Filter design using data fusion for a pneumatic control valve

This paper presents a filter design technique for a pneumatic valve using data fusion techniques. The objective of this paper is to examine the suppression of the effect of parameters causing deviation from normal system performance using the technique of data fusion over time. The output of a system affected by inherited noise is processed by applying operations such as finding the statistical variance, time warping, interpolation, and extrapolation. These techniques are used to compute the transfer function of the filter, which when cascaded with the system will suppress the effect of noise on the process. The operation of the control valve is affected by characteristics such as stiction, structural deformation, etc. The characteristics of the system are studied and data for multiple time instances are extracted to carry out fusion across time by dynamic time warping. Tests show that the filter presented here can suppress the effects of stiction and mechanical deformation on the output signal.

Experimental assessment of harmonic contributions using a ternary pulse sequence

Harmonic contributions of utility and customer may feature significant variations due to network switchings and changing operational modes. In order to correctly define the impacts on the grid voltage distortion the frequency dependent impedance characteristic of the studied network should be accurately measured in the real-time mode. This condition can be fulfilled by designing a stimuli generator measuring the grid impedance as a response to injected interference and producing time-frequency plots of harmonic contributions during considered time interval. In this paper a prototype of a stimuli generator based on programmable voltage source inverter is developed and tested. The use of ternary pulse sequence allows fast wide-band impedance measurements that meet the requirements of real-time assessment of harmonic contributions. The accuracy of respective analysis involving impedance determination and calculation of harmonic contributions is validated experimentally using reference characteristics of laboratory test set-up with varying grid impedance.

Energy benchmarking in educational buildings in the city of Kragujevac - possibilities for energy efficiency improvement

The implementation of energy efficiency measures and use of renewable energy sources in educational buildings can significantly contribute to reducing energy consumption, but also to CO2 emissions in the entire public sector. The paper shows the comparison of energy consumption indicators for 61 elementary school buildings which have previously been divided in 12 groups, according to the period of construction and size, based on the national typology called TABULA, as the first step of further study on how to use the renewable energy sources. The aim of this paper is to use the energy benchmarking process to select representative facilities which are suitable for applying renewable energy sources, for their further energy efficiency improvement. Indicators of annual specific electricity consumption and CO2 emissions per unit area [kWh/m2] and per user [kWh/user] were calculated. After that, from two groups (in which the highest electricity consumption and CO2 emissions are 68.37% and 74.53% of the total consumption/ emissions), one representative facility was selected.

Design and analysis of dual dumbbell and rectangular slots SIW cavity-backed antenna at 2.45 GHz

The design and realization of a wideband substrate-integrated waveguide (SIW) cavity-backed slot antenna operating at 2.45 GHz for WLAN applications are presented. Dual dumbbell-shaped slots with rectangular slots are used to achieve increased bandwidth. The bandwidth observed is 160 MHz with the dumbbell-shaped slots. Further, it has been improved up to 9.2% by adding a rectangular slot. The wideband antenna is analyzed using ANSYS HFSS and fabricated on FR-4 substrate. The measured results of the proposed design are in good agreement with the simulation results and comparable with the reported results.

Application of metaheuristic optimization algorithms for image registration in mobile robot visual control

Visual Servoing (VS) of a mobile robot requires advanced digital image processing, and one of the techniques especially fitting for this complex task is Image Registration (IR). In general, IR involves the geometrical alignment of images, and it can be viewed as an optimization problem. Therefore, we propose Metaheuristic Optimization Algorithms (MOA) for IR in VS of a mobile robot. The comprehensive comparison study of three state-of-the-art MOA, namely the Slime Mould Algorithm (SMA), Harris Hawks Optimizer (HHO), and Whale Optimization Algorithm (WOA) is presented. The previously mentioned MOA used for IR are evaluated on 12 pairs of stereo images obtained by a mobile robot stereo vision system in a laboratory model of a manufacturing environment. The MATLsoftware package is used for the implementation of the considered optimization algorithms. Acquired experimental results show that SMA outperforms HHO and WOA, while all three algorithms perform satisfactory alignment of images captured from various mobile robot poses.

