• 디지털콘텐츠학회 논문지
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• 제12권2호
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• pp.241-252
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• 2011

운영체제의 다른 부분이나 저장장치, 매체의 변화에 비해 파일시스템은 지난 수십 년 간 그 발전 속도가 더딘 편이다. 그러나 데이터의 증가에 따라 파일의 개수는 기하급수적으로 증가하고 있으며, 이렇게 늘어난 파일들에 대해 검색을 효율적으로 수행하기 위한 새로운 파일시스템 구조에 대한 연구가 최근 파일에 대한 시맨틱 검색을 하고자 하는 요구와 맞물려 주목 받고 있다. 하지만 이러한 연구는 저장 장치와 바로 맞닿는 계층이 아닌 더 상위 계층에서만 이루어지고 있어 기존의 하드디스크와는 다른 특성을 지니는 플래시 메모리 기반의 저장장치인 SSD에 최적화를 시키기 위한 노력으로 이어지진 않았다. 논문에서는 다중 로깅 지점이라는 SSD의 특성을 활용한 로그기반 파일시스템이 SSD에서 얻는 성능상의 이점을 활용하여 새로운 요구사항인 시맨틱 파일 검색까지 추가 비용 없이 지원하는 파일시스템을 제안한다.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2009년도 학술대회
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• pp.84-89
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• 2009

핸드폰, PMP, MP3 플레이어 등으로 대표되는 개인 모바일 장치는 빠르게 발전하고 있다. 이런 모바일 환경의 발전은 사용자의 일상을 이해하고자 하는 라이프로그 연구를 활성화하고 있다. 즉, 모바일 장치의 다양한 센서들을 활용하여 개인의 일상을 기록한 라이프로그는 복잡한 일상에 대한 기억 보조 도구로 사용가능하기에 현재 활발히 연구되고 있다. 본 논문에서는 GPS에 의한 실외 위치뿐만 아니라 무선랜에 의한 실내 위치를 고려하여 상황을 추론하고 시각화하는 방법을 제시한다. 실내에서 GPS가 제대로 동작하지 않더라도 무선랜을 기반으로 한 실내 위치 추정을 통해 위치 정보를 획득하고 상황 인식 성능을 향상시켰다. 또한, 지도 인터페이스 및 블로그를 기반으로 하는 시각화 방법을 개발하였다. 실험에서는 모바일 장비를 가지고 실제 데이터를 수집한 뒤 제안하는 방법을 통해 상황을 인식하고 시각화 서비스를 제공하는 성능을 평가하였다.

• Food Quality and Culture
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• 제2권1호
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• pp.55-60
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• 2008

This study examined the effects of lactic acid spray, hot water spray, or their combined treatment, as well as the effects of acidified sodium chlorite (ASC), for the decontamination of Escherichia coli on beef carcass surfaces using a commercial intervention system. With this system, the effects of 2 or 4% lactic acid (v/v), hot water ($89{\pm}1^{\circ}C$), or their combined treatment, were examined in terms of reducing inoculated E. coli. ASC (266 ppm), which was adjusted to pH 2.5 using acetic acid or citric acid, was applied using a hand-held spray system. When the beef carcasses were treated with 2 or 4% lactic acid for 10.4 s, less than 1 log reductions of inoculated E. coli were observed. A hot water spray treatment for 9.8 s resulted in a 2.1 log reduction of inoculated E. coli. However, when the hot water was followed with either 2 or 4% lactic acid, no difference in E. coli reduction was found between the hot water alone or the combined treatment with lactic acid. When ASC was adjusted to pH 2.5 with acetic acid and citric acid, 3.8 and 4.1 log reductions of E. coli were observed, respectively. Overall, the lactic acid spray treatment was least effective, and the ASC treatment was most effective, for the E. coli decontamination of beef carcasses. Therefore, these data suggest that ASC would be a more effective intervention against E. coli than most of the methods currently being used. However, more research is required to evaluate the effects of ASC on other organisms, as well as to identify application methods that will not affect meat quality.

