Improved DCT-Based Image Coding and Decoding Methods For Low-Bit Rate Applications

Jung, Sung-Hwan,Sanjit K. Mitra 國立 昌原大學校 基礎科學硏究所 1994 基礎科學硏究所論文集 Vol.6 No.-

The discrete cosine transform (DCT) is well known for highly efficient coding performance, and it is widely used in many image compression applications. However, in low-bit rate coding, it produces undesirable block artifacts that are visually not pleasing. In addition, in many applications, faster computation and easier VLSI implementation of DCT coefficients are also important issues. The removal of the block artifacts and faster DCT computation are therefore of practical interest. In this paper, we outline a modified DCT computation scheme that provides a simple efficient solution to the reduction of the block artifacts while achieving faster computation. We also derive a similar solution for the efficient computation of the inverse DCT. We have applied the new approach for the low-bit rate coding and decoding of images. Initial simulation results on real images have verified the improved performance obtained using the proposed method over the standard JPEG method.

상호상관 함수를 이용한 지중선로 고장점 추정

朴星完,林泳範,鄭州桓,成洛煥,金喆煥,申明徹 成均館大學校 科學技術硏究所 1994 論文集 Vol.45 No.2

This paper is intended as an investigation of fault location for underground line. Over the past few decades a considerable number of studies have been made on protection of underground line. However, these approaches require the interruption of electric power supply from source for fault location estimation. Therefore, we proposed fault location algorithm for underground line protection without interruption of electric power supply. Cross correlation function is used in this algorithm. Also, EMTP data is used to demonstrate the capability of the proposed fault location algorithm.

동종 골수 이식한 백혈병에서 단반복 유전자로 살펴본 혼합 키메라 현상의 의의

장대영,이정신,서철원,이규형,이제환,지현숙,박찬정,한면수,최동원,김정균,최성준,김성배,김상위,김우건,김상희 대한조혈모세포이식학회 1998 대한조혈모세포이식학회지 Vol.3 No.1

연구배경 : 동종 골수 이식한 백혈병에서 키메라 현상의 분석은 착상, 질병 재발과 이식 거부를 이해하는데 도움을 줄 수 있다. 최근 STR을 PCR로 증폭한 검사법에 의해 매우 민감하고 유용하게 혼합 키메라 현상을 검출할 수 있다고 보고되고 있으나, 이 방법의 민감도와 임상적 의의는 아직 완전히 정립되지는 않았다. 따라서 PCR-STR검사법이 혼합 키메라 현상을 민감하게 검출하는지 보고, 동종 골수 이식 후 혼합 키메라 현상의 변화 양상을 관찰하고, 키메라 현상의 임상적 의의를 보고자 하였다. 방법 : 형제로부터 동종 골수 이식한 급성 백혈병 6명과 만성 백혈병 2명의 모두 8명을 대상으로 하였다. 44개 골수 검체에서 phenol/chloroform방법에 의하여 단핵세포 DNA를 추출하였다. DNA는 CTT 삼중체, vWA와 amelogenin시발체를 이용하여 증폭하였다. 증폭 산물은 5% 폴리아크랄아미드 젤에서 전기영동 뒤 은 염색으로 확인하였다. 2명의 DNA를 여러 비율로 혼합하여 상기 검사를 하여 검출 가능 최소 농도를 결정하였다. 결과 : 상기 검사법의 검출 가능 최소농도는 0.25%였다. 혼합 키메라 현상은 8명중 4명에서 관찰되었다. 혼합 키메라 현상은 보인 1명에서 급성 및 만성 이식편대 숙주 질환이 나타났고, 완전 공여자 키메라 현상을 보인 1명에서 만성 이식편 대 숙주 질환이 나타났다. 점진적으로 증가하는 혼합 키메라 현상을 보인 2명은 이식 후 12개월에 질병 재발을 보였으나, 완전 공여자 키메라 현상을 보인 경우엔 재발이 관찰되지 않았다. 결론 : PCR-STR검사법은 동종 골수 이식 후 남아 있는 환자 세포를 검출하고 키메라 현상을 관찰하는데 유용한 방법이다. 또한 이 검사법은 동종 골수 이식 후 재발의 조기 진단, 이식편 대 숙주 질환의 평가와 면역 관용에 임상적으로 응용할 수 있으리라 생각한다. Background : Chimerism analysis after allogeneic bone marrow transplantation (BMT) for leukemia could be helpful understanding of the early marrow engraftment, disease relapse, and graft rejection. Recently, a PCR technique which amplifies short tandem repeats(STR) has been reported to be highly sensitive and reliable in detecting mixed chimerism. But its sensitivity and clinical significance has not been established. The purpose of this study was firstly, to confirm whether a PCR-STR in highly sensitive enough ti assess mixed chimerism, secondly to monitor the changing patterns of mixed chimerism after allogeneic BMT, and lastly to determine correlation between the chimeric status and the clinical outcome. Methods : A study was made eight patients (six with acute leukemia and two with chronic leukemia) who underwent unmanipulated allogeneic BMT along with matched donors. DNA was extracted from mononuclear cells of 44 bone marrow samples using a phenol/chloroform method. Amplification of DNA was done using CSFIPO-TPOX-TH01(CTT) triplex with or without vWA or amelogenin primer. The amplified product was separated on 5% polyacrylamide gel and was confirmed by silver staining. The sensitivity of CTT triplex method was determined by mixing DNA from two person in serial proportion using the same method. Results : The sensitivity for CTT triplex method was 0.25% Mixed chimerism was documented in 4 of 8 patients. ONe of four patients with mixed chimerism developed acute and chronic graft versus host disease (GVHD) and one of four patients with complete donor chimerism also developed chronic GVHD. Two patient with progressive mixed chimerism relapsed at 12 months post-BMT, whereas no patient with complete donor chimerism has relapsed. Conclusion : The study has found that PCR-STR was an effective method for the detecting residual host cell and monitoring the chimeric status after allogenic BMT. PCR-STR can also be clinically applicable in early prediction of relapse, appropriate assessment of GVHD, as well as tolerance after allogeneic BMT.

