• Proceedings of the KSR Conference
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• 2010.06a
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• pp.72-79
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• 2010

The significant of continuous welded rail (CWR) management is growing because KORAIL has the plan to convert the whole of conventional railway lines into CWRs through continuous activities since constructed the CWR track with 1.8km in Gyeongbu line in 1966. The CWR recently is needed a efficient management method because it is difficult to manage the CWR by the poor of technic and equipment, limited maintain labor force and shorted the maintain work time of CWR caused by industrialization, greenhouse effect and global warming In this point, The 70ton Tenser's which is using in the rail site has been analysised with no extra tenser's capacity in case of the under low temperature and exceed the length of 1km as a result of reviewing the CWR-related rules and standards, a series of records of safety accidents, operation obstacles, and the situation of broken rails published by KORAIL, existing rail temperature measurements, and CWR researches. Therefore avoid the excessive plan of the first set-up section, choice the proper time in the normal temperature that is possible to weld the rail, turning the difference of rail temperature and Installation temperature down is desirable.

• Fire Science and Engineering
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• v.20 no.3 s.63
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• pp.35-41
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• 2006

In this study, we presented the problems in the insulation cover of 22.9kV transformer bushing through investigating actual conditions. After thermal stress applied to the insulation cover, deterioration patterns, thermogravimetric and infrared characteristics were analyzed, and the results were applied to the cause analysis of accidents and judgement of safety. The insulation covers are used to protect exposed terminals of transformer, but they had improper size and length. Therefore, they could not show efficient insulation function. In case that thermal stress of $150^{\circ}C$ was applied to the insulation covers, plastic insulation covers(A, B, D, E) damaged severely, whereas rubber insulation cover(C) showed normal shapes. In the result of thermogravimetric analysis, the thermal gravity of plastic covers(A) decreased about 33.3% at $307.8^{\circ}C\;to\;405.9^{\circ}C$. and he thermal gravity of rubber covers (C) decreased about 53.7% at $258.8^{\circ}C\;to\;32.9^{\circ}C$. In the result of FT-IR analysis, plastic covers showed peaks characteristic of $CH_2,\;CH_3$, C=O and C=C bonds, whereas rubber covers showed peaks characteristic of OH, $CH_2,\;CH_3$, C=O, C=N and C=C bonds.

• Journal of Oriental Neuropsychiatry
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• v.20 no.2
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• pp.111-120
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• 2009

Objectives : This study was performed to investigate the effects of Needle Electrode Electrical Stimulation (NEES) on ischemia-induced cerebrovascular accidents. After obstruction and reperfusion of ${\ast}{\ast}$ arteries in white mice, the amounts of necrosis and inflammation related substances IL-6, Caspase-3, and PARP, C-fos were measured in neurons of the hippocampus. The following results were obtained. Methods : This study used 21 male specific pathogen free (SPF) SD (Sprague Dawley) rats, 8 weeks of age and approximately 300 g in weight, that were given at least 1 week to adapt to the lab environment Each exposed artery was completely occluded with non-absorbent suture thread and kept in that state for 5 minutes. The sutures were then removed to allow reperfusion of blood. Test group is control group for comparison with the common carotid artery occlusion models, a GI group that underwent common carotid artery occlusion, and a needle electrode electrical stimulation (NEES) group that underwent NEES after artery occlusion. The GI and NEES groups were given 12, 24, or 48 hours of reperfusion before NEES. NEES device (PG6, ITO, Japan, 9V, current, 2Hz) was used to stimulate the right and left acupoint ST36 of the SD rats for 30 minutes while they were sedated with 3% isoflurane. An immunohistochemistry test was done on the forebrains of the GI induced rats. All the data collected from this study was symbolized and analyzed using a statistics processing program (SPSS 12.0K/PC). The level of significance was set at ${\alpha}$=0.05 and a T-TEST analysis was used to find out the effects of treatment on each of the groups: the normal group, the CVA induced group, and the treatment after CVA induction group. Results : Both PARP and C-fos immuno-reactive cells, related to apoptosis, were greater in the GI groups than the NEES group. Caspase and IL-6 immuno-reactive cells, related to inflammation, were greater in the GI and NEES groups than the control group. Conclusions : This research was conducted to study the effects of NEES on CVA due to ischemia. Occlusion and reperfusion was performed on the common carotid arteries of white rats, after which amounts of substances related to neuron necrosis and inflammation - PARP, IL-6, Caspase-3, and C-fos - were measured in the Hippocampus

