Browse

You are looking at 101 - 110 of 508 items for :

  • Information Technology x
Clear All
Open access

András Kelemen, Domokos Biró, Albert-Zsombor Fekete, László Jakab-Farkas and Róbert Rossi Madarász

Abstract

The presence of a second reactive gas in the magnetron sputtering chamber makes the process much more complicated, and the process control much more difficult than in the case of a single reactive gas. Macroscopic models have been developed in order to explain the complex phenomena and to provide support for the process control. These models are able to explain the nonlinearities of the process and the strong coupling between the control channels.

This paper introduces a model created with the intention to of gaining a good grasp of the process, especially regarding the conditions necessary to obtain the required stoichiometry of the film deposited on the substrate. For this purpose, we modelled the formation of the desired ternary compound both directly from the available particle fluxes and from intermediary compounds. The surface of the substrate is divided into eight dynamically variable regions, covered by different compounds, each exposed to the streams of five types of particles.

We present the analytical model and provide simulation results in order to demonstrate its capability toof describeing the nonlinear phenomena, which that characterisze the two-gas sputtering process.

Open access

Raushan Kumar, Sahadev Roy and C.T. Bhunia

Abstract

In this paper, we proposed an efficient full adder circuit using 16 transistors. The proposed high-speed adder circuit is able to operate at very low voltage and maintain the proper output voltage swing and also balance the power consumption and speed. Proposed design is based on CMOS mixed threshold voltage logic (MTVL) and implemented in 180nm CMOS technology. In the proposed technique the most time-consuming and power consuming XOR gates and multiplexer are designed using MTVL scheme. The maximum average power consumed by the proposed circuit is 6.94μW at 1.8V supply voltage and frequency of 500 MHz, which is less than other conventional methods. Power, delay, and area are optimized by using pass transistor logic and verified using the SPICE simulation tool at desired broad frequency range. It is also observed that the proposed design may be successfully utilized in many cases, especially whenever the lowest power consumption and delay are aimed.

Open access

András Szabó

Abstract

UAS (Unmanned Aerial Systems) are commonly used in 3D (dull, dirty and dangerous) missions, because these are not endangering the operators life, while reduce maintenance costs and increase maneuvering capabilities. Despite of these advantages we should consider the possible vulnerabilities of this technology as well. Unmanned vehicles can be controlled via direct communication link, or they can work in a preprogrammed mode. Usually the preprogrammed mode is based on radio navigation systems, so we can draw a conclusion that both depend on the RF environment. In this paper I analyze a possibility to effectively evaluate the communication link of an UAS. Developers have to consider several key factors (type of operation, endurance, payload type and size, propulsion, communication link, etc.) during the development process. They are also responsible that the final product meets the predefined requirements. On the other side commercial UAS owners should have a possibility to compare and evaluate the UAS before the acquisition. Finally, operators and frequency management entities need tools to diagnose the possible sources of interference regarding the unmanned vehicles. To understand the consequences of interference in the RF spectrum we have to be able to measure the quality of the communication link in different usage scenarios. In my research I evaluate the usage of SDRs (Software Defined Radios) in RF Test and Evaluation processes. After analyzing the possibilities for a flexible testbed, I demonstrate the usability with some measurements in the GNU Radio signal processing framework.

Open access

Örs Darabont, Konrád József Kiss and József Domokos

Abstract

This paper presents an evaluation of different methods used to deliver virtual machines capable of being accessed remotely by thin-clients. The objective of the research was to provide a recommendation for building a cost-effective computer infrastructure for use in two scenarios: as a programming lab, and as an office infrastructure.

We have found that different thin-client solutions based on single board computers are reliable solutions for commercially available thin client replacement, because they can run free Linux-based operating systems, can handle Remote Desktop Protocol, have lower acquisition costs, lower power consumption and offer almost the same computing performance.

For providing remote desktops, there are several methods and virtualization platforms available. We benchmarked some of these platforms in order to choose the one best-suited for implementation. Our conclusion is that Microsoft Remote Desktop Services outperforms the virtualization based solutions, but it entails high license fees. Of the virtualization solutions tested, the VMW are ESXi based one is the most reliable choice.

