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doc. Ing. Lukáš Vojtěch, Ph.D.

All publications

Evaluation of Electrolytically Manufactured Copper Foils Properties

  • DOI: 10.1109/ISSE57496.2023.10168520
  • Link: https://doi.org/10.1109/ISSE57496.2023.10168520
  • Department: Department of Electrotechnology, Department of Telecommunications Engineering
  • Annotation:
    This paper deals with electrolytically manufactured copper foils prepared under different manufacturing conditions. The main goal is to evaluate mechanical and electrical properties concerning the further use of foils for flexible applications in the electronics industry. Four samples of copper foil were prepared using an electrolytic manufacturing process, with different compositions of the electrolyte (Cu2+=50g/1, H2SO4=70g/1, Cadditives=0,5m1/1, and Cu2+=50g/1, H2SO4=70g/1, Cadditives=1m1/1) and different properties of cathodes (shiny stainless steel and roughened stainless steel, sanded with 1000 grit sandpaper). The current density was 1 A/dm2. The mechanical properties like elongation at break, modulus of elasticity in tension, tensile strength, and hardness were evaluated. The electrical conductivity of manufactured copper foils was also evaluated. The results show that the properties of copper foils were affected not only by changes in electrolyte composition (concentration of additives), but also by the roughness of cathodes (the higher roughness increased the effective surface of the cathode). The electrolytically prepared copper foils were compared with commercially available foil prepared by the metallurgical rolling process. The commercial sample exhibited similar electrical conductivity, lower hardness and higher modulus of elasticity in tension.

Resource Efficient Real-time Reliability Model for Multi-Agent IoT Systems

  • DOI: 10.1109/ACCESS.2021.3138931
  • Link: https://doi.org/10.1109/ACCESS.2021.3138931
  • Department: Department of Telecommunications Engineering
  • Annotation:
    Rising demand for the integration of IoT services in cloud computing has brought cloud- native principles (e.g., system automation, loosely coupled services, etc.) to the edge of the network. A fundamental element of the cloud-native approach is a microservice — an instance, which is usually virtualised, serving for only a defined purpose. Virtualised microservices are mostly used in cloud-based IoT systems, which can be covered with multi-agent system (MAS) paradigm. The maintenance of a MAS requires a constant monitoring to track the system state and to satisfy the service level agreement (SLA) (or any other) requirements. This paper presents a resource efficient reliability model for MAS IoT systems for monitoring purposes. First, we provide a thorough mathematical analysis to describe the generic system model and its elements. This model takes into account SLA requirements and it is characterised with linear time complexity, simplicity of computations and input metrics (e.g., combination of SLA for CPU and its workload), where all of the input data are aligned to the same range. Then, we evaluate time complexity and provide a measurement to demonstrate the reliability of the model application. The results show that the proposed model is efficient for large number of the IoT agents. It is approximately 98 times faster in AQ:4 computation with 1,000 systems and 51 times faster in computations with 1,000 systems.

Simulation of Radio Signal Propagation for UHF RFID Technology in an Indoor Environment Using Ray Tracing (Graphics) Method

  • DOI: 10.3390/app122111065
  • Link: https://doi.org/10.3390/app122111065
  • Department: Department of Telecommunications Engineering
  • Annotation:
    RFID systems are often used in industry to reduce costs, increase process efficiency and minimize human intervention. The challenge is to design an RFID system before it is implemented in a specific environment in the shortest possible time and at minimum cost while maintaining the accuracy of the results. In this paper, a new approach to predicting indoor UHF RFID signal coverage is presented. It is based on a graphical ray tracing method. Simulations are performed based on spatial analysis of the illumination of a 3D indoor environment created from a 2D floor plan. The results show a heat map representing the predicted RSSI radio signal levels using a color range. The approach is validated by comparison with the results of the empirical Multi-Wall model. The time complexity of the approach is presented. The proposed approach is able to generate a heat map with the accuracy of the empirical Multi-Wall model. The interior room equipment required to refine the results ought to be investigated in the future.

LoRa as a complement to the existing access system infrastructure

  • Department: Department of Telecommunications Engineering
  • Annotation:
    Wireless Sensor Networks (WSN) play an important role in the Internet of Things (IoT). For smart buildings, they provide a convenient way to collect data from sensors and control electronic devices in and around buildings. This paper describes a solution in which the existing access system infrastructure, based on the RS485 protocol, is extended by the LoRa wireless sensor network, sensor nodes for temperature and humidity measurement and the LoRa communication gateway. Operational measurements on one floor of the CTU in Prague block show that depending on the data rate used in the RS485 network and the data rate reserve used, which precedes the failure of the access system control function, it is possible to operate tens to hundreds of sensor nodes simultaneously transmitting their data. The results show that WSN can be used effectively in the existing RS485 infrastructure.

Methodology of Studying Effects of Mobile Phone Radiation on Organisms: Technical Aspects

  • DOI: 10.3390/ijerph182312642
  • Link: https://doi.org/10.3390/ijerph182312642
  • Department: Department of Telecommunications Engineering
  • Annotation:
    The negative influence of non-ionizing electromagnetic radiation on organisms, including humans, has been discussed widely in recent years. This paper deals with the methodology of examining possible harmful effects of mobile phone radiation, focusing on in vivo and in vitro laboratory methods of investigation and evaluation and their main problems and difficulties. Basic experimental parameters are summarized and discussed, and recent large studies are also mentioned. For the laboratory experiments, accurate setting and description of dosimetry are essential; therefore, we give recommendations for the technical parameters of the experiments, especially for a well-defined source of radiation by Software Defined Radio.

Auto-ID Technology and the Internet of Things to Enhance the Quality of Health Services U-Health Concept

  • Authors: Unucka, J., Staša, P., Beneš, F., Švub, J., doc. Ing. Lukáš Vojtěch, Ph.D., Ing. Marek Neruda, Ph.D., Urban, P.
  • Publication: 2020 IEEE 2nd Eurasia Conference on Biomedical Engineering, Healthcare and Sustainability (ECBIOS). Piscataway: IEEE, 2020. p. 137-140. ISBN 978-1-7281-8712-9.
  • Year: 2020
  • DOI: 10.1109/ECBIOS50299.2020.9203630
  • Link: https://doi.org/10.1109/ECBIOS50299.2020.9203630
  • Department: Department of Telecommunications Engineering
  • Annotation:
    Health care facilities are subject to high demands on the optimization of the management of medicines and medicaments, resulting inter alia from the requirements of the Joint Accreditation Commission. These demands depend primarily on the quality of the personnel and the ability to prevent errors due to human factors. By meeting these requirements and adhering to them, healthcare facilities will achieve accreditation of the quality of care provided. The whole concept is based on utilization of Auto-ID and Internet of Things technology which brings new opportunities for healthcare sector. To ensure a high standard of care with U-Health concept, we developed e.g. new type of bed that respect the concept of Auto-ID and IoT. This type of bed is equipped with a newly developed intelligent mattress with integrated sensor of surface loading, which enables timely preventive warning when the change of the position is needed.

Evaluation of Electrical Properties of Metalized Woven and Non-woven Polymer-Based Textiles

  • DOI: 10.1109/ISSE49702.2020.9120943
  • Link: https://doi.org/10.1109/ISSE49702.2020.9120943
  • Department: Department of Electrotechnology, Department of Telecommunications Engineering
  • Annotation:
    The smart textiles seem to be a very interesting possibility in many industrial fields e.g. medicine, automotive, textile industry etc. These types of textile are mainly based on metalized threads. It is necessary to know the physical characteristics of smart textiles before their use for a specific application. This article deals with the preparation and characterization of three types of textiles - copper-coated non-woven polyamide fabric and copper and nickel coated woven polyester fabric. Characterization was based on the measurement of textiles properties like the thickness of metallization, electrical resistance. The measurements of thickness metallization were done at micro-section by electron microscopy. The electrical resistance was evaluated for further usage of these fabrics as a heating system in smart textiles, where a low resistance of the heating part is desirable. The sheet resistance was measured in different directions to obtain information about the isotropic or anisotropic character of samples. The highest electrical resistance had woven copper-coated polyamide fabrics. The anisotropic character of samples was more obvious for woven polyester fabrics.

Fuzzy Logic Based Indoor Localization Using WLAN Infrastructure

  • DOI: 10.1109/ECBIOS50299.2020.9203711
  • Link: https://doi.org/10.1109/ECBIOS50299.2020.9203711
  • Department: Department of Telecommunications Engineering
  • Annotation:
    The paper introduces a method and system for real-time positioning of mobile terminals in indoor areas. The system uses wireless LAN infrastructure (usually Wi-Fi) and evaluates signal strength from different access points. The system meets requirements and has been implemented in Java for Android-based mobile devices and successfully tested at the Centre for Assistive Technologies (CAT) at the Czech Technical University in Prague, Faculty of Electrical Engineering. The results demonstrate an average accuracy of approximately 2.5 m, which is satisfactory for determining the position of a client device at room-level (e.g. in hospitals for checking whether a patient or staff member is currently in an expected place or for deciding where they can be assigned). Its potential applications are in healthcare, disaster management, supervision of people with disabilities, etc., but also in monitoring staff and goods in closed areas.

