• Composites Research
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• 제13권3호
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• pp.30-37
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• 2000

계면상 조건과 단섬유 함유량 증가에 따른 강화고무의 동적 특성에 대해 실험적 고찰을 하였다. 손실계수는 대체적으로 섬유 함유량 증가에 따라 감소하였고 계면상 조건에 따라 다른 경향을 보였다. 계면 조건이 우수할수록 손실탄성율, $E_2$ 는 낮게 나타났다. 또한 동배율은 섬유 함유량 증가에 따라 감소하였고, 계면상 조건이 우수할수록 크게 감소하였다. 따라서 단섬유 강화고무는 진동수비가 $\sqrt{2}$이상에서 더 큰 진동절연 효과가 있다고 할 수 있다. 손실계수와 동배률의 관계로부터, 자동차의 엔진과 차체의 진동을 절연하는 부품인 Engine Mount Rubber의 적용가능성을 검토하였다.

• 한국식품영양과학회지
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• 제46권5호
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• pp.653-658
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• 2017

본 연구에서는 동적광산란법을 이용하여 아밀로즈 함량과 용매 조건에 따른 전분 분자 구조 변화를 규명하였다. 분자량이 다른 여러 가지 덱스트란 표준물질을 이용하여 동적광산란법의 정확성을 검증하였으며, 이를 전분에 적용해본 결과 아밀로즈 함량에 따른 전분 분자의 $D_h$ 변화를 규명할 수 있었고 아밀로즈 함량이 높아질수록 전분 분자의 $D_h$ 값이 증가하였다. 또한, 용매 조건에 따른 전분 분자의 $D_h$ 변화를 동적광산란법으로 규명할 수 있었으며, NaCl의 경우 농도가 높아질수록 아밀로펙틴의 $D_h$가 증가했지만, 아밀로즈의 $D_h$는 urea에 더 큰 영향을 받는 것으로 생각된다. 1-Butanol의 경우 전분 분자의 $D_h$를 증가시켰지만 주목할 만한 경향은 관찰하지 못하였다. 또한, 전분의 아밀로즈 함량과 전분 분자의 $D_h$는 유의적인 상관관계를 보였으며, 이를 활용할 경우 전분의 아밀로즈 함량을 예측하는 데 도움이 될 수 있을 것이라고 기대한다.

• ETRI Journal
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• 제39권5호
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• pp.695-706
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• 2017

This paper presents a caching algorithm that offers better reconstructed data quality to the requesters than a probabilistic caching scheme while maintaining comparable network performance. It decides whether an incoming data packet must be cached based on the dynamic caching probability, which is adjusted according to the priorities of content carried by the data packet, the uncertainty of content popularities, and the records of cache events in the router. The adaptation of caching probability depends on the priorities of content, the multiplication factor adaptation, and the addition factor adaptation. The multiplication factor adaptation is computed from an instantaneous cache-hit ratio, whereas the addition factor adaptation relies on a multiplication factor, popularities of requested contents, a cache-hit ratio, and a cache-miss ratio. We evaluate the performance of the caching algorithm by comparing it with previous caching schemes in network simulation. The simulation results indicate that our proposed caching algorithm surpasses previous schemes in terms of data quality and is comparable in terms of network performance.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.919-922
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• 1998

A content-base search method is required for video which has an unformatted and huge size of data. The index techniue is necessary for the content-based search of the video data. The first step of the video indexing is a cut detection. We propose a dynamic threshold method which change a threshold value during the cut detection process. We demonstrate that the proposed method is more efficient than the existing methods.

• Journal of Biosystems Engineering
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• 제17권1호
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• pp.79-90
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• 1992

Viscoelastic characteristics of agricultural products may be determined through three basic tests ; stress relaxation, creep, and dynamic test. Considering the changeability of living materials, dynamic test in which information is derived in a relatively short time appears to be highly desirable, in which either cyclic stress or cyclic strain is imposed and the remaining quantity (strain or stress) is measured. The periodically varying stress will also result in periodically varying strain which in a viscoelastic material should theoretically be out of phase with the stress, because part of the energy subjected to sample is stored in the material as potential energy and part is dissipated as heat. This behavior results in a complex frequency-dependent compliance denoted by J($i{\omega}$). The complex compliance and therefore the storage compliance, the loss compliance, the phase angle, and percent energy loss for the sample should be obtainable with a given static viscoelastic property of the material under static load. The complex compliance of the rough rice kernel were computed from the Burger's model describing creep behavior of the material which were obtained in the previous study. Also, the effects of cyclic load and moisture content of grain on the dynamic viscoelastic behavior of the samples were analyized. The results obtained from this study were summarized as follows ; 1. The storage compliance of the rough rice kernel slightly decreased with the frequency applied but at above the frequency of 0.1 Hz it was nearly constant with the frequency, and the loss compliance of the sample very rapidly decreased with increase in the frequency on those frequency ranges. 2. It was shown that the storage compliance and the loss compliance of the sample increased with increase in grain moisture content. Effect of grain moisture content on the storage compliance of the sample was highly significant than effect of the frequency applied, but effect of the frequency on the loss compliance of the sample was more significant than effect of grain moisture content. 3. In low moisture content, the percent energy loss of Japonica-type rough rice was much higher than that of Indica-type rough rice, but, in high moisture content, vice versa.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2005년도 학술발표논문집
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• pp.128-134
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• 2005

