Budimir Lutovac

Are genetic algorithms useful for the parameter estimation of FM signals

The estimation of polynomial-phase signals (PPSs) is a multiparameter problem, and the maximum likelihood (ML) optimization functions have numerous local optima, making the application of gradient techniques impossible. The common solution to this problem is based on the phase differentiation (PD) techniques that reduce the number of dimensions but, at the same time, reduce the accuracy and generate additional difficulties such as spurious components and error propagation. Here we show that genetic algorithms (GAs) can serve as a powerful alternative to the PD techniques. We investigate the limits of accuracy of the ML technique, and of some alternatives such as the high-order cubic phase function (HO-CPF) and high-order Wigner distribution (HO-WD). The ML approach combined with the proposed GA setup is limited up to the fifth-order PPS, which is not sufficient in many applications. However, the HO-CPF and HO-WD techniques coupled with the GA are able to accurately estimate phase parameters up to the tenth-order PPS. They significantly improve the accuracy with respect to the high-order ambiguity function (HAF) and product HAF (PHAF) and, for higher-order PPSs, they are much simpler and more efficient than the integrated generalized ambiguity function (IGAF).

An algorithm for robust image watermarking based on the DCT and Zernike moments

An image watermarking scheme in the 2D DCT domain is proposed by exploring the advantages of using Zernike moments. Zernike transform has been used in image processing applications such as image recognition, authentication, protection, etc. Here, we propose to use the Zernike moments of the DCT transform to provide an efficient watermarking method. Particularly, the novelty of the proposed approach relies on the method for selection of features that will enable both preserving the image quality and robustness to attacks. Also, a criterion for selection of image blocks suitable for watermarking is given. It is based on the ℓ1-norm of Zernike moments. The efficiency of the proposed watermarking algorithm is proved on several examples considering different types of attacks (compression, noise, filtering, geometrical attacks).

Some electromechanical systems and analogies of mem-systems integer and fractional order

This paper will provide some an applications of memristors and mem-systems with a particular focus on electromechanical systems and analogies that holds great promise for advanced modeling and control of complex objects and processes. Also, we present the connection between fractional order differ integral operators and behavior of the mem-systems. Finally, several potential applications of electromechanical analogies of integer and fractional order are discussed.

Analysis of electrical circuits including fractional order elements

This paper deals with the analysis of electrical circuits with classical one-port elements including two novel defined one-port fractional order elements: fractional-order resistive-capacitive RC-α and fractional-order inductive RL-α element. The definitions and analytical relations between current, voltage and power of introduced fractional elements are provided. An example of fractional element realization via ladder electrical circuit composed of classical resistors, capacitors and/or inductors is presented. Several examples are analyzed to illustrate the behavior of electrical circuit with fractional order elements for different values of fractional order α including differentiator/integrator circuits as well as complex circuits without accumulated energy.

A cloud computing architecture with wireless body area network for professional athletes health monitoring in sports organizations — Case study of Montenegro

High physical, psychological and economic cost of sports injuries are the reason that lead to the recognition of a need for having a system to monitor health parameters of a professional athlete hence preventing incidences of severe injuries. Athletes in any sports can greatly benefit from feedback from the systems for improving the quality of their training. In this paper, we present architecture for a cloud based system which incorporates wearable motion sensors to obtain information on health parameters of sports athlete and provide feedback to the sports clubs and sports organization in Montenegro. The sensors are placed on athletes body at predefined positions which may capture the movements, heart rate, ECG and respiratory data. Advances in wireless technology and supporting infrastructure provide opportunity for real-time healthcare and fitness monitoring without constraining the activities of the user. Wirelessly connected sensors placed in, on, and around the body form a body area network for continuous and unobtrusive monitoring of health parameters of professional sports athletes.

Proposal of an ICT solution for monitoring of types of sports injuries in sports organizations — Case study of Montenegro

Institute for Sports and Sports Medicine of Montenegro has undertaken a research to determine the state of health of athletes in Montenegro, and led to a clear insight in the state of the health care of athletes in sports clubs and federations. The conclusion to which research led was that the implementation of health protection was left to the federations and clubs, but it is directly dependent on the financial situation in them. In this paper we compare the current system on flow and storage of information on injuries in sports clubs and federations and we propose the improvement of this system through proposal of new ICT solution that hence would lead to a information system. Offered solution would greatly relieve collection, transfer and evaluation and monitoring of sports injuries, and hence with this type of data a valid source for statistical analysis of types of injuries of professional athletes in clubs in Montenegro.

Elliptic biquadratic sections using second generation current conveyors (CCIIs)

In this paper we propose a new, programmable, easy-tunable, current-mode general-purpose Biquad (C-GP-B), using second-generation current conveyors (CCIIs), based on the well-known direct form II, which, among other transfer functions, is also suitable to realize band-rejection (BR) or notch transfer function. It is convenient for elliptic transfer function realizations because it can realize finite transfer function zeroes. Since it has low sensitivity and grounded capacitors it is suitable for integrated circuit (IC) design. The new Biquad is then compared in sensitivity performance with other two CCII-based versions of biquadratic sections obtained by different approaches. Since all presented Biquads use CCIIs they operate in the current mode, and are therefore suitable to realize filter circuits operating at higher frequencies, consuming less power, and needing lower supply voltage. As an example, the design procedure, and the Monte Carlo sensitivity analysis using PSpice were performed for a fourth-order elliptic low-pass (LP) filter.

Algebraic Design of Some Equiripple Linear-Phase Half-Band FIR Filters

Summary A closed form solution for the approximation of a linear-phase FIR (finite impulse response) filter with equiripple magnitude responsein the passband and stopband was not known. In this letter we present a closed form solution of some equiripple linear-phase half-band FIR filter approximation.

A resistive circuits analysis using graph spectral decomposition

A method for a resistive circuit analysis based on graph spectral decompositions is proposed. It is shown that the Laplacian matrix can be used in order to calculate node potentials. Based on the Laplacian eigenvalues and eigenvectors it is possible to decompose a complex resistive circuit into smaller, weakly connected sub-circuits.

On the fixed-point rounding in the DFT

Rounding error in the discrete Fourier transform calculated with fast fixed-point algorithms is considered. It is shown that the variance of the rounding error depends on frequency index. Theoretically obtained results for error variance are statistically checked on decimation-in-time fast Fourier transform with two rounding methods.