Indoor Positioning System based on Fuzzy Logic and WLAN Infrastructure

  • DOI: 10.3390/s20164490
  • Link: https://doi.org/10.3390/s20164490
  • Department: Department of Telecommunications Engineering
  • Annotation:
    This paper deals with the issue of mobile device localization in the environment of buildings, which is suitable for use in healthcare or crisis management. The developed localization system is based on wireless Local Area Network (LAN) infrastructure (commonly referred to as Wi-Fi), evaluating signal strength from different access points, using the fingerprinting method for localization. The most serious problems consist in multipath signal propagation and the different sensitivities (calibration) of Wi-Fi adapters installed in different mobile devices. To solve these issues, an algorithm based on fuzzy logic is proposed to optimize the localization performance. The localization system consists of five elements, which are mobile applications for Android OS, a fuzzy derivation model, and a web surveillance environment for displaying the localization results. All of these elements use a database and shared storage on a virtualized server running Ubuntu. The developed system is implemented in Java for Android-based mobile devices and successfully tested. The average accuracy is satisfactory for determining the position of a client device on the level of rooms.

Experimental load test statistics for the selected IPS tools on low-performance IoT devices

  • DOI: 10.2478/jee-2019-0058
  • Link: https://doi.org/10.2478/jee-2019-0058
  • Department: Department of Telecommunications Engineering
  • Annotation:
    The goal of this paper is to propose a testing procedure for selected Intrusion Prevention Systems (IPS) in a realistic network traffic in terms of their suitability on a given hardware microcomputers for low-performance devices for Internet ofThings (IoT). We perform an IPS research in terms of resource usage in order to establish a universal procedure of checking,whether a given microcomputer controlling IoT devices (often in overloaded state) can additionally burden the installation and start-up of IPS. The experiment is repeated on several boards under overload condition to determine the maximum data rate, above which transmission degrades. The presented testing method is an exemplary tool for IoT applications concerning the security of embedded devices with low performance.

Real-Time Localization of Transmission Sources by a Formation of Helicopters Equipped with a Rotating Directional Antenna

  • DOI: 10.1007/978-3-030-14984-0_25
  • Link: https://doi.org/10.1007/978-3-030-14984-0_25
  • Department: Department of Telecommunications Engineering, Multi-robot Systems
  • Annotation:
    This paper proposes a novel technique for radio frequency transmission sources (RFTS) localization in outdoor environments using a formation of autonomous Micro Aerial Vehicles (MAVs) equipped with a rotating directional antenna. The technique uses a fusion of received signal strength indication (RSSI) and angle of arrival (AoA) data gained from dependencies of RSSI on angle measured by each direc- tional antenna. An Unscented Kalman Filter (UKF) based approach is used for sensor data fusion and for estimation of RFTS positions during each localization step. The proposed method has been verified in simula- tions using noisy and inaccurate measurements and in several successful real-world outdoor deployments.

Autonomous System for UHF RFID Signal Measurement in Industrial Environment

  • Authors: Švub, J., Staša, P., Beneš, F., doc. Ing. Lukáš Vojtěch, Ph.D., Ing. Marek Neruda, Ph.D., Brožek, T.
  • Publication: The Proceedings of the 2018 11th IFIP Wireless and Mobile Networking Conference (WMNC). Laxenburg: International Federation for Information Processing, 2018. p. 81-86. ISSN 2163-4033. ISBN 978-3-903176-03-4.
  • Year: 2018
  • DOI: 10.23919/WMNC.2018.8480906
  • Link: https://doi.org/10.23919/WMNC.2018.8480906
  • Department: Department of Telecommunications Engineering
  • Annotation:
    Deployment of UHF RFID technology in the industrial environment is not easy to perform because of the heterogeneity of the environment, the propagation of the high frequency radio signal, the interference, and the associated timeconsuming implementation. The paper deals with deployment and evaluation of developed autonomous system for measurement of UHF RFID signals in industrial environment. Such a system allows, in defined 3D real-world locations, to obtain autonomously information about the actual Received Signal Strength Indicator of the moving RFID tag (Etalon) that is registered while investigated with each antenna of RFID reader. A corridor was chosen as an experimental area, and Received Signal Strength Indicator was evaluated by both, simulation and measurement methods. The results show a statistically significant relationship between measured and modeled Received Signal Strength Indicator in dBm at the 99% confidence level. The presented autonomous system can contribute to a more comprehensive analysis of measuring the electromagnetic field emitted by the UHF RFID antennas in various industrial environments.

Electrode Shapes and Frequency Band Analysis for Human Body Communication

  • Authors: Hnyk, P., Kvarda, L., doc. Ing. Lukáš Vojtěch, Ph.D., Ing. Marek Neruda, Ph.D., Zitta, T.
  • Publication: Proceedings of the 2018 18th International Conference on Mechatronics - Mechatronika (ME) 2018. Brno: Brno University of Technology, Faculty of Mechanical Engineering, 2018. p. 360-365. ISBN 978-80-214-5544-3.
  • Year: 2018
  • Department: Department of Telecommunications Engineering
  • Annotation:
    Geometric shapes of electrodes for channel optimization of Human Body Communication (HBC) are presented. Effective energy coupling between signal electrodes and the human body is described in deep. The influence of transmitting distance of HBC channel, ground leakage, human body composition, surrounding environment, geometric shapes and contact of the electrodes with the body on capacitive coupling is discussed. Selected geometric shapes of electrodes are developed, measured and compared for its effectiveness. The key finding of the research is that the best shape for capacitive coupling (CC-HBC) electrode is the octagon, and dynamic carrier frequency change.

Electromagnetic Shielding Effectiveness of Woven Fabrics with High Electrical Conductivity: Complete Derivation and Verification of Analytical Model

  • DOI: 10.3390/ma11091657
  • Link: https://doi.org/10.3390/ma11091657
  • Department: Department of Telecommunications Engineering
  • Annotation:
    In this paper, electromagnetic shielding effectiveness of woven fabrics with high electrical conductivity is investigated. Electromagnetic interference-shielding woven-textile composite materials were developed from a highly electrically conductive blend of polyester and the coated yarns of Au on a polyamide base. A complete analytical model of the electromagnetic shielding effectiveness of the materials with apertures is derived in detail, including foil, material with one aperture, and material with multiple apertures (fabrics). The derived analytical model is compared for fabrics with measurement of real samples. The key finding of the research is that the presented analytical model expands the shielding theory and is valid for woven fabrics manufactured from mixed and coated yarns with a value of electrical conductivity equal to and/or higher than σ = 244 S/m and an excellent electromagnetic shielding effectiveness value of 25–50 dB at 0.03–1.5 GHz, which makes it a promising candidate for application in electromagnetic interference (EMI) shielding.

Multi-Channel Access to Improve QWL in Health Care Services - Infrastructure Based QoS Ensurance in IoT

  • DOI: 10.23919/ELMAR.2018.8534645
  • Link: https://doi.org/10.23919/ELMAR.2018.8534645
  • Department: Department of Telecommunications Engineering
  • Annotation:
    We propose a multi-channel access to improve Quality of Work Life in health care services and Quality of Service in the Internet of Things with suitably chosen infrastructure. The demo of the proposed solution of multi-channel communication system is realized for the hospital cleaning staff. The Quality of Work Life is improved by exactly described procedures of work plan and the Quality of Service is improved by redundant transmission channels and technologies, following the scenario and service strategy.

Penetration Testing of Intrusion Detection and Prevention System in Low-Performance Embedded IoT Device

  • Authors: Zitta, T., Ing. Marek Neruda, Ph.D., doc. Ing. Lukáš Vojtěch, Ph.D., Matějková, M., Jehlička, M., Hach, L., Moravec, J.
  • Publication: Proceedings of the 2018 18th International Conference on Mechatronics - Mechatronika (ME) 2018. Brno: Brno University of Technology, Faculty of Mechanical Engineering, 2018. p. 387-391. ISBN 978-80-214-5544-3.
  • Year: 2018
  • Department: Department of Telecommunications Engineering
  • Annotation:
    The penetration testing method of provided security protection by IDS/IPS (Intrusion Detection System / Intrusion Prevention System) tool Suricata in the lowperformance embedded IoT device is presented. Penetration testing tools are presented with emphasis on software tools, such as NMAP and Metasploit. The used testing method is described in deep. IDS/IPS tool Suricata is implemented in embedded platform Raspberry Pi 3. Main contribution is the implemented testing method for Suricata IPS that can be used in other applications of security rules of embedded IoT devices.

Surface Area Evaluation of Electrically Conductive Polymer-Based Textiles

  • DOI: 10.3390/ma11101931
  • Link: https://doi.org/10.3390/ma11101931
  • Department: Department of Electrotechnology, Department of Telecommunications Engineering
  • Annotation:
    In this paper, the surface area of coated polymer-based textiles, i.e., copper and nickel plated woven polyester fabric, copper and acrylic coated woven polyester fabric, and copper and acrylic coated non-woven polyamide fabric, is investigated. In order to evaluate the surface area of the woven fabrics, Peirce’s geometrical model of the interlacing point and measurement using an electron microscope are used. Non-woven fabrics are evaluated using an optical method, handmade method, and MATLAB functions. An electrochemical method, based on the measurement of the resistance between two electrodes, is used for relative comparison of the effective surface area of the coated woven and non-woven fabrics. The experimental results show that the measured and calculated warp lengths do not differ within the standard deviation. The model for the surface area evaluation of the Pierce’s geometrical model for monofilament (non-fibrous) yarns is extended to multifilament yarns and to a uniform sample size. The experimental results show the increasing trend of surface area evaluation using both modeling and electrochemical methods, i.e., the surface area of the copper and acrylic coated woven Polyester fabric (PES) is the smallest surface area of investigated samples, followed by the surface area of the copper and acrylic coated non-woven fabric, and by copper and nickel plated woven PES fabric. These methods can be used for surface area evaluation of coated polymer-based textiles in the development of supercapacitors, electrochemical cells, or electrochemical catalysts.

