DCT 영역에서 영상의 임의 비율 크기 변환을 위한 새로운 알고리즘

김용재,이창우,Kim, Yong-Jae,Lee, Chang-Woo 한국통신학회 2007 韓國通信學會論文誌 Vol.32 No.2C

유비쿼터스 통신 환경에서는 영상의 다양한 형태의 변환이 필수적인데, 대부분의 디지털 영상은 DCT (Discrete Cosine Transform)를 기반으로 한 JPEG, MPEG 등의 표준 기법을 이용하여 압축되어 저장되어 있다. 본 논문에서는 DCT 영역에서 영상의 크기를 변환시키는 기존의 여러 가지 알고리즘들을 고찰하고 그 성능을 분석하며, 기존의 방법보다 더 우수한 성능을 보이는 DCT 영역에서의 영상 크기 변환 알고리즘을 제안한다. 제안하는 알고리즘은 DCT 영역에서 영상의 임의 크기 변환을 위해 여러 개의 $8{\times}8$ DCT 계수 블록을 변환 비율에 따라 변환식을 통하여 하나의 블록으로 변환하고 최적의 zero-padding 및 truncating을 위한 IDCT의 크기를 정하는 방법을 이용하여 영상 크기 변환의 성능을 높인다. 이것은 화소간의 상관도를 최대한 이용하여 DCT 계수를 구하고, 여기서 얻어진 DCT 계수 블록에서 원하는 비율에 따라 최적의 크기를 구함으로써 성능을 높이는 알고리즘이다. 그 성능을 원 영상과 축소하여 다시 확대시킨 영상의 PSNR 비교를 통하여 확인하였고, 제안하는 알고리즘은 특정 비율의 변환에 있어서 기존의 알고리즘을 포괄할 수 있는 방법임을 확인할 수 있었다. In Ubiquitous communication environment, various conversions of images are essential, and most digital images are compressed by standard methods such as the Joint Photographic Expert Group (JPEG) and Motion Picture Expert Group (MPEG) which are based on the discrete cosine transform (DCT). In this paper, various image resizing algorithms in the DCT domain are analyzed, and a new image resizing algorithm, which shows superior performance compared with the conventional methods, is proposed. For arbitrary-ratio image resizing in the DCT domain, several blocks of $8{\times}8$ DCT coefficients are converted into one block using the conversion formula in the proposed algorithm, and the size of the inverse discrete cosine transform (IDCT) is decided optimally. The performance is analyzed by comparing the peak signal to noise ratio (PSNR) between original images and converted images. The performance of the proposed algorithm is better than that of the conventional algorithm, since the correlation of pixels in images is utilized more efficiently.

임하호의 (臨河湖) 식물성 플랑크톤 군집 분석

김용재,정준 ( Yong Jae Kim,Jun Chung ) 한국하천호수학회 1993 생태와 환경 Vol.26 No.3

This study investigated to the composition of phytoplankton community and its ecological factors in the Imha lake changed from the stream environment to the lake environment as the result by the construction of a multiple-purpose dam from Mar. to Dec. in 1992. Phytoplankton community was total 234 taxa composed of 7 class, 14 orders, 6 suborders, 39 families, 95 genera, 199 species, 25 variaties, 3 forma and 7 unidendifed species. The occurred taxa at each station and season ranged from 25 taxa at station 2 on May to 62 taxa at station 4 on May, which were very the wide variations at each station and season. The changes of standing crops were the maximum as 1.5×10^7unit/ℓat station 1 on Mar. and the minimum as 2.9×10^5unit/ℓat station 3 on Mar. Dominant Species were Achnanthes minutissima, Aulacoseira granulata var. angustissima, Cyclotella stelligera, Cymbella minuta var. silesiaca, Coelastrum cambricum, Phacotus lenticularis and Synedra delicatissima var. angustissima. The dominance index ranged from 0.15 to 0.76, and the diversity was very wide as the range from 0.23 to 1.05, also evenness diversed such as two index. The cluster analysis by similarity appeared the high relations with Aug. and Sept. at station 2 and the index was 0.88. Of the relationships between standing crops and physico-chemical factors, it was not the regularity between standing crop and chlorophyll concentration, and ranged from 0.89 at station 2 to negative index at other stations. Of dominant species, the relationships between Cyclotella stelligera and chlorophyll concentrations were the positive relations as up to 0.65 at all stations except to station 4.

