ABSTRACT. Recently, microwave imaging has been envisioned as an important complimentary tool in medical diagnostics, besides golden standards in this field, such as CT scan and MRI. However, in order to achieve performances that qualify this technology to be translated from research bench to patient bedside, we need advanced 3D EM simulation environment. As a base for such environment we started from commercial general purpose 3D EM solver WIPL-D Pro and its CAD variant. In addition we added libraries of a) tissue properties, b) antenna models c) models of the antenna arrays/systems, d) models of parts of human body (phantoms), and e) scenarios that combine antennas and phantoms to emulate practical usage of microwave imaging devices. Special procedures/new options are developed to enable easy creation and fast and accurate analysis of new libraries’ components. The effectiveness of such 3D EM simulation environment will be illustrated on a number of practical examples.

ABSTRACT. This paper considers the experimental shielding effectiveness analysis of an enclosure with a metal plate placed at a certain angle inside. Dimensions of a metal plate are determined to affect the enclosure’s first resonant frequency in order to improve its protective function. A metal plate impact inside measured enclosure on the shielding effectiveness values especially at the first frequency as well as at the whole frequency range is presented.

ABSTRACT. This paper presents a numerical technique for characteristic impedance and effective relative permittivity calculation of the system of two-wire line and a dielectric plate. The hybrid boundary element method is used to compute those parameters. The quasi-static TEM analysis is applied. Two different plate positions are analysed. Computed results are given for different parameters values. In order to verify the accuracy of the method, the analysed systems are also modelled using FEMM software. The calculated hybrid boundary element method results are well coincident with those obtained using the FEMM.

ABSTRACT. Electrostatic discharges (ESD) consequences are not only damages, but also very fast transients in electric circuits and devices, as well as in large power systems. This paper presents frequency spectrum analysis of the IEC 61000-4-2 standard current approximated by multi-peaked analytically extended function (MP-AEF) and of typical lightning currents according to the IEC 62305 standard. This analysis is important for the choice of protective devices and frequency range of measurement equipment used in experiments. A comparison of the measured and theoretical results is also given.

ABSTRACT. Real-time Location Systems (RTLS) are important technology utilized to provide spatial and temporal location information to Industry 4.0 systems. We discuss in more details ultra-wide band radio frequency identification systems (WB RFID). We proposed utilization of visualization and data analytics techniques to quantify and examine latencies and availability and demonstrated their potential usages in a large scale environment. The proposed methodology could easily be extended to other RTLS systems with similar configuration.

ABSTRACT. In 5th generation (5G) wireless networks high levels of spectral and energy efficiency, reliability and connectivity have to be maintained. Moreover, the ever-increasing requirements for high data rates and low latency, especially when ultra-reliable communications are envisaged, lead to the need for profound examination of wireless technologies and how to improve them. Additionally, from the physical layer perspective, the various types of modulation recently proposed for 5G networks will have the ability to offer well-controlled low levels of interference and reduced Out-of-Band (OOB) leakage, thus maintaining high spectral efficiency. In this paper, the pulse shaping approach implemented through prototype filters with flexible numerology in Filter Bank Multicarrier (FBMC) is studied in Vehicle-to-Infrastructure (V2I) communications characterized by high delay spreads and high velocities of the User Equipment (UE). The key benefits of FBMC technology over Orthogonal Frequency Division Multiplexing (OFDM) in 5G networks are discussed and the impact of flexible numerology-based FBMC on overall network performance is investigated.

ABSTRACT. This paper investigates quasi-logarithmic (QL) quantizers with two approaches: first is for constant variance σ2=1 and second is switched QL quantizer, that implies splitting the variance range into subranges and designing a separate quantizer for each of them. For both approaches our goal is to design the optimal quantizer with predetermined mean coding bit rate, i.e. to find the quantizer parameters that lead to the highest Signal-to-Quantisation-Noise-Ratio (SQNR).

ABSTRACT. This paper presents an implementation of noise removal from a color image using bilateral filter and wavelet transform based on dual core Blackfin microcontrollers. The tasks organization between the two cores and calculus optimizations are illustrated in a framework for image processing. The obtained results show that the proposed framework can be successfully used to achieve a real time implementation for noise removal in video clips for medium size images.