Novel approach to shopping experience

  • Authors: Benes, F., Svub, J., Stasa, P., Bohm, J., doc. Ing. Lukáš Vojtěch, Ph.D.,
  • Publication: MobiQuitous 2017: Proceedings of the 14th EAI International Conference on Mobile and Ubiquitous Systems: Computing, Networking and Services. New York: Association for Computing MachineryNew York, 2017. p. 525-526. ISBN 978-1-4503-5368-7.
  • Year: 2017
  • DOI: 10.1145/3144457.3144516
  • Link: https://doi.org/10.1145/3144457.3144516
  • Department: Department of Telecommunications Engineering
  • Annotation:
    The paper discusses the possibilities of radio frequency identification technology for identification objects in defined space and thus determine customer's behavior. This paper aims to analyze current methods of detecting movement and behavior of customer in the st ore area and to achieve the greatest automation possible with more accurate, faster processes of increased quality. The proposed system will collect a large amount of operational data, one of the objectives will also be to transform this data into information and extract the greatest possible amount of knowledge. The experiments described in this paper demonstrate feasibility and possibility of solution enabling tracking of objects in a given area.

Object localization for determining customer’s behavior: Auto-ID based approach

  • Authors: Benes, F., Stasa, P., Svub, J., Unucka, J., doc. Ing. Lukáš Vojtěch, Ph.D.,
  • Publication: MobiQuitous 2017: Proceedings of the 14th EAI International Conference on Mobile and Ubiquitous Systems: Computing, Networking and Services. New York: Association for Computing MachineryNew York, 2017. p. 468-477. ISBN 978-1-4503-5368-7.
  • Year: 2017
  • DOI: 10.1145/3144457.3145505
  • Link: https://doi.org/10.1145/3144457.3145505
  • Department: Department of Telecommunications Engineering
  • Annotation:
    The paper discusses the possibilities of radio frequency identification technology for identification objects in defined space and thus determine customer's behavior. This paper aims to analyze current methods of detecting movement and behavior of customer in the st ore area and to achieve the greatest automation possible with more accurate, faster processes of increased quality. The proposed system will collect a large amount of operational data, one of the objectives will also be to transform this data into information and extract the greatest possible amount of knowledge. The experiments described in this paper demonstrate feasibility and possibility of solution enabling tracking of objects in a given area.

Software Implementation of Secure Firmware Update in IoT Concept

  • DOI: 10.15598/aeee.v15i4.2467
  • Link: https://doi.org/10.15598/aeee.v15i4.2467
  • Department: Department of Telecommunications Engineering
  • Annotation:
    This paper focuses on a survey of secure firmware update in the Internet of Things, design and description of safe and secure bootloader implementation on RFID UHF reader, encryption with AES-CCM and versioning with use of external backup flash memory device. In the case of problems with HW compatibility or other unexpected errors with new FW version, it is possible to downgrade to previous FW image, including the factory image. Authentication is provided by the UHF RFID service tag used to extract unique initialization vector of the encryption algorithm for each update session. The results show slower update speed with this new upgrade method of approximately 27% compared to older one, using the only AES-CBC algorithm.

The security of RFID readers with IDS/IPS solution using Raspberry Pi

  • DOI: 10.1109/CarpathianCC.2017.7970418
  • Link: https://doi.org/10.1109/CarpathianCC.2017.7970418
  • Department: Department of Telecommunications Engineering
  • Annotation:
    This paper presents developed detection rules for LLRP (Low Level Reader Protocol) interface, implementation of IDS (Intrusion Detection System) and IPS (Intrusion Prevention System) solution for UHF (Ultra High Frequency) RFID (Radio Frequency Identification) reader using Raspberry Pi 3. Developed security solution is used for securing current RFID readers supporting LLRP. The paper also deals with a comparison of IPS/IDS solutions and subsequently selection of the appropriate one for the implementation using Raspberry Pi. Main contribution is the securing of RFID readers which are usually available without any encryption support on the market. The functionality is tested with software metasploit framework.

DoA Outdoor RFID Locator - System Verification Report

  • Department: Department of Circuit Theory, Department of Telecommunications Engineering
  • Annotation:
    The paper discusses testing the RFID locator system in real traffic in a 1 km2 area of interest for localization. Digital processing of the signal, arriving to a 20-element antenna array at the individual receiving stations, is based on the direction on arrival (DoA) method. The achieved accuracy is typically within 1 m, thus the system met its creators' expectations. The paper describes the basic operating principle of the proposed system and compares the existing outdoor localization methods. There is also a description and the results of the experimental verification of the technology at two locations, including a determination of the localization error. The key idea is to use this technology in area of security application (especially critical infrastructures) and disaster management application.

Ensuring the Visibility and Traceability of Items Through Logistics Chain of Automotive Industry Based on AutoEPCNet Usage

  • Authors: Stasa, P, Benes, F, Svub, J, Kang, YS, Unucka, J, doc. Ing. Lukáš Vojtěch, Ph.D., Kebo, V, Rhee, J
  • Publication: Advances in Electrical and Electronic Engineering. 2016, 14(4), 378-388. ISSN 1336-1376.
  • Year: 2016
  • DOI: 10.15598/aeee.v14i4.1788
  • Link: https://doi.org/10.15598/aeee.v14i4.1788
  • Department: Department of Telecommunications Engineering
  • Annotation:
    Traceability in logistics is the capability of the participants to trace the products throughout the supply chain by means of either the product and/or container identifiers in a forward and/or backward direction. In today’s competitive economic environment, traceability is a key concept related to all products and all types of supply chains. The goal of this paper is to describe development of application that enables to create and share information about the physical movement and status of products as they travel throughout the supply chain. The main purpose of this paper is to describe the development of RFID based track and trace system for ensuring the visibility and traceability of items in logistics chain especially in automotive industry. The proposed solution is based on EPCglobal Network Architecture.

Indoor Signal Propagation of LoRa Technology

  • Authors: Gregora, L., doc. Ing. Lukáš Vojtěch, Ph.D., Ing. Marek Neruda, Ph.D.,
  • Publication: Proceedings of the 2016 17th International Conference on Mechatronics - Mechatronika (ME) 2016. Prague: Czech Technical University in Prague, Faculty of Electrical Engineering, 2016. p. 476-479. ISBN 978-80-01-05883-1.
  • Year: 2016
  • Department: Department of Telecommunications Engineering
  • Annotation:
    With an increasing number of small devices, the concept of LPWANs becomes more popular. The most important requirements on LPWANs include long battery lifetime, low price of devices, ability to connect millions of devices and long range coverage; the long range coverage is the most critical issue of this technology. In this paper we discuss indoor signal propagation of LoRa technology. At the beginning of the paper, there is an introduction to LoRa technology. Later, the paper presents a measurement of an indoor propagation of LoRa signal in a reinforced concrete building in Prague, the Czech Republic. The measurement is realized with one mobile transmitter and one receiver with a fixed location for each experiment. The measurement is performed for two experiments, one with the receiver in the basement of the building, one with the receiver on the roof of the building. Results of the measurement are graphically visualized for both measurement experiments at the end of this paper and show that the best signal coverage is for the roof location, where it includes also flats of neighboring entrances.

Mobile Application for Controlling UHF RFID Reader

  • Authors: Zitta, T., Ing. Marek Neruda, Ph.D., doc. Ing. Lukáš Vojtěch, Ph.D.,
  • Publication: Proceedings of the 2016 17th International Conference on Mechatronics - Mechatronika (ME) 2016. Prague: Czech Technical University in Prague, Faculty of Electrical Engineering, 2016. pp. 471-475. ISBN 978-80-01-05883-1.
  • Year: 2016
  • Department: Department of Telecommunications Engineering
  • Annotation:
    This paper presents design and implementation of mobile application for management of UHF (Ultra High Frequency) RFID (Radio Frequency Identification) reader. Developed mobile application is used for simplify and accelerate configuration of RFID readers. The paper also deals with analysis of UHF RFID reader parameters and subsequently determination the requirements on UHF RFID readers, data networks, mobile devices and development of mobile application. Application is developed for OS Android. JAVA Library LTK (LLRPToolkit) is used for implementing LLRP (Low Level Reader Protocol) for reader management. Main benefit of this application is utilizing LLRP on Android platform which was never been done before as application utilizing LLRP is not available on Google Play Store. The functionality is checked and tested with software RiFiDi and UHF RFID readers.

RFID Locator

  • Department: Department of Electromagnetic Field, Department of Circuit Theory, Department of Telecommunications Engineering
  • Annotation:
    The RFID locator system enables identification of casualties/injured persons during mass disaster incidents in a defined area. The system processes the transmitted signals and displays the location of individual tags, which are fixed to every injured person, in real-time in detailed maps. This solution enables to optimize a procedure of rescue operations while minimizing the time required to save, even in a situation where standard communication systems are off.

