• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.618-622
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• 2008

In this paper, we suggest new music composition algorithm based on fractal theory. User can define and control fractal shape by setting an initial state and production rules in L-System. We generate an asymmetric fractal tree based on L-System and probability. Then a music is generated by the fractal tree image using sonification techniques. We introduce two composition algorithm using the fractal tree. First, monophonic music can be generated by mapping x and y axis to velocity and pitch, respectively Second, harmonic music also can be generated by mapping x and y axis to time and pitch, respectively Using our composition algorithm, user can easily generate a music which has repeated pattern created by recursive feature of fractal, and a music which has structure similar to fractal tree image.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.39 no.3
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• pp.35-41
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• 2002

There are many image segmentation methods having been published as the results of research so far, but it is difficult to be partitioned to each similar range that should be extracted into the accurate parameters of image information on the images with noises. Also if it is used to fractal coding, according to amount of noise in image, the image segmentation leads to decreasing of the compression ratio. In this paper, we propose the new quad-tree image segmentation using the box-counting dimension which can estimate the effective image information parameters against the noise properties and apply this method to fractal image coding. As the result of simulation, we confirm that the image segmentation is improved to 31.10% for parameter detection of image information and compression ratio is enhanced to 38.93% for fractal image coding when tested on 10% Gaussian white noise image by the proposed quad-tree method compared with method using existing quad-tree. 

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.11 no.6
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• pp.50-56
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• 1997

As the purpose of the breakdown prediction of three degradation of insulating materials caused by partial discharge occurring at various defects in the polymer insulator itself and at the interfaces between electrodes and the insulating materials. Treeing due to partial discharge os one of the main causes of breakdown of the insulating materials. Recently, the necessity of establishing the way to diagnoses the aging of insulation materials and to predict of insulation breakdown become improtant. The purpose of our work are to use acoustic emission System and fractal dimension and to investigated the treeing phenomena in polymeric insulation under appliec AC voltage 11[kV] with an artificial needleshaped void(1.5[mm]) using the above system.

• Journal of Broadcast Engineering
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• v.4 no.2
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• pp.127-133
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• 1999

The conventional fractal image compression based on discrete wavelet transform uses the fixed block size in fractal coding and reduces PSNR at low bit rate. This paper proposes a fractal image coding based on discrete wavelet transform which improves PSNR by using variable block size in fractal coding. In the proposed method. the absolute values of discrete wavelet transform coefficients are computed. and the discrete wavelet transform coefficients of different highpass subbands corresponding to the same spatial block are assembled. and the fractal code for the range block of each range block level is assigned. and then a decision tree C. the set of choices among fractal coding. "0" encoding. and scalar quantization is generated and a set of scalar quantizers q is chosen. And then the wavelet coefficients. fractal codes. and the choice items in the decision tree are entropy coded by using an adaptive arithmetic coder. This proposed method improved PSNR at low bit rate and could achieve a blockless reconstructed image. As the results of experiment. the proposed method obtained better PSNR and higher compression ratio than the conventional fractal coding method and wavelet transform coding.rm coding.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1996.06a
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• pp.187-190
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• 1996

본 논문은 고속의 프랙탈 영상압축 기법으로 알려져 있는 Bath 프랙탈 영상 압축 기법의 성능을 여러 가지 측면에서 분석한다. Bath 프랙탈 영상 압축 기법은 영상의 빠른 복호화가 가능하므로 미래의 다양한 형태로 요구되는 정보서비스, VOD(Video On Demand), CD-ROM 등과 같이 저장되어 있는 영상 정보의 빠른 복원이 요구되는 곳에 적합한 부호화 기술이므로 그 성능에 대한 분석이 중요하다. 본 논문에서는 Bath 프랙탈 압축 기법의 양자화 방법에 따른 성능 분석, 프랙탈 계수 값의 분포에 따른 성능 평가, 사용된 어핀 맵핑식에 따른 성능 비교, 영상내의 에지 빈도수에 따른 성능 변화, 쿼드트리 구조의 작은 블록들에 대한 BFT의 성능 평가 등을 고찰한다.

• Journal of Biomedical Engineering Research
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• v.21 no.3 s.61
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• pp.247-254
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• 2000

We propose an efficient MR image compression technique using fractal coding in wavelet transform domain. In the Proposed method , we construct significant coefficient trees with the absolute values of discrete wavelet transform coefficients and then perform the fractal coding with the information of significant coefficients having high energy. For MR images, most Pixels including background have very low gray level values, the number of significant coefficients is small. so we can expect high compression rate. In addition. since this method uses the fractal coding in wavelet transform domain, blocking artifact is reduced prominently and edges sensitive to human visual system are well preserved. As a result of computer simulation, we obtained the reconstructed images with better quality than those by JPEG at the low bit rates below 0.33[bpp].

• The Transactions of the Korea Information Processing Society
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• v.5 no.4
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• pp.1048-1056
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• 1998

In this paper, a fractal image coding based on discrete wavelet transform is proposed to improve PSNR at low bit rates and reduce computational complexity of encoding process. The proposed method takes the absolute value of discrete wavelet transform coefficients, and then constructs significant coefficients trees, which indicate the positions and signs of the significant coefficients. This method improves PSNR and reduces computational complexity of mapping contracted domain pool onto range block, by matching only the significant coefficients of range block to coefficients of contracted domain block. Also, this paper proposes a classification scheme which minimizes the number of contracted domain blocks compared with range block. This scheme significantly reduces the number of range and contracted domain block comparison.

• Journal of the Korean Society of Radiology
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• v.8 no.1
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• pp.19-26
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• 2014

This paper suggests techniques to enhance coding time which is a problem in traditional fractal compression and to improve fidelity of reconstructed images by determining fractal coefficient through adaptive selection of block approximation formula. First, to reduce coding time, we construct a linear list of domain blocks of which characteristics is given by their luminance and variance and then we control block searching time according to the first permissible threshold value. Next, when employing three-level block partition, if a range block of minimum partition level cannot find a domain block which has a satisfying approximation error, we choose new approximation coefficients using a non-linear approximation of luminance term. This boosts the fidelity. Our experiment employing the above methods shows enhancement in the coding time more than two times over traditional coding methods and shows improvement in PSNR value by about 1-3dB at the same compression rate.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.35T no.3
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• pp.15-24
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• 1998

In this paper, we present new method of fractal image coding based on iterated function system(IFS) suggested by Barnsley. In previous Fractal coding using full searching algorithm, the quality of reconstructed image was better than other fractal coding method's, but it took a long time in that algorithm for searching domain blocks matched. And it is performed through linear affine transform, therefore it is difficult to approximate the complex range blocks. In this paper, using quadtree partitioning, complex blocks are divided into more smaller blocks, and simple blocks are merged to more larger blocks. So, we can got more precisely approximated range blocks and reduce the number of transformations. Hence, we have improved the compression ratio. In addition, we restrict the region of searching domains in order to reduce the searching time and coding time. Compared with full searching algorithm, we reduced coding time drastically, and quality of reconstructed image was better in terms subjective criteria. And compared with Monro's, our method is slower, but we could obtain a reconstructed image with better quality.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1588-1590
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• 1996

The fractal characteristics of AC electrical tree grown in DGEBA/MDA/ SN/HQ system was investigated. As the applied voltage decreased, tree initiated after retardation. All the trees were fractals in spite of tile applied voltage. Fractal dimension increased with tree length. When the tree grew slowly, the fractal dimension or tile degree of treeing deterioration increased.