• Title/Summary/Keyword: multi-phase

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3D Object Extraction Algorithm Based on Hierarchical Phase Using Fast Fourier Transform (고속 푸리에 변환을 이용한 계층적 위상기반 3차원 객체 추출 기법)

  • 한규필;이채수;박양우;엄태억
    • Proceedings of the IEEK Conference
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    • 2001.06c
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    • pp.145-148
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    • 2001
  • This paper presents a phase-based stereo matching algorithm in order to efficiently extract 3-dimensional objects from two 2D images. Conventional phase-based methods, especially using windowed Fourier phases, inherit good properties in the cage of hierarchical approaches, because they basically use a multi-resolution phase map. On the contrary, their computational cost is too heavy. Therefore, a fast hierarchical approach, using multi-resolution phase-based strategy and reducing redundancies of phase calculations based on FFT concept is proposed in this paper. In addition, a structural matching algorithm on the phase domain is presented to improve the matching quality. In experimental results. it is shown that the computation loads are considerably reduced about 8 times and stable outputs are obtained from various images.

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Phase-shedding in Boundary Conduction Mode Converter with Optimal Transition Load-level

  • Choi, Wooin;Baek, Jong-Bok;Cho, Bo-Hyung
    • Proceedings of the KIPE Conference
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    • 2011.11a
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    • pp.73-74
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    • 2011
  • Phase-shedding, one famous technology for multi-phase converters, is implemented in a bi-directional multi-phase converter for ESS. It reduces active operating modules at light load to compensate efficiency. Shedding point, the load level where the converter changes the number of active modules, is important factor that affects the effect of phase-shedding. Loss analysis is done for determining shedding point. Phase-shedding hysteresis is applied so that excessive phase transition is avoided. This paper proposes shedding point correction where the shedding point is adaptively corrected by calculating a new shedding point.

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An Investigation of Lattice Boltzmann Multi-phase Model and it Application (래티스볼츠만 다상류 모델의 검토 및 응용)

  • Kang, Ho-Keun;Ahn, Soo-Whan
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2006.06a
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    • pp.269-270
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    • 2006
  • A finite difference lattice Boltzmann model which allows us to simulate gas-liquid two-phase flows with large density difference, for instance, 800 times for air and water is considered. Two-particle model is used and the density difference is introduced by changing the acceleration according to the fluid density. Numerical measurement of surface tension agrees well with theoretical predictions. Simulations of two-phase phenomenon for phase-transition is carried out, showing applicability of the model for two-phase flows. The two-dimensional cavitating flow around a board set up in the fluid way is also simulated. As a result, it was confirmed that the FDLB method with two-particle model was effective in numerical simulation of cavitating flow and the bubble periodically grew up at the low pressure area behind the board, in which the fluid condition was influenced by the cavitation number.

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Phase Referencing Capability in KVN

  • Jeong, Tae-Hyeon;Son, Bong-Won
    • The Bulletin of The Korean Astronomical Society
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    • v.35 no.1
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    • pp.43.2-43.2
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    • 2010
  • Following the success of detecting fringes on KVN (Korean VLBI Network), a phase referencing observation is currently planned in order to achieve a better sensitivity in mm-VLBI. The high frequency observation ($\geq$ 22 GHz), wide bandwidths (~512 MHz) and high speed data recording (~1 Gbps, Mark5B) will result in resolution and sensitivity improvement on KVN. In particular, two powerful techniques of VLBI phase correction by fast-antenna switching and multi-frequency phase referencing are also introduced in KVN, hoping to resolve the problem of atmospheric delay errors which degrade the coherence significantly. In this study, we have compared the expected performance of phase referencing between fast antenna switching and multi-frequency phase referencing and discussed the essential condition and postulates of phase referencing for KVN.

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Multi-Scale Modelling of a Phase Mixture Model and the Finite Element Method for Nanocrystalline Materials (나노결정 재료의 상혼합모델과 유한요소법을 결합한 멀티스케일 모델링)

  • 윤승채;서민홍;김형섭
    • Transactions of Materials Processing
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    • v.13 no.2
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    • pp.174-179
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    • 2004
  • The effect of grain refinement on the plastic deformation behaviour of nanocrystalline metallic materials is investigated. A phase mixture model in which a single phase material is considered as an effectively two-phase one is discussed. A distinctive feature of the model is that grain boundaries are treated as a separate phase deforming by a diffusion mechanism. For the grain interior phase two concurrent mechanisms are considered: dislocation glide and mass transfer by diffusion. The proposed constitutive model was implemented into a finite element code (DEFORM) using a semicoupled approach. The finite element method was applied to simulating room temperature tensile deformation of Cu down to the nanoscale grain size in order to investigate the pre- and post-necking behaviour.

