• Convergence Security Journal
• /
• v.18 no.5_1
• /
• pp.45-51
• /
• 2018

As data utilization and importance becomes important, data-related accidents and damages are gradually increasing. Especially, insider threats are the most harmful threats. And these insider threats are difficult to detect by traditional security systems, so rule-based abnormal behavior detection method has been widely used. However, it has a lack of adapting flexibly to changes in new attacks and new environments. Therefore, in this paper, we propose an adaptive anomaly movement detection framework based on a statistical Markov model to detect insider threats in advance. This is designed to minimize false positive rate and false negative rate by adopting environment factors that directly influence the behavior, and learning data based on statistical Markov model. In the experimentation, the framework shows good performance with a high F2-score of 0.92 and suspicious behavior detection, which seen as a normal behavior usually. It is also extendable to detect various types of suspicious activities by applying multiple modeling algorithms based on statistical learning and environment factors.

• Fire Science and Engineering
• /
• v.33 no.1
• /
• pp.23-29
• /
• 2019

Rechargeable battery such as lithium-ion battery has been noticed as a kinds of the energy storage system in the recent energy utilization and widely used actually in various small electronic equipment and electric vehicles. However, many thermal runaway caused battery accidents occurred recently, which still is obstacle for advanced application of lithium ion battery. One of the main differences to general fires is the existence of ionized electrolyte with electron during combustion. Therefore, we simply simulated the ion addition effects of battery fires by introducing an ionized fuel in jet diffusion flames. When the ionized methane through a corona discharge was used as fuel, the overall flame stability and shape such as flame length showed no significant difference from normal methane flame, but NOx and CO emissions measured at the post flame region decreased. The ion addition effect of methane oxidation was also numerically simulated with the modeling of hydrogen addition in the mixture. It was confirmed that the hydrogen addition at a fixed temperature had a similar effects on ionization of methane and hence could be modeled successfully.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.18 no.3
• /
• pp.84-94
• /
• 2019

This paper developed the VSL control algorithms for various traffic conditions in tunnels. Various algorithms determining control speed, buffer speed, and display time were suggested in order to apply three gantry locations. The algorithms were evaluated by constructing simulation environments using python and VISSIM Com-Interface. Results show that speed difference between congested flow and normal flow was 50 km/h without algorithm application, but the difference was reduced to 20 km/h with algorithm application. In addition, the length of congested region in the exit section of the tunnel was also reduced from 800m to 300m with algorithm application. It is expected that the traffic accidents in tunnels may be reduced since the average and standard deviation of the speed are greatly reduced after applying the algorithms suggested.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.18 no.6
• /
• pp.181-186
• /
• 2018

With progress in industrialization, facilities for generating, delivering, and receiving high levels of electric power are in great demand. The scale of electric power equipment is increasing in both size and complexity. This has contributed to the development of our modern, high-tech and information-based society. However, if the generation of electric power is suspended due to unexpected accidents at power facilities or power stations, a range of equipment the operations of which are dependent on electric power can be damaged, causing substantial socioeconomic losses in an industrial society. A great deal of time and money would be expended to repair damaged facilities at a power station, causing enormous economic loss. In order to detect the deterioration processes of power cables, and to prevent the destruction of power cables, the operation status of power cables should be monitored on a regular basis. We studied the method in order to improve accuracy and reliability for diagnosising the junction where accident occurs frequently. We present the method of data acquisition and statistical processing.

• The Journal of Korean Obstetrics and Gynecology
• /
• v.34 no.4
• /
• pp.111-130
• /
• 2021

Objectives: The purpose of this study was to identify the current status of Korean medicine clinical practice for pregnant patients. Methods: The study is conducted by searching medical records of 209 pregnant patients using Korean Standard Classification of Diseases related pregnancy at the Korean Gynecology Clinic of traditional Korean medicine hospital from March 1, 2016 to February 28, 2021. We retrospectively investigated characteristics, symptoms, pregnancy outcomes of the patients and treatments for the patients. Results: The most frequent symptoms of pregnant patients were musculoskeletal symptoms (60.63%) followed by neuropsychiatric symptoms (14.55%) and genital symptoms (10.82%). The most common contributory factor of the symptoms was the motor vehicle accident (74.64%). Acupuncture (94.94%) and moxibustion (90.91%) were performed to most pregnant patients. Cupping (86.60%), herbal medicine (52.63%), Chuna therapy (30.62%), and pharmacopuncture (21.05%) were performed to the patients. Normal pregnancy maintenance and delivery were reported by 147 patients (91.30%). Premature birth was reported by 11 patients (6.83%), and miscarriage was reported by 3 patients (1.86%). Conclusions: Most patients were the patients with musculoskeletal symptoms injured by motor vehicle accidents. Various Korean medicine treatments were performed during pregnancy with safety outcomes. This study could be used as basic data to provide instructions for the development of traditional Korean medicine in the obstetric clinical fields.

