• Title/Summary/Keyword: concentric structure

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3-D Wavelet Compression with Lifting Scheme for Rendering Concentric Mosaic Image (동심원 모자이크 영상 표현을 위한 Lifting을 이용한 3차원 웨이브렛 압축)

  • Jang Sun-Bong;Jee Inn-Ho
    • Journal of Broadcast Engineering
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    • v.11 no.2 s.31
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    • pp.164-173
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    • 2006
  • The data structure of the concentric mosaic can be regarded as a video sequence with a slowly panning camera. We take a concentric mosaic with match or alignment of video sequences. Also the concentric mosaic required for huge memory. Thus, compressing is essential in order to use the concentric mosaic. Therefore we need the algorithm that compressed data structure was maintained and the scene was decoded. In this paper, we used 3D lifting transform to compress concentric mosaic. Lifting transform has a merit of wavelet transform and reduces computation quantities and memory. Because each frame has high correlation, the complexity which a scene is detected form 3D transformed bitstream is increased. Thus, in order to have higher performance and decrease the complexity of detecting of a scene we executed 3D lifting and then transformed data set was sequently compressed with each frame unit. Each frame has a flexible bit rate. Also, we proposed the algorithm that compressed data structure was maintained and the scene was decoded by using property of lifting structure.

Seismic Performance of Low-rise Piloti RC Buildings with Concentric Core (중심코어를 가지는 저층 철근콘크리트 필로티 건물의 내진성능)

  • Yoon, Tae-Ho
    • Journal of the Korean Society of Industry Convergence
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    • v.25 no.4_2
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    • pp.611-619
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    • 2022
  • In this study, the seismic performance of low - rise piloti buildings with concentric core (shear wall) position is analysed and reviewed based on KDS 41. The prototype is selected among the constructed low - rise piloti buildings with concentric core designed based on KBC 2005 which was used for many low - rise piloti buildings construction. The seismic performance of the building shows plastic behavior in X-direction and elastic behavior in Y-direction. The inter-story drift is lager than that of concentric core case and is under the maximum allowed drift ratio. The displacement ratio of first story is much lager the that of upper stories, and the frame structure in the first story is evaluated as vulnerable to lateral force. Therefore, low - rise piloti buildings with concentric core need the diminishment of lateral displacement and reinforcement of lateral resistance capacity in seismic design and seismic retrofit.

Fluid-structure coupling of concentric double FGM shells with different lengths

  • Moshkelgosha, Ehsan;Askari, Ehsan;Jeong, Kyeong-Hoon;Shafiee, Ali Akbar
    • Structural Engineering and Mechanics
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    • v.61 no.2
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    • pp.231-244
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    • 2017
  • The aim of this study is to develop a semi-analytical method to investigate fluid-structure coupling of concentric double shells with different lengths and elastic behaviours. Co-axial shells constitute a cylindrical circular container and a baffle submerged inside the stored fluid. The container shell is made of functionally graded materials with mechanical properties changing through its thickness continuously. The baffle made of steel is fixed along its top edge and submerged inside fluid such that its lower edge freely moves. The developed approach is verified using a commercial finite element computer code. Although the model is presented for a specific case in the present work, it can be generalized to investigate coupling of shell-plate structures via fluid. It is shown that the coupling between concentric shells occurs only when they vibrate in a same circumferential mode number, n. It is also revealed that the normalized vibration amplitude of the inner shell is about the same as that of the outer shell, for narrower radial gaps. Moreover, the natural frequencies of the fluid-coupled system gradually decrease and converge to the certain values as the gradient index increases.

Turbulence Structures of Flow in Concentric Annuli with Rough Outer Wall (외벽에 거칠기가 있는 이중동심관 유동의 난류구조)

  • 김경천;안수환;이병규
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.9
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    • pp.2443-2453
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    • 1994
  • The structure of turbulence of fully developed flow through four concentric annuli with the rough outer wall was investigated experimentally for a Reynolds number range Re=15, 000-93, 000. Turbulence intensities were measured in three(u, v, w) directions, and turbulence shear stresses in annuli of radius=0.13, 0.26, 0.4 and 0.56, respectively. Due to the square roughness element attached periodically along the axial direction, the radial velocity fluctuations show similar distribution regardless of the different .alpha.cases. However, the axial and circumferential velocity fluctuation profiles demonstrate the longitudinal turbulence structures are strongly influenced by the .alpha. values. The turbulent eddy viscosity deduced form mean velocity distributions and the measured Reynolds shear stresses are also presented and discussed.

The Economic Consistency and the Creditworthiness of Borrower: the Methodical Features of Analysis Using the Concentric Matrix Models

  • VYBOROVA, Elena Nikolaevna
    • East Asian Journal of Business Economics (EAJBE)
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    • v.8 no.4
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    • pp.45-65
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    • 2020
  • Purpose - This paper is to analyze the system and the models of financial analysis in the assessment of economic consistency and the creditability of borrower. To test the process of complex express-analysis, it is utilized by the concentric matrix models by using the matrix of 5×5.. Research design, data, and methodology - The estimation of economic consistency, the creditworthiness, the complex express-analysis with application of concentric matrix models were carried out on the basis of data of the report for the 2017 of corporations POSCO and in the first half of the 2018 Daewoo Shipbuilding & Marine Engineering of South Korea. Results - This paper focused on the unbalance of the corporate financial structure (capital, receivable) and the assessment of sustainability development, taking into account the liquidity, solvency, financial sustainability and economic viability of the enterprise. Conclusions - this paper also consider the theoretical means of regulating receivables. The material is presented in the pedagogical context and appendix of the conclusion.

