• 응용통계연구
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• 제36권4호
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• pp.323-335
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• 2023

고차원 데이터의 인과 추론에서 고차원 공변량의 차원을 축소하고 적절히 변형하여 처리와 잠재 결과에 영향을 줄 수 있는 교란을 통제하는 것은 중요한 문제이다. 평균 처리 효과(average treatment effect; ATE) 추정에 있어서, 성향점수와 결과 모형 추정을 이용한 확장된 역확률 가중치 방법이 주로 사용된다. 고차원 데이터의 분석시 모든 공변량을 포함한 모수 모형을 이용하여 성향 점수와 결과 모형 추정을 할 경우, ATE 추정량이 일치성을 갖지 않거나 추정량의 분산이 큰 값을 가질 수 있다. 이런 이유로 고차원 데이터에 대한 적절한 차원 축소 방법과 준모수 모형을 이용한 ATE 방법이 주목 받고 있다. 이와 관련된 연구로는 차원 축소부분에 준모수 모형과 희소 충분 차원 축소 방법을 활용한 연구가 있다. 최근에는 성향점수와 결과 모형을 추정하지 않고, 차원 축소 후 매칭을 활용한 ATE 추정 방법도 제시되었다. 고차원 데이터의 ATE 추정 방법연구 중 최근에 제시된 네 가지 연구에 대해 소개하고, 추정치 해석시 유의할 점에 대하여 논하기로 한다.

• 분석과학
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• 제8권4호
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• pp.465-468
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• 1995

Matrix assisted laser desorption ionization in mass spectrometry is a fast and accurate method to determine the molecular weight of natural and synthetic polymers. Unknown peptides such as elastase inhibitor and $\small{D}$-hydantoinase were analyzed using sinapinic acid as matrix and their molecular weights were compared with the results from protein sequencer and gel filtration chomatography, respectively. Synthetic polymers such as polyethyleneglycol, polypropyleneglycol, polydimethylsiloxane, and polystyrene were analyzed using matrices such as 2,5-dihydroxybenzoic acid, 4-hdroxyazobenzenecarboxylic acid, and 2-nitrophenyl octyl ether. Average molecular weights of polystyrene were compared with molecular weights by gel permeation chromatography.

• 공업화학
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• 제33권6호
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• pp.661-665
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• 2022

In this study, 2,5-dichlorobenzophenone was synthesized as a monomer using 1,4-dichlorbenzene, and subsequently, copolymers of benzoyl-p-phenylene and p-phenylene were prepared. The average molecular weight was improved using the low-molecular-weight polymer cutting method. The average molecular weight and glass transition temperature of the synthesized polymers were estimated. The as-prepared polymer was used as a hard coating material, and the coating was conducted on a poly(methyl methacrylate) plate. Furthermore, physical properties of the coatings, such as pencil hardness, adhesive strength, and abrasion resistance, were estimated. As the amount of p-phenylene in the copolymer increased, pencil hardness and abrasion resistance improved. The amount of p-phenylene in the copolymer can be increased to 30 mol% in order to increase the hardness of the coating, and the adhesive strength was insufficient for the copolymers with p-phenylene ratio greater than 35 mol%.

• 한국인터넷방송통신학회논문지
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• 제19권5호
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• pp.151-155
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• 2019

최근 심근경색은 중장년층의 돌연사의 80%로 밝혀졌다. 심근경색의 발병 원인은 복합적이고 갑자기 발생하게 되어 예방이나 건강검진을 하더라도 발병을 예측하기 어렵다. 따라서 빠른 진단과 적절한 치료가 가장 중요하다. 이 논문에서는 심근경색에 대한 정확하고 빠른 진단을 위해 가중퍼지소속함수를 이용한 신경망으로 정상과 비정상 분류에 대한 정확도를 나타내었다. 실험에 사용된 데이터는 14개의 특징과 303개의 샘플 데이터로 이루어진 UCI Machine Learning Repository에서 제공하는 데이터 사용하였다. 2개의 특징을 선택하여 제거하였다. 특징선택을 위한 알고리즘은 average of weight method를 사용하였다. 가중퍼지소속함수를 이용하여 심근경색을 정상과 비정상으로 분류(1-nomal, 2-abnormal)하였다. 실험 결과 정확도가 87.66%가 나왔다.

