데이타플로우 컴퓨터에서 Sparse한 행렬과 벡터의 내적 수행시 성능 평가

李暻敏,李龍頭,蔡洙煥 한국항공대학교 1992 論文集 Vol.30 No.-

실 시간 처리 분야에서 요구하는 컴퓨터 시스템의 성능을 만족시키기 위하여 병렬처리 시스템에 대한 연구가 활발히 진행되고 있다. 본 연구에서는 병렬처리 시스템들 중에 병렬성 구현 정도가 뛰어난 정적 데이타플로우 컴퓨터의 구조에서 최대의 병렬성, 적정 프로세서의 수, 대기 행렬의 수, 속도 향상등을 평가하기 위해 시뮬레이터를 구성하였다. 병렬로 처리될 수 있는 부분들이 많이 존재하는 sparse한 행렬로 벡터의 내적을 구하는 문제들을 시뮬레이션 하였다. 시뮬레이션에 있어서, 필요한 명령들의 처리 시간을 8086프로세서를 기준으로 한 실제적인 경우로 주었다. Research on parallel processing systems is very active to satisfy the computer performance required in real-time processing fields. In this research, a simulator is implemented to evaluate the maximum parallelism, the proper number of processors, the size of queue and the speed up factor on static dataflow computer architectures which can be expressed parallelism naturally. Inner product of sparse matrices and vectors is chosen to evaluate the performance of static dataflow architectures. In the simulation, ideal execution times and real execution times based on the 8086 processor are applied.

Antioxidant, Anti-Melanogenic and Anti-Wrinkle Effects of Phellinus vaninii

( Kyung Hoan Im ),( Seung A Baek ),( Jaehyuk Choi ),( Tae Soo Lee ) 한국균학회 2019 Mycobiology Vol.47 No.4

In this study, the antioxidant, anti-xanthine oxidase, anti-melanogenic and anti-wrinkle effects of methanol (ME) and hot water (HE) extracts from the fruiting bodies of Phellinus vaninii were investigated. The 1,1-diphenyl-2-picryl-hydrazyl free radical scavenging activity of 2.0mg/mL HE (95.38%) was comparable to that of butylated hydroxytoluene (96.97%), the reference standard. The hydroxyl radical scavenging activities of ME (98.19%) and HE (97.55%) were higher than that of butylated hydroxytoluene (92.66%) at 2.0mg/mL. Neither ME nor HE was cytotoxic to murine melanoma B16-F10 cells at 25-750 mg/mL. Although the xanthine oxidase (XO) inhibitory effects of ME and HE were significantly lower than that of allopurinol, the values were higher than 84 percent. The in vitro tyrosinase inhibitory activities of ME and HE were comparable to kojic acid at 2.0mg/mL. The cellular tyrosinase and melanin synthetic activities of ME and HE on B16-F10 melanoma cells at 500 mg/mL were higher than arbutin, indicating that the inhibitory effects of arbutin on the tyrosinase and melanin synthesis were higher than those of ME and HE. The collagenase inhibitory activity of HE was comparable to EGCG at 2.0mg/mL, however, the elastase inhibitory activity of ME and HE was lower than EGCG at the concentration tested. The study results demonstrated that the fruiting bodies of Ph. vaninii possessed good antioxidant, anti-xanthine oxidase, cell-free anti-tyrosinase, cellular anti-tyrosinase, anti-collagenase, and moderate anti-elastase activities, which might be used for the development of novel anti-gout, skin-whitening, and skin anti-wrinkle agents.

Effects of Abiotic Stresses on Cell Cycle Progression in Tobacco BY-2 Cells

Kyung Hoan Im,Ky Young Park,Su Jin Jang,Sung Hae Shin,Sung Tae Yee,Baek Hwang 한국분자세포생물학회 2005 Molecules and cells Vol.20 No.1

Mild stresses such as high temperature (30°C) or a low H2O2 concentration induced transient cell cycle arrest at G1/S or G2/M depending on the cell cycle stage at which the stress was applied. When stresses were introduced during G0 or G1, the G1/S checkpoint was mainly used; when stresses were introduced after S phase, G2/M was the primary checkpoint. The slowing of cell cycle progression was associated with transient delays in expression of A-, B-, and D-type cyclins. The delay in expression of NtcycA13, one of the A-type cyclins, was most pronounced. The levels of expression of Ntcyc29 (a cyclin B gene) and of CycD3-1 differed most depending on the applied stress, suggesting that different cellular adjustments to mild heat and a low concentration of H2O2 are reflected in the expression of these two cyclin

