• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.32.6-32
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• 2002

The damage localization of the structural system using the natural frequency measurement only is proposed. The existing methods use the changes of mode shape, strain mode shape or curvature mode shape before and after the damage occurrence as these shapes carry the geometric information of the structure. Basically, the change of natural frequencies of the structure can be used as the indicator of the damage occurrence but not as the indicator of the damage location as the natural frequency changes does not carry the geometric information of the structure. In this research, the feedback scope method that measures the natural frequency changes of the structure with and without the feedback Ioo...

• 한국기후변화학회지
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• 제9권4호
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• pp.461-470
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• 2018

The frequency of extreme weather events was analyzed using meteorological data (air temperature, precipitation, and duration of sunshine) collected from 61 stations over a 36-year span (1981-2016). The 10-day meteorological data were used as a basic unit for this analysis. On average, the frequency of occurrence of abnormal weather was 9.88 per year and has increased significantly during this 36-year period. According to the type of abnormal weather, the frequencies of occurrence of abnormally high air temperature and short duration of sunshine have increased by 0.50 and 0.41 per 10 years, respectively; however, that for abnormally low air temperature has decreased by 0.31 per 10 years and the trend was statistically significant. The highest frequency of abnormal weather appeared in 2007, with a frequency of 14.31. Abnormal weather was the most frequent at Yeongdeok station with an average frequency of 11.78 per year over this 36-year span.

• Journal of Forest and Environmental Science
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• 제32권2호
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• pp.149-157
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• 2016

Understanding regional characteristics in forest fire occurrence is important to establish effective forest fire prevention policy in Korea. This study analyzed the characteristics of forest fires occurred in 16 administrative districts for recent 25 years (1990~2014) to examine regional characteristics in forest fire occurrence. Forest fire occurrence reflects regional characteristics depending on climatic factors as well as region's society-cultural factors. Results showed that the first cause of forest fire occurrence was carelessness by human activities throughout all administrative districts, however, the second cause depends on regional characteristics. As the results of forest fire occurrence period analyzed for 10 days, the most forest fires occurred in the southern region during January to March, while forest fires in the northern region occurred mostly during March to April. We classified forest fire occurrence patterns into three types (centralized: Gyeonggi-do, dispersal: Busan, horizontally distributed: Gyeongsangnam-do) by multi-temporal analysis for forest fire occurrence period.

• 한국군사과학기술학회지
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• 제23권6호
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• pp.582-590
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• 2020

This paper presents the results of new error analysis on the veering of marine target with the concept of frequency of occurrence, and shows how to apply the midcourse guidance errors of anti-ship missile. The veering error would be a dominant factor in the midcourse guidance errors with flight time increase. This study suggests the reasonable application method of the veering error based on the characteristics of abnormal error, and describes the tailoring method including trade-off between the midcourse guidance range of veering target and the value of frequency of occurrence on veering error.

• 한국대기환경학회지
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• 제5권1호
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• pp.88-95
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• 1989

The aspects of the occurence frequency of $SO_2$ concentration were studied with the observed data in Seoul and the scheme that is capable of estimating not only highest concentration for a variety of averaging times but also concentrations for arbitary occurrence frequency with long term arithmatic mean and geometric standard deviation data, was evaluated. The results of the statistical analysis show that the occurrence frequency is almost log normal except a few cases, and 3rd highest values of daily mean concentration were about 4.2 $\sim$ 5.2 times higher than annual arithmatic mean. The evaluation with the observed hourly concentration shows that the scheme fairly well estimate the short concentration of arbitary occurrence frequence and it can be used for air quality management and environmental impact assessment.

• 한국기후변화학회지
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• 제4권2호
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• pp.189-199
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• 2013

기상청 소속 60개 지점에서 관측한 1973년부터 2010년까지의 순별 평균기온을 조사기간의 평균값과 비교하는 평균편차법으로 이상고온과 이상저온의 출현횟수를 조사하고, 시 공간별로 분석하였다. 과거 38년간 이상기온의 출현횟수는 연 평균 1.8회(이상고온 0.65회, 이상저온 1.15회)로 조사되었다. 연도별로는 1998년에 이상고온의 출현횟수가 2.47회로 가장 많았고, 이상저온의 출현횟수는 1980년에 5.07회로 가장 많았다. 연대별 이상고온의 연간 출현횟수는 1980년대(1981~1990년)의 0.2회에서 2000년대(2001~2010년)의 1.0회로 5배 이상 크게 증가한 반면에, 이상저온의 연간 출현횟수는 1970년대(1973~1980년)의 2.06회에서 2000년대의 0.63회로 크게 감소하는 경향을 나타내서, 최근 우리나라에서의 온난화 현상을 나타내고 있었다. 농업기후지대로 구분하여 분석하면, 과거 38년간 이상고온의 출현횟수가 가장 많았던 농업기후지대는 태백고냉지대(대관령, 평창 등)로서 연평균 0.76회이었고, 동해안 북부지대(강릉, 속초 등)는 0.74회로 다음으로 많았다. 반면에, 이상고온의 출현횟수가 가장 적었던 농업기후지대는 동해안 남부지대(포항, 울산 등)로 0.45회였다. 과거 38년간 이상저온의 출현횟수가 가장 많았던 농업기후지대는 소백서부 내륙지대(청주, 대전 등)로 연평균 1.43회이었고, 이상저온의 출현횟수가 가장 적었던 농업기후지대는 동해안 중부지대(울진, 영덕 등)로 연 평균 0.64회이었다.

