• Transactions of Materials Processing
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• v.20 no.5
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• pp.377-386
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• 2011

During stamping processes, the air trapped between sheet metal and the die cavity can be highly compressed and ultimately reduce the shape accuracy of formed panels. To prevent this problem, vent holes and passages are sometimes drilled into the based on expert experience and know-how. CAE can be also used for analyzing the air behavior in die cavity during stamping process, incorporating both elasto-plastic behavior of sheet metal and the fluid dynamic behavior of air. This study presents sheet metal forming simulation combined simultaneously with simulation of air behavior in the die cavity. There are three approaches in modeling of air behavior. One is a simple assumption of the bulk modulus having a constant pressure depending on volume change. The next is the use of the ideal gas law having uniform pressure and temperature in air domain. The third is FPM (Finite point method) having non-uniform pressure in air domain. This approach enables direct coupling of mechanical behavior of solid sheet metal and the fluid behavior of air in sheet metal forming simulation, and its result provides the first-hand idea for the location, size and number of the vent holes. In this study, commercial software, PAM-$STAMP^{TM}$ and PAM-$SAFE^{TM}$, were used.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2024-2029
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• 2005

In this paper, it is shown how a mobile robot can navigate with high speed in dynamic real environment. In order to achieve high speed and safe navigation, a robot collects environmental information. A robot empirically memorizes locations of high risk due to the abrupt appearance of dynamic obstacles. After collecting sufficient data, a robot navigates in high speed in safe regions. This fact implies that the robot accumulates location dependent environmental information and the robot exploits its experiences in order to improve its navigation performance. This paper proposes a computational scheme how a robot can distinguish regions of high risk. Then, we focus on velocity control in order to achieve high speed navigation. The proposed scheme is experimentally tested in real office building. The experimental results clearly show that the proposed scheme is useful for improving a performance of autonomous navigation. Although the scope of this paper is limited to the velocity control in order to deal with unexpected obstacles, this paper points out a new direction towards the intelligent behavior control of autonomous robots based on the robot's experience.

• Journal of the Korean Society of Safety
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• v.30 no.4
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• pp.113-119
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• 2015

This study is to examine the workers' awareness of the safety in logistic centers. For that purpose, the exploratory factor analysis of workers' safety awareness in logistic centers was performed at first, and the 6 variables extracted from the factor analysis were then used to investigate the difference in intergroup awareness of the safety environment in the logistic centers. We administered a survey to 147 workers attending the logistic centers and collected data from them. The results of the study showed that the intergroup awareness of the safety environment turned out to be statistically different from each other in terms of working environment, safe behavior, work risk, safety knowledge and effort, risk justification and compromising attitudes. Experiences in industrial accidents influenced awareness of working environment, work risk and risk justification. The group who experienced accidents is more likely to feel risky and unsatisfied with working place, and their awareness toward risk justification was high as well. It was also observed that there exists awareness difference between manager group and worker group. The group who manages the working place showed more positive awareness of working environment, safe behavior, work risk, safety knowledge and effort, risk justification and compromising attitudes than the worker group. On the contrary, the worker group showed high recognition in risk of working place, and felt that they are willing to compromise on safety for increasing production. The scale of the logistic center produced negative influence on awareness of safety. The group in small logistic center showed the highest awareness in safety, whereas the group in large logistic center with more than 100 workers showed the highest awareness in risk. They are more likely to deviate from correct and safe work procedures due to over-familiarity with the job, as well. The findings suggest that there is a need for the safety management and education to change the workers' understanding and attitudes towards safety.

• Journal of Korean Tunnelling and Underground Space Association
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• v.5 no.2
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• pp.101-113
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• 2003

Nowadays, the construction of new ground structures, which can influence the stability of existing underground structures, is increasing. Consequently, many technical problems occur during the design and construction stage of the new structures. In constructing a neighboring structure, reasonable design and construction is strongly required to balance between the stability of the existing underground structures and the economy of construction of the new structure in terms of the importance of the existing underground structures. Many researches have been performed to estimate the safe region and behavior of underground structures. Constructing a new ground structure above the existing underground structure, external loads are to be applied to the existing underground structure. In this study, therefore, the stability and safe region of the existing underground structure was re-established with respect to the relative location of the new ground structure with the underground structure, the depth from surface to top of the underground structures, and ground conditions.

