스마트 기기의 효율적인 I/O를 위한 플래시 파일 시스템 성능 분석

정경호,김용환,김상진,정영석,김성수,Chung, Kyung-Ho,Kim, Yong-Hwan,Kim, Sang-Jin,Jung, Young-Seok,Kim, Sung-Soo 대한임베디드공학회 2015 대한임베디드공학회논문지 Vol.10 No.3

Recently NAND flash memory has been found to be the primary cause of low performance in the smart device. NAND flash memory is different from each other the execution time of I/O operations that flash file system is required. Therefore, it is necessary to compare and analyze the flash file system I/O performance for the efficient I/O on smart device. In this paper, it was tested and analyzing the I/O performance of the YAFFS2, JFFS2, UBIFS. Experimental results most read I/O performance is good, but the writing I/O performance is not good. For UBIFS, showed a more good I/O performance compared to other flash file system.

연구논문 - 화학공정분과 : 테르펜 수지에 의한 폴리아미드계 핫멜트 접착제의 인장거동 및 유변학적거동의 조절

정경호,서봉성,홍영근,전영식 ( Kyung Ho Chung,Bong Sung Suh,Young Keun Hong,Young Sik Chun ) 한국공업화학회 1997 한국공업화학회 연구논문 초록집 Vol.1990 No.3

레소시놀계와 탄닌계 접착제의 고무산업에 응용

정경호,Chung, Kyung-Ho 한국고분자학회 1997 고분자 과학과 기술 Vol.8 No.6

폴리아미드계 수지를 이용한 핫멜트 접착제의 기능향상 - (Ⅱ) 테르펜수지의 영향 -

정경호,홍영근,전영식 ( Kyung Ho Chung,Young Keun Hong,Young Sik Chun ) 한국공업화학회 1998 공업화학 Vol.9 No.2

핫멜트 접착제는 최근 대두되고 있는 환경적인 요구사항들을 충족시킬 수 있는 무용제형이고 접착공정의 자동화가 가능하기 때문에 널리 사용 되고 있다. 본 연구에서는 핫멜트 접착제의 기본 수지로서 폴리아미드 단일중합체 대신 나일론 6, 나일론 66, 나일론 12로 이루어진 CM831(랜덤중합체)과 843P(블록중합체) 형의 두 종류 수지를 사용하여 핫멜트 접착제를 제조하였다. 결과에 의하면 접착제 자체 강인성을 크게 손상하지 않는 범위에서 가능한 한 낮은 용융점도를 갖는 조건은 CM831/843P 수지 블랜딩 비율이 약 75/25∼50/50임을 알 수 있었다. 접착성 향상과 더불어 피착제와의 젖음 특성 향상을 위해 점착부여 수지로 테르펜 수지를 사용하였다. 테르펜 수지는 약 10 wt.% 첨가되었을때 현 시스템의 용융온도와 용융점도를 감소시키고, 접착제 자체 강인성은 증가시키는 접착제 측면에서 바람직한 결과를 나타냈다. 또한 접착제의 유변학적 특성도 전형적인 비뉴턴 거동으로부터 테르펜수지 첨가로 인해 뉴턴 거동에 가까워졌다. Hot melt adhesive which is solventless type has been widely used due to the possibility of automated adhesion process. The main purpose of this study is the development of polyamide based hot melt adhesive to improve the property of conventional ethylene-vinyl acetate hot melt adhesive, which has an inherent problem against heat resistance. In this study, it was found that the terpolymers of nylon 6, nylon 66, and nylon 12(CM831, 843P types) instead of nylon homopolymer were suitable base resins for hot melt adhesive, since the disruption of regularity in the polymer chains reduced the crystallinity, resulting in lower melting point and melt viscosity. According to the results, the optimum adhesion property could be obtained by the using 75/25∼50/50 weight ratio of CM831/843P resin as a base resin. Terpene resin was used as tackifier to improve adhesion and wetting properties. The best result can be obtained with the 10 wt.% addition of terpene resin. The terpene resin acted as proper tackifier in this system, which decreased the melt temperature and viscosity, but increased the mechanical strength of adhesive itself. Also, the rheological property of the adhesive changed from typical non-Newtonian behavior to Newtonian behavior as terpene resin was added.

