• Transactions of the Korean hydrogen and new energy society
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• v.25 no.6
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• pp.609-619
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• 2014

In the present study, the frequency of the undesired accident was estimated for a quantitative risk assessment of a large-scale hydrogen liquefaction plant. As a representative example, the hydrogen liquefaction plant located in Ingolstadt, Germany was chosen. From the analysis of the liquefaction process and operating conditions, it was found that a $LH_2$ storage tank was one of the most dangerous facilities. Based on the accident scenarios, frequencies of possible accidents were quantitatively evaluated by using both fault tree analysis and event tree analysis. The overall expected frequency of the loss containment of hydrogen from the $LH_2$ storage tank was $6.83{\times}10^{-1}$times/yr (once per 1.5 years). It showed that only 0.1% of the hydrogen release from the $LH_2$ storage tank occurred instantaneously. Also, the incident outcome frequencies were calculated by multiplying the expected frequencies with the conditional probabilities resulting from the event tree diagram for hydrogen release. The results showed that most of the incident outcomes were dominated by fire, which was 71.8% of the entire accident outcome. The rest of the accident (about 27.7%) might have no effect to the population.

• Nuclear Engineering and Technology
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• v.55 no.1
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• pp.261-269
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• 2023

During a nuclear power plant (NPP) accident, radioactive material may be released into the surrounding environment in the form of a radioactive plume. The behavior of the radioactive plume is influenced by meteorological factors such as wind direction and speed. If the residents are evacuated to a shelter in the direction of the flow of the radioactive plume, the radiation exposure of the residents may increase, contrary to the purpose of the evacuation. To avoid such an undesirable outcome, this paper applies a big data analysis to evaluate the suitability of the shelter locations near 5 NPPs in the Republic of Korea in terms of the seasonal wind direction frequency in those areas. To this end, the wind data measured around the NPPs from 2016 to 2020 were analyzed to derive the seasonal wind direction frequency using a big data analysis. These analyses results were then used to determine how many shelters around NPPs locate in areas with prevailing wind direction per season. Then, suggestions were made on the direction for residents not to evacuate, if possible, that is, the prevailing seasonal wind directions for 5 NPPs, depending on the season in which the accident occurs.

• Journal of Korean Society of Transportation
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• v.29 no.6
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• pp.25-37
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• 2011

This research aimed to investigate whether commercial drivers' situation awareness ability is related to their frequency and magnitude of caused accidents and penalty points. For the purpose of measuring drivers' situation perception and interpretation capacities, two tests named 'situation awareness test' and 'hazard perception test' were developed. The tests were based on the data from 299 commercial drivers (test drivers) using a driving simulator. The outcome of drivers' performance on situation awareness and hazard perception tests was designed to be categorized into 5 grades, classifying the best as grade 1 and the worst as grade 5. As the result, low grades on situation awareness test had positive relationship with accumulated penalty points, frequency of accidents and safety index. Grades on hazard perception test were also positively correlated with accident frequency and safety indices. This suggests situation awareness ability of commercial drivers is significantly related to traffic violations and accident causing tendencies.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3383-3388
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• 2007

To compare the sensor performance of AE leak diagnosis system which can measure valve leak conditions, AE activities such as RMS voltage level, AE signal trend, leak rate degree according to AE database, FFT spectrum were measured on valve of the simulated test system for power plant. AE activities were recorded and analyzed from various operating conditions including different temperature, pressure difference, valve size and fluid using both piezoelectric acoustic emission sensor and Pb-Free acoustic emission sensor. The results of this study are utilized to select the type of sensors, the frequency band for filtering and thereby to improve the signal-to-noise ratio for diagnosis or monitoring of valves in operation. As the final result of application study above, portable type leak diagnosis system by AE was developed. The outcome of the study can be definitely applied as a means of the diagnosis or monitoring system for energy saving and prevention of accident for power plant valve.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6D
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• pp.775-789
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• 2008

