• Title/Summary/Keyword: 3-Dimensional Shape Estimation

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A Study on the Vibration Analysis of a Deckhouse of Fishing Vessel (어선의 갑판실의 진동 해석법에 관한 연구)

  • 배동명
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.27 no.3
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    • pp.193-210
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    • 1991
  • For the deckhouse or superstructure, attention is directed to the reduction of vibration from a human susceptibility point of view. The two basic requirements for obtaining a low vibration level in the accommodation are to ensure that excitation forces from propeller and/or main engine are small and to avoid resonance excitation of the hull and superstructure. In recent years increased attention has been directed towards the problems of vibration and noise in deckhouse, which have caused major problems with regard to the environmental quality in the living quarters for crews. Accordingly, in this paper, the characteristic of the vibration of deckhouse of fishing boat, of which the length/height ratio is also relatively high, are studied systematically with regard to the shape and modelling of deckhouse based on finite element method of 1-dimensional, 2-dimensional and 3-dimensional model. This study is divided into 4-part. 1st part is the global deckhouse vibration, 2nd part is the local deckhouse vibration, 3rd part consists of the estimation for stiffness of foundational support and 4th part is the application to TUNA LONG LINER of 416 ton class. For the global vibration analysis, the severity of the vibration depends on the longitudinal shear and bending stiffness of the deckhouse, on the vertical deckhouse support(fore, aft and sides). However, even if the design is technically sound, vibration problems may arise due to vertical or longitudinal hull girder or afterbody resonances. Author applied the method of this study to the analysis of, deep-sea fishing vessel of G.T. 416 ton class with relatively low height and long deckhouse, and investigated the vibrational characteristic of the fishing vessel with earlier structural feature. According to this investigation, the vibration, response of above vessel was confirmed of which main hull and deckhouse behave as one body. It is at the bottom of vibrational trouble which a accommodation part of the fishing vessel is raised, that is the local vibration for side wall, fore-aft wall and deck plate of deckhouse rather than thief fect of fore-aft vibration of deckhouse for above fishing vessel. and the resonance of main hull, deckhouse and driving system such as the main engine, propeller in exciting source is mainly brought up as the trouble.

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Effect of Design Factors on the Performance of Stratified Thermal Storage Tank (성층축열조의 성능에 대한 설계인자의 영향)

  • Chung Jae Dong;Park Joohyuk;Cho Sung-Hwan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.16 no.11
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    • pp.1077-1083
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    • 2004
  • This study is to systematically analyze the effect of various kinds of design factors on the performance of stratified thermal storage tank. Taguchi method, known as a very reasonable tool in the parametric study, is employed in the present work. Three dimensional unsteady numerical experiment is conducted for 4 design parameters of stratified thermal storage tank: inlet Reynolds number, Froude number, diffuser size d with 3 levels (Re=400, 800, 1200, Fr=0.5, 1.0, 2.0 and d=150 mm, 200mm, 300 mm) and diffuser shape with 2 levels. Orthogonal array $L_{18}(2{\times}3^7)$ is adopted for the analysis of variance. The result gives quantitative estimation of the various design parameters affecting the performance and helps to select the main factors for the optimum design of stratified thermal storage tank. Reynolds number is found to be the most dominant parameter and the diffuser shape plays significant role on the performance of stratified thermal storage tank. Based on this finding, the prior questions on the contribution of the diffuser shape proposed by the authors become clear. The optimum condition for the performance is a set of d=300mm, Re=800, and radial regulated plate diffuser. Conformation test shows the repeatability in the analysis and $1.3\%$ difference between the estimated thermocline thickness and that of numerical result.

Moving Object Extraction and Relative Depth Estimation of Backgrould regions in Video Sequences (동영상에서 물체의 추출과 배경영역의 상대적인 깊이 추정)

  • Park Young-Min;Chang Chu-Seok
    • The KIPS Transactions:PartB
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    • v.12B no.3 s.99
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    • pp.247-256
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    • 2005
  • One of the classic research problems in computer vision is that of stereo, i.e., the reconstruction of three dimensional shape from two or more images. This paper deals with the problem of extracting depth information of non-rigid dynamic 3D scenes from general 2D video sequences taken by monocular camera, such as movies, documentaries, and dramas. Depth of the blocks are extracted from the resultant block motions throughout following two steps: (i) calculation of global parameters concerned with camera translations and focal length using the locations of blocks and their motions, (ii) calculation of each block depth relative to average image depth using the global parameters and the location of the block and its motion, Both singular and non-singular cases are experimented with various video sequences. The resultant relative depths and ego-motion object shapes are virtually identical to human vision.