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.2
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• pp.142-150
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• 2006

PURPOSE : The 3rd molar extraction of mandible is common in out-patient office of oral and maxillofacial surgery. And it is dynamic minor operation with changes of vital signs. most of patients are already sensitive about their dental treatment. The changes of emotion are reached to the highest level when patients is laid down to be treated on unit chair. It can be induced to undesirable accidents as to this fear. The undesirable complications are nausea, vomiting, hyperventilation, dyspnea, syncope, shock and so on. The severe changes of vital signs may influence their behavior and make serious medical malpractice or suit such as fracture of dental instruments and injury of proximal area. METHOD AND PATIENTS : A total of 99 selected normal patients were reviewed. Among this, 70 patients(43 men, 27 women with statistical significance) were included in this study. Each steps(pre-anesthesis, 5 minutes after anesthesis, just after mucogingival incision, just after tooth section, just after suture and gauze biting) were investigated for a change of a vital signs. It is analyzed to 2 categories,"Means" and "Tendency". The "Means" is the amount of vital signs changed in comparison with pre-step during operation. That means is the amount of vital changes by each step operation. Next, " Tendency" is changes of vital signs in comparison with step1 during operation. RESULT : This is the changing tendency of vital signs with time. That is active effect of fear and pain. Thus this "Means" and "Tendency" will present a sudden changes of vital signs and it can lead to more safe treatment. CONCLUSION : Thus, the purpose of this study is, through careful operation in each step, to less on patients' complication and increase trust between patient and OMFS. This study is a first article shown with the amount of "Means" and "Tendency" in vital signs, when a third molar of mandible is extracted. This study will be base study of patients with general diseases, because it selected only patients without general diseases.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.6
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• pp.689-695
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• 2015

The offshore plant crews that were commissioned in the commercial startup phase boarded the offshore plant in two shifts until the end of the project. The crews who were hired by the owner side stayed in the original offshore plant during the project. However, most of the offshore plant commissioned members who were dispatched from the shipyard were accommodated in the offshore accommodation barge. For this reason, they were exposed to many accidents since there are a lot of people staying in a small space. This study suggested a method for improving survival rate at offshore accommodation barge in terms of life safety. It is assumed that the fire accident among unfortunate events which take place in the offshore accommodation barge mainly occurred. So, this study analyzed the safety evacuation for offshore plant employees using fire simulation model based on both domestic and international law criteria. In particular, When fire occurs in the offshore accommodation barge, the periodically well trained crews are followed safety evacuation procedure. whereas many employees who have different background such as various occupations, cultural differences, races and nationality can be commissioned with improper evacuation behaviors. As a result, the risk will be greater than normal situation due to these inappropriate behaviors. Therefore, This study analyzed the Required Safe Escape Time (RSET) and Available Safe Escape Time (ASET). Also it was suggested the improvement of structure design and additional arrangement of safety equipment to improve the survival rate of the residents in offshore accommodation barge.

• Fire Science and Engineering
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• v.33 no.4
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• pp.140-151
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• 2019

It is to assess the indoor air quality of the chemical hazardous materials exposed to the fire after firefighters returned to the fire scene. The research subject randomly selected four fire stations located in Seoul, Korea. Two fire stations were set up as control groups after the return of the firefighting activities at the actual fire scene, and two other fire stations were set up as control groups to measure the air quality of the room at normal levels regardless of the action. We conducted 24-hour monitoring for all fire accidents that occurred in Seoul Metropolitan using fire safety map computer system. Also, indoor air quality was measured immediately after homecoming if the experiment group was to be dispatched due to an accident of intermediate or larger scale. 11 hazardous substance items such as fine dust, formaldehyde, volatile organic compounds, PAH, VCM, acidity, asbestos, CO₂, NO₂, O₃ were measured according to the process test method. Three of 11 types of harmful substances exceeded domestic and foreign standards, and one of them was found to be close to foreign standards. In particular, total volatile organic compounds, carbon dioxide and sulfuric acids were 2.5 times, 2.2 times and 1.1 times higher than the standard. Also, for formaldehyde and sulfuric acid, it was measured higher in the control group than in the case group. This findings could be used in policies to improve indoor air quality in the fire station of the Seoul Metropolitan Government.

