• 제목/요약/키워드: WISE

검색결과 1,715건 처리시간 0.023초

상위 N개 항목의 추천 정확도 향상을 위한 효과적인 선호도 표현방법 (An Effective Preference Model to Improve Top-N Recommendation)

  • 이재웅;이종욱
    • 정보과학회 논문지
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    • 제44권6호
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    • pp.621-627
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    • 2017
  • 협업필터링은 사용자들이 평가한 항목들의 유사성을 기반으로 평가되지 않은 항목을 효과적으로 추천해주는 기법이다. 기존에는 사용자가 평가하지 않은 항목 중 상위 N개 항목의 추천 정확도를 높이기 위하여 사용자의 항목의 대한 상대적 선호도를 반영하는 쌍 기반 선호도(pair-wise preference)와 목록 기반 선호도(list-wise preference)가 제안되었다. 하지만 이러한 방법들은 사용자가 평가한 항목 간의 상대적인 선호도를 표현하는데 한계가 있으며, 각각의 항목들의 중요도를 반영할 수 없는 단점이 있다. 본 논문에서는 유사도 및 순위 값을 계산할 때 평점 선호도 표현 방법과 역 사용자 빈도수(inverse user frequency)를 이용하여 사용자의 잠재된 선호도를 표현하는 새로운 방법을 제안한다. 제안 방법을 메모리 기반 협업필터링에 적용하여 비교한 결과 기존 방법보다 최대 2배 이상 정확도가 향상되는 것을 확인할 수 있었다.

그리드 환경에서 서비스 기반 워크플로우 시스템 설계 및 구현 (Service Oriented Workflow System on Grid)

  • 최주호;권용원;류소현;정창성
    • 한국정보과학회:학술대회논문집
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    • 한국정보과학회 2005년도 한국컴퓨터종합학술대회 논문집 Vol.32 No.1 (A)
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    • pp.43-45
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    • 2005
  • 그리드 어플리케이션을 분산, 병렬 환경에서 효과적으로 만들기 위해, 그리드 포탈시스템인 Workflow based grid portal for problem Solving Environment(WISE)를 개발해왔다. WISE는 Globus Toolkit 2를 기반으로 그리드 워크플로우 기술을 사용하여 사용자가 좀 더 쉽게 그리드 어플리케이션을 프로그래밍 할 수 있는 환경을 제공한다. 그러나 현재 그리드 기술은 서비스 기반 구조(Open Grid Service Architecture)로 변화하고 있고 WISE도 기술적 흐름에 따라 그것을 충족시킬 수 있도록 변화해야 한다. 그래서 서비스 기반 구조에 대응할 수 있는 워크플로우 엔진을 새로 설계하여 WISE에 적용하고자 한다. 새로 설계한 시스템은 Service Oriented Workflow System on Grid(SOWS-G)이다. 이것은 계산량이 많은 문제에 대해 효과적으로 분산, 병렬 실행을 가능하게 하고, 다양한 워크플로우 패턴을 지원하며, 웹 서비스를 이용할 수 있도록 설계하였다. 이 논문에서는 SOWS-G를 서비스 기반 그리드 환경을 지원하는 Globus Toolkit 3를 이용하여 설계한 구조를 살펴보고 웹서비스를 이용할 수 있도록 추가된 기능들에 대해서 설명하고자한다.

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Reproduction of vibration patterns of elastic structures by block-wise modal expansion method (BMEM)

  • Jung, B.K.;Cho, J.R.;Jeong, W.B.
    • Smart Structures and Systems
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    • 제18권4호
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    • pp.819-837
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    • 2016
  • The quality of vibration pattern reproduction of elastic structures by the modal expansion method is influenced by the modal expansion method and the sensor placement as well as the accuracy of measured natural modes and the total number of vibration sensors. In this context, this paper presents an improved numerical method for reproducing the vibration patterns by introducing a block-wise modal expansion method (BMEM), together with the genetic algorithm (GA). For a given number of vibration sensors, the sensor positions are determined by an evolutionary optimization using GA and the modal assurance criterion (MAC). Meanwhile, for the proposed block-wise modal expansion, a whole frequency range of interest is divided into several overlapped frequency blocks and the vibration field reproduction is made block by block with different natural modes and different modal participation factors. A hollow cylindrical tank is taken to illustrate the proposed improved modal expansion method. Through the numerical experiments, the proposed method is compared with several conventional methods to justify that the proposed method provides the improved results.

