• 제목/요약/키워드: Resolution Schemes

검색결과 162건 처리시간 0.026초

서지식별기호를 이용한 URN 변환 시스템 설계에 대한 연구 - ISBN, ISSN, NBN을 중심으로 - (A Study on the Design of URN Resolution System Using Bibliographic Identifiers as URN - ISBN, ISSN, NBN as Its Central Issue -)

  • 김성준;홍현진
    • 한국도서관정보학회지
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    • 제33권4호
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    • pp.149-177
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    • 2002
  • URIs는 정보 접근의 신뢰성을 확보하기 위한 식별체계로서, 본 연구에서는 기존의 식별체계인 ISBN, ISSN, NBN을 URN으로 이용하여 URN 시스템을 설계하였다. 이를 위해서 URN의 기능적 요구사항, 부호화 요구사항, 구조적 측면을 바탕으로 서지식별기호들의 URN 사용 가능성을 분석하였다. 분석결과 ISBN, ISSN, NBN은 URN으로서 사용 가능성이 확인되었고. 이 결과를 바탕으로 RDS를 기반으로 한 서지식별 체계의 URN 변환 시스템을 각각 설계하였다.

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Characteristics of optimal solutions in kinematic resolutions of redundancy

  • Park, Jonghoon;Chung, W.K.;Youm, Y.
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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    • pp.908-913
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    • 1993
  • The inverse kinematic solutions for redundant manipulators using the optimality augmented resolution schemes have been used without investigating the characteristics of the optimal solutions. The questions with this kind of resolution methods are answered in this paper, that is (i) the characteristics of solutions, (ii) of algorithmic singularities, (iii) their dimensionality, and (iv) the invariance of the characteristics during resolutions. 3-DOF planar redundant robot is analyzed when the inverse kinematic method is applied with the manipulability as an example.

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선형 파면을 이용한 새로운 합성구경 기법 (A New Synthetic Aperture Technique Using Linear Wave Fronts)

  • 장진호;송태경
    • 대한의용생체공학회:의공학회지
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    • 제22권4호
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    • pp.321-330
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    • 2001
  • In this paper, we propose a new synthetic aperture focusing scheme for improving the lateral resolution which is one of the most important factors determining the quality of ultrasound imaging. The proposed scheme enables full round-trip dynamic focusing with approximately limited property. This properties are obtained through transmitting plane waves of which the traveling angle varies with the receive subaperture position, as opposed to stepping the spherical wave source across an array in other synthetic aperture focusing schemes, and employing dynamic focusing in receive. In this paper, the properties of the proposed scheme is analyzed in which a hypothetical infinite line source is used to transmit the plane waves and verified through computer simulation results. Also, we show that the proposed scheme is realizable with an array transducer with a finite aperture size. In summary, it is shown through comparison between the field contours of the proposed scheme and the conventional scheme that the proposed scheme can improve greatly the lateral resolution of ultrasound imaging.

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웨이브릿 변환을 사용한 초저속 전송 매체용 비디오 코딩 (Video coding based on wavelet transform for very low bitrate channel)

  • 오황석;이흥규
    • 한국통신학회논문지
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    • 제21권4호
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    • pp.822-833
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    • 1996
  • The video coding for very low bit rate has recently received considerable attention, but conventional block based transform coding schemes suffer from the blocking effect for the constraints of bit rates. In this paper, we present a video coding sysem suing multi-resolution motion estimation/compensation with variable size block(VMRME/C) and multi-resolution vector quantization(MRVQ) in wavelet transform domain for very low bit rate coding. It is shown that the presented scheme has better performance in the peak signal-to-nose ratio(RSNR) by 0.2-0.6 dB as well as subjective quality than that of conventional block based transform video coding techniques(especially, H. 263 which is DCT based video coding).

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Wheel Screen Type Lamina 3D Display System with Enhanced Resolution

  • Baek, Hogil;Kim, Hyunho;Park, Sungwoong;Choi, Hee-Jin;Min, Sung-Wook
    • Current Optics and Photonics
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    • 제5권1호
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    • pp.23-31
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    • 2021
  • We propose a wheel screen type Lamina 3D display, which realizes a 3D image that can satisfy the accommodation cue by projecting volumetric images encoded by varying polarization states to a multilayered screen. The proposed system is composed of two parts: an encoding part that converts depth information to states of polarization and a decoding part that projects depth images to the corresponded diffusing layer. Though the basic principle of Lamina displays has already been verified by previous studies, those schemes suffered from a bottleneck of inferior resolution of the 3D image due to the blurring on the surfaces of diffusing layers in the stacked volume. In this paper, we propose a new structure to implement the decoding part by adopting a form of the wheel screen. Experimental verification is also provided to support the proposed principle.

