• Journal of the Korean Institute of Gas
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• v.25 no.6
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• pp.7-13
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• 2021

Various research has been done on fires and explosions at gas stations at home and abroad. However, only studies of off-site damage in the event of fire at the gas station were conducted, and research on fire at the auxiliary facilities in the gas station was insufficient. The gas station is a place where anyone can easily access dangerous goods. As the risk of fire increases due to the recent increase of auxiliary facilities such as convenience stores and car repair shops in gas stations, it is important to detect the effects of fire on the main oil refinery in case of fire and to verify the validity of existing regulations. In this thesis, we conducted a study to find out the effect of radiation heat on the separation between fixed and fixed oil reactors in the event of fire at an auxiliary facility. Simulation was modelled using FDS 5.5.3 Version, and the size of the fire source was configured with 13 fire assessment devices and the heat emission rate per unit area was entered. Simulation shows that the separation distance of 2 m does not secure the safety of the gas pump in the event of fire at the auxiliary facilities, and radiation heat does not damage at the separation distance of at least 4 m. Accordingly, facilities that can block radiant heat in the event of fire at auxiliary facilities, and measures to limit the use of auxiliary facilities or to re-impose the separation between buildings and fixtures will be needed.

• The Journal of the Acoustical Society of Korea
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• v.40 no.6
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• pp.615-625
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• 2021

Prior to proposing appropriate standard for subway station platform, this study conducted field measurements to examine characteristics of room acoustics on platform of two subway stations. As a result of analyzing the longitudinal length of the platform, Sound Pressure Level (SPL) decreased (maximum difference : 14 dB), Reverberation Time (RT) tended to increase (maximum difference of 0.8 s ~ 1.5 s), and C50 and D50 were decreased (maximum difference: 5.9 dB ~ 9.1 dB and 31.8 % ~ 37.6 %, respectively) as measurement positions moved away from the sound source. The Interaural Cross-correlation Coefficient (IACC) did not show clear tendency, but it was lower than 0.3 in entire points. It is judged that the subway platform has non-uniform sound field characteristics due to various combinations of direct and reflective sound even though it is finished with a strong reflective material.This indicates that the room acoustic characteristics of the near and far sound field are clearly expressed depending on the source-receiver distances in the subway platform having a long flat shape with a low height compared to the length.Therefore, detailed architectural and electric acoustic design based on the characteristics of each location of speaker and sound receiver in the platform is required for an acoustic design with clear sound information at all positions of the platform.

• Journal of Industrial Convergence
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• v.21 no.7
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• pp.29-39
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• 2023

In the recent period, there have been numerous earthquakes both domestically and internationally, and buildings in South Korea are particularly vulnerable to seismic design and earthquake damage. Therefore, the objective of this study is to discover an effective method for assessing the seismic vulnerability of buildings and conducting a density analysis of high-risk structures. The aim is to model this approach and validate it using data from pilot area(Seoul). To achieve this, two modeling techniques were employed, of which the predictive accuracy of the statistical analysis technique was 87%. Among the machine learning techniques, Random Forest Model exhibited the highest predictive accuracy, and the accuracy of the model on the Test Set was determined to be 97.1%. As a result of the analysis, the district rating revealed that Gwangjin-gu and Songpa-gu were relatively at higher risk, and the density analysis of at-risk buildings predicted that Seocho-gu, Gwanak-gu, and Gangseo-gu were relatively at higher risk. Finally, the result of the statistical analysis technique was predicted as more dangerous than those of the machine learning technique. However, considering that about 18.9% of the buildings in Seoul are designed to withstand the Seismic intensity of 6.5 (MMI), which is the standard for seismic-resistant design in South Korea, the result of the machine learning technique was predicted to be more accurate. The current research is limited in that it only considers buildings without taking into account factors such as population density, police stations, and fire stations. Considering these limitations in future studies would lead to more comprehensive and valuable research.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.4
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• pp.406-412
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• 2009

In this work, a new method to obtain the effective ground conductivity value in the middle frequency band where the informations of soil characteristics are insufficient was proposed. The proposed method obtained the effective ground conductivity values with the measured field strength from sea reference stations and general attenuation model in the middle frequency band. In addition, the proposed method used statistical method to minimize the error between the measurements and the predictions. Then, the effective ground conductivity in Korea peninsular was obtained by using the proposed method. Finally, it was verified that the effective ground conductivity using the proposed method is useful to predict electric field strength in the middle frequency band.