Design and Fabrication of a Phase Shifter RFIC using a Tunable Multi-layer Dielectric

  • Lee, Young Chul
    • Journal of Korea Society of Industrial Information Systems
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    • v.19 no.2
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    • pp.45-49
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    • 2014
  • In this work, a phase shifter radio-frequency integrated chip (RFIC) using a simple all-pass network is presented. As a tuning element of the phase shifter RFIC, tunable capacitors with a multi-layer dielectric of a para-/ferro-/para-electrics using a high tunable BST ferroelectric and a low-loss BZN paraelectric thin film were utilized. In order to evaluate and analyze the fabricated phase shifter RFIC, the same elements such as an inductor and capacitor integrated into it are also fabricated and tested. The designed phase shifter RFIC was fabricated on a quartz substrate in the size of $1.16{\times}1.21mm^2$. As the test results, the maximum phase difference of $350^{\circ}$ is obtained at 15 V and its tuning frequency bandwidth is 90 MHz from 2.72 to 2.81GHz.

A study on the activation characteristics of multi-phase Zr-based hydrogen storage alloy for Ni-MH rechargeable battery (Ni-MH 2차전지용 다상의 Zr계 수소저장합금 전극의 활성화 특성에 관한 연구)

  • Lee, Ho;Jang, Kuk-Jin;Lee, Jai-Young
    • Journal of Hydrogen and New Energy
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    • v.8 no.4
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    • pp.161-171
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    • 1997
  • $AB_2$ type Zr-based Laves phase alloys have been studied for potential application as negative electrode in Ni/MH batteries. However, They have a serious disadvantage of poor activation behavior in KOH solution. In this work, a new method of alloy design method was tried for improving Zr-based alloy activation. this method has focused on phase controlling to make multi-phase microstructure. In the case of multi-phase Zr-V-Mn-Ni shows good performance in activation, but activation mechanism has not been known. So, we were in search of elucidating this mechanism, Using morphological and electrochemical analysis, we could find that surface morphology and electocatalytic activity of the alloy change during immersion in KOH solution. V-rich second phases are selectively corroded and dissolved and then become Ni-rich phases. Resulting from these surface reaction in KOH solution, self-hydrogen charging occurs through Ni-rich phase. However, the alloy has poor cyclic durability because of such a corrosion mechanism. Therefore, finally we developed durable alloys by substitution of other alloying element.

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Implementation of Current Mode Control using Current Balance Controller of Multi-Phase Interleaved Boost Converter (다상 교호 승압컨버터의 전류평형제어기를 이용한 전류모드제어기 구현)

  • Park, Jong-Gyu;Choi, Hyun-Chil;Shin, Hwi-Beom
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.22 no.12
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    • pp.157-163
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    • 2008
  • In the multi-phase interleaved converter with peak current mode control, current imbalance is measured when inductors of converter module are not exactly identical. In this paper current-sharing controller is proposed to balance phase current of converter modules. It also is designed to have good transient response. Proposed method implemented the 2-phase and 4-phase interleaved boost converter with imbalanced inductance. Experimental results verify the performance of Current share during the transient state of converter.

A CBR-BASED COST PREDICTION MODEL FOR THE DESIGN PHASE OF PUBLIC MULTI-FAMILY HOUSING CONSTRUCTION PROJECTS

  • TaeHoon Hong;ChangTaek Hyun;HyunSeok Moon
    • International conference on construction engineering and project management
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    • 2009.05a
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    • pp.203-211
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    • 2009
  • Korean public owners who order public multi-family housing construction projects have yet to gain access to a model for predicting construction cost. For this reason, their construction cost prediction is mainly dependent upon historic data and experience. In this paper, a cost-prediction model based on Case-Based Reasoning (CBR) in the design phase of public multi-family housing construction projects was developed. The developed model can determine the total construction cost by estimating the different Building, Civil, Mechanical, Electronic and Telecommunication, and Landscaping work costs. Model validation showed an accuracy of 97.56%, confirming the model's excellent viability. The developed model can thus be used to predict the construction cost to be shouldered by public owners before the design is completed. Moreover, any change orders during the design phase can be immediately applied to the model, and various construction costs by design alternative can be verified using this model. Therefore, it is expected that public owners can exercise effective design management by using the developed cost prediction model. The use of such an effective cost prediction model can enable the owners to accurately determine in advance the construction cost and prevent increase or decrease in cost arising from the design changes in the design phase, such as change order. The model can also prevent the untoward increase in the duration of the design phase as it can effectively control unnecessary change orders.

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