• Communications for Statistical Applications and Methods
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• 제20권5호
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• pp.357-366
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• 2013

This paper defines an improvement for estimating the population mean of a study variable using auxiliary information and known values of certain population parameter(s), when there is a non-response in a study as well as on auxiliary variables. Under a simple random sampling without a replacement (SRSWOR) scheme, the mean square error (MSE) of all proposed estimators are obtained and compared with each other. Numerical illustration is also given.

• Communications for Statistical Applications and Methods
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• 제22권2호
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• pp.137-146
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• 2015

Singh (2013) considered the dual problem to the calibration of design weights to obtain a new generalized linear regression estimator (GREG) for the finite population total. In this work, we have made an attempt to suggest a way to use the dual calibration of the design weights in case of multi-auxiliary variables; in other words, we have made an attempt to give an answer to the concern in Remark 2 of Singh (2013) work. The same idea is also used to generalize the GREG estimator proposed by Deville and S$\ddot{a}$rndal (1992). It is not an easy task to find the optimum values of the parameters appear in our approach; therefore, few suggestions are mentioned to select values for such parameters based on a random sample. Based on real data set and under simple random sampling without replacement design, our approach is compared with other approaches mentioned in this paper and for different sample sizes. Simulation results show that all estimators have negligible relative bias, and the multivariate case of Singh (2013) estimator is more efficient than other estimators.

• 한국자동차공학회논문집
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• 제6권4호
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• pp.76-85
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• 1998

Recently, Genetic Algorithm(GA) is widely adopted into a search procedure for structural optimization, which is a stochastic direct search strategy that mimics the process of genetic evolution. This methods consist of three genetics operations maned selection, crossover and mutation. Contrast to traditional optimal design techniques which use design sensitivity analysis results, GA, being zero-order method, is very simple. So, they can be easily applicable to wide area of design optimization problems. Also, owing to multi-point search procedure, they have higher probability of converge to global optimum compared to traditional techniques which take one-point search method. In this study, a method of finding the optimum values of suspension parameters is proposed by using the GA. And vehicle is modelled as planar vehicle having 5 degree-of-freedom. The generalized coordinates are vertical motion of passenger seat, sprung mass and front and rear unsprung mass and rotate(pitch) motion of sprung mass. For rapid converge and precluding local optimum, share function which distribute chromosomes over design bound is introduced. Elitist survival model, remainder stochastic sampling without replacement method, multi-point crossover method are adopted. In the sight of the improvement of ride comfort, good result can be obtained in 5-D.O.F. vehicle model by using GA.

• 대한유전성대사질환학회지
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• 제10권1호
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• pp.59-66
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• 2010

Enzyme replacement of therapy (ERT) is one of the most promising therapeutic strategies for the treatment of lysosomal storage disorders. ERT is available in three types of Mucopolysaccharidosis (MPS): for MPS I (Aludrazyme$^{(R)}$), MPS II (Elaprase$^{(R)}$) and MPS VI (Naglazyme$^{(R)}$) patients who are over 5 years old. But recently, early diagnosis can be done by expert clinicians and even in prenatal case. We describe the case of ERT under 5 years old MPS patients. Up to June, 2010 in Samsung Medical Center, there are 6patients who were diagnosed as MPS and started ERT under 5 years old. 3 patients were MPS I, 3 patients were MPS II. 2 patient who was diagnosed as MPS I was female and others were male. Their age at diagnosis were 4 to 37month-old (4, 13, 16, 25, 27, 37 month-old) and they are now 9 to 60 month-old (9, 39, 32, 81, 60 month-old). The youngest patient was started ERT at 4 month-old and others were started at their 13 to 49 month-old (13, 29, 27, 28, 49 month-old). First manifested symptoms of patients were macrocephaly, kyphosis and coarse face appearance. Especially, in 2 of them, one was MPS I and the other was MPS II had elder brother with same disease. And the youngest one was diagnosed by the iduronate-2-sulfatase (IDS) gene analysis from chorionic villi sampling. His mother knew that she was a heterozygous carrier of IDS gene mutation because her younger brother died from MPS II. All of them confirmed as MPS by the enzyme assay in leukocytes and fibroblast skin culture. We started ERT with ${\alpha}$-L-iduronidase(Aldurazyme$^{(R)}$) to MPS I and did recombinant human iduronate-2-sulfatase (Elaprase$^{(R)}$) to MPS II patients as recommended dose as over 5 years old. But for MPS II patient who was 4 month old, we started ERT by recombinant human IDS (Elaprase$^{(R)}$) with reduced dose 0.1 mg/kg and increased dose every 2 weeks by 0.1mg/kg up to 0.5mg/kg IV infusion. During ERT, all patients had no adverse effects and the excretion of GAGs were decreased. We have evaluated other clinical symptoms such as liver/ spleen volume, heart function and neurologic evaluation. We describe a successful ERT to MPS I and MPS II patient under 5 years old without any adverse event. It indicates that ERT in young children are well tolerated and that it has several effects which may confer clinical benefits with long-term therapy.