• 한국환경과학회지
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• 제19권7호
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• pp.849-860
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• 2010

A new $N_3O_2$ pentadentate ligand, N,N'-Bis(2-hydroxybenzyl)-ethylenetriamine(H-BHET 3HCl) was synthesized. The hydrochloric acid salts of Br-BHET 3HCl, Cl-BHET 3HCl, $CH_3O$-BHET 3HCl and $CH_3$-BHET 3HCl containing Br-, Cl-, H-, $CH_3O-$ and $CH_3-$ groups at the para-site of the phenol group of the H-BHEP were synthesized. The structures of the ligands were confirmed by C. H. N. atomic analysis and $^1H$ NMR, $^{13}C$ NMR, UV-visible and mass spectra. The calculated stepwise protonation constants(${\logK_n}^H$) of the synthesized $N_3O_2$ ligands showed six steps of the proton dissociation. The orders of the overall protonation constants($\log{\beta}_p$) of the ligands were Br-BHET < Cl-BHET < H-BHET < $CH_3O$-BHET < $CH_3$-BHET. The orders agreed well with that of para Hammett substituent constants(${\delta}_p$). The calculated stability constants($\logK_{ML}$) between the ligands and heavy metal ions (Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Pb(II)) agreed well with the order of the overall proton dissociation constants of the ligands but they showed a reverse order in para Hammestt substituent constants(${\delta}_p$). The order of the stability constants between the heavy metal ions with the synthesized ligands were Co(II) < Ni(II) < Cu(II) > Zn(II) > Cd(II) > Pb(II).

• 한국CDE학회논문집
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• 제18권1호
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• pp.21-27
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• 2013

Presented in the paper is a log data based modeling method for effective construction of a virtual plant model which can be used for the virtual PLC (Programmable Logic Controller) simulation. For the PLC simulation, the corresponding virtual plant, consisting of virtual devices, is required to interact with the input and output symbols of a PLC. In other words, the behavior of a virtual device should be the same as that of the real device. Conventionally, the DEVS (Discrete Event Systems Specifications) formalism has been used to represent the behavior a virtual device. The modeling using DEVS formalism, however, requires in-depth knowledge in the simulation area, as well as the significant amount of time and efforts. One of the key ideas of the proposed method is to generate a plant model based on the log data obtained from the production system. The proposed method is very intuitive, and it can be used to generate the full behavior model of a virtual device. The proposed approach was applied to an AGV (Automated Guided Vehicle).

• 한국버섯학회지
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• 제5권3_4호
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• pp.91-97
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• 2007

Shiitake mushroom (Lentinula edodes) is usually cultivated on the oak log. Log cultivation of this mushroom is getting difficult to get oak logs and has a weak point of its long cultivation period. Recently sawdust cultivation is getting increase. It is important to make mycelia browning on the substrate surface. This browned surface in sawdust cultivation plays an important role like as artificial bark of the oak log, which protects the other pests and suppresses water evaporation in the substrate. The period for mycelia browning is so long that the sawdust cultivation of Shiitake mushroom can not spread well into the mushroom farms. The development of methods for the rapid mycelia browning is quite required. In this article we would like to discuss about the enzymatic activities related mycelia browning and search the methods of cultivation period reduction.

• 지식경영연구
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• 제9권3호
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• pp.21-42
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• 2008

As many companies have recognized the importance of Knowledge Management(KM), they have invested lots of their resources in developing and deploying Knowledge Management Systems(KMS) to organize and share knowledge. When they implemented KMS in their organizations, most of them had high expectations about KMS at tile beginning. However, as time passed, its usage was rapidly declined. There have been many attempts to increase its usage. Many research works have tried to find solutions from users and organizations viewpoints, instead of the actual usage data itself. In order to assess the usage level of KMS, they have normally utilized user's attitudes toward KMS by assuming that user attitudes have strong relationship with actual uses of KMS. The purpose of this study is to assess tile impacts of user, organizational, and job characteristics on the satisfaction and the usage levels of KMS. Unlike other studies, this study is to explore impact factors which affect the usage level of KMS in organizations by using actual KMS log data as well as user's attitudes.

