• Journal of Environmental Science International
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• v.2 no.3
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• pp.235-243
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• 1993

Extreme environments and freak wave characteristics in the coastal waters of Korean Peninsula are analyzed using the observed wave data. Freak wave has been intensely emphasized as an important environmental force parameter in several recent research works. However, the mechanism and occurrence probability of freak wave are not clarified. The aims of this study we: to summarize the distribution of extreme environment for wind waves, and to find occurrence probability of freak wave in the coastal waters of Korean Peninsula. These extreme sea conditions are discussed by applying extreme value analysis method, and the statistic characteristics are summarized which can be used to the design and analysis of coastal structures. The mechanism and the occurrence probability of freak wave are also discussed in detail using wave parameters in considered with wave deformation in the coastal waters. Key Words : extreme wave, freak wave, extreme analysis, design wave, probability density.

• Proceedings of the Korean Society for Quality Management Conference
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• 2010.04a
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• pp.16-23
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• 2010

This research analyzed about inconsistence and cause of the audit result on national defense quality management system in certification company. Direction of research analyzes corelation with distribution by items at national defense quality management system standard by Investigated number and occurrence of examination report slight and critical incongruity on 2008 and 2009. Study finding slight and critical incongruity happened to first examination average 10.2 items, renewal examination average 7.0 items. By incongruity occurrence appeared high in item that there are a lot of examination item shares of standard requirement, it was studied by correlative thing between the examination with standard. Factor of incongruity occurrence was proved to comprehension insufficiency for quality management system, quality procedure insufficiency, didn't fulfil proceedings, business was unripe. In this papers, we contribute to propose direction for improvement of national defense quality management system comprehensive faculty elevation and national defense quality certification in this treatise.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.39 no.5
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• pp.32-38
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• 2007

The purpose of this study is to investigate the cause of fine wrinkles occurred in silky wallpaper and its solution. The characteristics of base papers, wallpapers and adhesives (conventional and modified) were evaluated to find the possibility for the occurrence of fine wrinkles. It was found that the base papers and wallpapers did not cause the occurrence of silky wallpaper. It was concluded that the fine wrinkles in silky wallpaper was caused by the nonuniform distribution of adhesive, the localized shrinkage of adhesive and the breaking the balance between the resistance of wallpaper and shrinkage of adhesive. Three possible solutions for the prevention of the occurrence of fine wrinkles in silky paper were recommended.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.28B no.9
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• pp.692-703
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• 1991

A Korean word is composed of syllables. A Korean syllable is regarded as a random variable according to its probabilistic property in occurrence. A Korean syllable is divided into 'choseong', 'jungseong', and 'jongseong' which are regarded as random variables. We can consider teh conditional probatility of syllable as an index which represents the occurrence correlation between syllables in Korean words. Since the number of syllables is enormous, we use the conditional probability of a' choseong', a 'jungseong', and a 'jongseong' between syllables as an index which represents the occurrence correlation between syllables in Korean words. The length distribution of Korean woeds is computed according to frequency and to kind. Form the cumulative frequency of a Korean syllable computed from multi-syllable Korean woeds, all probabilities and conditiona probabilities are computed for the three random variables. The conditional probabilities of 'choseong'- 'choseong', 'jungseong'- 'jungseong', 'jongseong'-'jongseong', 'jongseong'-'choseong' between adjacent syllables in multi-syllable Korean woeds are computed.

• Atmosphere
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• v.20 no.1
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• pp.27-35
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• 2010

This study analyzes the climate change in Korea and its impact on the occurrence of forest fire events. The forest fire occurrences in Korea tend to concentrate around large cities. In addition, the spatial distribution of the forest fire occurrence seems to agree with local climate conditions. Though the occurrence of the forest fire shows strong interannual variation, it also exhibits a positive trend. Because the forest fire frequently occurs during early spring, we examined long term climate variability in Korea for the early spring seasons. The climate change in Korea generally has brought warmer, drier, and less precipitable conditions during the early spring. The changes of the atmospheric conditions provide favorable condition for the forest fire. The climate changes in Korea also depict distinct spatial variability according to the atmospheric variables. We compared the regional trend of the fire occurrence with the climate trends. The results show the sharpest growing in the forest fire occurrence over southwest of Korea. This study suggests that the decrease in the precipitation day might affect the sharp increasement of the forest fire occurrence in the southwest of Korea.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.21 no.4
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• pp.119-125
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• 2013

Since year 2001 to the present time, the aircraft accidents and serious incidents in our country have surpassed 150 occurrences. The Boeing has published the statistical summary of commercial jet airplane accidents annually for the past 10 years on the basis of the occurrence categories defined by the CICTT(CAST/ICAO Common Taxonomy Team), and the number of occurrences is in order of loss of control(LOC-I), controlled flight into terrain(CFIT) and runway excursion (RE). Like the NTSB and the EASA, when fatal and non-fatal accidents are aggregated, though fatality rate is low, abnormal runway contact(ARC), system/component failure(SCF-PP/NP), ground handling(RAMP) rank high in the CICTT occurrence categories. With the less occurrence frequency, it is difficult to statistically analyze the aircraft accidents in our country, thus customarily the accidents and the serious incidents on aggregate are consolidated, and the statistical analysis is performed. This study categorizes the accidents and serious incidents to the domestic transportation aircraft in the past 10 years according to the CICTT occurrence categories, that is compared with foreign practices, and the implications have been discussed. From years 2001 through 2010, the accidents to the domestic transportation aircraft occurred in order of system failure(SCF-NP), ARC and power plant failure(SCF-PP), and when the accidents and the serious incidents are consolidated and analyzed, it is verified that a distribution appears similar to the European accident occurrence categories defined from 300 accident occurrence data.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.2
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• pp.151-156
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• 2019