ABSTRACT. Procedure for analysis of measurement uncertainty of signal generator, applicable in the process of testing the devices for measurement of standard electrical power quality parameters, is described in this paper. This specific analysis includes influence of typical quality disturbances in generated signals on total measurement uncertainty values. Evaluation of individual measurement uncertainty components, including the total uncertainty budget, is performed according to document Guide to the Expression of Uncertainty in Measurement. In the paper is presented the experimental measurement system for evaluation of measurement uncertainty of software based signal generator. Calibration is performed using reference calibrator Fluke 5500A. Digital multimeter Keithley 2010 is applied for the measurement of generator output voltage values. Total budget of measurement uncertainty components for this signal generator includes the calculation of standard measurement uncertainty of Type A and Type B, combined measurement uncertainty value and expanded measurement uncertainty of signal generator.

ABSTRACT. Article describes a method for automating measurement and characterization of electrical materials at high frequency. For measurement and characterization are used LCR meter for measuring material parameters as function of frequency and furnace for testing electrical materials at different temperature. For the measurement and characterization of electrical materials, an application was developed that automates the control of the measuring system. Based on this it has been shown that measurement of material characteristics can be performed without the presence of a human factor. For testing the method, doped BaTiO3 ceramic samples are used.

ABSTRACT. The paper presents the results from the research for randomness of 8 pseudo random bit generators (PRBGs) for short sequences (256, 512 and 1024 bits) – Linear Feedback Serial Registers (LFSRs) with 8, 9, 16, 21 bits and different taps, Galois, Kasami, Gold and Mersenne-Twister (used in MATLAB). The goal is to determine the best PRBGs for telecommunications implementations for which randomness is critical as Analog-to-Information Converters (AICs) based on compressive sensing, where the recovery of the signal samples at under-Nyquist rate uses a random bit sequence. The PRBGs are tested with 10 tests from NIST suite for randomness which are applicable for short sequences. The PRBGs passing the tests are implemented in a laboratory set-up of AIC for obtaining the solution with the highest Signal-to-Noise and Distortion (SINAD).

ABSTRACT. This paper presents an approach to solve multi-objective Flexible Job Shop Scheduling problems (FJSSP) combining a heuristic algorithm with Promethee I solutions ranking. The formulated FJSSP includes four objectives (criteria). Pair-wise comparisons of criteria values are used to arrange the obtained non-dominated solutions. The proposed methodology gives a possibility for better quality evaluation of considered solutions and reduces very much the efforts of Decision Maker (DM) in the choice of preferred final compromise solution.

ABSTRACT. Computer vision can recognize the shape of an object but it is unable to see inside of the object and determine the properties of the material. With development of UWB radars it is possible to see under the skin of observed object. In this paper, we propose using low cost commercial Ultra-Wide Band (UWB) modules for material identification that are, basically, designed for localization in wireless sensor networks. These modules are capable of measuring RF impulse response of a channel (in this case the channel is the observed material) and, from the response, it is possible to classify materials using Machine Learning.

ABSTRACT. Future ground to deep space communication systems should support Gbps data links, which are resilient to atmospheric impairments. An alternative and in the same time complementary to the conventional RF technology is the emerging deep space Free Space Optical (FSO) system, which can successfully face the challenge. Aligned with this future possibility, the current paper reports on a performance of the deep space FSO system based on detailed simulations considering single-photon communication scenario. Among the several available optical receiver units, a state of the art Superconducting Nanowire Single Photon Detector (SNSPD) technology is implemented. The SNSPD is characterized with a quantum efficiency, dead time, dark count rate and number of channels. The investigation is based on the Poisson channel and well-known Pulse Position Modulation (PPM) deployed as a modulation technique. Moreover, the selected receiver aperture diameter provides the necessary resilience to atmospheric turbulence effect. Addressing the sophisticated parameterization of the current simulations, BER performance of the deep space FSO link based on the SNSPD receiver is provided. On the top of it, an output of the SNSPD in RF domain is considered. The sequence of RF output pulses is presented before and after the applied ideal low-pass filter.

