• Annual Conference on Human and Language Technology
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• 2007.10a
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• pp.194-201
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• 2007

인용 매칭(Citation Matching, CM)은 동일한 논문을 지칭하는 인용레코드(Citation Record)를 군집화하는 것으로 인용 관계를 가진 사회연계망 구축시 필요한 기술의 하나이다. 인용 매칭의 전단계로써, 인용 레코드를 저자, 논문 제목, 게재지명, 발행연도 등의 필드로 구분하는 인용 필드 분해가 고려될 수 있다. 본 논문은 인용 필드 분해(Citation Field Segmentation, CFS)와 인용 매칭의 상관관계를 분석하고자 한다. 즉, 인용 필드 분해가 인용 매칭에 필수적인 단계인지를 밝히고 개별 인용 필드가 인용 매칭에 미치는 영향을 분석한다. 실험을 통해 인용 필드 분해를 한 인용 매칭(CFS-based CM)이 인용 필드 분해를 적용하지 않은 인용 매칭(CFS-free CM)에 비해 1% 내외의 성능의 차이를 보이므로, 인용매칭의 성능에 크게 영향을 미친다고 보기 어려웠다. 이는 인용 레코드의 서로 다른 필드들 사이에서 어휘 중복 비율이 크게 낮기 때문에 따로 필드를 구별하지 않아도 필드가 구별되는 특성때문이었다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.5
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• pp.1187-1193
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• 2014

This paper presents an effective motion estimation to improve the performance of the motion compensated temporal filtering (MCTF) which is a core part of the wavelet-based scalable video coding. The proposed scheme makes the motion vector field uniform by the modified median operation and the search strategies using adjacent motion vectors, in order to enhance the pixel connectivity which is significantly relevant to the performance of the MCTF. Moreover, the motion estimation with variable block sizes that reflects the features of frames is introduced for further correlation improvement of the motion vector field. Experimental results illustrate that the proposed method reduces the decomposed energy on the temporal high frequency subband frame up to 30.33% in terms of variance compared to the case of the full search with fixed block sizes.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.8
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• pp.693-698
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• 2007

A numerical method for accurate simulations of rotor aerodynamics is proposed. The numerical diffusion in the typically coarse grids away from the rotor blades is improved by implying a fourth-order of interpolation of local characteristic variables of the flow in the reconstruction stage of MUSCL approach in the framework of a finite volume formulation. In addition, different slope limiters are applied to the different characteristic fields, such as compressive limiters to linear characteristic fields to reduce the numerical dissipation whereas, diffusive limiters to nonlinear characteristic fields to increase numerical stability. Various exemplary problems related to the rotor aerodynamics applications are tested and the numerical results show a significant improvement in wake capturing capability. However, rotor aeroacoustic calculations show no meaningful difference over traditional MUSCL approach.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.3
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• pp.247-255
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• 2010

Purpose: Developing a roofed Pechan prism type scope with long eye relief. Methods: To reduce the overall length and to lengthen the eye relief of scope, the objective part was designed by adopting the roofed Pechan prism and also the eyepiece part was designed by adopting the field lens with minus refractive power in front of reticle, respectively. Finally, by integrating above two parts, the roofed Pechan prism type scope with 90 mm eye relief was developed. Results: The characteristics of the developed and fabricated scope with 90 mm eye relief by integrating the objective part with the roofed Pechan prism and the eyepiece part with minus refractive power had the magnification of $+3.0{\times}$, the length from the 1st lens to the last lens of about 121 mm, the barrel diameter of 28 mm, and the effective objective-diameter of 17 mm. Also it was found that the line width of resolution was about 900 cycles/rad at the 50% MTF value criterion. Conclusions: We could design and manufacture the roofed Pechan prism type scope with 90 mm eye relief, the characteristics of which had the magnification of $3.0{\times}$, the MTF above 50% at 900 cycles/rad, and the length from the 1st lens to the last lens of about 121 mm.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.6
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• pp.69-78
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• 2017

Shannon of the 5G smartphone and Fourier of the signal processing meet in the sampling theorem (2 times the highest frequency 1). In this paper, the initial Shannon Theorem finds the Shannon capacity at the point-to-point, but the 5G shows on the Relay channel that the technology has evolved into Multi Point MIMO. Fourier transforms are signal processing with fixed parameters. We analyzed the performance by proposing a 2N-1 multivariate Fourier-Jacket transform in the multimedia age. In this study, the authors tackle this signal processing complexity issue by proposing a Jacket-based fast method for reducing the precoding/decoding complexity in terms of time computation. Jacket transforms have shown to find applications in signal processing and coding theory. Jacket transforms are defined to be $n{\times}n$ matrices $A=(a_{jk})$ over a field F with the property $AA^{\dot{+}}=nl_n$, where $A^{\dot{+}}$ is the transpose matrix of the element-wise inverse of A, that is, $A^{\dot{+}}=(a^{-1}_{kj})$, which generalise Hadamard transforms and centre weighted Hadamard transforms. In particular, exploiting the Jacket transform properties, the authors propose a new eigenvalue decomposition (EVD) method with application in precoding and decoding of distributive multi-input multi-output channels in relay-based DF cooperative wireless networks in which the transmission is based on using single-symbol decodable space-time block codes. The authors show that the proposed Jacket-based method of EVD has significant reduction in its computational time as compared to the conventional-based EVD method. Performance in terms of computational time reduction is evaluated quantitatively through mathematical analysis and numerical results.