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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.
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 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.
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.
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.
정경호(Kyung-Ho Chung),금유환(Yu-Hwan Kuem),이성준(Seong-Joon Lee),안광선(Gwang-Sun Ahn) 한국정보과학회 2002 한국정보과학회 학술발표논문집 Vol.29 No.1A
최근 네트워크 고속화로 인한 무선 정보전송의 이용이 다양해져 이동국과 이동전화 교환기간 문제가 생긴 중계기를 발견할 수 있다. 이러한 문제 발생시 문제 사항들을 감시하여 적절한 조치를 취할 수 있도록 도와주는 모니터링 시스템이 요구된다. 본 논문에서는 중계기에 리눅스 임베디드 운영체제를 장치한 장비를 통해 네트워크 관리 프로토콜인 SNMP를 이용하여 중계기 사항을 감시하고 CDMA의 단문 메시지 서비스를 통해 관리자와 중계기간에 정보를 네트워크 상으로 전달될 수 있도록 설계하였다. 이에 중계기상의 SNMP 데이터 패킷을 CDMA 방식의 SMS로 변환하여 관리자의 시스템으로 메시지를 전달하는 모니터링 시스템 설계를 제안한다.
Nodule 배양방법을 이용한 잡종포플러의 식물체 재분화
정경호(Kyung Ho Chung),전영우(Young Woo Chun) 한국산림과학회 1991 한국산림과학회지 Vol.80 No.1
Developmental micropropagation method and somatic embryogenesis for hybrid poplars, Populns ehrarnericana Eco28, P. nigra X P. moximowiczii 62-9, were established using nodule culture system. Calli of Eco28 and 62-9 clone were initiated from leaf explant on the medium with 0.5㎎/ℓ and 2.0㎎/ℓ 2, 4-D, respectively. Cell suspension culture was established from callus derived from leaf explant culture. When suspended on MS medium with optimal combination of BA and NAA fine nodules were obtained after 2 weeks of culture. For shoot regeneration, nodules were transferred into liquid and agar solidified medium. Numerous shoots were regenerated from nodules of 62-9 on liquid media. Organogenesis was effectively achieved on agar solidified regeneration media containing different concentrations of BA and adenine sulfate. Average numbers of 27 and 24 shoots per nodule were induced from 62-1 and Eco28 clones after 8 weeks of culture, respectively. In addition, somatic embryogenesis also occurred in the same regeneration medium. This procedure can be applied to vegetative propagation, utilization of somaclonal variation, production of secondary metabolite and materials of biotechnology research.