The Estimation of Temperature distribution around Gas Storage Cavern (저온가스 저장공동 주위암반의 온도분포 예측에 관한 연구)

  • Lee, Yang;Lee, Seung-Do;Moon, Hyun-Koo
    • Tunnel and Underground Space
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    • v.14 no.1
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    • pp.16-25
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    • 2004
  • As underground caverns have many advantages such as safety and operation, they can also be used for gas storage purpose. When liquefied gas is stored underground, the cryogenic temperature of the gas affects the stability of the storage cavern. In order to store the liquefied gas successfully, it is essential to estimate the exact temperature distribution of the rock mass around the caverns. The main purpose of this study is the development of theoretical solution to be able to estimate the temperature distribution around storage caverns and the assessment of the solution. In this study, a theoretical solution and a conceptual model for estimating two and three dimensional temperature distribution around the storage caverns are suggested. Based on the multi-dimensional transient heat transfer theory, the theoretical solution is successfully derived by assuming the caverns shape as simplified geometry. In order to assess the theoretical solution, by performing numerical experiments with this multi-dimensional model, the temperature distribution of the theoretical solution is compared with that of numerical analysis. Furthermore, the effects of the caverns size are investigated.

Estimation of Elastic Fracture Mechanics Parameters for Slanted Axial Through-Wall Cracks for Leak-Before-Break and Crack Growth Analysis (파단전누설 해석 및 균열거동 평가를 위한 축방향 경사관통균열의 탄성 응력확대계수 및 균열열림변위)

  • Huh, Nam-Su;Shim, Do-Jun;Choi, Suhn;Park, Keun-Bae
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.725-726
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    • 2008
  • This paper proposes elastic stress intensity factors and crack opening displacements (CODs) for a slanted axial through-wall cracked cylinder under an internal pressure based on detailed 3-dimensional (3-D) elastic finite element (FE) analyses. Based on the elastic FE results, the stress intensity factors along the crack front and CODs through the thickness at the center of the crack were provided. These values were also tabulated for three selected points, i.e., the inner and outer surfaces and at the mid-thickness. The present results can be used to evaluate the crack growth rate and leak rate of a slanted axial through-wall crack due to stress corrosion cracking and fatigue. Moreover, the present results can be used to perform a detailed Leak-Before-Break analysis considering more realistic crack shape development.

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Thermal Elasto-Plastic Deformation Analysis of Metal Matrix Composites Considering Residual Stress and Interface Bonding Strength (잔류응력과 계면접합강도를 고려한 금속복합재료의 열탄소성 변형 해석)

  • Kang, Chung-Gil;Seo, Young-Ho
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.1 s.94
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    • pp.227-237
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    • 1999
  • As the interface bonding phenomenon between the matrix and the reinforcements has a large effect on the mechanical properties of MMCs, a sugestion of the strength analysis technique considering the residual stress and the interface bonding phenomenon is very important for the design of pans and the estimation of fatigue behavior. In this paper the three dimensional finite element anaysis is performed during the elasto-plastic deformation of the particulate reinforced metal matrix composites. It was analyzed with the volume fractions in view of microscale. Bonding strength. interface separation and matrix void growth between the matrix and the reinforcements will be predicted on deformation under tensile loading. An interface seperation is estimated by the fracture criterion which is a critical value of generalized plastic work per unit volume. The shape of the reinforcement is assumed to be a perfect sphere. And the type of the reinforcement distribution is assumed as FCC array. The thermal residual stress in MMCs is induced by the heat treatment. It is included at the simulation as an initial residual stress. The element birth and death method of the ANSYS program is used for the estimation of the interface bonding strength, void generation and propagation. It is assumed that the fracture in the matrix region begin to occur under the external loading when the plastic work per unit volume is equal to the critical value. The fracture strain will be defined. The experimental data of the extruded $SiC_p$>/606l Al composites are compared with the theoretical results.

