• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.4
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• pp.38-44
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• 2011

Grounding electrodes with higher burial depths are evaluated to have better performance, due to the domestic practice that puts the grounding resistance as the standard of performance evaluation, while grounding resistance decreases as the burial depth increases. However, The dangerous voltage is necessary for the analysis. Because the performance evaluation of grounding electrodes should include not only grounding resistance but also the dangerous voltage(mesh voltage and step voltage). So in this paper, The dangerous voltages of mesh grounding and rod grounding were analyzed for using computer simulation and miniature grounding model.

• Journal of the Optical Society of Korea
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• v.14 no.4
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• pp.451-457
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• 2010

Increasing demands on the safety of public train services have led to the development of various types of security monitoring systems. Most of the surveillance systems are focused on the estimation of crowd level in the platform, thereby yielding too many false alarms. In this paper, we present a novel security monitoring system to detect critically dangerous situations such as when a passenger falls from the station platform, or when a passenger walks on the rail tracks. The method is composed of two stages of detecting dangerous situations. Objects falling over to the dangerous zone are detected by motion tracking. 3D depth information retrieved by the stereo vision is used to confirm fallen events. Experimental results show that virtually no error of either false positive or false negative is found while providing highly reliable detection performance. Since stereo matching is performed on a local image only when potentially dangerous situations are found; real-time operation is feasible without using dedicated hardware.

• Journal of Pharmacopuncture
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• v.17 no.1
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• pp.70-73
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• 2014

Objectives: Yamen is the fifteenth acupoint of the Governor Vessel Meridian (GV15). It is anatomically close to the medulla oblongata, so finding the safety depth of the acupoint is very important. However, few studies on the safety depth of GV15 have been done. Methods: This study tried to measure the safety depth of GV15 by using magnetic resonance imaging (MRI) scans and to analyze the factors affecting the safety depth through multiple regression analyses. This study was carried out for patients who had a brain MRI scan while visiting Jeonju Wonkwang Hospital, Korea. The shortest distance between the glabella and the occipital protuberance (DGO), the horizontal distance between the glabella and the back of the head (DGB) and the dangerous depth (DD) were measured from the sagittal views of the MRI images. The DD is the horizontal distance from the skin's surface at GV15 to the spinal dura mater. Results: The model suggested that the safety depth (SD) was significantly associated with gender (${\beta}$ = 0.474, P < 0.0001), DGO (${\beta}$ = 0.272, P = 0.027), and BMI (${\beta}$ = 0.249, P = 0.005) and the combination of three variables can explain the SD, with $R^2$ = 0.571 (Table 3). A longer SD was associated with males and with greater BMI and DGO. Conclusion: This study suggests that gender, BMI and DGO may be important factors when the SD of GV15 is considered clinically through a multiple regression analysis of GV15.

• Journal of the Korean Society of Marine Environment & Safety
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• v.6 no.1
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• pp.77-83
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• 2000

En coastal area, many submarine facilities such as pipes and cables are installed on/under the sea bed. Also, there are heavy traffic due to numerous vessels which call in ports or navigate passages in adjacent water. Therefore, the frequency of dropping anchors will be increased to avoid various dangerous situations. When an anchor is dropped from vessel on the sea bed, the anchor strikes on the sea bed, and then, the anchor penetrates to certain depth into the sea bed. In this case, sometimes submarine facilities on/under the sea bed may be damaged by the strike or the maximum penetrating depth of anchor. In this paper, some approximate equations on the strike and the penetrating depth of anchors have been derived on the basis of actual data, and the results are expected to use as basic design data of related facilities.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.1
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• pp.61-67
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• 2021

With the recent development of bathemetry technology, the hydrographic surveying method has been changed from single beam depth device use to multi beam acoustic sounding technology. Also, various studies have been reported to obtain high accuracy and precision in the process of river bed topographic data. Especially south korea is geographically on three sides of the sea and the river topography is very developed. To build information about the underwater, and riverbed status, the public investigations has been continuously progressed. In this study, We investigasted the riverbed topography near Baeckma river leisure park. for this purpose, In this study, as the first preliminary survey, location of navigational dangerous objects and reefs and the dangerous areas are identified. Also, ground control points is selected for the optimal GPS surveying. Secondary, through test surveying the Gain, TVG, and pulse length are determined. In addition, the investigation of dangerous objects for navigation is also conducted. As the last step, the error analysis are conducted for the acquired data, and this process involves the removal and adjustments of errors. This section includes the analysis of tide level and navigational contributions, and finally generates a submarine topographic map.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.265-270
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• 2007

The potential and step voltage distribution around low voltage joint-box cover were simulated with the variation of resistivity of water, depth of submerged water and point of leakage current. The potential distribution is very high gradient around low voltage joint-box, this condition is very dangerous states.