ABSTRACT. In this paper a method of recognizing images using an embedded platform is proposed. The target images are particularly represented by traffic signs but, in the future, the application will be generalized. The actual literature presents various ways of achieving traffic signs recognition, but most of them are computational expensive and others cannot recognize the signs in low light condition or in a noisy setup. For this study, an embedded platform from Nvidia (Jetson TX2) was used along with a low-cost webcam. Classical algorithms like SURF (Speeded Up Robust Features), SIFT (Scale Invariant Feature Transform) or ORB (Oriented fast and Rotated Brief) offer reliable results when the lighting condition between the reference image and the image obtained from the camera are similar. In our setup, the algorithms mentioned above start to behave badly in low light conditions. Therefore, this paper discusses the possibility of using HAAR like features alongside a classifier for detecting traffic signs.

ABSTRACT. In this paper a performance analysis of an High Frequency Surface Wave Radar (HFSWR) in a typical equatorial environment is presented. Statistical properties of HFSWR working environment (noise/clutter) and targets statistical properties are analyzed and mathematically modeled. Based on derived statistical functions and desired HFSWR performances regarding probability of false alarm, few different probability of detection are calculated. Despite very harsh working environment it is shown that good performances can be achieved. Data used for this evaluation is obtained from HFSWR sites located in the Gulf of Guinea.

ABSTRACT. In this paper an analysis of effects originating from a transmitter of one High-Frequency Over-the-Horizon radar (HF-OTHR) on its own range performance is presented. The model used for this analysis is based on measured values of system parameters, which allows obtaining realistic results in simulation analysis. This model is described and explained, along with the format of observed data and simulation results in the meaning of impact of transmitter’s parameters on system’s overall performance. The influence of these critical parameters, namely the output power level and the level of the internal noise within the power amplifier, to the range estimation of HF-OTH radars is quantified for all seasons over the year, in general and under the terms of specific geographical location.

ABSTRACT. In this paper a few implementations of Doppler processing in High Frequency Surface Wave Radar (HFSWR) signal processing are examined. All of them are based on sequential Fast Furier Transform (FFT), but differ in so called “window” functions used for preparation of the data before the final FFT. Three different sets of magnitudes of weights used to form Hamming, Blackman and Blackman-Harris window functions will be evaluated in this paper. In this paper an optimal window function is chosen for the given situation. Data used for this evaluation is obtained from HFSWR sites located in the Gulf of Guinea.

ABSTRACT. We present an integration of elevation correction algorithm with Singular Value Decomposition (SVD) based surface reflected wave removal algorithm for ground penetrating radar (GPR) systems positioned above ground with elevation variation. The GPR system and the experimental environment are simulated using the gprMax open-source software. The simulated scenario can be used for GPR mounted on Unmanned Aerial Vehicle (UAV), e.g. drone. The results show excellent reduction of both the effect of terrain with elevation variation and the effect of the surface reflected wave, increasing the probability of object detection, especially when the targets are low-reflective objects. The improved detection capability is tested using Faster-RCNN network, which shows the effectiveness of the method.

ABSTRACT. We investigate an implementation of a compressive sampling (CS) stepped frequency ground penetrating radar. Due to the small number of targets, the B-scan is represented as a sparse image. Due to the nature of stepped frequency radar, smaller number of random frequencies can be used to obtain each A-scan (sparse delays). Also, the measurements obtained from different antenna positions can be reduced to a smaller number of random antenna positions. We also use the structure in the B-scan, i.e. the shape of the targets, which can be known, for instance, when detecting land mines. We demonstrate our method using radar data available from the Web from the land mine targets buried in the ground. We use group sparsity, i.e. we assume that the targets have some non-zero (and presumably known) dimension in the cross-range coordinate of the B-scan. For such targets, we also use the Markov chain model for the targets, where we simultaneously estimate the model parameters using the EMturboGAMP algorithm. Both approaches result in improved performance.

