• The KIPS Transactions:PartD
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• v.14D no.7
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• pp.719-726
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• 2007

Recently, NAND flash memory has been used for a storage device in various mobile computing devices such as MP3 players, mobile phones and laptops because of its shock-resistant, low-power consumption, and none-volatile properties. However, due to the very distinct characteristics of flash memory, disk based systems and applications may result in severe performance degradation when directly adopting them on flash memory storage systems. Especially, when a B-tree is constructed, intensive overwrite operations may be caused by record inserting, deleting, and its reorganizing, This could result in severe performance degradation on NAND flash memory. In this paper, we propose an efficient buffer management scheme, called IBSF, which eliminates redundant index units in the index buffer and then delays the time that the index buffer is filled up. Consequently, IBSF significantly reduces the number of write operations to a flash memory when constructing a B-tree. We also show that IBSF yields a better performance on a flash memory by comparing it to the related technique called BFTL through various experiments.

• Journal of Applied Biological Chemistry
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• v.51 no.6
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• pp.272-276
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• 2008

Purification and some properties of Xylogone sphaerospora ${\beta}$-mannanase were reprevious previous paper. Locust bean gum galactomannan was hydrolyzed by the purified ${\beta}$-mannanase, and then the hydrolysates was separated by activated carbon column chromatography. The main hydrolysates were composed of D.P. (Degree of Polymerization) 4 and 6 galactosyl mannooligosaccharides. For elucidate the structure of D.P 4 and 6 galactosyl mannooligosaccharides, sequential enzymatic action was performed. D.P 4 and 6 were identified as ${Gal^2}{Man_3}\;(6^2-mono-O-{\alpha}-D-galactopyranosyl-4-O-{\beta}-D-mannotriose)$ and ${Gal^2}{Man_5}\;(6^2-mono-O-{\alpha}-D-galacto- pyranosyl-4-O-{\beta}-D-mannopentaose)$. To investigate the effects of locust bean gum galactosyl mannooligosaccharides on in vitro growth of Bifidobacterium longum, B. bifidum, B. infantis, B. adolescentis, B. animalis, B. auglutum and B. breve. Bifidobacterium spp. were cultivated individually on the modified-MRS medium containing carbon source such as D.P. 4 and D.P. 6 galactosyl mannooligosaccharides, respectively. B. longum and B. bifidum grew up to-fold and 6.6-fold more effectively by the treatment of D.P. 6 galactosyl mannooligosaccharides, compared to those of standard MRS medium. Especially, D.P. 6 was more effective than D.P. 4 galactosyl mannooligosaccharide on the growth of Bifidobacterium spp.

• Journal of Korean Society of Steel Construction
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• v.22 no.1
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• pp.99-108
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• 2010

This paper presents the results of a study that aimed to develop a module for auto connection modeling that can be applied to the structural details design and modeling phase. It was established that the steel connection library database from the structural analysis resulted from the consideration of the input parameters of the 3D modeling program and the guidelines for Korean standard steel connections. The module for the auto connection modeling in steel structures was developed by linking it with the established library database through the use of the OpenAPI software to prove that the developed module carried out the modeling of the six story (steel structure) office building. The productivity and efficiency of the module introduction was verified by comparing the conventional process and the proposed process.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.209-212
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• 2000

본 논문은 음성인식에 필요한 대용량 음성 D/B 구축을 위한 auto-segmentation의 향상에 관한 논문이다. 50개의 우리말 음소(잡음, 묵음 포함)를 정하고 음성특징으로 MFCC(Mel Frequency Cepstral Coefficients), $\Delta$MFCC, $\Delta\Delta$MFCC, 39차를 추출한 다음 HMM 훈련과 CCS(Constrained Clustering Segmentation) 알고리즘(1)을 사용하여auto-segmentation을 수행하였다. 이 과정에서 대부분의 음소는 오류범위$(\pm25ms)$ 안에서 분절이 이루어지지만, 짧은 묵음, 모음+유성자음('ㅁ', 'ㄴ', 'ㄹ', 'o') 등에서 자주 오류범위를 넘어 분절이 발생하였다. 이러한 음운환경에 따른 경계의 오류를 구간별로 Wavelet 변환 신호의 MLR(Maximum Likelihood Ratio) 값을 이용, 기존 문제점을 보완하여 오류의 범위를 줄임으로서 auto-segmentation의 성능 향상을 얻을 수 있었다.