Layer-wise numerical model for laminated glass plates with viscoelastic interlayer

  • Zemanova, Alena;Zeman, Jan;Janda, Tomas;Sejnoha, Michal
    • Structural Engineering and Mechanics
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    • 제65권4호
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    • pp.369-380
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    • 2018
  • In this paper, a multi-layered finite element model for laminated glass plates is introduced. A layer-wise theory is applied to the analysis of laminated glass due to the combination of stiff and soft layers; the independent layers are connected via Lagrange multipliers. The von $K{\acute{a}}rm{\acute{a}}n$ large deflection plate theory and the constant Poisson ratio for constitutive equations are assumed to capture the possible effects of geometric nonlinearity and the time/temperature-dependent response of the plastic foil. The linear viscoelastic behavior of a polymer foil is included by the generalized Maxwell model. The proposed layer-wise model was implemented into the MATLAB code and verified against detailed three-dimensional models in ADINA solver using different hexahedral finite elements. The effects of temperature, load duration, and creep/relaxation are demonstrated by examples.

Improved block-wise MET for estimating vibration fields from the sensor

  • Jung, Byung Kyoo;Jeong, Weui Bong;Cho, Jinrae
    • Structural Engineering and Mechanics
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    • 제64권3호
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    • pp.279-285
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    • 2017
  • Modal expansion technique (MET) is a method to estimate the vibration fields of flexible structures by using eigenmodes of the structure and the signals of sensors. It is the useful method to estimate the vibration fields but has the truncation error since it only uses the limit number of the eigenmodes in the frequency of interest. Even though block-wise MET performed frequency block by block with different valid eigenmodes was developed, it still has the truncation error due to the absence of other eigenmodes. Thus, this paper suggested an improved block-wise modal expansion technique. The technique recovers the truncation errors in one frequency block by utilizing other eigenmodes existed in the other frequency blocks. It was applied for estimating the vibration fields of a cylindrical shell. The estimated results were compared to the vibration fields of the forced vibration analysis by using two indices: the root mean square error and parallelism between two vectors. These indices showed that the estimated vibration fields of the improved block-wise MET more accurately than those of the established METs. Especially, this method was outstanding for frequencies near the natural frequency of the highest eigenmode of each block. In other words, the suggested technique can estimate vibration fields more accurately by recovering the truncation errors of the established METs.

영역기반 해쉬구조를 이용한 효율적 삼각형 자동 요소망 생성 알고리듬 개발 (An Efficient Triangular Mesh Generation Algorithm using Domain-wise Hash Structure)

  • 김태주;조진연
    • 한국항공우주학회지
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    • 제32권9호
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    • pp.41-48
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    • 2004
  • 본 논문에서는 빠른 요소망 자료 처리를 위해 영역기반 해쉬구조를 개발하고 이에 기반한 효율적 삼각형 자동 요소망 생성 알고리듬을 제안하였다. 제안된 알고리듬에서는 신속하게 최적의 절점을 생성하고 삼각형 생성시 예외처리를 줄일 수 있도록 Advancing layer method 와 Delaunay 삼각화 방법이 함께 이용되었다. 본 알고리듬의 성능을 검증하기 위하여 개발된 2차원 자동 요소망 생성 프로그램을 이용하여 볼록한 모델, 오목한 모델 및 복잡한 형태의 모델에 대한 요소망 생성 테스트를 수행하고, 그 성능을 상용 소프트웨어와 비교하였다.

Precision of predicted 3D numerical solutions of vortex-induced oscillation for bridge girders with span-wise varying geometry

  • Harada, Takehiko;Yoshimura, Takeshi;Tanaka, Takahisa;Mizuta, Yoji;Hashiguchi, Takafumi;Sudo, Makoto;Miyazaki, Masao
    • Wind and Structures
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    • 제7권1호
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    • pp.13-28
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    • 2004
  • A method of numerical analysis without conducting 3D wind tunnel model tests was examined in our previous study for predicting vortex-induced oscillation of bridge girders with span-wise varying geometry. The aerodynamic damping forces measured for plural wind tunnel 2D models were used in the analysis. A further study was conducted to examine the precision of solution obtained by this method. First, the responses of vortex-induced oscillation of two rocking models and a taut-strip bridge girder model with span-wise varying geometry were measured. Next, the responses of these models were numerically analyzed by means of this method, and then a comparison was made between the obtained $Vr-A-{\delta}_a$ contour diagram of each 3D model in the wind tunnel test and the diagram in the numerical analysis. Since close correlations were observed between each two $Vr-A-{\delta}_a$diagrams obtained in the model test and in the analysis in cases where the 3D model did not have strong three-dimensionality, our findings revealed that the predicted solution proved to be reasonably accurate.

