 2023

Optimization of Construction Site Layout Planning (CSLP) heavily relies on workers' travel paths. However, traditional path generation approaches predominantly focus on the shortest path, often neglecting critical variables such as individual wayfinding tendencies, the spatial arrangement of site objects, and potential hazards. These oversights can lead to compromised path simulations, resulting in less reliable site layout plans. While Deep Reinforcement Learning (DRL) has been proposed as a potential alternative to address these issues, it has shown limitations. Despite presenting more realistic travel paths by considering these variables, DRL often struggles with efficiency in complex environments, leading to extended learning times and potential failures. To overcome these challenges, this study introduces a refined model that enhances spatial navigation capabilities and learning performance by integrating workers' visibility into the reward functions. The proposed model demonstrated a 12.47% increase in the pathfinding success rate and notable improvements in the other two performance measures compared to the existing DRL framework. The adoption of this model could greatly enhance the reliability of the results, ultimately improving site operational efficiency and safety management such as by reducing site congestion and accidents. Future research could expand this study by simulating travel paths in dynamic, multi-agent environments that represent different stages of construction.

• Journal of the Korean Society of Safety
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• v.37 no.4
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• pp.36-43
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• 2022

Generally, in construction sites, the pipe support installation workers often use support pins of 9~10 mm which are much smaller than the safety standard sizes for work convenience. Although the safety certification standard thickness of the support pins is 11 mm, and the supervisors are often indifferent to this. Hence, products with far lower performance than the pipe support safety certification value of 40,000 N, which is applied in the supporting post-structural review, are used. Accordingly, this acts as a factor causing collapse accidents in the process of pouring concrete at the construction site. Therefore, this study performed compression experiments on new and reused pipe supports to determine how the thickness of the support pins affects the structural compression performance of the pipe support by considering the thickness of the support pins as a critical variable among various factors affecting the pipe support performance. In the course of the study, the compression test of the pipe support (V2, V4) for the new products showed that only 14 (58.3%) of the total 24 samples satisfied the safety certification standard value of 40,000 N, which indicates that more thorough quality control is required in the manufacturing process. Additionally, comparing the thickness of the support pins and their fracture shape shows that the pipes with support length of 4.0 m or longer are much more affected by the buckling of the entire length than the thickness of the support pins. Of the several factors affecting the performance of reused pipe supports, it was found that, similar to the new products, the use of support pins, with thickness of 12 mm rather than 11 mm, can satisfy the safety certification value more appropriately. Therefore, regardless of the state of usage, it could be concluded that it is necessary to use 12 mm products, whose thickness is larger than that of the safety certification standard value of 11 mm, to improve the performance of the pipe supports.