• Journal of Preventive Medicine and Public Health
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• 제32권1호
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• pp.60-64
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• 1999

환경오염과 관련된 건강효과 연구에서 흡연, 직업 등 교란변수의 영향을 효과적으로 배제할 수 있으면서 폐기능검사가 제대로 시행될 수 있는 연구대상으로 선호되고 있는 특정 연령층인 12세 학동의 보다 정확한 FVC와 FEV1 예측식을 만 들고자 전국 11개 중학교의 학생들(남자 256명, 여자 301명)을 대상으로 측정된 신장, 체중, 그리고 폐기능검사 값으로 신장-체중의 회귀식을 유도하였고, 이를 통해 12세 인구의 신장별 표준체중을 산출하였다. 이 표준체중과 실측체중의 차이인 잔차를 독립변수로 하여 폐기능 예측 식을 남녀별로 만들었는데, 남자의 경우는, FVC(ml) = 50.84 $\times$ 신장(cm) + 7.06 $\times$ 체중 잔차 - 4838.86, FEV1(m1) = 43.57 $\times$ 신장(cm) + 3.16 $\times$ 체증 잔차 4156.66 이었다. 여자에서는 FVC(ml) = 42.57 $\times$ 신장(cm) + 12.50 $\times$ 체중 잔차 - 3862.39, 그리고 FEV1(ml) = 36.29 $\times$ 신장(cm) + 7.74 $\times$ 체중 잔차 - 3200.94 이었다. 이렇게 얻어진 예측값들의 설명력(R2)은 남자에서 FVC, FEV1가 각각 0.708, 0.670이었고, 여자에서는 FVC, FEV1가 각각 0.580, 0.513이었다.

• 동력기계공학회지
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• 제9권2호
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• pp.106-111
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• 2005

After many casualties of conventional bulk carriers in recent years, a double hull bulk carrier was proposed to enhance the structural safety of a side shell and a transverse bulkhead. In this paper, two alternative structural designs of a double hull bulk carrier were carried out based on the Lloyd's rule. One has the double sided hull with longitudinal stiffeners and the other has that with a girder. The final structural design was examined in comparison with an existing single hull bulk carrier from the viewpoints of cargo hold capacity and the increases of weight and construction cost. Generally, the construction cost of a ship consists of the costs of material, labor and overhead cost. But, in this study, the relative construction cost concept was introduced to compare the economical validity more precisely. In this concept, fixed overhead cost is excluded in the assessment of construction cost, and only the variable overhead cost is added up to labor cost. As the result of this study, a double hull bulk carrier can be constructed within 1% increase of weight and construction cost.

• 한국경영과학회지
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• 제13권1호
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• pp.29-29
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• 1988

In the past decade, considerable effort has been devoted unsuccessfully to the development of information technology (IT) evaluation frameworks in the information systems area. Based on the literature review in this area and the decision analysis field, two competing evaluation frameworks are developed in this study: the direct evaluation framework and the indirect evaluation framework. A case study on Firm K shows that the latter is more practically efficient and theoretically appropriate but requires the adequate training for practitioners in order not to get confused the weight of an evaluation variable with the product of this weight and the score of the variable. Another finding is that Weill's conversion effectiveness is neither possible nor necessary to measure in the process of evaluating an IT although it is in theory an important concept.

• Communications for Statistical Applications and Methods
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• 제25권2호
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• pp.173-184
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• 2018

In medical or public health research, it is common to encounter clustered or longitudinal count data that exhibit excess zeros. For example, health care utilization data often have a multi-modal distribution with excess zeroes as well as a multilevel structure where patients are nested within physicians and hospitals. To analyze this type of data, zero-inflated count models with mixed effects have been developed where a count response variable is assumed to be distributed as a mixture of a Poisson or negative binomial and a distribution with a point mass of zeros that include random effects. However, no study has considered a situation where data are also censored due to the finite nature of the observation period or follow-up. In this paper, we present a weighted version of zero-inflated Poisson model with random effects accounting for variable individual follow-up times. We suggested two different types of weight function. The performance of the proposed model is evaluated and compared to a standard zero-inflated mixed model through simulation studies. This approach is then applied to Medicaid data analysis.

• 한국자동차공학회논문집
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• 제14권1호
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• pp.1-7
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• 2006

This paper presents an ASF (Aluminum Space Frame) BIW optimal design, which minimizes the weight and satisfies multi-disciplinary constraints such as the static stiffness, vibration characteristics, low-speed crash, high-speed crash and occupant protection. As only one cycle CPU time for all the analyses is 12 hours, the ASF design having 11-design variable is a large scaled problem. In this study, ISCD-II and conservative least square fitting method is used for efficient RSM modeling. Then, ALM method is used to solve the approximate optimization problem. The approximate optimum is sequentially added to remodel the RSM. The proposed optimization method used only 20 analyses to solve the 11-design variable design problem. Also, the optimal design can reduce the] $15\%$ of total weight while satisfying all of the multi-disciplinary design constraints.