The Office for Government Policy Coordination announced in 2006, september that a scheme of pre-signal would show remarkable outcome to reduce traffic accidents. Therefore, the Ministry recommended applying preferentially the pre-signal scheme to enhancement projects for high accident frequency areas. In case that the suggested pre-signal was unilaterally introduced to the enhancement projects at intersections, it might rather cause a big trial and error in terms of traffic safety. Hence, on the basis of quantitative analysis, this study was to indicate a pre-signal's effectiveness to reduce the traffic accidents, to illustrate a trend of the accident type due to the pre-signal, and to introduce intersection type that could be appropriate for the pre-signal. The methodology adopted Comparison-Group Method which was developed by Hauer. Through this methodology, overall effectiveness to reduce the accidents is considered positive but individual effectiveness by intersection and by accident case was different. All cases of the accidents at small scale intersection demonstrated positive results to reduce its accidents, while in case of frontal collision and side-right angle collision out of the accident types, the installation of pre-signal rather caused a negative result increasing the accident in terms of the traffic safety. I hope that this study would be a useful reference for future development of the estimation of accident effectiveness. Thus, when the pre-signal is being installed in the big intersection, it is recommended operating the installation concerning carefully improvements about muliple aspects as traffic operation, traffic facility, human factor etc.

• Journal of Pharmacopuncture
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• v.23 no.4
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• pp.201-211
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• 2020

Objectives: The purpose of this study is to comprehensively review Korean domestic studies and investigate the research trends of pharmacopuncture therapy on cervical pain caused by traffic accidents. Methods: Domestic studies between February 1999 and May 2020 from four Korean databases were searched with combinations of keywords 'cervical pain', 'traffic accident', 'whiplash injury', and 'pharmacopuncture'. Results: 17 studies were selected for review, including 7 randomized controlled trials, 5 retrospective observational studies, 3 case reports, and 2 non-randomized controlled trials. Each study was reviewed by published year, study type, types of pharmacopuncture solutions, selected acupuncture points, dosage of pharmacopuncture solutions, frequency of treatment, concurrent treatments, outcome measurements, and the effectiveness of pharmacopuncture therapy. The results are as follows: (1) It showed that the total number of published studies had increased slightly in the last 10 years compared to the previous decade. (2) The pharmacopuncture solutions used in the studies were in the following order: Bee-Venom (蜂毒), Jungsongouhyul (中性瘀血), Hwangryunhaedoktang (黃連解毒湯) and Soyeom (消炎). Frequently used acupuncture points were GB20, GV21, A-shi point, GV16, EX-B2, and SI15 in order. (3) The most commonly used total injection dosage was 1.0 cc at a time, and the frequency of treatment was twice a week. (4) Concurrent treatments such as acupuncture, herbal medication, physical therapy and Chuna manual therapy were performed in all 17 studies. (5) Pharmacopuncture therapy showed positive effects on cervical pain caused by traffic accidents in all 17 studies reviewed. Conclusion: Pharmacopuncture therapy was effective in cervical pain caused by traffic accidents in all 17 studies selected. Further studies will be needed using more larger scales and more objective data to confirm the effectiveness of pharmacopuncture therapy and to generalize its application.

• Journal of Preventive Medicine and Public Health
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• v.27 no.3 s.47
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• pp.447-463
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• 1994