• 한국환경과학회지
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• 제3권1호
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• pp.1-9
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• 1994

We have Studied the characteristics of wind over Pusan coastal area in order to precisely predict surface wind having an important effect on oil spill fate using the data on surface observation of Pusan, Kimhae and Gadeogdo island which are collected during the 3 years from 1988 to 1990. We also investigated the correlation of the surface wind between Pusan, Kimhae and Gadeogdo island. In both Pusan areas and Kimhae, the land and sea breeze occurs during. the whole season except for winter. The occurrence frequency of land and sea breeze is significantly high from April to August. The correlation of surface wind between Pusan, Kimhae and Gadeogdo island surface wind is high in the daytime. The occurrence frequency of sea breeze in the Kimhae areas is higher than that in Pusan on the basis of the present criteria. For monthly occurrence, Pusan has the highest occurrence frequency of the sea breeze in August and Kimhae has in May.

• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1993년도 추계학술대회논문집
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• pp.124-132
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• 1993

This study compared two prediction methods-regression and artificial neural network (ANN) on the visual search performance when monitoring a multi-parameter screen with different occurrence frequencies. Under the highlighting condition for the highest occurrence frequency parameter as a search cue, it was found from the requression analysis that variations of mean search time (MST) could be expained almost by three factors such as the number of parameters, the target occurrence frequency of a highlighted parameter, and the highlighted parameter size. In this study, prediction performance of ANN was evaluated as an alternative to regression method. Backpropagation method which was commonly used as a pattern associator was employed to learn a search behavior of subjects. For the case of increased number of parameters and incresed target occurrence frequency of a highlighted parameter, ANN predicted MST's moreaccurately than the regression method (p<0.000). Only the MST's predicted by ANN did not statistically differ from the true MST's. For the case of increased highlighted parameter size. both methods failed to predict MST's accurately, but the differences from the true MST were smaller when predicted by ANN than by regression model (p=0.0005). This study shows that ANN is a good predictor of a visual search performance and can substitute the regression method under certain circumstances.

• 한국지역지리학회지
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• 제12권4호
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• pp.461-474
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• 2006

우리나라의 여름과 겨울철의 이상기온 출현 분포 특성을 분석한 후 여름과 겨울철의 월별 이상기온 출현 빈도에 의하여 한반도 이상기온 지역을 5개로 구분하였다. 여름철 이상고온의 출현 빈도가 다른 이상기온 지역보다 2배 이상 높은 제 I지역(중부 동안), 겨울철 이상고온 출현은 낮고 이상저온 출현은 높은 제 II지역(경기 서안과 중부 내륙 북부), 다른 지역과 달리 여름과 겨울철 이상기온의 출현이 특정 계절에 집중되지 않는 제 III지역(중 남부의 서부), 여름철 이상고온의 출현 빈도가 가장 낮고 겨울철 이상고온의 출현도 비교적 적은 제 IV지역(산지와 남부 및 남해안 동부), 겨울철 이상고온 빈도가 가장 높은 제 V지역(소백산맥/노령산맥 이남과 남해안 서부 및 제주도)이다.

• Journal of Information Technology Applications and Management
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• 제15권2호
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• pp.67-82
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• 2008

Risk that breed large size disaster is happening variously for cause at social. natural a management. Incidence and damage scale are trend that increase rapidly than past. In these circumstance, to keep operational continuity of organization, area, society, risk management action that establish systematic counter measure estimating and analyze occurrence possibility and expectation damage of risk is essential indispensable issue and the best countermeasure. Risk management action does by main purpose establish optimum disaster reduction countermeasure. To deduce various countermeasure, process that estimate and analyze occurrence possibility and expectation damage of risk is essential indispensable issue. Therefore, this paper studies process design that can presume risk occurrence frequency and damage scale through distribution of probability.