• Proceedings of the Korean Statistical Society Conference
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• 2003.10a
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• pp.331-334
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• 2003

마이크로 어레이(microarray)실험에서 표준화(normalization)는 유전자의 발현수준에 영향을 미치는 여러 기술적인 변인을 제거하는 과정이다. cDNA microarray normalization에 있어 여러 방법이 제안되었지만, 이중 print-tip 효과가 존재할 때 사용되는 방법으로 print-tip lowess normalization이 대표적으로 사용된다. normalization에 사용되는 lowess 함수는 데이터의 특성에 따라 window width를 정해야만 연구의 목적에 맞는 결과를 도출할 수 있다. 본 논문에서는 각각의 tip에서 최적의 window width를 계산하는 절차를 논의하였다. 또한 이의 결과와 기존의 같은 window width를 사용하는 print-tip lowess normalization 결과와 비교 평가하여 normalization의 기본 원칙에 대한 타당성을 확인하였다.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.51 no.6
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• pp.267-271
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• 2002

The Hotelling transform is based on statistical properties of an image. The principal uses of this transform are in data compression. The basic concept of the Hotelling transform is that the choice of basis vectors pointing the direction of maximum variance of the data. This property can be used for rotation normalization. Many objects of interest in pattern recognition applications can be easily standardized by performing a rotation normalization that aligns the coordinate axes with the axes of maximum variance of the pixels in the object. However, this transform can not be used to rotation normalization of color images directly. In this paper, we propose a new method for rotation normalization of color images based on the Hotelling transform. The Hotelling transform is performed to calculate basis vectors of each channel. Then the summation of vectors of all channels are processed. Rotation normalization is performed using the result of summation of vectors. Experimental results showed the proposed method can be used for rotation normalization of color images effectively.

• Molecules and Cells
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• v.22 no.3
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• pp.254-261
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• 2006

DNA microarray is a powerful tool for high-throughput analysis of biological systems. Various computational tools have been created to facilitate the analysis of the large volume of data produced in DNA microarray experiments. Normalization is a critical step for obtaining data that are reliable and usable for subsequent analysis such as identification of differentially expressed genes and clustering. A variety of normalization methods have been proposed over the past few years, but no methods are still perfect. Various assumptions are often taken in the process of normalization. Therefore, the knowledge of underlying assumption and principle of normalization would be helpful for the correct analysis of microarray data. We present a review of normalization techniques from single-labeled platforms such as the Affymetrix GeneChip array to dual-labeled platforms like spotted array focusing on their principles and assumptions.

• Journal of the Korea Society of Computer and Information
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• v.20 no.1
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• pp.21-28
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• 2015

Feature normalization as a pre-processing step has been widely used to reduce the effect of different scale in each feature dimension and error rate in classification. Most of the existing normalization methods, however, do not use the class labels of data points and, as a result, do not guarantee the optimality of normalization in classification aspect. A supervised rank normalization method, combination of rank normalization and supervised learning technique, was proposed and demonstrated better result than others. In this paper, another technique, training sample selection, is introduced in supervised feature normalization to reduce classification error more. Training sample selection is a common technique for increasing classification accuracy by removing noisy samples and can be applied in supervised normalization method. Two sample selection measures based on the classes of neighboring samples and the distance to neighboring samples were proposed and both of them showed better results than previous supervised rank normalization method.

• Journal of the Korean Statistical Society
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• v.23 no.2
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• pp.341-348
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• 1994

Some extensions of the law of the iterated logarithm via self-normalization are obtained for seuences of sign-invariant random variables.