Software Implementation of a Secure Firmware Update Solution in an IOT Context

  • DOI: 10.15598/aeee.v14i4.1858
  • Link: https://doi.org/10.15598/aeee.v14i4.1858
  • Department: Department of Telecommunications Engineering
  • Annotation:
    The paper presents the secure delivery of firmware updates to Internet of Things (IoT) devices. Additionally, it deals with the design of a safe and se- cure bootloader for an Ultra High Frequency Radiofrequency Identification (UHF RFID) reader. A software implementation of a secure firmware update solution is performed. The results show the implementation of the Advanced Encryption Standard (AES) encryption into existing IoT devices, e.g. UHF RFID reader, requires at least 49.7 kB of flash memory and 10 kB of RAM, and therefore there is space to integrate even more security features into existing devices without hardware upgrade.

The Issue of LPWAN Technology Coexistence in IoT Environment

  • Authors: Krupka, L., doc. Ing. Lukáš Vojtěch, Ph.D., Ing. Marek Neruda, Ph.D.,
  • Publication: Proceedings of the 2016 17th International Conference on Mechatronics - Mechatronika (ME) 2016. Prague: Czech Technical University in Prague, Faculty of Electrical Engineering, 2016. p. 480-487. ISBN 978-80-01-05883-1.
  • Year: 2016
  • Department: Department of Telecommunications Engineering
  • Annotation:
    This paper discusses Low Power Wide Area Network technologies. The purpose of this work is a presentation of these technologies in a mutual context in order to analyse their coexistence. In this work there are described Low Power Wide Area Network terms and their representatives LoRa, Sigfox and IQRF, of which characteristics, topology and some significant technics are inspected. The technologies are also compared together in a frequency spectrum in order to detect risk bands causing collisions. A potential increased risk of collisions is found around 868.2 MHz. The main contribution of this paper is a summary of characteristics, which have an influence on the resulting coexistence.

Application of Shielding Textile Materials in Electric Vehicles

  • Department: Department of Telecommunications Engineering
  • Annotation:
    New designed power systems of electric and hybrid vehicles influence other systems by generated disturbing electromagnetic field. One of the promising measures to mitigate this negative effect can be found in additional shielding of cables, which can be provided by electrically conductive textile materials. This paper focuses on verification of utilization of specifically designed shielding textile material, which are used as additional cable shielding in order to prevent undesirable effects of electromagnetic disturbance on data transmission. The results of our measurements verify that this concept provides advantageous characteristics of electrically conductive textile materials such as shielding capability, elasticity and easy handling.

Design of RFID Outdoor Localization System RFID Locator for Disaster Management

Design of Solar Harvested Semi Active RFID Transponder with Supercapacitor Storage

  • DOI: 10.15598/aeee.v13i4.1485
  • Link: https://doi.org/10.15598/aeee.v13i4.1485
  • Department: Department of Telecommunications Engineering
  • Annotation:
    This paper presents the analysis, design and manufacture of a low cost, low maintenance and long-range prototype of RFID transponder with continuous operability. A prototype of semi-active RFID transponder is produced with a range that can be extended via a DC input to allow all of the readers signal power to be reflected via backscatter modulation. The transponder is powered via solar harvested power which is selected over other energy harvesting technologies as it provides a greater energy density and lower cost. Solar has one major drawback in terms of providing a steady DC voltage in it needed a constant supply of sunlight. A method of power storage is proposed, and the use of a supercapacitor over a rechargeable battery is used as it has a longer lifespan due to higher recharge rates. The prototype underwent a series of experiments in various working environments and proves an effective solution in providing long lasting operability. The paper concludes the use of solar harvesting with supercapacitor storage has potential for further uses in external remote sensors used in the Internet of Things.

GNSS/RFID Active Transponder Design

  • DOI: 10.15598/aeee.v13i5.1384
  • Link: https://doi.org/10.15598/aeee.v13i5.1384
  • Department: Department of Electromagnetic Field, Department of Circuit Theory, Department of Telecommunications Engineering
  • Annotation:
    The paper describes a design of global navigation satellite system (GNSS)/Radio frequency identification (RFID) active transponder which is primarily designed for localization of objects as a part of localization system designated for efficient handling of situations with mass casualties. The precise localization is improved by differential GNSS. The block diagram of such GNSS/RFID active transponder is described including main operation procedures of the firmware. Measurement of the localization by algorithms of RTKLIB library and by algorithms of GNSS module is compared. Dynamic tests, i.e. GNSS/RFID active transponder placed in the moving car (50~kmph), and static tests, i.e. GNSS/RFID active transponder placed in the position for 15~min, are performed.

Outdoor Localization Technique Using Active RFID Technology Aimed for Security and Disaster Management Applications

Qualitative And Security Parameters Inside Middleware Centric Heterogeneous RFID/IoT Networks, On-Tag Approach

  • Authors: Kypus, L., doc. Ing. Lukáš Vojtěch, Ph.D., Kvarda, L.
  • Publication: 38th International Conference on Telecommunications and Signal Processing. Piscataway: IEEE, 2015. pp. 21-25. ISSN 1805-5435. ISBN 978-1-4799-8498-5.
  • Year: 2015
  • Department: Department of Telecommunications Engineering
  • Annotation:
    Work presented in the paper started as preliminary research, and analysis, ended as testing of radio frequency identification (RFID) middlewares. The intention was to get better insight into the architecture and functionalities with respect to its impact to overall quality of service (QoS). Main part of paper focuses on lack of QoS awareness due to missing classification of data originated from tags and from the very beginning of the delivery process. Method we used to evaluate did follow up on existing researches in area of QoS for RFID, combining them with new proposal from standard ISO 25010 regarding – Quality Requirements and Evaluation, system and software quality models. The idea is to enhance application identification area in user memory bank with encoded QoS flags and security attributes. The proof of concept of on-tag specified classes and attributes is able to manage and intentionally influence applications and data processing behavior.

RFID Platform as a Service, Containerized Ecosystem, Feasibility and Security Impact Analysis

  • DOI: 10.15598/aeee.v13i5.1499
  • Link: https://doi.org/10.15598/aeee.v13i5.1499
  • Department: Department of Telecommunications Engineering
  • Annotation:
    This paper presents a new concept as a special type of virtualization of particular event based communication components in RFID ecosystems. The new approach is containers based virtualization, and it is applied and tested on the container of Object name service. The results of the experiment allowed us to do the preliminary analysis of security consequences on the isolated containerized DNS-based RFID sub-service. We confirmed feasibility with this sandboxing technology represented by the special container. They bring the benefits in terms of efficient software component life-cycle management and integrity improvements. Experiments results of the containerization are discussed to show the possible isolation ways of other components like EPCis and middleware. There is present evaluation towards external threats and vulnerabilities. The result is a higher level of integrity, availability of whole ecosystem and resiliency against external threats. This gives a new opportunity to build robust RFID as Platform as a service, and it proves the ability to achieve a positive impact on the end to end service Quality of service.

Security of ONS Service For Applications of the Internet of Things and Their Pilot Implementation in Academic Network

  • DOI: 10.1109/CarpathianCC.2015.7145087
  • Link: https://doi.org/10.1109/CarpathianCC.2015.7145087
  • Department: Department of Telecommunications Engineering
  • Annotation:
    We focused mainly on the availability and confidentiality concerns in this paper. We tried to identify the hardening impact by metrics evaluating operational status, resiliency, responsiveness and performance of managed ONS solution design. Design of redundant and hardened testing environment under tests brought us the visibility into the assurance of the internal communication security and showed behavior under the load of the components in such complex information service, with respect to an overall quality of the delivered ONS service.

UHF RFID Tag Design for Disaster Management

  • Department: Department of Telecommunications Engineering
  • Annotation:
    This paper deals with the Ultra High Frequency (UHF) Radio Frequency Identification (RFID) tag design as a part of RFID localization system primarily designated for mass disasters. The design of RFID tag considers many casualties in an area of hundreds square meters, human body impedance, battery lifetime, maximal output power, resistant encapsulation etc. All requirements are taken into account in the design of several versions of RFID tag and the best one is chosen. Subsequently the design is manufactured and measured. Results show the designed RFID tag prototype is suitable for application in a disaster management.

Comparative Method for Indirect Sensitivity Measurement of UHF RFID Reader with Respect to Interoperability and Conformance Requirements

  • Authors: Kypus, L., doc. Ing. Lukáš Vojtěch, Ph.D.,
  • Publication: Advances in Electrical and Electronic Engineering. 2014, 12(4), 319-324. ISSN 1336-1376.
  • Year: 2014
  • DOI: 10.15598/aeee.v12i4.1211
  • Link: https://doi.org/10.15598/aeee.v12i4.1211
  • Department: Department of Telecommunications Engineering
  • Annotation:
    There is never-ending race for the competitive advantage that forces RFID technology service integrators to focus more on used technology qualitative aspects and theirs impacts inside RFID ecosystem. This paper contributes to UHF RFID reader qualitative parameters evaluation and assessment problematic. It presents and describes in details indirect method and procedure of sensitivity measurement created for UHF RFID readers. We applied this method on RFID readers within prepared test environment and confirmed long term intention and recognized trend. Due to regulations limitations, there is not possible to increase output power over defined limits, but there are possibilities to influence reader sensitivity. Our proposal is to use customized comparative measurement method with insertion loss compensation for return link. Beside the main goal achievement, results show as well the qualitative status of development snapshot of reader. Method and following experiment helped us to gain an external view, current values of important parameters and motivation we want to follow up on as well as compared developed reader with its commercial competitors.