• Journal of the Korea Society of Computer and Information
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• v.17 no.8
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• pp.41-50
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• 2012

Most of the developed countries and Korea have continued to invest much money in developing low-carbon vehicles such as electric car, methanol car and hydrogen car to replace the conventional fossil fuel vehicles. Government and local governments of each country, however, grope to construct roads for bicycle and public bicycle rental systems because bicycle is the only ultimate and feasible non-pollution transportation. Most of the current bicycle monitoring systems have achieved automation of rental process in bicycle stations, but they can not monitor bicycles in use. This paper develops GPS-CDMA modem combined terminals and implements a LBS-based bicycle monitoring system using them for public bicycle rental system. The monitoring system collects location information from GPS-CDMA modem combined terminals attached on bicycles and presents the moving tracks of bicycles on a GIS map for easy return and redistribution of bicycles. Also, the system helps to prevent from theft and vandalism of bicycles and to recommend the nearest bicycle station.

• Resources Recycling
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• v.10 no.3
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• pp.14-22
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• 2001

For the recycle of coal fly ash generated from power stations, we developed an electrocyclone system which can separate unburned carbon form coal fly ash, based on the fact that coarse fly ash particles contain higher amount of unburned carbon and unburned carbon particles are charged positively, and pure ash particles are charged negatively on contacting each other. Additionally, guide vanes were installed in the cyclone to control the cut size. Two types of electrode, stick and grid type, were designed to investigate the effect of electrode type. Results show that by introducing an electric field inside the cyclone, the yield increases by 5 to 15e1o. But the content of unburned carbon in the clean ash does not change significantly.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.1
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• pp.44-57
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• 2013

In this paper, we propose a femtocell searching technique which can prevent a macrocell UE(user equipment) from losing synchronism to its serving macrocell near closed access femtocells in co-channel deployment due to the leakage of femtocell signals by using a CS(Common Signal). The CS, commonly transmitted by femtocells in a macrocell at the same time, enables the macrocell UEs to be kept synchronized with their serving macrocells since the CINR(Carrier to Interference and Noise Ratio) of base stations in macrocell can be kept high even near closed access femtocells. Also, the CS is designed in such a way that a macrocell UE can recognize the existence of femtocell by using the metric CSCINR(Common Signal Carrier to Interference and Ratio) measured with CS. In addition, the proposed femtocell searching technique can reduce the frequency of femtocell searching trial by using the metric on mobility of a macrocell UE defined in this paper, and the reduction of the frequency of handover trial can be also expected as a byproduct.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.5
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• pp.179-184
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• 2016

The usual way used by electric power stations to deliver high levels of generated power is via 6.6kV XLPE (or CV) cables. Depending on the manufacturing technique, installation environment, and usage conditions, the deterioration processes of the power cables start from the instant of operation. Cable junctions may break down in three years from the start of operation due to the manufacturing or construction defects. Otherwise they should be in good working order for 20-30 years. When the cable system (the cable itself and cable junctions combined) deteriorates, fire accidents happen due to the dielectric breakdowns. We have invented a device to monitor the deteriorating status of cables at Korean Western Power Co. Ltd. located in Taean, Chungcheongnam-do province. In this paper, we introduce the device hardware. Using the device, we have measured the insulation resistance and humidity in the sheath of the cables. We present, in analysed results, the effect of humidity on insulation resistance in cable sheaths.

• Journal of Navigation and Port Research
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• v.33 no.6
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• pp.457-462
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• 2009

In this paper we suggest optimal positioning algorithm for DER(distributed energy resource)s near ocean side by using Newton-Rhapson load flow calculation. By installing DERs within urban area, electric power can be effectively transmitted to each loads without constructing additional large scale power stations and transmission lines. Therefore, DERs have attracted worldwide attention as urban area energy sources. However, there are quite a few studies for estimation of power loss due to DERs' location change within urban area Hence, in this study, an optimal positioning scheme for DERs is proposed in order to minimizing electrical power loss.

• The Transactions of the Korea Information Processing Society
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• v.6 no.8
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• pp.2262-2270
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• 1999

In this paper, we describe gesture recognition algorithm using computer vision sensor and HMM. The automatic hand region extraction has been proposed for initializing the tracking of the tele-operation gestures. For this, distance informations(disparity map) as results of stereo matching of initial left and right images are employed to isolate the hand region from a scene. PDOE(positive difference of edges) feature images adapted here have been found to be robust against noise and background brightness. The KNU/KAERI(K/K) gesture instruction set is defined for tele-operation in atomic electric power stations. The composite recognition model constructed by concatenating three gesture instruction models including pre-orders, basic orders, and post-orders has been proposed and identified by discrete HMM. Our experimental results showed that consecutive orders composed of more than two ones are correctly recognized at the rate of above 97%.