• Journal of the Korean Society for Railway
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• v.20 no.4
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• pp.491-499
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• 2017

Railway turnout systems are one of the most important systems in a railway and abnormal turnout systems can cause serious accidents. To detect an abnormal state of a turnout, turnout clearance detectors are widely used. These devices consider a failure of a turnout clearance detectors to be a failure of the turnout system, that could hinder train operations. Analysis of turnout clearance detector failures is very important to ensure normal train operation. We categorized failures of detectors into four groups to identify failure characteristics of the 140 detectors, which are composed of main line detectors (A), side tracks (B), detectors that are in operation more than 80 times a day (C) and detectors that are in operation fewer than 10 times per day. Failures of detectors have mainly been caused in the control part, in the cables and sensors; failures are classified into four groups (A, B, C and D). We have tried to find failure density distributions for each type of failures, inferring the parameter distributions a priori. Finally, using the Bayesian inference we proposed a maintenance time for control parts through the mean time of the detector, life and the life expectancy.

• Fire Science and Engineering
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• v.34 no.3
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• pp.67-75
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• 2020

In this study, the risk of heat generation due to normal and overload currents that vary with the abnormal loosening angle of wire-connecting bolts were identified. The risks were analyzed based on the thermal characteristics to minimize the carbonization accidents of terminal blocks inside distribution panels typically used in industrial sites. We applied a method for measuring the heating temperature and temperature variations in the terminal blocks in real-time by installing a resistance temperature detector sensor board in the terminal block. The experimental results showed that the terminal block model with a low-rated current exhibited a higher heating temperature, thus, confirming the need to select the terminal block capacity based on load currents. Additionally, the higher the rated current of the terminal block with a high-rated current and the higher the degree of loosening, the faster the carbonization point. Such heating temperature monitoring enabled real-time thermal temperature measurement and a step-by-step risk level setting through thermal analysis. The results of the measurement and analysis of carbonization risks can provide a theoretical basis for further research regarding the risk of fire due to carbonization. Furthermore, the deterioration measurement method using the temperature sensor board developed in this study is widely applicable to prevent fires caused by poor electrical contact as well as risk-level management.

• Journal of Navigation and Port Research
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• v.33 no.3
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• pp.181-191
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• 2009

In general, seafarer's human error is considered to be the preponderant muse for the majority of maritime transportation accidents in a merchant ship. The implementation techniques for Human Error Model (HEM) to assess possible accident risk by deck officers including captain, chief officer, second mate and third mate are described in this study. The scope of this work is focused to 642 deck officers in the ship management company with 130 vessels. At first, HEM can be constructed through the statistical analysis and expert's brainstorming process with human data to 642 deck officers. Then the variables $\upsilon$ for the human factors, the evaluation level EP($\upsilon$) for $\upsilon$, the weight $\alpha$ of $\upsilon$, and the title weight $\beta$ of each deck officers can be decided. In addition, through the analysis of ship's accident history, the accident causation ratios by human error ${\gamma}_H$ and by external error ${\gamma}_B$ can be found as 0.517(51.7%) and 0.483(48.3%), respectively. The correlation coefficients to $\upsilon$ are also shown significant for a 95% confidence interval (p < 0.05) for each coefficient. And the validity of HEM is also surveyed by the analysis of normal probability distribution of risk level RL to each deck officer.

• KIPS Transactions on Computer and Communication Systems
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• v.1 no.2
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• pp.71-78
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• 2012

The digital tachograph is a device that automatically records speed and distance of a vehicle, together with the driver's activity and vehicle status at an accident. It records vehicle speed, break status, acceleration, engine RPM, longitude and latitude of GPS, accumulated distance, and so on. European Commission regulation made digital tachographs mandatory for all trucks from 2005. Republic of Korea made digital tachographs mandatory for all new business vehicles from 2011 and is widening the range of vehicles that must install digital tachographs year by year. This device is used to analyze driver's daily driving information and car accidents. Under a car accident that makes the device reliability unpredictable, it is very important to store driving information with maximum reliability for its original mission. We designed and implemented a practical digital tachograph. This paper presents a storage scheme that consists of a first storage device with small capacity at a high reliability and a second storage device with large capacity at a low cost in order to reliably records data with a hardware at a low cost. The first storage device records data in a SLC NAND flash memory in a log-structured style. We present a reverse partial scan that overcomes the slow scan time of log-structured storages at the boot stage. The scheme reduced the scan time of the first storage device by 1/50. In addition, our design includes a scheme that fast stores data at a moment of accident by 1/20 of data transfer time of a normal method.