흉부 CT에 있어서 컴퓨터 보조 진단 (Computer-Aided Diagnosis in Chest CT)

  • 구진모
    • Tuberculosis and Respiratory Diseases
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    • 제57권6호
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    • pp.515-521
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    • 2004
  • With the increasing resolution of modern CT scanners, analysis of the larger numbers of images acquired in a lung screening exam or diagnostic study is necessary, which also needs high accuracy and reproducibility. Recent developments in the computerized analysis of medical images are expected to aid radiologists and other healthcare professional in various diagnostic tasks of medical image interpretation. This article is to provide a brief overview of some of computer-aided diagnosis schemes in chest CT.

상호작용 다중 모델 알고리듬을 이용한 표적 추적 (Target Tracking using Interacting Multilple Model Algorithm)

  • 구현철;서진헌
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1996년도 하계학술대회 논문집 B
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    • pp.943-945
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    • 1996
  • In this paper, we present an algorithm that allows tracking of a target using measurements obtained from a sensor with limited resolution. The Interacting Multiple Model (IMM) algorithm has been shown to be one of the most cost-effective estimation schemes for hybrid systems. The approach consists of IMM algorithm combined with a coupled version of the Joint Probabilistic Data Association Filter for the target that splits into two targets.

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NUMERICAL MODELING OF NON-CAPACITY MODEL FOR SEDIMENT TRANSPORT BY CENTRAL UPWIND SCHEME

  • S. JELTI;A. CHARHABIL;J. EL GHORDAF
    • Journal of applied mathematics & informatics
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    • 제41권1호
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    • pp.181-192
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    • 2023
  • This work deals with the numerical modeling of dam-break flow over erodible bed. The mathematical model consists of the shallow water equations, the transport diffusion and the bed morphology change equations. The system is solved by central upwind scheme. The obtained results of the resolution of dam-beak problem is presented in order to show the performance of the numerical scheme. Also a comparison of central upwind and Roe schemes is presented.

단일 전단 동축 분사기를 가지는 GH2/GO2 로켓 연소기의 고해상도 수치해석 (Numerical Study of High Resolution Schemes for GH2/GO2 Rocket Combustor using Single Shear Coaxial Injector)

  • 정승민;엄재령;최정열
    • 한국추진공학회지
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    • 제22권6호
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    • pp.72-83
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    • 2018
  • 본 연구에서는 단일 전단 동축 분사기를 이용한 수소 로켓 연소기의 전산유체 해석을 수행하였다. 2차원 축대칭 형상에서 난류연소 해석을 위해 hybrid RANS/LES 난류모델을 적용하였다. 적합한 해석기법을 찾기 위해 3가지 화학 반응기구, 3가지 고해상도 기법 및 3단계 격자해상도 조합을 비교하였다. 벽면 열유속을 실험결과와 비교하여 해석 성능을 살펴보았으며, 유동장 결과 분석으로 동축 분사기를 가지는 로켓 연소기의 난류연소특성을 살펴볼 수 있었다.

Preconditioned Jacobian-free Newton-Krylov fully implicit high order WENO schemes and flux limiter methods for two-phase flow models

  • Zhou, Xiafeng;Zhong, Changming;Li, Zhongchun;Li, Fu
    • Nuclear Engineering and Technology
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    • 제54권1호
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    • pp.49-60
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    • 2022
  • Motivated by the high-resolution properties of high-order Weighted Essentially Non-Oscillatory (WENO) and flux limiter (FL) for steep-gradient problems and the robust convergence of Jacobian-free Newton-Krylov (JFNK) methods for nonlinear systems, the preconditioned JFNK fully implicit high-order WENO and FL schemes are proposed to solve the transient two-phase two-fluid models. Specially, the second-order fully-implicit BDF2 is used for the temporal operator and then the third-order WENO schemes and various flux limiters can be adopted to discrete the spatial operator. For the sake of the generalization of the finite-difference-based preconditioning acceleration methods and the excellent convergence to solve the complicated and various operational conditions, the random vector instead of the initial condition is skillfully chosen as the solving variables to obtain better sparsity pattern or more positions of non-zero elements in this paper. Finally, the WENO_JFNK and FL_JFNK codes are developed and then the two-phase steep-gradient problem, phase appearance/disappearance problem, U-tube problem and linear advection problem are tested to analyze the convergence, computational cost and efficiency in detailed. Numerical results show that WENO_JFNK and FL_JFNK can significantly reduce numerical diffusion and obtain better solutions than traditional methods. WENO_JFNK gives more stable and accurate solutions than FL_JFNK for the test problems and the proposed finite-difference-based preconditioning acceleration methods based on the random vector can significantly improve the convergence speed and efficiency.