서해 경기만의 기초생산력 및 질소계 영양염의 재생산에 관한 연구

정경호,박용철,Chung, Kyung Ho,Park, Yong Chul 한국해양학회 1989 韓國海洋學會誌 Vol.23 No.4

Seasonal variations of nutrients (ammonium, nitrite, nitrate, phosphate and silicate), primary productivity and ammonium regeneration rate of macrozooplankton were investigate to understand the relationship between nitrogen recycling and nitrogen requirement by phytoplankton from Feburuary 1986 to November 1987 in the Kyunggi Bay, shallow estuarine water of Yellow Sea. In general, nutrients increased during the winter and depleted during the spring and the early summer except temporally sharp increase after flood in September. Ammonium was prevalently generally found in high concentration throughout the study area and it occasionally raised N/P ratio in the range of 30 to 70 as in the freshwater environment. Daily net primary productivity ranged from 30.3 to 3580.0 mgC/$m^2$/d with an average of 883.9 mgC/$m^2$/d. Annual primary productivity was determined to be 320.0 gC/$m^2$/yr. Carbon assimilation number ranged from 2.9 to 19.4 mgC/mg chl-a/h which increased in the summer and decreased in the winter. Nitrogen requirement by phytoplankton ranged from 0.4 to 45.0 mg at-N/$m^2$/d and turnover time of inorganic nitrogen ranged from 2.4 in the late summer to 122.7 days in the winter. Nitrogen regeneration rate of mixed macrozooplankton determined by bottle incubation method ranged from 0.02 to 1.34 mg at-N $m^2$/d and it could contribute from 2.8 to 38.7% with an annual average of 14.9% of total nitrogen requirement by phytoplankton in this shallow estuarine environment.

폴리아미드계 수지를 이용한 핫멜트 접착제의 기능 향상 -(3) 왁스와 충전제의 영향 -

정경호 ( Kyung Ho Chung ),한경아 ( Kyung A Han ),조욱상 ( Wook Sang Cho ) 한국공업화학회 2005 공업화학 Vol.16 No.6

In vitro plant regeneration from flower buds of populus deltoides and P. maximowiczii

정경호(Kyung Ho Chung),김주학(Joo Hag Kim),전영우(Young Woo Chun) 한국육종학회 1993 한국육종학회지 Vol.25 No.3

Small immature flower buds of Populus deltoides and P.maximowiczii were cultured on the MS medium containing 0.5㎎/ℓ BA and 0.5-1.0㎎/ℓ NAA for development and growth. Small slices of catkin 5-6㎜ in thickness prepared from the well-developed flower bud 3-4㎝ in length were culture on the MS medium containing 1.0㎎/ℓ BA+0.05㎎/ℓ NAA and 0.5㎎/ℓ BA+0.05㎎/ℓ NAA for adventitious shoot regeneration from P.deltoides and P.maximowiczii, respectively. Average 3.8 shoots from P.deltoedes and 4.1 from P.maximowiczii were regenerated from a slice of catkin. More than 20 shoots can be regenerated from a single mature catkin of poplar such as P.deltoides that is recalcitrant to shoot regeneration. Adventitious shoots were initiated from three different places of an explant, the outer and the cut surface of stalks, and the marginal part of small bracts. The development of immature flower buds in vitro was affected by collecting time. Those collecting in late March were not developed well into mature flower buds. among five different collecting times, July, Sep., Nov., Jan., and Mar.

자기장 응답형 엘라스토머 개발을 위한 기초연구

정경호 ( Kyung Ho Chung ),윤규서 ( Kyu Seo Yoon ) 한국고무학회 2010 엘라스토머 및 콤포지트 Vol.45 No.2

천연고무와 실리콘고무에 자기장응답형 분말을(Magnetic Responsible Powder; MRP) 배합하여 자기장응답형 엘라스토머(Magneto-rheological Elastomer; MRE)를 제조하였다. MRP의 최적 사용량은 30 vol.% 였으며 천연고무 기반 MRE의 기계적 물성은 실리콘고무 기반 MRE 보다 우수했지만, magneto-rheological (MR) 효과는 실리콘고무 기반 MRE가 더욱 우수하였다. MR 효과는 Self-modified Electromagnet Applied Fast Fourier Transform Analyser (SEFFTA)를 사용하여 측정되었는데 천연고무 기반 MRE의 경우는 10%, 실리콘고무 기반 MRE의 경우는 최대 35.7%까지 나타내었다. 네오디뮴 자석을 이용하여 MRE를 경화시키기 전 MRP를 선 배향 시킬 경우 더욱 우수한 MR 효과를 얻을 수 있었으며, MRP의 배향은 주사전자현미경을 이용하여 분석하였다. Magneto-rheological elastomers (MREs) were manufactured by incorporation of magnetic responsible powder (MRP) into natural rubber and silicone rubber. The optimum loading amounts of MRP was 30 vol.% and the natural rubber based MRE (NR-MRE) showed better mechanical property than that of silicone rubber based MRE (S-MRE). However, the modulus shift ratio caused by S-MRE, measured by Self-modified Electromagnet Applied Fast Fourier Transform Analyser (SEFFTA), was higher than that of NR-MRE. The modulus shift ratio caused by NR-MRE was 10%, while the modulus shift ratio caused by S-MRE was 35.7%. The modulus shift ratio could be improved by orienting the magnetic direction of MRP before crosslinking the MRE. The degree of orientation of MRP was analyzed using SEM.