• Journal of the Korea Convergence Society
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• v.9 no.10
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• pp.61-67
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• 2018

This study covers the results obtained after three years of development work of real - time gas safety monitoring app. In order to reduce the risk of accidents in the gas workplace, it is essential to provide information so that operators can recognize the location of dangerous substances, dangerous facilities, safety procedures, and the temperature and humidity of the workplace. Therefore, this study was conducted to develop a monitoring app that allows the main system to efficiently receive the information in the field where the information is continuously updated. As a result of quantitative and qualitative research and analysis on app scenarios based on the research done in the past and web screen of the main system, it was modified and improved in terms of ease of use, readability, and intuitiveness. Especially, we made many improvements at low depth, which is a sub-area of ease of use. As a result of conducting a user satisfaction survey on the finally derived app scenarios, the average score of 98.5 was obtained in terms of functionality, convenience and readability.

• Journal of Korean Elementary Science Education
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• v.27 no.2
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• pp.117-133
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• 2008

The purpose of this study was to investigate the elementary students' views about lab-based science learning. For the purpose of this study, semi-structured interviews were conducted with thirty sixth grade students in 12 classes from two elementary schools located in Daegu City. The interview contents consisted of three major categories. The first category was related to attitude toward science lab, the second was related to lab-based science learning which had four sub-categories; recognizing lesson object, planning experiment, performing experiment, drawing conclusion in lab-based science learning in which the students had ordinary have views and expectations, and the last category was related to students' difficulties and something need to be improved in lab-based science learning. In-depth interviews were performed individually and the interviews were recorded. From the interviews, we found that students, in first category, do like lab-activities more than lectures or instruction-based activities in textbook. Students, in second category, wanted generally more discussion for their own activities rather than teacher's instruction and they wanted teacher' mediation conflicts within small groups and comments for students' experiment results. In the last, most of students had fears for some dangerous reagents and accidents. Based on the results, the study suggested that teacher need to give their students to autonomous discussion opportunities to design and interpret data through teacher' guided questions in inquiry steps, to produce some intimate atmosphere for active interaction in small groups, and to teach the safety education on some dangerous reagents.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.15 no.1
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• pp.75-80
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• 1997

In other to construct a subway, we have to consider the position of the subway and acquisition of a topography, profile-map, cross-map, underground facilities map. All information of underground is demanded accurate location in other to prevent of accident of underground in subway construction. We must think about water lines, sewer lines, electronic lines, telephone lines, all urban gas-line because these are needed construction the subway. And attributes of underground facilities recorded on topography are characteristics. length, width. number, position, and depth of the lines. We have to record these attributes because these are very important to design map on subway construction. If we develop GIS (Geographic Information System) to use the exact in-formation of the underground facilities, we can be management safely and prevent very dangerous accident as fast as possible. In this study, attribute informations are linked geographic informations about underground facilities and we can develop Underground Facilities Management System(UFMS) to analysis dangerous region through dangerous degreed and predict accident range with these informations.

• Journal of the Korean Society of Safety
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• v.24 no.1
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• pp.89-94
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• 2009

The purpose of this study is to estimate the critical flood discharge and flash flood trigger rainfall for alarm system providing for a flash flood in mountainous area. The flash flood need non-linear approaching method, because rainfall-runoff is nonlinear and it is difficult to explain the existing linear rainfall-runoff. Hydrological characteristics would be utilized to apply such as hydrologic modelling or basin management. This study was effectively estimated a topographic characteristic factor of basin using the GIS. Especially, decided stream order using GIS at stream order decision that is important for input variable of GCIUH. A flash floods defined as a flood which follows shortly after a heavy or excessive rainfall event, with a few hours. In this study, we gave a definition that a critical flood for alarm is the flood when valley depth judging dangerous depth is over 0.5m depth from the bottom of channel. Result that calculate threshold discharge to use GCIUH, at the Mureung valley basin, flash flood trigger rainfall was 16.34mm in the first 20minutes when the threshold discharge was $14.54m^3/sec$.