• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.7
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• pp.26-32
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• 1994

The Lloyd-Max algorithm is an iterative scheme for design of the minimum mean square error quantizer. It is very simple in concept and easy to program into a computer. However its convergence and accuracy are primarily dependent upon the accuracy of the initial parameter. In this paper, a new initial parameter which converges to a specific value when the number of output levels becomes large is selected. And an estimator using curve fitting techique is suggested. In addition, performance of the proposed method is shown to be superior to that of the existing methods in accuracy and convergence.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.07a
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• pp.394-395
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• 2010

본 논문은 최소 평균 제곱 오차(minimum mean-square error: MMSE)에 기반한 비국소적 (nonlocal) 평균 영상 잡음 제거기법을 제안한다. 제안하는 기법에서는 기존의 비국소적 평균 기법에 추정 이론을 적용하여 잡음 제거에 사용되는 이웃 블록 또한 잡음을 포함하는 일반적인 경우로 확장하여 이웃 블록에 인가되는 가중치를 적응적으로 조절한다. 컴퓨터 모의실험을 통해 제안하는 알고리듬이 기존의 비국소적 기법에 비해 잡음 제거 성능이 향상됨을 확인한다.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.191-192
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• 2008

We give new definition of the effective-leakage and the signal to effective-leakage plus noise ratio (SELNR) to consider receiver combining motivated by the leakage. We propose a method to find jointly beamforming vector and combining vector for the two linear receivers (maximal ratio combining (MRC) receiver and minimum mean square error (MMSE) receiver) based on the SELNR.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.281-282
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• 2008

Turbo equalizers which use MAP (maximum a posteriori probability) equalizer or MMSE (minimum mean square error) equalizer have shown high performance and adoptability [1], [2]. In this paper, we show that the BP (belief propagation) algorithm can also be applied in equalizer and when it is connected with channel code, it can replace the MAP equalizer with similar complexity and performance.

• Proceedings of the IEEK Conference
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• 2003.07e
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• pp.2188-2191
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• 2003

이 논문에서는 라플라스 밀도함수에 대한 최적 홑양자기 지지역은 양자점의 개수와 로그선형 관계가 있음을 증명한다. 그리고, 극상한값을 유도하여 최적 지지역의 로그선형 증가가 어떤 상수값을 초과하지 않음을 증명한다. 이 결과들로부터, 학계에 경험적으로 알려져 왔던 최적 지지역의 로그선형 증가를 증명한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.8
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• pp.2722-2742
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• 2014

We propose methods of linear transceiver design for two different power constraints, sum relay power constraint and per relay power constraint, which determine signal processing matrices such as base station (BS) transmitter, relay precoders and user receivers to minimize sum mean square error (SMSE) for multi-relay multi-user (MRMU) networks. However, since the formulated problem is non-convex one which is hard to be solved, we suboptimally solve the problems by defining convex subproblems with some fixed variables. We adopt iterative sequential designs of which each iteration stage corresponds to each subproblem. Karush-Kuhn-Tucker (KKT) theorem and SMSE duality are employed as specific methods to solve subproblems. The numerical results verify that the proposed methods provide comparable performance to that of a full relay cooperation bound (FRCB) method while outperforming the simple amplify-and-forward (SAF) and minimum mean square error (MMSE) relaying in terms of not only SMSE, but also the sum rate.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.1
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• pp.128-132
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• 1996

In [1], it is shown that a subclass of ETBFs, which are self-dual ETBFs, can be expressed as a weighted average of median subfiltered outputs. In this paper, we extend this result to general ETBFs. In particular, we show that any ETBF can be represented as a weighted average of minimum (or maximum) subfiltered outputs. These representations naturally lead to a subclass of ETBF, called the K-th order ETBF (K-ETBF) that employs only those subfilters whose window sizes are less than or equal to K. By designing K-ETBFs under the mean square error criterion for various values of K and applying them to restore noisy signals, the tradeoff between the performance and the complexity of this class of filters is examined.

• Advances in materials Research
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• v.11 no.1
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• pp.75-90
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• 2022

In this paper, functionality of soft computing algorithms such as Group method of data handling (GMDH), Random forest (RF), Random tree (RT), Linear regression (LR), M5P, and artificial neural network (ANN) have been looked out to predict the compressive strength of concrete mixed with marble powder. Assessment of result suggests that, the overall performance of ANN based model gives preferable results over the different applied algorithms for the estimate of compressive strength of concrete. The results of coefficient of correlation were maximum in ANN model (0.9139) accompanied through RT with coefficient of correlation (CC) value 0.8241 and minimum root mean square error (RMSE) value of ANN (4.5611) followed by RT with RMSE (5.4246). Similarly, other evaluating parameters like, Willmott's index and Nash-sutcliffe coefficient value of ANN was 0.9458 and 0.7502 followed by RT model (0.8763 and 0.6628). The end result showed that, for both subsets i.e., training and testing subset, ANN has the potential to estimate the compressive strength of concrete. Also, the results of sensitivity suggest that the water-cement ratio has a massive impact in estimating the compressive strength of concrete with marble powder with ANN based model in evaluation with the different parameters for this data set.

• Journal of Korea Society of Digital Industry and Information Management
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• v.7 no.2
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• pp.1-8
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• 2011

In this study, software products developed in the course of testing, software managers in the process of testing software test and test tools for effective learning effects perspective has been studied using the NHPP software. The finite failure non-homogeneous Poisson process models presented and the life distribution applied extreme distribution which used to find the minimum (or the maximum) of a number of samples of various distributions. Software error detection techniques known in advance, but influencing factors for considering the errors found automatically and learning factors, by prior experience, to find precisely the error factor setting up the testing manager are presented comparing the problem. As a result, the learning factor is greater than automatic error that is generally efficient model could be confirmed. This paper, a numerical example of applying using time between failures and parameter estimation using maximum likelihood estimation method, after the efficiency of the data through trend analysis model selection were efficient using the mean square error.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.8A
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• pp.813-819
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• 2007

In this paper, the effect of a propagation delay resulting from the use of an OFDM-based cellular system with a transparent mobile multi-hop relay(MMR) is initially analyzed. Then, channel estimation techniques, a least square(LS) method and a minimum mean square error(MMSE) method, for the OFDM systems with throughput enhancement(TE) MMR or cooperative MMR are proposed. The proposed channel estimation techniques can overcome the performance degradation caused by the propagation delay in TE MMR or cooperative MMR systems. It is demonstrated by computer simulation that the proposed channel estimation techniques for OFDM systems with transparent MMR are superior to the conventional techniques in terms of mean square error(MSE) and bit error rate(BER).