FE Model of EM Shielding Textile Materials

  • DOI: 10.1109/MECHATRONIKA.2014.7018310
  • Link: https://doi.org/10.1109/MECHATRONIKA.2014.7018310
  • Department: Department of Telecommunications Engineering
  • Annotation:
    Technical textile materials can be successfully used also as a protection against external electromagnetic field. There are available technologies to improve the material surface – with use of different (galvanize, plate, etc.) technologies. The paper deals with woven textiles – compound of cotton, polyester and conductive fibers. The paper presents the impact of electromagnetic field on special woven textile materials and describes the shielding principles. The measurement technique used at FEL CTU in Prague is also described and the base measuring technologies are discussed. Nevertheless, the major part of the paper is dedicated to experience of authors with numerical (FE) modeling of shielding textiles and to description of designed and used methodology of FE model evaluation. The numerical results are compared to measurement and to mathematical (Matlab) model results.

Heating Ability of Electrically Conductive Textile Materials

  • DOI: 10.1109/MECHATRONIKA.2014.7018332
  • Link: https://doi.org/10.1109/MECHATRONIKA.2014.7018332
  • Department: Department of Telecommunications Engineering
  • Annotation:
    Electrically conductive textile materials can be successfully used also as textile conductors. Electrical heating system consists of power supply, supply conductors and the appliance which is formed by electrically conductive textile material with the ability of heat production. The paper presents modelling principles of these materials. Preparation of samples is discussed. Measurement techniques are described and the results show specific conditions for advantageous use of these materials especially in the area of medical applications.

Impact of Human Emotions on Physiological Characteristics

  • Authors: Partila, P., Vozňák, M., Peterek, T., Penhaker, M., Novák, V., Továrek, J., Mehić, M., doc. Ing. Lukáš Vojtěch, Ph.D.,
  • Publication: Proceedings of SPIE, Volume 9118. Washington: SPIE, 2014. Proceedings of SPIE. ISSN 0277-786X. ISBN 9781628410556.
  • Year: 2014
  • DOI: 10.1117/12.2050679
  • Link: https://doi.org/10.1117/12.2050679
  • Department: Department of Telecommunications Engineering
  • Annotation:
    Emotional states of humans and their impact on physiological and neurological characteristics are discussed in this paper. This problem is the goal of many teams who have dealt with this topic. Nowadays, it is necessary to increase the accuracy of methods for obtaining information about correlations between emotional state and physiological changes. To be able to record these changes, we focused on two majority emotional states. Studied subjects were psychologically stimulated to neutral - calm and then to the stress state. Electrocardiography, Electroencephalography and blood pressure represented neurological and physiological samples that were collected during patient’s stimulated conditions. Speech activity was recording during the patient was reading selected text. Feature extraction was calculated by speech processing operations. Classifier based on Gaussian Mixture Model was trained and tested using Mel-Frequency Cepstral Coefficients extracted from the patient's speech. All measurements were performed in a chamber with electromagnetic compatibility. The article discusses a method for determining the influence of stress emotional state on the human and his physiological and neurological changes.

Modelling of Conductive Textile Materials for Shielding Purposes and RFID Textile Antennas

  • DOI: 10.5755/j01.eee.20.8.8443
  • Link: https://doi.org/10.5755/j01.eee.20.8.8443
  • Department: Department of Telecommunications Engineering
  • Annotation:
    Present production of electronic devices requires gently handling with raw materials, whereas production costs and demands on environmental friendliness increase. This lack largely solves modern conductive textile materials that can be used as a barrier against electromagnetic and electrostatic fields as well as functional electrically conductive structures for use in the manufacture of textile antennas. The basic parameter of these materials is electrical conductivity, which is determined by resistance measurement of the fabric. Production therefore precedes measurement. This paper focuses on optimization of consumption of raw materials by the method of modelling of conductive textile structures so that electrical conductivity can be calculated preferentially to the fabric production. Model focuses on the calculation of resistance of the fabric to derive the electrical conductivity according to the methods specified in the standard EN 1149-1.

Monometallic Textile Electrodes for “Green” Batteries

  • DOI: 10.5755/j01.eee.20.8.8434
  • Link: https://doi.org/10.5755/j01.eee.20.8.8434
  • Department: Department of Telecommunications Engineering
  • Annotation:
    Global trends in the development of modern electrical devices include also eco-friendly demands. One of the areas is seen in environmentally friendly batteries (electrochemical power sources) which do not contain poisonous and heavy metals. Modern structures based on coated textile materials are an alternative to the current all-metal electrodes. The use of environmentally friendly metals often entails the necessity to apply multiple layers of metals, which negatively affects the lifetime of the electrodes and battery cells. Accordingly, this paper focuses on the design and manufacture of monometallic textile electrodes for "green" batteries, i.e. the use of ecological technologies for eco-friendly electronics, especially the new-generation electrochemical power sources. The proposed technological processes were verified by realization of specimens and measurement in laboratory conditions with good results. Industrially applicable technologies were used for applying a thick monometallic deposit to create the specimens. This will allow future mass production and deployment in electrical engineering applications.

Quality of Service and Experience – Business Driven Standardisation for Interoperability in Internet of Things

  • Department: Department of Electrical Power Engineering, Department of Telecommunications Engineering
  • Annotation:
    The phenomenon of the Internet of Things (IoT) brings not only new opportunities in services, but also the requirements for interoperability of various existing technologies and technological systems in converged world. Complex system IoT thus forms a kind of umbrella, allowing more business opportunities. Implementation of modern communication and technology brings great potential especially in the telecommunications, energy, transport and logistic. This article is devoted to the description of opportunities and threats that arise from a new comprehensive system of IoT in individual sectors. It will be also shown that the main measurable criteria to provide the services required in this complex system are to meet the quality of service QoS and quality of experience QoE. It will be shown that these two main criteria are common to all sectors roofed under the umbrella of the Internet of Things in future converged world.

Solar and Wireless Energy Harvesting Semi-active UHF RFID Tag Design and Prototyping

  • Authors: doc. Ing. Lukáš Vojtěch, Ph.D., Kypus, L., Kvarda, L., Thiard, N., Yannis, J.
  • Publication: 16th Mechatronika 2014. Brno: Brno University of Technology, 2014. p. 188-193. ISBN 978-80-214-4817-9.
  • Year: 2014
  • DOI: 10.1109/MECHATRONIKA.2014.7018257
  • Link: https://doi.org/10.1109/MECHATRONIKA.2014.7018257
  • Department: Department of Telecommunications Engineering
  • Annotation:
    In this paper we describe the main phases of an ideation, hardware design, development, prototyping and testing of UHF RFID high memory capacity TAG supported with two external independent power sources. There were used current best practices to design and build a proof of concept with two energy sources: Solar and Wireless which made the TAG battery free and semi-active. Harvested energy should help to support RFID semi-active tag whenever radio signal or light is available. Based on the parallel experience, existing research of similar projects and requirements there was decided to create our own PCB layout for tag board carrying two modules. First source is Solar panel; second one is a Wireless power receiver at frequency of 915MHz. Concerning the RFID circuit Monza Dura family chip as the main microprocessor for RFID transponder was used and a printed PCB antenna as per vendor specification to allow it to interact with remote RFID transmitter. All the system is printed on a FR4 substrate. The main goal was RFID tag reading distance extension. Than it was prototyped and tested the potential of an external power supply for the specific RFID tag based on globally available, harvesting ready RFID chip. In addition to this goal it was validated how does it influence the reading distance and if there will be a positive impact to amplification for more efficient backscatter effect to be able to improve overall Quality of Service. There is a perspective to continue with development and to add other complementary power sources, optimize their switching and management of tag functionalities as well as to fulfill extensive energy requirements for future applications.

Comparison Among Models to Estimate the Shielding Effectiveness Applied to Conductive Textiles

  • Department: Department of Telecommunications Engineering
  • Annotation:
    The purpose of this paper is to present a comparison among two models and its measurement to calculate the shielding effectiveness of electromagnetic barriers, applying it to conductive textiles. Each one, models a conductive textile as either a (1) wire mesh screen or (2) compact material. Therefore, the objective is to perform an analysis of the models in order to determine which one is a better approximation for electromagnetic shielding fabrics. In order to provide results for the comparison, the shielding effectiveness of the sample has been measured by means of the standard ASTM D4935-99.

Control Procedure of Emergency Calls for Femtocells

  • Department: Department of Telecommunications Engineering
  • Annotation:
    Fourth generation (4G) of cellular wireless standards includes small base stations, located at individual buildings as homes or other separated areas, called femtocells. They provide higher transfer rate and level of received signal. These small and low-power cellular base stations can provide a wide-range of military applications – while they can easily be set for closed and from environment isolated areas (or buildings) such as headquarters, ships, airplanes, trains etc. [1]. This technology allows to extend service coverage indoors or at the edges where direct access would be unavailable or limited. The safe and secure internal communication and data exchange channels are offered with possibility of external (internet) connection. Several standards bodies, such as 3GPP, WiMAX Forum, and IEEE 802.16, have started to develop standard solutions to enable and optimize femtocells operation [2]. Despite of possible advantages of WiMAX solution [3] the whole technology is solved by 3GPP group, including emergency call cases. However, they are not described and published in deep detail for close subscriber group (CSG). The paper focuses on proposal of two control procedures which allow an access to CSG in the case of emergency calls.