The aim of this investigation is to detect specific waveforms in a distribution line prior to the occurrence of a fault. Conditions were introduced such that a feeder remote terminal unit (FRTU) of the distribution automation system selects and stores fault waveforms from the different waveforms detected in the distribution line. In addition, an algorithm was developed to detect specific waveforms from the fault waveforms stored using the FRTU. This algorithm exploits the duration and periodicity of harmonic changes in voltage and current. The efficacy of the algorithm was confirmed based on the measurements of fault waveforms in an actual distribution line. The results indicated that faults in a distribution line can be predicted via experimental measurements.

• The Journal of Korean Physical Therapy
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• v.2 no.1
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• pp.21-33
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• 1990

The purpose of this study is to investigated the occurrence properties of the cerebrovascular accidents. Clinical observations were done 252 cases, were carried from June, 1989 to May, 1990 at 4 general hospital in Taegu, Korea. The following results have been obtained ; 1. Among the 252 cases of cerebrovascular accidents, males was noted in $51.6\%$ and females in $48.4\%$. The ratio between males and females was 1.1 : 1 in whole groups of cerebrovascular accidents, and in aging distribution, it was showed variety distribution in age groups, fifties, sixties and forties were in order of frequency, particulary, more than half was shelved from 50 to 69. 2. Among the 252 cases of cerebrovascular accidents, cerebral hemorrhage was rioted in $64.3\%$, cerebral infarction in $25.8\%$, cerebral thrombosis in $6.3\%$, subarachnoid hemorrhage in $2.4\%$ and cerebral embolism in $1.2\%$. 3. In distribution of academic career, high school level was noted in $37.7\%$, elementary school level in $30.5\%$, middle school level in $17.1\%$, elementary school level in $30.5\%$, middle school level in $17.1\%$ arid college level in $14.7\%$. 4. In distribution of occupation, office worker was noted in $21.8\%$, housewife in $20.2\%$, the others in $19.1\%$, physical laborer in $18.3\%$ and inoccupation in $18.3\%$. 5. In seasonal distribution, spring was noted in $34.9\%$, winter in $32.5\%$, autumn in $20.3\%$ and summer in $12.3\%$. 6. Among the preceding diseases at the onset of cerebrovascular accidents, hypertension was noted in $51.6\%$, no preceding disease in $20.2\%$, other disease in $10.3\%$ and diabetes mellitus in $9.5\%$ and cardiovalvular disease in $6.0\%$. 7. In systolic blood pressure on admission, 160-199mmHg was noted in $32.2\%$, 200-239mmHg in $23.4\%$, 140-159mmHg in $19.4\%$, below 140mmHg in $16.3\%$, and above 240mmHg in $8.7\%$, While, in diastolic blood pressure, above 130mmHg noted in $24.6\%$, below 90 mmHg in $17.1\%$, 120-129mmHg in $13.1\%$ and was 90-99mmHg in $11.1\%$. 8. In major predisposing factors of patients, emotional stress was noted in $20.2\%$, physical action in $17.9\%$, rest in $16.9\%$, while sleeping in $10.7\%$, drinking in $9.9\%$ and defecation in $7.9\%$. 9. In distribution of affected side, left was noted in $48.4\%$, right in 42.1 and both $9.5\%$. 10. In rates of recurrent cases, first attach was noted in $79.0\%$, 1st recurrence in $17.0\%$, 2nd recurrence in $3.6\%$ and 3rd recurrence in $0.4\%$.

• Journal of Information Technology Services
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• v.18 no.1
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• pp.131-140
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• 2019

This study compares and analyzes the spatial distribution of people in two cities using location information in twitter data. The target cities were selected as Paris, a traditional tourist city, and Dubai, a tourist city that has recently attracted attention. The data was collected over 123 days in 2016 and 125 days in 2018. We compared the spatial distribution of two cities according to the two periods and residence status. In this study, we have found a hot place using a spatial statistical model called dart-shaped space division and estimated the urban area by reflecting the distribution of tweet population. And we visualized it as a CDF (cumulative distribution function) curve so that the distance between all the tweets' occurrence points and the city center point can be compared for different cities.

• Korean Journal of Agricultural Science
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• v.41 no.4
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• pp.303-308
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• 2014

This study was conducted in order to utilize the basic data for weed control by surveying the occurrence of weed species. Total 63 sites of upland Chinese cabbage fields in Chungnam Provinces were investigated. The result of survey, 71 weed species in 25 families were identified and classified to 39 annuals, 16 biennials and 16 perennials. Based on the occurrence ratio, the most weed species belonged to Compositae (20 species). 8, 6 and 5 weed species belonged to Poaceae, Cruciferae and Polygonaceae, respectively, and these 10 weed species in the most six families accounted for 50% of total weed occurrence. The most dominant weed species in upland Chinese cabbage fields were Portulaca oleracea (8.07%), followed by Digitaria ciliaris (7.54%), Rorippa palustris (6.44%), Chenopodium album (5.73%), Echinochloa crus-galli (5.02%) and Cyperus amuricus (3.95).