• Journal of Korean Ophthalmic Optics Society
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• v.10 no.4
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• pp.305-312
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• 2005

In this thesis, Lohmann's algorithm and FFT (fast Fourier transform) are used to synthesize binary-phase holograms. FFT computing is carried out for the calculation of complex wavefronts of $128{\times}128$ sampling points of an object that is numerically specified. Then using the Lohmann's algorithm, the amplitude and the phase of complex wavefronts are encoded in binary holograms on each sampling points. PC (personal computer) and laser printer are used to plot binary-phase holograms and CGH (computer generated holograms) films are obtained from this plot by photographic reduction. Holographic images of numerically specified objects are reconstructed from the He-Ne laser and the inverse Fourier optics system. We estimate the quality of holographic images according to the sampling number, application of random phase, amplitude clipping and bleaching the CGH film. We derive optimized conditions to reconstruct better holographic images and to reduce the speckle noise. FFT and Lohmann's algorithm are implemented with MS Visual BASIC 6.0 for the programming of binary-phase hologram.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.5 no.2
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• pp.67-73
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• 1985

In Digital Terrain Model(DTM), more accurate data acquisition method is of importance. This paper has the purpose of accuracy analysis of progressive sampling method, one of data acquisition method. Especially, The following in accuracy analysis are compared and analyzed. -Comparison and analysis for position error between the digital contour lines using digital terrain model and the conventional contour lines using A-10 Plotter. -Analysis for height error of interpolation points according to application of progressive sampling method. For above numerical tests, Computer Program related to auto-carto of contour lines was made up. As a result of tests, threshold and sampling criterion have close of mutual relation to accuracy. Particularly, it was found that auto-carto of contour lines-threshold of 1.0 m and standard criterion-almost concurred in conventional contour lines.

• The Korean Journal of Applied Statistics
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• v.24 no.3
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• pp.477-484
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• 2011

When an event of target variable is rare, a widespread strategy is to build a model on the sample that disproportionally over-represents the events, that is over-sampled. Using the data over-sampled from the original data set, the predicted values would be biased; however, it can be easily corrected to represent the population. In this study, we investigate into the relationship between the proportion of rare event on a data-mart and the model performance using real world data of a Korean credit card company. Also, we use the methods for adjusting of posterior probability for over-sampled data of the offset method and the weighted method. Finally, we compare the performance of the methods using real data sets.

• The Korean Journal of Applied Statistics
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• v.23 no.5
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• pp.923-932
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• 2010

One of the problems in designing the fifth Korean National Health and Nutrition Examination Survey(KNHNES) is the lack of an appropriate sampling frame. Due to the significant time difference, we expect eight severe sampling frame errors if we use the sampling frame obtained from the latest population and housing census that was conducted in 2005. Thus, the construction of an appropriate sampling frame for the fifth KNHNES is crucial for a successful survey. We considered the construction of a sampling frame that overcomes the limitations of the 2005 population and housing census based frame. For the construction of eight new sampling frames, we considered the use of multiple sampling frames in which the frame for the apartment households and the frame for the general households are obtained from different sources.

• The Korean Journal of Mycology
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• v.37 no.1
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• pp.1-10
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• 2009

Total 222 lichen specimens of North Korea including 23 family, 54 genera and 119 species were newly obtained from the Hungarian Natural History Museum for the last 3 years. Among them, 12 species were added to Korean lichen checklist as new. All the species were deposited at the herbarium of Korea National Arboretum. In addition, unpublished list of lichen species distributed in Mt. Myohang was kindly donated from the Hungarian Natural History Museum. The list was originally prepared by North Korean lichenologists and kept in the museum from 1988. In the list, 26 family, 57 genera and 179 species of lichens were described and 17 species were included as new reports. This list provided 29 lichen species as new to the Korean Peninsula. This information will make significant contribution to lichenological study in the Korean Peninsula.

• 한국지구과학회:학술대회논문집
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• 2010.04a
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• pp.21-21
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• 2010

천연기념물 제395호 진주 가진리 새발자국과 공룡발자국 화석산지는 1997년 5월 20일, 경남과학교육원 신축 공사장에서 당시 경남과학고등학교 교사로 근무하던 백광석(현재 서상중고등학교 교장)에 의해 최초로 발견되어, 수 백 점의 새발자국 화석과 공룡발자국 화석들이 학계에 알려지게 되었다. 지금까지도 세계 여러나라의 중생대 새 발자국 중에서 가장 밀도가 높은 화석산지로 손꼽히고 있으며 많은 학자들의 관심을 받고 있다. 이곳의 지질은 백악기 하양층군 함안층 하부의 적색 이암 또는 셰일과 사암의 호층으로 구성되어 있고, 새발자국 화석들은 적색 이암에서 발견된다. 현재, 이 화석산지는 경남과학교육원 건물 내부에 위치하고 있으며, '화석문화재전시관'이라는 명칭으로 보호 및 관리되고 있기때문에 자연재해와 풍화에 의한 침식을 1차적으로 막고 있다. 이 화석산지는 우리나라에서는 천연기념물 제394호 해남 우항리 화석산지와 함께 현장을 그대로 보존하면서 화석의 보존과 관리를 동시에 할 수 있는 건물을 지어 자연사교육을 진행할 수 있는 곳으로 많은 학생들을 대상으로 우리나라의 소중한 화석을 직접 관찰하고 학습하는 체험교육이 가능하다. 원격조종카메라 시스템을 활용하여 관람객이 직접 자신이 원하는 발자국 화석을 세부적으로 관찰할 수 있게 장치한 interactive system은 과학교육 효과를 증진시킨다. 선행 연구에 의하면, 본 화석산지에서 익룡의 발자국 화석(KS 071)도 공룡이나 새발자국과 같은 층리면에서 서로 겹쳐서 나타난다고 보고되었으나, 본 연구에 의해 다시 조사된 결과 전형적인 익룡의 발자국 화석에서 보이는 분명한 특징들을 발견할 수 없었다. 물갈퀴를 가진 새발자국 가운데에서 Uhangrichnus chuni 와 Jindongornipes kimi 로 기재된 표본들에 대하여서도 새롭게 분석하였다. Uhangrichnus chuni로 기재된 많은 표본들은 II-IV번 발가락 사이의 각, 물갈퀴의 형태, 뚜렷한 hallux 등의 형태적 특징을 근거로 할 때, 대부분이 Ignotorinis yangi로 판단된다. Jindongornipes kimi로 기재된 표본들은 이미 기재된 표본보다 크기가 적어도 10%-25%가 작으며, II-IV번 발가락 사이의 각에서 차이를 보인다.