• Speech Sciences
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• v.11 no.1
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• pp.31-42
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• 2004

This paper presents methods using Gaussian normalization for converting pitch contours based on prosodic phrases along with experimental tests on the Korean database of 16 declarative sentences and the first sentences of the story of 'The Three Little Pigs'. We propose a new conversion method using Gaussian normalization to the pitch deviation of pitch contour subtracted by partial declination lines: by using partial declination lines for each accentual phrase of pitch contour, we avoid the problem that a Gaussian normalization using average values and standard deviations of intonational phrase tends to lose individual local variability and thus cannot modify individual characteristics of pitch contour from a source speaker to a target speaker. From the results of the experiments, we show that this slanted Gaussian normalization using these declination lines subtracted from pitch contour of accentual phrases can modify pitch contour more accurately than other methods using Gaussian normalization.

• Journal of Korean Institute of Industrial Engineers
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• v.40 no.1
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• pp.140-150
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• 2014

University ranking models, though they consider multiple indicators to evaluate universities, determine the overall score of each university based on their own normalization and aggregation methods. Thus, the rankings provided by such models primarily depend on actual scores of evaluation indicators, but they are also significantly affected by the normalization and aggregation methods. We examine the normalization methods of four university ranking models used in South Korea, China, and United Kingdom. We discuss a possible unintended consequence of these methods, i.e., some universities who want to improve their rankings may focus on unnecessary indicators, contrary to the evaluator's intension, due to the normalization methods. We suggest a new normalization method based on the statistical characteristics of the distribution of each evaluation indicator so that the new method can motivate the universities to move into the desirable directions intended by the evaluator.

• Journal of Internet Computing and Services
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• v.4 no.3
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• pp.9-14
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• 2003

The method of vocal tract normalization is a successful method for improving the accuracy of inter-speaker normalization. In this paper, we present an intra-speaker warping factor estimation based on pitch alteration utterance. The feature space distributions of untransformed speech from the pitch alteration utterance of intra-speaker would vary due to the acoustic differences of speech produced by glottis and vocal tract. The variation of utterance is two types: frequency and amplitude variation. The vocal tract normalization is frequency normalization among inter-speaker normalization methods. Therefore, we have to consider amplitude variation, and it may be possible to determine the amplitude warping factor by calculating the inverse ratio of input to reference pitch. k, the recognition results, the error rate is reduced from 0.4% to 2.3% for digit and word decoding.

• Journal of KIISE:Databases
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• v.33 no.5
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• pp.486-494
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• 2006

A web page can be represented by syntactically different URLs. URL normalization is a process of transforming URL strings into canonical form. Through this process, duplicate URL representations for a web page can be reduced significantly. A number of normalization methods have been heuristically developed and used, and there has been no study on analyzing the normalization methods systematically. In this paper, we give a way to evaluate normalization methods in terms of efficiency and effectiveness of web applications, and give users guidelines for selecting appropriate methods. To this end, we examine all the effects that can take place when a normalization method is adopted to web applications, and describe seven metrics for evaluating normalization methods. Lastly, the evaluation results on 12 normalization methods with the 25 million actual URLs are reported.

• Phonetics and Speech Sciences
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• v.12 no.3
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• pp.65-71
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• 2020

Feature normalization is a method to reduce the effect of environmental mismatch between the training and test conditions through the normalization of statistical characteristics of acoustic feature parameters. It demonstrates excellent performance improvement in the traditional Gaussian mixture model-hidden Markov model (GMM-HMM)-based speech recognition system. However, in a deep neural network (DNN)-based speech recognition system, minimizing the effects of environmental mismatch does not necessarily lead to the best performance improvement. In this paper, we attribute the cause of this phenomenon to information loss due to excessive feature normalization. We investigate whether there is a feature normalization method that maximizes the speech recognition performance by properly reducing the impact of environmental mismatch, while preserving useful information for training acoustic models. To this end, we introduce the mean and exponentiated variance normalization (MEVN), which is a compromise between the mean normalization (MN) and the mean and variance normalization (MVN), and compare the performance of DNN-based speech recognition system in noisy and reverberant environments according to the degree of variance normalization. Experimental results reveal that a slight performance improvement is obtained with the MEVN over the MN and the MVN, depending on the degree of variance normalization.