• Journal of KIISE:Computer Systems and Theory
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• v.34 no.11
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• pp.599-609
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• 2007

Due to the restrictions of Flash memory such as overwrite limitation and write/erase operational unit differences, block cleaning is required in Flash memory based file systems and known as a key factor on the performance of file systems. In this paper, we identify three parameters, namely utilization, invalidity and uniformity, and analyze how the parameters affect the cost of block cleaning. The analysis show that as uniformity degrades, the cost of block cleaning increases drastically. To overcome this problem, we design a new modification-aware(MODA) page allocation scheme that strives to keep uniformity high by separating frequently-updating data from infrequently-updating data. Real implementation experiments conducted on an embedded system show that the MODA scheme can actually enhance uniformity of Flash memory, which consequently leads to reduce the cost of block cleaning with an average of 123%, compared to the traditional sequential allocation scheme that is used in YAFFS.

• Journal of Korean Society of Steel Construction
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• v.18 no.2
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• pp.203-211
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• 2006

This paper presents a new, effective torsional constant for thin-waled open beams under concentrated and uniformly distributed torques. The proposed constant can be used directly, instead of the St. Venant torsional constant, for any generic comemrcial finite-element program, without modifying the algorithm. The derived torsional constant accounts for both the pure torsion and the warping torsion, and is equal to the St. Venant torsion constant times a correction factor. It is also shown, in the case of the St. Venant torsion, that the derived constant is identical to the torsional constant. The derived effective torsional constant is different from the one given by Elhelbawey et al. The pure torsional shear stress, the warping shear stress, and the warping normal stress were also determine d, using the maximum twisting angle. The accuracy of the proposed torsional constant was validated by comparing the numerical results with the closed-form solutions or other numerical results available in the literature.

• Journal of the Korean Data Analysis Society
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• v.20 no.6
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• pp.2865-2872
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• 2018

In the field of data mining technique, there are various methods such as association rules, cluster analysis, decision tree, neural network. Among them, association rules are defined by using various association evaluation criteria such as support, confidence, and lift. Agrawal et al. (1993) first proposed this association rule, and since then research has been conducted by many scholars. Recently, studies related to crossover entropy have been published (Park, 2016b). In this paper, we proposed a purely symmetric J measure considering directionality and purity in the previously published J measure, and examined its usefulness by using examples. As a result, it is found that the pure symmetric J measure changes more clearly than the conventional J measure, the symmetric J measure, and the pure crossover entropy measure as the frequency of coincidence increases. The variation of the pure symmetric J measure was also larger depending on the magnitude of the inconsistency, and the presence or absence of the association was more clearly understood.

• Korean Journal of Food Science and Technology
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• v.35 no.4
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• pp.648-652
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• 2003

Precise and rapid method out for distinguishing blended sesame oils through the electronic nose analysis was developed. Sesame oil was blended with corn oil at the ratio of 95 : 5, 90: 10, and 80 : 20 (w/w), respectively. Samples were then analyzed by gas chromatography, SPME-GC/MS, and the electronic nose composed of 12 different metal oxide sensors. Sensitivities $(delta\;R_{gas}/R_{air})$ of sensors from electronic nose were analyzed by principal component analysis (PCA). Proportion of the first principal component was 98.76%.

• Journal of the Korean Data and Information Science Society
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• v.22 no.2
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• pp.179-188
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• 2011

Association rule represents the relationship between items in a massive database by quantifying their relationship, and is used most frequently in data mining techniques. In general, association rule technique generates the rule, 'If A, then B.', whereas negative association rule technique generates the rule, 'If A, then not B.', or 'If not A, then B.'. We can determine whether we promote other products in addition to promote its products only if we add negative association rules to existing association rules. In this paper, we proposed the negatively pure association rules by negatively pure support, negatively pure confidence, and negatively pure lift to overcome the problems faced by negative association rule technique. In checking the usefulness of this technique through numerical examples, we could find the direction of association by the sign of the negatively pure association rule measure.

• KLA journal
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• v.35 no.3 s.286
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• pp.4-74
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• 1994

• The Pure and Applied Mathematics
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• v.10 no.5
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• pp.5-53
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• 2003

• Environmental and Resource Economics Review
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• v.20 no.4
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• pp.735-760
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• 2011

This study examines the effect of pollution abatement cost on net export of Korea's manufacturing industries based on Heckscher-Ohlin model. We used the panel data on manufacturing industries for 1993~2007. The main findings are as follows. First, it was found that the pollution abatement cost had a significant negative effect on net export of Korea's manufacturing industries. In particular, the effect was stood out after 1997 IMF crisis. Second,skill labor was found to be very important in determining trade pattern among variables related to factor intensities.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10e
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• pp.463-465
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• 2002

최근 인터넷의 급속한 성장과 초고속 통신망의 구축으로 인하여 다양한 멀티미디어서비스들이 제공되고 있다. 그러나 현재 대부분의 멀티미디어 서비스들은 클라이언트／서버모델을 기반으로 구축되어 있기 때문에, 중앙 서버로의 과도한 부하가 집중되는 문제점을 가지고 있다. 본 논문에서는 순수 P2P(Pure Peer-to-Peer) 환경으로 구축된 멀티미디어 서비스에서의 자원 검색 기법을 제안한다. 제안 기법은 자율성과 이동성을 지닌 이동 에이전트(mobile agent)를 기반으로 자원의 검색을 수행하여, 기존의 순수 P2P 환경에서의 검색 기법의 문제점을 해결한다. 또한, 시나리오를 통하여 제안 기법의 구체적인 동작 과정에 대해 알아본다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10a
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• pp.322-324
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• 2004

보안 시스템은 암호화 기능을 필요로 하고 암호화를 위 한 비밀키로 난수를 사용한다 난수 발생기에는 순수 난수 발생기와 의사 난수 발생기가 있다. 본 논문에서는 펜티엄부터 인텔 프로세서들이 가지고 있는 타임스탬프 카운터 레지스터(TSC MSR)에서 시드를 가져와 비트 가공을 통해 난수를 발생하는 난수 발생기를 구현하였다. 구현된 난수 발생기의 난수 품질을 평가하기 위해 순수 난수 발생기, 의사 난수 발생기의 난수 시퀀스와 비교하였다. 구현된 난수 발생기가 생성한 난수 시퀀스는 순수 난수 발생기의 난수 시퀀스와 큰 차이가 없고 특정 디바이스 없이 응용이 간단하다는 점에서 보안 시스템의 암호화키로 사용하기에 적합하다.