• Archives of design research
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• v.19 no.1 s.63
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• pp.69-78
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• 2006

Nowadays, the design and development of footwear are focused on not only to protect feet against some injuries also to satisfy its personality and high-quality based on customer' subjective sensibilities. Many image source based human sensibility is needed to establish concept of footwear by new idea in design process. For satisfying costumer's and designer's disires, this study is concerned to evaluate and analyze images using human sensibility and construct image source D/B according to the result. The image evaluation performed by internet is used 1,000 Images classified into four groups(structure or architecture, transportation device, natural articles and home appliance), and 300 subjects are participated. Finally, the web D/B is constructed by the result of image evaluation that is performed statistical analysis(basic statistic, factoranalysis and multi-scaled analysis).

• 한국정보통신설비학회:학술대회논문집
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• 2006.08a
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• pp.3-6
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• 2006

초고속 광대역서비스 제공을 위한 FTTH-PON 광선로의 특성을 시험하기 위해 선로구축 단계, 개통단계, 고장처리 단계로 나누어 측정할 수 있는 방법에 대해 고찰해 보았다. 시스템의 허용손실 기준에 따라 구축된 광선로는 대표적으로 광손실, 광반사손실을 측정하여 접속품질을 확인할 수 있는데 OTDR 및 광파워메터를 활용한 구간별 측정방법을 다루었다. 또한 광옥외선의 단말에 현장조립형광커넥터를 사용하는 경우 접속 후 불량여부를 판단하기 위한 실험 결과를 소개하였다.

• 한국도로학회:학술대회논문집
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• 2011.03a
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• pp.9-14
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• 2011

• The Journal of the Acoustical Society of Korea
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• v.29 no.8
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• pp.497-503
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• 2010

In this paper, evaluation of noise reduction performance of HVAC system for ships by means of HVAC mock-up system is presented. Test is done for six different types of HVAC elements including room unit, silencer, etc. It is found that when diameter of silencer is small and air flow is large, flow noise degrades insertion loss. However, as diameter of silencer becomes larger, the effect of flow noise becomes smaller, and insertion loss up to 25 dB is measured. It is observed that insertion loss of diffuser type room unit is usually between zero and 10 dB, whereas that of the nozzle type room unit can be down to - 15 dB. In addition, it is shown that changing duct arrangement can reduce cabin noise by up to 2 dB, and providing same air flow to each room unit is crucial for generating less noise.

• Proceedings of the Technology Innovation Conference
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• 1997.07a
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• pp.286-306
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• 1997

This paper analyses the B-ISDN evolution strategy based on economic perspective, in terms of its effect on national competitiveness and quality of life. In the beginning, it considers the economic characteristic related with the emergences of B-ISDN services. The economic goods resulting from their services is classified by producer and consumer goods. The time difference between R&D and investment is also included to identify the technology gap between countries. And then, this paper intensifies the economic approach by complementing the technical factors which include both the network evolutionary characteristic and cost-effective implementation. The feasible scenarios are thereby obtained, one for technologically advanced countries and two for technologically unadvanced countries. The result of this study shows that technologically advanced countries can not only intensify their national competitiveness but also enhance quality of life, but not in the case of technologically less advanced countries.

• International Journal of Highway Engineering
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• v.14 no.2
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• pp.11-17
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• 2012

This research describes how to predict a model of the tensile strain related to the fatigue cracking performance of several asphalt concrete structures through design of experiments(e.g., Response Surface Methodology) and harmony search(HS) algorithm. The axisymmetric analysis program of finite element method, which is the KICTPAVE, was used to determine the strain level at the interface layer between asphalt layer and lean concrete layer. Once the training database set of various strain levels was constructed under the several condition of layer stiffnesses and thicknesses in the asphalt concrete structures, the data set was trained through the HS algorithm in order to determine the regression coefficients defined based on a response surface methodology. Furthermore, the testing set, which was not used for the training procedure of HS algorithm, was also constructed in order to evaluate whether the regression coefficients of a prediction model can be appropriately applied for other cases in asphalt concrete structures.