Despite the public health importance of injury and poisoning in terms of its high mortality and incidence, epidemiologic information to be utilized are scarce in Korea. This study was carried out in 1990 on a representative sample population (about 55,000 persons) along with the 6th National Tuberculosis Prevalence Survey in order to estimate the magnitude of injury and poisoning occurrence and to identify its epidemiologic characteristics which can be aided for establishing preventive strategy. Pre-tested and structured Questionnaire was used by trained interviewer to collect data including general information of the person, various information on the injury and poisoning during the past one year such as time and place of its occurrence, its nature and external causes, type of medical institute attended, duration of treatment and outcome of the accident occured. In analysis of the data collected incidence rates per 1000 persons by sex, age group and its nature as well as external causes, and relative frequencies were calculated. The result obtained are as followings; 1. The incidence rate per 1000 was 30 for both sexes, 39 for male and 22 for female, male being 1.8 times more frequent than female. Age adjusted incidences were not much different from the crude rates. Age group specific rate curve showed bimodal shape in both sexes, small peaks in preschool children and higher peaks in older ages. The incidence rate per 1000 people by area was highest in Jeon-bug province (57/1000) and the lowest in Daegu city(11/1000). 2. The place where the injuries occured were road in 46%, within the boundary of house in 25%, and working place in 12% The injuries and poisoning had occured more frequently during the months from March to August of the year than other months. 3. The relatively frequent injuries by its nature were contusion with intact skin surface (19%), fracture of upper limb (13%), open wound of head, neck and trunk (12%) and fracture of lower limb (11%) among males; contusion with intact skin surface (28%), sprains and strains of joints and adjacent muscle (14%), fracture of upper limb (10%) and fracture of lower limb (9%) among females. Higher incidence rate among males than females were fracture of skull (4.5 times), open wound and fractures of limbs ($2{\sim}3$ times). Age specific rate of injuries and poisoning by its nature showed increasing pattern by age in fractures of upper and lower limbs and sprains & strains of joints whereas the age group of 30's showed highest incidence in open wounds of upper limb. Fractures of radius and ulna in upper limb, fractures of tibia & fibula and ankle in lower limb were most frequent among fractures of upper and lower limbs. The frequent injuries among sprains and strains of joints and adjacent muscles were that of ankle, foot and back, and among open wound were that of head and fingers. 4. Relative frequency of injuries and poisoning by external causes showed following order : other accidents (25%), accidental falls (23%), motor vehicle accident (22%) and other road vehicle accident (14%) among males and accidental falls (37%), motor vehicle accident (24%) and other accident (18%) among females. The external causes revealing higher incidences among males than females, were other road vehicle accident (4.8 times), vehicle accident not elsewhere classifiable (4.4 times), accidental poisoning (4.4 times), accidents due to natural and environmental factors (2.8 times), and sucide & self-inflicted injuries (2.8 times). Age specific incidence by external causes for frequent injuries showed that incidence of other accident steadily increased from 10's till age 50's; motor vehicle traffic accident increased from age 20's and dropped after age 60's; on the other hand accidental fall increased strikingly by age. The most frequent external causes among motor vehicle traffic accidents was motor vehicle traffic accident involving collision with pedstrain (69%), pedal cycle accident (30%) and other road vehicle accident (71%) among other road vehicle accidents; falls on same level from slipping, tripping or standing (44%) and other falls from one level to another among accidental falls; accidents caused by machinary (32%) for male and striking against or struck accidentally by objects or person for female among other accidents. 5. Seventy nine percent of the injuries and poisonings were treated in general hospital or hospital/clinic. The duration of treatment ranged from a few days to 123 weeks; the majority(52%) took under 2 weeks, 36% for $3{\sim}8$ weeks and 4% over 21 weeks. 6. The accident resulted in full recovery of normal healthy state in 62%, residual functional defects in 21% and on process of treatment in 16%.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.425-430
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• 2008

To verify the system performance of portable AE leak diagnosis system which can measure with moving conditions, AE activities such as RMS voltage level, AE signal trend, leak rate degree according to AE database, FFT spectrum were measured during operation on total 11 valves of the secondary system in nuclear power plant. AE activities were recorded and analyzed from various operating conditions including different temperature, type of valve, pressure difference, valve size and fluid. The results of this field study are utilized to select the type of sensors, the frequency band for filtering and thereby to improve the signal-to-noise ratio for diagnosis for diagnosis or monitoring of valves in operation. As the final result of application study above, portable type leak diagnosis system by AE was developed. The outcome of the study can be definitely applied as a means of the diagnosis or monitoring system for energy saving and prevention of accident for power plant valve. The purpose of this study is to verify availability of the acoustic emission in-situ monitoring method to the internal leak and operating conditions of the major valves at nuclear power plants. In this study, acoustic emission tests are performed when the pressurized temperature water and steam flowed through glove valve(main steam dump valve) and check valve(main steam outlet pump check valve) on the normal size of 12 and 18 ". The valve internal leak monitoring system for practical field was designed. The acoustic emission method was applied to the valves at the site, and the background noise was measured for the abnormal plant condition. To improve the reliability, a judgment of leak on the system was used various factors which are AE parameters, trend analysis, frequency analysis, voltage analysis and amplitude analysis of acoustic signal emitted from the valve operating condition internal leak.