Design of Radiofrequency Protective Clothing Containing Silver Nanoparticles

  • Department: Department of Telecommunications Engineering
  • Annotation:
    Electromagnetic shielding materials find their use not only at electrical devices construction, but also at personnel protective aids construction of fitters and maintenance workers of power devices under operation. Standards about effects of electromagnetic fields are published and producers manufacture protective aids, suits, etc. especially for antenna systems in microwave frequency bands, which power levels of electromagnetic fields exceed required hygiene limits. However, performance of protective clothing applications is still discussed in radio frequency band. Research of textile material properties shows different ways of production conductive material. Most of them embody some disadvantage considering protective clothing construction, i.e. versatility, peeling, etc. However, using silver nanoparticles increases product manufacture qualities. Therefore the paper focuses on proposal of construction design of protective clothing structure using silver nanoparticles, standardization of effects of electromagnetic fields, measurement and simulations of such material. The results show satisfactory values of electromagnetic shielding efficiency, i.e. about 40 dB (30 MHz – 1.5 GHz). Considering the most unprotected parts, i.e. eyes, mouth and nose, measurement results of hoods reach about 15 dB. Our experiments show the protective clothing can be manufactured form textile material with silver nanoparticles and with breathable and transparent material, which protects eyes, mouth and nose.

Embedded System with RFID Technology and Inductive Proximity Sensor

  • Department: Department of Telecommunications Engineering
  • Annotation:
    Monitoring of technology processes is crucial for quality management and also for effectiveness of following logistics chain to achieve customer expectations and requirements. This leads the author of this paper to develop system for technology monitoring based on RFID and induction proximity sensor, which can be used to monitor and identify movement of goods, components or mechanical parts of the machines in many types of industry. This system has been developed in Centre of Automatic Identification at CTU in Prague. The paper focuses on full description of the system and its evaluation in real operation.

Measurement of Mobile Communication Devices on the Testing Railway Ring

  • Department: Department of Telecommunications Engineering, Department of Computer Science
  • Annotation:
    Paper describes results from the measurement of the transmission system that is designed for active backup of transmission lines through mobile networks. Measurements have been designed and implemented to verify the ability of uninterruptible data transfer during train movement in places with different quality of mobile networks. Testing was realized on the Small test ring of the Railway Research Institute in Velim. We present the results of the measurement on the physical, link and network layer of the reference model ISO / OSI, including results evaluation.

Modelling of Surface and Bulk Resistance for Wearable Textile Antenna Design

  • Department: Department of Telecommunications Engineering
  • Annotation:
    Antennas and other high frequency structure design influence also textile industry in the form of smart textile applications. One of them calls wearable antennas. Proper design of these antennas includes also modelling based on knowledge of textile material parameters of its functional surface, substrate and structure. Paper focuses on modelling of textile structure with electrically conductive fibres and its verification by optic and DC surface and bulk resistance measurement methods.

Radio Frequency Identification of Metal Objects and RF Transparent Containers Filled Up with Liquids

  • Authors: Svub, J., Kebo, V., Unucka, J., doc. Ing. Lukáš Vojtěch, Ph.D.,
  • Publication: Proceedings of International Symposium on Earth Science and Technology 2013. Kyoto: Kyoto University, 2013. pp. 139-142. ISBN 978-4-9902356-2-8.
  • Year: 2013

RFID Textile Antenna and Its Development

  • Department: Department of Telecommunications Engineering
  • Annotation:
    Implementation of textile antennas for RFID tags represents a realistic developmental assignment. The successful operation of such textile antennas mainly requires the mechanical stability of the textile composite, which realizes a RFID tag antenna. A good function of the antenna and thus the sensitivity of the complete tag can be provided for just compliance with the mechanical construction and stability of required dimensions. A good choice of textile material for both electrically conductive structures and the insulating layer of the resultant fabric composite is the most important prerequisite for the successful implementation.

Wearable Textile Electrodes for ECG Measurement

  • Department: Department of Telecommunications Engineering
  • Annotation:
    The electrocardiogram (ECG) is one of the most important parameters for monitoring of the physiological state of a person. Currently available systems for ECG monitoring are both stationary and wearable, but the comfort of the monitored person is not at a satisfactory level because these systems are not part of standard clothing. This article is therefore devoted to the development and measurement of wearable textile electrodes for ECG measurement device with high comfort for the user. The electrode material is made of electrically conductive textile. This creates a textile composite that guarantees high comfort for the user while ensuring good quality of ECG measurements. The composite is implemented by a carrier (a T-shirt with flame retardant) and sensing electrodes embroidered with yarn based on a mixture of polyester coated with silver nanoparticles and cotton. The electrodes not only provide great comfort but are also antibacterial and antiallergic due to silver nanoparticles.

Internet of Things - Where We Are Going

  • Department: Department of Telecommunications Engineering
  • Annotation:
    The paper refers to the Internet of Things phenomenon and Its standardisation process in European Union. Internet of Things will be an umbrella for present identification technologies and other e-technologies.

IoT - Umbrella over Inteligent Subsystems

IoT is not only RFID technology

Modeling of Smart Textile Materials for ESD Applications

  • Department: Department of Telecommunications Engineering
  • Annotation:
    Protection of electronic devices and components against effects of electrostatic discharge is considered as very important part of their production and operating conditions. Many facilities exist such as metal covers and sheets, their grounding, etc. Consumption of specific metal is staggering, therefore modern textile materials can be used instead. Paper focuses on modeling of antistatic textile materials which are compound of non-conductive and conductive fibres. Conductive structure in the textiles enables to distribute the charge and it prevents from undesirable sparks.

Modelling of Electromagnetic Parameters of Planar Textile Materials

  • Department: Department of Telecommunications Engineering
  • Annotation:
    Modern textile materials with increased electric surface conductivity or the ability to shield electromagnetic fields find their application mainly in electrical engineering.

RFID UHF and HF measurement

Self-drying Planar Textile Materials with Electrically Conductive Structures

  • Department: Department of Telecommunications Engineering
  • Annotation:
    Smart textiles expand into different industrial areas and they are not only used to wear. Conductive fabrics serve to antenna design, shielding, cable connection or conducting electrical current for self-drying. The paper focuses on design and simulation of drying abilities of highly conductive textile material. Measurement results are subsequently presented and discussed.

Textile Antenna for 50 Ohm Applications

  • Department: Department of Telecommunications Engineering
  • Annotation:
    The new generation of textile materials have the capability to conduct electricity and at the same time be wearable. There are much more applications involved if an antenna is made from parts that are totally wearable. This new property of conductivity in textile materials is used to implement the wireless functions to clothing. In general, the antennas are made of highly conductive metal with is a solid structure, which results in stable output. The challenge with textile antenna is output stability which is given by pure textile material of the radiating element, dielectric material and also ground, which can be can be folded and twisted. The paper presents the design and fabricated output results of the textile antenna which is used for the 50 ohm system (as GPS or WLAN) at 2,45 GHz.

Verification of Surface Conductance Model of Textile Materials

  • Department: Department of Telecommunications Engineering
  • Annotation:
    Surface conductance is one of the main parameters which describes basic characteristics of specific textile materials. These textile materials are used, for example, in environments with higher requirements on hardware electrostatic protection during their production process. Published measurement standardized methods are followed by modeling methods which do not reach satisfactory results. This paper is therefore focused on the modeling of surface conductance of textile materials. The results show that the structure of textile materials can be seen as serial-parallel connections of resistors. A derivation of this model is described.

Calibration Set for Measuring of Electromagnetic Shielding Efficiency

  • Authors: Ing. Marek Neruda, Ph.D., doc. Ing. Lukáš Vojtěch, Ph.D., Souček, J.
  • Publication: 13th International Conference on Research in Telecommunication Technologies 2011. Brno: VUT v Brně, Fakulta elektrotechniky a komunikačních technologií, 2011. pp. 18-22. ISBN 978-80-214-4283-2.
  • Year: 2011
  • Department: Department of Telecommunications Engineering
  • Annotation:
    Electromagnetic Susceptibility protects electronic devices from unwanted operation or destruction. One of the main instruments can be considered as shielding sheets or barriers. Their effectiveness is measured by parameter called Electromagnetic Shielding Efficiency, which is measured by e.g. standard ASTM D4935-99. It describes dimensions of calibration set, which cannot be bought. Therefore the paper describes design, realization and measurement of calibration set for ESE measurement verification. The importance of ESE value knowledge of different material grows also with the research of effects of electromagnetic field to biological systems.

Microwave RFID - tool for tag minimisation

  • Department: Department of Telecommunications Engineering
  • Annotation:
    Microwave RFID - tool for tag minimisation. This article shows that the production of an RFID transponder with an integrated antenna (OCA - On Chip Antenna) in the X-Band represents a realistic developmental assignment.