• 대한수학교육학회지:학교수학
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• 제10권3호
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• pp.319-337
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• 2008

일상어로서의 언어적 개념에 의해 형성된 독립에 대한 직관은 수학에서의 독립성에 대한 새로운 개념체계를 확립하는 데 있어 도움을 주거나 방해를 한다. 다시 말해 이러한 갈등을 동반하는 직관은 독립성을 설명을 설명하는데 원동력이 되기도 하나 때로는 오개념을 유발하는 장애요인이기도 하다. 본 논문의 목적은 이러한 원동력이 되는 직관과 장애가 되는 직관을 구분하여 학생들이 직관을 바르게 사용하도록 하는 데 있다. 이로써 독립의 언어적 해석의 개입으로 인해 발생하는 잘못된 직관에 의한 오개념을 오히려 드러내어 가르칠 필요가 있음을 제안하였다. 또한 시행의 독립성과 사건의 독립성의 명확한 구분이 필요하다는 것을 제안하였으며, 복원추출과 비복원 추출이 사건의 독립과 종속의 대표적인 예로 특정화되어서는 안 되는 것을 반례를 통해 보였다. 본 논문에서의 직관의 분석은 Fischbein이 분류한 직관을 바탕으로 하였으며 독립성의 개념에 적용되는 직관을 구체적으로 Fischbein의 직관과 대응시켜 분석하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제17권7호
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• pp.960-966
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• 2004

The purpose of this study was to evaluate the effects of protein supplementation of green tea waste (GTW) on the performance of lactating cows. Another aim was to increase resource utilization and to eliminate any environmental negative impact from the tea waste. GTW from a beverage company was ensiled at a low pH (<4.0) and high acetic acid and lactic acid concentration, and it contained high crude protein (CP, 34.8%), total extractable tannins (TET, 9.2%) and condensed tannin (CT, 1.7%). Two experiments were conducted to investigate the palatability and performance in lactating cows fed GTW. In the palatability trial, three lactating cows were allocated to three dietary treatments in a 3$\times$3 Latin square design. The animals were offered a total mixed ration (TMR) including GTW at rates of 0, 2.5 and 5.0% on a dry matter (DM) basis. Total DM intake was not different among the treatments. In the performance trial, four lactating cows were used in a 2$\times$2 Latin square design with a 3 week sampling period. GTW was incorporated into TMR at a rate of 5.0% on a DM and 10.0% on a CP basis. Thus GTW replaced alfalfa hay and soybean meal at a level of 25.0% on a DM. DM and CP intake were not affected by the inclusion of GTW, whereas TET and CT intake were significantly increased (p<0.001). Milk production, milk composition and the efficiency of milk production were not altered by the GTW inclusion. Although ruminal pH and VFA, and blood urea nitrogen were not changed, ruminal $NH_{3}-N$ and plasma total cholesterol were relatively low in the GTW group, but not significantly different. The excretion of urinary purine derivatives and estimated MN supply were also not significantly affected by GTW treatment. It is therefore concluded that GTW can be used as a protein source without any detrimental effects on the performance of lactating cows.

• Investigative Magnetic Resonance Imaging
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• 제8권1호
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• pp.42-49
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• 2004

목적 : 자기공명영상시스템에서 양자화잡음을 분석하였다. 신호대양자화잡음비를 이론적으로 유도하였고 다양한 자기공명영상시스템에서 신호대양자화잡음비를 계산하였다. 이러한 계산으로부터 고자장영상시스템에서는 양자화잡음이 전체시스템의 신호대잡음비를 결정짓는 주된 잡음원이 될 수 있음을 보였다. 하드웨어의 교체없이 양자화잡음을 줄일 수 있는 방법들을 제시하였다. 대상 및 방법 : 자기공명영상에서 사용되는 Fourier 영상기법에서는 위상 및 주파수 인코딩 방법으로 자기공명신호를 공간주파수 형태의 신호로 변환하여 측정하게 된다. 따라서 공간주파수 영역에서 발생하는 양자화잡음을 재구성된 영상에서의 신호대양자화잡음비로 나타내었다. 컴퓨터 시뮬레이션 및 실험을 통하여 유도된 식의 타당성을 보였다. 결과 : 유도된 식을 이용하여 다양한 주 자장 및 수신 시스템에 대하여 신호대양자잡음비를 계산하였다. 양자화잡음은 신호의 크기에 비례하여 증가하므로 상대적으로 신호가 큰 고자장 시스템에서 보다 큰 문제점으로 부각될 수 있다. 많은 수신 시스템에서 채택하고 있는 16 bits/샘플 양자기로는 양자화 잡음이 고자장 시스템에서 기대되는 신호대잡음비의 향상을 제한할 수 있는 주된 잡음원이 될 수 있음을 보였다. 결론 : fMRI나 spectroscopy를 위하여 자기공명영상의 주 자장은 지속적으로 높아지고 있다. 고자장에서는 신호가 커지고, susceptibility와 스펙트럼의 분리가 커져서 fMRI 나 spectroscopy에 유리한 면이 많다. 양자화잡음은 신호의 크기에 비례하여 증가하기 때문에 만약 양자기의 변환 비트가 충분히 크지 않을 경우 양자화잡음이 커져 신호의 증가에 비례하는 신호대잡음비의 향상을 이룰 수 없다. 이 논문에서는 신호대양자화잡음비를 이론적으로 유도하고, 다양한 자장의 세기 및 수신 시스템에 대하여 신호대양자화잡음비를 계산함으로써 고자장에서, 특히 상대적으로 신호가 큰 3차원영상에서 , 양자화잡음이 전체 시스템의 신호대잡음비를 제한할 수 있는 주된 잡음원이 될 수 있음을 보였다. 근원적인 해결책은 아닐 수 있으나 oversampling과 에코의 센터를 비껴가는 샘플링으로 하드웨어의 향상없이 양자화잡음을 줄일 수 있는 방법을 제시하였다.