• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.6
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• pp.841-851
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• 2019

This study presents risk ranking by accident types at intersections, crosswalk and tunnel sections. An ordered logit model was used to estimate the accident severity of traffic accidents based on 58,868 accident records that have occurred on the Seoul and Gyeonggi-do over the period 2014-2017. The factors affecting the injury severity were identified by the estimated model first, and risk ranking was proposed according to conditions of accident occurrence using relative ratio analysis later. The analysis results showed that the injury severity dramatically depends on the location and time of the accident. The analysis results showed that the injury severity dramatically depends on the location and time of the accident. Furthermore, there are severe injury cases in terms of the injury severity despite the small number of occurrence of traffic accident, or there are severe injury cases in terms of the injury severity despite the high frequency of occurrence of traffic accident.

• Journal of Korean Neurosurgical Society
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• v.63 no.5
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• pp.631-639
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• 2020

Objective : Traditionally, staged surgery has been preferred in the treatment of compound comminuted depressed fracture (FCCD) after traumatic brain injury (TBI) and involves the removal of primarily damaged bone and subsequent cranioplasty. The main reason for delayed cranioplasty was to reduce the risk of infection-related complications. Here, the author performed immediate reconstruction using a titanium mesh in consecutive patients with FCCD after TBI, reported the surgical results, and reviewed previous studies. Methods : Nineteen consecutive patients who underwent single-stage reconstruction with titanium mesh for FCCD of the skull from April 2014 to June 2018 were retrospectively analyzed. The demographic and radiological characteristics of the patients with FCCD were investigated. The characteristics associated with surgery and outcome were also evaluated. Results : The frequency of TBI in men (94.7%) was significantly higher than that in women. Most FCCDs (73.7%) occurred during work, the rest were caused by traffic accidents. The mean interval between TBI and surgery was 7.0±3.9 hours. The median Glasgow coma scale score was 15 (range, 8-15) at admission and 15 (range, 10-15) at discharge. FCCD was frequently located in the frontal (57.9%) and parietal (31.6%) bones than in other regions. Of the patients with FCCDs in the frontal bone, 62.5% had paranasal sinus injury. There were five patients with fractures of orbital bone, and they were easily reconstructed using titanium mesh. These patients were cosmetically satisfied. Postoperatively, antibiotics were used for an average of 12.6 days. The mean hospital stay was 17.6±7.5 days (range, 8-33). There was no postoperative seizure or complications, such as infection. Conclusion : Immediate bony fragments replacement and reconstruction with reconstruction titanium mesh for FCCD did not increase infectious sequelae, even though FCCD involved sinus. This suggests that immediate single-stage reconstruction with titanium mesh for FCCD is a suitable surgical option with potential benefits in terms of cost-effectiveness, safety, and cosmetic and psychological outcomes.

• The Journal of the Korea Contents Association
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• v.17 no.1
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• pp.50-57
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• 2017

This study investigated the causes and problems of train operation impediments through the statistics analysis of 8 years'internal data of Daejeon Metropolitan Express Transit. By evaluating the risks regarding the system, equipment, and parts of high risk group, this study measured the Risk Index Severity, and applied the $5{\times}5$ Risk Assessment Matrix which is a method of risk management to calculate the scale of risk to analyze the safety level and allowance range. As a result, the car sector, the most serious risk, followed by machinery and equipment sector showed that the inherent risk. In particular, the door broken and the door rail signaling and control devices due to defects of the vehicle is high, but also the severity, and frequency are showing very frequent additional potential accidents. PSD also had defects in the machinery sector appeared to be the most dangerous of the PSD poor safety gates, it was found that the glass also involve the risk of mishandling and breakage of the PSD. This study intended to contribute to the transportation benefits through the safety and stable operation of Metropolitan Express Transit.

• Atmosphere
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• v.22 no.2
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• pp.163-174
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• 2012

Brightness temperature (BT) difference between sea fog and sea surface is small, because the top height of fog is low. Therefore, it is very difficult to detect sea fog with infrared (IR) channels in the nighttime. To overcome this difficulty, we have developed a new algorithm for detection of sea fog that consists in three tests. Firstly, both stratus and sea fog were discriminated from the other clouds by using the difference between BTs $3.7{\mu}m$ and $11{\mu}m$. Secondly, stratus occurring at a level higher than sea fog was removed when the difference between cloud top temperature and sea surface temperature (SST) is smaller than 3 K. In this process, we used daily SST data from AMSR-E microwave measurements that is available even in the presence of cloud. Then, the SST was converted to $11{\mu}m$ BT based on the regressed relationship between AMSR-E SST and MTSAT-1R $11{\mu}m$ BT at 1733 UTC over clear sky regions. Finally, stratus was further removed by using the homogeneity test based on the difference in cloud top texture between sea fog and stratus. Comparison between the retrievals from our algorithm and that from Korea Meteorological Administration (KMA) algorithm, shows that the KMA algorithm often misconceived sea fog as stratus, resulting in underestimating the occurrence of sea fog. Monthly distribution of sea fog over northeast Asia in 2008 was derived from the proposed algorithm. The frequency of sea fog is lowest in winter, and highest in summer especially in June. The seasonality of the sea fog occurrence between East and West Sea was comparable, while it is not clearly identified over South Sea. These results would serve to prevent the possible occurrence of marine accidents associated with sea fog.

