• Journal of the Korea Safety Management & Science
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• v.8 no.1
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• pp.1-16
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• 2006

We applied the TPM to loading and unloading equipments of Incheon port and compared with the current maintenance of Incheon port's equipments. Also we analyzed the death disaster causes of equipments and work tools and suggested TPM techniques as a plan of disaster prevention. Using TPM to the loading and unloading equipments we expect to obtain the breakdown zero, defective zero, and disaster zero. And then it should raise the productivity of harbor loading and unloading equipments.

• Journal of the Korea Safety Management & Science
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• v.25 no.1
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• pp.15-21
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• 2023

In modern society, the delivery service market has grown explosively due to rapid changes in social structure and the recent COVID-19 pandemic. Therefore, various problems such as injury to workers and an increase in human accidents are occurring due to the loading and unloading of parcels. In order to solve this problem, domestic company n is developing a "robot-based cargo loading and unloading system". In developing a new technology system, quantitative reliability targets should be set for efficient operation and development. In this paper, reliability analysis was conducted through field data for the pneumatic gripper of the "robot-based cargo loading system". The reliability of the failure data was analyzed to estimate the distribution parameters and MTTF. Random data was derived for the probability of occurrence of a failure with the estimated value. By repeating the simulation to predict the number and year of failures according to the estimated parameters of the probability distribution, it was proposed as a method that reflects realistic probabilities rather than calculating with simple arithmetic using the average MTTF previously used in the field.

• Geomechanics and Engineering
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• v.14 no.2
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• pp.195-202
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• 2018

Many laboratory experiments on crack propagation under uniaxial loading and biaxial loading have been conducted in the past using transparent materials such as resin, polymethyl methacrylate (PMMA), etc. However, propagation behaviors of three-dimensional (3D) cracks in rock or rock-like materials under tri-axial loading are often considerably different. In this study, a series of true tri-axial loading tests on the rock-like material with two semi-ellipse pre-existing cracks were performed in laboratory to investigate the acoustic emission (AE) characteristics and propagation characteristics of 3D crack groups influenced by intermediate principal stress. Compared with previous experiments under uniaxial loading and biaxial loading, the tests under true tri-axial loading showed that shear cracks, anti-wing cracks and secondary cracks were the main failure mechanisms, and the initiation and propagation of tensile cracks were limited. Shear cracks propagated in the direction parallel to pre-existing crack plane. With the increase of intermediate principal stress, the critical stress of crack initiation increased gradually, and secondary shear cracks may no longer coalesce in the rock bridge. Crack aperture decreased with the increase of intermediate principal stress, and the failure is dominated by shear fracturing. There are two stages of fracture development: stable propagation stage and unstable failure stage. The AE events occurred in a zone parallel to pre-existing crack plane, and the AE zone increased gradually with the increase of intermediate principal stress, eventually forming obvious shear rupture planes. This shows that shear cracks initiated and propagated in the pre-existing crack direction, forming a shear rupture plane inside the specimens. The paths of fracturing inside the specimens were observed using the Computerized Tomography (CT) scanning and reconstruction.

• Journal of the Korean Geotechnical Society
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• v.34 no.5
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• pp.5-17
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• 2018

In this study, the static and dynamic load tests were carried out to propose the safety factor of steel prebored and precast piles in weathered rocks. The axial load tests have been conducted on test piles with nominal diameters of 0.508 and 0.457 m. The piles were subject to static loading tests (14 times) and dynamic loading tests (EOID 14times, Restrike 14times). The dynamic loading tests were first executed after the casting of test piles ((1) initial EOID test). (2)In the succeding 28 days from completion of construction, static load tests were performed and (3)final restrike tests were carried out after 15 days from the static test. As a result, the bearing capacity based on Davisson method was 15% higher than that of the restrike tests. The bearing capacity of the static load tests were larger than that of the dynamic tests. By comparing the safety factor through various loading tests, the safety factor of dynamic loading tests were suggested to be lowered to 1.75 from the conventional 2.0.

• Journal of the Korean Society of Safety
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• v.9 no.1
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• pp.31-39
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• 1994

In this study, image processing were performed to recognize the shape of objects and find its center coordinate and direction to grisp the objects by the robot automatically. The proposed methods could be applied to objects even if light is reflected, and to identify the insides and outsides of objects by using the photo sensor and the difference of surface conditions. Also image segmentation is performed to the objects close to each other. These image processing methods will be increased the safety of operators by the automation of dangerous and hazardous machine works.