MgO 증착률에 따른 PDP 보호막 물성 및 방전 특성 분석

김용재,권상직,Kim, Yong-Jae,Kwon, Sang-Jik 한국진공학회 2007 Applied Science and Convergence Technology Vol.16 No.3

본 연구에서는 플라즈마 디스플레이 패널의 방전 특성과 MgO 보호막 물성에 영향을 미치는 MgO 증착률에 대해 분석을 하였다. 물성 특성으로 결정 방향과 표면 거칠기 결정 구조 및 음극선 발광을 XRD (X-ray Diffraction), AFM (Atomic Force Microscopy), Mono-CL (Mono Cathode Luminescence analysis)등을 이용하여 측정하였고, 방전 특성으로는 방전개시전압과 방전 전류, 휘도를 진공 챔버와 오실로스코프 (TDS 540C), 전류 프로브 (TCP 312A), 휘도 색차계 (CS-100A)를 이용하여 측정하였다. 실험 결과 $5{\AA}/sec$의 증착률이 최적의 증착률임을 확인하였고, 또한 MgO의 증착률에 따라서 MgO 보호막의 물성특성이 변화하고 이에 의해서 전기적 광학적 특징이 영향을 받는 것을 확인하였다. 즉, 증착률 $5{\AA}/sec$을 기준으로 증착률이 증가할수록 (200) 결정 방향 및 음극선 발광의 밀도가 감소되고, 동작 전압은 증가하며 점차 효율이 나빠지는 경향을 보인다. We have investigated and analyzed the effects of the evaporation rate of MgO films on the MgO properties and the discharge characteristics of a plasma display panel(PDP). The MgO properties such as the crystal orientation, the surface roughness, the film structure, and cathode-luminescence (CL) spectra were inspected using XRD (X-ray diffraction), AFM(atomic force microscopy). And the discharging characteristics of the PDP such as the firing voltage, discharging current, and luminescence were measured using a vacuum chamber with oscilloscope (TDS 540C), current probe (TCP-312A), color meter (CS-100A) and etc. From the experiments results we confirmed the optimum evaporation rate at $5{\AA}/sec$, the MgO properties were shown to be strongly dependent on the evaporation rate, and the MgO properties had an effecton the optical and electrical characteristics. In other words, if the evaporation rates increase than $5{\AA}/sec$, the intensity of (200) orientation and cathode-luminescence (CL) spectra reduce, and the firing vlotage was increased. So the luminuous efficiency grows worse.

금호강 수계에서 Scenedesmus 속 개체군의 분석과 정점별 분포

김용재,박정원,정준 ( Yong Jae Kim,Chung Won Park,Jun Chung ) 한국환경생물학회 1993 환경생물 : 환경생물학회지 Vol.11 No.2

N/A

보문호에서의 훈장말 속 ( 녹조강 ) 에 대한 계절적 변화

김용재,정준 ( Yong Jae Kim,Jun Chung ) 한국하천호수학회 1992 생태와 환경 Vol.25 No.4

This study compared the seasonal variations of the species composition and standing crops of the genus Pediastrum in the steady state and the nonsteady state of water environment in the Pomun Lake from November, 1990 to October, 1991. It was identified 15 taxa which were 8 species, 7 varieties in the genus Pediastrum from this lake. The variations of monthly taxa numbers were from 11 taxa in November, 1990 to 4 taxa in August, 1991. The variations of standing crops were from 7.5×10^4 unit/l in November, 1990 to 8×10^2 unit/l in August, 1991, respectively. It was a positive correlation between the standing crops and physico-chemical factors (e.g. pH, water temperature, transparency, NH_4- N, PO_4- P). Also, the chlorophyll-a concentration was closely correlated with the changes of standing crops. In the steady state of water environment, the regular seasonal variations were the autogenic changes by the self-activity of the genus Pediastrum, but in the nonsteady state, the irregular seasonalities were the allogenic changes by the external factors(e. g. influx of external polluted material, and vertical and horizontal mixing by a localized torriential downpour), and retarded the velocity and disturbed the courses of succession.

남부지방에서 벼 재배형태별 분얼체계 및 수량구성형질의 차이에 관한 연구 I. 묘종류와 육묘시기에 따른 묘소질 및 본답 생육의 변화

김용재,신해룡,장강연,Kim, Yong-Jae,Shin-Hae-Ryong,Chang, Gang-Yeon 한국작물학회 1992 한국작물학회지 Vol.37 No.3

To study the effects of different nursing methods and transplanting on the growth of the rice plant(Oriza sativa L.hn southern region of Korea, Kumo-byeo, Palgong-byeo and Dong-jinbyeo were transplanted from April 20 to July 20 with 15 days intervals as 8 days seedling (infant rice), 25 days box seedling for machine transplanting and 45 days conventional seedling, respectively. No. of leaves at transplanting were in order of 45 days seedling>25 days seedling>8 days seedling. In 25 days seedling, they were increased as transplanting dates were later from April 20 to June 5, and in 45 days seedling, it showed same tendency until June 5 with Dongjinbyeo, June 20 with Palgong-byeo and Kumo-byeo. Root activity according to the $\alpha$-naphthylamine oxidation activity and rooting activity were higher in order of 8 days seedling>25 days seedling>45days seedling. Panicle formation initiated after maximum tillering stage as transplanting at April 20 with 8 days seedling and 25 days seedling, but it intiated before maximum tillering stage as transplanting at July 20 in Kumo-byeo. and in Palgong-byeo intiations of panicle formation were shown after maximum tillering stage as transplanting until May 20, but June 5 in Dongjin-byeo. However, there was no significant tendency with 45 days seedling. Missing hill ratio were less than 5% as transplanting with 8 days seedling and 25 days seedlingregardless of transplanting periods or varieties.

