• Communications of Mathematical Education
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• v.18 no.1 s.18
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• pp.89-98
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• 2004

한국과 미국(North Carolina주)의 확률과 통계 교육 내용을 고찰한 결과 한국과 미국(North Carolina주)은 내용적인 면에서 많은 차이를 보였다. 한국의 경우, 9-가 단계와 10-가 단계, 선택과목 중 수학 I, 실용수학, 이산수학 과목에 제시되어 있는 확률과 통계 영역은 심화선택과목인 확률과 통계 과목의 내용을 축소하여 재구성한 내용을 제시하고 있다. 미국(North Carolina주)은 한국과는 달리, Introductory Mathematics, Algebra(I, II), Technical Mathematics(1, 2) Advanced Mathematics, Advanced Placement Calculus, Discrete Mathematics, Integrated Mathematics(1, 2, 3), Geometry 과목에서 확률과 통계 영역은 각 과목과 연관성 있는 내용으로 구성되어 있다. 한국의 심화 선택과목인 확률과 통계 과목과 미국(North Carolina주)의 AP통계(Advanced Placement Statistics)를 비교한 결과, 전체적으로, 자료의 정리, 확률변수와 확률분포 영역에서 한국과 미국(North Carolina주)은 거의 유사성을 보이고 있지만, 통계적 추론에서는 미국(North Carolina주)이 한국에 비하여 강화되어 있음을 알 수 있다.

• Journal of the Korean Data and Information Science Society
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• v.26 no.2
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• pp.313-322
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• 2015

A mixture distribution of a discrete uniform or degenerated distribution and two binomial distribution is proposed and a method of obtaining the maximum likelihood estimates of the parameters is provided. For the proposed model simulation studies were conducted to see performance of the maximum likelihood estimates and a mixture of a degenerated distribution and two binomial distributions was applied to fit a lecture evaluation data to show a good result.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2002.11a
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• pp.367-368
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• 2002

부산광역시 해운대 신시가지 소재의 생활폐기물 소각장 운전에 따른 사후환경영향조사의 일환으로, 소각장 주변 반경 2km이내의 영향 예상지역에 대한 대기질 조사로서 ⅰ) 아황산가스, 일산화탄소, 이산화질소, 오존, 분진, 납 등의 대기환경기준항목 7가지, 알루미늄, 카드늄, 크롬 둥의 중금속류 8개 항목, 벤젠, 톨루엔 둥의 휘발성유기화합물질 4개 항목에 대한 측정 및 분석을 실시하고, ⅱ) 종합처리장 주변의 대기질 실측조사를 통하여 나타난 자료를 바탕으로 향후 대기질에 의한 주변 환경상의 영향을 종합 분석하여 그 개선방안을 수립하고자 한다. (중략)

• Annual Conference of KIPS
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• 2009.11a
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• pp.425-426
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• 2009

본 논문은 차량형 네트워크에서 고급화된 루트 조회 요청의 응답시간을 측정하는 시뮬레이터를 구현하고 그 측정된 결과를 도시한다. 이산 이벤트 시뮬레이터에 기반하여 서버의 주기적 업데이트, 게이트웨이에서의 레코드당 리프레쉬, 차량으로부터의 조회 요청 발생 등의 사건들을 정의하고 이에 대한 동작을 구현한다. 시간 지역성을 대표하는 LRU 방식과 공간 지역성을 대표하는 FAR 방식의 성능을 측정하기 위해 참조시간을 기록하는 자료구조와 경위도 좌표를 거리로 변환하는 모듈을 작성하였으며 기존의 위치 이력 데이터로부터 조회 요청을 생성한다. 응답시간을 측정한 결과는 공간 지역성이 시간 지역성보다 응답시간에 더 많은 영향을 미치는 것으로 나타났으며 낮은 프리페치 부하에서 최대 4배 가량의 응답시간 차이를 보인다.

• Survey Research
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• v.11 no.2
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• pp.97-121
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• 2010

Using the 1998-2004 Health and Retirement Study(HRS), this study explored the determinants of private long-term care insurance(LTCI) ownership and the first home care use. To account for the interaction between LTCI purchase and home care use, this study used two-period utility model as theoretical framework. Discrete time model was used as an empirical model to incorporate the time-dependent feature of LTCI ownership. And this study accounted for the endogeneity of LTCI ownership and home care use by employing full information maximum likelihood estimation. This study indicated insignificant effects of private LTCI ownership and Medicaid eligibility on the home care use. Also, the effects of income and assets on home care utilization were negligible. Those who have poor health condition and who do not have potential informal caregivers were more likely to use home care. For private LTCI ownership, income and assets have positive relationship with LTCI purchase, and poor health status and age were negatively related to LTCI purchase. The elderly living with children and those who have more siblings were less likely to have private LTCI, and those who lived with spouses with no children were more likely to buy private LTCI. Based on the findings, this study provides implications to design long-term care(LTC) policies in the U.S. and to develop LTC planning education programs.