• Korean Chemical Engineering Research
• /
• v.60 no.2
• /
• pp.223-228
• /
• 2022

In chemical processes, unintended faults can make serious accidents. To tackle them, proper fault diagnosis models should be designed to identify the root cause of faults. To design a fault diagnosis model, a process and its data should be analyzed. However, most previous researches in the field of fault diagnosis just handle the data set of benchmark processes simulated on commercial programs. It indicates that it is really hard to get fresh data sets on real processes. In this study, real faulty conditions of an industrial polystyrene process are tested. In this process, a runaway reaction occurred and this caused a large loss since operators were late aware of the occurrence of this accident. To design a proper fault diagnosis model, we analyzed this process and a real accident data set. At first, a mode classification model based on support vector machine (SVM) was trained and principal component analysis (PCA) model for each mode was constructed under normal operation conditions. The results show that a proposed model can quickly diagnose the occurrence of a fault and they indicate that this model is able to reduce the potential loss.

• Nuclear Engineering and Technology
• /
• v.55 no.7
• /
• pp.2388-2394
• /
• 2023

The radioactivity concentration of environmental radionuclides was analyzed for soil and sand at eight locations within a radius of 255 m centered on the Dongnam Institute of Radiological & Medical Science (DIRAMS), Korea. The average activity concentrations of ⁴⁰K, ¹³⁷Cs, ²²⁶Ra, and ²³²Th were 661.1 Bq/kg-dry, 0.9 Bq/kg-dry, 21.9 Bq/kg-dry, and 11.1 Bq/kg-dry, respectively. The activity of ⁴⁰K and ¹³⁷Cs was lower than the 3-year (2017-2019) average reported by the Korea Institute of Nuclear Safety, respectively. Due to the nature of granite-rich soil, the radioactivity of ⁴⁰K was 0.6-fold higher than in other countries, while ¹³⁷Cs was in the normal fluctuation range (15-30 Bq/kg-dry) of the concentration of radioactive fallout from nuclear tests. The activity of ²²⁶Ra and ²³²Th was lower than in Korean soils reported by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). The average activity concentrations of ²³²Th and ⁴⁰K for the soil and sand samples from DIRAMS were within the range specified by UNSCEAR in 2000. The radium equivalent activity and internal and external hazard index values were below the recommended limits (1 mSv/y). These radionuclide concentration (²²⁶Ra, ²³²Th, ⁴⁰K, and ¹³⁷Cs) data can be used for regional environmental monitoring and ecological impact assessments of nuclear power plant accidents.

• Korean Journal of Culture and Social Issue
• /
• v.12 no.4
• /
• pp.77-99
• /
• 2006

The purpose of this study was to find out the effects of auto-mobile tinting upon driver's cognitive responses and behaviors through two laboratory experiments, a field experiment and a traffic accident data. The results of two laboratory experiments showed that there were higher false alarm responses under the conditions of 65%, 50%, 35% tinting level than thoses under the 100% level condition. It was also shown that the drivers who had bad sight made more missing responses than the drivers who had normal vision. The main results of the laboratory experiment were repliceted through both the field experiment and the survey research of car accidents. The results of this study were discussed in terms of the previous studies performed abroad. We strongly suggested 70% tinting level as a regulation standard for safe driving and the strategies for implementing the regulation rule.

• Journal of the Society of Naval Architects of Korea
• /
• v.60 no.6
• /
• pp.424-432
• /
• 2023

This study deals with the design of a safety device around a leisure boat propeller. The safety device is to be designed to minimize performance degradation attached to propulsors in coastal waters. These devices, important for preventing propeller accidents, negatively gives influence boat performance, especially at higher speeds. In order to minimize the negative effect, the accelerating ducts, normally used in ESDs (Energy Saving Devices) have been chosen as a safety device. The present study aims to design an optimal duct (minimizing negative effect) through the parametric study. Based on the Marine 19A nozzle, the nozzle's thickness and angle were varied to obtain the optimum parameter in the preliminary design by the computational fluid dynamics program Star-CCM+ Ver. 15.02. In the detailed design, a NACA 4-digit Airfoil shape resembling the Marine 19A by modification at the trailing edge was chosen and the optimum shape was chosen according to variation of camber, thickness, and incidence angle for optimization. The optimally designed duct shows a speed decrease of about 10% in the sea trial result, which is much smaller than the normal speed decrease of at least 30%. The present designing method can give wide applications to the leisure boat because the wake is almost the same due to using the outboard propulsor.

• Journal of Korea Society of Industrial Information Systems
• /
• v.28 no.6
• /
• pp.1-10
• /
• 2023

The nuclear power plant(NPP)'s Instrumentation and Control(I&C) system periodically conducts integrity checks for the maintenance of self-diagnostic function during normal operation. Additionally, it performs functionality and performance checks during planned preventive maintenance periods. However, there is a need for technological development to diagnose failures and prevent accidents in advance. In this paper, we studied methods for estimating the reliability function by utilizing environmental data and self-diagnostic data of the I&C equipment. To obtain failure data, we assumed probability distributions for component features of the I&C equipment and generated virtual failure data. Using this failure data, we estimated the reliability function using representative artificial intelligence(AI) models used in survival analysis(DeepSurve, DeepHit). And we also estimated the reliability function through the Cox regression model of the traditional semi-parametric method. We confirmed the feasibility through the residual lifetime calculations based on environmental and diagnostic data.