• 응용통계연구
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• 제21권4호
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• pp.615-620
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• 2008

공업실험에서는 주효과의 검정력을 높일 목적으로 교호작용효과에 대한 예비검정의 결과가 유의하지 않은 경우에, 이 효과를 오차항으로 풀링한 후에 주효과의 유의성을 검정하는 때때로 풀링 (Sometimes pooling)의 분석 방법을 사용한다. 이 소고에서는 때때로 풀링의 규칙에 관한 참고문헌의 내용을 정리하고, 블록효과가 오차항으로 풀링되었다는 사실이 알려 졌을 때에 독립표본에 의한 모평균의 차이에 대한 95% 신뢰구간의 길이가 쌍체비교에 의한 신뢰구간의 길이보다 짧을 확률을 다양한 예비검정의 유의수준 ${\alpha}_1$값과 충분한 검정력이 보장되지 않은 블록의 크기인 $2{\leq}n{\leq}13$ 범위에서 살펴보았는데, 그 결과는 풀링한 경우에 주효과에 대한 검정력이 높아진다는 사실을 뒷받침하고 있다.

• Journal of the Korean Data and Information Science Society
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• 제24권6호
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• pp.1263-1274
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• 2013

VaR (value at risk)는 주어진 신뢰수준에서 일정기간 동안 발생할 수 있는 최대손실의 기대치를 나타내는 것으로, 현재 금융기관들의 대표적인 위험관리 수단으로 사용되고 있다. 기존의 대다수 연구에서는 수익률의 확률분포를 정규분포라 모형화한 후 VaR을 측정한다. 최근 Chen 등 (2012)은 수익률의 확률분포를 비대칭 라플라스 분포라 모형화하고 VaR을 측정하였기도 하였으나, 비대칭 라플라스 분포의 경우 그 모양을 결정하는 최빈값, 비대칭 정도, 분산정도 등을 실제적인 환경에서 제한된 개수의 데이터를 가지고 추정하기가 매우 어렵다는 단점이 있다. 이 논문에서, 우리는 (대칭) 라플라스 분포 모형이 정규분포 모형이나 비대칭 라플라스 분포 모형보다 실제적인 환경에서 VaR을 보다 더 정확히 추정해 줌을 주식시장의 실제 데이터와 VaR 초과비율, 기대초과손실, VaR초과편차율 등의 통계지표를 도입하여 입증한다.

• Asian Pacific Journal of Cancer Prevention
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• 제14권2호
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• pp.825-828
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• 2013

Objective: The objective of this study was to determine the five-year survival among patients with cervical cancer treated in Hospital Universiti Sains Malaysia. Methods: One hundred and twenty cervical cancer patients diagnosed between $1^{st}$ July 1995 and $30^{th}$ June 2007 were identified. Data were obtained from medical records. The survival probability was determined using the Kaplan-Meier method and the log-rank test was applied to compare the survival distribution between groups. Results: The overall five-year survival was 39.7% [95%CI (Confidence Interval): 30.7, 51.3] with a median survival time of 40.8 (95%CI: 34.0, 62.0) months. The log-rank test showed that there were survival differences between the groups for the following variables: stage at diagnosis (p=0.005); and primary treatment (p=0.0242). Patients who were diagnosed at the latest stage (III-IV) were found to have the lowest survival, 18.4% (95%CI: 6.75, 50.1), compared to stage I and II where the five-year survival was 54.7% (95%CI: 38.7, 77.2) and 40.8% (95%CI: 27.7, 60.3), respectively. The five-year survival was higher in patients who received surgery [52.6% (95%CI: 37.5, 73.6)] as a primary treatment compared to the non-surgical group [33.3% (95%CI: 22.9, 48.4)]. Conclusion: The five-year survival of cervical cancer patients in this study was low. The survival of those diagnosed at an advanced stage was low compared to early stages. In addition, those who underwent surgery had higher survival than those who had no surgery for primary treatment.

• Journal of Biosystems Engineering
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• 제41권3호
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• pp.193-200
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• 2016

