Edmar C. Gurjão

Complete software defined RFID system using GNU radio

In this paper we describe a complete Radio Frequency Identification (RFID) system, reader and tag, using the approach of software defined radio (SDR). We use the open source GNU Radio development toolkit to implement this SDR. The advantage of this approach is the possibility of to implement and test RFID applications using a flexible software platform. RFID readers in SDR have already been developed by others researchers, and our main contribution is the implementation of an RFID tag in accordance with EPC Gen2 RFID standard. The system is evaluated and it shown that it works with good performance, and as an example of application we implemented a cryptography protocol proposed to RFID.

An IEC 61850 network simulator

The IEC 61850 standard inserted new paradigms on communication between power system protection equipments. In this new environment the involved engineers need to learn new concepts. One way to help engineers in learning these concepts is using a simulator. In this context, this paper presents the main characteristics and functionalities of an IEC 61850 network simulator which is being developed by Federal University of Campina Grande (UFCG) and Hydro Electric Company of San Francisco (Chesf), an utility company of Brazil.

Television channel spectrum sensing using independent component analysis

Spectrum reuse has been proposed as a method to solve frequency bands scarcity. Detection of unused channels in a given frequency band is the main problem to reuse the spectrum. Various methods are proposed in the literature to perform this spectrum sensing. In this study, the authors apply independent component analysis (ICA) to estimate the available bands in the TV band spectrum when analogue and digital TV channels are in operation. Each component recovered by ICA is in a specific frequency band, then the other bands are considered free to reuse, that is, the absence of transmitters in a channel means there are unused bands. A measurement setup was implemented to validate the use of ICA as a spectrum detection method. The results also show the feasibility of using ICA for wideband spectrum sensing with low computational costs.

Radar cross-section and electric field analysis of backscattering elements of chipless RFID tag

Radio identification (RFID) systems based on chipless tags, outperforms traditional RFID systems in terms of costs, and the actual challenge in the former systems is to improve the quantity of bits written in a tag. Actually, the main information encoding technique is based on the generation of a particular signature in the spectrum of the backscattered signal. Chipless tags based spectral signature encode data using resonant structures, to work like band reject filters, designed to resonate at certain frequencies. Information is written as a combination of nulls in the frequency domain. Based in the idea of simultaneously use the horizontal and vertical polarization of an antenna, in this paper we analyze the radar cross-section (RCS) and electric field of elements of chipless RFID tags based on biostatic RCS. Using electromagnetic simulation software for electric field and RCS analysis, it was observed that it is possible to write data to improve the number of bits using two simultaneous polarizations.

The Safety Requirements Decomposition Pattern

Safety requirement specifications usually have heterogeneous structures, most likely based on the experience of the engineers involved in the specification process. Consequently, it gets difficult to ensure that recommendations given in standards are considered, e.g., evidence that the requirements are complete and consistent with other development artifacts. To address this challenge, we present in this paper the Safety Requirements Decomposition Pattern, which aims at supporting the decomposition of safety requirements that are traceable to architecture and failure propagation models. The effectiveness of the approach has been observed in its application in different domains, such as automotive, avionics, and medical devices. In this paper, we present its usage in the context of an industrial Automated External Defibrillator system.

Using synchronism pulse to improve A2I implementations

The necessity of the same signal for measurement and reconstruction of sparse signals in Compressed Sensing is one of the challenges in its practical implementation. In this paper, we extend the Random Modulator Pre-Integrator (RMPI), architecture proposed to signal acquisition in Compressed Sensing, by including a synchronization signal that permits to obtain the same measurement signal from a Pseudo Random Binary Sequence (PRBS), both at measurement and reconstruction, with low increase hardware complexity. The proposed extension was validated in hardware, and it is shown the possibility of transparent modification of the measurement signal, maintaining the functionality of to obtain the same signal at measurement and recovery.

A Model for Architecture Centric Development of Automated External Defibrillators

Due to complex safety requirements, medical devices must obey rigorous standards. In the development of these devices, modeling techniques must be used to analyze the design decisions in agreement with such standards. In this paper, we present a Matlab/Simulink specification as an analytical model for Automated External Defibrillators (AEDs) and its integration with a Model Based Systems Engineering (MBSE) approach through descriptive models. The proposed model allows us to analyze algorithms for decision of shock application, performance of circuits when obtaining the required voltage, safety of the produced energy for shock delivery and characteristics of signals produced at the output of the AED. The model is composed of modules with interfaces specification, allowing safe module replacement and the assessment of the module influence over the system at a technical level.

Influence of measurement matrix characteristics in a configurable analog-to-information converter performance

Analog to Information Converters (AIC) acquires a discrete representation of a signal from the analog domain in Compressed Sensing. One of the crucial point in the AIC design is the configuration of the measurement matrix. Depending of its characteristics, this matrix can degrade the AIC performance. In this paper we analyze the influence of the primitive polynomial choice to configure a Linear Feedback Shift Register, that generates the measurement matrix values, in the performance of a configurable AIC. It is shown that, depending of the chosen primitive polynomial with a certain degree, the performance of the AIC can be completely degraded.

Influence of integrators in the performance of analog-to-information converters

The development of analog-to-information converter if one the challenges in Compressed Sensing. In architectures proposed in the literature, the presence of integrators is a crucial point to the conversion. Hardware implementation of the integrators have great influence in the AIC performance, and using simulation in this work we analyze the AIC performance when some integrator parameters change. It was observed that there is a relation between cutoff frequency and AIC performance and depending on the value of this frequency low values of measurement occurs, and a high gain is necessary, what is a problem in hardware implementations.

Analysis of parameters for jamming separation in GPS signals using Independent Component Analysis

The Global Positioning System (GPS) is a worldwide service and it is used as a reference for many other time, altitude, latitude and longitude based systems. Intentional jammers can degrade the reception of GPS signals, causing the receivers to fall out of sync. The technique employed in Independent Components Analysis (ICA) provides the ability to separate the interference (jamming). In this paper, we analyze the influence of ICA parameters in the convergence and effectiveness of the method when applied to separate the GPS signal from the jamming from the received signal.