Open access

Zsófia Sándor and Gergely Kis

Abstract

The proliferation of sensor networks employing wireless data transmission technologies has paved the way for the collection of large amounts of measurement data. Several research teams have used this opportunity to develop algorithms aimed at gaining information from sensor data. Motion detection is one of the most actively researched areas. In this article, we present a system for examining motion detection in a general environment. In other words, motion forms are not identified with various wearable sensors; instead, we use the data collected by the sensors of mobile phones kept with almost all members of society now.

Open access

Łukasz Chruszczyk and Adam Zając

Abstract

This paper compares accuracy of indoor positioning systems using one of three selected ISM bands: 433, 868 or 2400 MHz. Positioning is based on Received Signal Strength Indication (RSSI), received by majority of ISM RF modules, including low-cost ones. Investigated environment is single, indoor space (e.g. office, hall) and personal use, thus 2-dimensional (2D) coordinate system is used. Obtained results, i.a. average positioning error, are compared with similar measurements taken at outdoor, open space environment. The system is local, i.e. its operational area is limited by range of used RF modules – typical a few tens of meters. The main focus is research of how much accuracy (and usefulness) can be expected from standard RF modules working at typical ISM frequencies.

Open access

Mariam Abdul-Zahra Raheem and Ehab AbdulRazzaq Hussein

Abstract

The main aim of this paper is to propose Cubic Spline-Quantum Neural Network (CS-QNN) model for analysis and classification of Electroencephalogram (EEG) signals. Experimental data used here were taken from seven different electrodes. The work has been done in three stages, normalization of the signals, extracting the features by Cubic Spline Technique (CST) and classification using Quantum Neural Network (QNN). The simulation results showed that five types of EEG signals were classified with an average accuracy for seven electrodes that is 94.3% when training 70% of the features while with an average accuracy of 92.84% when training 50% of the features.

Open access

Przemysław Gilski and Jacek Stefański

Abstract

Radio is by far the most accessible medium. With its mobility and availability, it attracts listeners by its simplicity and friendliness. The present information situation is characterized by the convergence of computers, mobile devices, telecommunication and broadcasting technologies and the divergence of different ways of delivering and storing media. Consumers are overwhelmed by new electronic gadgets appearing every year. They are astonished by new technical innovations that are being designed to ease their life and change their habits. Even the broadcasting sector itself is facing significant changes, especially a growing competition between the private and public sector. This article reviews the current status of analog and digital broadcasting technologies. It analyzes a case study of user expectations related with today’s digital media, particularly radio transmission. We discuss the principal possibilities, limitations and user expectations related with digital audio broadcasting, as well as the economic, technological, regulatory and frequency management factors.

Open access

Damian E. Grzechca, Piotr Pelczar and Lukas Chruszczyk

Abstract

This paper presents analysis of object location accuracy of a mobile device on the basis of the iBeacon technology. The research starts with radio signal strength indicator analysis along the corridor in order to create a path loss model for iBeacon. Two cases are taken into account: line of sight and non-line of sight for model creation. For both cases two tests: Chi-square, Shapiro-Wilk have been performed. It has also been checked if the HCI (Host Controller Interface) is a source with a memory. Acquired data have been filtered with different type of filters, e.g. median, moving average and then compared. Next, the authors evaluated the indoor positioning trilateration algorithms with the use of created model for exemplary hall. The RSSI map (radiomap) was created and the logarithm propagation model was designed. The logarithmic model estimated distance with average error 1.09m for 1 – 9m and 1.75m for 1-20m and after trilateration, the positions with average error 2.45m was achieved. A statistical analysis for acquiring data led to the final conclusion which enhanced knowledge about positioning based on the popular iBeacon technology.

Open access

Marta Okoń-Fąfara, Piotr Serafin and Adam Kawalec

Abstract

The modelling of FMCW SAR systems, due to long signal duration time, commonly used start-stop approximation for pulsed radars causes errors in the image. Continuous motion of the radar platform results in additional range-azimuth couplings and range walk term that should be considered in processing of signal from this type of radar. The paper presents an analysis of the following algorithms: Time Domain Correlation (TDC), Range Doppler Algorithm (RDA), and Range Migration Algorithm (RMA). The comparison of the algorithms is based on theoretical estimation of their computation complexity and the quality of images obtained on the basis of real signals of FMCW SAR systems.