• 펄프종이기술
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• 제34권5호
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• pp.1-17
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• 2002

The immobilization and consolidation of the model coatings based on the plastic pigment and latex binder of known particle sizes were theoretically Studied in terms of the dense random packing of binary spheres and varying extent of latex film shrinkage. The porosity of the model coatings was calculated based on three proposed latex shrinkage models: Maximum, Minimum, and Linearly Decreasing Latex Shrinkage. The increasing extent of latex shrinkage was calculated up to the critical pigment volume concentration(CPVC) as a function of plastic pigment volume fractions, and the maximum latex shrinkage was estimated from the CPVC. Also, the number of pores and the average equivalent spherical pore diameters were calculated based on those proposed models. The opacity and gloss of the model coatings on polyester films were measured and their porosity was also determined by a simple coat weight-thickness method. As expected, various coating structure-property-composition relationships, such as opacity, gloss, porosity, etc., were shown to exhibit sharp transitions near the CPVC. The CPVC values determined by the opacity, gloss, and porosity vs. PVC relationships, respectively, agreed very well with each other. Especially, the CPVC's determined by the opacity and porosity vs. PVC curves were identical. The comparison between the theoretically calculated and experimental porosity values showed that the intermediate value between the maximum and minimum latex shrinkage would best fit the experimental porosity data. The effect of plastic pigment particle size on the optical properties and porosity of model coatings was also studied and it was observed that the coating opacity and porosity increased with increasing plastic pigment particle size, but the gloss decreased. The ink gloss of the uncalendered model coatings applied onto commercial sheet offset coated papers was shown to be affected by both the coating gloss and porosity: the higher the coating gloss, the higher the ink gloss, but the higher the coating porosity, the lower the ink gloss. Their printability was also studied in terms of the number of passes-to-fail and the rate of ink setting as a function of both plastic pigment volume fractions and plastic pigment particle sizes. A minimum crack-free temperature(MCR) of latex-bound coatings was proposed to better predict the behaviors of latexes as coating binders. The wet state of model coating dispersions, the surfaces of consolidated model coatings, and their internal structure were examined by both electron and atomic force microscopy, and their micrographs were found to be consistent with our immobilization and consolidation models.

• Journal of the Korean Data Analysis Society
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• 제20권6호
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• pp.2829-2840
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• 2018

음이 아닌(non-negative) 측정값을 가지는 확률변수에 있어서, 영(0)이 과도하게 측정되는 자료를 반연속형(semi-continuous) 자료와 영-과잉(zero-inflated) 자료로 구분한다. 이러한 자료에서는 특정 확률 분포(probability distribution) 하에서의 확률보다 훨씬 큰 확률로 0을 관측하게 되는데, 연속형(continuous) 확률분포를 고려하는 경우에는 반연속형으로, 이산형(discrete) 확률분포를 고려하는 경우에는 영-과잉이라고 한다. 본 연구에서는 경계값(0)의 측정 여부에 관한 모형과 0보다 큰 확률변수에 대한 확률분포를 활용한 모형 등 두 개의 부문으로 이루어진 모형, 즉 2-부문 모형(two-part model)을 소개하고자 한다. 특히, 이산형 확률분포 중 포아송 분포와 음이항 분포를 고려한 영-과잉 회귀모형(regression model)을 설명하고 그 특성을 파악하고자 한다. 실증연구에서는 이러한 영-과잉 회귀모형을 활용하여 지난 10년(2009년부터 2018년) 간 한국의 여름철(6-8월) 폭염주의보(heat-wave advisory) 및 폭염경보(heat-wave warning) 발생일수를 적합하였다. 또한 공간예측기법 중 하나인 범용크리깅(universal kriging)을 이용하여 적합결과를 바탕으로 한 폭염 발생일수에 대한 예측지도를 작성하였다.