서울의 Penicillinase Producing Neisseria Gonorrhoeae 발생빈도(1996)

김재홍,황동규,전재홍,김윤석,김중환,김용준,이창균,임동진,김현수,조창근,김경문,박상훈,전우형,김희성,이호정,차명수,김갑형,김형석,김석우,황지환,박병순,권오상,이민수,송기훈,성소영,이인섭,부태성 대한화학요법학회 1999 대한화학요법학회지 Vol.17 No.2

Background : In recent years, gonorrhea has been panedemic and remains one of the most commom STDs in the world, especially in developing countries. Objective & Methods: For the detection of a more effective therapeutic regimen and assessing the prevalence of PPNG, we have been trying to study the patients who have visited the VD Clinic of Choong-Ku Public Health Center in Seoul since 1980 by means of the chromogenic cephalosporin method. Results: In 1996, 139 strains of N. gonorrhoeae were isolated, among which 53(39.0%) were PPNG. Conclusion: Our results suggests that after a peak of 74.3% in 1993, the prevalence of PPNG in Seoul is gradually declining.

2형 당뇨 환자에 있어서 C형 간염의 유병률에 관한 연구

김구영,서광섭,유광렬,임병욱,채선애,강남훈,김창훈,권영우,김희수,류성태,이정환,박성우,오웅식,김정한 중앙대학교 의과대학 의과학연구소 2003 中央醫大誌 Vol.28 No.1

Background: We have doubt about the truth that Type 2 DM is associated with chronic hepatitis C infection. The aim of our study was to prove a close relationship between chronic HCV infection and type 2 DM in korean patients. Methods: We reviewed the out-patient's medical records of 466 patients with type 2 DM who visit the Sung-ae hospital from March 2000 to August 2001. Diabetic patients were analyzed for the following variables: age, sex, waist circumference, weight, waist/hip ratio, using of self monitoring of blood glucose, method of therapy, duration of disease, experience of previous transfusion, major surgical procedure, accompanied disease, liver function tests (LFT), HbA1 c. We ruled out patients with liver cirrhosis. Results: Hepatitis C virus infection was observed more frequently in patient with Type 2 DM. Of 466 Type 2 DM patients, 13 patients were infected with Hepatitis C virus (2.79%). Compared with mean prevalence of Korean population (1.3~1.6%), it's value is very high. the other hand, 21 patients were infected with Hepatitis B virus (4.5%). Such results are similar to mean prevalence of the general public (4~5%). Conclusions: Prevalence of hepatitis C was closely associated in korean patients with type 2 DM. And an increased prevalence is independent of cirrhosis.

