The electromagnetic wave absorption characteristics of composite cement-based building material have attracted much interest in recent times. Researchers have mainly focused on the 2 GHz to 12 GHz frequency range. Mobile and wireless communication systems use frequencies from 800 MHz upwards. The determination of characteristics such as reflection loss, absorption, attenuation and shielding effectiveness are crucial in the evaluation and development of these materials for the building industry. Absorption is an indication of how much of the EMW energy enters the material. Attenuation indicates how much of the absorbed energy is converted into other forms of energy by the material. Shielding effectiveness (SE) is a combination of reflection loss, attenuation and multiple internal reflections and attenuations. This research determined these characteristics by measuring the S11 and S21 parameters of the composite cement-based material in the GSM and WiFi frequency bands. The time domain gating function of a vector network analyser is applied to measure the reflection from the material. The data was then used to obtain the reflection and absorption losses in the frequency bands. The transmission loss was measured by placing the sample in the propagation path between two antennas. MnZn-ferrite and electrolytic manganese dioxide in powder form were evaluated as absorber material to increase the permeability of the cement-based material to improve absorption and attenuation capabilities to create a cost-effective practical electromagnetic wave absorber. The compound of the cement-based material was cement, sifted river sand and filler powder. The results achieved in the research showed the uniqueness of electrolytic manganese dioxide as filler in composite cement based material for electromagnetic wave shielding effectiveness improvement. The combined measurement techniques used in this research were uniquely used to determine the required electromagnetic wave absorption characteristics and shielding effectiveness of 10 dB was measured in the GSM850 and GSM900 frequency bands. / Dissertation (MEng)--University of Pretoria, 2013. / gm2014 / Electrical, Electronic and Computer Engineering / unrestricted

This thesis deals with design, development and testing of device for collecting fly data in ultralight airplane or helicopter. The basic collected value is a count of fly hours of each pilot. Additional fly data are latitude, longitude and altitude. Purpose of this device is a fair pricing for use of the airplane. Another utilization is in analysis of flight path or in pilot training. This device is succesfully made from miniature computer Raspberry Pi and uses GPS data. A reader will be informed about aviation regulations, embedded systems, global positioning system and wireless internet connection.

Master’s thesis deals with the design of development kit for communication between a microcontroller and a computer using USB, Bluetooth, WiFi and Ethernet interfaces. In the theoretical introduction is the analysis of theese interfaces and the interfaces used for communication by the microcontroller. In the next part, components for the development kit are selected. Then a wiring diagram and the printed circuit board is designed. Next, the firmware design is described. The last chapter deals with the implementation and testing of the development kit. The appendix contains a proposal for a laboratory task to introduce the development kit to students.

In situations where information infrastructure is destroyed or not available, on-demand information infrastructure is pivotal for the success of rescue missions. In this paper, a drone-carried on-demand information infrastructure for long-distance WiFi transmission system is developed. It can be used in the areas including emergency response, public event, and battlefield. In years development, the Drone WIFI System has developed from single-CPU platform, twin-CPU platform, Atmega2560 platform to NVIDIA Jetson TX2 platform. By the upgrade of the platform, the hardware shows more and more reliable and higher performance which make the application of the platform more and more exciting. The latest TX2 platform can provide real time and thermal video transmission, also application of deep learning of object recognition and target tracing. All these up-to-date technology brings more application scenarios to the system. Therefore, the system can serve more people in more scenarios.

The graduation thesis deals with AT commands and the implementation of these in modules of wireless communication. These commands are mainly used for the obtaining and setting of different parameters of such modules. A form of the AT commands and a manner in which these are sent to modules are described. For selected wireless modules, there is a set of AT commands determined together with a brief description of the functions of these. A manner of creation of macroblocks for the TeraTerm program is also mentioned; macroblocks are able to establish communication with the module connected and allow for measurement and testing of communication appliances. This is suitable especially for the automation of such a process. As such a system (program) is not widely known, a thorough description of this system is given together with a description of measuring and testing macroblocks. The last part of the thesis deals with the creation of an application enabling the user to control quickly and easily an inserted appliance. A very detailed description of this application is given. Due to an absence of an advanced graphic interface, such an application has not been created by means of a system of macroblocks for the TeraTerm program, but it has been created in the JAVA programming language.

