• Title/Summary/Keyword: Cross current

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Design of a Low Power Capacitor Cross-Coupled Common-Gate Low Noise Amplifier (캐패시터 크로스 커플링 방법을 이용한 5.2 GHz 대역에서의 저전력 저잡음 증폭기 설계)

  • Shim, Jae-Min;Jeong, Ji-Chai
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.23 no.3
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    • pp.361-366
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    • 2012
  • This paper proposes a low power capacitor cross-coupled 5.2 GHz band low noise amplifier(LNA) using the current-reused topology with the TSMC 0.18 ${\mu}m$ CMOS process. The proposed 5.2 GHz band LNA uses a capacitor cross-coupled $g_m$-boosting method for reducing current flow of circuit and a current-reused topology to decrease total power dissipation. The parallel LC networks are used to reduce size of spiral inductors. The simulation results show high gain of 17.4 dB and noise figure(NF) of 2.7 dB for 5.2 GHz.

Generalized cross correlation with phase transform sound source localization combined with steered response power method (조정 응답 파워 방법과 결합된 generalized cross correlation with phase transform 음원 위치 추정)

  • Kim, Young-Joon;Oh, Min-Jae;Lee, In-Sung
    • The Journal of the Acoustical Society of Korea
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    • v.36 no.5
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    • pp.345-352
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    • 2017
  • We propose a methods which is reducing direction estimation error of sound source in the reverberant and noisy environments. The proposed algorithm divides speech signal into voice and unvoice using VAD. We estimate the direction of source when current frame is voiced. TDOA (Time-Difference of Arrival) between microphone array using the GCC-PHAT (Generalized Cross Correlation with Phase Transform) method will be estimated in that frame. Then, we compare the peak value of cross-correlation of two signals applied to estimated time-delay with other time-delay in time-table in order to improve the accuracy of source location. If the angle of current frame is far different from before and after frame in successive voiced frame, the angle of current frame is replaced with mean value of the estimated angle in before and after frames.

CFD Analysis of Trap Effect of Groove in Lubricating Systems: Part I - Variation in Cross-Sectional Shape of Groove (그루브의 Trap 효과에 대한 CFD 해석: 제 1부 − 그루브 단면 형상의 변화)

  • Hong, Sung-Ho
    • Tribology and Lubricants
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    • v.32 no.3
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    • pp.101-105
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    • 2016
  • Trap effect of groove is evaluated in a lubricating system using computational fluid dynamics (CFD) analysis. The simulation is based on the standard k-ε turbulence model and the discrete phase model (DPM) using a commercial CFD code FLUENT. The simulation results are also capable of showing the particle trajectories in flow field. Computational domain is meshed using the GAMBIT pre-processor. The various grooves are applied in order to improve lubrication characteristics such as reduction of friction loss, increase in load carrying capacity, and trapping of the wear particles. Trap effect of groove is investigated with variations in cross-sectional shape and Reynolds number in this research. Various cross-sectional shapes of groove (rectangular, triangle, U shaped, trapezoid, elliptical shapes) are considered to evaluate the trap effect in simplified two-dimensional sliding bearing. The particles are assumed to steel, and defined a single particle injection condition in various positions. The “reflect” boundary condition for discrete phase is applied to the wall boundary, and the “escape” boundary condition to “pressure inlet” and “pressure outlet” conditions. The streamlines are compared with particles trajectories in the groove. From the results of numerical analysis in the study, it is found that the cross-sectional shapes favorable to the creation of vortex and small eddy current are effective in terms of particle trapping effect. Moreover, it is found that the Reynolds number has a strong influence on the pattern of vortex or small eddy current in the groove, and that the pattern of the vortex or small eddy current affects the trap effect of the groove.

Flow Analysis of Profile Extrusion by a Modified Cross-sectional Numerical Method

  • Seo, Dongjin;Youn, Jae-Ryoun
    • Fibers and Polymers
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    • v.1 no.2
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    • pp.103-110
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    • 2000
  • Flow analysis of profile extrusion is essential for design and production of a profile extrusion die. Velocity, pressure, and temperature distribution in an extrusion die are predicted and compared with the experimental results. A two dimensional numerical method is proposed for three dimensional analysis of the flow field within the profile extrusion die by applying a modified cross-sectional numerical method. Since the cross-sectional shape of the die is varied gradually, it is assumed that the pressure is constant within a cross-sectional plane that is perpendicular to the flow direction. With this assumption, the velocity component in the cross-sectional direction is neglected. The exact cross-sectional shape at any position is calculated based on the geometry of standard cross-sections. The momentum and energy equations are solved with proper boundary conditions at a cross-section and then the same calculation is carried out for the next cross-section using the current calculated values. An L-shaped profile extrusion die is produced and employed for experimental investigation using a commercially available polypropylene. Numerical prediction for the varying cross-sectional shape provides better results than the previous studies and is in good agreement with the experimental results.

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Image Path Searching using Auto and Cross Correlations

  • Kim, Young-Bin;Ryu, Kwang-Ryol
    • Journal of information and communication convergence engineering
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    • v.9 no.6
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    • pp.747-752
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    • 2011
  • The position detection of overlapping area in the interframe for image stitching using auto and cross correlation function (ACCF) and compounding one image with the stitching algorithm is presented in this paper. ACCF is used by autocorrelation to the featured area to extract the filter mask in the reference (previous) image and the comparing (current) image is used by crosscorrelation. The stitching is detected by the position of high correlation, and aligns and stitches the image in shifting the current image based on the moving vector. The ACCF technique results in a few computations and simplicity because the filter mask is given by the featuring block, and the position is enabled to detect a bit movement. Input image captured from CMOS is used to be compared with the performance between the ACCF and the window correlation. The results of ACCF show that there is no seam and distortion at the joint parts in the stitched image, and the detection performance of the moving vector is improved to 12% in comparison with the window correlation method.

