• Communications for Statistical Applications and Methods
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• v.20 no.5
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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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• v.22 no.2
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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.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.4
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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.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.10 no.1
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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.

• School Mathematics
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• v.10 no.3
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• pp.319-337
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• 2008

Intuitions in independence formed by common language help and also hinder the establishment of new conceptual system about independence as a mathematical term. Intuitions which entail such conflicts can be a driving force in explaining independence but at the same time, it is the impedimental factor causing a misconception. The goal of this paper is to help students use the intuitions properly by distinguishing helpful intuitions and impedimental intuitions. This paper suggests that we need to reveal in teaching the misconception resulting not from mathematic but from linguistic interpretation of independence. This paper points out the need for the clear distinction of independence of trials and independence of events and gives an counterexample of the case that sampling with and without replacement shouldn't be specified as a representative example of independence and dependence of events. The analysis of intuition in this parer is based on intuitions classified by Fischbein and this paper analyzed institutions applied to the concept of independence corresponding intuitions classified by Fischbein.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.7
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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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• v.8 no.1
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• pp.42-49
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• 2004

Purpose : The quantization noise in magnetic resonance imaging (MRI) systems is analyzed. The signal-to-quantization noise ratio (SQNR) in the reconstructed image is derived from the level of quantization in the signal in spatial frequency domain. Based on the derived formula, the SQNRs in various main magnetic fields with different receiver systems are evaluated. From the evaluation, the quantization noise could be a major noise source determining overall system signal-to-noise ratio (SNR) in high field MRI system. A few methods to reduce the quantization noise are suggested. Materials and methods : In Fourier imaging methods, spin density distribution is encoded by phase and frequency encoding gradients in such a way that it becomes a distribution in the spatial frequency domain. Thus the quantization noise in the spatial frequency domain is expressed in terms of the SQNR in the reconstructed image. The validity of the derived formula is confirmed by experiments and computer simulation. Results : Using the derived formula, the SQNRs in various main magnetic fields with various receiver systems are evaluated. Since the quantization noise is proportional to the signal amplitude, yet it cannot be reduced by simple signal averaging, it could be a serious problem in high field imaging. In many receiver systems employing analog-to-digital converters (ADC) of 16 bits/sample, the quantization noise could be a major noise source limiting overall system SNR, especially in a high field imaging. Conclusion : The field strength of MRI system keeps going higher for functional imaging and spectroscopy. In high field MRI system, signal amplitude becomes larger with more susceptibility effect and wider spectral separation. Since the quantization noise is proportional to the signal amplitude, if the conversion bits of the ADCs in the receiver system are not large enough, the increase of signal amplitude may not be fully utilized for the SNR enhancement due to the increase of the quantization noise. Evaluation of the SQNR for various systems using the formula shows that the quantization noise could be a major noise source limiting overall system SNR, especially in three dimensional imaging in a high field imaging. Oversampling and off-center sampling would be an alternative solution to reduce the quantization noise without replacement of the receiver system.