Modeling of Textile DC Bulk Resistance for Antenna Design with Electrically Conductive Fibres

  • Authors: Ing. Marek Neruda, Ph.D., doc. Ing. Lukáš Vojtěch, Ph.D.,
  • Publication: Proceedings of the 11th International Conference Knowledge in Telecommunication Technologies and Optics. Ostrava: VŠB - TUO, FEI, Katedra elektroniky a telekomunikační techniky, 2011. pp. 199-202. ISBN 978-80-248-2399-7.
  • Year: 2011
  • Department: Department of Telecommunications Engineering
  • Annotation:
    Development of high frequency applications influences also textile industry with for example wearable antennas. Modeling of these antennas requires knowledge of material parameters of substrates and functional surfaces. This paper focuses on modeling of textile structure with electrically conductive fibres in order to calculate DC bulk resistance. Measurement method is subsequently proposed for model verification.

Planar Materials Electromagnetic Shielding Efficiency Derivation

  • Department: Department of Telecommunications Engineering
  • Annotation:
    Detailed and complete derivation of published models misses in scientific literature and published approximated equations differ from each other in many cases. It can cause unwanted repetition of mistakes in published equations. This paper is therefore focused on derivation of electromagnetic shielding efficiency of planar materials. Derivation obviates discrepancy published in scientific literature and consequently possible incorrect applications in technical practice. Results of modeling and measurement show a strong dependence of shielding efficiency and material electric conductivity and related equivalent sheet model thickness. This result is in accordance with practical experience from EMC branch.

RFID transponders - under the skin

Analysis of Influence of Disturbance Level on Data Transmission in Wireless Networks

  • Department: Department of Telecommunications Engineering
  • Annotation:
    This article is focused on the analysis of the interference effect in the Wireless Local Area Networks (WLAN). The aim of the article is to design concretely the methodology for the optimal wireless device configuration. The optimal parameters can be preciously suggested thanks to the methodology versatility for each of the wireless connection compatible with the IEEE 802.11 standard. The methodology is also applicable to other wireless technologies like IEEE 802.16, radio relay connections, optical links etc.

Application of Shielding Textiles for Increasing Safety Airborne Systems - Limitation of GSM Interference

Data Hardware Protection of Electronic Identifiers

  • Department: Department of Telecommunications Engineering
  • Annotation:
    Data protection of personal information contained in electronic identifiers is one of the most important tasks in RFID technology development. This paper is focused on design and development of data hardware protection of electronic identifiers. New developed textile materials based on metallic and polymeric fibers reach electromagnetic shielding efficiency of tens of decibel in a wide frequency spectrum. The paper describes a development of specific application and its testing.

Feasibility of RFID Signal Denoising Using Neural Network

  • Department: Department of Telecommunications Engineering
  • Annotation:
    Radio Frequency Identification signal denoising can be a perspective method for the future intelligent Radio Frequency Identification readers with high reading distances capability. This paper deals with the Group Method of Data Handling neural network denoising filter experiments. Capability of the probability learning of the Group Method of Data Handling filters is an effective instrument in more exacting applications in comparison with classical Finite Impulse Response filters. Results show that the realized experiment can be a perspective method for Radio Frequency Identification signal processing.

Internet of (clever) things

Laboratory Exercise - Measurement of Electromagnetic Shielding Efficiency

  • Department: Department of Telecommunications Engineering
  • Annotation:
    The new laboratory exercise dealing with measurements of shielding efficiency of new textile materials, increasing the overall knowledge about electromagnetic compatibility.

Measurement of Electromagnetic Shielding Efficiency of Planar Textiles in Frequency Range 100 kHz - 1.5 GHz

  • Department: Department of Telecommunications Engineering
  • Annotation:
    This article describes measuring workplace realization for measurement of electromagnetic shielding efficiency of planar textiles in frequency range 100 kHz - 1.5 GHz. The workplace is used for education of students and also for research and development projects of PhD students.

Measurement of High-frequency RFID Signal

Near Field On Chip RFID Antenna Design

  • Authors: Vargas, A., doc. Ing. Lukáš Vojtěch, Ph.D.,
  • Publication: Radio Frequency Identification Fundamentals and Applications Design Methods and Solutions. Vukovar: Intech, 2010. p. 111-126. ISBN 978-953-7619-72-5.
  • Year: 2010
  • Department: Department of Telecommunications Engineering
  • Annotation:
    This chapter deals with the designing strategy and process integration for a small On-Chip- Antenna (OCA) with a small Radio Frequency Identification (RFID) tag on a chip-area 0.64 x 0.64 mm at 2.45 GHz for communication in near field.

Nonsilicon RFID technology and its future

RF Protective Clothing Developement

  • Authors: Ing. Marek Neruda, Ph.D., doc. Ing. Lukáš Vojtěch, Ph.D.,
  • Publication: Proceedings of the 2010 Networking and Electronic Commerce Research Conference. Dallas, TX: American Telecommunications Systems Management Association Inc., 2010. pp. 203-207. ISBN 978-0-9820958-3-6.
  • Year: 2010
  • Department: Department of Telecommunications Engineering
  • Annotation:
    This paper is focused on development of protective clothing for personnel maintaining mounting work and service near antenna systems during their full operation.

RFID - Instrument for the Tax Administration

  • Department: Department of Telecommunications Engineering
  • Annotation:
    RFID is a perspective instrument for the tax administration. The lecture is about financial benefits and the tax administration application security.

RFID Lab

Surface Conductance of Textile Materials Modeling

Full Face Hood for Electromagnetic Shielding

  • Department: Department of Electromagnetic Field, Department of Telecommunications Engineering
  • Annotation:
    Two prototypes of human head protective hood were developed in the project called BE-TEX "Human and technology protection against high frequency radiation - research and development of new textiles". Interesting results of shielding efficiency were achieved by specially prepared yarn and suitable construction of full face hood. The shielding efficiency defines an attenuation of high frequency signal after spill by shielding material. Measurement results were gained in 500 MHz frequency range. Electric field intensity was compared for situations with ad without fool head hood.

Laboratory Exercises for Optical and Metallic Networks Measurements

  • Department: Department of Telecommunications Engineering
  • Annotation:
    A subject called Basic measurements in telecommunication technology X37MST was modernized by several laboratory exercises focused on data networks and data transfer issues. Students have to study possibilities of optical and metallic networks analyses based on Ethernet technology.

Measurement of electromagnetic shielding efficiency of planar textiles

  • Department: Department of Telecommunications Engineering
  • Annotation:
    New types of textiles were developed in the project Be-Tex, which is focused on human and technology protection against high frequency radiation. The shielding effectiveness defines an attenuation of high frequency signal after spill by shielding material. These textiles can reduce an effect of intensities of electromagnetic fields, which protect human body.

Power Analysis of Communication of RFID Transponders with Password-protected Memory

  • Authors: doc. Ing. Lukáš Vojtěch, Ph.D., Kahl, J.
  • Publication: The Eighth International Conference on Networks (ICN 2009). Los Alamitos: IEEE Computer Society, 2009. pp. 116-120. ISBN 978-1-4244-3470-1.
  • Year: 2009
  • DOI: 10.1109/ICN.2009.75
  • Link: https://doi.org/10.1109/ICN.2009.75
  • Department: Department of Telecommunications Engineering
  • Annotation:
    This paper deals with the method of attacking RFID transponders with a memory protected by an access password. By means of a practical experiment we will demonstrate that the method of protecting the memory space with a user password may not be sufficient.

Quality and production security in galvanic technology

RFID - A Technology for the Internet of Things

  • Department: Department of Telecommunications Engineering
  • Annotation:
    RFID ( Radio Frequency Identification Device) is one of the most evolving technology nowadays, which is used for marking objects or data collection. This technology implementation in area of resolving provider-receiver relationships worldwide caused creation of some kind of new network. Because this RFID technology has application to persons and objects, some kind of objects internet come into being. In this new network space circulate data about particular objects and their properties. In this way each marked object creates some kind of packet movement in layer of physical objects, but information about it flow in virtual paths layer, which use standard data networks. How does the objects internet looks like? What are its basic structural blocks? How do those information flow in this network? How and by who are shared public and classified data?

Basic Measurements in Telecommunications - Laboratory Courses Innovation

  • Department: Department of Telecommunications Engineering
  • Annotation:
    The main goal of our project is an innovation of laboratory exercises of subject "Basic measurements in communication." A part of our solution is a creation a new laboratory exercises, which comprises in concentrate form basic measurements in telecommunication. There are three new separate measuring workplaces. In this subject students acquaint oneself with basic measuring principles, new technologies and ways of verification of their features.

RFID Transponder in X-Band and Its Feasibility

  • Authors: doc. Ing. Lukáš Vojtěch, Ph.D.,
  • Publication: Second International Conference on Sensor Technologies and Applications 2008 (SENSORCOMM '08). Los Alamitos: IEEE Computer Society, 2008. pp. 99-102. ISBN 978-0-7695-3330-8.
  • Year: 2008
  • DOI: 10.1109/SENSORCOMM.2008.68
  • Link: https://doi.org/10.1109/SENSORCOMM.2008.68
  • Department: Department of Telecommunications Engineering
  • Annotation:
    The RFID technology is one of the most quickly developing technologies of the present time. There are various applications of wireless identifiers and they are used in many fields of security as well as industrial applications. One of the limiting criteria is the price of the final transponder (tag) which includes the price of the chip and the antenna. If we implement the antenna directly on the chip the resulting price can be decreased by up to dozens of percents. Although the dimensions of antenna structures directly correspond to the wavelength for which they are intended it proves to be prospective to increase the carrier frequency for the communication with the RFID transponder. This article shows that the production of an RFID transponder with an integrated antenna (OCA - onchip antenna) in the X-band represents a realistic developmental assignment.