• 한국생활과학회지
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• 제9권2호
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• pp.231-243
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• 2000

This study was conducted to investigate the relationship between body image and BMI with satisfaction of own body image, snack intake practices, food intake practices and weight control practices of 226 female college students in Jeonbuk province using questionnaire. The results were summarized as follows : 1. The average height, weight and BMI was 162.08cm, 52.02kg and 19.78, respectively. The average ideal body weight of the subjects was 48.92kg. Ninety percent of the subjects was dissatisfied with their body image. The degree of dissatisfaction was higher in the group who recognized themselves as fat. Most of subjects wanted to lose weight, but as the group having a recognition of thin body image significantly wanted to gain weight (p<0.001). 2. The subjects preferred fruits and juices for snack. The more subjects recognized themselves as fat, the more they restricted snack intake (p<0.05). 3. The rate of skipping meal tends to increase. The subjects did not intake balanced meals and skipped breakfast most (20.7%). The number of food groups taken at breakfast, lunch and dinner was 1.84, 2.25 and 2.55, respectively and the most variable food groups were taken at dinner(p<0.001). Dairy food group intake was low. The duration of meal time was longer in the underweight group by BMI regardless of body image recognition (p<0.05). 4. The weight controlling method was concentrated mostly on decreasing food intake. The more subjects recognized themselves as fat, the more they tried to control weight (p<0.001). Even though 59.5% of the subjects with no weight control experience had no future weight control plans, 50% of the group who recognized themselves as normal or fat did not want to control weight in the future (p<0.01). These results suggest that nutrition education programs and correction programs of food behaviors and weight control should start from focusing on the accurate recognition of body image for college female students.

• Journal of Nutrition and Health
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• 제30권5호
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• pp.506-511
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• 1997

In order to investigate the body weight change and human milk intake of breast-fed infants, we examined thirty-three infants with test-weing method in Sokcho area during the first 5 months of lactation. The average birth weight of infants was 3300g. They grew 3300, 3805, 4676, 5878, 6786, 7403, and 8111g when they became 0.5, 1, 2, 3, 4, and 5 months old. The is human milk intake was 515, 650, 718, 731, 746 and 796g/day during the lactatin. Human milk intake of boys was significantly higher than that of girls at 1(p<0.05), 2(p<0.01), and 3(p<0.01) months of lactation. During lactatin, the number of feedings per day decrerased. The human milk intakes per feeding had increased from 54.4g at 0.5 months to 98.9g at 5 months of lactation The human milk intake on infants was not affected by gestational period and birth weight. From this survey, we found a difference between boys and girls in human milk intake.

• 대한방사선기술학회지:방사선기술과학
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• 제33권4호
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• pp.349-354
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• 2010

2010년 3월부터 6월까지 I병원과 N병원에서 22명을 대상으로 DXA와 QCT에 의한 동일개체에서의 요추골밀도를 측정하여 비교분석하였고, 통계학적인 방법으로는 SPSS for Windows 프로그램(version 12.0)을 사용하여 빈도분석과 t-test로 골밀도와 연령, 신장, 체중의 상관관계를 분석하여 다음과 같은 결과를 얻었다. 연구대상자의 분포는 남자 19명, 여자 3명으로 모두 22명이며, 연령은 28세 부터 37세로 분포하였다. 평균연령은 32.14세이고, 이들의 평균신장은 170.59 cm이며, 평균체중은 69.41 kg으로 나타났다. 또한 DXA방법과 QCT방법에 의한 층위별 평균골밀도는 L2-L4에서 상관계수가 0.378로 뚜렷한 양적 상관관계가 나타났다. 연령별 분석에서는 QCT방법보다는 DXA방법이 10.8% 더 유용한 것으로 나타났고, 신장별 분석에서는 DXA방법보다는 QCT방법이 3.4% 더 유용한 것으로 나타났으며, 체중별 분석에서는 DXA방법보다는 QCT방법이 1.2% 더 유용한 것으로 나타났다. 이상의 본 연구 결과에서 골밀도 측정에 있어서 연령별에서는 DXA방법이 유용하고, 신장과 체중별에서는 QCT방법이 다소 유용한 것으로 나타났다. 따라서 골밀도 측정에 있어 환자의 연령, 신장, 체중 등에 따라 정확한 측정방법의 선택이 고려되어야 할 것으로 사료된다.

