Maja Lutovac

Automated knowledge–based filter synthesis using modified Legendre approximation and optimisation of summed sensitivity

The paper presents the automated design of active RC and programmable filters. The approximating function is derived using Legendre orthogonal polynomial with the appropriate weights and usage of two Legendre multiplication factors at the origin and the pass–band edge frequency. Detailed analysis is done for the frequency response and sensitivity analysis of active RC filters. Optimisation is performed using symbolic manipulation of expressions inputted into computer algebra system and numeric solvers. The code is in the form of template notebook, and the user should specify the minimal number of numeric values, such as the number of second–order filter sections, the pass–band edge frequency, the reflection coefficient, and the preferred values of component values.

Electronic tour guide for Android mobile platform with multimedia travel book

In this paper, a new system for positioning and multimedia reporting, named electronic tour guide, is presented. The mobile device of the system communicates with the server, from which it receives electronic tourist maps, and the GPS satellites. Each location on the map with predetermined irregular shape avoids overlap with other areas and thus it increases the accuracy of the visited location. The device is guiding the tourist using the coordinates received from the GPS signals and the objects that are preloaded as electronic maps. The main functions of the system are: (a) it is displaying the content according to users movement, position and preferred selections; (b) it generates reports for guiding using existing date stored from the server, the current position, the previous movement and the paid services; (c) it reports and prepares the multimedia travel book based on the paid services; (d) it prepares the daily trip report from images, text and audio files downloaded from server or recorded by user; (e) it submits the recorded data for future individual, group or public usage. This paper presents the main characteristics and advantages of the new system as well as benefits for commercial usage.

Efficient recursive implementation of multiplierless FIR filters

The efficient implementation of selective multiplierless digital FIR filter is very desired solution for low-power consumption applications. Filter requirements such as sharp transition and large stop-band attenuation require very high filter order and usually large power consumption. The solution of this problem can be to use predefined hardware filter structures with small number of operations per input sample in spite of the very high filter order. In this paper we provide a systematic approach for solving the problem using computer algebra system (CAS). The methodology is based on (1) sketching the filter structure that is known to have excellent properties appropriate as embedded solution, (2) automated building the knowledge into CAS in a form of the schematic description, (3) automated derivation of filter properties such as transfer functions or implementation codes, (4) defining a strategy for combining intermediate results, and (5) plotting the frequency responses in order to verify the final solution.

Virtual robot in distributed control system

Before the development of robotic systems, it is of great importance to perform verification of various types of scenarios within the machine work and testing. That is especially important in designing the machine with new control logic, before releasing the machine. This paper describes 3D simulator, as part of the offline system, within distributed system for robot control. It is developed in Lola Institute and it provides robot control and monitoring. Parts of the developed system communicate via CORBA protocol, allowing remote control of the robot system through an intuitive graphical user interface.

Automated proving properties of expectation-maximization algorithm using symbolic tools

In many analysis based on estimation the parameters of probability distribution functions, the algorithms are developing for unknown probabilities. Some algorithms are derived starting from previous solutions and algorithms. One very popular algorithm is the EM (Expectation-Maximization) algorithm. The EM algorithm is a starting point for developing other advanced algorithms. Features of EM and other algorithms are observed with the traditional numerical approach. In this paper, we present a new approach of analysis EM algorithm using symbolic processing (specific Mathematica). We automatically derive properties of the algorithm. The knowledge embedded in the symbolic expressions was used to simulate an example system and EM algorithm to generate the implementation code of some critical parts of analysis.

Design of symmetric lossless LC filter with analysis of critical element changes

The paper presents the design of analog filter based on a new class of all-pole approximation. The approximating function is derived using Legendre orthogonal polynomial with the appropriate weights and the usage of two Legendre multiplication factors (at the origin and at the passband edge frequency). The design procedure is illustrated on LC ladder filter (inductors L, capacitors C) and analysis of the critical element changes of the 11th-order filter. The whole process of the design and optimization is automated using software Mathematica.

Remote control of industrial robot lola 50 using wireless communication and android device

Android platform based devices are powerful mobile computers with a rich variety of built-in sensors and permanent Internet connectivity. Because of its powerful capabilities, as well as open architecture, they became promising candidates for a number of industrial applications. This paper describes the process of implementation and use of application for remote control of industrial robot Lola 50, in manual mode, using the Android mobile phone and wireless communication.

A proposed approach to the classification of bearing condition using wavelets and random forests

This paper presents a proposed approach to the classification of rolling element bearing faults. The approach consists of vibration signal acquisition, digital signal processing, feature extraction from the vibration signal and classification into functional or defective rolling element bearing. Digital signal processing includes signal decomposition and de-nosing using wavelets. An 18-dimensional vector of the vibration signal feature is obtained as a result of feature extraction. Characterization of each recorded vibration signal is performed by a combination of signals time varying statistical parameters and characteristic rolling element bearing fault frequency components. The classification is performed using random forests algorithm.

3D simulator for human centrifuge motion testing and verification

In the process of defining commands and developing algorithms for movements of complex and massive devices, such as human centrifuge, it is unsafe and demanding to perform testing on the real machine. Getting overview of devices operations might be of great importance especially before the final realization. This paper presents a system for programming and simulation of the human centrifuge motion with integrated 3D motion simulator. The simulator is used for verification of newly defined motion commands and testing the new algorithms for the human centrifuge motion.

Effects of finite pole accuracy on element values of LC ladder filters

The paper presents the design of analog filter based on known poles of all-pole approximation. The design procedure is illustrated on several LC ladder filter and have an effect on of the element tolerances of L and C. The whole process of the design and optimization is automated using computer algebra system — software Mathematica.