• 생명과학회지
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• 제32권10호
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• pp.821-831
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• 2022

본 연구의 목적은 아동의 신체접촉놀이를 중재로 한 선행 연구들을 체계적 문헌고찰 및 메타분석을 통해 그 효과를 분석하고자 함이다. 본 연구는 국내 주요 DB를 이용하여 논문 검색을 하였으며 1,544편 중 선정기준에 적합한 최종 7편의 논문을 체계적 문헌고찰을 하였으며 7편의 논문에서 제시된 20개의 중재를 대상으로 메타분석을 실시하였다. 연구출처는 KERIS, KISS, DBpia, SciencON을 통해서 2022년 8월까지 출판된 연구를 분석하였다. 연구대상이 되는 주요어는 아동, 유아, 신체접촉, 신체접촉놀이, 신체접촉활동, 신체접촉놀이 프로그램 등이다. 분석은 랜덤효과모형을 이용하였으며, 신체접촉 프로그램의 효과크기를 산출하였다. 본 연구에서 신체접촉놀이 프로그램에 대한 효과 크기는 Hedges' g=6.20(95% CI: 3.74-8.66)로 큰 효과크기를 보였으며, 전체 이질성이 I2=95.4% (Q=417.30, p<.001)로 나타나 총 중재횟수와 중재기간을 조절변수로 하여 조절효과를 분석하였다. 분석결과 총 중재횟수에서는 유의한 차이가 있었고 중재기간에서는 유의한 차이가 없었다. 본 연구는 우리나라 아동의 신체접촉놀이 프로그램의 효과에 대한 국내 연구결과들을 체계적으로 분석하고, 그 효과 크기를 객관적으로 제시하여 향후 신체접촉놀이 프로그램을 설계할 때 기초자료를 제공하였다는데 의의가 있다. 연구결과를 바탕으로 신체접촉놀이 프로그램의 효과에 대한 근거자료를 확보하기 위해 추후 연구가 필요하다고 사료된다.

• 지역연구
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• 제37권4호
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• pp.49-59
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• 2021

이 연구의 목표는 정비사업(재개발, 재건축사업)이 해제된 지역의 특성을 파악하는 것이다. 이 연구의 범위는 189개의 사업구역(추진구역 121개, 해제구역 68개)이다. 121개의 추진구역과 68개의 해제구역은 모두 의사결정나무기법으로 분석하였다. 해제구역 영향요인에 대한 첫 번째 분리는 추진주체 유무에 의해 이루어졌다. 즉, 해제구역 영향요인을 결정하는 가장 중요한 독립변수는 추진주체 유무로 나타났다. 추진주체가 없는 89개 구역 중 41개 구역이 해제되고 48개 구역이 추진되었으며, 추진주체가 있는 100개 구역 중에 9개 구역이 해제되고 91개 구역이 추진되었다. 그 다음 해제구역 영향요인에 대한 두 번째 분리는 토지등소유자 수에 의해 이루어 졌으며, 토지등소유자 수가 468명 이하인 경우 해제확률이 늘어났으며, 62개 구역 중 37개 구역이 해제되었다. 반면 토지등소유자 수가 468명 이상인 27개 구역은 4개 구역이 해제되고 23개 구역이 추진되었다. 세 번째 분리는 평균공시지가에 의해 이루어졌으며, 269.64 만원/m²(대략 평당 891만원)을 기준으로 이하에서는 35개 구역이 해제되었고, 더 높은 공시가격에서는 2개 구역이 해제되었다. 한편, 두 번째 분리에서 토지등소유자 수가 468명 이상으로 사업추진 방향으로 분리된 node4에서는 토지등소유자 당 국공유지 면적 비율이 29.43% 이상인 구역에서 4개 구역이 해제되었고, 그 이하인 구역에서 해제가 없었다. 이 연구를 위한 통계, 의사결정나무분석에는 IBM SPSS Statistics 26 프로그램이 사용되었다.

• 지능정보연구
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• 제28권4호
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• pp.347-364
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• 2022