Cloning of Genes Differentially Expressed during the Initial Stage of Fruit Development in Melon (Cucumis melo cv. Reticulatus)

Kyung Hoan Im,Jung Woo Choi,Gun Bo Kim,Yun Chan Huh,Mi Ra Kwon,Il Gin Mok,Jung Wan Kim,Tae Soo Lee,Shinje Kim 한국분자세포생물학회 2004 Molecules and cells Vol.17 No.2

We have cloned genes involved in the initial stage of fruit development in the melon by suppression subtrac-tive hybridization. A cDNA library of unfertilized ovules was subtracted from that of fruit 9 days after pollina-tion (DAP); 10 of the 40 selected cDNA clones were identified by reverse Northern analysis as genes differ-entially expressed in fruit at 9 DAP. Seven of the ten genes were homologous to genes of known function; two were related to genes with unknown functions, and one was novel. With the exception of cucumisin, none of the cDNAs had been previously identified in melon. Accord-ing to Northern analyses, six of the genes were ex-pressed at high levels early in fruit development. Ex-pression of cucumisin, Cmf-25, Cmf-30, and Cmf-124 was highest at 9 DAP, implying that these genes are in-volved in the initial stage of fruit development. Cmf-30, a seed nucellus-specific gene, was also expressed early in seed development. The other genes were expressed at a moderate level throughout fruit development, with the highest expression occurring in fruit at 9 and 18 DAP. In conclusion, nine new genes involved in early fruit development in melon were cloned, and their temporal and spatial expression patterns indicate that they are preferentially expressed during the active growing stage of fruit.

Hyperlipidemic Inhibitory Effects of Phellinus pini in Rats Fed with a High Fat and Cholesterol Diet

( Kyung Hoan Im ),( Jaehyuk Choi ),( Seung-a Baek ),( Tae Soo Lee ) 한국균학회 2018 Mycobiology Vol.46 No.2

This study evaluated the in vitro and in vivo hypolipidemic effects of the medicinal mushroom Phellinus pini. The methanol extract (ME) of the fruiting body of Ph. pini was active against pancreatic lipase and cholesterol esterase with 99.14% and 67.23% inhibited activity at 1.0 mg/mL, respectively. It also inhibited 81.81% and 55.33% of a-glucosidase and a-amylase activities, respectively, at 2.0mg/mL. Hyperlipidemia as induced by feeding rats with a high fat and cholesterol diet (HFC). HFC supplemented with a 5% fruiting body powder of Ph. pini (HFCþPhP) significantly reduced plasma total cholesterol, low-density lipoprotein cholesterol, and triglycerides in rats compared with HFC. The reduced levels were comparable to rats fed the normal control diet (NC). The atherogenic index of HFCþPhP rats was significantly lower than that of the HFC rats. The excretion of fecal total lipid and cholesterol in the HFCþPhP rats was significantly higher than those in the NC and HFC rats. Histopathological examinations demonstrated scant deposition of lipids in the liver of rats fed HFCþPhP. The dietary supplementation with the fruiting body powder provided natural plasma lipid and glucose lowering effects in experimental rats without adverse effects on the plasma biochemical parameters and liver function related enzyme activities. Therefore, the hypolipidemic effects of Ph. pini may be due to the inhibitory effects on pancreatic lipase, cholesterol esterase, a-glucosidase, and a-amylase, and excretion of excess lipids and cholesterol in the feces.

Ethanol Production from Various Sugars and Cellulosic Biomass by White Rot Fungus Lenzites betulinus

Im, Kyung Hoan,Nguyen, Trung Kien,Choi, Jaehyuk,Lee, Tae Soo The Korean Society of Mycology 2016 Mycobiology Vol.44 No.1

Lenzites betulinus, known as gilled polypore belongs to Basidiomycota was isolated from fruiting body on broadleaf dead trees. It was found that the mycelia of white rot fungus Lenzites betulinus IUM 5468 produced ethanol from various sugars, including glucose, mannose, galactose, and cellobiose with a yield of 0.38, 0.26, 0.07, and 0.26 g of ethanol per gram of sugar consumed, respectively. This fungus relatively exhibited a good ethanol production from xylose at 0.26 g of ethanol per gram of sugar consumed. However, the ethanol conversion rate of arabinose was relatively low (at 0.07 g of ethanol per gram sugar). L. betulinus was capable of producing ethanol directly from rice straw and corn stalks at 0.22 g and 0.16 g of ethanol per gram of substrates, respectively, when this fungus was cultured in a basal medium containing 20 g/L rice straw or corn stalks. These results indicate that L. betulinus can produce ethanol efficiently from glucose, mannose, and cellobiose and produce ethanol very poorly from galactose and arabinose. Therefore, it is suggested that this fungus can ferment ethanol from various sugars and hydrolyze cellulosic materials to sugars and convert them to ethanol simultaneously.