Syllable-timing Interferes with Korean Learners' Speech of Stress-timed English

  • Lee, Ok-Hwa;Kim, Jong-Mi
    • 음성과학
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    • 제12권4호
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    • pp.95-112
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    • 2005
  • We investigate Korean learners' speech-timing of English before and after instruction in comparison with native speech, in an attempt to resolve disagreements in the literature as to whether speech-timing is measurable (Lehiste, 1977; Roach, 1982; Dauer, 1983 vs. Low et al., 2000; Yun 2002; Jian, 2004). We measured the pair-wise variability between the adjacent stressed and unstressed syllables within a foot as well as that among adjacent feet in approximately 555 English sentences, which were read by 29 native speakers and 41 Korean learners in the intermediate proficiency level. The results show that in comparison with native American English, Korean learner speech is before instruction significantly (p<.001) smaller for the pair-wise variability between the adjacent stressed and unstressed syllables within a foot; and significantly (p=.01) bigger for the variability among adjacent feet within the utterance. The learner speech after instruction showed significant (p=.01) improvement in the pair-wise variability of syllable sequence toward native speech values. The variability among adjacent feet was progressively smaller for learner speech before and after instruction and for native speech (p=.03). We thus conclude that the speech timing difference between Korean English and American English is measurable in terms of the duration. of stressed and unstressed syllables and that the latter is stress-timed and the former is syllable-timing interfered.

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Development of dynamic behavior of the novel composite T-joints: Numerical and experimental

  • Mokhtari, Madjid;Shahravi, Morteza;Zabihpoor, Mahmood
    • Advances in aircraft and spacecraft science
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    • 제5권3호
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    • pp.385-400
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    • 2018
  • In this paper dynamic behavior (modal analysis and dynamic transient response) of a novel sandwich T-joint is numerically and experimentally investigated. An epoxy adhesive is selected for bonding purpose and making the step wise graded behavior of adhesive region. The effect of the step graded behavior of the adhesive zone on dynamic behavior of a sandwich T-joint is numerically studied. Finite element analysis (FEA) of the T-joints with carbon fiber reinforced polymer (CFRP) face-sheets is performed by ABAQUS 6.12-1 FEM code software. Modal analysis and dynamic half-sine transient response of the sandwich T-joint are presented in this paper. Two verification processes employed to verify the dynamic modeling of the manufactured sandwich panels and T-joint modeling. It has been shown that the step wise graded adhesive zone cases have changed the second natural frequency by about 5%. Also, it has been shown that the different arranges in the step wise graded adhesive zone significantly affect the maximum stresses due to transient dynamic loading by 1112% decrease in maximum peel stress and 691.9% decrease in maximum shear stress on the adhesive region.

Demosaicing based Image Compression with Channel-wise Decoder

  • Indra Imanuel;Suk-Ho Lee
    • International Journal of Internet, Broadcasting and Communication
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    • 제15권4호
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    • pp.74-83
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    • 2023
  • In this paper, we propose an image compression scheme which uses a demosaicking network and a channel-wise decoder in the decoding network. For the demosaicing network, we use as the input a colored mosaiced pattern rather than the well-known Bayer pattern. The use of a colored mosaiced pattern results in the mosaiced image containing a greater amount of information pertaining to the original image. Therefore, it contributes to result in a better color reconstruction. The channel-wise decoder is composed of multiple decoders where each decoder is responsible for each channel in the color image, i.e., the R, G, and B channels. The encoder and decoder are both implemented by wavelet based auto-encoders for better performance. Experimental results verify that the separated channel-wise decoders and the colored mosaic pattern produce a better reconstructed color image than a single decoder. When combining the colored CFA with the multi-decoder, the PSNR metric exhibits an increase of over 2dB for three-times compression and approximately 0.6dB for twelve-times compression compared to the Bayer CFA with a single decoder. Therefore, the compression rate is also increased with the proposed method than with the method using a single decoder on the Bayer patterned mosaic image.