This study was performed to evaluate the strength and durability properties of recycled concrete containing water - redispersible copolymer powder(WRP) and blast furnace slag powder(BSP) [RCWS]. Material used were cemente, recycled coarse aggregare, natural fine aggregate, water-redispersible copolymer powder, blast-furnace slag powder. Especially, Water-redispersible powder was used for blending with Inorganic binders such as cemente, gypsum and hydrated lime etc. First of all, Mixed ratio method of RCWS made Two Type. One was called type-1 which used to BSP content 5% and WRP(Water-redispersible powder) content 0%, 1%, 2%, 3%, 4%, 5%, 6%. respectively. Another was called Type-2 which used to BSP(blast furnace slag powder)content 10% and WRP(Water-redispersible powder) content 0%, 1%, 2%, 3%, 4%, 5%, 6%. respectively. According to the experimental results of (RCWS), Incase Type-2 at curing age 28days, Compressive strength, pulse velocity and dynamic modulous of elasticity were shown higher than Type-1 and The more WRP content increasing($0%{\sim}6%$) was the lower Compressive strength, Pulse velocity and Dynamic modulous of elasticity. Water absorption ratio was in the range of $3.85%\;{\sim}\;3.23%$, it was almost equal to Type-1, 2 but Increasing the WRP content($0%{\sim}6%$), The water absorption ratio is decreased.

• ETRI Journal
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• 제36권6호
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• pp.988-998
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• 2014

For memory-based big data storage, using hybrid memories consisting of both dynamic random-access memory (DRAM) and non-volatile random-access memories (NVRAMs) is a promising approach. DRAM supports low access time but consumes much energy, whereas NVRAMs have high access time but do not need energy to retain data. In this paper, we propose a new data migration method that can dynamically move data pages into the most appropriate memories to exploit their strengths and alleviate their weaknesses. We predict the access frequency values of the data pages and then measure comprehensively the gains and costs of each placement choice based on these predicted values. Next, we compute the potential benefits of all choices for each candidate page to make page migration decisions. Extensive experiments show that our method improves over the existing ones the access response time by as much as a factor of four, with similar rates of energy consumption.

• Geomechanics and Engineering
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• 제18권5호
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• pp.471-480
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• 2019

The constructions of engineering structures such as airports, highways and railway on clayey soils may create many problems. The economic losses and damages caused by these soils have led researchers to do many studies using different chemical additives for the stabilization of them. Lime is a popular additive used to stabilize the clayey soils. When the base course is stabilized by mixing with an additive, inevitable delays may occur during compaction due to reasons like insufficient workers, breakdown of compaction equipment, etc. The main purpose of this study is to research the effect of compaction delay time (7 days) on the strength, compaction, and dynamic properties of a clay soil stabilized with lime content of 0, 3, 6, 9, 12 and 15% by dry weight of soil. Compaction characteristics of these mixes were determined immediately after mixing, and after 7 days from the end of mixing process. Within this context, unconfined compressive strength (UCS) under the various curing periods (uncured, 7 and 28 days) and dynamic triaxial tests were performed on the compacted specimens. The results of UCS and dynamic triaxial tests showed that delayed compaction on the strength of the lime-stabilized clay soil were significantly effective. Especially with the lime content of 9%, the increase in the shear modulus (G) and UCS of 28 days curing were more prominent after 7 days mellowing period. Because of the complex forms of hysteresis loops caused by the lime additive, the damping ratio (D) values differed from the trends presented in the literature and showed a scattered relationship.

• Journal of the Korean Wood Science and Technology
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• 제39권6호
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• pp.538-547
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• 2011

이 연구에서는 녹차와 목재섬유를 복합한 친환경 복합보드를 건축내장재로 활용하기 위하여, 목재섬유에 대한 녹차의 배합비율을 달리한 녹차-목재섬유 복합보드를 제작하였고, 복합보드의 동적탄성률에 미치는 녹차의 배합비율 및 바인더로 사용한 접착제의 영향을 조사하였다. 녹차-목재섬유복합보드의 동적탄성률은 녹차를 넣지 않은 대조보드(control boards)의 그것보다 적었고, 녹차배합비율이 증가할수록 커지는 경향을 나타내었다. 또한, 보드제조에 사용된 바인더의 종류에 따라 동적탄성률의 차이가 나타났는데, $E_1$급의 요소수지가 $E_0$급의 요소수지보다 1.06~1.54배의 높은 값을 나타내었으며, 녹차의 배합비율이 커질수록 양자의 차이는 커지는 것이 확인되었다. 한편, 녹차-목재섬유복합보드의 동적탄성률과 휨 강도성능과는 비교적 높은 상관관계가 확인되어 일부 편차가 큰 조건을 제외하고 동적탄성률로부터 정적 휨 강도성능의 예측이 가능할 것으로 확인되었다.

• 한국콘텐츠학회논문지
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• 제10권7호
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• pp.429-437
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• 2010

최근 웹의 기술과 기능이 사용자중심의 패러다임으로 변화되면서 e-러닝의 연구와 설계에서도 학습자 참여와 지속적인 학습이 가능한 동적인 학습콘텐츠를 구성하려는 새로운 연구가 진행되고 있다. 본 논문에서는 e-러닝 2.0에 적용할 수 있도록 효율적인 학습 환경을 제공하기 위해 학습자 중심의 동적인 학습 콘텐츠 난이도 조절에 관한 연구를 기술했다. 본 논문은 학습자 중심의 콘텐츠를 제공하기 위해 DLA(Dynamic Level Adjustment)를 제안한다. 제안된 시스템은 환경의 변화에 적응력이 강한 학습콘텐츠를 조절하고 적용할 수 있는 가이드라인이 되고, 더 깊이 있는 연구가 진행될 수 있도록 목표를 두고 있다. 성능평가 결과 학습자의 다양한 학습패턴을 인지할 수 있는 동적인 학습콘텐츠 모델을 만들 수 있었다.