고객의 구매 의사결정에 영향을 주는 온라인 리뷰의 부적절한 조작을 통해 이익을 얻고자 하는 기업 또는 온라인 판매자들 때문에, 리뷰의 신뢰성은 온라인 거래에서 매우 중요한 이슈가 되었다. 온라인 쇼핑몰 등에서 온라인 리뷰에 대한 소비자들의 의존도가 높아짐에 따라 많은 연구들이 조작된 리뷰를 탐지하는 방법에 개발하고자 하였다. 기존의 연구들은 온라인 리뷰를 기반으로 정상 리뷰와 조작된 리뷰를 대상으로 기계학습으로 이용함으로써 조작된 리뷰를 탐지하는 모형을 제시하였다. 기계학습은 데이터를 이용하여 이진분류 문제에서 탁월한 성능을 보여왔으나, 학습에 충분한 데이터를 확보할 수 있는 환경에서만 이러한 성능을 기대할 수 있었다. 조작된 리뷰는 학습용으로 사용할 수 있는 데이터가 충분하지 못하며, 이는 기계학습이 충분한 학습을 할 수 없다는 치명적 약점으로 내포하게 된다. 본 연구에서는 기계학습이 불균형 데이터 셋으로 인한 학습의 저하를 방지할 수 있는 방안으로 부족한 조작된 리뷰를 인공지능을 이용하여 생성하고 이를 기반으로 균형된 데이터 셋에서 기계학습을 학습하여 조작된 리뷰를 탐지하는 방안을 제시하였다. 파인 튜닝된 GPT-3는 초거대 인공지능으로 온라인 플랫폼의 리뷰를 생성하여 데이터 불균형 문제를 해결하는 오버샘플링 접근방법으로 사용되었다. GPT-3로 생성한 온라인 리뷰는 기존 리뷰를 기반으로 인공지능이 작성한 리뷰로써, 본 연구에서 사용된 로짓, 의사결정나무, 인공신경망의 성능을 개선시키는 것을 SMOTE와 단순 오버샘플링과 비교하여 실증분석을 통해서 확인하였다.

• 디지털융복합연구
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• 제20권3호
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• pp.41-52
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• 2022

국내 공공도서관은 1, 2차 도서관 발전 종합계획을 토대로 양적 성장을 이루었으나, 질적으로는 다소 부족한 점이 있어 이를 개선하기 위한 다양한 연구가 수행되었다. 대다수 선행연구에서는 사회·경제적 요인과 통계분석에 한정되어 수행된 한계점이 있다. 이에 본 연구에서는 시공간적 개념을 적용하여 강우와 폭염으로 인한 공공도서관 대출 수요 감소를 정량적으로 산출하고, 기상 변화로 도서 대출 수요 감소가 높은 지역과 그렇지 않은 지역을 군집화하여 공공도서관 내·외부 요인들과 결합한 후 기상변화에 따른 공공도서관 대출 수요 변화를 분석하였다. 분석 결과 공공도서관별 기상으로 인한 감소 차이가 존재하였으며, 공공도서관의 특성과 공간적 위치에 따라 일부 다르게 나타났다. 또한, 기온이 35℃ 이상인 폭염일 경우 도서 대출 수요 감소 폭이 많이 증가하였으며, 랜덤포레스트 모형으로 분석한 결과 유의미한 요인이 도출되었다. 내적 요인으로는 좌석 수, 장서 수, 면적이 도출되었으며, 외적 요인으로는 공공도서관 접근 경사로, 카페, 독서실, 10대 유동인구, 30/40대 여성 유동인구가 중요한 변수로 분석되었다. 이러한 분석 결과는 특정 시즌 기상을 고려한 공공도서관 이용 활성화 정책 수립에 이바지할 것으로 판단되며, 연구의 한계점도 제시하였다.

• 항공우주시스템공학회지
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• 제18권1호
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• pp.11-20
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• 2024

최근 뉴스페이스 시대에는 과거의 고신뢰성 위성과 다르게 낮은 신뢰성 위성을 저가의 개발/양산 비용으로 개발하여 군집위성을 발사하고 있다. 경제적인 군집위성 개발을 위해서는 위성 사용자/개발자는 군집위성으로 발사되었을 때 기대되는 수명기간 동안 임무 성능의 유지 가능성 여부를 검토해야 한다. 또한, 성능유지를 위해 임의 고장에 의한 교체 계획도 수립되어야 한다. 본 연구에서는 지구관측 군집위성의 임무 성능의 유지와 교체 전략 수립을 위해 시스템 신뢰성 및 가용성 평가 방법을 제안하였다. 본 연구에서는 위성 백업 및 지상 추가 발사 백업 상황과 군집위성에 요구되는 임무 성능을 고려한 군집위성 신뢰성 및 가용성 모델을 구성하였다. 신뢰성 모델은 k-out-of-n system의 개념으로 구성되었고 가용성 모델은 마르코프 체인 모델을 이용하였다. 제안된 신뢰성 모델을 바탕으로 임무 요구사항에 필요한 최소 위성 개수를 정의하고, 요구 임무기간 동안 요구 임무 신뢰성 만족을 위해 궤도상 필요한 위성을 계산하였다. 또한 가용성 분석을 통해 요구 서비스기간 동안 요구 가용성 만족을 위한 궤도상 위성 여분 및 지상 여분의 개수를 분석하였다. 마지막으로 비용모델을 적용하여 위성의 신뢰성 및 개발 위성 개수간에 절충분석 개념을 제안하였다.