Subject of this thesis was the issue of effectiveness of wireless networks from the perspective of services. Become acquainted with WiFi network standard IEEE 802.11 with protocols and principles of WiFi networks and services. It should be focused on the quality of service QoS. In teoretical part of this thesis are described problems considering wireless networks, layer model and types of nets used in WiFi. Standard IEEE 802.11 is analysed in details including supplements and used packets. Special attention is paid to the quality of service QoS. Next are discussed the principles and application services as VoIP, videoconferencing, video streaming and others in WiFi network. On the basis of obtained knowledge is designed extensive WiFi network with assured supply of services. For modelling and simulation of wireless network is used software development environment Opnet Modeler. Model of wireless network is used to optimize and analyse this wireless communication network. In thesis are also simulated properties of data which are sensitive to delay. In last part of thesis is created a laboratory work, which contains a submission of task, detailed theory, wiring diagram, instructions for elaboration, guidelines for simulation and example of elaboration of task. Work is about comparison of network with used 802.11b and 802.11e standard, and support of quality of service QoS.

This master’s thesis deals with design of the regulation of a circulating pump in a solar system for heating of supply water and design of the regulator for this system. It describes a fundamental principle and layout of a regulated circuit of a heating system. Description of regulation, basic terms, properties and differences between different types of regulation are described in first part of the master’s project. Especially continuous (PID regulator) and discrete (PSD regulator) regulation are presented. Second part of the master’s project is focused on a conceptual design of the circulating pump regulator. The connection system of each part, selection conditions of components and connection scheme of regulator are described. The third section deals with design of controlling algorithm of the regulator. There is a detailed description of libraries and functions in each chapter which were used in programming of PSD regulator algorithm. The regulated system of a solar collector is described at the end of the work. This system is being developed for real testing and setting of regulator.

Diploma thesis is focused on the supporting of Quality of Services in wireless networks, especially in the Linux operation systems. The topic is connected not only with OS, but also with the wireless standard, which supports QoS in wireless networks called IEEE 802.11e. QoS is needed especially for time-consuming data transfers in real time. The theoretical part deals with the theoretical analysis of the issue of the QoS support. There are described parameters, which occurred in quality of services support. This section also deals with the division of services that are used to transmit data across computer networks. It also describes the QoS support in wireless networks according 802.11e, its implementation and methods of accessing a medium with a without possibility of traffic. This part is followed by a description of QoS support in UNIX operating systems. The chapter describes how is the QoS support designed in these operating systems. There are also characterized concrete tools which are used for control the data flow in the operating systems using Linux. At the end the theoretical part deals with different types of queues and methods used in linux OS. In the practical part of the thesis, there are various designed topologies and scenarios to verify the functionality of QoS support in wireless networks using a Unix system. These chapters show the results of different tests at selected transmission data streams that are sensitive to transmission time. There is also verified cooperation of QoS support between devices operating on the network and data link layers. The output of this work is to design a laboratory exercise for the subject Network Architecture. This exercise is focused on familiarization with the QoS support functionality in wireless networks and in Unix-like operating systems. This chapter also describes the devices and programs that are needed to measure this task. The last part of the chapter describes the procedure for the preparation of the measuring station. For this laboratory task, there is an inserted manual in the annex.

This work deals with design and realization od an application for Pocket PC which displays wireless networks on a map. The goal of this project is to display signal coverage of an area together with a base station. This paper also deals with GSM localization. The main part describes station position calculation, concept and implementation of the application. In the end there are suggestions for future development of the application.

This master’s thesis deals with the concept of passive multistatic radar. The radar system exploits WiFi or WiMAX transmitters as the source of radiolocation signal. The transmitters are considered non-cooperative. The master’s thesis evaluates limitations arising from utilization of WiFi or WiMAX signals. A Matlab simulator was created as a part of the thesis, which was used to verify the basic idea behind this concept. Based on the results of real-life simulations, conclusions are suggested towards a possible application of WiFi/WiMAX radar.