• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.8C
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• pp.790-800
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• 2009

For the improvement of coding efficiency, the H.264/AYC standard uses new coding tools such as 1/4-pel-accurate motion estimation, multiple references, intra prediction, loop filter, variable block size etc. Using these coding tools, H.264/AYC has achieved significant improvements from rate-distortion point of view compared to existing standards. However, the encoder complexity was greatly increased due to these coding tools. We focus on the complexity reduction method of intra macroblock mode selection. The proposed algorithm for fast intra mode selection calculates the edge activity in transform domain, and performs fast encoding of intra frame in H.264/AYC through the fast prediction mode selection of intra4x4 and chrominance blocks. Simulation results show that the proposed method saves about 59.76% for QCIF sequences and 65.03% for CIF sequences of total encoding time, while bitrate increase and PSNR decrease are very small.

• Journal of Chest Surgery
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• v.16 no.2
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• pp.157-163
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• 1983

Ebstein's anomaly is a rare congenital cardiac malformation oand the ideal surgical correction seems controversial at present, and some problems are left unsolved in the surgical correction of this anomaly. Between June 1978 and June 1982, 12 patients with Ebsteins' anomaly underwent corrective open heart surgery at Seoul National University Hospital. Except for one patient, who had no ASD, all had a huge right atrium, secundum type ASD, and definite atrialized right ventricle. Typically, displaced tricuspid valve leaflets were found in all cases, but the degree of displacement and deformity were variable. In the point of NYHA functional classification, five were in class II, six were in class III, and one was in class IV. Ten patients were operated on by tricuspid valve replacement and pication. Two patients were operated on only by plication and annuloplasty techniques, and in all cases, ASD was closed. Postoperatively, four patients suffered from complete A-V block, and two of them died immediately. The remaining two patients took pacemaker generator implantation with good results. The other eight patients were in good condition. Tricuspid valve replacement using tissue valve and plication of the atrialized rght ventricle seems to be a good method of surgical correction for Ebstein's anomaly.

• Journal of Educational Research in Mathematics
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• v.24 no.2
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• pp.269-283
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• 2014

Recently, 3S Mathematics Education (Storytelling mathematics education, SMART mathematics education, and STEAM mathematics education) is emphasized. Based on recently published report on Storytelling mathematics textbook, we propose executable expression based SMART storytelling mathematics related to the elementary mathematic curriculum on 3D building blocks. We designed letters and expressions to represent three dimensional shape of 3D building blocks, and we compare its characteristics with that of LEGO blocks. We assert that text-based executable expressions not only construct what students want to make but also teachers can read students thinking process and can support educational help based on students needs. We also present linear function, quadratic function, and function variable concepts using executable expressions based on 3D building block as an example of SMART storytelling mathematics. This research was supported by the collaborated creativity mentoring project between Siheung City and college of education at Seoul National University. We hope designed executable expressions can be used for the development of SMART storytelling mathematics education.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.11a
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• pp.6-7
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• 2011

본 논문에서는 비대칭적 화질을 갖는 양안식 3DTV 시스템에서 좌우영상간의 화질차이가 크게 발생하는 경우, 열화된 우영상의 화질을 보상하기위한 부가정보로 양안시차 벡터맵을 사용하는데, 이때 넓은 대역폭을 갖는 부가정보를 효율적으로 부호화하여 전송하기위한 방법을 제안한다. 공간적인 중복성을 피하기 위해 쿼드트리 분해방식을 적용하였고, 양안시차 벡터의 시간적 중복성을 고려하여 부호화 효율을 높였다. 제안된 압축 알고리듬인 가변블록 부호화 방안을 적용한 복원영상은 비슷한 전송률을 갖는 고정블록 복원영상에 비해 개선된 PSNR을 가짐을 실험을 통해 확인하였다.