• Korean Journal of Plant Taxonomy
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• v.45 no.2
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• pp.178-182
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• 2015

Stellaria sessiliflora Y. Yabe (Caryophyllaceae), which is known to be distributed throughout Japan excluding Okinawa, was recently found on Jeju Island in Korea. Reports on the Japanese flora state that this species is distributed on Jeju Island, and a photograph of one specimen (Slide No. 6294) collected from Jeju Island by Ohwi in May 1935 confirms this. Additionally, specimens at the National Arboretum and Korea Forest Research Institute indicate that S. sessiliflora has occurred on Jeju Island for a considerable amount of time. However, the species has never been officially listed in the flora of Korea. Stellaria sessiliflora is distinguished from S. media by having broader leaves with a slightly undulate margin, petiolate leaves on the upper part of the stem, and 10 stamens. The local name 'Geu-Neul-Byeol-Kkot' is given to the species based on its shady habitat under deciduous broadleaf forest. Details of the morphological characters, an illustration, the type specimen, voucher specimen data, and photographs of Stellaria sessiliflora in Korea are presented.

• Journal of Practical Engineering Education
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• v.13 no.2
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• pp.393-403
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• 2021

The purpose of this study is to propose a method of designing a systematic panel survey at the institutional level to lay the foundation for data-based decision-making using vocational training teachers and instructors as the population. In this study, the target population and sampling frame, which are the main elements necessary for planning a panel survey, are proposed. Also based on expert advice and empirical data analysis, the sampling unit and sampling method taking into account the outer and inner variables are presented, comprehensively considering the representativeness of data, the efficiency and sustainability of data collection. As a result of the study, with the unit of the panel as a vocational training institution, a two-stage stratified proportional sampling plan is proposed so that the institution selected as the panel and the vocational training teachers and instructors belonging to the institution can participate in the survey. Based on this, implications for the panel survey sample design are presented.

• Proceedings of the Population Association of Korea Conference
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• 2006.12a
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• pp.193-230
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• 2006

본 논문은 국가별 추계인구와 미래 9개년 인구관련 설명변수들의 추정값을 통하여 적정인구 모형을 구형하고 한국의 적정인구를 추정하는데 목적이 있다. 후생을 고려한 생산함수 확장모형, 세계 176개국의 표본자료 그리고 다중회귀분석을 이용하여 $2000{\sim}2300$년 한국의 적정인구를 추정하고 그 추세곡선을 나타내는 것이다. 모형의 종속변수는 UN에 의한 세계각국의 추계인구이고, 설명변수는 9개 변수 즉 PPP GDP, 인접지역 경제통합율, 교육수준, 영어구사비율, 국토유효면적, 에너지량, 기온, 수자원량, 무역거리이다. 연구결과는 다음과 같다. $2000{\sim}2300$년 한국의 적정인구는 $4,350{\sim}4,950$만명으로 추정되며, 2000년${\sim}$2050년은 $4,700{\sim}5,010$만명, 2050년${\sim}2100$년은 $4,770{\sim}4,400$만명이 된다. 2125년 최저점 4,350만명을 통과한 후 점진적으로 2300년의 4,870만명으로 접근해 갈 것으로 추정된다. 연구결과의 시사점은 네 가지이다. 첫째 한국의 적정인구가 2125년을 기준으로 이전은 감소 이후는 증가 추세일 것이므로 정책결정시 적정한 목표인구를 설정해야 한다는 점이다. 둘째 현 추세로 진행되면 2050년 이후 적정인구가 추계인구보다 $500{\sim}600$만명 더 많아진다는 점이다. 셋째 2125년 이전의 적정인구는 좁게 $4,770{\sim}4,545$만명으로서, 출산율 향상을 통한 적정인구의 유지 노력이 필요하다는 점이다. 넷째 적정인구 추세의 기복은 출산기피로 인한 인구감소 때문으로 출산지원과 입양 및 이민 유입의 정책에 따라 변화될 수 있다는 점이다.

• The Korean Journal of Applied Statistics
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• v.13 no.2
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• pp.515-523
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• 2000

In this paper we detect edges using stutistical methods of the change-point problem. For this, we perform the hypothesis testing for differences in gray levels to see whether any $n\timesn$ subimage contains edge segments. The proposed method based on the twosample Kolmogorov-Smirnov test is introduced and the likelihood ratio test and the \VolfeSchechtman test for change-point problem arc also applied for edge detection. \Ve perform the experimental study to assess the performance of these methods in both noisy and uncontaminated sample noises.