• Journal of the Korean Society of Safety
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• v.31 no.3
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• pp.109-115
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• 2016

This study examined the effects of safety-aisle on the safety climate, safety leadership, safety behavior, work loading and perceived accident risk in the small sawmilling industry. We distributed a questionnaire that measured various demographic variables, safety related variables by mail to 200 sawmilling companies. Finally 59 managers' and 129 workers' questionnaires were used for data analysis. An independent t-test was conducted to identify significant mean differences of safety related variables between safety-aisle installed and non-installed companies. Results indicated that mean differences of safety climate and safety behavior between safety-aisle installed and non-installed companies were significant. However, mean differences of safety leadership, work loading and perceived risk were not significant at the p < .05 level. Based on these results, the implications of this study and suggestions for future research were discussed.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.32 no.4
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• pp.449-455
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• 2022

Objectives: In order to provide basic data for future researchers, this study aims to explore future tasks after reviewing the changes in port safety management due to the enforcement of the Special Act on Port Safety. Methods: The provisions of the Special Act on Port Safety were analyzed and the latest literature related to port safety management was reviewed. Results: There are two major changes that have stemmed from the Special Act on Port Safety: 1. The scope of application for port participants has been expanded, safety education has been made compulsory, and safety management plans have been established and implemented for each business site. 2. The government is operating a port safety consultative body for each port and has hired one port safety inspector for each of the eleven local maritime and fisheries offices across the country. Future tasks include elaboration of port safety accident statistics, strengthening shipping companies' responsibility for stevedore safety, the unification of contracts, and government interest and support for port safety facilities. Conclusions: The primary feature of the Special Act on Port Safety is the emphasis on autonomous safety management by participants in port transportation. In addition, the enactment of the special law has allowed the Ministry of Maritime Affairs and Fisheries to actively intervene in port loading and unloading safety.

• International journal of advanced smart convergence
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• v.12 no.3
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• pp.233-243
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• 2023

In modern society, since the expansion of the e-commerce market and the spread of the pandemic, face-to-face business are gradually changing to non-face-to-face. In the logistics industry, the demand for unmanned courier storage is increasing due to lack of loading space from urbanization and courier theft accidents. As the demand for unmanned parcel lockers increases, improved functions such as food storage and efficient space loading are required. This study develops an integrated model-based evaluation procedure of product based on performance factors according to the IEC 61508 standard for newly unmanned parcel storage devices with active loading technology, and derive Critical Technology Element based on the product's core functions and performance goals. As proposing these research, We expect improve the safety and reliability of development targets by identifying and evaluating elements.

• Safety and Health at Work
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• v.4 no.2
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• pp.105-110
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• 2013

Background: To determine the influence of lifting speed and type on peak and cumulative back compressive force (BCF) and shoulder moment (SM) loads during symmetric lifting. Another aim of the study was to compare static and dynamic lifting models. Methods: Ten male participants performed a floor-to-shoulder, floor-to-waist, and waist-to-shoulder lift at three different speeds [slow (0.34 m/s), medium (0.44 m/s), and fast (0.64 m/s)], and with two different loads [light (2.25 kg) and heavy (9 kg)]. Two-dimensional kinematics and kinetics were determined. A three-way repeated measures analysis of variance was used to calculate peak and cumulative loading of BCF and SM for light and heavy loads. Results: Peak BCF was significantly different between slow and fast lifting speeds (p < 0.001), with a mean difference of 20% between fast and slow lifts. The cumulative loading of BCF and SM was significantly different between fast and slow lifting speeds (p < 0.001), with mean differences ${\geq}80%$. Conclusion: Based on peak values, BCF is highest for fast speeds, but the BCF cumulative loading is highest for slow speeds, with the largest difference between fast and slow lifts. This may imply that a slow lifting speed is at least as hazardous as a fast lifting speed. It is important to consider the duration of lift when determining risks for back and shoulder injuries due to lifting and that peak values alone are likely not sufficient.

• Journal of Auto-vehicle Safety Association
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• v.12 no.4
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• pp.54-60
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• 2020

In a previous study, an investigation of occupant behaviors and injuries (to the head and chest) was performed during vehicle impact loading cases in order to ensure the safety of wheelchair passengers on a bus. The computational results showed overall safety tolerances of wheelchair occupants under different accident configurations. The bus crashworthiness is described as the capability of a bus to protect occupants during rollover loadings. The residual space containing occupants should be undamaged without any intrusions. However it is necessary to evaluate the residual space according to the bus occupant kinematic analysis under the rollover crash simulation. This study focuses on the evaluation of occupant behaviors during rollover loading cases in order to ensure the safety of bus passengers sitting in general seats and wheelchairs and evaluates the residual space of the bus by analyzing the bus occupant kinematics.