• Journal of the Earthquake Engineering Society of Korea
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• v.25 no.2
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• pp.53-58
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• 2021

Nuclear power plant's safety against seismic events is evaluated as risk values by probabilistic seismic safety assessment. The risk values vary by the seismic failure correlation between the structures, systems, and components (SSCs). However, most probabilistic seismic safety assessments idealized the seismic failure correlation between the SSCs as entirely dependent or independent. Such a consideration results in an inaccurate assessment result not reflecting real physical phenomenon. A nuclear power plant's seismic risk should be calculated with the appropriate seismic failure correlation coefficient between the SSCs for a reasonable outcome. An accident scenario that has an enormous impact on a nuclear power plant's seismic risk was selected. Moreover, the probabilistic seismic response analyses of a nuclear power plant were performed to derive appropriate seismic failure correlations between SSCs. Based on the analysis results, the seismic failure correlation coefficient between SSCs was derived, and the seismic fragility curve and core damage frequency of the loss of essential power event were calculated. Results were compared with the seismic fragility and core damage frequency of assuming the seismic failure correlations between SSCs were independent and entirely dependent.

• The Journal of Korean Medicine
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• v.15 no.2 s.28
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• pp.28-39
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• 1994

Clinical studies were made on 79 cases with thalamic hemorrhage diagnosed by computed tomographic scan and only localized on the thalamic area, were admitted to the Kyung San University Taegu Oriental Medical Hospital from August 1990 to March 1994. The age and sex distribution, sites of hematoma, recurrence rate, incidence of hypertension, inducing factor, prodromal syndroms, symptoms and neurologic signs on admission, relationship between the hospital course and many factors affecting the prognosis such as age, side of hematoma, level of consciousness, volume of the hematoma. ventricular hemorrhage were analysed. The results were summarized as follows; 1. The most prevalent age group was above 60 years of age with 50-59 years, 70-79 years, 40-49 years and 80-89 years of age in the order of frequency. Male to female ratio was 1:1.55. 2. The ratio of left hematoma to the right was 1.32:1. The recurrence rate of cerebrovascular accident was 17.7% 3. The incidence of hypertension was 69.6% and inducing factors of thalamic hemorrhage in the order of frequency were physical work(29.1%), drinking or eating(13.9%), walking(12.7%) and rest(12.7%), The prodromal syndroms were numbness of extremities(5.1%), headache(2.5%), fatigue(2.5%), dizziness(1.3%), insomnia(1.3%), but prodromal syndrom was not found in 89.9% of thalamic hemorrhage. 4. The symptoms and neurologic signs on admission in the order of frequency were motor disturbance(98.7%), dysarthria(82.3%), positive Babinski sign(78.5%), headache(69.6%), dizziness(62.0%). hemisensory deficit(48.1%). nausea or vomiting(39.2%), absent or sluggish light reflex(35.4%), changes of consciousness (35.4%), dysphagia (20.3%), voiding difficulty.(13.9%), facial palsy(6.3%), aphasia(3.8%), seizure(38%), 6th N. palsy(3.8%) and small pupil(1.3%). 5. The rate of improvement was found almost equally in the 4th, 5th and 6th decades, but it was shown with dramatic decrease in the over 7th decades. The hospital course had no relationship with the side of hematoma but the level of consciousness had influence upon the prognosis. 6, The small hematoma had better outcome than large in the volume of hematoma under 15cc, but volume of the hematoma had no influence upon the prognosis because the rate of improvement was 75.0% in the volume of hematoma over 15cc. The hospital course had no relationship with ventricular hemorrhage.