BLDC모터 속도제어 성능 개선을 위한 새로운 PI-P제어기에 관한 연구

이경환(Kyung-Hoan Lee),조내수(Nae-Soo Cho),권우현(Woo-Hyen Kwon),최연호(Youn-Ho Choi),임성운(Sung-Woon Im) 전력전자학회 2010 전력전자학술대회 논문집 Vol.2010 No.7

BLDC 모터의 속도제어기로 주로 사용되는 PI제어기의 응답 성능을 개선하기 위하여 본 논문에서는 PI-P구조를 가지는 새로운 속도 제어기를 제안한다. 제안된 방법은 PI 제어기의 출력과 시스템의 출력의 차에 P 이득을 추가하는 방법이다. 추가된 P 이득으로 인해 기존의 제어기에서 발생되는 오버슈트와 느린 정착시간을 개선 할 수 있다. 제안된 방법의 성능을 확인 하기 위해서 Matlab Silmulink를 이용한 모의실험을 통해 제안된 제어기의 유용성를 확인한다.

DC-DC Buck Converter의 응답특성 해석 및 연구

이경환(Kyung-Hoan Lee),김진덕(Jin-Deok Kim) 전력전자학회 2013 전력전자학술대회 논문집 Vol.2013 No.7

Antioxidant and inflammation inhibitory effects from fruiting body extracts of Ganoderma applanatum

Im, Kyung Hoan,Choi, Jaehyuk,Baek, Seung A,Lee, Tae Soo The Korean Society of Mushroom Science 2021 한국버섯학회지 Vol.19 No.4

In this study, the antioxidant and anti-inflammatory effects of methanol extract (ME) and hot water extracts (HE) from the fruiting bodies of Ganoderma applanatum were investigated. The 1,1-diphenyl-2-picryl-hydrazy (DPPH) radical scavenging activity of 2.0 mg/mL ME (94.83%) was comparable to that of butylated hydroxytoluene (96.97%), the reference standard. The hydroxyl radical scavenging activities of ME and HE were similar to that of BHT at 2.0 mg/mL, whereas lipid peroxidation activity of the ME and HE were significantly lower than that of BHT. High-performance liquid chromatography analysis showed that the G. applanatum fruiting bodies contained nine phenolic compounds, which might contribute to antioxidant and anti-inflammatory activities. The survival rate of RAW 264.7 macrophages treated with 2.0 mg/mL ME and HE were 65.23 to 68.12% at 2.0 mg/mL, thereby indicating that the extracts were slightly cytotoxic at the concentration tested. The extracts also inhibited the nitric oxide (NO)-mediated expression of inducible nitric oxide synthase (iNOS) protein in lipopolysaccharide-induced RAW 264.7 macrophages and carrageenan-induced paw edema in rats. The study results demonstrated that the fruiting bodies of G. applanatum possessed good antioxidant and anti-inflammatory activities, which might be used to develop novel anti-inflammatory agents.

새로운 PI-P 제어기를 이용한 BLDC Motor의 속도제어에 관한 연구

이경환(Kyung-Hoan Lee),조내수(Nae-soo Cho),권우현(Woo-Hyen Kwon),김우현(Woo-Hyun Kim),박철우(Chul-Woo Park) 대한전기학회 2010 대한전기학회 학술대회 논문집 Vol.2010 No.4

BLDC 모터의 속도제어기로 주로 사용되는 PI제어기의 응답성능을 계선하기 위하여 본 논문에서는 PI-P구조를 가지는 새로운 속도 제어기를 제안한다. 제안된 방법은 PI 제어기의 출력과 시스템의 출력의 차에 P 이득을 추가하는 방법이다. 추가된 P 이득으로 인해 기존의 PI 제어기에서 발생되는 오버슈트와 느린 정착시간을 개선 할 수 있다. 제안된 방법의 성능을 확인하기 위해서 Matlab Silmulink를 이용하여 기존 PI 제어기와 제안된 제어기의 모의실험을 통해 비교 하였다. 모의실험 결과 제안된 방법이 기존의 PI제어기 보다 우수한 성능을 보임을 확인 하였다.