• Title/Summary/Keyword: diagonal

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ON QB-IDEALS OF EXCHANGE RINGS

  • Chen, Huanyin
    • Bulletin of the Korean Mathematical Society
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    • v.46 no.5
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    • pp.873-884
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    • 2009
  • We characterize QB-ideals of exchange rings by means of quasi-invertible elements and annihilators. Further, we prove that every $2\times2$ matrix over such ideals of a regular ring admits a diagonal reduction by quasi-inverse matrices. Prime exchange QB-rings are studied as well.

The Enhanced Off-Diagonal Magneto-Impedance Effect in Cu/Ni80Fe20 Core-Shell Composite Wires Fabricated by Electrodeposition under Torsional Strain (비틀림 스트레인 하에서 전기도금으로 만든 Cu 코어/Ni80Fe20 쉘 복합 와이어에서 비대각 자기임피던스(Off-diagonal Magneto-Impedance) 효과의 증대)

  • Kim, Dong Young;Yoon, Seok Soo;Lee, Sang Hun
    • Journal of the Korean Magnetics Society
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    • v.27 no.4
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    • pp.135-139
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    • 2017
  • The magneto-impedance effect (MI effect) has been investigated in metal core/soft magnetic shell composite wires fabricated by electrodeposition of $Ni_{80}Fe_{20}$ on Cu wire (diameter $190{\mu}m$). The diagonal impedances $Z_{zz}$ and $Z_{{\theta}{\theta}}$ in cylindrical coordinate showed strong MI effect for the magnetic field applied along z-axis, while the off-diagonal impedance $Z_{{\theta}z}$ showed very weak MI effect. We have tried to develop the Cu $core/Ni_{80}Fe_{20}$ shell composite wire having strong MI effect in off-diagonal impedance by electrodeposion under torsional strain. The core/shell composite wire electrodeposited under torsional angles above $270^{\circ}$ showed significantly enhanced MI effect in the off-diagonal impedance. The maximum MI effect was observed in the composite wire electrodeposited under torsional angle of $360^{\circ}$. The developed method to enhance off-diagonal MI effect is expected to increase the applicability of the core/shell composite wire to magnetic sensor material.

Internal Flow Analyses of Diagonal Type Blowers Using a Quasi-3-Dimensional Method Considering Spanwise Mixing and Tip Clearance Effect Due to Secondary Flows (이차흐름에 의한 스팬방향의 믹싱효과와 선단틈새흐름을 고려한 준 삼차원 사류송풍기 내부흐름 해석)

  • Kim, Chan-Kyu;Jun, Yong-Du;Kim, Tae-Whan
    • 유체기계공업학회:학술대회논문집
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    • 2002.12a
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    • pp.137-146
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    • 2002
  • This paper presents a quasi-3-dimensional calculation method considering secondary flows in the impellers of diagonal flow blowers. A Quantitative estimation of the secondary flow effects is made by using secondary flow theories. In order to verify the validity of the adopted models, that is, span-wise mixing model and the tip clearance model, numerical simulations are performed for two different types of impellers of diagonal flow blowers which are designed differently. Numerical experiments are conducted for each of a constant tangential velocity type impeller, and a free vortex type impeller, both at two different flow coefficients. According to the simulation results, it was found that the present model considering span-wise mixing and tip clearance effect shows better agreements with the experimental data than those without these models in terms of the flow velocity and the angle distribution.

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MIMO Channel Diagonalization: Linear Detection ZF, MMSE (MIMO 채널 대각화: 선형 검출 ZF, MMSE)

  • Yang, Jae Seung;Shin, Tae Chol;Lee, Moon Ho
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.16 no.1
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    • pp.15-20
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    • 2016
  • Compared to the MIMO system using the spatial multiplexing methods and the MIMO system using the diversity scheme achieved a high rate, but the lower the diversity gain to improve the data transmission reliability should separate the spatial stream at the MIMO receiver. In this paper, we compared Channel capacity detection methods with the Lattice code, the 3-user interference channel and linear channel interference detection methods ZF (Zero Forcing) and MMSE (Minimum Mean Square Error) detection methods. The channel is a Diagonal channel. In other words, Diagonal channel is confirmed by the inverse matrix satisfies the properties of Jacket are element-wise inverse to $[H]_N[H]_N^{-1}=[I]_N$.

Effects of Covariance Modeling on Estimation Accuracy in an IMU-based Attitude Estimation Kalman Filter (IMU 기반 자세 추정 칼만필터에서 공분산 모델링이 추정 정확도에 미치는 영향)

  • Choi, Ji Seok;Lee, Jung Keun
    • Journal of Sensor Science and Technology
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    • v.29 no.6
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    • pp.440-446
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    • 2020
  • A well-known difficulty in attitude estimation based on inertial measurement unit (IMU) signals is the occurrence of external acceleration under dynamic motion conditions, as the acceleration significantly degrades the estimation accuracy. Lee et al. (2012) designed a Kalman filter (KF) that could effectively deal with the acceleration issue. Ahmed and Tahir (2017) modified this method by adjusting the acceleration-related covariance matrix because they considered covariance modeling as a pivotal factor in the estimation accuracy. This study investigates the effects of covariance modeling on estimation accuracy in an IMU-based attitude estimation KF. The method proposed by Ahmed and Tahir can be divided into two: one uses the covariance including only diagonal components and the other uses the covariance including both diagonal and off-diagonal components. This paper compares these three methods with respect to the motion condition and the window size, which is required for the methods by Ahmed and Tahir. Experimental results showed that the method proposed by Lee et al. performed the best among the three methods under relatively slow motion conditions, whereas the modified method using the diagonal covariance with a high window size performed the best under relatively fast motion conditions.

Nonlinear Analysis of Cyclic Lateral Forced RC Shear Wall (반복 횡하중을 받는 철근콘크리트 전단벽의 비선형 해석)

  • Kim, Geon-Woo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.14 no.5
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    • pp.161-168
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    • 2010
  • Practicing engineers and researchers need computational tools that estimate accurately the cyclic response of RC walls, and in particular, force and deformation capacities and their materials strains. So this paper describes a nonlinear truss modeling approach for reinforced concrete walls, or in general, for plane stress reinforced concrete elements subjected to cyclic reversals. Nonlinear vertical, horizontal, and diagonal truss elements are used to represent concrete and steel reinforcement. The wall having aspect ratio of 1.2 was chosen to be compared with the experimental results. Here, four types of main diagonal member models and three types of diagonal members models were applied to find out more accurate results of analysis.

Evaluation of Reinforcement Detail Effect on Coupling Beams (연결보의 배근 상세 효과 평가)

  • Lee, Hyun-Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.25 no.2
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    • pp.49-57
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    • 2021
  • A study was conducted to secure structural performance as well as improve workability by improving the reinforcement details of special shear wall and coupling beams. Based on the specimen in which the existing diagonal bundle reinforcement and shear reinforcement were placed, the specimens replaced with thick diagonal reinforcing bars and the specimens replaced with horizontal reinforcing bars were selected as variables. As a result of the experiment, the specimen, which replaced the existing diagonal reinforcement with a thick-diameter reinforcement, showed a similar behavior to that of the basic specimen, and it was evaluated that it can be applied as an alternative to the details.