• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.4C
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• pp.316-325
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• 2002

This paper investigates the restoration schemes which are applied to the MPLS domain upon a network failure. We define the following three restoration service models by combining the various restoration schemes: "FIS-based protection service" (FIS: failure indication signal), "inversion traffic protection service" and "1+1 protection service". After a qualitative analysis of the performance in them, we have analyzed it on quantitative basis by the simulation. According to the simulation results, "1+1 protection service" guarantees the fastest and most lossless restoration service among them; however, it results in consuming considerable bandwidth and producing an amount of control traffic, which means poor network utilization. On the other hand, "FIS-based protection service" spends less bandwidth and generates less control traffic, which means better network utilization, but produces poor restoration service. "Inversion traffic protection service" provides the medium restoration service and utilization between "1+1 protection service" and "FIS-based protection service."

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.12
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• pp.210-216
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• 2013

It is hard to listen to the music clearly in the presence of background noise. In this paper, a method that modifies the audio signal automatically to enhance the audio listening experience in adverse environment is proposed. Specifically, the method that amplifies the audio signal so that the perceived loudness of audio signal in each band becomes similar to that of the noiseless signal. The loudness perception model proposed by Moore et. al is utilized. Extending the previous work that is applied to speech reinforcement, the full band signal sampled at 48kHz is manipulated based on the loudness restoration principle. Moreover, based on the observation that the audio clarity is compromised even with loudness restored signal, a modification that intentionally boosts high frequency loudness more than lower band is also proposed. Experimental results showed that the proposed algorithm can enhance the audio listening experience in adverse environment.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.10
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• pp.1859-1864
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• 2007

Existing barcode signal restoration algorithms are not robust to unmodeled outliers that may exist in scanned barcode images due to scratches, dirts, etc. In this paper, we describe a robust barcode signal restoration algorithm that uses the hybrid $L_1-L_2$ norm as a similarity measure. To optimze the similarity measure, we propose a modified iterative reweighted least squares algorithm based on the one step minimization of a quadratic surrogate function. In the simulations and experiments with barcode images, the proposed method showed better robustness than the conventional MSE based method. In addition, the proposed method converged quickly during optimization process.

• Journal of the Institute of Convergence Signal Processing
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• v.13 no.4
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• pp.187-193
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• 2012

An image authentication scheme for gray scale image through embedding a digital watermark by quantization of Integer Wavelet Transform (IWT) coefficients of the image is proposed in this paper. Proposed method is designed to detect modification of an image and to identify tampered location of the image. To embed the watermark mid-frequency band of a second level IWT was used. An approximation of the original image based on LL band was stored in LSB bits of the pixel data as a recovery mark for restoration of the image. Watermarked image has achieved a good PSNR of 40 dB compared to original cover image. Restored image quality was also very good with a PSNR of more than 35 dB compared to unmodified watermarked image even when 25% of the received image is cropped. Thus, the proposed method ensures a proper balance between the fidelity of the watermarked image and the quality of the restored image.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.203-204
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• 2008

A novel method using scaling down and restoration to reduce the PAPR of OFDM signal is proposed. This method shows a better BER performance than clipping method. And also the throughput efficiency is better than SLM.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.4
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• pp.271-280
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• 2004

This paper presents a new iterative image restoration algorithm with removal of boundary/object-oriented ringing, The proposed method is based on CGM(Conjugate Gradient Method) iterations with inter-wavelet shrinkage. The proposed method provides a fast restoration as much as CGM, while having adaptive do-noising and do-ringing by using wavelet shrinkage. In order to have effective do-noising and do-ringing simultaneously, the proposed method uses a space-dependent shrinkage rule. The improved performance of the proposed method over more traditional iterative image restoration algorithms such as LR(Lucy-Richardson) and CGM in do-noising and do-ringing is shown through numerical experiments.

• The Journal of the Acoustical Society of Korea
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• v.19 no.8
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• pp.12-21
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• 2000

In this paper, we propose a novel hearing aid algorithm for sensorinural hearing loss restoration with multi-channel(band) dynamic range compression and psychoacoustics. In this way, we can present a normal perception condition to the impaired listener. The proposed algorithm make loudness scaling function achieve proper loudness level, and analysis masking property for the signal will be perceived to impaired listener, and then, restore normal spectral contrast using SMR(signal-to-masking ratio) defined by distance between the level of each frequency and masking threshold.

• Communications for Statistical Applications and Methods
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• v.29 no.1
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• pp.27-40
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• 2022

In this paper, the focus on the removal noise in the binary image based on the variational Bayesian method with the Ising model. The observation and the latent variable are the degraded image and the original image, respectively. The posterior distribution is built using the Markov random field and the Ising model. Estimating the posterior distribution is the same as reconstructing a degraded image. MCMC and variational Bayesian inference are two methods for estimating the posterior distribution. However, for the sake of computing efficiency, we adapt the variational technique. When the image is restored, the iterative method is used to solve the recursive problem. Since there are three model parameters in this paper, restoration is implemented using the VECM algorithm to find appropriate parameters in the current state. Finally, the restoration results are shown which have maximum peak signal-to-noise ratio (PSNR) and evidence lower bound (ELBO).

• The KIPS Transactions:PartC
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• v.10C no.5
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• pp.603-610
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• 2003

On the optical network, it is important to build restoration scheme capable to network survivability in preparation of potential failure on communication route. This paper analyze the existing schemes on restoration of failure on the optical network, and propose deferred commit scheme to improve resource utilization and management efficiency. Also, the transfer flow of messages needed for transferring restoration signal are presented in a concrete way and delay time required by shared mesh restoration scheme is explained in a substantial way. Simulation-based comparative analysis of various schemes is performed.

• Journal of the Institute of Convergence Signal Processing
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• v.6 no.3
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• pp.112-119
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• 2005

In this paper, a model of neural circuit was proposed, which abstracts the depth information in two images gotten from right and left retinas. The proposed neural circuit corresponds to binocular stereo vision based on psychologic and physiological knowledge, and we examine a restoration method of three-dimensional surface. In case of drawing a disparity based on characteristics of images, we can not abstract the depth information correctly if resemblant characteristics are repeated on the boundary region of an object. A binocular disparity is decided in a model of neural circuit by abstraction, synthesis, and correction of a disparity. And we propose a method which restores three-dimensional shape by correcting a depth information, and also restores a three-dimensional surface by mapping a left input image on the restored three-dimensional shape. And we confirmed that the computation time for disparity abstraction can be greatly reduced through the simulation.