• Journal of the Korean Society of Clothing and Textiles
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• v.44 no.1
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• pp.126-140
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• 2020

This study analyzed the self-identified cold tolerance and wearing behavior of teenagers inside and outside the classroom during winter, considering recent climate changes. A questionnaire was divided into four parts-general information, thermal and comfort sensation inside and outside classroom, self-identified cold tolerance, and wearing behavior to collect data from 322 students. Over several years, changes were noted in respondents' wearing behavior during winter outings, with the biggest being the purchase of a "long padded jacket" for warmth while outside. Most respondents showed similar wearing behavior, such as no difference between the number of clothes worn in a classroom maintained at 20℃ (girls: 8.0±3.1 layer, boys: 6.5±2.1 layer) and outside (girls: 8.8±3.4 layer, boys: 7.1±3.0 layer), despite feeling differently about the thermal sensation inside and outside the classroom. This difference may due to a teenager's lack of knowledge about temperature and their tendency to follow clothing trends. Female students were more sensitive to the cold and wore more garments inside and outside the classroom. Gender-related differences should be considered when educating teenagers about safe and healthy clothing.

• Journal of Navigation and Port Research
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• v.31 no.4
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• pp.281-287
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• 2007

Human factors have been considered the primary reason of marine accidents. Especially, the collision between vessels is mostly mused by human behavior. However, there have not been many researches to clarify the reason of marine accidents mused by human factors quantitatively. In order to understand human factors and to enhance safe navigation systematically, using a full mission ship-handling simulator, we've investigated the characteristics of avoiding behavior taken by mariners. Further in order to apply the characteristics more widely and effectively, it's necessary to formulate the standard behavior for ship-handling in the condition of collision avoidance. Is this study, therefore, we intended to propose the concept to model the mariner's standard behavior on the handling of collision avoidance as the first step. As a result, we confirmed the contents of information processing in ship-handling that mariner's generally taking to avoid collision.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.5
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• pp.167-178
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• 2021

This study aims to identify the influence of paradoxical leadership on proactive work behavior mediated through psychological safety in the hotel industry. This study employs survey data of five-star deluxe hotels in South Korea using convenience sampling. The number of 270 cases was used for analysis and the hypotheses were analyzed with structural equation modeling and AMOS 20. Paradoxical leadership includes five sub-variables of self-centeredness with other-centeredness (SO) distance and closeness (DC), uniformly and individualization (UI), work requirements and flexibility (RF), and decision control and autonomy (CA). The results indicate that DC, UI, and CA positively influence psychological safety. Further, RF and CA make a positive impact on proactive work. Psychological safety fully mediates the effect of DC and UI on proactive work behavior and partially mediates the effect of CA on it. The findings of this study suggest that the impact of paradoxical leadership on proactive work behavior can be strengthened when this relationship is accompanied with psychological safety and other mediation variables for the relationship need to be further investigated. This study suggests how hotel managers enhance the level of proactive work behavior by training themselves to be paradoxical leaders and making psychologically safe environment.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.485-488
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• 2008

The structure supporting road sign is a road information facility for ensuring the safe transportation and smooth traffic. But, lots of road information facilities were damaged by the typhoon "Maemi" in 2003. Such damaged facilities should be rehabilitated and could increase economic loss by causing traffic accident. Therefore, in this study, behavior that reduce wind load and improve wind resistance of the structure supporting road sign are studied about wind load beyond design specification by abnormal climate as below. The first is wind load reducing technique such that shear key resist wind load that is not greater than design wind speed but in case that it is over the design wind limit, column member is rotated on the inner steel pipe axis by the brittle failure of shear key. The second is the technique such that fail-safe the overturning of road sign panel by equipment installation in the vertical member. The third is the technique of installing stiffening plate inside the vertical member to relieve stress concentration.

• International conference on construction engineering and project management
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• 2020.12a
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• pp.122-128
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• 2020

This research investigates how a Virtual Reality (VR)-based simulation could be used to train safe operation skills for forklift operators. Forklift operation is categorized as high-risk work by many occupational health and safety regulators and authorities due to high injury and fatality rates involved with forklifts. Therefore, many safety guidelines have been developed for forklift operators. Typically, forklift operation safety training is delivered based on instructional texts or videos, which have limitations in influencing people's safety behavior. Against this background, we propose a VR-based forklift simulator that can enable safe operation skills training through a feedback system. The training program consists of several modules to teach how to perform the basic tasks of forklift operation, such as driving, loading and unloading, following the safety guidelines. The system provides instantaneous instructions and feedback regarding safe operation. This training system is based on the model of "learning-by-doing". The user can repeat the training modules as many times as necessary before being able to perform the given task without violating any safety guidelines. The last training module tests the user's acquisition of all safety skills required. The user feedback from several demonstration sessions showed the potential usefulness of the proposed training system.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.04a
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• pp.81-88
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• 2000

This paper based on a survey of the 1995 Hyogo-Ken Nanbu Earthquake analyzes human behavior by the house pattern through the correspondence analysis in an area of Shindo 7: earthquake with an intensity of 7 on the Japanese scale. According to the analysis the following proposals are shown as a space safety planning: First : To establish the space allotment based on which the role behavior among family members are smoothly executed, . Second In the apartment house it is important to install a common space or a "Helping Neighbot" -route to the adjoining dwelling unit which is safe for residents' activities and effective for the improvement of the earthquake-resistant structure of the building. building.