ABSTRACT. The vision of the fifth generation (5G) mobile systems can be conceived as a highly manageable networking environment that provides increased performance while supporting a variety of services with widely diverse requirements. In order to realize the above vision, network slicing has been proposed as a resource provisioning technique capable to meet these requirements with reduced operating costs, while opening new horizons for network efficiency. The aim of the Network Slice Selection Function (NSSF) is selecting the set of network instances serving the users, based on localized configuration, and other relevant information including radio access networks (RANs) performances in the registration domain. In this paper, NSSF based on Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) is proposed. Here, the network slices are considered as alternatives, and their performances indicators are contemplated as the criteria for decision making. The influences of various weighting techniques, including entropy, standard deviation, and variance, are analyzed through rank reversal phenomenon and computational complexity.

ABSTRACT. Network slicing enables deployment of multiple virtual networks customized to different service and users using the same physical infrastructure. Network slice selection information may be configured in User Equipment (UE) and may be dynamically provided by the network. The paper presents an approach to open access to the slice update which enables applications deployed at Radio Access Network (RAN) to assist the UE in network slice selection during mobility management procedures. The application-based slice selection may consider the RAN congestion level and current radio conditions.

ABSTRACT. Virtualization and softwarization are key concepts in fifth generation (5G) system design. 5G core network adopts service-oriented architecture which provides agile and flexible platform for diverse use cases. The paper presents an approach to design Radio Access Network (RAN) control plane functions as micro services. The approach improves the interoperability as core network service can interact with RAN services in uniform way The focus is on User Equipment Context Management procedures which are defined as a RESTful service.

ABSTRACT. This paper presents solution for transmission of Q-SIG messages over IP network without a loss in Q-SIG capabilities. SIP is used to tunnel Q-SIG messages over IP network. Special attention is given to analysis of jitter and echo impact on voice transmission in the presented solution. Parameter settings of jitter buffer and echo canceller are analyzed and proposed in this paper. Real-life network is used to test the presented solution and proposed parameter settings of jitter buffer and echo canceller.

ABSTRACT. Mobile Ad hoc NETworks (MANETs) are widely used in everyday life. Evaluation of MANETs performances can be a complicated task since it involves complex technology and mobile network nodes. Network Simulator-3 (NS-3) is an open source simulator popular in the research community for wireless network simulation. In the current release of NS-3, there is no suitable universal tool for the estimation of parameters such as throughput, packet loss ratio, end-to-end delay, jitter, and others, which are necessary for MANET performance evaluation. Therefore, we have developed an extension of NS-3 that is easy to use and provides efficient network performance analysis. In order to evaluate proposed implementation, a series of simulations of one MANET network scenario within the Dynamic Source Routing (DSR) protocol is done, and simulation results are presented. The source code of the developed tool is publicly available.

ABSTRACT. With the advent of Internet of Things (IoT) applications requiring massive streaming data collections, the need for new cloud databases has risen. This work focusses on the implementation of an end-to-end system from real-time data collection to real-time prediction. The storage system is implemented on the International Business Machines (IBM) cloud platform using the Cloudant NoSQL database service. The prediction algorithm is implemented in JAVA using the Devops Insights service together with a web interface and an android mobile application. The system demonstrates rapid real-time prediction when deployed on the IBM cloud platform as well as real-time storage capabilities.

ABSTRACT. Real-time Internet based video communication applications are becoming widely adopted by internet users. However, the exponentially rising numbers of internet users is proving to be a real challenge to guarantee a good Quality of Service (QoS) for such applications. This paper investigates how video streaming quality is impacted by the increasing number of users using a video streaming application developed with Web Real Time Communications (WebRTC). The application considers both live video streaming from of an event captured by the initiator’s webcam and live streaming of a video file from the initiator’s device. Tests were performed using a Wi-Fi connection with different types of video sources. Moreover, equal cost load balancing was used to assess the impact on the video quality two servers are used at the initiator’s site. Videos were recorded for five minutes on both the initiator and client sides using the application’s record function and the Peak Signal to Noise Ratio (PSNR) was used to assess the quality of the videos. Results showed that with equal cost load balancing using two servers a maximum gain of up to 5.39 dB in PSNR could be obtained with live streaming from a webcam to ten clients.