System for Control and Quality Management in Galvanic Plant

  • Authors: Bařinka, L., doc. Ing. Lukáš Vojtěch, Ph.D.,
  • Publication: 2008 Conference on Human System Interaction. Piscataway: IEEE, 2008. p. 814-819. ISBN 1-4244-1543-8.
  • Year: 2008
  • Department: Department of Telecommunications Engineering
  • Annotation:
    This paper describes experiences with application of quality management in a real galvanic plant. The system was designed for and implemented in a factory creating super abrasive diamond tools.

Attacks on RFID Tag Security

  • Authors: doc. Ing. Lukáš Vojtěch, Ph.D.,
  • Publication: Proceedings CD-ROM of Digital Technologies 2007. Žilina: Slovenská elektrotechnická společnost, 2007. ISBN 978-80-8070-786-6.
  • Year: 2007
  • Department: Department of Telecommunications Engineering
  • Annotation:
    The security and privacy of RFID are main limitations for many global RFID applications e.g. labels in markets. The cost of RFID transponder is important economical parameter too. Security and privacy are necessary humane and philosophy arguments, but the cost of security and privacy is the biggest part of transponder price. These days we are looking for low-cost cryptography algorithms which will be resistant on potential security attacks. Attacks on RFID Security are one of the most important topics in the area of RFID hardware development. Because there is a potential chance of unauthorized tag reading, due to the contact less data transfer between the Tag and RFID reader, we need good studies of potential attacks mechanisms for accurate hardware design.

Low Cost Noise Sources

  • Authors: doc. Ing. Lukáš Vojtěch, Ph.D.,
  • Publication: 2007 IEEE International Symposium on Electromagnetic Compatibility. Piscataway: IEEE, 2007. pp. 1-3. ISBN 1-4244-1350-8.
  • Year: 2007
  • Department: Department of Telecommunications Engineering
  • Annotation:
    This paper presents a few types of low cost broadband noise sources. Designed and practical working models could be helpful for everybody who needs to assemble cheap, but good working devices.

Measuring Instrument for the Optical Interface MOI/FMOI

  • Authors: Kocourek, T., Davidovič, T., doc. Ing. Lukáš Vojtěch, Ph.D.,
  • Publication: Proceedings CD-ROM of Digital Technologies 2007. Žilina: Slovenská elektrotechnická společnost, 2007. ISBN 978-80-8070-786-6.
  • Year: 2007
  • Department: Department of Telecommunications Engineering
  • Annotation:
    We are working on the new measuring instrument for the optical interface MOI/FMOI these days. This project is realized in the Sitronics center. Sitronics center is a new technology incubator which was established be FEE-CTU in Prague and Sitronics TS Company. Main idea of this incubator is the cooperation between the education and production sector. The "Optical Interface" project has separate parts (project timing). Each part is assigned to one student from the project group. Our objectives are problem analyses, bibliographic search, block scheme design, prototype realization and programming, testing and final documentation creation. Measuring instrument is designed for application in the Sitronics TS Company and will be used for measuring and testing of communication blocks in the MEDIO telecommunication system.

On Chip RFID Antenna

  • Authors: doc. Ing. Lukáš Vojtěch, Ph.D., Vargas, A.
  • Publication: RTT 2007. Žilina: University of Žilina, 2007. pp. 459-462. ISBN 978-80-8070-735-4.
  • Year: 2007

Real Time Chord Recognition

  • Authors: doc. Ing. Lukáš Vojtěch, Ph.D., Bouih, H., Durieux, F.
  • Publication: Proceedings CD-ROM of Digital Technologies 2007. Žilina: Slovenská elektrotechnická společnost, 2007. ISBN 978-80-8070-786-6.
  • Year: 2007
  • Department: Department of Telecommunications Engineering
  • Annotation:
    A method is presented for recognizing chords in real-time played by acoustic instruments, for example a guitar. The method is based on the extraction of chromagrams.

RFID - A Technology for Radio Frequency Contactless Identification

  • Authors: doc. Ing. Lukáš Vojtěch, Ph.D., Píšová, P.
  • Publication: Moderní trendy v digitálních přenosových systémech. Praha: Česká elektrotechnická společnost, 2007. pp. 39-42. ISBN 978-80-02-01922-0.
  • Year: 2007

RFID Disc Antenna

  • Department: Department of Telecommunications Engineering
  • Annotation:
    The antenna presented in this paper operates within the 2.45GHz frequency band, occupies a die area of approximately 400mm2 and is fabricated in a 35um copper foil layer.

Collective Authoring of Electronic Study Materials

Collectively Prepared Learning Courses and Their Use in Class Server Environment

  • Authors: doc. Ing. Lukáš Vojtěch, Ph.D.,
  • Publication: Research in Telecommunication Technology 2006 - Proceedings. Brno: Vysoké učení technické v Brně, 2006. pp. 57-59. ISBN 80-214-3243-8.
  • Year: 2006

Digital Signal Processing and its Impact on RFID Security

RFID Signal Filtering

  • Authors: doc. Ing. Lukáš Vojtěch, Ph.D.,
  • Publication: Proceedings of Workshop 2006. Praha: České vysoké učení technické v Praze, 2006. pp. 282-283. ISBN 80-01-03439-9.
  • Year: 2006
  • Department: Department of Telecommunications Engineering
  • Annotation:
    The RFID (Radio Frequency Identification Device) is one of the most popular technologies at the present. These systems are used in logistic, personalization and in other applications for identification. One of the main limits, for using of the RFID (Radio Frequency Identification Devices), is the maximum reading distance between transmitter and the reader. Maximum distance is a function of the signal quality and the electromagnetic compatibility regulations limits. Using of the signal processing methods could be an interesting way for increasing of the reading distances.

RFID Transponders with Surface Acoustic Wave

The Low-Cost Hash Function Simulation for RFID

  • Authors: Stránský, R., doc. Ing. Lukáš Vojtěch, Ph.D.,
  • Publication: Research in Telecommunication Technology 2006 - Proceedings. Brno: Vysoké učení technické v Brně, 2006. pp. 395-399. ISBN 80-214-3243-8.
  • Year: 2006

Broadband Source of Interference

  • Authors: doc. Ing. Lukáš Vojtěch, Ph.D.,
  • Publication: RTT 2005 Proceedings. Ostrava: VŠB - TUO, FEI, Katedra elektroniky a telekomunikační techniky, 2005. ISBN 80-248-0897-8.
  • Year: 2005

Methods for Low-Cost RFID Security

  • Authors: doc. Ing. Lukáš Vojtěch, Ph.D.,
  • Publication: RTT 2005 Proceedings. Ostrava: VŠB - TUO, FEI, Katedra elektroniky a telekomunikační techniky, 2005. ISBN 80-248-0897-8.
  • Year: 2005

RFID Signal Processing with Neural Network

  • Authors: doc. Ing. Lukáš Vojtěch, Ph.D.,
  • Publication: RTT 2005 Proceedings. Ostrava: VŠB - TUO, FEI, Katedra elektroniky a telekomunikační techniky, 2005. ISBN 80-248-0897-8.
  • Year: 2005

SAW-RFID Transponders

  • Authors: doc. Ing. Lukáš Vojtěch, Ph.D.,
  • Publication: RTT 2005 Proceedings. Ostrava: VŠB - TUO, FEI, Katedra elektroniky a telekomunikační techniky, 2005. ISBN 80-248-0897-8.
  • Year: 2005

GSM Onboard in Aircraft - Interference form Cellular Phones

  • Authors: doc. Ing. Lukáš Vojtěch, Ph.D.,
  • Publication: COFAX-TELEKOMUNIKÁCIE 2004 - zborník prednášok. Bratislava: D&D STUDIO, 2004. pp. 231-232. ISBN 80-967019-6-7.
  • Year: 2004

Method of Registering and Protecting Goods

  • Authors: doc. Ing. Lukáš Vojtěch, Ph.D.,
  • Publication: COFAX-TELEKOMUNIKÁCIE 2004 - zborník prednášok. Bratislava: D&D STUDIO, 2004. pp. 329-330. ISBN 80-967019-6-7.
  • Year: 2004
  • Department: Department of Telecommunications Engineering
  • Annotation:
    The principle of the new method is to attach to the product a data storage medium with contactless data transmission. The base is an application of RFID (Radio Frequency Identification Devices).

The Identification and Localization of the Convicted People

  • Authors: doc. Ing. Lukáš Vojtěch, Ph.D.,
  • Publication: RTT 2004. Praha: ČVUT FEL, Katedra telekomunikační techniky, 2004. pp. 0139_0073. ISBN 80-01-03063-6.
  • Year: 2004
  • Department: Department of Telecommunications Engineering
  • Annotation:
    House arrest (with or without electronic monitoring) allows a person who is sentenced to a jail term to spend the time at his home as an alternative to being physically confined to jail. There are more methods used to the identification of the persons. These systems are designed for an identification of the convicted people. Systems are using the electronic monitoring equipment, installed in an offender's residence with communication via landline. The new method of an electronic monitoring system, which is using the GSM network, is possible to identification and localization of persons. This mobile system could be secure and relatively inexpensive way to the hardware implementation of house arrest or other judicial restrictions.

Responsible person Ing. Mgr. Radovan Suk