• Journal of the Korea Safety Management & Science
• /
• v.20 no.3
• /
• pp.21-26
• /
• 2018

This paper describes result of a study on safety against a fire of charging cable for mobile phone for vehicle. Combustion on the USB cable in the car was happened while driving. Gas coming from the burning USB cable could be a reason which can make a secondary car accident since the driver also can be embarrassed while driving. In order to prevent a secondary car accident connected on the road, to research a reason why USB cable can emit gas and be burned in charging. We did simulation test with abnormal fault condition for the electronic component on the board in the USB cable. So we get the result from abnormal fault condition simulation test, for instance, shorted test for output terminal of 8 pin switch, shorted test for chip resistor after thermal aging in the condition $25^{\circ}C$, 93 % RH during 48 hours. To analysis the result of all test, Combustion on the USB cable was not the 8 pin but other electrical component such as a chip resistor. Therefore we guess that the reason for USB cable combustion in charging in a car was not 8 pin and a LED but another defective component.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2000.11c
• /
• pp.722-728
• /
• 2000

This study of field control machine in the recycled vinyl rail is gantry crane type and promoting agricultural automatization through self-controlled spraying, harvesting and conveyance. In addition to, that control machine could get a cost and labor reduction effect through automatization and make better environment by preventing farmers from agrichemical damage, accidents and recycling wasted vinyl. That machine is able to be divided as traveling, spraying, harvesting and conveyance sections. In driving section consists of girder frame, carrier, rail, control system, driving system, working machine, rail and loading device for working machine. This machine has following advantages to be able to bring a big innovation in the agricultural industry. I) Accurate performance is able to be done by proper positioning due to based on the rails. 2) The soil is not made hard like heavy tractor 3) The wheel is not sank into the soil and slipped well under rain like heavy tractor. Therefore, weather and soil situation could not affect working condition. 4) Complete unmanned control and 24hours-working are available due to traveling on the rails. 5) It could use various energy resources like not only liquid fuel but also solar, common electronic power due to traveling on the rails.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.17 no.9
• /
• pp.2153-2159
• /
• 2013

In order to drive a vehicle safely, driver needs to check status of the car. Many moderns are having trouble to spare time to visit auto mechanic and have car mechanics to check their car other than their office hours. If the car status cannot be inspected regularly, it is likely to cause a big accident threatening the surroundings as well as driver's life. Inspection tool and system help driver to check their own vehicle status personally are required for preventing it. In this paper, it designed and realized system that records driving information based on changing data of vehicle (location and automotive internal data) and allows driver can check the vehicle status easily and further, driver can share the driving information with repair shop via the Internet to receive detailed inspection service for car status.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.55 no.2
• /
• pp.129-137
• /
• 2019

This study was conducted to investigate the effects of underwater noise caused by pile driving during marine construction on fish. In this study, the three gray rockfish were released about 1 km away from the construction site of wind power generation on July 18, 2018 and traced using two acoustic telemetry techniques. The behavior of the fish was analyzed by calculating the moving distance, swimming speed and direction of the gray rockfish. In the results of the acoustic tracking using the ship, the rockfish moved about 2.11 km for about two hours at a speed of $0.28{\pm}0.14m/s$ (0.94 TL/s). The bottom depth of the trajectory of the rockfish was $1.0{\pm}0.6m$ on average. There was a significant directionality in swimming direction of the gray rockfish, and there was no significant correlation between the swimming direction and tidal current direction. Moving distance during 5 minutes (5MD) during pile driving and finishing operations between rock surface and bedrock were 0.94-0.96 times (76.0-77.0 m) and 1.81-2.73 times (146.0-219.5 m), respectively, compared with no pile driving. This study is expected to be used as a basic data of fish behavior research on underwater noise.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.44 no.6
• /
• pp.1224-1239
• /
• 2020

This study develops a wearable solar energy harvesting device that absorbs solar energy to generate and store power which can be used during outdoor activities by users even after dark. For this study, a prototype hat for outdoor activities at night was developed after the design of a solar energy harvesting generation, storage, and delivery system was designed that could store energy to light up LEDs. First, the main control board of the system was designed to integrate the charging function, the darkness detection circuit, the battery voltage sensing circuit, and the LED driving circuit in order to reduce bulkiness and minimize the connection structure. It was designed to increase convenience. Second, the system was designed as a wearable fashion product that connected each part with fiber bands and manufacturing it so as to be detachable from the hat. Third, charging and LED operation tests show that the battery is fully charged after 5 hours even in winter when the illuminance value is low. In addition, the LED operation experiment verified the effectiveness of a buffered system that could operate the LEDs for about 3 hours at night.