Performance Analysis of Cascade AOA Estimator with Concentric Ring Array Antenna (동심원 배열 안테나를 적용한 캐스케이드 도래각 추정 성능분석)

  • Kim, Tae-Yun;Hwang, Suk-Seung
    • The Journal of the Korea institute of electronic communication sciences
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    • v.15 no.5
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    • pp.849-856
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    • 2020
  • The Angle-of-Arrival(AOA) information for an array antenna receiver is one of the important factors for estimating the location of specific signals and detecting signals efficiently, in various situations. The AOA estimator in the satellite environment can rapidly calculate the AOA information in the wide area, utilizing a planar (grid, circular) array antenna mounted on the satellite. Since the satellite receiver has the limitation of the array antenna size, the concentric circular (ring) array (CCA or CRA) antenna structure with comparatively small size but with multiple antenna elements is more efficient than the uniform circular array (UCA) structure, for the satellite environment. In this paper, we introduce a cascade AOA estimation algorithm based on CRA, consisting of CAPON and Beamspace MUSIC. In addition, we provide computer simulation examples for verifying the estimation performance of the cascade AOA estimation algorithm based on CRA and compare it to the case of UCA.

Effect of Fluid Added Mass on Vibration Characteristics and Seismic Responses of Immersed Concentric Cylinders (유체속에 잠긴 동축원통 구조물의 진동특성 및 지진응답에 대한 유체부가질량 영향)

  • 구경회;이재한
    • Journal of the Earthquake Engineering Society of Korea
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    • v.5 no.5
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    • pp.25-33
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    • 2001
  • For the seismic design and analysis of LMR(liquid metal reactor) being developed in Korea, it is necessary to develop the simple seismic analysis model including the fluid-structure interaction effects. In this paper, the theoretical backgrounds for the fluid added mass of the immersed concentric cylinders are investigated and the seismic analysis code using the Runge-Kutta algorithm, which can consider the fluid added mass matrix in system matrix, are developed to perform the time history seismic analysis. Form the coupled modal analysis and the seismic analysis for the simple immersed concentric cylinders, it is verified that the fluid added mass significantly affect the vibration characteristics and the seismic responses. Therefore the fluid coupled effects should be carefully considered in seismic response analysis of the immersed concentric cylinders.

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Concentric Structure and Radial Joint System within Basic Lava Flow at the seashore of Aewol, Jeju Island, South Korea (제주도 애월읍 해안의 염기성 용암류에 발달한 동심원 구조와 방사상 절리)

  • Ahn, Kun Sang
    • Journal of the Korean earth science society
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    • v.42 no.2
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    • pp.185-194
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    • 2021
  • A lava dome and sheet lava flow can be observed at the seashore of Aewol, Jeju island. The cylindrical lobes are characterized by a concentric structure consisting of a massive core and radial joints. Columnar joints with different thickness between the upper and lower parts are developed in the sheet lava flow around the rock salt field in Goeomri. The upper part of the columnar joints is uneven in shape, and has a diameter of 120-150 cm. The lower part of the columnar joints is hexagonal and pentagonal in shape, and has a diameter of about 60 cm. The cylindrical lobes can be divided into two groups based on size and shape. One is a megalobe, with a semicircular outline and a maximum diameter of 30 m. The other is a circular lobe with a diameter of less than 10 m. The columns in the radial joints have hexagonal and pentagonal cross sections and gradually increasing diameter, outward from the core, to a size of 80-120 cm at the rim. The concentric structure observed in the cylindrical lavas is attributable to a combination of four factors. The first is a circular crack caused by the decrease of the temperature and density difference between the inside and outside of the cylindrical lava flow. The second is a concentric chisel mark of the radial joints, which formed at the same time as the radial joints. The third is a flow band, which is a trace left in a round passage when lava flows through. The fourth is a vesicular band formed in a cave by gas bubbles escaping from the lava flow.

Large-Eddy Simulation of Turbulent Flow in a Concentric Annulus with Rotation of the Inner Cylinder (안쪽 실린더가 회전하는 동심 환형관 내 난류 유동의 대형와 모사)

  • Chung, Seo-Yoon;Sung, Hyung-Jin
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.28 no.4
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    • pp.467-474
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    • 2004
  • A large-eddy simulation is performed for turbulent flow in a concentric annulus with the inner wall rotation at Re$\sub$Dh/=8900 for three rotation rates N=0.2145, 0.429 and 0.858. Main emphasis is placed on the inner wall rotation effect on near-wall turbulent structures. Near-wall turbulent structures close to the inner wall are scrutinized by computing the lower-order statistics. The anisotropy invariant map for the Reynolds stress tensor and the invariant function are illustrated to reveal the altered anisotropy in turbulent structure. Probability density functions of the splat/anti-splat process are explored to develop a sufficiently complete picture of the contributions of the flow events to turbulent production. The present numerical results show that the altered turbulent structures may be attributed to the centrifugal instability, which leads to the augmentation of sweep and ejection events.

Structure of turbulence of fully developed flow in concentric annuli with rough outer wall (거친외벽면을 가진 동심환형관내에서 완전히 발달된 유동의 난류구조)

  • Ahn, S.W.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.11 no.1
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    • pp.1-9
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    • 1999
  • For roughened annular pipes with diameter ratios of 0.26, 0.39, and 0.56 and with Reynolds numbers ranging 13,000 to 67,000, friction factor, autocorrelation coefficients, power spectral density functions, and integral length scales for each flow condition using X-type hot wire anemometry system are experimentally investigated. Distributions of these quantities show that the times which the streamwise autocorrelation coefficients become zero first increase with decreasing the radius ratios of concentric annuli and Reynolds numbers, however the power spectra density functions increase with increasing the radius ratios and Reynolds number.

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