• Tribology and Lubricants
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• v.30 no.3
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• pp.183-188
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• 2014

In this paper, we present our analysis of tribological failure examples for an anti-lock brake system(ABS) in a car. The study range of this paper is to improve the quality of ABS system by analyzing with sensor, computer, actuator and oil lines. In the first example, the brake leak from hydraulic supply line in a caliper on the rear left side of the ABS hydraulic modulator. This produces the sponge phenomenon, where the car does not brake even when the driver operates the brake pedal. The hydraulic unit operating ABS is actuator that play role regulating drive condition according with the oil pressure supplied with wheel of a car. In the second example, the service man does not completely tighten the fixed bolt after repairing the car. This causes the ABS warning lamp to light up as the ABS wheel speed sensor cannot detect whether the ABS has been activated. In the third example, the ABS electronic control unit is separated from the soldered part of the inner circuit board. Consequently, the ABS fails in control because the ABS motor pump receives no-signal for the hydraulic unit. The wheel speed sensor has to large durability because of giving signal of acting condition to computer by detected the acceleration and deceleration of wheel of a car. In the fourth example, the ABS warning lamp lights up of when cracks propagate in the circuit board soldering part. The circuit of this computer is very important part for input and output the operating signal of system. Such failures can aggravate the durability of the ABS. Thus, the ABS needs to be optimized to eliminate malfunction phenomenon.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.4 no.2
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• pp.198-207
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• 1994

In order to evaluate the effectiveness of environmental intervention of work place, metal mercury concentration in air and in urine of the total 43 workers for 3years from December 1991 to October 1993 in a fluorescent lamp manufacturing industry exposed to mercury, was measured before and after implementation of controls such as establishing exhaust ventilation at the department of exhaustion, coating the floor of work place with epostane, cleaning of the floor, improved housekeeping, and etc. The results were as follows. 1. Before the intervention(December 1991) 39.0% exceeded metal mercury Threshold Limit Value(TLV, $0.05mg/m^3$). After the intervention(October 1993) 10.0% exceeded TLV and geometric mean of mercury in air was $0.1mg/m^3$, and showed effectiveness rate of intervention to be 74.4% 2. After the intervention, geometric means of mercury concentrations in air were 0.013, $0.019mg/m^3$ and showed effectiveness rate of intervention to be 76.6%, 65.5% in A factory(right tube lamp)and at exhaustion department, respectively, A follow up survey fround statistically significant reductions in mercury concetration in air three years later. 3. Mercury concentration in urine of 11 workers(29.7%) exceeded warning level of $100{\mu}l/l$ before the intervention. After the intervention, of 3workers(8.8%) exceeded warning level and geometric mean of mercury concentration($26.5{\mu}l/l$) in urine was 2.4 times than that of before the intervention. Geometric means of mercury concentrations in urine of workers at exhaustion department, at sealing and aging department were 44.0, $77.7{\mu}l/l$, respectively and they decreased 2.3, 3.2 times than that of before the intervention.

• Journal of Sport and Applied Science
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• v.5 no.1
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• pp.11-15
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• 2021

Purpose: Swimming industry is improving faster than the other types of sport industries and populations of participating swimming are promptly increasing. Lack of recognition of fire safety in swimming facilities is issues related-studies has only recently begun to pay attention. This study is to review and extract fire safety factors for managing swimming pool. Research design, data, and methodology: The study reviewed related-ordinances, governmental documents, and studies discussing safety management of sport facility. Given the literature review, the study produced an initial construct presenting items and factors including fire safety elements and experts' review were conducted to ensure conceptual validity. Finally, the study generated the final factors and subitems representing fire safety elements for swimming pool management. Results: The study confirms factors and elements as follows: the study identifies fire safety equipments as first factors presenting fire extinguisher' place, its proper run, check list and so forth, Second factor is warning system including fire warning equipment, its proper operation, sprinkler and its proper operation, switch and lamp of emergency panel and their proper run and so on. Third factor is evacuation system including a fire exit, exit sign, broadcasting equipment, and their proper operation, and so on. The other factors are an electronic equipment and its subelements, gas management including safety management of LPG, gas valve, pipe, and fire prevention facility including a fire door and its proper operating. Conclusions: Regarding safety management of swimming pool, further discussions and implications were made, and future directions for related-studies were discussed.

• Journal of the Korean Institute of Landscape Architecture
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• v.47 no.5
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• pp.41-48
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• 2019

Our daily lives are changing at a rapid pace and the concept of smart city is spreading, as the information communication technologies apply to various fields. However, efforts to prepare for changes in society due to technological evolution are insufficient in the field of landscape architecture. The purposes of this study are to explore the concept of smart parks, to investigate how smart technology has been applied to parks, and to identify the users' perception and satisfaction on smart park services. To this end, we conducted literature review, focus group interviews with experts, and a questionnaire survey with 180 users of the IoT See pilot smart park in Daegu. Smart parks can, as a result, be defined as sustainable parks that improve users' experience in parks and solve social and environmental problems faced by utilizing various high technology. Smart technologies introduced at the park so far have been mostly focused on safety and environmental areas, including AI CCTV, smart street lamp, and fine dust warning devices. The results of survey showed that not many users were aware of the smart services the park provided due to the lack of public communication as well as the nature of maintenance-oriented smart services. The survey also found that AR services for the education of historic parks were the least utilized, while solar power benches and WiFi service were most preferred by the park users. In conclusion, smart technologies need to be integrated with diverse park contents more centered user needs, providing services to enhance safety and environmental management in order to develop user-oriented smart parks.