덕동호와 보문호의 식물플랑크톤에 대한 계절적 변화

김용재,김한순,정준 ( Yong Jae Kim,Han Soon Kim,Jun Chung ) 한국하천호수학회 1991 생태와 환경 Vol.24 No.4

The purpose of this study was to investigate the phytoplankton composition and agal biomass from Tokdong and Pomun lakes in Kyongju city, from May,1989 to April,1990. The authors have examined 139 taxa of the phytoplankton from Tokdong and Pomun lakes. These were composed of 5 classes, 10 orders, 3 suborders, 23 families, 50 genera, 110 species, 25 varieties and 4 forma. Agal biomass increased from 27 individuals/ml in January to 140 individuals/ml in November, at Tokdong lake and from 19 individuals/ml in January to 538 individuals/ml in August, at Pomun lake. Two peaks of chlorophyll-a concentration were observed in the surface water of both lakes, one in September and the other in February. Annual mean concentrations of chlorophyII-a were 4.6㎍/1 and 9.9㎍/1 in the surface water of Tokdong and Pomun lakes. Trophic states of both lakes were intermediate levels between oligotrohic and mesotrophic at Tokdong lake, and between mesotrophic and eutrophic at Pomun lake as the quantity of chlorophyll-a

차원해석을 이용한 사용후 핵연료 수송용기의 충격력 실험식 공식화

김용재,최영진,이영신,Kim Yong-Jae,Choi Young-Jin,Lee Young-Shin 한국전산구조공학회 2005 한국전산구조공학회논문집 Vol.18 No.3

방사성물질은 다양한 분야에서 사용되고 있으며 이에 따른 국내 및 국제간 운반이 계속적으로 증가하고 있다. 방사성물질을 수송하기 위해서는 수송용기의 안전성이 확보되어야 한다. 방사성물질 수송용기의 안전규정에 관해서는 국내 원자력법 운반안전규정 및 IAEA 운반규정에서 규정하고 있다. 방사성물질 수송용기 중에서 사용후핵연료를 운반하는 수송용기는 본체와 충격완충제로 구성되어 있다. 본 논문에서는 사용후핵연료 수송용기의 충격완충제에 작용하는 충격력을 계산하는 간편한 실험식을 차원해석을 통하여 유도하였다. 해석결과는 기존의 충격면적법 및 유한요소해석과 비교를 통하여 그 타당성을 입증하였다. 본 실험식을 이용하여 수송용기의 낙하충격력을 쉽게 예측할 수 있다. Radioactive material is used in the various fields. The numbers of transport for radioactive material have been gradually increased in both domestic and International regions. The safety of the cask should be secured to safely transport of radioactive material. The korean atomic law and the IAEA safety standards prescribe regulations lot the safe transport of radioactive material The cask for spent fuel is comprised of the body and the impact limiter. In this study, the empirical equation of the cask impact force is proposed based on the dimensional analysis. Using this empirical equation the characteristics of the impact limiter are analyzed. The results are also validated by comparing with the previous results of the impact area method and the finite element analysis. The present method can be used to predict the impact force of the cask.

기업간(B2B) 전자결재

김용재,Kim, Yong-Jae 한국전자정보통신산업진흥회 2001 電子振興 Vol.21 No.11

보문호에서의 (普門湖) Pediastrum clathratum ( Schroeter ) Lemmermann ( 녹엽망 (綠葉綱) 의 천이와 (遷移) 생태형

김용재,정준 ( Yong Jae Kim,Jun Chung ) 한국환경생물학회 1993 환경생물 : 환경생물학회지 Vol.11 No.1

According to the environmental fluctuations, it was changed with not only physico-chemical factors but also biological species composition and standing crops. In this water system, the authors investigated the total standing crops, standing crops and composition ratio of each morphotype of Pediastrum clathratum from Nov. 1990 to Oct. 1991 and established the ecotype. Physico-chemical factors were changed uniformly in the steady state water system, but changed dramatically as the nonsteady state from June to Oct. 1991 by a torrential rain. Changes of standing crops of P. clathratum were ranged from the 7.0×10 exp (4)unit/ℓ in Nov. 1990 to 1×10 exp (2)unit/ℓ in Aug. and Sept. 1991. Of seasonal changes of each morphotype, A-2 morphotype occurred during the all months and showed the highest standing crops and composition ratio. Therefore, the authors treat A -2 morphotype as the ecotype (e.g. P. biwae form) by the seasonal changes of steady state, eury-adaptation, the highest standing crops and composition ratio.