Karel Vlcek

Antenna of silver nanoparticles mounted on a flexible polymer substrate constructed using inkjet print technology

This article describes the construction of an antenna that operates at frequencies of 1.07, 1.5, and 2.49 GHz and that is fabricated on a flexible polymer substrate using inkjet printing technology. In particular, this article is focused on the preparation and characterization of an antenna starting from the ink formulation for printing a homogeneous, electrically conductive layer using silver nanoparticles. The diameter of the prepared silver nanoparticles ranges from 50 to 200 nm. The inkjet printing technology on flexible polymer substrates offers a wide range of applications where there are high demands for flexibility. In combination with the polymer substrate, inkjet printing enables the production of more complex shapes and curves for antennas that are widely applicable not only in wearable electronic devices but also in plastic cases for portable communication devices.

Image Encryption In Wavelet Domain Based on Chaotic Maps

It is commonly known that chaotic systems are extremely sensitive to initial parameters and these systems can be very helpful in the field of cryptography from this reason. Logistic maps of deterministic chaos can be used for the generation of encryption key. This key is then used for the image encryption. This paper proposes usage of chaotic encryption and its application in the wavelet domain of dyadic decomposed image. Modification of wavelet components leads to massive degradation of image. Decryption with unauthorized key is very difficult due to the initial parameter sensitivity of this encryption scheme. Keywords-component; encryption; decryption; wavelet; domain; chaotic maps;

The Multifunctional Composite on the Base of Carbon Nanotubes Network and its Use as a Passive Antenna and Gas Sensing Element

Carbon nanotubes in the form of entangled network can be used as a multifunctional composite material for a wide range of using. A new and perspective usage is a passive antenna and gas sensing element. The antenna works well at 1.284 GHz. The local reflection minimum is 11.48 dB. The reflection coefficient r=0.2667. The transmission power in this frequency is 93%. Multiwall carbon nanotubes (MWCNT) network Buckypaper was made by the vacuum filtration method of MWCNT aqueous suspension. The sensitivity of multi-wall carbon nanotube (MWCNT) networks of randomly entangled pure and HNO3 oxidized nanotubes to polar and nonpolar organic vapors (ethanol, heptane), has been investigated by resistance measurements. The results demonstrate that the network electrical resistance increases when exposed to organic solvent vapors, and a reversible reaction is observed when the sample is removed from the vapors. The investigated MWCNT networks could be potentially used as sensing elements for sensitive and selective organic vapor detection.

Hardware solution of chaos based image encryption

Many image encryption schemes based on chaotic iterative maps are very expensive in terms of processing speed. This inconvenient feature causes the inapplicability in real-time processes. Hence, encryption scheme must be projected at low-level. This paper proposes hardware solution of image encryption with keeping the high security of encrypted image and speeding up the encryption process.

LDPC Binary Vectors Coding Enhances Transmissions and Memories Reliability

The paper interests in the research and implementation of memory coded information by modulation with highly effective concatenated codes, represented by LDPC (Low Density Parity Check) codes. Parameters optimization of coding is solved with respect to its implementation by semicustom integrated circuit of gate array and highly effective ARM processor created as SoC (System on Chip). Vendors offer a lot of types programmable circuits and software environments for this technique now. Basic modelling technique is model creation and simulation special architectures described by modeling in C/C++, and SystemC languages. The basic idea – the instruction set extension of the ARM processor – is realized by freely programmable gates as special “data flow” controlled execution unit and additional instruction decoder.

Model of Surveillance System Based on Sound Tracking

Research in the audio and video surveillance is gaining more popularity due to its wide-spread applications as well as social impact. There have been considerable efforts which are focused on developing various algorithms and models for surveillance systems. Recently, the attention in audio and video surveillance has turned towards to design autonomous detection system. In this paper a surveillance system based on sound source localization by a microphone array is presented. The design of microphone array has an important issue in the accuracy of source localization. For the surveillance application, beamforming algorithms are implemented to increase the tracking and detection performance. The real-time capabilities of an automated surveillance system are analyzed, providing a performance analysis of the localization system under different acoustic conditions.

The TBU software branch exchange laboratory

This paper describes the implementation of a software branch exchange laboratory at Tomas Bata University in Zlin. The exchange is based on GNU/Linux and Asterisk software and is used in the Telecommunication Systems course tuition process. It serves for the interconnection of additional exchanges and has a connection to the PSTN (Public Switched Telephone Network). Students create their own exchanges on their PC (using OS GNU/Linux and Asterisk virtualization). The Laboratory Exchange has a higher hierarchy status in the connection scheme.

GPU Benchmarks Based On Strange Attractors

The main purpose of presented GPU benchmark is to generate complex polygonal mesh structures based on strange attractors with fractal structure. Attractors have to be created as 4D objects using quaternion algebra. Polygonal mesh can have different numbers of polygons because of iterative application of this system. The major complexity of every mesh would provide efficient results using multiple methods such as ray-tracing, anti aliasing and anisotropic filtering to evaluate GPU performance. Our main goal is to develop new faster algorithm to generate 3D structures and apply its complexity for GPU benchmarking.

Chaos-Based Bit Planes Image Encryption

Bit planes of discrete signal can be used not only for encoding or compressing, but also for encrypting purposes. This paper investigates composition of bit planes of an image and their utilization in the encryption process. Proposed encryption scheme is based on chaotic maps of Peter de Jong and it is designed for image signals primarily. Positions of all components of bit planes are permutated according to chaotic behaviour of Peter de Jong’s system.

B18: Multichannel analog-to-digital converter module with variable gain

Abstract For measurement of some analog signal as voltage, current, resistance etc. and for a different input signal level on multichannel single-ended analog-to-digital converter is necessary to have a variable gain for all input channels. The proposed solution is based on an instrumental operational amplifier on an input stage, where gain level reaches value of 384. An operational amplifier with gain level between 1 and 30 and with offset voltage control is used in the middle stage. Module is ended by 16-bit analog-to-digital converter with a parallel interface compatible with digital signal processors, microcontrollers etc.