• Journal of Korea Port Economic Association
• /
• v.20 no.2
• /
• pp.19-33
• /
• 2004

Recognizing that the main container ports' status is gradually inclining, the Japanese government is driving forward the super hub port project. This project has three goals, unifying Japanese ports separating nationally, diminishing the port costs by 30 percents less than the current port costs of their competitors, and cutting down the lead time of processing import-export freight into 24 hours, Singaporean level. The project will work to some extent, if succeeding, but the effect is doubtful if it will be the fundamental solution of Japanese ports' crisis. I wrote this paper since I thought that this Japanese policy would serve as a good reference of Korea, which had two container ports system and its prospect was not good through the fact that the Busan ports' rank of dealing with containers fell down to the fifth in 2003.

• Journal of Environmental Science International
• /
• v.8 no.2
• /
• pp.145-150
• /
• 1999

To estimate the thermal effect of the vegetation canopy on the surface sublayer environment numerically, we used the combined model of Pielke's1) single layer model for vegetation and Deardorff's2) Force restore method(FRM) for soil layer. Application of present combined model to three surface conditions, ie., unsaturated bare soil, saturated bare soil and saturated vegetation canopy, showed followings; The diurnal temperature range of saturated vegetation canopy is only 20K, while saturated bare soil and unsaturated bare soil surface are 30K, 35K, respectively. The maximum temperature of vegetation canopy occurs at noon, about 2 hours earlier than that of the non-vegetation cases. The peak latent heat fluxes of vegetation canopy is simulated as a 600Wm-2 at 1300 LST. They have higher values during afternoon than beforenoon. Furthermore, the energy redistribution ratios to latent heat fluxes also increased in the late afternoon. Therefore, oasis effect driving from the vegetation canopy is reinforced during late afternoon compared with the non-vegetated conditions.

• Journal of Environmental Health Sciences
• /
• v.17 no.2
• /
• pp.9-16
• /
• 1991

Personal NO$_{2}$ expousre and time activity patterns were measured during March, 1991 for 46 taxi drivers in the Seoul area. Badge-type personal samplers were worn for 24 hours by taxidrivers for monitoring personal expousre to NO$_{2}$. A standard respiratory questionnaire was administered and pulmonary function test was performed using a protable spirometry. The mean concentrations of personal NO$_{2}$ expousres of taxi drivers were 0.55ppm. Personal NO$_{2}$ exposures of taxi drivers were seemed to be higher in longer period of driving, smokers, and use of LP gas in homes. Prevalence rate of respiratory symptoms and the level of pulmonary function(FEV$_{1.0}$ and FVC) seemed to be related to higher personal NO$_{2}$ concentrations. It is concluded that persoanl NO$_{2}$ expousres of taxi drivers are probably affected by indoor NO$_{2}$ levels of a tax/and their common activities.

• Proceedings of the KIEE Conference
• /
• 1993.11a
• /
• pp.9-12
• /
• 1993

This study investigated the propriety and the extension of the term of validity about the using watthour meters at present. The subject of study is 1Cent 2W 220V 30(10)A, 1Cent 3W 110V 30(10)A of model III watthour meters. They are the used metes(products in 1984) and the repaired meters(products in 1977) in the end of the period. The investigation is as follows. o Investigation of external appearance o Driving current test o Creeping test o Noise test o Error test o Durability test. Results of the study have been the number of 13.3% exceeded permitting error and the number of 31.3% failed in endurable test of 500 hours. So, the using meters are not suitable to extend the term of validity without the improvement of several characteristics.

• Proceedings of the IEEK Conference
• /
• 2008.06a
• /
• pp.131-132
• /
• 2008

It is necessary to develop a high-speed wireless transmission system, which is able to send medical informations to the emergency medical center during emergency patient transportation. In this research, a system which transmits patient’s vital signs and a real-time audio/video contents of the event has been designed, developed, and the suitability of the system has been verified. Test results indicate that the system is capable of transmitting vital signal data, including 17 numeric data, 12 waveforms and 113 events, reading the affected part by forwarding a $320{\times}240$ pixel image at 2fps. Also, the full-duplex voice transmission of the system at 8bit/64kbps is enough to make stable communication between emergency medical technicians and hospital professionals possible. After numerous hours of driving, the packet loss of patient vital signs is 0.013%.