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Motion Analysis Using Competitive Learning Neural Network and Fuzzy Reasoning (경쟁학습 신경망과 퍼지추론법을 이용한 움직임 분석)

  • 이주한;오경환
    • Journal of the Korean Institute of Intelligent Systems
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    • v.5 no.3
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    • pp.117-127
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    • 1995
  • In this paper, we suggest a motion analysis method using ART-I1 competitive learning neural network and fuzzy reasoning by matching the same objects through the consecutive image sequence. we use the size and mean intensity of the region obtained from image segmentation for the region matching by the region and use a ART-I1 competitive learning neural network wh~ch has a learning ability to reflect the topology of the input patterns in order to select characteristic points to describe the shape of a region. Motion vectors for each regions are obtained by matching selected characteristic points. However, the two dimensional image, the projection of the the three dimensional real world, produces fuzziness in motion analysis due to its incompleteness by nature and the error from image segmentation used for extracting information about objects. Therefore, the belief degrees for each regions are calculated using fuzzy reasoning to l-nanipulate uncertainty in motion estimation.

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Study on the 2G High Temperature Superconducting Coil for Large Scale Superconducting Magnetic Energy Storage Systems (대용량 에너지 저장장치용 2세대 고온 초전도 코일의 특성해석)

  • Lee, Ji-Young;Lee, Seyeon;Kim, Yungil;Park, Sang Ho;Choi, Kyeongdal;Lee, Ji-Kwang;Kim, Woo-Seok
    • KEPCO Journal on Electric Power and Energy
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    • v.1 no.1
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    • pp.157-162
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    • 2015
  • Large scale superconducting magnetic energy storage (SMES) system requires very high magnetic energy density in its superconducting coils to enhance the energy capacity and efficiency of the system. The recent high temperature superconducting (HTS) conductors, so called 2G conductors, show very good performance under very high magnetic field so that they seem to be perfect materials for the large scale SMES coils. A general shape of the coil system with the 2G HTS conductor has been a tor oid, because the magnetic field applied perpendicularly to the surface of the 2G HTS conductor could be minimized in this shape of coil. However, a toroid coil requires a 3-dimensional computation to acquire the characteristics of its critical current density - magnetic field relations which needs very complicated numerical calculation, very high computer specification, and long calculation time. In this paper, we suggested an analytic and statistical calculation method to acquire the maximum magnetic flux density applied perpendicularly to the surface of the 2G HTS conductor and the stored energy in the toroid coil system. Although the result with this method includes some errors but we could reduce these errors within 5 percent to get a reasonable estimation of the important parameters for design process of the HTS toroid coil system. As a result, the calculation time by the suggested method could be reduced to 0.1 percent of that by the 3-dimensional numerical calculation.

Seismic Design of Vertical Shaft using Response Displacement Method (응답변위법을 적용한 수직구의 내진설계)

  • Kim, Yong-Min;Jeong, Sang-Seom;Lee, Yong-Hee;Jang, Jung-Bum
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.6C
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    • pp.241-253
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    • 2010
  • For seismic design of a vertical shaft, three-dimensional Finite Element (FE) analyses were performed to evaluate the accurate response of a vertical shaft and to apply a Response Displacement Method (RDM). Special attention is given to the evaluation of seismic base and response displacement of surrounding soil, estimation of load and loading method. Based on the result, it was found that shear wave velocity of seismic base greater than 1500m/s was appropriate for the seismic design. It was also found that double cosine method which evaluates a response displacement of surrounding soil was most appropriate to consider the characteristic of multi-layered soil. Finally, shape effect of the structure was considered to clarify the dynamic behavior of vertical shaft and it would be more economical vertical shaft design when a vertical shaft was analyzed by using RDM.

Development and Verification of 4-Electrode Resistivity Probe (4전극 전기비저항 탐사장비의 개발 및 검증)

  • Kim, Joon-Han;Yoon, Hyung-Koo;Jung, Soon-Hyuck;Lee, Jong-Sub
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.3C
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    • pp.127-136
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    • 2009
  • The objective of this study is the development and verification of the 4-electrode resistivity probe (4ERP) for the estimation of electrical properties of the saturated soils. The 4ERPs with wedge and plane types are manufactured to obtain the electrical resistivity without polarization at the electrodes by using Wenner array. The wedge type is for the penetration into the soil samples and the plane type is for the installation into the cells used for the laboratory tests. The consolidation tests are carried out by using 6 types of glass beads and 3 types of sands in size. The test results show that the electrical resistivity increases with a decrease in the porosity, and the constant m used in Archie's law is dependent on the particle shape rather particle size. The one dimensional liquefaction tests show that the porosity obtained by the 4ERP is similar to that determined by the volume fraction. The penetration of the 4ERP into the large scale calibration chamber produces the resistivity profiles. This study demonstrates that the 4ERP may effectively estimate the porosity of the saturated soils.