Purpose: New low-cost oilseeds are needed to meet an ever-increasing demand for oil for food, pharmaceutical, and industrial applications. African oil bean seed is a tropical crop that is underutilized and has high oil yields, but there have been no studies conducted on its mechanical oil expression up to now. The objective of this work was to investigate the effect of moisture content and seed dimensions on mechanical oil expression from the seeds. Methods: Fresh oil bean seeds were procured, de-hulled, and cleaned. Initial seed moisture content, obtained in accordance with the ASAE standard, was 12% dry basis (db). The seeds were further conditioned by dehydration and rehydration prior to oil expression to obtain four other moisture levels of 8, 10, 14, and 16% db. The major diameter of the seeds was measured using digital vernier calipers, and the seeds were classified into size dimensions (< 40, 41-45, 46-50, 51-55, and > 55 mm). The oil yield and expression efficiency were obtained in accordance with standard evaluation methods. Results: The highest oil yield and expression efficiency (47.74% and 78.96%, respectively) were obtained for a moisture content of 8% db and seed dimensions of < 40 mm, while the lowest oil yield and expression efficiency (41.35% and 68.28%, respectively) were obtained for a moisture content of 14% db and seed dimensions between 51-55 mm. A mathematical model was developed to predict oil yield for known moisture content and seed dimensions, with a coefficient of determination $R^2$ of 95% and the confidence level of the predictive model of 84.17%. The probability of prediction F ratio showed that moisture content influence was more significant than seed dimensions. Conclusions: The higher the moisture content and larger the seed dimensions, the lower the oil yield from African oil bean seeds.

• 한국도로학회논문집
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• 제19권2호
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• pp.153-165
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• 2017

PURPOSES : With the increasing number of older drivers in an aging society, there is a growing need for research and planning on traffic safety for the older drivers using an improved road geometry design. This study also proposed a modified urban road interchange design, which aims to keep the older drivers away from accident-prone and high-traffic areas of the city. METHODS : In this study, we examined accident data records of older drivers to identify accident-prone zones and intersections; we studied the road geometry at these zones and analyzed if it was an underlying cause for higher number of accidents. Based on the research and subsequent analysis, we suggested plans for improvement of road geometry design at these intersections. RESULTS :By studying historic data and analyzing factors that affect the likelihood of accidents of vehicles driven by older drivers and after studying suitable traffic accident prediction models, we identified the major variables that need to be modified at accident-prone intersections, such as the width of a left turn lane at an intersection and the radius of the right turn lane at a street corner. The results have a significance probability of less than 0.001 and a 95% confidence level. To improve safety at the identified intersection, this study suggests the installation of a left-turn-lane-shaped Positive Offset and a right-turn-lane-shaped Slip Lane concept and an adjustment of intervals between intersections.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제46권4호
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• pp.220-227
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• 2020

Objectives: Papillon-Lefèvre syndrome (PLS) is a rare autosomal recessive disorder. These patients lose their teeth at a young age and are in need of prosthetic rehabilitation. The aim of this systematic review was to assess the success of dental implant placement in these patients. Materials and Methods: An electronic search was performed in PubMed Central, Scopus, and Web of Science using the keyword "Papillon-Lefèvre syndrome" AND "dental implant" OR "prosthodontics". Articles reporting implant placement in patients with PLS until July 2019 were included. Results: Assessment of the included 11 articles reporting 15 cases showed 136 implant placements in these patients. Implant failure occurred in 3 patients (20 implants). The peri-implantitis and failure rate was higher in the maxilla. Meta-analysis showed the probability of failure to be 7% (95% confidence interval [CI] 0%-31%) for maxillary implants and 2% (95% CI 0%-9%) for mandibular implants. The follow-up time ranged between 1 and 20 years. Healing after bone graft and implant placement in these patients was uneventful. Conclusion: Dental implants may be a viable treatment option for PLS patients. Implantation can help preserve alveolar bone if the patients' immunological and growing conditions are well-considered and proper oral hygiene and compliance with the maintenance program are continued.

• Clinical and Experimental Reproductive Medicine
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• 제43권4호
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• pp.207-214
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• 2016

Objective: This study aimed to determine the threshold of $anti-M{\ddot{u}}llerian$ hormone (AMH) as predictor of follicular growth failure in polycystic ovary syndrome (PCOS) patients treated with clomiphene citrate (CC). Methods: Fifty female subjects with PCOS were recruited and divided into two groups based on successful and unsuccessful follicular growth. Related variables such as age, infertility duration, cigarette smoking, use of Moslem hijab, sunlight exposure, fiber intake, body mass index, waist circumference, AMH level, 25-hydroxy vitamin D level, and growth of dominant follicles were obtained, assessed, and statistically analyzed. Results: The AMH levels of patients with successful follicular growth were significantly lower (p= 0.001) than those with unsuccessful follicular growth ($6.10{\pm}3.52$ vs. $10.43{\pm}4.78ng/mL$). A higher volume of fiber intake was also observed in the successful follicular growth group compared to unsuccessful follicular growth group (p= 0.001). Our study found the probability of successful follicle growth was a function of AMH level and the amount of fiber intake, expressed as Y =-2.35+($-0.312{\times}AMH\;level$)+($0.464{\times}fiber\;intake$) (area under the curve, 0.88; 95% confidence interval, 0.79-0.98; p< 0.001). Conclusion: The optimal threshold of AMH level in predicting the failure of follicle growth in patients with PCOS treated with CC was 8.58 ng/mL.

