Speech coding systems for mobile communication have to cope with noisy channels. In particular, vector quantization as central data reduction scheme is highly sensitive to transmission errors due to the low redundancy in the encoded data. Here we present three methods for the design of a vector quantizer with enhanced robustness against transmission errors. First the optimization of the index a...

In this chapter we introduce the fundamental concepts behind the Green Function Theory. We start from a description of the second quantization method and then, after introducing the ensemble average of an operator, we define the main object of the theory, the Green function. Further on, after obtaining the equation of motion for the Green function, we introduce the self-energy operator and we d...

In the given paper a method of the parameter quantization in speech coder on basis of human auditory model is presented. Output speech parameters of the coder are three sinusoidal parameters: amplitude, frequency and phase. For amplitude and frequency quantization we propose to use a vector quantization, and for phases – scalar quantization. This parameter quantization method allows to achieve ...

Delivery of video in the presence of bandwidth constraints is one of the most important video compression problems. In this work, the preprocessing for video compression is started by extracting any video format into raw data format and applying float wavelet transform on each frame. This step provides the video frames to perform an adaptive quantization in a frequency domain. This leads to red...

In this paper energy bands and Berry curvature of graphene was studied. Desired Hamiltonian regarding the next-nearest neighbors obtained by tight binding model. By using the second quantization approach, the transformation matrix is calculated and the Hamiltonian of system is diagonalized. With this Hamiltonian, the band structure and wave function can be calculated. By using calculated wave f...

We examine the general conditions for the existence of the complex structure intrinsic in the Gupta-Bleuler quantization method for the specific case of mixed first and second class fermionic constraints in an arbitrary space-time dimension. The cases d = 3 and 10 are shown to be of prime importance. The explicit solution for d = 10 is presented.