• Journal of Broadcast Engineering
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• v.12 no.3
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• pp.250-265
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• 2007

In this paper, a fast intermode decision scheme is introduced by efficiently performing the mode decision using statistical hypothesis testing for hierarchical B-picture coding of SVC, in which much computational power is expensed for combined variable block sizes and hierarchical B-pictures. The hypothesis testing in the proposed method is performed on $16{\times}16\;and\;8{\times}8$ blocks to have early termination for RD computation of all possible modes. The early termination in intermode decision is performed by comparing the pixel values of current blocks and corresponding motion-compensated blocks. The proposed scheme exhibits effective early termination behavior in intermode decision and leads to a significant reduction up to 69% in computational complexity with slight increment in bit amounts. The degradation of visual quality turns out to be negligible in terms of PSNR values.

• Journal of Hospice and Palliative Care
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• v.12 no.2
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• pp.88-94
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• 2009

Chest pain is a symptom observed commonly in outpatients and emergency room patients, and its causes are variable. Because treatment and prognosis of chest pain are different depending on its cause, it is more important than anything else to accurately diagnose the cause of chest pain. Most of patients complaining of chest pain undergo basic tests at a private local clinic or at the Internal medicine or chest surgery department of a general hospital and, they are referred to the pain clinic, with a note stating no particular finding. However, if they have sustained severe neuropathic pain in spite of nerve block, accurate diagnosis for chest pain is essential. We experienced rapidly developing spine breakdown and cord compression caused by metastatic spinal tumor in an inpatient who was being treated for chest pain, and thus, we report here in the case with literature review.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.10C
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• pp.820-828
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• 2008

In order to achieve high coding efficiency, H.264/AVC video coding standard adopts the techniques such as variable block size coding, motion estimation with quarter-pel precision, multiple reference frames, rate-distortion optimization, and etc. However, these coding methods have a defect to greatly increase the complexity for motion estimation. Particularly, from multiple reference frame motion estimation, the computational burden increases in proportion to the number of the searched reference frames. Therefore, we propose the method to reduce the complexity by controlling the number of the searched reference frames in motion estimation. Proposed algorithm uses the optimal reference frame information in both $P16{\times}16$ mode and the adjacent blocks, thus omits unnecessary searching process in the rest of inter modes. Experimental results show the proposed method can save an average of 57.31% of the coding time with negligible quality and bit-rate difference. This method also can be adopted with any of the existing motion estimation algorithm. Therefore, additional performance improvement can be obtained.

• 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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.2A
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• pp.137-145
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• 2002

In the method of 3D modeling, stereo matching method which obtains three dimensional depth information from the two images is taken from the different view points. In general, it is very essential work for the 3D modeling from 2D stereo images to estimate the exact disparity through fading the conjugate pair of pixel from the left and right image. In this paper to solve the problems of the stereo image disparity estimation, we introduce a novel approach method to improve the exactness and efficiency of the disparity. In the first place, we perform a wavelet transformation of the stereo images and set the reference points in the image by the feature-based matching method. This reference points have very high probability over 95 %. In the base of these reference points we can decide the size of the variable block searching windows for estimating dense disparity of area based method and perform the ordering constraint to prevent mismatching. By doing this, we could estimate the disparity in a short time and solve the occlusion caused by applying the fried-sized windows and probable error caused by repeating patterns.

• Polymer(Korea)
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• v.37 no.4
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• pp.431-436
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• 2013

Polycarbonate (PC) films have been irradiated with various kinds of ions according to energy and dose. Change of the optical transmittance and chemical characteristics were confirmed by UV-VIS and FTIR (ATR) spectroscopy respectively. These UV-A block in 400 nm was variable from 10 to 100% according to energy and doses. Surface electrical resistance of PC film irradiated by ion beam was $10^6-10^{13}{\Omega}/cm^2$, which reveal variation of conduction. Contact angle of film irradiated by ion beam was decreased than the pristine film. Polymer surface morphology was examined by means of atomic force microscopy (AFM). As expected, degradation of polymer film was higher after irradiation with heavier Xe ions but the roughness in the polymer surface morphology were more pronounced for Ar ions. This observed effect can be explained by stronger compaction of polymer surface layer in the case of Xe irradiation, connected with a reduction of free volume available.