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SSD 스토리지 시스템에서 PRAM 캐시를 이용한 데이터 중복제거 기법
이승규,김주경,김덕환,Kim, Ju-Kyeong,Lee, Seung-Kyu,Kim, Deok-Hwan 대한전자공학회 2013 전자공학회논문지 Vol.50 No.6
In the recent cloud storage environment, the amount of SSD (Solid-State Drive) replacing with the traditional hard disk drive is increasing. Management of SSD for its space efficiency has become important since SSD provides fast IO performance due to no mechanical movement whereas it has wearable characteristics and does not provide in place update. In order to manage space efficiency of SSD, data de-duplication technique is frequently used. However, this technique occurs much overhead because it consists of data chunking, hasing and hash matching operations. In this paper, we propose new data de-duplication method using PRAM cache. The proposed method uses hierarchical hash tables and LRU(Least Recently Used) for data replacement in PRAM. First hash table in DRAM is used to store hash values of data cached in the PRAM and second hash table in PRAM is used to store hash values of data in SSD storage. The method also enhance data reliability against power failure by maintaining backup of first hash table into PRAM. Experimental results show that average writing frequency and operation time of the proposed method are 44.2% and 38.8% less than those of existing data de-depulication method, respectively, when three workloads are used. 최근 클라우드 스토리지 환경에서 전통적인 스토리지장치인 하드디스크를 대체하여 SSD(Solid-State Drive)의 사용량이 증가하고 있다. SSD는 기계적인 동작이 없어 빠른 입출력 성능을 가지는 반면 덮어쓰기가 불가능한 특성을 가지고 있어 공간 효율성을 위한 관리가 중요하다. 이와 같은 마모도 특성을 갖는 SSD의 공간 효율성을 효과적으로 관리하기 위해 데이터 중복제거 기법을 이용한다. 하지만 데이터 중복제거 기법은 데이터 청킹, 해싱, 해시값 검색과정 연산을 포함하기 때문에 오버헤드가 발생하는 문제점이 있다. 본 논문에서는 SSD 스토리지 시스템에서 PRAM 캐시를 이용한 데이터 중복제거 기법을 제안한다. 제안한 방법은 DRAM의 1차 해시테이블에 PRAM에 캐싱된 데이터를 위한 해시값들을 저장하고, LRU(Least Recently Used)기법을 이용하여 관리한다. PRAM의 2차 해시테이블에는 SSD 스토리지에 저장된 데이터에 대한 해시값들을 저장하고, DRAM의 1차 해시테이블에 대한 백업을 PRAM에 유지함으로써 전원 손실등에 대비하여 신뢰성을 향상시킬 수 있다. 실험결과, 제안하는 기법은 기존의 DRAM에 모든 해시값들을 저장하여 관리하는 기법보다 SSD의 쓰기 횟수 및 연산시간을 워크로드별 평균 44.2%, 38.8%의 감소 효과를 보였다.
이승규,신정우,김태욱,Lee, Seung-Gyu,Shin, Jeong-Woo,Kim, Tae-Uk 한국항공운항학회 2015 한국항공운항학회지 Vol.23 No.1
Because of kinematic complexities, nonlinear behavior, etc, the performance of oleo-pneumatic landing gear is predicted by qualified commercial softwares. While commercial softwares predict more exactly, it takes a long time to construct or modify a model. At initial design stage, design parameters can be determined quickly and exactly enough with simple 2 degree of freedom model of mass, spring and damping. 2 degree of freedom model can be easily applied to optimization and reliability analysis which takes repetitive computation. In this paper, oleo-pneumatic landing gear is modeled as a nonlinear 2 degree of freedom model. The analysis are compared with landing gear drop test. To determine design parameter, optimization problem is solved with genetic algorithm and 2 degree of freedom model.
급동형태(扱胴形態)와 작물(作物)의 수분함량(水分含量)이 맥주보리의 탈곡성능(??性能)에 미치는 영향(影響)
이승규,김성태,민영봉,Lee, Seung Kyu,Kim, Sung Tae,Min, Young Bong 한국농업기계학회 1983 바이오시스템공학 Vol.7 No.2
The purpose of this experiment was to evaluate the effect of the drum structures and crop moisture contents on the performance of newly developed throw-in type axial thersher. Sachun No.2 malting barley with four different crop moisture levels was used as the testing material. Four different types of threshing drum; the cylindrical drum-equipped with teeth or rubber bars and the conical drum-equipped with teeth or rubber bars were tested. The results are summarized as follows; 1. The threshing efficiency of cylindrical drum was higher than that of the conical one, and the drum with teeth was more effective in threshing than the one with bars. However, the higher the threshing efficiency over the whole range of moisture levels and drum speeds given, the more the rapid and unexpectable variations in threshing efficiencies 2. The separation efficiency of the conical drum was decreased as drum speed was increased and was not so much influenced as crop moisture content. But in case of the cylindrical drum, the result was shown in opposite way to that of the conical one. The separation efficiency of the drum with teeth was higher than that of the drum with bars and no significant decrease in separating efficiency was found at wet crop condition. 3. Foreign matters other than grain passing through the concave sieve was decreased as crop moisture content was increased, and the purity was increased at middle range of drum speed regardless of drum types. 4. Minimum grain loss was found at 700 rpm to 800 rpm of drum speed for all types of drums. The effect of crop moisture content on total grain loss was varied with drum types. As far as the grain loss is concerned, the conical drum having teeth was not so greatly influenced by various crop moisture contents and drum speeds as compared with the other types of drum. 5. Generally, the crop moisture content has more relevant effect on the germination than the drum speed regardless of drum types. The germination percentage of grain threshed by the conical drum and the bar attached drum were higher than those of cylindrical one and teeth attached one, respectively.