Video coding and constant quality evaluation using 4k aomenc-AV1 and rav1e-AV1 formats

It is much expected from the relatively novel, open, royalty-free AV1 (Alliance for Open Media (AOMedia) Video 1) standard. At this moment, there are many new variants of AV1 format. It is designed for efficient video internet delivery and high-quality video transmission. AV1 is recognized as Google?s VP9 format successor. One of the reference tools used so far for testing AV1 is libaom- AV1. Nevertheless, due to its time-consuming performance, there are now different available standalone solutions for experimental analysis. Here, one such solution AOMedia?s standalone aomenc (aomenc-AV1) is tested in order to analyze quality assessment based on constant quality constraint factor. Three different metrics are calculated for various 4k video content of the same frame rate. Moreover, rav1e implementation was tested for the same visual data, where rav1e-AV1 also represents an AV1 video encoder, which is considered reliable and suitable in most cases, where libaom is not applicable. In this paper, the comparison results between aomenc-AV1 and rav1e-AV1 are shown.

Effect of adaptive line enhancement filters on noise cancellation in ECG signals

Power line interference is the main noise source that contaminates Electrocardiogram (ECG) signals and measurements. In recent years, adaptive filters with different approaches have been investigated to eliminate power line interference in ECG waveforms. Adaptive line enhancement filter is a special type of adaptive filter that, unlike other adaptive filters, does not require a reference signal and has potential application in ECG signal filtering. In this paper, a selflearning filter based on an adaptive line enhancement (ALE) filter is proposed to remove power line interference in ECG signals. We simulate the adaptive filter in MATLwith a noisy ECG signal and analyze the performance of algorithms in terms of signal-to-noise ratio (SNR) improvement. The proposed algorithm is validated with Physikalisch-Technische Bundesanstalt (PTB) ECG signals database. Additive white gaussian noise is added to the raw ECG signal. Influential parameters on the ALE filter performance such as filter delay, the convergence factor, and the filter length are analyzed and discussed.

Modelling and optimising a new hybrid ad-hoc network cooperation strategy performance using genetic algorithm

The lifetime of an ad-hoc network depends on a mobile device?s limited battery capacity. In ad-hoc multi-hop communication, source nodes use intermediate nodes as a relay to communicate with remote destinations. As cooperation between nodes is restrained by their battery resources, it might not be in their best interests to always accept relay requests. Therefore, if all nodes decide how much energy to spend for relaying, selfish or non-cooperative nodes reduce cooperation by rejecting to forward packets to others, thereby leading to a dramatic drop in the network?s throughput. Three strategies have been founded to solve this problem: tit-for-tat, live-and-let-live, and selective drop. This research explored a new strategy in ad-hoc cooperation which resulted from the combination of the live-and-let-live and selective drop strategies. This new strategy is based on the suggestion to select fewer hops with a low drop percentage and sufficient power to stay alive after forwarding the data packets towards the destination or other relays at the route path. We used a genetic algorithm (GA) to optimise the cooperative problem. Moreover, the fitness equation of the GA population was designed according to the mixing of the two strategies, which resulted in a new optimized hybrid dynamic-static cooperation.

Experimental indoor validation of weak intensity fluctuations over free-space optical communication link

In this paper, we present experimental results for characterizing turbulence phenomena in free-space optical (FSO) communication under laboratory controlled conditions. Collected data is used for statistical determination of the probability density function (PDF) of irradiance signal fluctuations. In literature, there are a number of empirical models for variety of turbulence regimes. Thus, obtained PDF is compared with selected models from the bibliography in order to describe properly statistical properties of real turbulent channel and help improving of FSO system performance calculation. In overall, analysis has shown that the results obtained under given constraints fit well with the exponentiated Weibull turbulence model.

End-effector Cartesian stiffness shaping - sequential least squares programming approach

Control of robot end-effector (EE) Cartesian stiffness matrix (or the whole mechanical impedance) is still a challenging open issue in physical humanrobot interaction (pHRI). This paper presents an optimization approach for shaping the robot EE Cartesian stiffness. This research targets collaborative robots with intrinsic compliance - serial elastic actuators (SEAs). Although robots with SEAs have constant joint stiffness, task redundancy (null-space) for a specific task could be used for robot reconfiguration and shaping the stiffness matrix while still keeping the EE position unchanged. The method proposed in this paper to investigate null-space reconfiguration's influence on Cartesian robot stiffness is based on the Sequential Least Squares Programming (SLSQP) algorithm, which presents an expansion of the quadratic programming algorithm for nonlinear functions with constraints. The method is tested in simulations for 4 DOF planar robot. Results are presented for control of the EE Cartesian stiffness initially along one axis, and then control of stiffness along both planar axis - shaping the main diagonal of the EE stiffness matrix.