• 한국치위생학회지
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• 제8권2호
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• pp.39-51
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• 2008

The research was conducted to 100 child patients selected by random sampling, which got a Dentocult-SM test in the first visit and then was being continuously managed, out of child patients of a pediatric clinic located in Gyeonggi-do. The period of there search is one year from June 2007 to May 2008, Using Dentocult-SM test, we analyzed the correlation between the distribution of dental plaque, a streptococcus mutans in saliva and condition of dental caries cavity in the teeth of child patients, then we measured the distribution of a streptococcusmutans. According to SM score, we applied incremental oral heath care for child patients to clinical and obtained the following results, 1. In terms of the age of child patients in research, the number of 3 years old patients was 29(lst ranked), the number of 2 years old patients was 28(2nd ranked). 2. The result of SM score showed that female child patients(52.0%) was higher than male ones in negative, male child patients(52.0%) was higher than female ones in mild, female child patients(68.2%) was higher than male ones in moderate, male child patients(57.1%) was higher than female ones in severe. 3. At the first visit, the SM score showed statistically remarkable difference between dt and dmft. We can also confirm the average of severe is the highest. 4. At the second visit, the SM score showed statistically remarkable difference among dt, ft, and dmft index We can also confirm the average of severe is the highest. 5. At the third visit, The SM score showed statistically remarkable difference among dt, ft, and dmft index We can also confirm the average of severe is the highest. 6. The comparison of dmft index differences to SM score showed statistically no remarkable difference in incremental oral heath care for negative and mild, In addition to that, we can confirm that the incremental oral heath care makes statistically remarkable differences in moderate and severe. 7. The comparison of dt index differences to SM score showed statistically no remarkable difference in incremental oral heath care for negative, mild, and moderate, In addition to that, we can con firm that the incremental oral heath care makes statistically remarkable differences in severe. 8. The comparison of mt index differences to SM score showed statistically no remarkable difference in incremental oral heath care for mild and moderate, In addition to that, we can confirm that the incremental oral heath care makes statistically remarkable differences m severe. 9. The comparison of ft index differences to SM score showed statistically no remarkable difference in incremental oral heath care for mild, In addition to that, we can confirm that the incremental oral heath care makes statistically remarkable differences in negative, moderate, and severe. 10. According to the comparison of dmft index to the age, the 4 years old patients showed the highest number(5.50 in the first visit and 6,08 in the second one). In the third visit, the 6 years old patients showed the highest number(7.00). By the above results, we can find that the incremental oral heath care by SM score makes the results of oral care better. Therefore, the improvement or maintenance in oral health of child patients needs continuing personal oral health management and regular systematic management focused on prevention by the specialist.

• 한국병원경영학회지
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• 제9권1호
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• pp.66-94
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• 2004

The objective of this study is to examine how to maximize the efficiency of hospital management by minimizing the unit cost of hospital operation. For this purpose, this paper proposes to develop a model of the profit maximization based on the cost minimization dictum using the statistical tools of arriving at the maximum likelihood values. The preliminary survey data are collected from the annual statistics and their analyses published by Korea Health Industry Development Institute and Korean Hospital Association. The maximum likelihood value statistical analyses are conducted from the information on the cost (function) of each of 36 hospitals selected by the random stratified sampling method according to the size and location (urban or rural) of hospitals. We believe that, although the size of sample is relatively small, because of the sampling method used and the high response rate, the power of estimation of the results of the statistical analyses of the sample hospitals is acceptable. The conceptual framework of analyses is adopted from the various models of the determinants of hospital costs used by the previous studies. According to this framework, the study postulates that the unit cost of hospital operation is determined by the size, scope of service, technology (production function) as measured by capacity utilization, labor capital ratio and labor input-mix variables, and by exogeneous variables. The variables to represent the above cost determinants are selected by using the step-wise regression so that only the statistically significant variables may be utilized in analyzing how these variables impact on the hospital unit cost. The results of the analyses show that the models of hospital cost determinants adopted are well chosen. The various models analyzed have the (goodness of fit) overall determination (R2) which all turned out to be significant, regardless of the variables put in to represent the cost determinants. Specifically, the size and scope of service, no matter how it is measured, i. e., number of admissions per bed, number of ambulatory visits per bed, adjusted inpatient days and adjusted outpatients, have overall effects of reducing the hospital unit costs as measured by the cost per admission, per inpatient day, or office visit implying the existence of the economy of scale in the hospital operation. Thirdly, the technology used in operating a hospital has turned out to have its ramifications on the hospital unit cost similar to those postulated in the static theory of the firm. For example, the capacity utilization as represented by the inpatient days per employee tuned out to have statistically significant negative impacts on the unit cost of hospital operation, while payroll expenses per inpatient cost has a positive effect. The input-mix of hospital operation, as represented by the ratio of the number of doctor, nurse or medical staff per general employee, supports the known thesis that the specialized manpower costs more than the general employees. The labor/capital ratio as represented by the employees per 100 beds is shown to have a positive effect on the cost as expected. As for the exogeneous variable's impacts on the cost, when this variable is represented by the percent of urban 100 population at the location where the hospital is located, the regression analysis shows that the hospitals located in the urban area have a higher cost than those in the rural area. Finally, the case study of the sample hospitals offers a specific information to hospital administrators about how they share in terms of the cost they are incurring in comparison to other hospitals. For example, if his/her hospital is of small size and located in a city, he/she can compare the various costs of his/her hospital operation with those of other similar hospitals. Therefore, he/she may be able to find the reasons why the cost of his/her hospital operation has a higher or lower cost than other similar hospitals in what factors of the hospital cost determinants.