김치에서 분리한 Lactobacillus plantarum LHC52의 항균활성과 요구르트의 관능성 연구
이승규,한기성,정석근,오미화,장애라,김동훈,배인휴,함준상,Lee, Seung-Gyu,Han, Ki-Sung,Jeong, Seok-Geun,Oh, Mi-Hwa,Jang, Ae-Ra,Kim, Dong-Hun,Bae, In-Hyu,Ham, Jun-Sang 한국축산식품학회 2010 한국축산식품학회지 Vol.30 No.2
The aim of our study was to develop a new starter culture for fermented milk. Polymerase chain reaction screening of 103 acid-producing isolates from Kimchi identified 72 Lactobacillus strains. The ability of the strains to inhibit the growth of the food-borne human pathogens (Escherichia coli, Salmonella Enteritidis, Staphylococcus aureus) was measured, using a conventional paper disk method. Among the 72 strains, strain LHC52 displayed potent antagonistic activity. Use of 16S rDNA sequencing and the API 50CHL system identified the strain as Lactobacillus plantarum and it was designated L. plantarum LHC52. Biochemical analyses revealed especially high antibacterial activity against E. coli. Yogurt produced using L. plantarum LHC52 did not show different microbiological and physicochemical properties compared to conventionally-prepared yogurt, implicating L. plantarum LHC52 as a useful, potently antibacterial starter culture for yogurt preparation.
이승규,김윤호,Lee, Seung-Gyu,Kim, Yoon-Ho Korean Society of Applied Entomology 2020 한국응용곤충학회지 Vol.59 No.2
한국산 미기록 종인 네무늬구멍썩덩벌레붙이(Lissodema plagiatum Lewis) (신칭)를 한반도에서 처음으로 보고하고, Lissodema laevipennis Marseul의 한국 기록을 삭제한다. 한국산 썩덩벌레붙이과에 대한 종 검색표와 미기록 종에 대한 사진과 분류학적 의견을 제시한다. Lissodema plagiatum Lewis is newly recorded and L. laevipennis Marseul is removed from the Korean fauna. A habitus photograph and taxonomic note of the newly recorded species are provided, with a key to Korea species of the family Salpingidae Leach.
이승규,김민경,이연정,정석근,오미화,김동훈,박광욱,이완규,함준상,Lee, Seung-Gyu,Kim, Min-Kyung,Lee, Yeon-Jeong,Jeong, Seok-Geun,Oh, Mi-Hwa,Kim, Dong-Hun,Park, Kwang-Wook,Lee, Wan-Kyu,Ham, Jun-Sang 한국축산식품학회 2010 한국축산식품학회지 Vol.30 No.1
산양유의 체세포수는 측정방법에 따라 많은 차이가 보고되고 있으나 국제적인 표준방법으로 pyronin Y-methyl green stain에 의한 직접현미경법이 사용되고 있다. 8개 목장 총 48개 시료를 pyronin Y-methyl green stain에 의한 직접검경법, 국립축산과학원에서 보유중인 ADAM-SCC, 충청북도 축산위생연구소에서 보유중인 Somacount 500으로 측정하여 결과를 비교하였다. Pyronin Y-methyl green stain 측정시 전체 평균은 $7.3{\times}10^5$ cells/mL인 반면 ADAMSCC와 Somacaount 500은 각각 $4.9{\times}10^5$과 $11.6{\times}10^5$ cells/mL로 나타나 과소 또는 과대평가되는 결과를 보였다. 직접현미경법과 ADAM-SCC또는 Somacaount 500과의 상관계수는 각각 0.0332 또는 0.2285로 매우 낮으며 장비간의 상관계수도 0.1552로 매우 낮게 나타났다. 산양유의 체세 포수 저감을 위해서는 측정장비의 개발이 필요하며 장비를 표준화하기 위한 표준측정법으로 pyronin Y-methyl green stain의 채택이 필요하다.
원격 수신함수를 이용한 서울과 인천 관측소 하부의 지각 속도구조와 Moho 불연속면 특성 연구
이승규,김소구,Lee, Seoung Kyu,Kim, So Gu 대한자원환경지질학회 1998 자원환경지질 Vol.31 No.4
The purpose of this study is to find P-wave crustal velocity structure and the Moho characteristics beneath Seoul (SEO) and Inchon (INCN) stations using broadband teleseismic records. The use of broadband receiver function analysis is increasing to estimate the fine-scale velocity structure of the lithosphere. The broadband receiver functions are developed from teleseismic events of P waveforms recorded at Seoul (SEO) and Inchon (INCN) stations, and are analyzed to examine the crustal structure beneath the stations. The teleseismic receiver functions are inverted in the time domain of the vertical P wave velocity structures beneath the stations. The crustal velocity structures beneath the stations are estimated using the receiver function inversion method (Ammon et al., 1990). The general features of inversion results are as follows: (1) For the Seoul station, the Conrad and Moho discontinuities exist at 22 km and 30 km depth in the south ($BAZ=180^{\circ}$) direction. (2) For the Inchon station, the Conrad discontinuity exists at 22 km depth in the direction of SE ($BAZ=145^{\circ}$) and the Moho discontinuity exists at 30~34 km depth with a 4 km thick, which consists of a laminated velocity transition layers with thickness, whereas a crust-mantle boundary beneath the Seoul station consists of a more sharp boundary compared with the Moho shape of INCN station.