• The Journal of the Petrological Society of Korea
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• v.25 no.2
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• pp.143-149
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• 2016

Eruptive volumes of three monogenetic volcanoes (Songaksan tuff ring, Biyangdo scoria cone, and Ilchulbong tuff cone) with the youngest eruption age are calculated using the model, applied to Auckland Volcanic Field in New Zealand, to investigate the volcanic eruption scale and to evaluate volcanic hazard of Jeju Island. Calculated eruptive volumes of the volcanoes are $24,987,557m^3$, $9,652,025m^3$, and $11,911,534m^3$, respectively, and the volumes include crater infill, tuff ring (tuff cone), scoria cone, and lava flow. Volcanic explosivity indices of Songaksan tuff ring, Biyangdo scoria cone, and Ilchulbong tuff cone are estimated based on the eruptive volumes to be 3, 2, and 3 respectively, and eruption type is Strombolian to Surtseyan. It is assumed that the amount of emitted sulfur dioxide gas is $2-8{\times}10^3kt/y$ according to the correlation between volcanic explosivity index and volcanic sulfur dioxide index. Recent age dating researches reveal evidences of several volcanic activities during the last 10,000 years indicating the possible volcanic eruption in Jeju Island in the near future. Therefore, it is necessary for appropriate researches regarding volcanic eruption of the island to be accomplished. In addition, establishment of the evaluation and preparation system for volcanic hazard based on the researches is required.

• Journal of Food Hygiene and Safety
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• v.32 no.6
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• pp.477-484
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• 2017

This study was conducted to investigate the content of sulfur dioxide, carotenoids and the degree of contamination of Bacillus cereus in 33 kinds of dried sweet potato from domestic mainly dried agricultural products in Korea. According to the characteristics of dried sweet potato samples, it was classified into four clusters and as a result of analyzing the contents of sulfur dioxide, carotenoids and the degree of contamination B. cereus was no significant difference among the clusters. The detection ranges of residual sulfur dioxide from 33 dried sweet potatoes ranged from 0.38 to 28.16 mg/kg, three cases (9.09%) were detected at the reference level of 10 mg/kg or more. But no samples exceeding 30 mg/kg, the tolerance level of sulfur dioxide in dried sweet potatoes were detected. Since dried sweet potato does not have a standard for carotenoids, when comparing the national and international standards of carotenoids, the range of detection of carotenoids in dried sweet potato was $46{\sim}2,663{\mu}g$/100 g, which was within the reference range of $0{\sim}9,826{\mu}g$/100 g. In principle colonies suspected to be B. cereus in dried sweet potato were not detected. In 7 cases (21.21%), there were detected in the range of 0.05~1.59 log CFU/g but not more than 3 log CFU/g as the reference value. The results of this study are expected to be used as basic data to establish quality standard for dried sweet potatoes. In order to control the quality of dried sweet potatoes in domestic market, raw materials, drying method and packaging after distribution, it is necessary to maintain and maintain the process steadily.

• Journal of the Korean Data and Information Science Society
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• v.28 no.3
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• pp.473-481
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• 2017

It is well known that the air quality of 92% of the world is known to exceed the standard of WTO and the death caused by air pollution is almost 6 million per year. The $PM_{2.5}$ concentration in Korea is the second most serious among the OECD countries following Turkey. Since the $PM_{2.5}$ has a direct effect on the respiratory system, it has been actively studied in domestic and foreign countries. But current research on the $PM_{2.5}$ is limited in weather factor or air pollutants. In this paper, we consider the influence of spatial neighbor with weather factor or air pollutants using spatial panel model. We applied the proposed method to 25 borough of Seoul in Korea. The result shows a significant effect of spatial neighbor on the $PM_{2.5}$ concentration fields.

• Korean Journal of Remote Sensing
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• v.34 no.6_3
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• pp.1383-1398
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• 2018

Sea surface wind is one of the most fundamental variables for understanding diverse marine phenomena. Although scatterometers have produced global wind field data since the early 1990's, the data has been used limitedly in oceanic applications due to it slow spatial resolution, especially at coastal regions. Synthetic Aperture Radar (SAR) is capable to produce high resolution wind field data. KOMPSAT-5 is the first Korean satellite equipped with X-band SAR instrument and is able to retrieve the sea surface wind. This study presents the validation results of sea surface wind derived from the KOMPSAT-5 backscattering coefficient data for the first time. We collected 18 KOMPSAT-5 ES mode data to produce a matchup database collocated with buoy stations. In order to calculate the accurate wind speed, we preprocessed the SAR data, including land masking, speckle noise reduction, and ship detection, and converted the in-situ wind to 10-m neutral wind as reference wind data using Liu-Katsaros-Businger (LKB) model. The sea surface winds based on XMOD2 show root-mean-square errors of about $2.41-2.74m\;s^{-1}$ depending on backscattering coefficient conversion equations. In-depth analyses on the wind speed errors derived from KOMPSAT-5 backscattering coefficient data reveal the existence of diverse potential error factors such as image quality related to range ambiguity, discrete and discontinuous distribution of incidence angle, change in marine atmospheric environment, impacts on atmospheric gravity waves, ocean wave spectrum, and internal wave.

• Journal of Korea Water Resources Association
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• v.34 no.2
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• pp.119-130
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• 2001

At-site and regional frequency analyses of annual maximum 1-, 2-, and 3-days rainfall in Han River basin was performed and compared based on the regional L-moments algorithm. To perform regional frequency analysis, Han River basin was subdivided into 3 sub-basins such as South Han River, North Han River, and downstream regions. For each sub-basin, the discordancy and homogeneity tests were performed. As the results of goodness of fit tests, lognormal model was selected as an appropriate probability distribution for both South Han River and downstream regions and gamma-3 model for North han River region. From Monte carlo simulation, RBIAS and RRMSE of the estimated quantiles from regional frequency analysis and at-site frequency analysis were calculated and compared each other. Regional frequency analysis shows less RRMSE of the estimated quantiles than at-sites frequency analysis in overall return periods. The differences of BRMSE between two approaches increase as the return period increases. As a result, it is shown that regional frequency analysis performs better than at-site analysis for annual maximum rainfall data in Han River basin.