Now showing items 1-20 of 10426

    • Effect of feedback carrier excitation on LED external quantum efficiency 

      Author: Kučera, L.; Macháč, J.; Míšek, J.
      (IEEE, 1982-02)
      Self-absorption of photons generated by prior luminescence processes affects both the steady-state and transient characteristics of LEDs. In this study we confine ourselves to one of the most important steadystate ...
    • Static model of DH laser 

      Author: Macháč, J.
      (IEEE, 1983-04)
      A method of complex analysis of the double-heterostructure stripe-geometry laser, based on a new static model, is presented. The optical field distribution in the active region of the laser is described by the wave equation. ...
    • Fluxgate sensor with increased homogeneity 

      Author: Ripka, Pavel; Jireš, František; Macháček, Milan
      (IEEE, 1990-09)
      Several types of fluxgate sensors were developed for measuring microvariations of the earth's magnetic field. Sensor cores were produced by etching, leading to better geometric homogeneity and long-term stability. This ...
    • Analysis of discontinuities in waveguiding structures by MAB method 

      Author: Macháč, J.
      (IEEE, 1992-08)
      The method of minimal autonomous blocks (MAB) is briefly described. A universal code computing reflectivity and transmissivity of discontinuities in waveguide structures was developed on the basis of the MAB method. This ...
    • On the design of waveguide-to-microstrip and waveguide-to-coplanar line transitions 

      Author: Macháč, Jan; Menzel, Wolfgang
      (IEEE, 1993-09)
      New versions of the waveguide-to-microstrip and waveguide-to-coplanar line transitions are described and analyzed. The transitions differ from the standard ones by a probe in the shape of a rectangular patch. The structure ...
    • Waveguide bandpass filters with attenuation of higher-order passbands 

      Author: Menzel, Wolfgang; Macháč, Jan
      (IEEE, 1993-09)
      A new method is proposed to provide additional attenuation to higher-order passbands of metal waveguide bandpass filters. To this end, shunt waveguide sections with cut-off frequencies are included into the filter structure. ...
    • Short and Open Circuited Slot Line 

      Author: Macháč, Jan; Zehentner, Ján; Menzel, Wolfgang
      (IEEE, 1995-07)
      A slot line terminated by the short and open end is analysed by the spectral domain method (SDM). The original process of Yang and Alexopoulos (1988) is modified by application of the piecewise sinusoidal functions only. ...
    • Load Impedances of Complex Slotline Terminations 

      Author: Macháč, J.; Zehentner, J.; Menzel, W.
      (IEEE, 1995-09)
      Single slotline has gained new interest due to application in uniplanar circuits, antennas or active radiators, all these including slotline short circuits or even more complex terminations. This paper gives a new approach ...
    • Leakage Effects of Dominant and Higher Order Modes on Slotline 

      Author: Macháč, Jan; Zehentner, Jan
      (IEEE, 1996-09)
      The properties of the slotline when the dominant bound or leaky wave propagates, together with the behaviour of new higher order modes are investigated. The frequency range in which the slotline transmits the bound wave ...
    • Using grammars for scene interpretation 

      Author: Christensen, H.I.; Matas, J.; Kittler, J.
      (IEEE, 1996-09)
      A method that employs grammars to direct the inference process of a vision system that does interpretation of dynamic scenes is described. The system uses a set of qualitative image descriptors to drive the interpretation. ...
    • Conditions that Force an Orthomodular Poset to Be a Boolean Algebra 

      Author: Tkadlec, Josef
      We introduce two new classes of orthomodular posets—the class of weakly Boolean orthomodular posets and the class of orthomodular posets with the property of maximality. The main result of this paper is that the ...
    • Upper Cut-Off Frequency of the Bound Wave and New Leaky Wave on the Slotline 

      Author: Zehentner, Ján; Macháč, Jan; Migliozzi, Maurizio
      (IEEE, 1997-06)
      This paper contributes to a more profound understanding of uniplanar circuit behaviour. A simple closed-form formula providing the upper cut-off frequency of the bound wave propagating over the slotline is presented. A new ...
    • Evolution of New Real and Complex Improper Solutions of the Slotline Dispersion Equation 

      Author: Zehentner, J.; Macháč, J.; Migliozzi, M.
      (IEEE, 1997-09)
      An attempt is made in this paper to reach a better understanding of the behaviour of open uniplanar circuits, particularly the slotline. A new second leaky wave has been revealed in addition to the dominant bound and leaky ...
    • Concrete Quantum Logics with Generalised Compatibiliy 

      Author: Tkadlec, Josef
      We present three results stating when a concrete (= set-representable) quantum logic with covering properties (generalization of compatibility) has to be a Boolean algebra. These results complete and generalize some ...
    • On Combining Classifiers 

      Author: Kittler, Josef; Hatef, Mohamad; Duin, Robert P.W.; Matas, Jiří
      (IEEE, 1998-03)
      We develop a common theoretical framework for combining classifiers which use distinct pattern representations and show that many existing schemes can be considered as special cases of compound classification where all the ...
    • Performance of the slotline in the mm-wave range 

      Author: Zehentner, Ján; Macháč, Jan; Migliozzi, Maurizio
      (IEEE, 1998-05)
      This paper deals with an investigation of the dispersion characteristics of the slotline in the mm-wave range. Attention is paid to the possible excitation of the surface leaky waves on the slotline. Higher order leaky ...
    • Dispersion characteristics of leaky waves on lossless and lossy slotlines 

      Author: Zehentner, Ján; Macháč, Jan; Migliozzi, Maurizio
      (IEEE, 1998-06)
      This paper deals with the dependence of the type of solution of the determinantal slotline dispersion equation on the location of the poles of its matrix elements. A number of possible solutions above the cut-off frequencies ...
    • Fluxgate: Tuned vs. Untuned Output 

      Author: Ripka, Pavel; Billingsley, S.W.
      (IEEE, 1998-07)
      Fluxgate voltage output contains information about the measured DC magnetic field in amplitude of even harmonic components. Tuning the sensor output causes the concentration of output energy to specific harmonics (usually ...
    • Selection of Speaker Independent Feature for a Speaker Verification System 

      Author: Pandit, M.; Kittler, J.; Matas, J.
      (IEEE, 1998-08)
      In this paper we propose an optimisation technique to choose a user independent feature subset from the input feature set for a dynamic time-warping (DTW) based text-dependent speaker verification system. The results ...