• The KIPS Transactions:PartA
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• v.14A no.1 s.105
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• pp.39-46
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• 2007

Recently flash memory is widely accepted as a storage devise of embedded systems for portability and performance reasons. Flash memory has many distinguishing features compared to legacy magnetic disks. Especially, a file system for flash memory usually assumes the form of log-structured file system and it employs garbage collector accordingly. Since the garbage collector can greatly affect the performance of file system, it should be designed carefully considering flash memory features. In this paper, we suggest a new garbage collector for existing JFFS2 (Journaling Flash File System II) file system. By extensive performance evaluation, we show that the proposed garbage collector achieves improved performance in terms of flash memory consumption rate, increased flash memory life time, and improved wear-leveling.

• Journal of the Korean Chemical Society
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• v.42 no.4
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• pp.443-448
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• 1998

The thermodynamic parameters for the interaction of metal ions with dibenzo-16-crown-5 and its derivatives have been determined by solution calorimetry in methanol at 25$^{\circ}C$. Thermodynamic properties of log K, ${\Delta}H$, and $T{\Delta}S$ have been determined for the complexation of metal cations by dibenzo-16-crown-5 and its derivatives. Dibenzo-16-crown-5 and its derivatives have been studied as metal cations carrier in bulk liquid membrane (BLM) and supported liquid membrane (SLM) system. $Ag^+$ has been much more transported using dibenzo-16-crown-5 derivatives as carriers and several other metal cations have been small transported using carrier in BLM and SLM system. Ligand structure, the length of side arm, donor atom, stability constant, and carrier concentration are also important parameters in the transport of cations.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.5
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• pp.15-21
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• 2009

The design of the stud shear connector of a bridge structure is mostly controlled by the fatigue resistance not by the strength, if it is followed by AASHTO LRFD Bridge Design Specification. This fatigue design code in AASHTO LRFD is based on the research work done by Slutter and Fisher in 1966. These tests seemingly underestimated the fatigue resistance of connectors because of the inherent eccentricity of the one-face test setup which results additional tension forces to the stud. In addition, the stress ranges were not plotted in the log scale, because it was not known at that time that the fatigue resistance of the welded steel structures has a linear relationship of log scales of stress range and number of loading cycles. This study evaluates the test data produced by the Slutter and Fischer, and plot the data on the proper manner. The fatigue push-out test data produced recently by many other researches all around the world are gathered and analyzed, furthermore a design curve is recommended.

• Journal of IKEEE
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• v.23 no.3
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• pp.762-767
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• 2019

The plane-wave shielding effectiveness is typically measured for horizontal and vertical polarizations using a linearly polarized antenna. However, this typical measurement method results in big evaluation fees due to very long measurement time as well as huge idle space for maintenance, these problems is more severe especially in large shielded enclosures such as EMP protection facilities to be built in indoor buildings and underground. This paper describes the design and fabrication process and results of a planar log-spiral antenna applicable to the evaluation of the electromagnetic shielding effectiveness of a large EMP protection facility. Since the proposed antenna has a circular polarization, there is no need to separately measure the horizontal and vertical polarizations. Therefore, the measurement time can be shortened by more than 1/2, and further, its small volume with a planar structure can reduce greatly idle space required for the maintenance.

• Journal of Astronomy and Space Sciences
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• v.13 no.1
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• pp.63-71
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• 1996

A total of 546 UBV photoelectric observations of AG Per was carried out from January to December in 1993 at Chungbuk National University Observatory. With our observations, UBV light curves were constructed, three minimum times of JDHel. 2449284.213, JDHel. 2449360.060, and JDHel. 2449363.192 were determined. The phase displacement of secondary minimum time $\delta$=-0.046 were determined and orbital eccentricity e=0.071 was calculated. Forty-five times of minimum light (including ours) were collected from the literature and plotted on O-C diagram. We analyzed these data and apsidal motion period of U=76.17 (years) was obtained. Using e and U for AG Per, the internal structure constant, log k2, was found to be -2.13.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.784-786
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• 2005