Application of matrix methods to scattering by conducting bodies (매트릭스 법에 의한 완전 도체의 산란 특성)

  • Kim, Chul-Hoo;Kim, Che-Young;Yu, Sang-Dae
    • Proceedings of the KIEE Conference
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    • 1988.07a
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    • pp.335-338
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    • 1988
  • A numerical method is presented for the scattering by the perfectly conducting cylinder with arbitrary cross sections. The relevant integral equation considered by the E-field formulation is solved by method of moments, and thereby the surface current induced as well as the radar cross section of the scatterer are numerically computed to specify the scattering nature of the scatterer. Two separate methods, one with point matching and the other Galerkin's method, are considered to make cross checks to the results obtained. Taking two half pulses suggested to expand the surface current shows savings in computation time and accurate solutions for the corners on the scatterer.

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Lagged Cross-Correlation of Probability Density Functions and Application to Blind Equalization

  • Kim, Namyong;Kwon, Ki-Hyeon;You, Young-Hwan
    • Journal of Communications and Networks
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    • v.14 no.5
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    • pp.540-545
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    • 2012
  • In this paper, the lagged cross-correlation of two probability density functions constructed by kernel density estimation is proposed, and by maximizing the proposed function, adaptive filtering algorithms for supervised and unsupervised training are also introduced. From the results of simulation for blind equalization applications in multipath channels with impulsive and slowly varying direct current (DC) bias noise, it is observed that Gaussian kernel of the proposed algorithm cuts out the large errors due to impulsive noise, and the output affected by the DC bias noise can be effectively controlled by the lag ${\tau}$ intrinsically embedded in the proposed function.

The Cross Section Analysis CSA based on the Short Circuit Conditions of the Low Voltage Bare Wires (저압용 나전선의 단락조건에 의한 단면 분석)

  • Shong, Kil-Mok;Kim, Dong-Ook;Kim, Dong-Woo;Kim, Young-Seok;Choi, Chung-Seog
    • Proceedings of the KIEE Conference
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    • 2005.07c
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    • pp.2094-2096
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    • 2005
  • In this paper, we studied the cross section analysis based on the short circuit conditions of the low voltage bare wires. The copper wires prepared for the experiment were 1.2mm 1.6mm and 2.0mm in diameter. Through the cross section analysis(CSA), it was confirmed that the dendrite structure grew at the angle of about $40^{\circ}$ or $60^{\circ}$ when the fusing current was applied to the wires. The larger the fusing current is, the more decreased the growth angle of the dendrite structure is. It was confirmed that the dendrite structure was arranged like the columnar structure. In this paper, the characteristics analysis of short circuit was carried out in the range of transient duration.

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Association between the use of electronic cigarettes and the prevalence of chronic rhinosinusitis and allergic rhinitis: a nationwide cross-sectional study

  • M.-S. Rha;H.-J. Cho;J.-H. Yoon;C.-H. Kim
    • Journal of Rhinology
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    • v.60 no.1
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    • pp.20-28
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    • 2022
  • Background: Whether the use of electronic cigarettes (ECs) is associated with upper airway diseases, including chronic rhinosinusitis (CRS) and allergic rhinitis (AR), remains unclear. Methods: We analyzed data from the nationwide cross-sectional surveys: the Korea National Health and Nutrition Examination Survey VI (2013-2015), VII (2016-2018), and VIII (2019). Logistic regression analysis was performed to assess the association between EC use and CRS or AR. Results: Among a total of 38,413 participants, 6.4% were former EC users and 2.5% were current EC users. Former EC users and current EC showed a significantly increased OR for CRS or AR compared with never EC users. In the subgroup analysis, the "current CC (conventional cigarette)-current EC" and the "current CC-formal EC" group had a significantly higher OR for CRS or AR than the "current CC-never EC" group. In addition, former CC smokers who currently use ECs showed a significantly higher OR for AR than former CC smokers without EC use. Conclusions: EC use is significantly associated with a high prevalence of CRS and AR in the adult population. These results indicate that the use of ECs may increase the risk of upper airway disease.

A Study on the Characteristics of Short Circuit through the Cross Section Analysis of Electric Wire (전선의 단면분석을 통한 단락특성에 관한 연구)

  • Shong, Kil-Mok;Choi, Chung-Seog;Kim, Yun-Hoi;Kim, Sang-Hyeon;Park, Nam-Kyu
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2005.05a
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    • pp.51-56
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    • 2005
  • For a fire cause judgement this paper describes the short circuit characteristics of a electric wire through the cross section analysis under ac condition. The cower wires prepared for the experiment were 1.2mm, 1.6mm, and 2.0mm in diameter. Through the cross section analysis(CSA), it was confirmed that the dendrite structure grew at the angle of about $40^{\circ}\;or\;60^{\circ}$ when the fusing current was applied to the wires. The larger the fusing current is, the more decreased the growth angle of the dendrite structure is. It was confirmed that the dendrite structure was arranged like the columnar structure. In this paper, the characteristics analysis of short circuit was carried out in the range of transient duration and the correlation constant k was investigated by measuring the short circuit duration and the fusing current.

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