• 한국환경보건학회지
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• 제29권4호
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• pp.27-34
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• 2003

Bisphenol A is used in the manufacture of epoxy, polycarbonate, and corrosion-resistant unsaturated polyester-styrene resins required for food packaging materials in industrial processing. Some reports indicated the possibility of harmful effects on rats. In this study was used a method for the determination of bisphenol A in blood according to the OSHA High Performance Liquid Chromatography (HPLC) guideline. The method involved blood extraction using methylene chloride. And it was evaluated developmental and teratogenic effects in pregnant rats and second generation. The results obtained were as follows. There was a significant increase in the body weights and treated groups F1 female in liver, spleen, kidney, but according to dose-response. F1 female rat's relative body weight and absolute body weight are not different. There was a significant increase liver, spleen, kidney organ weight and reproductive organ weight epididymis, prostate gland in F1 male rats. There was a proestrous in pregnant rat, group 200 $\mu\textrm{g}$/kg, 2000 $\mu\textrm{g}$/kg, 20,000 $\mu\textrm{g}$/kg. The effect on rat treated with bisphenol A decrease organ weight and reproductive organ weight. Identification and quantitation were performed with using HPLC C18 column and using at retention time 5.5 min. The results of the detection of bisphenol A were at 20,000 $\mu\textrm{g}$/kg in average 1 $\mu\textrm{g}$/ml, 200 $\mu\textrm{g}$/kg average in 0.9 $\mu\textrm{g}$/ml blood samples. From those results, it could be concluded that the effects of pregnant rat and second generation(F1) by bisphenol A treatment during lactational period were estrogenic and bisphenol A was remained in serum at low level.

• 대한전기학회논문지:시스템및제어부문D
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• 제51권3호
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• pp.112-121
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• 2002

This paper describes a new bike system for the postural balance rehabilitation training. Virtual environment and three dimensional graphic model is designed with CAD tools such as 3D Studio Max and World Up. For the real time bike simulation, the optimized WorldToolKit graphic library is embedded with the dynamic geometry generation method, multi-thread method, and portal generation method. In this experiment, 20 normal adults were tested to investigate the influencing factors of balancing posture. We evaluated the system by measuring the parameters such as path deviation, driving velocity, COP(center for pressure), and average weight shift. Also, we investigated the usefulness of visual feedback information by weight shift. The results showed that continuous visual feedback by weight shift was more effective than no visual feedback in the postural balance control It is concluded this system might be applied to clinical use as a new postural balance training system.

• 복식문화연구
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• 제2권2호
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• pp.385-394
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• 1994

Data of the body surface is a necessary unit for the measuring of metabolism energy and activity energy. And also, these data are referring to check the degree of retaining warmth of clothes, to find the effect of heat insulation according to body surface, to calculate an average temperature of skin, and to study the several fields of clothing. In measuring of body surface, it si actually impossible to measure a subject's body surface in each experiment. As the experimental method, both gypsum method, by which the shape of body an be copied as it is, and the weighting method from which planed body surface area can be measured with consistent thickness of polyprophylene film as used. In fact, every female subject feels uncomfortable to measure her body surface as a naked body. There, it is providing a simple, accurate regressive equation with weight & height as variable factors in this study. This equation is as=117.02W+77.31H-3344.94 with average error : 0.1%, absolute average error : 2.07%.