근사 DCT와 움직임 보상을 이용한 연속 영상 부호화 기법 연구

정성환 國立昌原大學校 基礎科學硏究所 1994 基礎科學硏究所論文集 Vol.6 No.-

A simple and fast image coding technique using an approximate DCT and a motion compensation is proposed. Through the experiment using a real image sequence SALESMAN, it shows faster performance and less blocking effects than the conventional DCT-based sequence coding method.

Ogive-Cylinder 형 첨두부를 갖는 유도무기 주위 고앙각 흐름에서의 비대칭 와류 특성과 이에 따른 측력발생에 대한 수치적 해석 연구

정성기,제상언,명노신,조태환 慶尙大學校 經營行政大學院 2004 工學硏究院論文集 Vol.20 No.-

The demand for continually increased performance of missiles and aircraft leads to considering flight at very high angle of attack where control is very difficult. This is mainly due to shedding of asymmetric vortices from the forebody, producing side forces even at zero sideslip. In this paper, Computational Fluid Dynamics(CFD) was used to analyze characteristic of asymmetric vortices and examine the effects of several cases for rising asymmetric vortices. There are asymmetric grid cluster, sideslip angle and roughness. As a result of the study, asymmetric vortices were sensitive at the areas of roughness and the analysis results coincided with the experiment results at the specified area.

ADALINE을 이용한 훼손된 영상에 대한 에지검출 연구

鄭聖煥,禹容泰 國立昌原大學校 基礎科學硏究所 1992 基礎科學硏究所論文集 Vol.3 No.-

The edge detection technique using neural network is discussed for some noisy images. It is compared with conventional edge detection techniques by the subjective measure and objective. The edge detection technique of neural network shows better performance than others in some noisy environments.

RAPD와 핵 리보솜 DNA ITS2 염기서열에 의한 한국산 전나무속 식물의 유전적 변이 및 계통유전학적 분석

정용환,한상현,오유성,고미희,고석찬,김문홍,오문유 濟州大學校 基礎科學硏究所 2001 基礎科學硏究 Vol.14 No.2

We analyzed the genetic variation and phylogenetic relationship among fourteen taxa of GenusAbies distributed in Korea using random amplified polymorphic DNA (RAPD) and internal transcribed spacer (ITS) 2 sequences of the nuclear ribosomal DNA (rDNA). RAPDs were used for identification of selected taxa by amplification using single 10-mer primers of arbitrary sequence. Fourteen taxa were clearly classified with 10 arbitrary primers, which generated 102 useful polymorphic bands that were evaluated according to the presence or absence of the fragments of equal size. The genetic distance between A. koreana for. chlorocarpa and A. koreana for. rubrocarpa was 0.127, showing the closest among any other pairs. By comparing the base sequences in the ITS2 region of the nuclear rDNA, genetic relationship was assesed among selected taxa. It showed twenty six sites of point mutation (base substitution) in 243 base pairs (bp) of ITS2 region. The G+C contents of ITS2 region were ranged from 58.3% to 61.7%. The value of nucleotide divergence among selected taxa was ranged from 0.4% to 9.8%. These results showed that RAPD and ITS2 sequence analysis was a useful tool for elucidating phylogenetic relationship and selection of specific marker in Abies species.

가우시안 믹스쳐 분석을 이용한 클러스터 기반의 계층적 영상 검색

정성환,이우선 창원대학교 산업기술연구소 2001 産技硏論文集 Vol.15 No.-

A cluster-based image retrieval was studied. It retrieves images from a related cluster after classifying images into clusters using RAGMD, a clustering technique. When we retrieve images, we first retrieve images not from the whole image database one by one but from the similar cluster, a similar small image group with a query image. So it gives us retrieval-time reduction while keeping almost the same precision as the exhaustive retrieval. In the experiment using an image database which consists of about 2,400 real images, the proposed method showed that it is about 18 times faster than the exhaustive method with almost same precision and it can retrieve more similar images which belong to the same class with a query image.