• 한국치위생학회지
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• 제7권2호
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• pp.135-151
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• 2007

The purpose of this study was to examine the work environments of dental hygienists, to find out about what problems there were with their work environments and ultimately to help improve their work environments. It's basically intended to pave the way for furthering the welfare and interests of dental hygienists. The subjects in this study were dental hygienists who were selected by random sampling from among the members of Korean Dental Hygienists Association. Approximately 20 percent of the members each were selected from every region across the nation, and their work environments were investigated in consideration of the kind of their workplaces, service area, career and field of duties. As for the demographic characteristics of the dental hygienists investigated, there were differences between those who worked in the field of health care and the clinical workers. More of the former were older and married, and the former was ahead of the latter in career and education as well. Regarding working hours and leave of absence by kind of workplace, the number of regular average holidays was different according to their place of employment. Dental hospitals(6.66 days) and dental clinics(6.81 days) gave their employees less days off on the whole, whereas public dental clinics(19.29 days) granted the dental hygienists the longest leave of absence. Also, there was a broad gap in the number of regular average holidays among different regions in the nation. The dental hygienists who worked in Gangweon province enjoyed the longest holidays(10.88 days), while those on Jeju Island took the shortest vacation(4.46 days). Concerning monthly mean pay by place of employment, those who worked in public dental clinics were paid the best, and the dental hospital employees received the smallest pay. Their monthly mean pay significantly varied with the kind of their workplaces. As to connections between service area and pay level in the event of the dental hygienists with a four-year career, those who served in Seoul were paid the best(1,820,800 won), followed by Gyeonggi province(1,795,800 won), Gyeongsang province(1,604,200 won), metropolitan cities(1,424,800), Gangweon province(1,300,000 won) and Jeolla province(1,016,700 won). In regard to the starting pay in the different areas, the starting pay was largest in Seoul(1,501,800 won) and smallest in Jeolla province(904,000 won). Concerning work environments by place of employment, the dental hygienists in public dental clinics, general hospitals and university hospitals were far older than the others, and the career of the former was much larger than that of the latter. As to the number of regular leave of absence, public dental clinics, general hospitals and university hospitals were different from dental hospitals and clinics in that regard as well. Concerning monthly pay, public dental clinics paid their employees the best, and dental hospitals and clinics were ahead in terms of pay raise. But the reason seemed that public dental clinics and general hospitals increased the pay of their employees based on a fixed wage system and according to a fixed rate at the same time. As for relations between career and work environments, the pay of the dental hygienists differed with their career. The amount and rate of pay raise were largest for those whose career was between four years and less than six years, and smallest for those whose career was between seven years and less than nine years. The above-mentioned findings of the study suggested that in order to give dental hygienists better treatment, pay and welfare benefits should urgently be improved, and that it's required to take actions to boost their job satisfaction. Besides, they should be given more chances to receive education or to take training courses in pursuit of self-development, and how to narrow gaps in work environments among different regions or fields should carefully be considered.