• Architectural research
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• v.15 no.3
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• pp.151-158
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• 2013

Offshore oil and gas process plants are exposed to hazardous accidents such as explosion and fire, so that the structural components should resist such accidental loads. Given the possibilities of thousands of different scenarios for the occurrence of an accidental hazard, the best way to predict a reasonable size of a specific accidental load would be the employment of a probabilistic approach. Having the fact that a specific procedure for probabilistic accidental hazard analysis has not yet been established especially for explosion and fire hazards, it is widely accepted that engineers usually take simple and conservative figures in assuming uncertainties inherent in the procedure, resulting either in underestimation or more likely in overestimation in the topside structural design for offshore plants. The variation in the results of a probabilistic approach is determined by the assumptions accepted in the procedures of explosion probability computation, explosion analysis, and structural analysis. A design overpressure load for a sample offshore plant is determined according to the proposed probabilistic approach in this study. CFD analysis results using a Flame Acceleration Simulator, FLACS_v9.1, are utilized to create an overpressure hazard curve. Moreover, the negative impulse and frequency contents of a blast wave are considerably influencing structural responses, but those are completely ignored in a widely used triangular form of blast wave. An idealistic blast wave profile deploying both negative and positive pulses is proposed in this study. A topside process module and piperack with blast wall are 3D FE modeled for structural analysis using LS-DYNA. Three different types of blast wave profiles are applied, two of typical triangular forms having different impulse and the proposed load profile. In conclusion, it is found that a typical triangular blast load leads to overestimation in structural design.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.3
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• pp.705-715
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• 2017

Today, the world is evolving into a huge community that can communicate with real-time information sharing and communication based on the rapid advancement of scientific technology and information. Behind this information, the adverse effects of information assets, such as hacking, viruses, information assets, and unauthorized disclosure of information assets, are continually increasing as a serious social problem. Each time an infringement of the invasion and personal information leaks occur, many regulatory policies have been announced, including stricter regulations for protecting the privacy of the government and establishing comprehensive countermeasures. Also, companies are making various efforts to increase awareness of the importance of information security. Nevertheless, information security accidents like the leaks of industrial secrets are continuously occurring and the frequency is not lessening. In this thesis, I proposed a customized security policy methodology that supports users with various business circumstances and service and also enables them to respond to the security threats more confidently and effectively through not a monotonous and technical but user-centered security policy.

• Journal of the Korea Society of Computer and Information
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• v.18 no.12
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• pp.207-215
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• 2013

The general opinion about the notion of cyberbullying hasn't existed yet, but in related laws it is defined as the entire behavior causing the counterpart to suffer the pain by continuously and repeatedly psychologic offending toward specific students with information and telecommunication products such as the Internet and mobile phones, and spreading the private information or false facts related with specific students. Recently a number of accidents related with abuse of cyberbullying are being broadcast on a variety of mass media, and the argument about the severity and countermeasures against cyberbullying is moving onward. This study has a purpose as suggesting the practical alternatives to prevent cyberbullying victim of middle school students by arguing cyberbullying of middle school students and analyzing the relationship between the general features such as victimized experience and frequency and the emotional behaviors according to victimized experience. As the result of this study, cyberbullying victimized experience has a significant effect on the emotional behavior such as depression, aggression, and academic stress. As political implication, this study suggests the practical alternatives to prevent cyberbullying of middle school students based on the analysis result.

• Journal of the Society of Disaster Information
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• v.18 no.3
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• pp.444-456
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• 2022

Purpose: Laboratories require Preliminary Risk Analysis of Hazard Factors, but there are many laboratories that do not. For the purpose of securing the safety of the laboratory, it is intended to find improvements so that the Risk Assessment can be easily applied. Method: Research papers and data from the Laboratory Safety Management Survey Report by the Ministry of Science and ICT were used. The study was conducted by comparing Preliminary Risk Analysis of Hazard Factors and Risk Assessment under the Occopational Safety and Health Act. Result: A technique for Risk Assessment of a laboratory was proposed. When Risk Assessment of the laboratory, a method was proposed to estimate the size of the possibility(frequency) and severity(intensity). Conclusion: For easy application in the laboratory, a checklist-type Risk Assessment technique was presented and actual evaluation was conducted. It is expected that the laboratory will improve through Risk Assessment to help prevent safety accidents.

• Economic and Environmental Geology
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• v.56 no.5
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• pp.501-514
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• 2023

Forest fires can generate numerous pollutants through the combustion of vegetation and cause serious environmental problems. The global warming and climate change will increase the frequency and scale of forest fires across the world. In Korea, many nuclear power plants (NPPs) are located in the East Coast where large-scale forest fires frequently occur. Therefore, understanding the sorption and transport characteristics of radionuclides in the forest fire areas is required against the severe accidents in NPPs. This article reviewed the physiochemical changes and contamination of groundwater and soil environments after forest fires, and discussed sorption and transport of radionuclides in the subsurface environment of burned forest area. We considered the geochemical factors of subsurface environment changed by forest fire. Moreover, we highlighted the need for studies on changes and contamination of subsurface environments caused by forest fires to understand more specific mechanisms.

• Journal of Biosystems Engineering
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• v.37 no.6
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• pp.352-358
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• 2012

Purpose: The inexpensive black box system was developed to acquire and save driving information, to give the slope information, and to transmit SOS and theft signal. Method: The device consists of a main micro controller to acquire and save data, a GPS sensor module, a CDMA module, a touch LCD module, a RF (Radio Frequency) ID module, a SD (Secure Digital) card module, an emergency electric power source, a theftproof circuit, and a sensing device. The sensing device consists of a 8 bit micro controller, a accelerometer to detect impulse, two slope sensors to detect roll and pitch angle and a circuit to detect operation of 6 lighting devices. Results: Test results are as follows: 1) a tractor can be start up only with an electronic key (password or RFID card), 2) theft signal was transmitted when a tractor moved without an electronic key, 3) SOS was transmitted at conditions that rollover or crash happened. 4) 5 more than per 1s data are recorded at 5 minute intervals as new file name in SD card. Conclusions: This system can be used to save travelling record, reduce accident, prevent theft and rescue life in the accidents.