• 디지털융복합연구
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• 제16권1호
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• pp.153-158
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• 2018

본 논문은 인터넷 쇼핑 상품의 허위 사용 후기, 과장 광고, 상품이나 공급업체에 대한 신뢰도 부족 등 커머스 서비스가 가지는 기본적인 문제점을 개선하기 위해 SNS 서비스에 내재된 신뢰형 서비스 개념을 커머스 도메인과 융합하여 "신뢰성 높은 SNS 기반 커머스 서비스"라는 새로운 형태의 시스템을 개발하였다. 본 논문에서 개발된 내용은 첫째, 서비스 제공을 위한 사용자용 커뮤니티 기능과 둘째, 커머스 기능 그리고 셋째, SNS와 커머스 연계 기능 개발이다. 본 논문에서 제시한 신뢰성 있는 상품 정보를 통해 판매자는 상품에 대해 객관적인 안심구매 정보를 구매자에게 제공할 수 있게 되어 실제 구매로 이어지는 가능성을 높여 매출 증대를 기대할 수 있다. 구매자는 안심구매 정보를 이용하여 양질의 제품을 안심하고 구매할 수 있어 만족도가 커지고, 서비스 제공자는 신뢰성 있는 사이트로 구매 회원들에게 알려지게 되어 전자상거래 활성화 및 새로운 커머스 시장 개척에 기여할 것으로 판단된다.

• Clinical and Experimental Pediatrics
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• 제62권11호
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• pp.416-421
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• 2019

Background: The seropositivity rate of hepatitis B surface antigen (anti-HBs) antibodies is known to be ≥95% after hepatitis B virus vaccination during infancy. However, a low level or absence of anti-HBs in healthy children is discovered in many cases. Recent studies in adults reported that a reduced anti-HBs production rate is related to obesity. Purpose: To investigate whether body mass index (BMI) affects anti-HBs levels in healthy children following 3 serial dose vaccinations in infancy. Methods: We recruited 1,200 healthy volunteers aged 3, 5, 7, or 10 years from 4-day care centers and 4 elementary schools. All subjects completed a questionnaire including body weight, height, and vaccine type received. Levels of serum hepatitis B surface antigen (HBsAg) and anti-HBs in all subjects were analyzed using electrochemiluminescence immunoassay. The standardized scores (z score) for each sex and age were obtained using the lambda-mu-sigma method in the 2017 Korean National Growth Charts for children and adolescents. Results: Our subjects (n=1,200) comprised 750 males (62.5%) and 450 females (37.5%). The overall anti-HBs seropositivity rate was 57.9% (695 of 1,200). We identified significant differences in mean BMI values between seronegative and seropositive groups (17.45 vs. 16.62, respectively; P<0.001). The anti-HBs titer was significantly decreased as the BMI z score increased adjusting for age and sex (B=-15.725; standard error=5.494; P=0.004). The probability of anti-HBs seropositivity based on BMI z score was decreased to an OR of 0.820 after the control for confounding variables (95% confidence interval, 0.728-0.923; P=0.001). Conclusion: There was a significant association between anti-HBs titer and BMI z score after adjustment for age and sex. Our results indicate that BMI is a potential factor affecting anti-HBs titer in healthy children.

• 한국전산구조공학회논문집
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• 제21권3호
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• pp.275-280
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• 2008

신뢰성 기반 형상 최적화(RBDO)글 위한 기술은 한정된 정보로 인한 인식론적 불확실성을 다룰 수 있는 베이지안 접근에 근거하여 발달된다. 최근까지, 전통적인 RBDO는 측정 데이터가 무한히 많아서 확실한 확률정보를 알고 있다는 가정 하에 실행되었다. 하지만 실제로는, 부족한 데이터로 인해 기존의 RBDO 방법의 유용성을 떨어뜨린다. 본 연구에서는, 확률정보의 불확실성을 인식하고, 따라서 산포를 갖게 되는 시스템 신뢰도의 확률 분포에서의 신뢰수준의 하한 값을 고려하기 위해 '베이지안 신뢰성'이 소개된다. 이런 경우, 베이지안 신뢰성 해석은 기존 신뢰도 해석의 이중 해석을 요구하게 된다. 크리깅 기반 차원 감소 방법(KDRM)은 신뢰도 해석을 위한 새로운 효율적인 방법으로써 사용되며, 제시된 방법은 몇 가지 수치예제를 사용하여 설명된다.