• 대한방사선기술학회지:방사선기술과학
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• 제43권6호
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• pp.495-502
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• 2020

In this study, the prevalence of osteoporosis was predicted based on 10 independent variables such as age, weight, and alcohol consumption and 4 tree-based machine-learning models, and the performance of each model was compared. Also the model with the highest performance was used to check the performance by clearing the independent variable, and Area Under Curve(ACU) was utilized to evaluate the performance of the model. The ACU for each model was Decision tree 0.663, Random forest 0.704, GBM 0.702, and XGBoost 0.710 and the importance of the variable was shown in the order of age, weight, and family history. As a result of using XGBoost, the highest performance model and clearing independent variables, the ACU shows the best performance of 0.750 with 7 independent variables. This data suggests that this method be applied to predict osteoporosis, but also other various diseases. In addition, it is expected to be used as basic data for big data research in the health care field.

• 동아시아식생활학회지
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• 제13권6호
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• pp.577-585
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• 2003

The purpose of this study was to investigate eating behavior, nutritional status and health conditions of college students attempting a weight control. The subjects are 88 students of the Daegu area. Their weight, height, triceps, and mid-arm circumference were measured and their dietary intake and eating behavior were obtained by using questionnaires. The 24-hour recall was obtained from the subjects. The results are summarized as follows: The average height, weight and BMI of the attempt and no-attempt male and female students were 171.2cm, 70.7kg and 24.1; 170.4cm, 79.9kg and 27.5; 159.3cm, 60.9kg and 24.0; 157.7cm 60.1kg and 24.2, respectively. Energy intake of the attempt and no-attempt male and female group was 63.9%, 61.8%, 76.2% and 83.9% of RDA respectively. Protein intake of each group was 97.5%, 83.9%, 60.1% and 67.3% of RDA respectively. The following items registered a negative correlation weight and carbohydrate, weight and Na intake, weight and vitamin C intake, PIBW and Na intake, TSF and fiber intake, TSF and Na intake, TSF and vitamin C intake, MAMC and Na intake, and MAMC and vitamin C intake. A relative magnitude of factors affecting weight control was analyzed by Stepwise multiple regression analysis. Overall results about relative influence of independent variables to the dependent variable(weight control) indicated that the BMI (p<0.01) was the most significantly correlated with weight control in all subjects. The results of this study suggest that the extensive nutrition education in the weight control program should be emphasized to prevent obesity early.

• 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.

• 한국자동차공학회논문집
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• 제10권3호
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• pp.192-200
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• 2002

Semi-active suspension systems are greatly expected to be in the mainstream of future controlled suspensions for passenger cars. In this study, a continuous variable damper for a passenger car suspension is developed, which is controlled actively and exhibits high performance with light weight, low cost, and low energy consumption. To get fast response of the damper, reverse damping mechanism is adapted, and to get small pressure change rate after blow-off, a pilot controlled proportional valve is designed and analyzed. The reverse continuous variable damper is designed as a HS-SH damper that offers good body control with reduced transferred input force from tire, compared with any other type of suspension system. The damper structure is designed, so that rebound and compression damping force can be tuned independently, of which variable valve is placed externally. The rate of pressure change with respect to the flow rate after blow-off becomes smooth when the fixed orifice size increases, which means that the blow-off slope is controllable using the fixed orifice size. The damping force variance is wide and continuous, and is controlled by the spool opening, of which scheme is usually adapted in proportional valves. The reverse continuous variable damper developed in this study is expected to be utilized in the semi-active suspension systems in passenger cars after its performance and simplicity of the design is confirmed through real car test.

• 한국강구조학회 논문집
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• 제16권1호통권68호
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• pp.81-89
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• 2004

구조물과 같은 아치의 진동해석은 많은 산업분야에서 다양하게 적용되기 때문에 공학적 문제에 중요한 주제이다. 특히 변화하는 단면형상을 가지는 아치는 질량이나 강도를 최적화 하거나 특별한 구조물이나 요구조건들을 만족하기 위해서 폭넓게 사용되어 진다. 최근에는 일반화 미분구적법(GDQM)이나 미분변환법(DTM)은 각각 Shu와 Zou에 의해서 제안이 되었다. 연구에서는 변화하는 단면형상을 가지는 아치의 진동해석이 일반화 미분구적법과 미분변환법을 적용하였다. 변화하는 단면형상을 가지는 아치에 대하여 지배방정식이 유도되어졌으며, 미분변환과 일반화 미분구적법의 개념이 간단히 소개되었다. 변화하는 단면형상을 가지는 아치의 무차원화된 고유진동수가 다양한 경계조건에 대해서 구해졌으며, 이러한 방법들에 의해서 얻어지는 결과들은 선행연구와 비교 되어졌다. 일반화 미분구적법과 미분변환법은 변화하는 단면형상을 가지는 아치의 진동문제를 해석함에 있어서 빠른 수렴, 정확도, 효율성, 유효성을 보인다.