포플러의 休眠枝 不定芽 誘導法을 이용한 GUS 遺傳子의 器外 形質轉換

정경호(Kyung Ho Chung),김주학(Joo Hak Kim),전영우(Young Woo Chun) 한국육종학회 1994 한국육종학회지 Vol.26 No.2

We have developed the in vivo transformation method for Populus species without applications of in vitro tissue culture techniques. To induce sufficient number of adventitious shoots from dormant scions which were harvested from stool beds, several factors were tested : the length of scion, three different diameters of scion, three different wounding treatments on scion, presence or absence of axillary buds, cutting orientation. The best condition for adventitious shoot production was the scion without axillary buds, 25㎝ in length, 10-15㎜ in diameter with crooked cuts. Average 130 shoots were regenerated from the cut surface of one-year-old scion. Shoots were regenerated from callus-like structure originally induced from cambium of cut surface. A binary vector plasmid, pBI121, was used containing 2 chimeric gene constructs : 1) Nopaline synthase(nos) promoter-NPTⅡ-nos terminator and 2) CaMV 35S promoter-β-glucuronidase(GUS)-nos terminator. The binary vector was transfered to Agrobacterium tumefaciens strain A281 and C58 by triparental mating. The scions with wounding treatment were co-cultured for 24 hours with Agrobacterium binary vector systems in shaking incubator. After co-cultivation, these scions were washed and cultured on waterbeds. Following 14 days of culture in growth chamber, the regenerants from the co-cultivated scions were tested GUS assay to confirm the expression GUS gene. About 30% of regenerants were confirmed as transgenic poplar by the GUS activity in stems and leaves.

수용액에서의 소수성실리카를 이용한 스티렌/부틸메타크릴레이트 입자 및 카본블랙을 함유한 복합체 입자의 합성

정경호 ( Kyung Ho Chung ),박문수 ( Moon Soo Park ) 한국고무학회 2012 엘라스토머 및 콤포지트 Vol.47 No.1

물을 반응매체로 하고 스티렌과 부틸메타크릴레이트 (BMA)를 단량체로 하여 65℃에서 95℃ 사이의 선택된온도에서 현탁중합을 실시하였다. 소수성 실리카를 안정제로, azobisisobutyronirile (AIBN)을 개시제로 선택하였다. 안정제의 최적 분산은 pH 10에서 이루어졌으며 반응은 pH 7에서 진행하였다. TGA 및 EDS 측정으로 사용한 실리카의 90%는 안정제로 10%는 입자 내로 유입되는 것으로 분석되었다. 안정제의 농도가 증가할수록 평균입경은 감소하였다. 분자량은 안정제의 농도가 1.67 wt%에 이르며 증가하였다. 개시제의 농도 및/혹은 반응온도의 상승에 따라 반응속도는 증가하였으나 분자량은 감소하였다. 입자의 입경은 개시제의 농도 및 반응온도에 거의 무관하였다. BMA의 비가 증가하면서 유리전이온도는 감소하였으며 불규칙한 형상의 입자가 증가하였다. 카본블랙을 함유하는 스티렌/BMA의 중합반응은 반응완료에 보다 많은 시간이 소요되었다. 소수성 실리카를 안정제로 하는 현탁중합반응을 이용하여 카본블랙을 함유하는 평균입경이 1-30 ㎛의 구형 폴리(스티렌-BMA) 공중합체 복합체 입자를 합성할 수 있다는 사실을 확인하였다. A suspension copolymerization of styrene and butyl methacrylate (BMA) in the aqueous phase was conducted at a selected temperature between 65 and 95 ℃. Hydrophobic silica was selected as a stabilizer and azobisisobutyronitrile (AIBN) as an initiator. Optimum dispersion of silica in water was obtained at pH 10 while polymerization reaction was run at pH 7. TGA and EDS measurements revealed that 90% of silica functioned as a stabilizer and 10% were incorporated into polymeric particles. Average particle diameter decreased with increasing amounts of stabilizer. Molecular weights displayed an increase when the stabilizer concentration reached 1.67 wt%. An increase in the initiator concentration and/or reaction temperature raised the reaction rate but decreased molecular weights. Particle diameter was nearly independent of the initiator concentration and reaction temperature. An increase in the BMA proportion decreased the glass transition temperature and increased the particle diameter with irregularity in shape. Incorporation of carbon black into the particles composed of styrene and BMA prolonged the reaction time before reaching completion. We have confirmed that a suspension copolymerization of styrene and BMA with hydrophobic silica as a stabilizer can produce spherical composite particles with 1-30 ㎛ in diameter containing carbon black.