• Bulletin of the Korean Chemical Society
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• 제14권6호
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• pp.726-732
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• 1993

A comparative study on cadmium(II) complexation with three well characterized humic acids (SHA: soil humic acid from the Okchun Metamorphic Belt; AqHA: aquatic humic acid from Gorleben underground aquifer, Germany; CoHA: commercially available humic acid from the Aldrich Co.) was carried out in 0.1 M $NaClO_4$ at different solution pH(5.0, 5.5, and 6.0) using the ultrafiltration technique. The maximum binding ability (MBA) of the humic acids for cadmium(II) was observed to vary with their origins and solution pH. The results suggest that 1 : 1 complex predominates within the experimental range, and the conditional stability constants were calculated based on the assumption of cooperative binding, yielding log K values that were quite similar (CoHA: 4.17${\pm}$0.08; AqHA: 4.14${\pm}$0.07; SHA: $4.06{\pm} 0.12\;l\;mol^{-1}$ at pH 6.0) irrespective of humic acid origins or pH. By contrast a nonlinear Schatchard plot was obtained, using the cadmium(II) ion selective electrode speciation analysis method, which indicated that humic acid may have two or more classes of binding sites, with $log\;K_1\;and\;log\;K_2$ of 4.73${\pm}$ 0.08 and $3.31{\pm}0.14\;l\;mol^{-1}$ respectively.

• 한국입자에어로졸학회지
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• 제19권4호
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• pp.145-154
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• 2023

Granular bed filters are widely used to remove particulate matter in flue gas and are filled with various shapes of packing material. The packing material plays an important role in determining the overall collection performance, such as pressure drop and collection efficiency. The pressure drop of a granular bed filter has been calculated using the Ergun equation, while the collection efficiency has been predicted using the log-penetration equation based on the single sphere theory. However, a prediction equation of collection efficiency for a granular bed filter filled with non-spherical packing materials has not been suggested yet. Therefore, in this study, three different shapes of packing materials (sphere, cylinder, and irregular) were prepared to propose a prediction equation. The pressure drop and collection efficiency in a granular bed filter filled with each shape of packing material were measured experimentally and compared with theoretically predicted values. We found that experimentally measured pressure drops matched well with values theoretically predicted using the Ergun equation considering the shape factor. However, experimental collection efficiencies were higher than theoretical ones predicted by the log-penetration equation using the single sphere theory. We modified the log-penetration equation by employing a shape factor and found a good relationship between experimental and theoretical collection efficiencies.

• 정보보호학회논문지
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• 제34권4호
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• pp.587-596
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• 2024

사이버 공격, 위협이 복잡해지고 빠르게 진화하면서, 4차 산업 혁명의 핵심 기술인 인공지능(AI)을 이용하여 사이버 위협 탐지 시스템 구축이 계속해서 주목받고 있다. 특히, 기업 및 정부 조직의 보안 운영 센터(Security Operations Center)에서는 보안 오케스트레이션, 자동화, 대응을 뜻하는 SOAR(Security Orchestration, Automation and Response) 솔루션 구현을 위해 AI를 활용하는 사례가 증가하고 있으며, 이는 향후 예견되는 근거를 바탕으로 한 지식인 사이버 위협 인텔리전스(Cyber Threat Intelligence, CTI) 구축 및 공유를 목적으로 한다. 본 논문에서는 네트워크 트래픽, 웹 방화벽(WAF) 로그 데이터를 대상으로 한 사이버 위협 탐지 기술 동향을 소개하고, TF-IDF(Term Frequency-Inverse Document Frequency) 기술과 자동화된 머신러닝(AutoML)을 이용하여 웹 트래픽 로그 공격 유형을 분류하는 방법을 제시한다.