본 논문에서는 기존의 플래시 파일 시스템과 차별되는 빠른 복구를 위한 로그 구조를 제안한다. 로그와 메타데이터를 플래시 메모리의 특정 영역에 기록하고, 오류가 발생하게 되면 복구단계에서 이 영역만을 스캔하기 때문에 파일 시스템의 오버헤드를 줄인다. 그리고 로깅연산은 트랜잭션으로 관리되어 다른 연산에 간섭받지 않고 독립적으로 수행이 되므로 동시성을 높이고 로깅에 따른 오버헤드가 크지 않다. 따라서 로깅과 복구에 필요한 시간을 최소화하여 신뢰성 있는 파일 시스템 구성이 가능하다.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.771-774
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• 1998

In this paper proposes a new bit-parallel structure for a multiplier over GF((Pn)m), with k-nm. Mastrovito Multiplier, Karatsuba-ofman algorithm are applied to the multiplication of polynomials over GF(2n). This operation has a complexity of order O(k log p3) under certain constrains regardig k. A complete set of primitive field polynomials for composite fields is provided which perform modulo reduction with low complexity. As a result, multiplier for fields GF(Pk) with low gate counts and low delays are constructed. The architectures are highly modular and thus well suited for VLSI implementation.

• Journal of The Korean Astronomical Society
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• v.36 no.1
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• pp.13-19
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• 2003

We present a study of the old open cluster Trumpler 5 (Tr 5), based on the CDS archival data. From the color-magnitude diagrams of Tr 5, we have found the positions of main-sequence turn-off (MSTO) and red giant clump (RGC) stars. Using the mean magnitude of the RGC stars, we have estimated the reddening toward Tr 5, E(B - V) = 0.60 $\pm$ 0.10. Using the stars common in two data sets and the theoretical isochrones of Padova group, we have estimated the distance modulus $V_o - M_v = 12.64 {\pm} 0.20 (d = 3.4 {\pm} 0.3 kpc)$, the metallicity [Fe/H) = -0.30 $\pm$ 0.10, and the age of 2.4 $\pm$ 0.2 Gyr (log t = 9.38). These metallicity and distance values are consistent with the relation between the metallicity and the Galactocentric distance of other old open clusters, for which we obtain the slope of ${\Delta}[Fe/H]/ R_{gc} = -0.064 {\pm} 0.010\;dex\;kpc^{-1}$.

• Journal of Environmental Science International
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• v.8 no.3
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• pp.371-377
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• 1999

The effects of benzamidoxime concentration, solvents and temperature on the degree of metal extraction were investigated to apply benzamidoxime to heavy metal extraction as chelating agent. Benzamidoxime was synthesized from benzonitrile with hydroxylamine. The chemical structure of benzamidoxime was identified. The degree of heavy metal extraction was increased with increasing the concentration of benzamidoxime and decreasing the extraction temperature. Benzamidoxime was found to be an concentration of benzamidoxime and decreasing the extraction temperature. Benzamidoxime was found to be an effective extractant for Cu-extraction by benzene or chloroform. The relationship between the thermodynamic overall equilibrium constant and absolute temperature was expressed as log K = -5.56 ＋ $855T^{-1}$. Heat of extraction, $$\Delta$H^0$ were calculated from overall equilibrium constants at various temperature and the extraction reactionby benzamidoxime was found to be exthothermic.

• Journal of Korea Multimedia Society
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• v.13 no.12
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• pp.1760-1766
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• 2010

The linearized suffix tree (LST) is an array data structure supporting traversals on suffix trees. We apply this LST to two dimensional (2D) suffix trees and obtain a space-efficient substitution of 2D suffix trees. Given an $n{\times}n$ text matrix and an $m{\times}m$ pattern matrix over an alphabet ${\Sigma}$, our 2D-LST provides pattern matching in $O(m^2log{\mid}{\Sigma}{\mid})$ time and $O(n^2)$ space.